Gross deletions of the neurofibromatosis type 1 (NF1) gene are predominantly of maternal origin and commonly associated with a learning disability, dysmorphic features and developmental delay

The adherence of either cholera toxin or the heat-labile enterotoxin of Escherichia coli to monosialoganglioside gal(beta1-3)galNAc(beta1-4)[sialic acid (alpha2-3)]gal(beta1-4)glc(beta)1-ceramide (GM1) present on the surface of epithelial cells lining the intestine is the first step of a series that results in the induction of a watery diarrhea. While cholera is more severe, both can lead to death as a result of dehydration. To determine the potential of defined multivalent oligosaccharides, synthesized by the covalent attachment of multiple phenylisothiocyanate (PITC) derivatives of gal(beta1-3)galNAc(beta1-4)[sialic acid(alpha2-3)]gal(beta1-4)glc (oligo-GM1) to the arms of a poly(propylene imine) dendrimer, as therapeutic agents for these diseases, their ability to inhibit adherence of the toxins to cell surface-associated GM1 was determined. They not only inhibited choleragenoid (binding subunit of cholera toxin) binding to GM1-treated NCTC-2071 cells (chemically transformed murine fibroblasts) at 5 degrees, but also inhibited adherence of the choleragenoid, cholera toxin, and heat-labile enterotoxin of E. coli to GM1-treated NCTC-2071 cells at 37 degrees. Inhibition was observed whether the toxin was preincubated with the oligo-GM1-PITC-derivatized dendrimer prior to addition to cells or given just after the addition of the derivatized dendrimer to cells. The derivatized dendrimer had no effect on cell viability, as monitored by trypan blue exclusion. Blue-shifts in tryptophan fluorescence emission spectra maxima induced by adherence of either choleragenoid, cholera holotoxin, or the heat-labile enterotoxin of E. coli to oligo-GM1-PITC-derivatized dendrimers were similar to those induced by adherence to GM1 or oligo-GM1. Comparable shifts were not observed when the toxins were incubated with gangliosides that fail to function as receptors.     

Ligand partitioning into membranes: its significance in determining Km and Ks values for cytochrome P-450 and other membrane bound receptors and enzymes

Enzyme(s) capable of decomposing N-acetylglucosaminyl ribitol teichoic acid prepared from the cell wall of Staphylococcus aureus FDA 209 P was obtained from the culture supernatant of a gram-negative, rod-shaped, spore-forming soil bacterium. Properties of the bacterium were very similar to those of Bacillus circulans.     

Evaluation of an adenosine 5'-triphosphate assay as a screening method to detect significant bacteriuria

The bioluminescent reaction of adenosine 5'-triphosphate (ATP) with luciferin and luciferase has been used in conjunction with a sensitive photometer (Lab-Line's ATP photometer) to detect significant bacteriuria in urine. This rapid method of screening urine specimens for bacteriuria was evaluated by using 348 urine specimens submitted to the clinical microbiology laboratory at the University of Minnesota Hospitals for routine culture using the calibrated loop-streak plate method. There was 89.4% agreement between the culture method and the ATP assay, with 7.0% false positive and 27.0% false negative results from the ATP assay using 10(5) organisms/ml of urine or greater as positive for significant bacteriuria and less than 10(5) organisms/ml as negative for significant bacteriuria.     

Gas-chromatographic analysis for therapeutic concentration of imipramine and disipramine in plasma, with use of a nitrogen detector

We describe a method for the simultaneous gas-chromatographic analysis of imipramine and desipramine (the active N-desmethyl metabolite) at therapeutic concentrations in human plasma, with use of a nitrogen detector. Imipramine is measured as the unchanged base and desipramine as its N-tribluoroacetyl derivative. Promazine is the internal standard. The lower limit of sensitivity is 5 mug/liter for each drug, and the within-day coefficients of variation for the determination of imipramine and desipramine, respectively, are 6.0% and 3.3%. We measured concentrations of these drugs both in patients receiving therapeutic doses of imipramine and in those who had ingested an overdose.     

Middle-ear impedance measurements in screening

Middle-ear disorders are the major cause of hearing loss in the young school child, the majority of sensorineural disorders already having been detected. Mild conductive deafness may lead to educational retardation, psychological and social problems as well as to more severe middle-ear problems. It is consequently important to detect persistent middle-ear conditions as early as possible. Pure-tone audiometry has been shown to be a poor method of identifying middle-ear effusions. Impedance measurement is considerably more efficient, and different approaches are reviewed in the light of long-term studies of middle-ear effusion.     

