Influence of environmental variability and Emiliania huxleyi ecotypes on alkenone-derived temperature reconstructions in the subantarctic Southern Ocean

Long-chain unsaturated alkenones produced by haptophyte algae are widely used as paleotemperature indicators. The unsaturation relationship to temperature is linear at mid-latitudes, however, non-linear responses detected in subpolar regions of both hemispheres have suggested complicating factors in these environments. To assess the influence of biotic and abiotic factors in alkenone production and preservation in the Subantarctic Zone, alkenone fluxes were quantified in three vertically-moored sediment traps deployed at the SOTS observatory (140°E, 47°S) during a year. Alkenone fluxes were compared with coccolithophore assemblages, satellite measurements and surface-water properties obtained by sensors at SOTS. Alkenone-based temperature reconstructions generally mirrored the seasonal variations of SSTs, except for late winter when significant deviations were observed (3-10 °C). Annual flux-weighted averages in the 3800 m trap returned alkenone-derived temperatures ~1.5 °C warmer than those derived from the 1000 m trap, a distortion attributed to surface production and signal preservation during its transit through the water column. Notably, changes in the relative abundance of E. huxleyi var. huxleyi were positively correlated with temperature deviations between the alkenone-derived temperatures and in situ SSTs (r = 0.6 and 0.7 at 1000 and 2000 m, respectively), while E. huxleyi var. aurorae, displayed an opposite trend. Our results suggest that E. huxleyi var. aurorae produces a higher proportion of C_37:3 relative to C_37:2 compared to its counterparts. Therefore, the dominance of var. aurorae south of the Subtropical Front could be at least partially responsible for the less accurate alkenone-based SST reconstructions in the Southern Ocean using global calibrations. However, the observed correlations were largely influenced by the samples collected during winter, a period characterized by low particle fluxes and slow sinking rates. Thus, it is likely that other factors such as selective degradation of the most unsaturated alkenones could also account for the deviations of the alkenone paleothermometer.

Melatonin administration during the dry period stimulates subsequent milk yield and weight gain of offspring in subtropical does kidding in summer

In the present experiment, we tested the hypothesis that in does kidding in summer, melatonin administration during dry period is galactopoietic for the subsequent lactation and results in improved growth of their suckling kids. Twenty-five multiparous pregnant creole does were enrolled into a randomized complete block design during their dry period in the 49 d prepartum, and under natural long photoperiods around the summer solstice, pregnant does either received 2 subcutaneous ear implants (18 mg) of melatonin (MEL, n = 10) or served as nonimplanted controls (CONT, n = 15). During the first 14 wk of subsequent lactation (suckling and milking periods), MEL does yielded more milk than CONT does. Throughout subsequent lactation, milk composition was not affected by treatment. In MEL does, peripheral triiodothyronine levels peaked at 2 wk of lactation, remaining higher than in CONT does. The mean daily weight gain was higher in MEL compared with CONT kids and was also higher in males than females, and for males, was positively correlated with milk yield. The current data support our hypothesis that melatonin during the prepartum period is galactopoietic in suckling does.

Subtropical goats ovulate in response to the male effect after a prolonged treatment of artificial long days to stimulate their milk yield

The objectives of this study were to determine (i) if in subtropical goats that gave birth during mid-December, the exposition to an artificial long-day photoperiod consisting in only 14 hr of light per day can increase the milk yield and (ii) to test whether these females can respond to the male effect at the end of the prolonged photoperiodic treatment. In experiment 1, 17 lactating goats were maintained under natural short days (control group), while another 22 goats were maintained under artificial long days (treated group) consisting in 14 hr light and 10 hr darkness starting at day 10 of lactation. The continuous exposition to an artificial long-day photoperiod produced an increase in the milk yield level during the first 110 days of lactation (time × treatment interaction; p = .01), while none of the milk components were modified due to the photoperiodic treatment (p > .05). In experiment 2, all control and treated anovulatory goats were submitted to the male effect using photostimulated males. All females showed oestrous behaviour within the first 10 days that were in contact with males (100% in both groups; p > .05). Thus, the latency to onset of oestrus did not differ between females from control (58.2 ± 3.0 hr) and treated (62 ± 4.6 hr) groups. Male exposition provoked ovulation independently if females were previously under long days or natural photoperiod (96 vs 100%, respectively; p = .79). It was concluded that exposure to 14 hr of light per day in subtropical goats that gave birth in late autumn stimulates milk yield without preventing the ovulation in response to the male effect at the end of the prolonged photoperiodic treatment.

