Cellular and molecular features related to exceptional therapy response and extreme long-term survival in glioblastoma

Glioblastoma Multiforme (GBM) remains the most common malignant primary brain tumor with a dismal prognosis that rarely exceeds beyond 2 years despite extensive therapy, which consists of maximal safe surgical resection, radiotherapy, and/or chemotherapy. Recently, it has become clear that GBM is not one homogeneous entity and that both intra-and intertumoral heterogeneity contributes significantly to differences in tumoral behavior which may consequently be responsible for differences in survival. Strikingly and in spite of its dismal prognosis, small fractions of GBM patients seem to display extremely long survival, defined as surviving over 10 years after diagnosis, compared to the large majority of patients. Although the underlying mechanisms for this peculiarity remain largely unknown, emerging data suggest that still poorly characterized both cellular and molecular factors of the tumor microenvironment and their interplay probably play an important role. We hereby give an extensive overview of what is yet known about these cellular and molecular features shaping extreme long survival in GBM.

KS05.7.A Characterization of the immune composition of extreme long-term survivors with malignant glioma at single-cell level

Background

Glioblastoma Multiforme (GBM) remains the most common malignant primary brain tumor with a dismal prognosis that rarely exceeds beyond two years despite extensive therapy, which consists of maximal safe surgical resection, radiotherapy and/or chemotherapy. Recently, it has become clear that GBM is not one homogeneous entity and that both intra-and intertumoral heterogeneity contribute significantly to differences in tumoral behavior which may consequently be responsible for differences in survival. Strikingly and in spite of its dismal prognosis, small fractions of GBM patients seem to display extended survival compared to the large majority of patients. The underlying mechanisms for this peculiarity remain largely unknown however, even though emerging data suggest that both cancer cell-autonomous and microenvironmental factors and their interplay probably play an important role.

Material and Methods

We used high-dimensional, multiplexed immunohistochemistry to spatially, and cytometry by time-of-flight to quantitively characterize the cell constitution and interactions within the tumor microenvironment (TME) in 21 extreme long-term survivors (living over ten years since primary diagnosis or five years after recurrence) and 42 deeply matched short-term controls (living under 1.5 year) on a single cell level. For all tumors (epi-)genetic data was also collected.

Results

We identified a high level of both inter-and intrapatient heterogeneity defined by several distinct tumor niches, as well as described interactions within these niches and with the surrounding infiltrating immune cells of the TME. By linking patient characteristics with the heterogeneous immune composition we are building an immune stratification that can be linked to patient survival in GBM.

Conclusion

Generating an immune stratification for GBM will allow us to identify immune characteristics responsible for longer or even exceptional survival, as well as thoroughly identify tumor components that may serve as a potential target for personalized treatment strategies. Therefore, this study is also an essential initial step towards such clinical trials which alter the TME in a favorable way with a personalized modulation strategy.

Monocyte-driven atypical cytokine storm and aberrant neutrophil activation as key mediators of COVID-19 disease severity

Epidemiological and clinical reports indicate that SARS-CoV-2 virulence hinges upon the triggering of an aberrant host immune response, more so than on direct virus-induced cellular damage. To elucidate the immunopathology underlying COVID-19 severity, we perform cytokine and multiplex immune profiling in COVID-19 patients. We show that hypercytokinemia in COVID-19 differs from the interferon-gamma-driven cytokine storm in macrophage activation syndrome, and is more pronounced in critical versus mild-moderate COVID-19. Systems modelling of cytokine levels paired with deep-immune profiling shows that classical monocytes drive this hyper-inflammatory phenotype and that a reduction in T-lymphocytes correlates with disease severity, with CD8+ cells being disproportionately affected. Antigen presenting machinery expression is also reduced in critical disease. Furthermore, we report that neutrophils contribute to disease severity and local tissue damage by amplification of hypercytokinemia and the formation of neutrophil extracellular traps. Together our findings suggest a myeloid-driven immunopathology, in which hyperactivated neutrophils and an ineffective adaptive immune system act as mediators of COVID-19 disease severity.

