Instruments that measure beliefs about cancer from a cultural perspective

Understanding beliefs about cancer from a cultural perspective is of great importance as the population mix of this country continues to shift and change. In order to assess the cancer beliefs held by diverse populations, culturally specific tools are needed. The purpose of this article is to identify and describe instruments that have been used to assess beliefs about cancer. Eight published and unpublished instruments were identified from a review of the literature. These tools address attitudes and beliefs toward cancer, cancer prevention, and cancer treatment within a variety of age groups and ethnic populations. One tool was related to adolescents, whereas the remainder focused on adults; three were translated into other languages; four tools involved questionnaire format and four interview format. Although it is encouraging to report that culturally specific tools are being developed, there is a demonstrated need to increase the expertise in developing such instruments.

Free-living energy expenditure measured by two independent techniques in pregnant and nonpregnant Gambian women

Free-living energy expenditure (EE) was assessed in 37 young pregnant Gambian women at the 12th (n = 11, 53.5 +/- 1.7 kg), 24th (n = 14, 54.7 +/- 2.1 kg), and 36th (n = 12, 65.0 +/- 2.6 kg) wk of pregnancy and was compared with nonpregnant nonlactating (NPNL) control women (n = 12, 50.3 +/- 1.6 kg). The following two methods were used to assess EE: 1) the heart rate (HR) method using individual regression lines (HR vs EE) established at different activity levels in a respiration chamber and 2) the doubly labeled water (2H2(18)O) method in a subgroup of 25 pregnant and 7 control women. With the HR method the EE during the agricultural rainy season was found to be 2,408 +/- 87, 2,293 +/- 122, and 2,782 +/- 130 kcal/day at 12, 24, and 36 wk of gestation and were not significantly different from the control group (2,502 +/- 133 kcal/day). These findings were confirmed by the 2H2(18)O measurements, which failed to show any effect of pregnancy on EE. Expressed per unit body weight, the free-living EE was found to be lower (P less than 0.01 with 2H2(18)O method) at 36 wk of gestation than in the NPNL group. It is concluded that, in these Gambian women, energy-sparing mechanisms that contribute to meet the additional energy stress of gestation are operating during pregnancy (e.g., diminished spontaneous physical activity).

Slit scan flow cytometry of isolated chromosomes following fluorescence hybridization: an approach of online screening for specific chromosomes and chromosome translocations

The recently developed methods of non radioactive in situ hybridization of chromosomes offer new aspects for chromosome analysis. Fluorescent labelling of hybridized chromosomes or chromosomal subregions allows to facilitate considerably the detection of specific chromosomal abnormalities. For many biomedical applications (e.g. biological dosimetry in the low dose range), a fast scoring for aberrations (e.g. dicentrics or translocations) in required. Here, we present an approach depending on fluorescence in situ hybridization of isolated suspension chromosomes that indicates the feasibility of a rapid screening for specific chromosomes or translocations by slit scan flow cytometry. Chromosomes of a Chinese hamster x human hybrid cell line were hybridized in suspension with biotinylated human genomic DNA. This DNA was decorated with FITC by a double antibody system against biotin. For flow cytometry the chromosomes were stabilized with ethanol and counterstained with DAPI or propidium iodide (PI). An experimental data set of several hundred double profiles was obtained by two parameter slit scan flow cytometry and evaluated automatically. The evaluation algorithm developed allowed a classification of chromosomes according to the number of centromeres and their chromosomal positions in less than 1 msec per individual profile. Approximately 20% of the measured DAPI profiles showed a bimodal distribution with a significant centromeric dip indicating a "normal" chromosomal morphology and a correct alignment in the flow system. In many cases, profiles of a "normal" bimodal fluorescence distribution of the DNA stain (DAPI, PI) were correlated with a "normal" FITC profile. Due to their centromeric indices these profiles agreed well to the expected human chromosomes of the cell line. In some cases of "normal" DAPI (PI) profiles, "aberrant" FITC profiles were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkylation of an active-site cysteinyl residue during substrate-dependent inactivation of Escherichia coli S-adenosylmethionine decarboxylase

