In vivo (31)P magnetic resonance spectroscopy and morphometric analysis of the perfused vascular architecture of human glioma xenografts in nude mice.

The relationship between the bioenergetic status of human glioma xenografts in nude mice and morphometric parameters of the perfused vascular architecture was studied using (31)P magnetic resonance spectroscopy (MRS), fluorescence microscopy and two-dimensional digital image analysis. Two tumour lines with a different vascular architecture were used for this study. Intervascular distances and non-perfused area fractions varied greatly between tumours of the same line and tumours of different lines. The inorganic phosphate-nucleoside triphosphate (P(i)/NTP) ratio increased rapidly as mean intervascular distances increased from 100 microm to 300 microm. Two morphometric parameters - the percentage of intervascular distances larger than 200 microm (ivd200) and the non-perfused area fraction at a distance larger than 100 microm from a nearest perfused vessel (area100), - were deduced from these experiments and related to the P(i)/NTP ratio of the whole tumour. It is assumed that an aerobic to anaerobic transition influences the bioenergetic status, i.e. the P(i)/NTP ratio increased linearly with the percentage of ivd200 and the area100.     

Magnetic resonance studies on brain dysfunction induced by organic solvents.

A 38-year-old layer of parquet flooring was referred because of memory impairment, tiredness and diffuse headaches. His work involved using several neurotoxic organic solvents. Extensive laboratory, neuropsychological, clinical neurophysiological, neuroadiological, magnetic resonance (MR) imaging and spectroscopy studies were performed. The neuropsychological and behavioural assessments showed an organic brain syndrome. MR imaging and CT scanning of the brain revealed enlarged ventricles and generalized atrophy. 31P and 1H MR spectroscopic measurements did not show any abnormalities. Owing to recent improvements regarding sensitivity and facilitated assignment, MR spectroscopy may provide in the near future significant additional information on brain metabolism in patients with brain dysfunction presumably induced by organic solvents.     

Laser-assisted microdissection and molecular analysis at the cellular level

Developments of molecular biological techniques have allowed the analysis of small tissue samples. In order to obtain optimal results it is essential to work with pure cell populations. The procurement of pure samples has, however, been one of the main limiting factors in biomedical research. Recently developed systems for laser-assisted microdissection now allow the isolation of pure cell populations from tissue sections, even at a single cell level, that are suitable for subsequent molecular analyses. Since morphological features can be directly related to molecular characteristics, studies concerning molecular genetic backgrounds underlying disease can be performed more easily and accurately. By future combined use of laser microdissection and new molecular analysis methods, the applications for laser-micro-dissection will increase further.     

Normal voiding patterns and determinants of increased diurnal and nocturnal voiding frequency in elderly men

PURPOSE: We determined the normal value of diurnal and nocturnal voiding frequency, and its determinants in a population based sample of elderly men. MATERIALS AND METHODS: We collected data on 1,688 men 50 to 78 years old recruited from the population of Krimpen, The Netherlands. Measurements consisted of self-administered questionnaires, including the International Prostate Symptom Score (I-PSS), a 3-day frequency-volume chart, transrectal prostatic ultrasound, uroflowmetry and post-void residual urine volume measurement. RESULTS: Diurnal voiding frequency is independent of age and more frequent in men with benign prostatic hyperplasia (BPH). Nocturia 2 or more times is present in 30% of men 50 to 54 and in 60% of those 70 to 78 years old, while nocturia 3 or more times is present in 4% and 20%, respectively. In addition, nocturia is strongly associated with BPH and nocturnal polyuria but apparently not with cardiovascular symptoms, hypertension or diabetes mellitus. We noted poor agreement of the responses on the frequency-volume charts and the I-PSS question on nocturia. Using the I-PSS leads to a higher prevalence of nocturia. CONCLUSIONS: Diurnal frequency is independent of age (median 5 voids, interquartile range 4 to 6) but higher in men with BPH. Nocturia increases with advancing age and is more frequent in men with nocturnal polyuria. BPH is an independent risk factor for nocturia and increased diurnal voiding frequency. In those with nocturia there is a great difference in subjective symptoms and objective data, indicating that the weight of the I-PSS question on nocturia for making treatment decisions should be reconsidered.     