High dimensional profiling identifies specific immune types along the recovery trajectories of critically ill COVID19 patients

The COVID-19 pandemic poses a major burden on healthcare and economic systems across the globe. Even though a majority of the population develops only minor symptoms upon SARS-CoV-2 infection, a significant number are hospitalized at intensive care units (ICU) requiring critical care. While insights into the early stages of the disease are rapidly expanding, the dynamic immunological processes occurring in critically ill patients throughout their recovery at ICU are far less understood. Here, we have analysed whole blood samples serially collected from 40 surviving COVID-19 patients throughout their recovery in ICU using high-dimensional cytometry by time-of-flight (CyTOF) and cytokine multiplexing. Based on the neutrophil-to-lymphocyte ratio (NLR), we defined four sequential immunotypes during recovery that correlated to various clinical parameters, including the level of respiratory support at concomitant sampling times. We identified classical monocytes as the first immune cell type to recover by restoration of HLA-DR-positivity and the reduction of immunosuppressive CD163 + monocytes, followed by the recovery of CD8 + and CD4 + T cell and non-classical monocyte populations. The identified immunotypes also correlated to aberrant cytokine and acute-phase reactant levels. Finally, integrative analysis of cytokines and immune cell profiles showed a shift from an initially dysregulated immune response to a more coordinated immunogenic interplay, highlighting the importance of longitudinal sampling to understand the pathophysiology underlying recovery from severe COVID-19.

Community-acquired pneumonia (CAP) hospitalizations and deaths: is there a role for quality improvement through inter-hospital comparisons?

OBJECTIVE

To assess between-hospital variations in standardized in-hospital mortality ratios of community-acquired pneumonia (CAP), and identify possible leads for quality improvement.

DESIGN

We used an administrative database to estimate standardized in-hospital mortality ratios for 111 Belgian hospitals, by carrying out a set of hierarchical logistic regression models, intended to disentangle therapeutic attitudes and biases. To facilitate the detection of false-negative/positive results, we added an inconclusive zone to the funnel plots, derived from the results of the study. Data quality was validated by comparison with (i) alternative data from the largest Belgian Sickness Fund, (ii) published German hospital data and (iii) the results of an on-site audit.

SETTING

All Belgian hospital discharge records from 2004 to 2007.

STUDY PARTICIPANTS

A total of 111 776 adult patients were admitted for CAP.

MAIN OUTCOME MEASURE

Risk-adjusted standardized in-hospital mortality ratios.

RESULTS

Out of the 111 hospitals, we identified five and six outlying hospitals, with standardized mortality ratios of CAP consistently on the extremes of the distribution, as providing possibly better or worse care, respectively, and 18 other hospitals as having possible quality weaknesses/strengths. At the individuals' level of the analysis, adjusted odds ratios showed the paramount importance of old age, comorbidity and mechanical ventilation. The data compared well with the different validation sources.

CONCLUSIONS

Despite the limitations inherent to administrative data, it seemed possible to establish inter-hospital differences in standardized in-hospital mortality ratios of CAP and to identify leads for quality improvement. Monitoring is needed to assess progress in quality.

Body mass index and HER-2 overexpression in breast cancer patients over 50 years of age

PURPOSE

In breast cancer, in vitro as well as in vivo experiments have shown an inverse relationship between HER-2 and steroid hormone receptors. It is unknown whether circulating estrogens affect HER-2 expression. We hypothesize that the postmenopausal body mass index (BMI) as a surrogate marker for bio-available estrogens, is inversely associated with HER-2 over-expression.

PATIENTS AND METHODS

A total of 535 women over age 50 or with known postmenopausal status, with a unilateral, not previously treated, operable breast cancer were evaluated the evening prior to surgery for body weight, height, abdominal and hip circumference over a 3 years period. Waist-to-hip ratio (WHR) and BMI were calculated. HER-2, estrogen receptor and progesterone receptor staining was done by immunohistochemistry. All tumours with DAKO 2+ staining were submitted for HER-2 detection by FISH analysis. HER-2 was defined as positive if DAKO 3+ or FISH positive. We assessed the frequency of HER-2 positivity in each of 6 quantiles for all parameters of body composition and tested for a trend in HER-2 expression across the 6 quantiles. Furthermore, we investigated whether BMI contributed, together with other known predictors for HER-2, in a standard multivariate logistic regression model that predicts HER-2 over-expression.

RESULTS

There is a decrease in HER-2 over-expression per increasing quantile of BMI. In a multivariate model-including both steroid receptors-BMI remains an independent predictor for HER-2 over-expression.

CONCLUSION

In women over age 50 or with known postmenopausal status with an operable breast cancer, there is an inverse association between BMI and HER-2 over-expression.

