Search PubMed⌕ Search

Biomedical subjects

S K Smith

Publications and source records attributed to S K Smith.

At least 199 records · Page 11Linked to original sources
PubMed1987

Glucocorticoids do not share with progesterone the potent inhibitory action on prostaglandin synthesis in human proliferative phase endometrium.

The action of progesterone and glucocorticoids on human proliferative phase endometrium has been investigated using isolated fragments of endometrium cultured for 2 to 3 days. The action of progesterone (200-500 nM) in this system is to reduce prostaglandin F (PGF) production by 93 to 96%. This inhibition is considerably greater than the inhibitions observed using collagenase dispersed stromal or glandular cells. The addition of arachidonic acid (5 micrograms/ml) increased the production of the control wells but did not overcome the inhibitory effect of progesterone. When endometrial fragments were cultured for 48 hr in the presence of progesterone and subsequently homogenized and incubated, there was no difference in PG production between the progesterone treated tissue and the controls. In a separate series of experiments the effect of progesterone (500nM) was compared with cortisol (500nM) and the synthetic glucocorticoid dexamethasone (100nM) this dose of progesterone gave a 96% reduction in PGF synthesis but neither cortisol nor dexamethasone inhibited PGF production.

Arachidonic Acid↗
PubMed1987

Progesterone and antiprogestins, a comparison of their effect on prostaglandin production by human secretory phase endometrium and decidua.

The mechanism by which progesterone inhibits PG production is not clear. In systems using isolated human endometrial fragments, progesterone has been shown to inhibit PG production markedly. We have used such a system to test the action of two antiprogesterone steroids RU486 (Roussell-Uclaf) and ZK98734 (Schering) on isolated human endometrial and decidual tissue, with and without added progesterone. Progesterone (200 nM) reduced PGF2 alpha production by the secretory phase endometrium from 10.9 ng/mg tissue/24 hr to 1.9 ng/mg/24hr on the third day of culture (p less than .01) and this effect was antagonised by the addition of either 200 nM RU486 or 200 nM ZK98734 (6.3 and 7.2 ng/mg/24 hr respectively). The antiprogestins on their own showed a slight inhibitory effect on day 3 and RU486 treatment resulted in a significant (p less than .05) decrease in PG production from control. PGE and the main 13,14-dihydro-15-keto metabolites of E and F were also significantly decreased by progesterone and restored by the antiprogestins. The PG production by decidua increased on days 2 and 3 in response to progesterone + antiprogestins but this was not significant. This data shows that the inhibition of PG production shown by progesterone, acting on secretory phase endometrium cultured as tissue fragments, is reversible by the receptor blocking antiprogestins.

Adult↗
PubMed1987

Tests of forecast accuracy and bias for county population projections.

"This article deals with the forecast accuracy and bias of population projections for 2,971 counties in the United States. It uses three different projection techniques and data from 1950, 1960, 1970, and 1980 to make two sets of 10-year projections and one set of 20-year projections. These projections are compared with census counts to determine forecast errors. The size, direction, and distribution of forecast errors are analyzed by size of place, rate of growth, and length of projection horizon. A number of consistent patterns are noted, and an extension of the empirical results to the production of confidence intervals for population projections is considered." A comment by Paul M. Beaumont and Andrew M. Isserman is included (pp. 1,004-9) together with a rejoinder by the author (pp. 1,009-12). This is a revised version of a paper presented at the 1986 Annual Meeting of the Population Association of America (see Population Index, Vol. 52, No. 3, Fall 1986, p. 456).

Americas↗
PubMed1987

The effect of the antiprogestins RU 486 and ZK 98734 on the synthesis and metabolism of prostaglandins F2 alpha and E2 in separated cells from early human decidua.

