Simultaneous determination of tryptophan and its 5-hydroxy metabolites in human cerebrospinal fluid by reversed phase liquid chromatography with electrochemical detection

A sensitive ion-pair reversed phase liquid chromatographic method for determining tryptophan, 5-hydroxytryptophan, 5-hydroxytryptamine (serotonin) and 5-hydroxyindole acetic acid has been developed. To separate these indoles in cerebrospinal fluid both octadecyl- and phenyl-bonded columns were tested. The effect of an ion-pair reagent (n-heptyl sulphonate) and pH of the mobile phase on the separation was examined. With the method described the concentrations of the four indoles can be determined within 45 min without sample pretreatment. The sensitivity obtained with electrochemical detection is 0.45 mumol/l for tryptophan and 2-4 nmol/l for 5-hydroxyindoles in human cerebrospinal fluid samples.     

Diffusion and perfusion-weighted magnetic resonance imaging techniques in stroke recovery

Most of the functional recovery after stroke takes place during the first three months after the insult. The neuronal mechanisms underlying this recovery are presently mostly unknown. However, in order to create efficient rehabilitation programs, it is of great importance to uncover these mechanisms. Multiple imaging techniques have been employed for the detection and characterization of ischemic lesions in the brain as well as monitoring of processes associated with stroke recovery. Diffusion and perfusion-weighted magnetic resonance imaging techniques are easy and fast to perform and provide significant information about the ischemic lesion and the hypoperfusion surrounding the lesion at both micro and macrovascular level. More sensitive detection and accurate characterization of the lesion will help in choosing the therapeutic strategies. Methods for monitoring brain function recovery will provide a better understanding of the basic mechanisms of plasticity in the brain, and will serve as a tool for the evaluation of therapeutic interventions, which may eventually include, for example, stem cell transplantation. With the help of these diagnostic tools it may become possible to tailor individual rehabilitation programs.     

Dietary fat predicts coronary heart disease events in subjects with type 2 diabetes

OBJECTIVE: To investigate whether quantity or quality of dietary fat predicts coronary heart disease (CHD) events in middle-aged type 2 diabetic subjects. RESEARCH DESIGN AND METHODS: The dietary habits of 366 type 2 diabetic men and 295 women, aged 45-64 years and free from CHD, were assessed with a 53-item food frequency questionnaire. They were followed up for 7 years. RESULTS: Men in the highest tertile of the polyunsaturated/saturated fat (P/S) ratio (>0.28) had a significantly lower risk for CHD death than men in the two lowest tertiles (5.0 vs. 14.2%, P = 0.009). The risk for all CHD events was 14.2 vs. 23.2%, respectively (P = 0.044). P/S ratio did not predict CHD events in women. In Cox multiple regression analyses taking into account other cardiovascular risk factors, the highest P/S ratio tertile was associated with the lowest rate of CHD death in men (P = 0.048). CONCLUSIONS: Low P/S ratio in men predicted future CHD events in type 2 diabetic subjects independently of conventional CHD risk factors.     

Prevalence of diabetes and impaired glucose tolerance in elderly subjects and their association with obesity and family history of diabetes

The goal of this study was to investigate the prevalence of impaired glucose tolerance (IGT) and non-insulin-dependent diabetes mellitus (NIDDM) in elderly subjects and their association with obesity, central obesity, and a family history of diabetes. A representative population sample of 1300 subjects (471 men, 829 women) aged 65-74 yr participated in the study. The participation rate was 71%. The prevalence rates of previously and newly diagnosed NIDDM and IGT, based on a history of diabetes and an oral glucose tolerance test, were 8.7, 7.0, and 17.8% in men and 11.7, 7.1, and 19.1% in women. Thus, 33.8% of men and 37.9% of women had abnormal glucose tolerance according to World Health Organization criteria. Obesity (body mass index greater than or equal to 27 kg/m2 in men and greater than or equal to 25 kg/m2 in women) and central obesity (waist-hip ratio greater than or equal to 0.98 in men and greater than or equal to 0.89 in women) doubled the prevalence of IGT or NIDDM. The combination of obesity and a family history of diabetes was associated with a more marked increase in the prevalence of IGT or NIDDM in men than in women. Simultaneous presence of obesity, central obesity, and a family history of diabetes was associated with a threefold increase in the prevalence of IGT or NIDDM (65.4 vs. 24.1% in men, 52.8 vs. 19.6% in women, P less than 0.001). The major risk factors for NIDDM, e.g., obesity, central fat distribution, and a family history of diabetes, explained 10% of the variance in 2-h glucose values in multiple regression analysis. In conclusion, the prevalence of IGT and NIDDM was high in elderly subjects. Although obesity, central fat distribution, and a family history of diabetes were significantly associated with the increased prevalence of IGT or NIDDM, they explained only a minor proportion of the variance in 2-h glucose values.     

