The influence of oxygenated sterol compounds on dipalmitoylphosphatidylcholine bilayer structure and packing

Fourier Transform Infra-red and Raman Spectroscopies indicate that 7 alpha-hydroxycholesterol and 7-ketocholesterol have a diminished capacity to condense (increase the packing order of) fluid-state dipalmitoylphosphatidylcholine (DPPC) acyl chains when compared with the effects of cholesterol and the other oxidized sterols studied. DPPC head groups were also more ordered by 7-ketocholesterol over the temperature range 10 degrees - 70 degrees C. Primary effects of these sterols appear to be associated with the hydrophillic regions of the DPPC bilayer, although packing arrangements with acyl chains are also involved. Phosphate and acyl chain ester groups were observed to possess a packing order which was invariant which indicates that these may be the target groups in the interaction with 7-ketocholesterol. A surprising observation was the synergistic amplification of the effects of 7-ketocholesterol by the presence of cholesterol in the DPPC bilayer.

Short-term measurement of carbon isotope fractionation in plants

Combustion-based studies of the carbon-13 content of plants give only an integrated, long-term value for the isotope fractionation associated with photosynthesis. A method is described here which permits determination of this isotope fractionation in 2 to 3 hours. To accomplish this, the plant is enclosed in a glass chamber, and the quantity and isotopic content of the CO(2) remaining in the atmosphere are monitored during photosynthesis. Isotope fractionation studies by this method give results consistent with what is expected from combustion studies of C(3), C(4), and Crassulacean acid metabolism plants. This method will make possible a variety of new studies of environmental and species effects in carbon isotope fractionation.

Improved complete response rate and survival in advanced head and neck cancer after three-course induction therapy with 120-hour 5-FU infusion and cisplatin

In a series of three consecutive pilot studies carried out between 1977 and 1981 at Wayne State University, Detroit, Michigan, designed to test the feasibility of multimodality therapy in patients with previously untreated advanced squamous cell carcinoma of the head and neck, patients received three different induction chemotherapy regimens: cisplatin + Oncovin (vincristine) + bleomycin (COB) for two courses; 96-hour 5-fluorouracil (5-FU) infusion and cisplatin for two courses, or 120-hour 5-FU infusion + cisplatin for three courses. Over-all response rates (complete response + partial response) to each of the three induction chemotherapy regimens were high: 80%, 88%, and 93%, respectively. Superior complete response rate in the group receiving three courses of 120-hour 5-FU infusion + cisplatin was 54% versus 29% for COB and 19% for two-course 96-hour 5-FU infusion + cisplatin (P = 0.04). Significant survival advantage at 18 months minimum follow-up for the group receiving three courses of 120-hour 5-FU + cisplatin induction therapy was found. Actual T and N stage may influence the clinical complete response rate. Responders to initial chemotherapy have significantly better survival as compared to nonresponders regardless of subsequent surgery and/or radiotherapy. These studies show that a multimodality approach to management of advanced head and neck cancer is feasible. Superior complete response rate and survival in one of the treatment groups suggest that choice of induction chemotherapy regimens and/or number of courses is of prime importance in such multimodality treatment programs.

Cosmetic caliper for use with flail leg

A new type of long leg brace made of polypropylene with an internal shoe foot piece seems to offer distinct advantages over the older, conventional type of calipers.