Suppression of sebum secretion with 13-cis-retinoic acid: effect on individual skin surface lipids and implications for their anatomic origin.

The contribution of the keratinizing epidermis to the human skin surface lipid film has been difficult to ascertain because, after its release from the epidermal cells, epidermally derived lipid inevitably becomes mixed with sebum. In the present study, the sustainable rates of production of the 5 neutral lipid classes found on the skin surface (triglycerides + free fatty acids, wax esters, cholesterol, cholesterol esters, and squalene) were measured on the foreheads of acne patients before, during, and following treatment with 13-cis-retinoic acid, a drug which suppresses sebum production profoundly. Since sebum production was high in the patients before treatment and was suppressed to a few percent of the pretreatment level in some of the patients during treatment, data covering a wide range of sebum production rates were obtained. By using squalene as a measure of sebum production and plotting the rates of production of the other lipid classes vs the rate of production of squalene, it was possible through extrapolation to estimate the residual (i.e., epidermal) rate of production of each lipid class at zero sebum production. The results indicated that epidermis releases triglycerides + free fatty acids and cholesterol to the skin surface. The cholesterol esters in freshly secreted skin surface lipids appeared to be almost entirely sebaceous in origin. Measurements were also made of the percentages of cholesterol esters in lipid collected from the scalp after several days' accumulation and were compared to corresponding values for the forehead lipid. The percentages of cholesterol esters in scalp lipid tended to rise when sebum production was suppressed by the drug, rather than remaining relatively constant as occurred in the freshly secreted forehead lipid. This result indicated that epidermis may contribute to skin surface cholesterol esters, probably through skin surface esterification of epidermal cholesterol.

Precise timing for peak relaxin and decreased progesterone secretion after hysterectomy in the pig.

Relaxin and progesterone secretion by aging corpora lutea (days 90-120) was examined in pregnant and lactating gilts compared with that in hysterectomized animals. The length of pregnancy is about 115 days in pigs. Unmated gilts were hysterectomized on day 6 (estrus = day 0). From days 90-101, relaxin concentrations in peripheral plasma remained consistently low in pregnant gilts (range, 0.7-1.5 ng/ml) and less (P less than 0.05) than those in hysterectomized animals (range, 0.9-3.5 ng/ml). Relaxin increased abruptly (P less than 0.01) to a peak of 66 ng/ml in pregnant gilts and 37 ng/ml in hysterectomized animals. Relaxin peaked in pregnant animals at 113 +/- 0.7 days (+/- SE) and in hysterectomized gilts at 113 +/- 0.7 days; gestation length averaged 114 +/- 0.8 days. In pregnant gilts, relaxin decreased from a peak of 66 to 11 ng/ml within 1 day and remained low (less than 1.0 ng/ml) in these lactating dams until day 120. In hysterectomized gilts, peak relaxin also decreased abruptly from 37 to 4.2 ng/ml, but remained consistently greater (P less than 0.05) than that in lactating dams. Although there were abrupt shifts in relaxin concentrations within 20 min, there was no evidence for consistent episodic relaxin release between days 112-116. Plasma progesterone concentrations were consistently greater (P less than 0.05) in hysterectomized than in pregnant gilts from days 102-110. Progesterone decreased abruptly in prepartum gilts (days 111-114) from 16 to 1.2 ng/ml and remained low during lactation (0.5 ng/ml). In hysterectomized animals, it decreased abruptly on days 110-113, ranging from 20-12 ng/ml, and remained at this lower level until day 120. These results clearly indicate that a precisely timed peak release of relaxin and coincident decrease in progesterone secretion occur in unmated hysterectomized gilts at the same time as those found a few hours preceding parturition during normal pregnancy. These abrupt shifts in relaxin and progesterone secretion on days 112-113 in both hysterectomized and pregnant gilts may be regulated autonomously from within the ovary or from the central nervous system and pituitary gland.

Effect of a nonsteroidal aromatase inhibitor on in vitro and in vivo secretion of estradiol and on the estrous cycle in ewes.

