Continuous non-invasive blood pressure monitoring by brachial artery displacement method in high-risk surgical patients

Continuous non-invasive blood pressure (CNBP) measurements were compared to invasive radial artery pressure recordings in 26 patients with cardiac, vascular and/or pulmonary disease. Patients were studied during general anaesthesia (n = 6), regional anaesthesia (n = 10), or combined technique (n = 10) for abdominal or transurethral surgery. CNBP was obtained from a cuff placed around the upper arm and simultaneously compared to invasive pressure from the ipsilateral radial artery. A CNBP device (7001 Cortronic) used intermittent oscillometric measurement for calibration. Through a cuff continuously inflated to a pressure of 20 mmHg, a microprocessor-controlled electro-pneumatic acquisition system sensed displacements of the brachial artery wall. Amplified, digitally converted, filtered and transformed data were displayed as a continuous pulse pressure waveform and digital pressure values on the screen. The CNBP method functioned without disturbances before surgery in all patients. Intra-operative use of electrocautery or a spontaneous occurrence of warning on the screen repeatedly triggered oscillometric recalibration, hence CNBP measurements were discontinued in nine patients. Coefficients of correlation (r) of all invasive and CNBP pairs (n = 1111) were 0.68, 0.58 and 0.70 for systolic, diastolic, and mean blood pressures, respectively. Prediction errors (bias, mean +/- SD) were -13.6 +/- 22.5 mmHg (on average CNBP < invasive pressure) for systolic, +13.0 +/- 12.4 mmHg (CNBP > invasive pressure) for diastolic and +5.0 +/- 13.9 mmHg (CNBP > invasive pressure) for mean CNBP, as compared to radial artery pressure values. Absolute errors (precision) were 25.3 +/- 9.4 mmHg for systolic, 17.4 +/- 4.5 mmHg for diastolic, and 13.9 +/- 4.6 mmHg for mean CNBP. During anaesthesia induction (n = 672) the difference between consecutive measurements (trend of pressure changes) with invasive and CNBP method exceeded 20 mmHg in 90 (13.3%) instances for systolic, in 33 (4.9%) instances for diastolic, and in 45 (6.6%) instances for mean blood pressure. In conclusion, the CNBP method by brachial artery wall displacement failed to measure the blood pressure reliably and to display the trend of pressure changes correctly during anaesthesia induction. In its present form this CNBP method should not replace invasive blood pressure monitoring in high-risk patients neither for anaesthesia induction nor during non-thoracic surgical procedures.     

Neutralization of human immunodeficiency virus type 1 by antibody to gp120 is determined primarily by occupancy of sites on the virion irrespective of epitope specificity

We investigated the relative importance of binding site occupancy and epitope specificity in antibody neutralization of human immunodeficiency virus (HIV) type 1 (HIV-1). The neutralization of a T-cell-line-adapted HIV-1 isolate (MN) was analyzed with a number of monovalent recombinant Fab fragments (Fabs) and monoclonal antibodies with a range of specificities covering all confirmed gp120-specific neutralization epitopes. Binding of Fabs to recombinant monomeric gp120 was determined by surface plasmon resonance, and binding of Fabs and whole antibodies to functional oligomeric gp120 was determined by indirect immunofluorescence and flow cytometry on HIV-infected cells. An excellent correlation between neutralization and oligomeric gp120 binding was observed, and a lack of correlation with monomeric gp120 binding was confirmed. A similar degree of correlation was observed between oligomeric gp120 binding and neutralization with a T-cell-line-adapted HIV-1 molecular clone (Hx10). The ratios of oligomer binding/neutralization titer fell, in general, within a relatively narrow range for antibodies to different neutralization epitopes. These results suggest that the occupancy of binding sites on HIV-1 virions is the major factor in determining neutralization, irrespective of epitope specificity. Models to account for these observations are proposed.     

Depression of lipogenesis in swine adipose tissue by specific dietary fatty acids

The objective of this study was to document the influence of specific dietary fatty acids on rates of lipid synthesis and sensitivity to insulin in porcine adipose tissue. Weanling pigs were assigned to one of six groups, and each group was fed diets containing 10 g/100 g of added cornstarch or 10 g/100 g of added fatty acid. The fatty acid-enriched diets contained either a combination of 14:1 plus 16:1 (14:1/16:1 diet), 16:0, 18:0, 18:1, or 18:2 (n-6). With the exception of the cornstarch diet, all diets contained approximately 35% 14:0. Subcutaneous adipose tissue samples were collected at slaughter from the area overlying the first cranial vertebra. Fresh samples were incubated for 2 h in 20 mM glucose and 0, 10, 100 or 1,000 microU/mL of porcine insulin. The smallest adipocytes were observed in adipose tissue from pigs fed the 16:0 or 18:2 diets. Glucose incorporation into lipids was greater (P < .05) in adipose tissue from cornstarch-fed pigs than in adipose tissue from the other treatment groups. Lipogenesis was 67, 53, 35, 32, and 20% lower (P < .05) in adipose tissue from 16:0-, 14:1/16:1-, 18:0-, 18:2-, and 18:1-fed pigs, respectively, than in adipose tissue from the cornstarch-fed pigs. Insulin increased lipogenesis by 19% (P < .05) in adipose tissue from the cornstarch-fed pigs and by 15 to 40% (P < .05) in adipose tissue from the 14:1/16:1-fed pigs. Insulin did not stimulate lipogenesis (P > .4) in adipose tissue from pigs fed the 16:0, 18:0, or 18:1 diets. The data suggest that fatty acid chain length and unsaturation are determinants in the effects of dietary fat and insulin on de novo lipogenesis.     