Bishop score and ultrasound assessment of the cervix for prediction of time to onset of labor and time to delivery in prolonged pregnancy

OBJECTIVES

To determine the ability of Bishop score and sonographic cervical length to predict time to spontaneous onset of labor and time to delivery in prolonged pregnancy.

METHODS

Ninety-seven women underwent transvaginal ultrasound examination and palpation of the cervix at 291-296 days' gestation according to ultrasound fetometry at 12-20 weeks' gestation. Sonographic cervical length and Bishop score were recorded. Multivariate logistic regression analysis was used to determine which variables were independent predictors of the onset of labor/delivery < or = 24 h, < or = 48 h, and < or = 96 h. Receiver-operating characteristics (ROC) curves were drawn to assess diagnostic performance.

RESULTS

In nulliparous women (n = 45), both Bishop score and sonographic cervical length predicted the onset of labor/delivery < or = 24 h and < or = 48 h (area under ROC curve for the onset of labor < or = 24 h 0.79 vs. 0.80, P = 0.94; for delivery < or = 24 h 0.81 vs. 0.85, P = 0.64; for the onset of labor < or = 48 h 0.73 vs. 0.74, P = 0.90; for delivery < or = 48 h 0.77 vs. 0.71, P = 0.50). Only Bishop score discriminated between nulliparous women who went into labor/delivered < or = 96 h or > 96 h. A logistic regression model including Bishop score and cervical length was superior to Bishop score alone in predicting delivery < or = 24 h (area under ROC curve 0.93 vs. 0.81, P = 0.03) and superior to Bishop score alone and cervical length alone in predicting the onset of labor < or = 24 h (area under ROC curve 0.90 vs. 0.79, P = 0.06; and 0.90 vs. 0.80, P = 0.06). In parous women (n = 52), Bishop score and sonographic cervical length predicted the onset of labor/delivery < or = 24 h (area under ROC curve for the onset of labor 0.75 vs. 0.69, P = 0.49; for delivery 0.74 vs. 0.70, P = 0.62), but only Bishop score discriminated between women who went into labor/delivered < or = 48 h and > 48 h. Three parous women had not gone into labor and six had not given birth at 96 h. In parous women logistic regression models including both Bishop score and cervical length did not substantially improve prediction of the time to onset of labor/delivery.

CONCLUSIONS

In prolonged pregnancy Bishop score and sonographic cervical length have a similar ability to predict the time to the onset of labor and delivery. In nulliparous women the use of logistic regression models including Bishop score and cervical length is likely to offer better prediction of the onset of labor/delivery < or = 24 h than the use of the Bishop score alone.

Three-dimensional ultrasound assessment of the cervix for predicting time to spontaneous onset of labor and time to delivery in prolonged pregnancy

OBJECTIVES

To determine whether three-dimensional (3D) ultrasound including power Doppler examination of the cervix is useful for predicting time to spontaneous onset of labor or time to delivery in prolonged pregnancy.

METHODS

A prospective study was conducted in 60 women who went into spontaneous labor. All underwent transvaginal 3D power Doppler ultrasound examination of the cervix immediately before a prolonged-pregnancy check-up at > or = 41 + 5 gestational weeks. Univariate and multivariate logistic regression analysis was used to determine which of the following variables predicted spontaneous onset of labor > 24 h and > 48 h and vaginal delivery > 48 h and > 60 h: length, anteroposterior (AP) diameter and width of the cervix and of any cervical funneling; cervical volume (cm3); vascularization index (VI); flow index (FI); vascularization flow index (VFI); parity; and Bishop score. Multivariate logistic regression analysis was carried out both with and without Bishop score as a predictive variable. Receiver-operating characteristics (ROC) curves were used to describe the diagnostic performance of the tests.

RESULTS

The areas under the ROC curves for Bishop score, cervical length, and logistic regression models did not differ significantly (areas ranging from 0.72 to 0.82). If Bishop score was not included in the logistic regression model, cervical length, VI and FI independently predicted delivery > 48 h, the likelihood increasing with increasing cervical length, decreasing VI and increasing FI.

CONCLUSIONS

In prolonged pregnancy cervical vascularization as estimated by 3D power Doppler ultrasound is related to time to delivery > 48 h, but the likelihood of delivery > 48 h can be predicted equally well using Bishop score alone or sonographic cervical length alone.