Locating the critical end point using the linear sigma model coupled to quarks

We use the linear sigma model coupled to quarks to compute the effective potential beyond the mean field approximation, including the contribution of the ring diagrams at finite temperature and baryon density. We determine the model couplings and use them to study the phase diagram in the baryon chemical potential-temperature plane and to locate the Critical End Point.

In vitro progesterone production by luteinized human mural granulosa cells is modulated by activation of AMPK and cause of infertility

BACKGROUND

Mural granulosa cells from IVF patients were provided by the West Virginia University Center for Reproductive Medicine in Morgantown, WV. The effect of adenosine monophosphate activated protein kinase (AMPK) activation, primary cause of infertility, age, BMI, and pregnancy outcome on production of progesterone were examined separately.

METHODS

Isolated mural sheets from IVF patients (n = 26) were centrifuged, supernatant discarded, and the pellet re-suspended in 500 μl of DMEM/F12. Mural granulosa cells were plated at 10,000 cells/well in triplicate per treatment group with 300 μl DMEM/F12 media at 37 °C and 5% CO2 in a humidified incubator to permit luteinization. Four days after initial plating, cells were treated with either an AMPK inhibitor, DM; an AMPK activator, AICAR; or hCG. Cells were cultured for 24 h after treatment when medium was collected and frozen at -20 °C until assayed for P4 by radioimmunoassay.

RESULTS

The AMPK activator, AICAR, inhibited P4 production (P < 0.001), whereas the AMPK inhibitor, DM, did not affect basal P4 (P < 0.05). Progesterone production increased when cells from patients whose primary cause of infertility was a partner having male infertility were treated with hCG compared to control (P = 0.0045), but not in patients with other primary infertility factors (P > 0.05). Additionally, hCG increased P4 production in patients between the ages 30-35 (P = 0.008) and 36-39 (P = 0.04), but not in patients ages 25-29 (P = 0.73). Patients with normal BMI had increased P4 production when treated with hCG (P < 0.0001), however there was no change in P4 production from cells of patients who were overweight or obese (P > 0.05). Cells from patients who became pregnant to IVF had greater P4 production when stimulated with hCG than those who did not become pregnant when compared to controls (P > 0.05).

CONCLUSIONS

Understanding how AMPK activation is regulated in ovarian cells could lead to alternative or novel infertility treatments. Human mural granulosa cells can serve as a valuable model for understanding how AMPK affects P4 production in steroidogenic cells. Additionally, when stimulated with hCG, P4 production by mural granulosa cells differed among infertility type, age, BMI, and pregnancy outcome.

Sexually active males prevent the display of seasonal anestrus in female goats

A well-defined season of sexual rest controlled by photoperiod is observed in female sheep and goats during spring and summer, delineating their "anestrous season"; bucks also decrease sexual activity at about the same time. Nutrition and/or socio-sexual stimuli play only secondary roles. However, the presence of sexually active males can reduce the length of seasonal anestrus. Whether it can also completely suppress anestrus has not been investigated. Here we tested this in goats in 3 experiments, using bucks rendered sexually active out of season by exposure to long days. The continuous presence of these males prevented goats to display seasonal anestrus: 12/14 females cycled the year round, vs. 0/13 and 0/11 for females with un-treated bucks or without bucks (experiment 1). When active bucks were removed, females immediately entered anestrus (7/7 stopped ovulating vs. 1/7 if maintained with active bucks; experiment 2). Finally, 7/7 anestrous does with bucks in sexual rest since 1.5months commenced cycling rapidly during mid-anestrous, when these bucks became sexually active following a treatment with artificial long days, vs. 0/7 with un-treated bucks or no bucks (experiment 3). The presence/withdrawal of active bucks had a highly significant effect in the three experiments (P≤0.002). Therefore, the presence of a mating opportunity can completely override the photoperiodic inhibition of reproduction of females throughout the anestrous season. Results suggest that we must re-evaluate the relative contributions of photoperiod vs. other external cues in controlling seasonal reproduction, thus offering new non-pharmaceutical ways for controlling out-of-season reproduction in small ruminants.