Bifidobacterium longum and lactulose suppress azoxymethane-induced colonic aberrant crypt foci in rats

Bifidobacterium longum has been shown to afford protection against colon tumorigenesis. Lactulose, a keto analog of lactose, serves as a substrate for preferential growth of Bifidobacterium. It is not known whether feeding lactulose along with B. longum will have any advantage over feeding of B. longum alone. To test this combination effect, 61 male Fisher 344 weanling rats were divided into four groups of 15 rats each (16 in the control group) and assigned to one of the following four diets for 13 weeks: (i) AIN76A (control, C); (ii) C + 0.5% B. longum (C+Bl, containing 1 x 10(8) viable cells/g feed); (iii) C + 2.5% lactulose (C+L); (iv) C + 0.5% B. longum + 2.5% lactulose (C+Bl+L). All animals received a s.c. injection of azoxymethane at 16 mg/kg body wt at 7 and 8 weeks of age. Colons of 10 rats from each dietary group were analyzed for aberrant crypt foci (ACF), which are preneoplastic markers. Colonic mucosa and livers from five rats were analyzed for glutathione S-transferase (GST, a Phase II enzyme marker). Results indicate that feeding of lactulose and B. longum singly and in combination reduces the number of ACF (P = 0.0001) and the total number of aberrant crypts significantly (P = 0.0005). The total number of ACF in diets C, C+Bl, C+L and C+Bl+L were 187 +/- 9, 143 +/- 9, 145 +/- 11 and 97 +/- 11 respectively. There was no significant difference in weight gain among treatments. Colonic mucosal GST levels were significantly (P = 0.05) higher in the Bl and L groups compared with group C. Initially there was a mild diarrhea in lactulose-fed rats. There was a positive correlation between higher cecal pH and number of ACF. Results of the study indicate that Bifidobacterium and lactulose exert an additive antitumorigenic effect in rat colon.     

Molecular phylogeny of glutathione-S-transferases

The glutathione-S-transferase (GST) protein superfamily is currently composed of nearly 100 sequences. This study documents a greater phylogenetic diversity of GSTs than previously realized. Parsimony and distance phylogenetic methods of GST amino acid sequences yielded virtually the same results. There appear to be at least 25 groups (families) of GST-like proteins, as different from one another as are the currently recognized classes. This diversity will require the design of a new nomenclature for this large protein superfamily. There is one well-supported large clade containing the mammalian mu, pi, and alpha classes as well as GSTs from molluscs, helminths, nematodes, and arthropods.     

Expression of a dominant-negative type II transforming growth factor beta (TGF-beta) receptor in the epidermis of transgenic mice blocks TGF-beta-mediated growth inhibition

To determine whether a functional type II receptor of transforming growth factor beta (TGF-beta) is required to mediate the growth inhibitory effect of TGF-beta on the skin in vivo, we have generated transgenic mice that overexpress a dominant negative-type II TGF-beta receptor (delta beta RII) in the epidermis. The delta beta RII mice exhibited a thickened and wrinkled skin, and histologically the epidermis was markedly hyperplastic and hyperkeratotic. In vivo labeling with BrdUrd showed a 2.5-fold increase in the labeling index over controls, with labeled nuclei occurring in both basal and suprabasal cells of transgenic epidermis. In heterozygotes, this skin phenotype gradually diminished, and by 10-14 days after birth the transgenic mice were indistinguishable from their normal siblings. However, when F1 mice were mated to homozygosity, perinatal lethality occurred due to the severe hyperkeratotic phenotype, which restricted movement. Cultured primary keratinocytes from delta beta RII mice also exhibited an increased rate of growth in comparison with nontransgenic controls, and were resistant to TGF-beta-induced growth inhibition. These data document the role of the type II TGF-beta receptor in mediating TGF-beta-induced growth inhibition of the epidermis in vivo and in maintenance of epidermal homeostasis.     

Historical redistribution under the Social Security Disability Insurance Program

This study uses Social Security administrative data on historical taxes and benefits by year, age, gender, and race for an ex post analysis of redistribution under the Disability Insurance (DI) program. The relationship between the taxes paid and benefits received to date under the program is described for successive cohorts as a whole and for specific race and gender groups both within cohorts and across time.     

Capillary tube resistive thermal cycling

A system that performs rapid thermal cycling of microliter and smaller liquid volumes inside glass capillary tubes that have an optically transparent thin film of indium-tin oxide (ITO) covering the exterior is described. The ITO film acts as both a heater and a temperature sensor, while cooling is accelerated with forced air. Unlike existing batch-mode thermal cycling systems, this system allows control over each sample's temperature profile. Temperature transition rates of 44 degrees Celsius per second during heating and 15 degrees Celsius per second during cooling have been achieved, allowing successful polymerase chain reaction (PCR) experiments to be performed in 20 min. Capillary external temperature can be regulated typically to within +/- 0.25 degrees Celsius, and peak temperatures more than 800 degrees Celsius have been demonstrated. Capillary internal (sample) temperatures at present are controllable typically to within 2 degrees Celsius. The resistive film can be used as a temperature sensor, and the optical transparency of the thin-film coating could permit fluorescent monitoring of the sample during thermal cycling, making this method well suited for real-time quantitative PCRs.