Colour Doppler flow in normal axillary lymph nodes

81 women with carcinoma of the breast who underwent axillary nodal dissection were studied pre-operatively with colour Doppler ultrasound. The presence of colour Doppler flow was demonstrated in 83.6% of normal lymph nodes compared with 87.5% of metastatic lymph nodes. Using the presence of colour Doppler signal as the sole diagnostic criterion for the diagnosis of metastasis gave a sensitivity of 92.5%, specificity of 9.52%, accuracy of 50%, positive predictive value of 49.3% and negative predictive value of 57.1%. Using grey scale sonographic criteria, where a metastatic node was defined as a node with loss of central fatty hilum and/or eccentric cortical hypertrophy, a sensitivity of 79.5%, specificity of 94.0%, accuracy of 87.6%, positive predictive value of 91.2% and negative predictive value of 85.5% were obtained. Colour Doppler studies of the axillary nodes in a second group of 106 women who attended for breast cancer screening and had no significant breast or axillary pathology also showed colour Doppler signal in 86.7% of nodes. It is concluded that colour Doppler flow signals can be demonstrated in both normal and metastatic axillary lymph nodes, and is highly non-specific when used as the sole diagnostic criterion in the diagnosis of malignancy.     

Crystal structure of farnesyl protein transferase complexed with a CaaX peptide and farnesyl diphosphate analogue

The crystallographic structure of acetyl-Cys-Val-Ile-selenoMet-COOH and alpha-hydroxyfarnesylphosphonic acid (alphaHFP) complexed with rat farnesyl protein transferase (FPT) (space group P61, a = b = 174. 13 A, c = 69.71 A, alpha = beta = 90 degrees, gamma = 120 degrees, Rfactor = 21.8%, Rfree = 29.2%, 2.5 A resolution) is reported. In the ternary complex, the bound substrates are within van der Waals contact of each other and the FPT enzyme. alphaHFP binds in an extended conformation in the active-site cavity where positively charged side chains and solvent molecules interact with the phosphate moiety and aromatic side chains pack adjacent to the isoprenoid chain. The backbone of the bound CaaX peptide adopts an extended conformation, and the side chains interact with both FPT and alphaHFP. The cysteine sulfur of the bound peptide coordinates the active-site zinc. Overall, peptide binding and recognition appear to be dominated by side-chain interactions. Comparison of the structures of the ternary complex and unliganded FPT [Park, H., Boduluri, S., Moomaw, J., Casey, P., and Beese, L. (1997) Science 275, 1800-1804] shows that major rearrangements of several active site side chains occur upon substrate binding.     

Ultrasound assessment of swallowing in malnourished disabled children

Oral motor dysfunction is common in children with neurological impairment. Nutritional advice depends upon an accurate assessment of feeding potential in these cases. Videofluoroscopic assessment of oral motor function has been the accepted "gold standard" investigation for several years but has significant drawbacks, including the time constraints set by the use of ionizing radiation and the problems posed by the cumbersome equipment needed in mimicking the child's normal feeding situation. Ultrasonography (US) has been suggested as an alternative or additional investigation of oral motor function in children with neurological impairment. We prospectively evaluated a scoring system derived from US assessment of oral motor function in 32 malnourished disabled children with feeding problems by comparing them with a group of matched control children without neurological impairment. US imaging provided useful information with regard to the oral cavity and the soft tissue structures, capturing the salient features of tongue/hyoid/palate activity and bolus transport across the tongue and through the hypopharyngeal area. The mean percentage score obtained by US assessment of oral motor function in children with neurological impairment was 54.3 +/- 23.2 and from children without neurological impairment 91.9 +/- 12.7 (p < 0.0001). Scores for the oral and pharyngeal phases of swallowing were also very significantly lower than that in the control group, both phases being equally impaired in the disabled children. This study has demonstrated that a scoring system based on US assessment of different components of oral motor activity detects statistically significant differences in the feeding capabilities of children with neurological impairment.     