Enriched preparations of glandular and stromal cells were obtained from early human decidua and incubated for 24 h in the presence of two progesterone antagonists, RU 486 (17 beta-hydroxy-11 beta-[4-dimethylaminophenyl]17 alpha-[1-propynyl]-estra-4,9-dien-3-one) and ZK 98734 (17 beta-hydroxy-11 beta-4[4-dimethylaminophenyl]17 alpha-[3-hydroxy-1-propynyl]estra-4,9-dien-3-one) to determine the effect of the antiprogestins on the release of prostaglandin F2 alpha (PGF2 alpha) and PGE2 and their subsequent conversion to 15-keto-13,14-dihydro-PGF2 alpha and 15-keto-13,14-dihydro-PGE2. In the presence of exogenous arachidonic acid (AA, 30 microM), both steroids stimulated PGF2 alpha release by glandular, but not stromal, cells (P less than 0.001) and inhibited the metabolism of PGF2 alpha by the glandular fraction (P less than 0.005 and P less than 0.001 respectively). In the absence of exogenous AA, RU 486 and ZK 98734 stimulated the release of PGF2 alpha from glandular, but not stromal, cells (P less than 0.001 and P less than 0.005, respectively). Neither steroid altered the release or metabolism of PGE2 when the cells were incubated with AA, but both RU 486 and ZK 98734 increased the release of PGE2 by glandular, but not stromal, cells when incubated without AA (P less than 0.005 and P less than 0.001, respectively). Both steroids inhibited the metabolism of PGE2 under these conditions (P less than 0.05). These results suggest that 1) antiprogestins stimulate the synthesis of PGs by glandular cells in early human decidua, but do not alter the synthesis of PGs by stromal cells; 2) this stimulation of PG synthesis involves an effect on cyclooxygenase activity and is not a consequence of increased availability of endogenous AA; 3) the metabolism of PGs by glandular cells is altered by RU 486 and ZK 98734; 4) as RU 486 has greater antiglucocorticoid activity than ZK 98734, these results suggest that both steroids act on decidua by antagonizing endogenous progesterone rather than glucocorticoid activity.

Cells, Cultured↗
PubMed1987

LRH agonist buserelin as a post-partum contraceptive: lack of biological activity of buserelin in breast milk.

To evaluate the possibility of using the LRH agonist buserelin as a contraceptive for lactating women we have investigated the passage of buserelin into breast milk and explored possible biological activity in the infant. Eleven mothers received 600 micrograms buserelin by nasal spray. Buserelin was measured by radioimmunoassay in the breast milk of these mothers, and values ranged from undetectable levels (less than 15 pg/ml) to 8800 pg/ml. The maximum amount of buserelin that an infant could ingest during an average feed would be 1-2 micrograms. In adult men ingestion of 600 micrograms buserelin dissolved in cows milk was without biological effect upon both serum and urinary levels of luteinizing hormone. There was no change in the levels of LH found in the urine of infants fed by women who had received 600 micrograms buserelin by nasal spray. We conclude that the small amount of buserelin passing into the breast milk of these volunteers was without biological activity when ingested by the infant.

Administration, Intranasal↗
PubMed1986

The effect of deliberate omission of Trinordiol or Microgynon on the hypothalamo-pituitary-ovarian axis.

The effect of deliberate omission of a phased formulation pill, Trinordiol (ethinyl estradiol 30 micrograms + levonorgestrel 50 micrograms: 6 tablets; ethinyl estradiol 40 micrograms + levonorgestrel 75 micrograms: 5 tablets; ethinyl estradiol 30 micrograms + levonorgestrel 125 micrograms: 10 tablets) or a low-dose, combined, oral contraceptive pill, Microgynon (ethinyl estradiol 30 micrograms + levonorgestrel 150 micrograms: 21 tablets) on the hypothalamo-pituitary-ovarian axis were studied. Thirty-six women were recruited to the study and divided equally between the two types of pill. Medication was begun on the 8th pill-free day of the cycle and continued for 7 days (Group 1), 14 days (Group 2) or 21 days (Group 3). Levels of FSH, LH, estradiol (E2) and progesterone (P) were measured in plasma on alternate days during the final week of pill therapy, and daily for the 7 days after stopping the pill. For the first 2 weeks of pill therapy, follicular activity, as judged by plasma levels of E2, was greater in women taking Trinordiol than in those taking Microgynon, but was similar in both groups by the third week of pill treatment. Five women taking Trinordiol (2 in Group 1 and 3 in Group 2) had plasma levels of E2 in excess of 500 pmol/l whilst taking the pills, and only 1 patient achieved this degree of follicular activity after stopping the tablets. One woman who had taken 7 days of Trinordiol (Group 1) showed a rise of plasma levels of P to 6.8 nmol/l, but luteinization did not occur in any of the remaining 35 women who took Trinordiol or Microgynon. These findings suggest that follicular activity is less completely suppressed by Trinordiol than Microgynon, at least in the first 2 weeks of pill therapy, but that normal ovulation is still a rare event in the week after cessation of either of these pills, even if only 7 days of medication have been taken.