Importance of intense male sexual behavior for inducing the preovulatory LH surge and ovulation in seasonally anovulatory female goats

The present study was carried out to determine whether the presence of photostimulated sedated male goats could stimulate the LH preovulatory surge and ovulation in seasonal anestrous goats. Sexually experienced male goats were treated with artificial long days (16 hours light per day) from 1 November to 15 January to stimulate their sexual activity in March and April, corresponding to the natural sexual rest. A female group of goats (n=20) was exposed to non-sedated males who displayed an intense sexual behavior and provided strong odor (non-sedated group). Another female group of goats (n=20) was exposed to the photo-stimulated male goats, but these males were sedated with Xylazine 2% to prevent the expression of sexual behavior (sedated group). The sedated males also provided a strong odor. Females of both groups had full physical and visual contact with non-sedated or sedated males. In both groups, the males remained with females during 4 days. The LH preovulatory surge of 10 female goats per group was measured by determination of LH plasma concentrations in samples taken every 3 hours. In addition, in all goats, (n=20 by group), ovulation was determined by measuring plasma concentrations of progesterone. The proportion of female goats showing a preovulatory LH surge was higher in goats exposed to non-sedated (10/10) than in those exposed to sedated bucks (0/10; P<0.0001). Similarly, most of does in contact with non-sedated males ovulated (19/20), but none of those in contact with sedated males did so (0/20; P<0.0001). We conclude that the expression of an intense sexual behavior by male goats is necessary to induce LH preovulatory surge and ovulation in seasonally anovulatory goats.

Two or 24 h of daily contact with sexually active males results in different profiles of LH secretion that both lead to ovulation in anestrous goats

Two experiments were conducted to (a) determine whether sexually active males are able to stimulate the sexual activity of anestrous female goats when duration of contact is reduced to an intermittent contact shorter than 4 daily hours and (b) compare the pattern of secretion of LH when anestrous goats are exposed either permanently or intermittently to males. In the first experiment, 4 groups of anovulatory goats were exposed to sexually active males for 24, 4, 2, or 1 h/d during 15 consecutive days, whereas control females remained isolated. More than 89% of females in the groups exposed to the sexually active bucks ovulated, whereas only 5% did so in the control group (P < 0.001). However, the proportion of females ovulating before day 4 was greater in the 2-, 4-, or 24-h contact groups than in the control, whereas it did not differ between the control group and the 1-h contact group (P = 0.02, <0.001, <0.001 and 0.23, respectively). In the second experiment, 3 groups of anovulatory goats were exposed permanently (24 h/d) or intermittently (2 h/d) to bucks during 5 d or remained isolated. We found that pulsatility of luteinizing hormone (LH) increased in the intermittent and permanent contact groups after males were introduced to females (P = 0.05); this pulsatility of LH remained elevated in the permanent-contact group, whereas it decreased in the intermittent-contact group, once the male was removed (P = 0.32 and 0.05, respectively). We conclude that 1 or 2 daily hours of contact with sexually active males is sufficient to stimulate ovulatory activity in anovulatory goats; however, ovulation is obtained through a different pattern of secretion of LH.

Artificial long-day photoperiod in the subtropics increases milk production in goats giving birth in late autumn

Two experiments were conducted to determine whether exposure to a photoperiod of artificial long days in autumn increased milk yield in subtropical goats milked once (Exp. I) or twice daily (Exp. II). In Exp. I, starting at d 10 of lactation, 1 group of does was kept under naturally decreasing photoperiod (DD1X; n = 8), whereas the other group was submitted to an artificial photoperiod of long days (LD1X; n = 8; 16 h light:8 h darkness). The kids were weaned 28 d after parturition, and dams were manually milked once daily. Milk yield and milk components (fat, protein, and lactose) were assessed up to 140 d of lactation. From d 0 to 28 of lactation (suckling phase), mean daily milk yield did not differ between DD1X and LD1X goats (2.3 ± 0.2 kg vs. 2.4 ± 0.2 kg; P = 0.717). However, between d 29 and 84 (early milking phase), mean daily milk yield was greater in LD1X does than in DD1X does (2.6 ± 0.1 kg vs. 2.1 ± 0.1 kg; P = 0.001). Finally, between d 85 and 140 (late milking phase), mean daily milk yield was greater in LD1X goats than in DD1X goats (P ≤ 0.05) only during the first 2 wk. In Exp. II, one group of goats was exposed to a photoperiod of naturally decreasing days (DD2X; n = 8) and another group was submitted to an artificial photoperiod of long days (LD2X; n = 7). In both groups, kids were weaned on d 28 of lactation and the dams were manually milked twice daily. During the nursing phase, mean daily milk yield did not differ between the DD2X and LD2X groups (2.5 ± 0.3 kg vs. 2.6 ± 0.2 kg; P = 0.767). In the early milking phase, mean daily milk yield was greater in LD2X than in DD2X goats (3.3 ± 0.2 kg vs. 2.8 ± 0.2 kg; P = 0.022), whereas during the late milking phase, milk yield did not differ between the 2 groups (P = 0.946). In both experiments, milk composition was not significantly influenced by exposure to long-day photoperiod. We conclude that, in subtropical female goats that start lactation in late autumn, exposure to an artificial long-day photoperiod stimulates milk yield, even if goats are milked once daily. In addition, combining exposure to long days with twice-daily milking will increase further milk yield in such goats without affecting milk components.