Biphasic cellular repair and implications for multiple field radiotherapy treatments

Data describing the response of several normal tissues to fractionated irradiation, in terms of a biphasic repair of sub-lethal damage, have now been published. Typical results of such analyses have been taken and applied to a conventional radiotherapy protocol of 60 Gy in 30 daily fractions. The effect of using a four field treatment plan is shown to reduce the biological effect of the radiation schedule by increments dependent upon the time interval between each field in a treatment fraction, with a 10% reduction in the extrapolated dose response (ERD) resulting from a 5 min interfield interval. When applied to tissues having the same repair characteristics as pig skin this reduction in ERD is predicted to result in an approximately 25% reduction in the probability of acute morbidity from a protocol of 60 Gy in 30 fractions. These results imply that the basic LQ model, which is unable to correct for interfield intervals, overestimates the effect on normal tissues of radical clinical protocols, most of which use more than a single field. Increasing the interfield interval could be used to reduce the normal tissue side effects from radical radiotherapy when multiple fields are used.     

Dexmedetomidine and halothane produce similar alterations in electroencephalographic and electromyographic activity in cats

Hydroxylated polychlorinated biphenyls also known as biphenylols, are suspected estrogen mimics found in the environment. Various derivatization schemes were evaluated and a gas chromatography-ion trap mass spectrometry method was developed for the trifluoroacetyl derivative using MS-MS techniques for the analysis of eleven biphenylols. A time-segmented chromatographic method was developed using the respective MS-MS parameters to analyze all the eleven biphenylols in a single chromatographic run. Isomers were differentiated based on the MS-MS data of the trofluoroacetyl-biphenylol derivatives. The method was applied to detect 40 pg on-column of these compounds in a spiked egg sample which simulates a real world sample.     

Cloning of Rab GTPases expressed in human skeletal muscle: studies in insulin-resistant subjects

To explore the potential role of Rab GTPases in human insulin resistance, we first employed a PCR-cloning approach to identify Rab isoforms that are expressed in human skeletal muscle. Multiple Rab isoforms including Rab1A, Rab4A, Rab5B, Rab7, Rab8, Rab10, Rab12A, Rab13, Rab18, Rab21, and Rab22 mRNA were found to be expressed in human skeletal muscle. The second goal was to examine whether mRNA expression for Rabs targeted to endocytotic/exocytotic compartments was altered as a function of insulin resistance. Quantitative PCR analysis demonstrated that Rab4A, Rab5B and Rab18 mRNA levels in skeletal muscle from insulin-resistant patients without (IR) and with non-insulin-dependent diabetes mellitus (NIDDM) were not significantly different from those in insulin-sensitive controls (IS). At the protein level, total Rab5B amount was not significantly different among IS, IR and NIDDM subgroups. However, in basal muscle, Rab5B in the total membrane fraction was 2.1-3.6 fold higher in IR and NIDDM than in IS subjects. Insulin increased membrane-associated Rab5B by 3-fold in IS subjects, whereas this effect was not significant in both IR and NIDDM subgroups. Thus, for the first time, we have comprehensively studied the mRNA expression of Rab isoforms in human muscle. The phlethora of Rab GTPases are indicative of high volume of vesicular traffic and regulated metabolism. The potential role of specific Rab isoforms in insulin resistance does not rely on a change in steady state mRNA levels, but is demonstrable as an alteration in protein subcellular distribution and trafficking.     