Contraceptive Agents, Female↗
PubMed1986

A review and evaluation of the housing unit method of population estimation.

"The housing unit (HU) method is used by public and private agencies throughout the United States to make local population estimates. This article describes many of the different types of data and techniques that can be used in applying the HU method, and it discusses the strengths and weaknesses of each. Empirical evidence from four different states is provided, comparing the accuracy of HU population estimates with the accuracy of other commonly used estimation techniques. Several conclusions are drawn regarding the usefulness of the HU method for local population estimation."

Americas↗
PubMed1986

Using Medicare data for short-run projections of the elderly population.

As the elderly population of the United States grows in absolute number and as a proportion of total population, accurate projections of that population become increasingly important for sound policy decisions. Cohort component techniques are typically used for state and local projections of the elderly population, but are often outdated or even nonexistent for many local areas. This paper suggests an alternative approach, based on Medicare data and simple projection techniques. Projections for several base periods and projection horizons are made for all states and for counties in Florida and are compared with actual Medicare enrollment. On the basis of these comparisons it appears that Medicare data and simple projection techniques can produce very useful short-run projections of the elderly population for states and local areas.

Aged↗
PubMed1986

Accounting for migration in cohort-component projections of state and local populations.

Migration is the most difficult component of state and local population growth to forecast accurately because it is more volatile than either births or deaths, and subject to much larger fluctuations within a short period of time. In addition, migration rates can be based on several different measures of migration and the base population. The choice of the appropriate base population has received little attention from demographic researchers, but can have a tremendous impact on population projections. In this article, I develop three different models for projecting migration, each using a different denominator for migration rates. Population projections for ten states are made, using identical data and cohort component techniques, except for the different formulations of migration rates. Differences among the three sets of projections are noted, and conclusions are drawn regarding their usefulness as forecasts of population growth.

Emigration and Immigration↗
PubMed1985

Plasma gonadotrophin and ovarian steroid concentrations in women with menstrual cycles with a short luteal phase.

Daily plasma concentrations of FSH, LH, oestradiol-17 beta and progesterone were compared for 12 cycles with a short luteal phase and 19 cycles with a luteal phase of normal length (i.e. cycles in which the luteal phase lasted 12 or more days). FSH and LH concentrations were suppressed in short luteal-phase cycles in the early follicular phase and the length of the follicular phase was prolonged (median duration, 14.5 days, range 13-21 days: compared with 12 days, range 9-17, in control cycles; P less than 0.025). Preovulatory oestradiol-17 beta values and the mid-cycle concentrations of FSH and LH were similar in both groups. Plasma progesterone values in the luteal phase were similar in both groups over the 2nd to 5th days inclusive after the midcycle LH peak but declined in the short luteal phases thereafter. In short luteal-phase cycles, menstruation occurred in the presence of higher levels of oestradiol-17 beta and progesterone than in cycles of normal length and the rise of gonadotrophin in the late luteal phase of the cycle was delayed. These findings suggest that in cycles with a short luteal phase there is a lack of synchrony between the ovarian and menstrual events.

Estradiol↗
PubMed1985

Abnormalities in the expression of the leucocyte-common antigen in chronic lymphocytic leukaemia.