Three experiments were performed to study effects of decreased concentrations of estradiol-17 beta (E2) on lifespan and function of ensuing ovine corpora lutea (CL). In experiment 1, 52 follicles were collected from 10 ewes and placed into individual culture with 0 or .01 microCi 3H-androstenedione (10 ng; 3H-A) and 0, 10(-11), 10(-9), 10(-7), or 10(-5) M of a nonsteroidal aromatase inhibitor, CGS16949A (CGS). Concentrations of E2 secreted into the medium, and synthesis of estrogens as estimated by formation of 3H-water from 3H-A were decreased by 10(-5) and 10(-7) (P < .01), but not 10(-9) or 10(-11) M CGS. In experiment 2, luteolysis was induced in 24 ewes by injection of PGF2 alpha on days 5 to 10 of the estrous cycle (0 hr). Ewes received 0, 0.5, 1.0, 2.0 or 4.0 mg CGS per kg BW i.v. at -12, 0, 12 and 24 hr, and an ovulatory dose of hCG at 36 hr. Jugular (P < .001) and vena caval (P < .001) concentrations of E2 were decreased by CGS at all doses tested for 8 to 10 hr, but had returned to levels similar to control ewes by the time of the next injection. Concentrations of E2 around the time of the LH surge were similar in control and treated ewes. During the subsequent luteal phase, concentrations of progesterone (P4) were similar in control and treated ewes. Thus, transient decreases in E2 during the follicular phase were not deleterious to the subsequent luteal phase. In experiment 3, luteolysis was induced in 18 ewes by injection of PGF2 alpha on days 6 or 7 (0 hr) of the estrous cycle. Ewes received 0 or 1 mg CGS per kg BW i.v. every 8 hr from 0 to 40 hr. Ovulation was induced with hCG at 36 hr. CGS reduced jugular (P < .001) and vena caval (P < .001) concentrations of E2, prevented an endogenous surge of LH (P < .05) and increased (P < .001) concentrations of FSH. All ewes had ovulated a marked follicle by 72 hr, but onset of the luteal phase, as assessed by concentrations of P4, was delayed (P < .01) in ewes receiving CGS. Delayed luteal phases were not solely attributable to the presence of new CL or to luteinization of follicular cysts. When data were aligned according to the day ewes were observed in estrus, profiles of P4 did not differ with treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Concentrations of tissue-type plasminogen activator and relaxin in normal and induced-cystic follicles of gilts.

Manipulation of one ovary in prepubertal gilts treated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) results in cysts on the manipulated ovary and corpora lutea (CL) on the non-manipulated (control) ovary. Because tissue-type plasminogen activator (tPA) might play a role in follicular rupture and because relaxin might increase tPA production, concentrations of tPA and relaxin in manipulated and control follicles were measured at different stages of development. Prepubertal gilts were treated with 1000 IU PMSG followed by 750 IU hCG at 72 hr later. Follicles on one ovary in each gilt were manipulated at laparotomy 48 hr after PMSG administration. Gilts were ovariectomized at 72, 90, 108, 114, 144, and 216 hr after PMSG. Concentrations of tPA and relaxin were determined for follicular fluid from follicles dissected free of ovarian stroma and snap frozen in liquid nitrogen and media from follicles cultured for 48 hr. Relaxin did not differ between treatment groups (manipulated and control) at any time (P > 0.05); whereas, tPA was greater in control follicles at 114 hr after PMSG than in manipulated follicles (P < 0.01). The effect of pyrilamine, a histamine-1 receptor antagonist, on tPA concentrations was determined in manipulated and control follicles collected at 3, 12, 24, 42, and 66 hr after manipulation. Concentrations of tPA were similar in control and manipulated follicles for gilts treated with pyrilamine, but again control follicles had greater (P < 0.05) tPA concentrations at 114 hr after PMSG. Thus, tPA seems to be involved in ovulation, and blockage of ovulation and subsequent cyst formation results from inadequate tPA activity in manipulated follicles.

Factors contributing to the formation of experimentally-induced ovarian cysts in prepubertal gilts.