An autosomal genomic scan for loci linked to prediabetic phenotypes in Pima Indians

Type 2 diabetes mellitus is a common chronic disease that is thought to have a substantial genetic basis. Identification of the genes responsible has been hampered by the complex nature of the syndrome. Abnormalities in insulin secretion and insulin action predict the development of type 2 diabetes and are, themselves, highly heritable traits. Since fewer genes may contribute to these precursors of type 2 diabetes than to the overall syndrome, such genes may be easier to identify. We, therefore, undertook an autosomal genomic scan to identify loci linked to prediabetic traits in Pima Indians, a population with a high prevalence of type 2 diabetes. 363 nondiabetic Pima Indians were genotyped at 516 polymorphic microsatellite markers on all 22 autosomes. Linkage analyses were performed using three methods (single-marker, nonparametric multipoint [MAPMAKER/SIBS], and variance components multipoint). These analyses provided evidence for linkage at several chromosomal regions, including 3q21-24 linked to fasting plasma insulin concentration and in vivo insulin action, 4p15-q12 linked to fasting plasma insulin concentration, 9q21 linked to 2-h insulin concentration during oral glucose tolerance testing, and 22q12-13 linked to fasting plasma glucose concentration. These results suggest loci that may harbor genes contributing to type 2 diabetes in Pima Indians. None of the linkages exceeded a LOD score of 3.6 (a 5% probability of occurring in a genome-wide scan). These findings must, therefore, be considered tentative until extended in this population or replicated in others.     

Effect of cAMP-induced transcription on the repair of the phosphoenolpyruvate carboxykinase gene by hepatocytes isolated from young and old rats

Animal experiments suggest that the fetal brain is sensitive to nicotine. Although much attention has been given to the relation between cigarette smoking during pregnancy and neurodevelopment in children, this remains controversial. Our study describes the relationship between maternal cigarette smoking during pregnancy and babbling abilities of the 8-month-old infant. In a longitudinal cohort, information was collected at the 16th week of gestation, at delivery and when the infant was about 8 months old. At this age babbling abilities of the infant were evaluated by a health visitor during a home visit. Singleton infants without any disability born at Aarhus University Hospital, Denmark, 1991-92 and still living in the Community of Aarhus at the age of 8 months were eligible (n = 2302). Complete follow-up was obtained for 1871 children (81.3%). A dose-response-like relationship between number of cigarettes smoked per day during pregnancy and babbling abilities was found after controlling for potential confounders. Smoking 10 or more cigarettes per day during pregnancy almost doubled the risk (odds ratio [OR] = 2.0, 95% confidence interval [CI] 1.1-3.6) of the infant being a non-babbler at the examination at 8 months. Among children who were breast fed for less than 4 months this risk was even higher (OR = 2.7, CI 1.3-5.8).     

Muscle Rad expression and human metabolism: potential role of the novel Ras-related GTPase in energy expenditure and body composition

Ras associated with diabetes (Rad), a new ras-related GTPase, was recently identified by subtractive cloning as an mRNA in skeletal muscle that is overexpressed in NIDDM. To better understand its metabolic significance, we measured skeletal muscle Rad expression in well-characterized insulin sensitive (IS) and insulin resistant (IR) subjects with normal glucose tolerance and in untreated NIDDM patients. We found no differences in expression of Rad mRNA levels among IS, IR, and NIDDM groups using a ribonuclease protection assay (0.22 +/- 0.06, 0.13 +/- 0.01, and 0.16 +/- 0.02 relative units, respectively; NS) and no differences in Rad protein expression using a specific anti-peptide Rad antibody (1.05 +/- 0.18, 1.14 +/- 0.08, and 1.08 +/- 0.21 units/mg protein, respectively; NS). However, Rad protein levels were positively correlated with BMI (r = 0.43, P = 0.03) and percentage body fat (r = 0.55, P < 0.005), two independent measures of obesity, and negatively correlated with resting metabolic rate (r = 0.49, P = 0.01). In multiple regression analyses, percentage body fat and resting metabolic rate independently accounted for 30 and 10% of individual variability in muscle Rad protein expression. In conclusion, Rad expression in skeletal muscle is not altered as a function of insulin resistance or NIDDM in humans. However, these data, for the first time, implicate a role for Rad in regulating body composition and energy expenditure and provide a framework for studies designed to elucidate Rad's cellular functions.