S-Adenosylmethionine decarboxylase from Escherichia coli is a member of a small class of enzymes that uses a pyruvoyl prosthetic group. The pyruvoyl group is proposed to form a Schiff base with the substrate and then act as an electron sink facilitating decarboxylation. We have previously shown that once every 6000-7000 turnovers the enzyme undergoes an inactivation that results in a transaminated pyruvoyl group and the formation of an acrolein-like species from the methionine moiety. The acrolein then covalently alkylates the enzyme [Anton, D. L., & Kutny, R. (1987) Biochemistry 26, 6444]. After reduction of the alkylated enzyme with NaBH4, a tryptic peptide with the sequence Ala-Asp-Ile-Glu-Val-Ser-Thr-[S-(3-hydroxypropyl)Cys]-Gly-Val-Ile-Ser-Pro - Leu-Lys was isolated. This corresponds to acrolein alkylation of a cysteine residue in the second tryptic peptide from the NH2 terminal of the alpha-subunit [Anton, D. L., & Kutny, R. (1987) J. Biol. Chem. 262, 2817-2822]. The modified residue derived is from Cys-140 of the proenzyme [Tabor, C. W., & Tabor, H. (1987) J. Biol. Chem. 262, 16037-16040] and lies in the only sequence conserved between rat liver and E. coli S-adenosylmethionine decarboxylase [Pajunen et al. (1988) J. Biol. Chem. 263, 17040-17049]. We suggest that the alkylated Cys residue could have a role in the catalytic mechanism.

Effects of dietary supplementation on work performance in Gambian laborers

The effect of food supplementation on productivity of Gambian subsistence farmers was studied during a natural food shortage induced by the annual hungry season. Sixteen men in two groups matched for weight, height, hemoglobin, and physical-work capacity followed a crossover protocol with 6-wk supplementation and control periods. Productivity was assessed over the final 3 wk of each period by quantifying piece-rate-paid road building. Supplementation comprised an ad libitum supply of highly palatable energy-dense food provided three times daily. Outcome variables were total loads transported, loads per working hour, time per load, total energy expenditure assessed by doubly labeled water and heart-rate monitoring, postwork activity, and anthropometry. Body weight decreased during control periods, indicating a real energy deficit, and increased during supplementation in both groups. Supplementation had no significant impact on productivity variables. Energy-deficient men can maintain maximal productivity over short periods if sufficiently motivated but at the expense of body weight.

Chimeric pneumococcal cell wall lytic enzymes reveal important physiological and evolutionary traits

Two novel chimeric pneumococcal cell wall lytic enzymes, named LC7 and CL7, have been constructed by in vitro recombination of the lytA gene encoding the major autolysin (LYTA amidase) of Streptococcus pneumoniae, a choline-dependent enzyme, and the cpl7 gene encoding the CPL7 lysozyme of phage Cp-7, a choline-independent enzyme. In remarkable contrast with previous chimeric constructions, we fused here two genes that lack nucleotide homology. The CL7 enzyme, which contains the N-terminal domain of CPL7 and C-terminal domain of LYTA, exhibited a choline-dependent lysozyme activity. This experimental rearrangement of domains might mimic the process that have generated the choline-dependent CPL1 lysozyme of phage Cp-1 during evolution, providing additional support to the modular theory of protein evolution. The LC7 enzyme, built up by fusion of the N-terminal domain of LYTA and the C-terminal domain of CPL7, exhibited an amidase activity capable of degrading ethanolamine-containing cell walls. The chimeric amidase behaved as an autolytic enzyme when it was cloned and expressed in S. pneumoniae. The chimeric enzymes provided new insights on the mechanisms involved in regulation of the host pneumococcal autolysins and on the participation of these enzymes in the process of cell separation. Furthermore, our experimental approach confirmed the basic role of the C-terminal domains in substrate recognition and revealed the influence of these domains on the optimal pH for catalytic activity.

[Validity of 5 bioelectric impedance equations for the estimation of lean body mass in women]

Fat free mass (FFM) predicted by five bioelectrical impedance (BIA) available formulae (Segal et al., Lukaski et al., Kushner et al., Deurenberg et al., manufacturer's predictive equation) was compared with densitometrically-determined FFM (as a reference method) in two groups of young women with different anthropometric characteristics. In the farmers (very short and light individuals), none of the studied formulae was able to accurately predict FFM: this latter was overestimated in subjects with low and underestimated in those with high FFM. In the other group (INCAP employees), only values predicted by Lukaski formula were in perfect agreement with FFM, showing no bias depending on FFM changes. In conclusion, the available BIA formulae seem to be specific for population from which they were derived and could not be used on samples from other populations if not cross-validated.