Four hours of daily contact with sexually active males is sufficient to induce fertile ovulation in anestrous goats

The study was conducted on two consecutive years to determine whether ovulatory activity can be induced in anovulatory goats by exposing them to sexually active bucks for 4, 8, 12 or 16 h per day during 15 consecutive days. In experiment 1, females remained continuously in the experimental pens where they were in contact with males. One group remained isolated from males (controls) and four other groups were exposed to sexually active males for 4, 8, 12 or 16 h per day. In experiment 2, females were taken away to "resting" pens free of male odours between the periods of contact with bucks. They were allocated to 5 groups as in experiment 1. Ovulations were determined by progesterone plasma levels and transrectal ultrasonography. Pregnancy was determined by abdominal ultrasonography. In both experiments, more than 90% of females exposed to the bucks had at least one ovulation during the whole experiment whereas only 11 or 0% (experiments 1 and 2, respectively) did so in the control group (P<0.001). Furthermore, the proportion of females ovulating did not differ among groups depending on duration of contact with bucks (P>0.05). In both experiments, pregnancy rates were not affected by the daily duration of contact with males (P>0.05). To conclude, 4h of daily contact with sexually active males is sufficient to stimulate ovulatory activity in anovulatory goats and this effect is not due to the presence of olfactory cues from the males remaining in the pens.

Reproductive seasonality in female goats adapted to a subtropical environment persists independently of food availability

The aim of this study was to determine whether the seasonal change in food availability provides a predictive cue that synchronizes the breeding season in goats adapted to the subtropical conditions of Northern Mexico. Groups of multiparous intact (n=7) and ovariectomized does bearing a subcutaneous implant constantly releasing estradiol-l7 beta (OVX+E; n=12) were allocated in two pens and received a constant amount of feed. Another group of OVX+E does (n=10) was incorporated into a flock raised under natural grazing conditions with seasonal fluctuations in food availability. Blood samples were taken twice weekly. Ovulation of intact goats was inferred from plasma progesterone levels. In OVX+E does plasma levels of LH were measured. Intact does displayed seasonal variations in ovulation and the breeding season lasted from September to February. OVX+E goats displayed large seasonal variations in LH secretion regardless of whether they were fed constantly indoors or kept under natural grazing conditions (P<0.0001). The mean date of increase in LH secretion varied between years (P<0.0001) but did not differ between groups (naturally grazed: August 13+/-10 days; constantly fed: August 26+/-10 days). In contrast, the seasonal decline in LH secretion differed between groups: it was consistently delayed in constantly fed animals compared to those feeding naturally (naturally grazed: January 28+/-4 days; constantly fed: February 24+/-6 days, group effect, P<0.01). These results show that local female goats from subtropical Mexico display large reproductive seasonality independently of food availability.

Prevalence of autoimmune thyroid disorders in a Spanish multiple sclerosis cohort

The aim of the study was to determine the prevalence of thyroid autoimmune disorders in a cohort of untreated multiple sclerosis (MS) patients and compare it with a stratified sample of an adult population. We prospectively studied 93 untreated MS patients. The control group included 401 healthy subjects selected by stratified sampling in a non-iodine-deficient area. Antithyroid antibodies (ATA) (antibodies against peroxidase and thyroglobulin) were considered positive at titres > or =149 IU/ml. Antibodies were positive in 11 MS patients (11.8%; 95% CI 5.3-18.4%). This prevalence was five times higher (P = 0.0001) when compared with that in the control population. We found six cases with subclinical hypothyroidism (6.45%; 95% CI 11.4-1.5) in contrast to 2.24% in the control group. Comparing MS with positive and negative ATA, there was a non-significant, slightly higher frequency of low Expanded Disability Status Scale (EDSS) score in the ATA-positive group (81% vs. 73.2%). One year after start of interferon (IFN) treatment, only one patient developed subclinical thyroid dysfunction. MS patients have a higher prevalence of ATA compared with the general population. An initial ATA and thyroid-stimulating hormone (TSH) determination is recommended in all MS patients. A periodic assessment of thyroid function during IFN treatment only seems to be justified in those cases where positive ATA or dysfunction is present before treatment.