Manipulation of an ovary during the follicular phase in cycling gilts or prepubertal gilts treated with PMSG and hCG results in formation of cysts on manipulated ovaries and corpora lutea (CL) of normal appearance on nonmanipulated ovaries. In contrast, cysts did not form after manipulation in luteal phase gilts. In the present experiment, daily administration of 50 mg progesterone to prepubertal gilts treated with PMSG and hCG established luteal phase concentrations of progesterone but did not lessen the incidence of manipulated-induced cysts. Number of cysts formed was associated with the number of follicles > or = 5 mm at manipulation, which was inversely related to serum concentrations of progesterone. Number of receptors for LH/hCG in follicular tissues did not differ between manipulated and nonmanipulated ovaries but was greater in granulosa (P < .05) and theca (P < .08) from follicles with diameters > or = 7 mm compared to 5 and 6 mm. Contents of estradiol, androstenedione, testosterone, progesterone and prostaglandins E2 and F2 alpha in follicular fluid, granulosa and theca were not different between follicles > or = 5 mm destined to form cysts. Profiles of progesterone and estradiol in peripheral serum and duration of luteal phase concentrations of progesterone were not different for gilts with induced cysts and gilts with CL. In conclusion, manipulation of follicles resulted in a failure to ovulate. Subsequent formation of cysts did not result from or result in a loss of steroidogenic function or the ability to bind LH to follicular receptors. These results demonstrate that the mechanism for ovulation is independent of other follicular processes, since ovulation can be disrupted without altering follicular steriodogenesis or subsequent luteinization.

Catheterization of the caudal vena cava via the lateral saphenous vein in the ewe, cow, and gilt: an alternative to utero-ovarian and medial coccygeal vein catheters.

Current methods for obtaining venous blood from the reproductive organs of livestock often have a low rate of success or involve intensive surgical procedures that may impair ovarian function. Therefore, the caudal vena cava was catheterized via the lateral saphenous vein to determine the feasibility of using this method for chronic sampling of blood draining from the reproductive organs of ewes (n = 6), cows (n = 6), and gilts (n = 7). Blood samples were collected at 2-cm (ewes and gilts) or 5-cm (cows) intervals during insertion of catheters. Correct placement, defined as the position at which plasma concentrations of progesterone or estrogen were at least threefold greater than in jugular venous plasma, varied among species and among animals within species. It seemed, however, that a majority of catheters would be placed correctly if secured at 48 to 52 cm in ewes, 52 cm in gilts, and 90 to 100 cm in cows. Saphenous vein catheters were secured for sequential sampling of vena caval blood during the follicular phase of ewes (n = 25), cows (n = 4), and gilts (n = 5). Catheters remained patent for the duration of sampling in all individuals. Concentrations of estrogen in jugular and vena caval plasma were correlated (ewe P less than .0003; cow P less than .0001; gilt P less than .0001). Profiles of progesterone and estrogen revealed an episodic pattern of secretion in vena caval but not jugular plasma. Catheterization of the vena cava via the saphenous vein is a relatively simple and noninvasive method for obtaining blood containing uterine and ovarian hormones before their metabolism.

Activation of 5-HT1A receptors in medullary raphé disrupts sleep and decreases shivering during cooling in the conscious piglet.

Activation of 5-HT1A receptors in the medullary raphé decreases sympathetically mediated brown adipose tissue (BAT) thermogenesis and peripheral vasoconstriction when previously activated with leptin, LPS, prostaglandins, or cooling. It is not known whether shivering is also modulated by medullary raphé 5-HT1A receptors. We previously showed in conscious piglets that activation of 5-HT1A receptors with (+/-)-8-hydroxy-2-(dipropylamino)-tetralin (8-OH-DPAT) in the paragigantocellularis lateralis (PGCL), a medullary region lateral to the raphé that contains substantial numbers of 5-HT neurons, eliminates rapid eye movement (REM) sleep and decreases shivering in a cold environment, but does not attenuate peripheral vasoconstriction. Hoffman JM, Brown JW, Sirlin EA, Benoit AM, Gill WH, Harris MB, Darnall RA. Am J Physiol Regul Integr Comp Physiol 293: R518-R527, 2007. We hypothesized that, during cooling, activation of 5-HT1A receptors in the medullary raphé would also eliminate REM sleep and, in contrast to activation of 5-HT1A receptors in the PGCL, would attenuate both shivering and peripheral vasoconstriction. In a continuously cool environment, dialysis of 8-OH-DPAT into the medullary raphé resulted in alternating brief periods of non-REM sleep and wakefulness and eliminated REM sleep, as observed when 8-OH-DPAT is dialyzed into the PGCL. Moreover, both shivering and peripheral vasoconstriction were significantly attenuated after 8-OH-DPAT dialysis into the medullary raphé. The effects of 8-OH-DPAT were prevented after dialysis of the selective 5-HT1A receptor antagonist WAY-100635. We conclude that, during cooling, exogenous activation of 5-HT1A receptors in the medullary raphé decreases both shivering and peripheral vasoconstriction. Our data are consistent with the hypothesis that neurons expressing 5-HT1A receptors in the medullary raphé facilitate spinal motor circuits involved in shivering, as well as sympathetic stimulation of other thermoregulatory effector mechanisms.