New models to predict depth of infiltration in endometrial carcinoma based on transvaginal sonography

OBJECTIVES

Preoperative knowledge of the depth of myometrial infiltration is important in patients with endometrial carcinoma. This study aimed at assessing the value of histopathological parameters obtained from an endometrial biopsy (Pipelle de Cornier; results available preoperatively) and ultrasound measurements obtained after transvaginal sonography with color Doppler imaging in the preoperative prediction of the depth of myometrial invasion, as determined by the final histopathological examination of the hysterectomy specimen (the gold standard).

METHODS

We first collected ultrasound and histopathological data from 97 consecutive women with endometrial carcinoma and divided them into two groups according to surgical stage (Stages Ia and Ib vs. Stages Ic and higher). The areas (AUC) under the receiver-operating characteristics curves of the subjective assessment of depth of invasion by an experienced gynecologist and of the individual ultrasound parameters were calculated. Subsequently, we used these variables to train a logistic regression model and least squares support vector machines (LS-SVM) with linear and RBF (radial basis function) kernels. Finally, these models were validated prospectively on data from 76 new patients in order to make a preoperative prediction of the depth of invasion.

RESULTS

Of all ultrasound parameters, the ratio of the endometrial and uterine volumes had the largest AUC (78%), while that of the subjective assessment was 79%. The AUCs of the blood flow indices were low (range, 51-64%). Stepwise logistic regression selected the degree of differentiation, the number of fibroids, the endometrial thickness and the volume of the tumor. Compared with the AUC of the subjective assessment (72%), prospective evaluation of the mathematical models resulted in a higher AUC for the LS-SVM model with an RBF kernel (77%), but this difference was not significant.

CONCLUSIONS

Single morphological parameters do not improve the predictive power when compared with the subjective assessment of depth of myometrial invasion of endometrial cancer, and blood flow indices do not contribute to the prediction of stage. In this study an LS-SVM model with an RBF kernel gave the best prediction; while this might be more reliable than subjective assessment, confirmation by larger prospective studies is required.

Predicting the outcome of pregnancies of unknown location: Bayesian networks with expert prior information compared to logistic regression

BACKGROUND

As women present at earlier gestations to early pregnancy units (EPUs), the number of women diagnosed with a pregnancy of unknown location (PUL) increases. Some of these women will have an ectopic pregnancy (EP), and it is this group in the PUL population that poses the greatest concern. The aim of this study was to develop Bayesian networks to predict EPs in the PUL population.

METHODS

Data were gathered in a single EPU from all women with a PUL. This data set was divided into a model-building (599 women with 44 EPs) and a validation (257 women with 22 EPs) data set and consisted of the following variables: vaginal bleeding, fluid in the pouch of Douglas, midline echo, lower abdominal pain, age, endometrial thickness, gestation days, the ratio of HCG at 48 and 0 h, progesterone levels (0 and 48 h) and the clinical outcome of the PUL. We developed Bayesian networks with expert information using this data set to predict EPs.

RESULTS

The best Bayesian network used the gestational age, HCG ratio and the progesterone level at 48 h and had an area under the receiver operator characteristic curve (AUC) of 0.88 for predicting EPs when tested prospectively.

CONCLUSIONS

Discrete-valued Bayesian networks are more complex to build than, for example, logistic regression. Nevertheless, we have demonstrated that such models can be used to predict EPs in a PUL population. Prospective interventional multicentre studies are needed to validate the use of such models in clinical practice.

Predicting the clinical behavior of ovarian cancer from gene expression profiles

We investigated whether prognostic information is reflected in the expression patterns of ovarian carcinoma samples. RNA obtained from seven FIGO stage I without recurrence, seven platin-sensitive advanced-stage (III or IV), and six platin-resistant advanced-stage ovarian tumors was hybridized on a complementary DNA microarray with 21,372 spotted clones. The results revealed that a considerable number of genes exhibit nonaccidental differential expression between the different tumor classes. Principal component analysis reflected the differences between the three tumor classes and their order of transition. Using a leave-one-out approach together with least squares support vector machines, we obtained an estimated classification test accuracy of 100% for the distinction between stage I and advanced-stage disease and 76.92% for the distinction between platin-resistant versus platin-sensitive disease in FIGO stage III/IV. These results indicate that gene expression patterns could be useful in clinical management of ovarian cancer.