Fast processing of black and white films used in the EM lab

Kodak black and white film emulsions 4489, 4162, 2415, TMAX-100, TMAX-400, MPD-4 and RPC-651 can be developed in less than 10 minutes on a film processor, quickly printed on resin coated paper and dried with auto-processor and dryer. Adjustments to the ASA (ISO) to compensate for increased contrast with auto-processing are described.

Evaluation of near infra-red interactance as a method for predicting body composition

The ability of near infra-red interactance (NIRI) to predict body composition, as measured by whole-body densitometry, was assessed in a group of 29 healthy volunteers; 15 m, 14 f, aged 18-40 years, body mass index (BMI) 18.3-28.5 kg/m2. The results were compared with those obtained by five other predictive methods: whole-body impedance/resistance, skinfold thicknesses, and methods based on weight and height or BMI. The correlation between densitometry and the alternative methods, including NIRI, were found to be remarkably similar, both with respect to fat (r = 0.90-0.92, s.e.e. = 2.12-2.47 kg), and fat-free mass (r = 0.96-0.97, s.e.e. = 2.13-2.71 kg). Percentage body fat (densitometry) correlated better with the near infrared measurements made in the biceps area than with those made in the triceps or thigh areas, or with a combination of measurements made at two or three sites. The 95 per cent limits of agreement between NIRI and densitometry for the estimation of body constituents were slightly greater than those between densitometry and the other methods. NIRI was also found to underestimate body fat increasingly as the degree of adiposity increased. This under-estimation was found to be particularly marked (16 per cent body weight) in a small and separate group of grossly obese women, BMI greater than 50 kg/m2, whose body composition was assessed by total body potassium as well as by densitometry. This study suggests that, in the healthy group of subjects examined, NIRI has little or no advantage over other simple methods in predicting body composition measured by classical whole-body densitometry.

Reaction of dibenzalacetone with hydroxylamine hydrochloride under phase-transfer conditions. 1 H and 13 C 2D NMR structural elucidation of the products

The constitution, configuration and conformation of three N-hydroxydiphenylpiperidines were established by ¹ H and ¹³ C 2D NMR spectroscopy. The products were obtained using phase-transfer conditions.

Energy expenditure of Gambian women during peak agricultural activity measured by the doubly-labelled water method

The doubly-labelled water (2H218O) method was used to measure total energy expenditure (TEE) in ten non-pregnant, non-lactating (NPNL), six pregnant (P) and fourteen lactating (L) women in a rural Gambian community. Measurements were made on free-living subjects at a period of peak energetic stress when high agricultural work loads coincided with a hungary season to induce moderately severe negative energy balance. TEE averaged 10.42 (SD 2.08) MJ/d, equivalent to 1.95 (SD 0.38) times resting metabolic rate (RMR). The energy cost of physical activity plus thermogenesis, derived as TEE-RMR, averaged 4.94 (SD 1.96) MJ/d. Expressed per kg body-weight (103 kJ/kg per d) this component of expenditure was 2.5 times greater than comparative values from inactive, affluent women studied previously (39 kJ/kg per d). Estimated energy intake (EI) in a subset of the women (n 13) was only 4.80 (SD 1.58) MJ/d, yielding an apparent deficit of 6.08 MJ/d between EI and TEE. Weight changes suggested that endogenous fat oxidation accounted for only about 0.85 MJ/d, leaving an unexplained difference of over 5 MJ/d. Critical analysis of possible errors suggests that the new doubly-labelled water method has provided the most reliable estimates and that the estimates of EI were substantially in error. This finding has important consequences for other food intake studies.