Aldose reductase gene polymorphisms and peripheral nerve function in patients with type 2 diabetes

OBJECTIVE: We screened the human aldose reductase (ALR) gene for DNA sequence variants in type 2 diabetic and nondiabetic subjects and investigated whether the previously reported and novel polymorphisms were associated with neurophysiologic deterioration and clinical peripheral neuropathy. RESEARCH DESIGN AND METHODS: The study population included 85 Finnish type 2 diabetic and 126 nondiabetic subjects. The genetic analyses were performed using the PCR, single-strand conformation polymorphism, restriction fragment-length polymorphism, and automated laser fluorescence scanning analyses. A detailed neurologic examination and neurophysiologic analyses were performed at the time of diagnosis and at the 10-year examination. RESULTS: The genetic screening identified four polymorphisms: C-106T, C-11G, A11370G, and C19739A. The C and Z-2 alleles of the C-106T polymorphism and the previously reported (CA)(n) repeat marker were more frequent in type 2 diabetic subjects than in nondiabetic subjects. At baseline, the diabetic subjects with the T allele of the C-106T polymorphism had lower sensory response amplitude values in the peroneal (P = 0.025), sural (P = 0.007), and radial (P = 0.057) nerves and, during follow-up, a greater decrease in the conduction velocity of the motor peroneal nerve than those with the C-106C genotype. No associations were found between the polymorphisms examined and clinical polyneuropathy. CONCLUSIONS: The C-106T polymorphism of the ALR gene may contribute to an early development of neurophysiologic deterioration in type 2 diabetic patients.     

Olfactory identification in non-demented elderly population and in mild cognitive impairment: a comparison of performance in clinical odor identification versus Boston Naming Test

Performance in olfactory identification was studied in mild cognitive impairment (MCI), using slightly expanded standard clinical approach to study the olfactory nerve. Four hundred and eighty-six cognitively normal individuals and 72 individuals with MCI underwent spontaneous and cued odor identification and delayed odor recall. Performance in these was compared with the performance in the CERAD version of the Boston Naming Test (BNT). The individuals with MCI scores significantly worse in all tests compared with controls, but the performance in tests assessing odor were less impaired than performance in the BNT. Standard assessment of olfactory nerve function is not sufficient to study cognitive impairment in MCI.     

A Novel Organotypic Model Mimics the Tumor Microenvironment

Carcinoma cell invasion is traditionally studied in three-dimensional organotypic models composed of type I collagen and fibroblasts. However, carcinoma cell behavior is affected by the various cell types and the extracellular matrix (ECM) in the tumor microenvironment. In this study, a novel organotypic model based on human uterine leiomyoma tissue was established and characterized to create a more authentic environment for carcinoma cells. Human tongue squamous cell carcinoma cells (HSC-3) were cultured on top of either collagen or myoma. Organotypic sections were examined by immunohistochemistry and in situ hybridization. The maximal invasion depth of HSC-3 cells was markedly increased in myomas compared with collagen. In myomas, various cell types and ECM components were present, and the HSC-3 cells only expressed ECM molecules in the myoma model. Organotypic media were analyzed by radioimmunoassay, zymography, or Western blotting. During carcinoma cell invasion, matrix metalloprotease-9 production and collagen degradation were enhanced particularly in the myoma model. To evaluate the general applicability of the myoma model, several oral carcinoma, breast carcinoma, and melanoma cell lines were cultured on myomas and found to invade in highly distinct patterns. We conclude that myoma tissue mimics the native tumor microenvironment better than previous organotypic models and possibly enhances epithelial-to-mesenchymal transition. Thus, the myoma model provides a promising tool for analyzing the behavior of carcinoma cells.Tumor growth and invasion are not just determined by the malignant tumor cells, but instead various cell types and the extracellular matrix (ECM) of the tumor microenvironment affect the outcome.¹ Particularly, fibroblasts have many prominent roles in the cancer progression. In fact, in many carcinomas, the majority of the stromal cells are fibroblasts that possess myofibroblastic characteristics and are called cancer-associated fibroblasts. They produce ECM molecules, proteases, growth factors, and chemokines that crucially affect the carcinoma cell behavior.^2,3 In this context, the organotypic three-dimensional skin model developed by Fusenig et al⁴ replicates the in vivo situation more closely in vitro than the two-dimensional cell culture experiments. The model allows studying of carcinoma cell invasion in three-dimensional collagen gel embedded with fibroblasts. The degree of invasion can also be quantitatively analyzed.^5,6 However, this kind of organotypic model remains somewhat artificial due to the lack of other cell types besides fibroblasts and ECM components that are present in vivo. In addition to the carcinoma cells and fibroblasts, endothelial and inflammatory cells, as well as several ECM molecules, are known to contribute to the tumor growth. The induction of angiogenesis, recruitment of inflammatory cells, and increased turnover of ECM components result in tumor progression.^7,8 Therefore, we wished to determine whether real human tissue can be used in the organotypic method to provide a more natural stroma-like environment for studying carcinoma cell invasion. We used uterine leiomyoma tissue, which mainly consists of smooth muscle actin (SMA)-positive cells and collagens.⁹ The existence of various additional cell types and proteins in the myoma tissue was characterized, and the invasiveness of malignant human tongue squamous cell carcinoma cells (HSC-3) into this novel myoma organotypic culture was measured by different methods and compared with the traditional collagen organotypic model. To test the general applicability of the myoma model, the invasion patterns of various cell lines were examined in myoma and collagen organotypic cultures.