Predicting the clinical behavior of ovarian cancer from gene expression profiles

We investigated whether prognostic information is reflected in the expression patterns of ovarian carcinoma samples. RNA obtained from seven FIGO stage I without recurrence, seven platin-sensitive advanced-stage (III or IV), and six platin-resistant advanced-stage ovarian tumors was hybridized on a complementary DNA microarray with 21,372 spotted clones. The results revealed that a considerable number of genes exhibit nonaccidental differential expression between the different tumor classes. Principal component analysis reflected the differences between the three tumor classes and their order of transition. Using a leave-one-out approach together with least squares support vector machines, we obtained an estimated classification test accuracy of 100% for the distinction between stage I and advanced-stage disease and 76.92% for the distinction between platin-resistant versus platin-sensitive disease in FIGO stage III/IV. These results indicate that gene expression patterns could be useful in clinical management of ovarian cancer.

Diagnostic accuracy of varying discriminatory zones for the prediction of ectopic pregnancy in women with a pregnancy of unknown location

OBJECTIVES

Various serum human chorionic gonadotropin (hCG) discriminatory zones are currently used for evaluating the likelihood of an ectopic pregnancy in women classified as having a pregnancy of unknown location (PUL) following a transvaginal ultrasound examination. We evaluated the diagnostic accuracy of discriminatory zones for serum hCG levels of > 1000 IU/L, 1500 IU/L and 2000 IU/L for the detection of ectopic pregnancy in such women.

METHODS

This was a prospective observational study of women who were assessed in a specialized transvaginal scanning unit. All women with a PUL had serum hCG measured at presentation. Expectant management of PULs was adopted. These women were followed up with transvaginal ultrasound, monitoring of serum hormone levels and laparoscopy until a final diagnosis was established: a failing PUL, an intrauterine pregnancy (IUP), an ectopic pregnancy or a persisting PUL. The persisting PULs probably represented ectopic pregnancies which had been missed on ultrasound and these were incorporated into the ectopic pregnancy group. Three different discriminatory zones (1000 IU/L, 1500 IU/L and 2000 IU/L) were evaluated for predicting ectopic pregnancy in this PUL population.

RESULTS

A total of 5544 consecutive women presented to the early pregnancy unit between 25 June 2001 and 14 April 2003. Of these, 569 (10.3%) women were classified as having a PUL, 42 of which were lost to follow up. Of the 527 (9.5%) cases with PUL analyzed, there were 300 (56.9%) failing PULs, 181 (34.3%) IUPs and 46 (8.7%) ectopic pregnancies. Overall, 74.6% were symptomatic and 25.4% were asymptomatic (P = 8.825E-07). The sensitivity and specificity of an hCG level of > 1000 IU/L to detect ectopic pregnancy were 21.7% (10/46) and 87.3% (420/481), respectively; for an hCG level of > 1500 IU/L these values were 15.2% (7/46) and 93.4% (449/481), respectively, and for an hCG level of > 2000 IU/L they were 10.9% (5/46) and 95.2% (458/481), respectively.

CONCLUSIONS

Varying the discriminatory zone does not significantly improve the detection of ectopic pregnancy in a PUL population. A single measurement of serum hCG is not only potentially falsely reassuring but also unhelpful in excluding the presence of an ectopic pregnancy.

Ultrasound features of different histopathological subtypes of borderline ovarian tumors

OBJECTIVE

To describe the gray-scale sonographic and color Doppler imaging features of the most common histopathological subtypes of borderline ovarian tumors.

METHODS

We analyzed retrospectively the preoperative transvaginal sonographic reports of patients with a histological diagnosis of borderline ovarian tumor. All patients were scanned consecutively by two of the investigators using transabdominal and transvaginal gray-scale imaging to assess the morphology and color Doppler to obtain indices of the blood flow. Sonographic findings were compared to histopathological data.

RESULTS

A total of 113 consecutive cases were reviewed from two referral centers for gynecological oncology. At histological examination 50 tumors (44%) were classified as being serous borderline ovarian tumors (SBOT), 61 (54%) were mucinous borderline ovarian tumors (MBOT) (42 intestinal type and 19 endocervical type), and two patients (2%) presented with borderline endometrioid tumors. SBOTs and endocervical-type MBOTs had very similar sonographic features and a smaller diameter, fewer locules (usually unilocular-solid lesions) and a higher color score than intestinal-type MBOTs. Intestinal-type MBOTs were characterized by a significantly higher percentage of lesions with > 10 locules when compared with the endocervical-type MBOTs.

CONCLUSION

Intestinal-type MBOTs have different sonographic features from other common borderline ovarian tumors.

