PubMed Health⌕ Search

Biomedical subjects

C M Stevens

Publications and source records attributed to C M Stevens.

32 records · Page 2Linked to original sources
PubMed1979

Biosynthesis of a 7-alpha-methoxycephalosporin. Incorporation of molecular oxygen.

A 7-alpha-methoxycephalosporin containing a carbamoyloxymethyl substituent at C-3 (cephamycin C) has been isolated from the extracellular fluid of an aqueous suspension of Streptomyces clavuligerus shaken in the presence of 18O2. The cephalosporin has been converted into its N-acetyl dimethyl ester and the distribution of 18O in the latter determined by chemical-ionization mass spectrometry. The results indicate that the oxygen atom of the methoxy group, as well as that linked to the exocyclic methylene group at C-3, is derived from molecular O2.

Cephalosporins↗
PubMed1975

Telemetered renal responses in dogs during detection of explosives.

The primary objectove of this work was to develop and test a method of measuring and characterizing renal hemodynamic responses in unrestrained dogs. Recordings of left kidney blood flow and abdominal aortic pressure were obtained from unrestrained dogs through the use of a two-channel implanted telemetry system during episodes of search and detection of simulated explosives. In each of a number of sequences, the dog was first given a start signal, and after locating the hidden device, was rewarded with food. Data were assessed at the start, find, and recovery segments. The dynamic flow and pressure, together with a hydraulic renal model, were used to derive the total preglomerular and postglomerular vascular resistances and the mean level of glomerular hydrostatic pressure. Data from three dogs obtained by telemetry and analyzed through the use of the model have shown that compared to the start of the test, the location of hidden explosives results in a decrease in both the level of mean aortic blood pressure and the preglomerular resistance; whereas, the reward results in an elevation of mean blood pressure and preglomerular resistance. The postglomerular resistance varied less than the preglomerular resistance, and mean flow did not vary significantly. This work has shown that the stimulation of a reward and the successful performance of a task lead to significant renal responses in dogs. It has further shown that telemetry, when employed with improved data analysis techniques, permits renal hemodynamics to be assessed in unrestrained animal subjects.

Animals↗
PubMedDate not supplied

Introductory small cash incentives to promote child spacing in India.

The Ammanpettai Family Welfare Program began in 1985 as a pilot program to determine whether offering small monthly cash incentives for a limited period would be a cost-effective way to increase the use of modern temporary methods of contraception among rural Indian women who do not want to become pregnant but are not ready to adopt sterilization. The program has demonstrated that a modest cash incentive for 3-5 months attracts very large numbers of women to a clinic where they learn about and are provided with the pill, condoms, or the IUD. In catchment areas where official government reports showed temporary-methods prevalence rates of 3-5 percent at best, the Ammanpettai incentive program has attracted up to 70 percent of eligible women to join the program and try the method of their choice. By requiring that participants bring their youngest child to the clinic, the program provides for mother and child health surveillance, including immunizations. The great majority of rural women who join the program work as field laborers, have little or no schooling, and have little knowledge of or experience with modern contraceptive methods. Continuation rates are 25-50 percent at one year if follow-up is maintained by village resident women distributors. The program has been extended to several rural primary health centers in Thanjavur District, to 14 government health posts in the city of Madras, and to a semiurban area and several rural areas in Bihar. The cost-effectiveness of this program compares favorably with that of the current government family welfare program.

Adult↗