Activation of 5-HT1A receptors in the paragigantocellularis lateralis decreases shivering during cooling in the conscious piglet.

Activation of 5-HT(1A) receptors in the medullary raphé decreases sympathetic outflow to thermoregulatory mechanisms, including brown adipose tissue (BAT), thermogenesis, and peripheral vasoconstriction when these mechanisms are previously activated with leptin, prostaglandins, or cooling. These same mechanisms are also inhibited during rapid eye movement (REM) sleep. It is not known whether shivering is also modulated by medullary raphé neurons. We previously showed in the conscious piglet that activation of 5-HT(1A) receptors with 8-OH-DPAT (DPAT) in the paragigantocellularis lateralis (PGCL), a medullary region lateral to the midline raphé that contains 5-HT neurons, decreases heart rate, body temperature and muscle activity during non-rapid eye movement (NREM) sleep. We therefore hypothesized that activation of 5-HT(1A) receptors in the PGCL would also attenuate shivering and peripheral vasoconstriction during cooling. During REM sleep in a cool environment, shivering, carbon dioxide production, and body temperature decreased, and ear capillary blood flow and ear skin temperature increased. Shivering associated with rapid cooling was attenuated after dialysis of DPAT into the PGCL. In animals maintained in a continuously cool environment, dialysis of DPAT into the PGCL attenuated shivering and decreased body temperature, but there were no significant increases in ear capillary blood flow or ear skin temperature. We conclude that both naturally occurring REM sleep and exogenous activation of 5-HT(1A) receptors in the PGCL are associated with a suspension of shivering during cooling. Our data are consistent with the hypothesis that 5-HT neurons in the PGCL facilitate oscillating spinal motor circuits involved in shivering but are less involved in modulating sympathetically mediated thermoregulatory mechanisms.

Differential effects of pulsatile versus continuous follicle-stimulating hormone delivery on the production of cyclic adenosine 5'-monophosphates and the accumulation of cytochrome P450 cholesterol side-chain cleavage enzyme mRNA in perifused porcine granulosa cells.

Although administration of FSH to porcine granulosa cells in static primary cultures increased accumulation of cAMP in the culture medium and cytochrome P450 cholesterol side chain cleavage enzyme (SCC) mRNA in the cells, the importance of the physiologically pulsatile pattern of FSH secretion in regulating the expression of specific genes required for ovarian steroidogenesis is unknown. To evaluate the impact of the mode of FSH delivery on ovarian target cell responses, we examined cAMP production and SCC mRNA accumulation in granulosa cells perifused with continuous or pulsatile FSH stimuli. Porcine granulosa cells were plated onto Cytodex 3 microcarrier beads, placed into perifusion columns, and perifused at 25 or 37 degrees C with 190 microliters/min Eagle's minimum essential medium (MEM) or MEM containing 100 ng/ml ovine (o) FSH delivered continuously, or 100 or 600 ng/ml oFSH delivered in 15-min pulses every 90 or 180 min. After perifusion, total RNA was isolated from granulosa cells for Northern analysis of specific SCC mRNA normalized to the constitutively expressed cyclophilin mRNA. Cyclic AMP in control columns remained basal throughout the perifusion. In contrast, cAMP increased 10- to 15-fold within 30-50 min of the onset of tonic FSH delivery. This increase in cAMP was maintained at 25 degrees C, but gradually decreased to a 2-fold increase in columns perifused at 37 degrees C. Release of cAMP increased 5- to 7-fold in response to 100 ng/ml oFSH pulses given at 90 or 180 min intervals, and 15- to 20-fold in response to 600 ng/ml oFSH pulses, and decreased to near control levels between FSH pulses.(ABSTRACT TRUNCATED AT 250 WORDS)

Communities play key role in extending public health insurance to children.