Balancing false positives and false negatives for the detection of differential expression in malignancies

A basic problem of microarray data analysis is to identify genes whose expression is affected by the distinction between malignancies with different properties. These genes are said to be differentially expressed. Differential expression can be detected by selecting the genes with P-values (derived using an appropriate hypothesis test) below a certain rejection level. This selection, however, is not possible without accepting some false positives and negatives since the two sets of P-values, associated with the genes whose expression is and is not affected by the distinction between the different malignancies, overlap. We describe a procedure for the study of differential expression in microarray data based on receiver-operating characteristic curves. This approach can be useful to select a rejection level that balances the number of false positives and negatives and to assess the degree of overlap between the two sets of P-values. Since this degree of overlap characterises the balance that can be reached between the number of false positives and negatives, this quantity can be seen as a quality measure of microarray data with respect to the detection of differential expression. As an example, we apply our method to data sets studying acute leukaemia.

An algorithm including results of gray-scale and power Doppler ultrasound examination to predict endometrial malignancy in women with postmenopausal bleeding

OBJECTIVE

To determine if power Doppler ultrasound examination of the endometrium can contribute to a correct diagnosis of endometrial malignancy in women with postmenopausal bleeding and endometrium > or = 5 mm.

METHODS

Eighty-three women with postmenopausal bleeding and endometrium > or = 5 mm underwent gray-scale and power Doppler ultrasound examination using predetermined, standardized settings. Suspicion of endometrial malignancy at gray-scale ultrasound examination (endometrial morphology) was noted, and the color content of the endometrium at power Doppler examination was estimated subjectively (endometrial color score). Computer analysis of the most vascularized area of the endometrium was done off-line in a standardized manner. Stepwise multivariate logistic regression analysis was carried out to determine which subjective and objective ultrasound and power Doppler variables satisfied the criteria to be included in a model to calculate the probability of endometrial malignancy.

RESULTS

Endometrial thickness, vascularity index (vascularized area/endometrial area), and use of hormone replacement therapy (HRT) satisfied the criteria to be included in the model used to calculate the 'objective probability of endometrial malignancy'. Endometrial morphology, endometrial color score and HRT use satisfied the criteria to be included in the model to calculate the 'subjective probability of malignancy'. Endometrial thickness > or = 10.5 mm had a sensitivity with regard to endometrial cancer of 0.88 and a specificity of 0.61. At a fixed sensitivity of 0.88, the specificity of the 'objective probability of malignancy' (0.81) was superior to all other ultrasound and power Doppler variables (P = 0.001-0.02). The 'objective probability of malignancy' detected more malignancies at endometrium 5-15 mm than endometrial morphology (5/7 vs. 1/7, i.e. 0.71 vs. 0.14; P = 0.125) with a similar specificity (49/57 vs. 51/57, i.e. 0.86 vs. 0.89).

CONCLUSION

Power Doppler ultrasound can contribute to a correct diagnosis of endometrial malignancy, especially if the endometrium measures 5-15 mm. The use of regression models including power Doppler results to estimate the risk of endometrial cancer deserves further development.

Risk assessment for developing type 1 diabetes: intentions of behavioural changes prior to risk notification

BACKGROUND

Recent progress in predictive techniques allows people at risk of developing type 1 diabetes to be identified in a pre-symptomatic stage and prevention trials to be implemented. The present study examined prospectively whether participants in a screening programme anticipated behavioural changes in the event of having a high risk.

METHODS

Four hundred and three first-degree relatives of people with type 1 diabetes completed a self-administered questionnaire about their views on screening and diabetes, and questionnaires on well-being and locus of control.

RESULTS

Prior to risk notification, 73% reported that they intended to introduce lifestyle changes if at high risk. The vast majority of the respondents (87%) reported that eating habits would be the main changes made. Those anticipating changes believed they could take actions to reduce their risk of type 1 diabetes (p<0.001) and to have personal control over diabetes onset (p<0.001). They were also more worried about developing diabetes (p<0.01) and preoccupied with diabetes-related symptoms (p<0.01).

CONCLUSIONS

Prior to risk notification, the process of being screened raised concerns and expectations about future changes. Despite the lack of any evidence, people believed lifestyle changes would be effective in reducing their risk. Since the impact of lifestyle in the development of type 1 diabetes is not yet established, accurate information about the role of health behaviour in the progression to overt diabetes is needed to avoid unrealistic expectations on the benefit of these changes and unnecessary impairment to quality of life. Personally initiated changes should be monitored since they could importantly influence the progress and outcome of prevention trials.