Estimating treatment effects in randomized clinical trials in the presence of non-compliance

In clinical trials where patients are randomized between two treatment arms, not all patients comply with the treatment they were randomly assigned to. The reasons for (non)compliance may be associated with the outcome variable and thereby act as confounders. The standard way of analysing such trials is by the 'intention-to-treat' principle, which allows the use of permutation tests. Conclusions drawn from such tests do not depend on untested assumptions such as absence of confounding. However, this approach may yield biased estimators for the causal effects of treatments. We consider the estimation of such effects for clinical trials where non-compliers can be considered to have switched to the other trial arm. The most important example of this is the placebo-controlled clinical trial where no substantial placebo effects are anticipated. We consider the situation where the relationship between compliance, and thus treatment received, and outcome is influenced by unobserved confounders. The residual of the regression of the actual treatment indicator variable on the randomization arm indicator variable is shown to 'intercept' the effect of such confounders. Inclusion of this residual in a multivariate analysis, in conjunction with the treatment indicator variable, should thus adjust for confounding. Examples are given. In those examples, the results are similar to those obtained by more complex methods.     

Joint space narrowing and relationship with symptoms and signs in adults consulting for hip pain in primary care

OBJECTIVE: To study whether clinical symptoms and signs can predict radiological osteoarthritis (OA) of the hip in primary care patients with hip pain. METHODS: Consecutive patients (n = 220) aged 50 years or older consulting the general practitioner for hip pain and referred for radiological investigation underwent a standardized history, radiological, laboratory, and physical examination. Radiological OA was confirmed with joint space < or = 2.5 mm. Additionally, a more stringent definition was used (< or = 1.5 mm). The relationship between radiological OA and possible clinical symptoms/signs of OA was tested. Combinations of clinical symptoms/signs that had shown an independent relationship with radiological OA in multivariate analyses were tested for their predictive value. RESULTS: Radiological OA (joint space < or = 2.5 mm) of the (more) symptomatic hip was present in 35.5% of the study population and more severe OA (joint space < or = 1.5 mm) in 11.4%. Presence of 4 specific symptoms/signs from history and examination showed a positive predictive value (PPV) of 73% (specificity 91%, sensitivity 45%) for radiological OA. When 5 specific symptoms/signs were present, the PPV for the more severe radiological OA was 82% (specificity 98%, sensitivity 72%), and when 6 or 7 specific symptoms/signs were present the PPV was 100% (specificity 100%, sensitivity 40% and 8%, respectively). Negative predictive values were high for almost all combinations. CONCLUSION: In primary care patients with hip pain, clinical symptoms and signs can to a moderate extent predict radiological OA and to a large extent more severe radiological OA.     

Presence and localization of T-cell subsets in relation to melanocyte differentiation antigen expression and tumour regression as assessed by immunohistochemistry and molecular analysis of microdissected T cells

Melanoma-associated antigens may be the driving force behind the lymphocytic infiltrates in melanomas and the occurrence of melanoma regression. To investigate the clinical relevance of melanoma differentiation antigens (MDAs) as T-cell targets, the relationship between the presence and localization of T-cell subsets and the expression of MDAs was studied by immunohistochemistry and the diversity of CD8+ T cells in regressive melanomas was assessed using laser-assisted microdissection. While MDA expression as well as T-cell subset distribution, as assessed by immunohistochemical analysis, was heterogeneous within and between lesions, they were histologically independent phenomena. In four lesions studied in detail by PCR analysis of microdissected T cells, a limited T-cell diversity and evidence for clonally expanded tumour infiltrating lymphocytes were found. However, no major differences in T-cell diversity, as assessed by PCR analysis, between peri-and intra-tumoural areas became apparent, this despite the known clinical significance of the specific localization of a T-cell infiltrate. T cells of clonal origin did not show preferential localization to regressive tumour areas. Moreover, clonally related cells were found in two lesions with a non-brisk infiltrate, while in two lesions with a brisk infiltrate (clinically, a good prognostic factor) no evidence for clonally expanded tumour infiltrating lymphocytes was found. These data support the notion that specific immune reactivity and homing of specific cells to the tumour can occur in melanoma patients. However, they also show that the presence of clonally expanded T cells in the tumour is not necessarily associated with an effective anti-tumour immune response and may, for instance, represent regulatory cells. It appears that the clinical impact of an anti-tumour immune response is largely decided at the tumour site, where micro-environmental conditions dictate the functional state of the T cells. Full understanding of these processes can only be achieved by performing more dynamic analyses of the local host-tumour interactions.