[Natural "dopaminotrophic" cell transplant: a new concept in antiparkinsonian therapy]

AIM AND METHOD

Parkinson s disease is caused by the degeneration of dopaminergic neurons of substantia nigra projecting to striatum. Cellular substitution represents a potentially treatment once beneficial levodopa effects wear off. A promising therapeutic approach is grafting cells or other vectors which release neuroprotective molecules that stimulate regeneration in the damaged nigrostriatal system or, in other words, that exert a dopaminotrophic action. We have tested the suitability of intrastriatal grafts of extra adrenal chromaffin cells taken from the Zuckerkandl s organ. This paraganglion contains chromaffin cells that express and release glial cell line derived neurotrophic factor (GDNF) and transforming growth factor b1 (TGF b1), both known to protect dopamine cells in vitro and in vivo. Grafts induced a functional recovery of parkinsonian rats which developed over months. The beneficial effects of grafts of the Zuckerkandl s organ were related to long survival of grafted cells, striatal reinnervation, enhancement of dopamine levels in the host striatum, and the cell delivery into the host striatum of GDNF and TGF b1.

CONCLUSION

Our result should stimulate research on the clinical applicability of transplants of the Zuckerkandl s organ in Parkinson s disease

Induction of sexual activity in lactating anovulatory female goats using male goats treated only with artificially long days

Two experiments were conducted to determine the response of Creole male goats treated with long days and melatonin implants, and the response of the anovulatory does to male effect using males treated only with artificially long days. All animals were allocated to open sheds. In Exp. 1, one group of males was under natural photoperiod (CG; n = 7); the second group was submitted to 2.5 mo of long days followed by the insertion of two s.c. melatonin implants (LD+MEL; n = 7); the third group was subjected only to 2.5 mo of long days (LD; n = 7). Testicular weight was measured every 2 wk. Plasma testosterone concentrations were determined weekly. A treatment x time interaction was detected (P < 0.001) for testicular weight and plasma testosterone concentration. In the LD+MEL and LD groups, testicular size and plasma testosterone levels varied in a similar way, but differed from those observed in CG (P < 0.001). In this latter group, testicular weight displayed seasonal variations and peaked in June, whereas in treated groups this peak occurred in March. In CG, testosterone varied in a seasonal manner and plasma concentrations increased in June and remained elevated throughout the study. In experimental groups, testosterone increased in February and peaked in March. In Exp. 2, one group of males was left under natural photoperiod (CG, n = 5) and the other one was submitted to 2.5 mo of artificially long days (LD, n = 4). On March 16, two control and two treated males were put in contact with 20 and 19 females, respectively. Sexual behavior of the bucks was observed during the 5 d following male introduction. Progesterone assays and estrous behavior were used to determine ovarian and behavioral responses of the females to teasing. The anogenital sniffing, nudging, and mount instances registered in LD-treated males were greater than those observed in CG (P < 0.05). Of the does exposed to CG, none ovulated and only two of 20 females displayed estrous behavior. All does in contact with LD-treated males ovulated and showed at least one estrous behavior during the 15 d following joining (P < 0.001). These results indicate that the sexual activity of male goats from subtropical latitudes can be induced using only artificially long days. In addition, males treated in this way are capable of stimulating sexual activity in anovulatory females by the male effect.

Combined spinal and epidural anesthesia for abdominal aortic aneurysm surgery in patients with severe chronic pulmonary obstructive disease

BACKGROUND

The presence of chronic obstructive pulmonary disease (COPD) should not be considered a contraindication to operation but should rather identify those patients that require special preoperative and postoperative pulmonary care. The purpose of this paper is to report our experience in the use of combined spinal and epidural anesthesia (CSEA) for open AAA repair in such patients.

METHODS

From April 1997 to November 1998, three patients with severe COPD underwent elective open infrarenal AAA repair under CSEA. All the patients satisfied one or more of the following criteria: a room air PaO2 =or<60 mmHg, PaCO2 =or>45 mmHg, FEV1 =or<50% of predicted, and/or FVC =or<75% of predicted, and one of them was on home oxygen preoperatively. Preoperative preparation of the patients consisted of breathing exercises with incentive espirometry, elimination of underlaying pulmonary infections and usage of bronchodilator therapy.

RESULTS

All the patients tolerated surgery safely. None of them developed postoperative complications, including pneumonia and other respiratory conditions. No significant changes in room air arterial blood gas or pulmonary function was recognized before and after surgery.