Nearly all low-income children are now eligible for public health insurance coverage through Medicaid or the State Children's Health Insurance Program (SCHIP), but millions of eligible children still lack coverage. Increasingly, states have turned to local communities to assist with SCHIP outreach. The Center for Studying Health System Change's (HSC) recent site visits to 12 nationally representative communities found many organizations not traditionally involved in public health insurance activities--such as schools, employers and religious and community groups--playing important outreach roles. Local social service agencies, health departments and providers also are helping children gain coverage. For policy makers seeking to increase enrollment, these community efforts offer a valuable road map. Local SCHIP outreach generally is considered successful but is costly. And, state budget shortfalls and reduced federal SCHIP funding could threaten outreach efforts.

Linear dichroism of the retinal nerve fiber layer expressed with Mueller matrices.

An electro-optic device is used that permits the measurement of polarized absorption spectra (linear dichroism). The change of the polarization state of a light beam brought about by passage through the optic elements of a dichrograph are described mathematically by a transformation of the Stokes vector. The polarization or absorption properties of the optical elements are described by the Mueller matrices. The dichroic properties of sheep retina and cornea are studied in vitro.

Coordinate developmental expression of genes regulating sterol economy and cholesterol side-chain cleavage in the porcine ovary.

To investigate the coordinate developmental expression of low-density lipoprotein (LDL) receptor, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, sterol carrier protein 2 (SCP2), steroidogenic acute regulatory protein (StAR), and cytochrome P450 side-chain cleavage (P450scc) enzyme messages throughout the pig estrous cycle, RNase protection analysis was performed using homologous (partially cloned) porcine sequences. Total RNA was isolated from ovarian tissues from unstimulated prepubertal gilts and gilts stimulated with eCG (Day -3) and hCG (Day 0) to induce follicular growth and ovulation. Specific transcripts (relative to 18S rRNA) were quantified in immature ovaries, preovulatory follicles (> or = 5 mm), corpora lutea (CL), and corpora albicantia. As an index of steroidogenesis, tissue progesterone content (per microgram protein) was low in the unstimulated ovary and preovulatory follicles, and it began to increase 4 days post-hCG, peaked at 12 days, and returned to preovulatory concentrations by 20 days post-hCG. HMG-CoA reductase mRNA was expressed at low levels and did not change significantly throughout the estrous cycle. The amount of LDL receptor mRNA increased approximately 6-fold after eCG stimulation and was expressed at similar concentrations in both preovulatory follicles and functional CL. Expression of SCP2 mRNA did not differ among the four tissue types but tended to be highest in midcycle (Day 12) CL compared other stages of CL (p = 0.007). StAR mRNA expression was minimal in unstimulated ovaries, was higher in preovulatory follicles (p = 0.014), and then rose again in CL (p = 0.009 compared with unstimulated ovary). P450scc mRNA concentrations were low in unstimulated ovaries, increased in preovulatory follicles (p = 0.044), and increased further in CL (p = 0.001 compared with preovulatory follicles). P450scc and StAR mRNA levels correlated with progesterone levels (r = +0.37, p = 0.025, and r = +0.71, p < 0.001, respectively). The expression of LDL receptor, StAR, and P450scc messages showed a dramatic decline by Day 20 post-hCG (p = 0.002, p = 0.003, p = 0.006, respectively, compared with CL) corresponding with functional regression of the CL. In summary, P450scc and StAR message expression are coordinately amplified during the pig follicular and luteal phase, whereas LDL receptor message after an initial increase is expressed at constitutively high levels, thus indicating a differential regulation of ovarian sterol-metabolizing genes during the steroidogenic life of the follicle and CL.

Effect of oral 13-cis-retinoic acid at three dose levels on sustainable rates of sebum secretion and on acne.

Changes in sustainable rates of sebum secretion were followed in twenty patients with severe acne who were receiving oral treatment with 13-cis-retinoic acid in dosages of 0.1, 0.5, or 1.0 mg/kg/day. Sebum secretion was measured by absorption of skin surface lipid into bentonite clay and estimation of the amount of absorbed sebum by measurement of its wax ester component. Pretreatment rates of sebum secretion in the patients were greatly elevated in comparison with previously measured values in young adult subjects without acne. After 4 weeks of treatment, mean rates of sebum secretion on all three dose levels fell to or below the range for normal subjects. On-treatment rates of sebum secretion were significantly lower in patients on the highest dose compared to patients on the lowest dose. When the drug was discontinued, rates of sebum secretion recovered slowly. Clinical response was excellent in most of the subjects. The five subjects with least favorable response clinically all had better than average suppression of sebum production.