Sorting of chromosomes by magnetic separation

Chromosomes were isolated from Chinese hamster x human hybrid cell lines containing four and nine human chromosomes. Human genomic DNA was biotinylated by nick translation and used to label the human chromosomes by in situ hybridization in suspension. Streptavidin was covalently coupled to the surface of magnetic beads and these were incubated with the hybridized chromosomes. The human chromosomes were bound to the magnetic beads through the strong biotin-streptavidin complex and then rapidly separated from nonlabeled Chinese hamster chromosomes by a simple permanent magnet. The hybridization was visualized by additional binding of avidin-FITC (fluorescein) to the unoccupied biotinylated human DNA bound to the human chromosomes. After magnetic separation, up to 98% of the individual chromosomes attached to magnetic beads were classified as human chromosomes by fluorescence microscopy.

Effect of histrionicotoxin on ion channels in synaptic and conducting membranes of electroplax of Electrophorus electricus

Histrionicotoxin (HTX) at low concentrations of 5-10 microM blocks the postsynaptic potential of the electroplax of Electrophorus electricus. At 100-fold higher concentrations, HTX blocks the directly evoked action potentials of the conducting membrane. The pH dependence of the blockade by HTX at synaptic channels is different from that at the conducting membrane. At the synapse HTX is more potent at acid pH, while at the conducting membrane it is more potent at basic pH. HTX at high concentrations antagonizes the effects of batrachotoxin, indicative of an effect on the batrachotoxin-sensitive sodium channels involved in action potential generation. While the effects of HTX on the synaptic channels are concentration, time, and pH dependent, the effects on the channels of the conducting membrane are, in addition, use dependent, suggesting interactions of HTX with the activated forms of these channels.

Phosphoenol-3-bromopyruvate. A mechanism-based inhibitor of phosphoenolpyruvate carboxylase from maize

Phosphoenol-3-bromopyruvate is an excellent competitive inhibitor (versus phosphoenolpyruvate) of maize phosphoenolpyruvate carboxylase (Ki = 30 microM), provided that preincubation of enzyme with inhibitor is avoided. If the enzyme is preincubated with inhibitor in the presence of Mn2+ and HCO3(-), complete inactivation occurs over the course of about 1 h. The inactivation is first order in enzyme and is saturable with respect to inhibitor, with an apparent Michaelis constant of 67.5 microM and a half-life at high inhibitor concentration of 13.4 min. The inactivation is inhibited by phospholactate and is much slower at low HCO3(-) concentration. Incubation of the enzyme with phosphoenol-3-bromopyruvate in the presence of H14CO3(-) and Mn2+ followed by treatment with NaBH4 leads to incorporation of 14C into the inactive enzyme. If treatment with NaBH4 is omitted, the enzyme is inactivated, but no 14C is incorporated into the inactive product. It appears that phosphoenol-3-bromopyruvate is a mechanism-based inactivator of phosphoenolpyruvate carboxylase, probably because of enzyme-catalyzed conversion to 3-bromooxalacetate, which alkylates the enzyme.

Displacement currents in lipid bilayer membranes

The processes of charge redistribution in phospholipid bilayer membranes have been examined by voltage clamping. Different types of phospholipids dissolved in n-decane were used as membranes and the membranes were made conducting by adding ionophores. The relaxation processes were found to be composed of at least two exponential decays of which the fast process can be explained in terms of a charge redistribution between the surface layers and the interior of the membrane, following the step in potential. The effect on this of varying the lipid composition, the external solution conditions and the applied potential are described in terms of changes in the capacitance CP and the resistance RP of the surface layers. A model in which a structural rearrangement of the lipid polar groups is responsible for the observed changes in CP and RP is also discussed.

Voltage-dependent conductance induced by hemocyanin in black lipid films

When hemocyanin is added to a black lipid film, the conductance increases in discrete steps. For negative potentials the single step conductance is constant, but for positive potentials the step conductance appears to decrease as the potential increases. At high positive potentials the conductance fluctuates between several levels. These data suggest that, in lipid membranes, hemocyanin conducts ions through discrete channels. The voltage-dependent conductance observed at high levels of conductance seems to be a consequence of the properties of the conductance of the single channel.

The photochemical rearrangement of 5-(1',5'-Dimethylhex-4'-enyl)-6-methoxy-7a-methyl-3H-indazole-4,7(3aH,7aH)-dione, the pyrazoline derivative of O-methylperezone

Irradiation of the pyrazoline derivative of O-methylperezone (2) by ultraviolet light yielded the tricyclic compounds (4) and (5), the tetra substituted compound (3) and the tetracyclic compound (6).