CONCLUSIONS

CSE anesthesia is a viable anesthetic option for conventional AAA surgery in patients with severe COPD since it can preserve spontaneous breathing and provide additional respiratory benefits over general anesthesia.

Popliteal venous aneurysms: involvement of tibial nerve in aneurysmal wall

Primary popliteal venous aneurysms are very rare vascular abnormalities, with 50 cases reported in the English literature. Thromboembolic complications are common in popliteal venous aneurysms. Since medical treatment has been proved inadequate, surgical repair is recommended with a minimum time delay. However, it involves some risk because of the complex anatomy of the popliteal space. We report on a case of popliteal venous aneurysm, in which the tibial nerve was involved in the aneurysmal wall and was injured by surgical repair.

A Mathematical Model for the Dynamics of Hepatitis C

We formulate a model to describe the dynamics of hepatitis C virus (HCV) considering four populations: uninfected liver cells, infected liver cells, HCV and T cells. Analysis of the model reveals the existence of two equilibrium states, the uninfected state in which no virus is present and an endemically infected state, in which virus and infected cells are present. There exists a threshold condition that determines the existence and stability of the endemic equilibrium. We discuss the efficacy of the therapy methods for hepatitis C in terms of the threshold parameter. Success of the therapy could possibly be predicted from the early viral dynamics in the patients.

Functional regeneration in a rat Parkinson's model after intrastriatal grafts of glial cell line-derived neurotrophic factor and transforming growth factor beta1-expressing extra-adrenal chromaffin cells of the Zuckerkandl's organ

Intrabrain transplantation of chromaffin cell aggregates of the Zuckerkandl's organ, an extra-adrenal paraganglion that has never been tested for antiparkinsonian treatment, induced gradual improvement of functional deficits in parkinsonian rats. These beneficial effects were related to long survival of grafted cells, striatal reinnervation, and enhancement of dopamine levels in grafted striatum. Grafted cells were not dopaminergics, but they expressed glial cell line-derived neurotrophic factor (GDNF) and transforming growth factor-beta(1). These factors were detected in the host striatal tissue, indicating that chromaffin cells secreted them after grafting. Because glial cell line-derived neurotrophic factor possesses neurorestorative properties over dopaminergic neurons, and transforming growth factor-beta(1) is a cofactor that potentiates the neurotrophic actions of GDNF, functional regeneration was likely caused by the chronic trophic action of neurotrophic factors delivered by long-surviving grafted cells. This work should stimulate research on the clinical applicability of transplants of the Zuckerkandl's organ in Parkinson's disease.

Prostaglandin F(2alpha) regulation of the bovine corpus luteum endothelin system during the early and midluteal phase

Recent evidence in the cow suggests that endothelin-1 (ET-1) plays a role during prostaglandin (PG) F(2alpha)-induced luteal regression. We have examined the effects of treatment with PGF(2alpha) during the early and midluteal phases on three components of the endothelin system: endothelin-converting enzyme-1 (ECE-1), ET type A receptor (ET(A)), and ET-1 in the bovine corpus luteum (CL). Cyclic beef cows were injected (0 h) on Day 4 or 10 with either saline or the PGF(2alpha) analogue Lutalyse (15 mg). The CL were collected at 2 (n = 11), 10 (n = 23), 24 (n = 15), or 48 h (n = 12) after treatment. The cows in which CL were removed after 10 h comprised of two experimental groups. The first group (n = 11) received one injection; the second group (n = 12) received two injections, one at 0 h and one at 8 h. The cows in which CL were collected after 24 and 48 h received one injection every 8 h. Semiquantitative reverse transcriptase-polymerase chain reaction was used to evaluate the mRNA encoding ECE-1, ET(A), and ET-1. The ECE-1 and ET(A) proteins were evaluated by semiquantitative Western blot analysis. The ET-1 was the most likely component of the endothelin system target for PGF(2alpha) regulation during the midluteal phase. The ET(A) and ECE-1 genes were constitutively expressed in the Day 4 and Day 10 CL. A practical application of this observation is that it may be possible to target the ET-1 gene as a way to manipulate the luteolytic action of PGF(2alpha).

