Effect of pregnancy and lactation on triglycerides of very-low-density lipoproteins of rat plasma.

Triglyceride in the blood of rats increased during pregnancy, decreased to control during lactation, and increased again on weaning. The triglyceride content of the very-low-density lipoproteins (d less than 1.006 g/ml) changed in parallel with that of the plasma, and its magnitude indicated that it was chiefly responsible for the transport of triglycerides in the blood. These changes were accompanied by changes in the electrophoretic pattern of the lipoproteins of rat plasma, but no such changes were observed in lipoproteins of ovine and caprine serum.     

Simultaneous comparison of three noninvasive oximeters in healthy volunteers

Noninvasive monitoring of arterial hemoglobin oxygen saturation (SaO2) from the Nellcor N-100 and the Ohmeda-Biox 3700 pulse oximeters were compared with SaO2 measured simultaneously by the Hewlett-Packard 47201A ear oximeter. A total of 868 pairs of data points ranging in saturation from 55-100% were obtained from 31 healthy adult volunteers of different ages, sex, skin pigmentation, height, weight, hematocrit, and smoking habits. Steady state and rapidly changing hypoxic conditions were achieved by varying the inspired O2 concentration between 10 and 100%. Measurements were analyzed by means of linear regression. The equations for the best fitted linear regression line between the Nellcor and the Ohmeda-Biox pulse oximeters as compared to the reference Hewlett-Packard ear oximeter readings were Y = 0.92X + 7.45 and Y = 1.10X - 10.73, respectively. Our study showed that despite a very close correlation among these three oximeters (r = 0.98), when compared to the Hewlett-Packard ear oximeter, the Nellcor pulse oximeter overestimates SaO2 by 2-4%, whereas the Ohmeda-Biox pulse oximeter underestimates SaO2 by 3-6% for SaO2 levels between 70 and 55%.     

Simple and efficient generation in vitro of nested deletions and inversions: Tn5 intramolecular transposition

We have exploited the intramolecular transposition preference of the Tn 5 in vitro transposition system to test its effectiveness as a tool for generation of nested families of deletions and inversions. A synthetic transposon was constructed containing an ori, an ampicillin resistance (Ampr) gene, a multi-cloning site (MCS) and two hyperactive end sequences. The donor DNA that adjoins the transposon contains a kanamycin resistance (Kanr) gene. Any Amprreplicating plasmid that has undergone a transposition event (Kans) will be targeted primarily to any insert in the MCS. Two different size targets were tested in the in vitro system. Synthetic transposon plasmids containing either target were incubated in the presence of purified transposase (Tnp) protein and transformed. Transposition frequencies (Ampr/Kans) for both targets were found to be 30-50%, of which >95% occur within the target sequence, in an apparently random manner. By a conservative estimate 10(5) or more deletions/inversions within a given segment of DNA can be expected from a single one-step 20 microl transposition reaction. These nested deletions can be used for structure-function analysis of proteins and for sequence analysis. The inversions provide nested sequencing templates of the opposite strand from the deletions.     

Advances in diode laser pumps

Diode laser pumps for solid-state lasers are reviewed with special emphasis on current and future capabilities. Included are discussions of pumps for CW (continuous-wave) and quasi-CW operation, and end- and side-pumping configurations