Aging and the pharmacokinetics and metabolism of metoprolol enantiomers in the rat

After i.v. administration of racemic metoprolol in the rat, the plasma concentrations of (R)- and (S)-metoprolol were comparable, and no differences in pharmacokinetic parameters between the two enantiomers were found. From the 3rd to the 12th month, comparable changes were seen for both enantiomers: there was an increase in the area under the plasma concentration-time curve (AUC) and a decrease in blood and plasma clearance. Half-life showed a significant prolongation, volume of distribution decreased between 3 and 12 months and increased between 12 and 24 months. After oral administration of the racemate, AUC and Cmax (maximum plasma concentration) were slightly higher, while oral clearance was slightly lower for (R)-metoprolol than for (S)-metoprolol. With aging, Cmax and AUC increased for both enantiomers, while oral clearance decreased. The change in oral clearance as a function of age is different between (S)- and (R)-metoprolol, and thus enantioselective. In vitro disappearance rate in 3-month-old rats was significantly higher for (S)-metoprolol than for (R)-metoprolol, although the difference was small. With aging, the disappearance rates of both enantiomers increased significantly, but not enantioselectively.

Stereoselective pharmacokinetics of atenolol in the rat: influence of aging and of renal failure

The pharmacokinetics of R- and S-atenolol after intravenous administration of racemic atenolol were studied in 3-, 12- and 24-month-old rats and in 3-month-old rats with renal failure induced by uranyl nitrate. In all age groups, the area under the plasma concentration-time curves is higher for R- than for S-atenolol; volume of distribution, total clearance and renal clearance are lower for R-atenolol than for S-atenolol, but the differences are small. In function of age there is for both enantiomers a significant increase in AUC, due, at least in part, to a decreased renal clearance; the effect of aging is not stereoselective. In rats with renal failure, the AUC of both enantiomers increases, due mainly to a decrease in renal clearance, but to a lesser degree also to a decrease in nonrenal clearance. For both enantiomers, the volume of distribution decreases and the half-life increases in the uraemic rats. The total amount of both enantiomers excreted in the urine is decreased in the rats with renal failure. There are no stereoselective effects of treatment of the rats with uranyl nitrate.

Influence of age on stereoselective pharmacokinetics and metabolism of hexobarbital in the rat

The influence of age on stereoselective pharmacokinetics and in vitro metabolism of R- and S-hexobarbital was studied in the rat. After intravenous administration of the racemate, the plasma concentrations of S-hexobarbital are markedly lower than those of R-hexobarbital. For S-hexobarbital the half-life is somewhat shorter and the volume of distribution and plasma clearance is higher than for its antipode. For both enantiomers an increase in AUC and half-life, and a decrease in clearance are observed with aging. These changes occur mainly between the 3rd and the 12th month and are slightly more pronounced for R- than for S-hexobarbital, as appears from the S/R ratios. The volume of distribution shows no changes with aging. In vitro disappearance rate in 3-month-old rats is significantly higher for S- than for R-hexobarbital. There is for both enantiomers an increase in disappearance rate in 12-month-old rats as compared to younger or older rats, but this is significant only for the R-enantiomer. There are pronounced differences in the kinetics and metabolism of both hexobarbital enantiomers; changes with aging occur, but are only slightly and not always significantly more important for R- than for S-hexobarbital.

Influence of lignocaine on plasma protein binding and pharmacokinetics of verapamil in dogs

The effect of lignocaine (lidocaine) on the plasma protein binding of verapamil has been studied in-vitro and in-vivo in dogs. The binding of verapamil was ca 85%. In-vitro addition of lignocaine at therapeutic concentrations displaced verapamil from its plasma binding sites. Lignocaine in this regard was equipotent with tris(2-butoxyethyl)phosphate, suggesting an interaction at the level of alpha 1-acid glycoprotein binding sites. On in-vivo administration of 4 mg kg-1 in a bolus to dogs in which steady state concentrations of verapamil were present, the free fraction of verapamil increased transiently. During the lignocaine maintenance infusion, it then decreased to a level higher than that before administration of the local anaesthetic. The free verapamil concentrations increased suddenly upon the administration of the lignocaine loading dose, and then returned to values slightly higher than those before lignocaine. After a bolus injection of verapamil during a lignocaine infusion, the verapamil total plasma concentrations were lower than during a saline infusion, but the free concentrations were not different. The volume of distribution of verapamil was increased, whereas the blood clearance had not changed; the lignocaine infusion did not change the hepatic blood flow, as measured by indocyanine green clearance. These results show that lignocaine displaces verapamil in-vitro and in-vivo from its plasma protein binding sites, but the ensuing pharmacokinetic changes do not lead to significant changes in free verapamil concentrations.