The surface glycoproteins of lymphocytes isolated from patients suffering from B cell chronic lymphocytic leukaemia (B-CLL) have been studied by radioactive labelling with impermeable probes and with MoAb. Several features not found in normal B cells have been observed. The abnormalities found in the expression of polypeptides of the leucocyte common (L-C) antigen, identified by appropriate MoAb, have been examined in detail. It has been shown by both biochemical analysis and MoAb binding that this group of polypeptides can, within a panel of B-CLL patients, range from a typical B cell pattern to the pattern resembling that normally found in T cells. The T lymphocyte profile is correlated with a poor prognosis (MVA C rating) and in the one patient where a change in the glycoprotein profile towards that of the T cell was observed, the change coincided with a clinical deterioration. The biological significance of the molecular diversity is discussed.

Antigen-Antibody Reactions↗
PubMed1985

Surface glycoproteins as markers of the cellular status of B chronic lymphocytic leukaemia lymphocytes.

The phenotype of B CLL cells is investigated with respect to their surface glycoproteins. These glycoproteins are identified by vectorial tritiation followed by 1 and 2 dimensional gel electrophoresis, and by lectin and MoAb binding using immunoprecipitation and flow cytometry. The profiles of the CLL cells are compared with those of normal B cells, prepared from tonsils, and T cells from peripheral blood. The CLL cells show many similarities with T cells, particularly the expression of glycoproteins which bind the MoAbs gpL 115, F10-44-2 and EZB 52, and a complex set of binding sites for Helix pomatia lectin. The significance of these observations in terms of the cellular origins of the leukaemic lymphocytes is discussed.

Antibodies, Monoclonal↗
PubMed1985

Dysfunctional uterine bleeding.

Dysfunctional uterine bleeding initially described abnormal bleeding unassociated with pregnancy, infection or tumour, and was assumed mainly to follow abnormal ovarian function. In conjunction with other menstrual disorders it is now recognized to be a problem predominantly of ovulatory cycles (Table 1). This article discusses the reasons behind this change of emphasis and medical approaches to the problem.

Anovulation↗
PubMed1984

Effects of 17 beta-estradiol and progesterone on the levels of prostaglandins F2 alpha and E in human endometrium.

17 beta-estradiol and progesterone were administered to post-menopausal women to determine their effects in vivo on the capacity of human endometrium to synthesize prostaglandins (PGs) F2 alpha and E. Basal amounts of PGF2 alpha and PGE synthesized by endometrium exposed to 17 beta-estradiol and progesterone were significantly higher than the levels produced by endometrium exposed to 17 beta-estradiol alone (p less than 0.02 for both PGs). Levels found in the former endometrium were broadly comparable to levels in secretory endometrium and in the latter to amounts found in proliferative endometrium of spontaneous, ovulatory cycles.

Dinoprost↗
PubMed1984

A comparison of population estimation methods: housing unit versus component II, ratio correlation, and administrative records.

The authors present the case for the housing unit (HU) method as a technique for estimating the population of states and local areas in the United States. They "evaluate population estimates produced by the housing unit method and by three other commonly used methods: component II, ratio correlation, and administrative records. Basing [the] analysis on 1980 census data from 67 counties in Florida and testing for precision, bias, and the distribution of errors, [they find that] application of the HU method performs at least as well as the more highly acclaimed methods of local population estimation."

Americas↗
PubMed1984

Effect of bromocriptine on menstrual cycle length.

Forty-seven women with regular ovulatory menstrual cycles and normal plasma prolactin levels were treated with different doses of bromocriptine, and changes in follicular and luteal phase length determined by daily estimation of plasma gonadotrophin concentration. Follicular phase length was highly significantly reduced from a median duration of 12.7 days in the basal cycle to 11.7 days in the first treatment cycle, and to 10.7 days during the second treatment cycles. The length of the luteal phase was unaltered by treatment with bromocriptine. Reduction of follicular phase length was not influenced by the dose of bromocriptine used, and it is concluded that this effect is a consequence of the reduction of plasma prolactin concentration.

Adult↗