Gene expression of endothelin-1 in the porcine ovary: follicular development

We have investigated which follicular compartment and stage of follicular development are associated with endothelin-1 (ET-1) gene expression in the porcine ovary. The localization of mature ET-1 peptide and of its mRNA was determined by immunohistochemistry and by in situ hybridization. Stage of follicular development associated with ET-1 expression was investigated in terms of follicular class and occurrence of atresia. The latter was investigated by determining the occurrence of DNA fragmentation in apoptotic cells on adjacent sections to those used for ET-1 gene expression. Fifteen ovaries from 10 prepubertal pigs stimulated with gonadotropin were collected; a total of 1050 follicles were examined. Specific ET-1 immunoreactivity was restricted to the ovarian vasculature and to the granulosa cell compartment of antral follicles. The pattern of ET-1 mRNA expression was similar to that found for ET-1 immunoreactivity. Primordial, primary, and most secondary follicles did not express ET-1. The theca cell layer did not express ET-1 regardless of follicle developmental stage. ET-1 expression occurred with a significantly greater probability (P < 0.001 by the likelihood ratio test) in the granulosa cell compartment of antral follicles than in any other follicle class. Furthermore, in antral follicles, ET-1 expression occurred with a greater likelihood in large antral follicles than in small antral follicles (P < 0.001 by the likelihood ratio test). In small antral follicles, only 16.8% expressed ET-1; in contrast, 66.7% of large antral follicles exhibited ET-1 expression. It is interesting that in follicles in which ovulation had already occurred, intense ET-1 expression was found only in the prominent developing vasculature, the other cells present in the luteinized follicle did not display any ET-1 expression. The pattern of ET-1 gene expression observed in this study would be in agreement with our previous suggestion of a plausible physiological role for ET-1 in preventing premature progesterone production by granulosa cells of an antral follicle. The occurrence of atresia and expression of ET-1 in the same follicle was rare. Small and large antral follicles constituted 5.1% and 5.6%, respectively, of the examined follicles in this category. The majority of atretic follicles did not express ET-1 and, conversely, follicles that expressed ET-1 were not atretic. To the best of our knowledge, this is the first report in which large, nonatretic follicles are clearly identified as the population of follicles expressing ET-1. The results of this study delineate the follicular developmental stage and the compartment of when and where ET-1 may be physiologically meaningful.

Male reproductive condition is the limiting factor of efficiency in the male effect during seasonal anestrus in female goats

Two experiments were conducted to determine whether the failure of males to induce sexual activity in goats during seasonal anestrus is due to unresponsiveness of females to male stimulus or insufficient stimulation from males. In the first study, one group of males (sexually inactive, SI; n = 4) was kept under natural photoperiod while the other (sexually active, SA; n = 4) was subjected to 2.5 mo of long days (16L:8D) and received 2 s.c. implants of melatonin. Two mo later, 2 different flocks of anovulatory goats previously separated from bucks were exposed to either SI (n = 34) or SA (n = 40) bucks. Progesterone assays and estrous behavior were used to determine ovarian and behavioral responses of the females to teasing. Of the goats exposed to SI males, only 2 ovulated, and none showed estrous behavior during the 35 days of the study. In contrast, all females (40 of 40) in contact with SA males ovulated and showed at least one estrous behavior during the first 11 days following male introduction (P < 0.001). Overall, 38 of 40 females stimulated with SA bucks were diagnosed pregnant at Day 35, according to progesterone assay (versus 0 in SI-treated group: P < 0.001). To control for a possible difference of responsiveness between flocks, the experiment was repeated 1 yr later using a single flock of goats divided into 2 groups. Again, over the first 14 days, 1 of 33 goats showed estrous behavior in the SI-treated group versus 27 of 33 in the SA-treated group (P < 0.001). Therefore, treating bucks with long days and melatonin increased their teasing capacity to induce sexual activity in females during anestrus. These results indicate that the absence of response to teasing at this time of the year is not due to female unresponsiveness, but to insufficient stimulation from the male.

Advanced insular thyroid carcinoma in a fourteen-year-old girl: twenty-four years of follow-up

Insular thyroid carcinoma has become a separate entity among thyroid malignancies. It is regarded as intermediate in aggressiveness between well-differentiated and anaplastic thyroid carcinomas. Reports on the clinical course of children with insular thyroid carcinoma are rare. We report the case of a 14-year-old girl who was admitted to our thyroid outpatient ward in 1975 with a scintigraphic cold thyroid nodule and multiple enlarged cervical lymph nodes. Chest radiography showed metastases in both lungs. After total thyroidectomy and, central and modified unilateral radical neck dissection, the girl was given a dose of 80 mCi 131I. Posttherapeutic scan demonstrated diffuse tracer uptake in both lungs. A second dose of 200 mCi 131I was administered 4 months later and another dose of 150 mCi 131I in July 1976. Subsequently, whole-body scans showed inconspicuous tracer distribution and chest x-rays were normal. The patient was treated with levothyroxine and followed until 1982, when she left Vienna. In 1999, the patient was contacted for reexamination. She has been well and had had two healthy children. The patient was taking 150 microg levothyroxine daily; she had a normal TSH value and her thyroglubulin was 0.3 ng/mL. Chest radiography and sonography of the neck showed no pathological findings. The paraffin sections of the patient's tumor were reexamined in 1999 and demonstrated the histologic characteristics of a poorly differentiated insular thyroid carcinoma (pT4a, pN1a, M1). These findings demonstrate that even in advanced stages, insular thyroid carcinoma treatment can be successful.