Clinical evaluation of mastalgia

OBJECTIVE: To describe an accurate and reproducible method to quantify a patient's subjective experience of breast pain. DESIGN: Prospective diary study. SETTING: Military tertiary care hospital. PATIENTS: Thirty female military health care beneficiaries from the Walter Reed Army Medical Center, Washington, DC, gynecology and general surgery clinics. MAIN OUTCOME MEASURES: Daily mastalgia was recorded using a visual analog scale and menstrual symptoms were measured using a daily questionnaire. These measures were correlated with results of a screening questionnaire completed prior to study entry. RESULTS: Patients identified as having cyclical mastalgia based on the screening questionnaire (n= 15) were found to have higher peak perimenstrual mastalgia according to their daily diaries than patients who did not meet diagnostic criteria (n=15) (5.3+/-0.7 vs 3.5+/-0.5, P<.001). Applying the same criteria used in the screening questionnaire to the diary data, 17 of 30 patients met diagnostic criteria for cyclical mastalgia. The ability of the screening questionnaire to predict the results of the prospective diary data was calculated, and positive and negative predictive values were 73% and 60%, respectively. Most patients with cyclical mastalgia also have other perimenstrual psychological and somatic complaints, although a subset of patients has high levels of mastalgia with minimal associated symptoms. CONCLUSIONS: Accurate assessment of mastalgia cannot be done with a retrospective questionnaire and requires prospective diary evaluation, owing to the variable and subjective nature of symptoms and recall bias. A daily visual analog scale provides reproducible results and is easy for patients to use.     

Mitosene-DNA adducts. Characterization of two major DNA monoadducts formed by 1,10-bis(acetoxy)-7-methoxymitosene upon reductive activation

Reductive activation of racemic 1,10-bis(acetoxy)-7-methoxymitosene WV15 in the presence of DNA, followed by enzymatic digestion and HPLC analysis, revealed the formation of various DNA adducts. Reduction is a necessary event for adduct formation to occur. This reductive activation was performed under hypoxic conditions in various ways: (1) chemically, using a 2-fold excess of sodium dithionite (Na2S2O4), (2) enzymatically using NADH-cytochrome c reductase, (3) electrochemically on a mercury pool working electrode, and (4) catalytically, using a H2/PtO2 system. Five different mitosene-DNA adducts were detected. These adducts were also present when poly(dG-dC) was used instead of DNA, but were absent with poly(dA-dT). All were shown to be adducts of guanine. Reduction of 1, 10-dihydroxymitosene WV14 in the presence of DNA did not result in detectable adduct formation, demonstrating the importance of good leaving groups for efficient adduct formation by these mitosenes. Finally, two of the adducts were isolated and their structures elucidated, using mass spectrometry, 1H NMR and circular dichroism (CD). The structures were assigned as the diastereoisomers N2-(1"-n-hydroxymitosen-10"-yl), 2'-deoxyguanosine (n = alpha or beta). These type of adducts, in which the mitosene C-10 is covalently bonded to the N-2 of a guanosylic group, are different from the well-known mitomycin C 2'-deoxyguanosine monoadducts, that is linked via the mitomycin C C-1 position, demonstrating that the order of reactivity of the C-1 and C-10 in these mitosenes is reversed, as compared to mitomycin C. The 7-methoxy substituent of WV15 is a likely factor causing this switch. Evidence is presented that the 7-substituent of mitosenes also influences their DNA alkylation site. Adducts 4 and 5 represent the first isolated and structurally characterized covalent adducts of DNA and a synthetic mitosene.     

Conserved residues amino-terminal of cytoplasmic tyrosines contribute to the SHP-1-mediated inhibitory function of killer cell Ig-like receptors

The heart has been recognized as a major target of thyroid hormone action. Our study investigates both the regulation of cardiac-specific genes and contractile behavior of the heart in the presence of a mutant thyroid hormone receptor beta1 (T3Rbeta1-delta337T) derived from the S kindred. The mutant receptor was originally identified in a patient with generalized resistance to thyroid hormone. Cardiac expression of the mutant receptor was achieved by a transgenic approach in mice. As the genes for myosin heavy chains (MHC alpha and MHC beta) and the cardiac sarcoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA2) are known to be regulated by T3, their cardiac expression was analyzed. The messenger RNA levels for MHC alpha and SERCA2 were markedly down-regulated, MHC beta messenger RNA was up-regulated. Although T3 levels were normal in these animals, this pattern of cardiac gene expression mimics a hypothyroid phenotype. Cardiac muscle contraction was significantly prolonged in papillary muscles from transgenic mice. The electrocardiogram of transgenic mice showed a substantial prolongation of the QRS interval. Changes in cardiac gene expression, cardiac muscle contractility, and electrocardiogram are compatible with a hypothyroid cardiac phenotype despite normal T3 levels, indicating a dominant negative effect of the T3Rbeta mutant.