Alteration of the pharmacokinetics and metabolism of propranolol and antipyrine elicited by indwelling catheters in the rat

It has been shown that catheter implantation in rats increases concentrations of propranolol and this is usually explained by the increased serum protein binding of propranolol, as a consequence of the higher serum alpha-1-acid glycoprotein concentration. We investigated in this study whether this increase in propranolol concentration after p.o. administration is not also due to a decreased first pass metabolism. We therefore studied in rats the pharmacokinetics and the in vitro metabolism by hepatocytes, of propranolol and antipyrine, 2 and 48 hr after catheter implantation. After p.o. administration of propranolol, the area under the serum concentration time curve 48 hr after catheter implantation was increased 4-fold as compared to 2 hr. As the unbound propranolol fraction was decreased only by a factor of two, it can be concluded that the hepatic intrinsic clearance was decreased, and this was confirmed by a decreased metabolizing activity in the isolated hepatocytes of these animals. After i.v. administration of antipyrine, the systemic clearance was decreased, the volume of distribution was unchanged and the half-life was increased 48 hr after catheter implantation. As antipyrine is a low extraction drug and is not bound to serum proteins, the decreased systemic clearance suggests a lower hepatic intrinsic clearance, and this was again confirmed by a decreased metabolizing activity in the isolated hepatocytes. These results confirm the important effect of the presence of indwelling catheters on the serum concentrations of antipyrine and propranolol, and suggest that this effect is the result of both an increased serum binding and a decreased hepatic metabolism.

The effect of colchicine treatment on the buoyant density of noradrenaline storage particles in the rabbit superior cervical ganglion

The subcellular distribution of noradrenaline (NA) was studied in the rabbit superior cervical ganglion before and after colchicine treatment. One-third of the total NA could be sedimented with the microsomal material in control conditions. Upon colchicine treatment the percentage of the NA which was particle-bound increased only slightly. The absolute NA content of the superior cervical ganglion from colchicine-treated rabbits, however, showed a 3.5-fold increase compared to control animals. Density gradient centrifugation of the microsomal fraction revealed that the distribution of the NA-containing particles changed significantly. Before colchicine treatment the NA was found in a broad band covering the gradient fractions where 'light' and 'heavy' NA vesicles were expected to equilibrate. After colchicine treatment the NA was concentrated in the 'heavy' NA vesicles part of the gradient. The dopamine beta-hydroxylase activity and the NA content in the gradient are increased 3 times after colchicine treatment. These experimental results can be explained by the axoplasmic transport impairing action of colchicine. The neuronal cell body accumulates 'heavy' NA vesicles formed there, unable to transport them towards the periphery.

The presence of dopamine β-hydroxylase in the cerebrospinal fluid of rabbits and its increased concentration after stimulation of peripheral nerves and cold stress

The presence of dopamine beta-hydroxylase activity in the cerebrospinal fluid of rabbits has been shown using a sensitive radiochemical assay; the identity of the reaction product was confirmed by using thin layer chromatographic techniques. The enzyme found in this fluid has some properties (sedimentation and electrophoretic migration) in common with the best characterized preparation of dopamine beta-hydroxylase, that prepared from bovine adrenal chromaffin granules. It also has these properties in common with the enzyme present in the high-speed supernatants obtained from osmotically disrupted synaptosomes prepared from rabbit brain. When the sciatic nerves of rabbits under urethane anaesthesia were stimulated, or when shaved rabbits were subjected to cold stress, the level of dopamine beta-hydroxylase in the cerebrospinal fluid increased. The increase in response to nerve stimulation was gradual, starting within 90 min of stimulation and remained high for at least 3 h after the stimulation had ended, at which time it was 280% of the normal value. There was no equivalent increase in the protein concentration of the cerebrospinal fluid nor was there a change in the enzyme activity when sciatic nerves were exposed but not stimulated. The enzyme present in the cerebrospinal fluid during this period of high activity is identical in its sedimentation and electrophoretic properties to that present in normal fluid. It is suggested that the dopamine beta-hydroxylase activity in cerebrospinal fluid may be derived from noradrenergic neurons within the brain and that the enzyme is released together with noradrenaline.