Radiation synovectomy using 165Dy ferric-hydroxide and oxidative DNA damage in patients with different types of arthritis

Radiation synovectomy is an effective treatment for chronic synovitis refractory to pharmacological treatment in patients with rheumatoid or seronegative arthritis. Concerns persist about possible radiation-induced cytogenetic damage after radiation synovectomy leading to recommendations to use this technique only in the elderly. Micronucleus (MN) frequency in lymphocytes and urinary excretion of 8-hydroxy-2'-deoxyguanosine (8OHdG) as an indicator of cellular oxidative DNA base damage are biomarkers of radiation-induced cytogenetic damage. The course of both biomarkers was studied in patients with different types of chronic synovitis undergoing radiation synovectomy with very short-lived 165Dy-ferric-hydroxide (DFH).

METHODS

Radiation synovectomy of the knee was performed in 13 men and 12 women (mean age, 44+/-15 y) using a mean activity of 9.48+/-1.65 GBq 165Dy-DFH in 27 consecutive treatments. MN frequency in lymphocytes and urinary excretion of 8OHdG, measured by high-performance liquid chromatography, were assessed before and 4 (MN only) and 20 h after radiation synovectomy.

RESULTS

Urinary excretion of 8OHdG in patients (in micromol/mol creatinine; pretreatment mean, 3.1+/-3.4; median, 2.27) was not significantly different from that in healthy volunteers (mean, 2.0+/-1.2; median, 1.87) and not altered by radiation synovectomy (post-treatment mean, 2.5+/-1.5; median, 2.04, NS). An increase in 8OHdG levels after radiation synovectomy of more than 1 SD was found in only 1 patient, who experienced leakage to the lymph nodes but who already had elevated urinary 8OHdG levels before treatment. The frequency of MN/500 binucleated cells (BNCs) was slightly lower in patients (pretreatment mean, 4.3+/-2.6; median, 4.25) than in healthy volunteers (mean, 5.4+/-2.3; median, 5.3) and did not significantly change after therapy, either (4-h post-treatment mean, 3.9+/-2.1, median, 3.8; 20-h post-treatment mean, 4.1+/-2, median 3.8 MN/500 BNC). In 22 of 27 treatments, no leakage to nontarget organs could be monitored, whereas leakage to the local lymph nodes and the liver was detected after 5 treatments.

CONCLUSION

Radiation synovectomy using 165Dy-DFH causes no significant radiation burden to most patients as indicated by the absence of adverse changes in levels of biomarkers of cytogenetic damage and a low incidence of leakage. These data suggest that the risk of malignancy may not be elevated.

Lumbar disc herniation in a 27-month-old child. Case report

The occurrence of disc herniation is rare in children. A 27-month-old child fell from his cradle and developed, in the following 2 weeks, irritability, low-back pain, and difficulty in walking. On physical examination a compensatory gait, paravertebral muscle spasm, and a restricted right straight-leg raising test were demonstrated. Plain x-ray films revealed a narrowed L4-5 intervertebral space. Magnetic resonance imaging of the lumbosacral spine demonstrated decreased signal in the L4-5 disc, with posterior disc protrusion. At surgery, blood infiltrating the subperiosteal plane was observed. Via a left hemilaminectomy and under microscopic magnification, the left L-5 nerve root was found to be intact, and on the right side significant nerve root compression was identified. During dissection an accidental dural tear occurred. A right L-4 hemilaminectomy was performed, and the disc fragments were removed until a complete nerve root decompression was obtained and the dura was repaired. The child recovered uneventfully and was asymptomatic 7 years postsurgery. This child is one of the youngest patients with a herniated disc reported in the world literature. The authors discuss the diagnostic difficulties and management of this entity in children.

Mechanisms underlying endothelin's inhibition of FSH-stimulated progesterone production by ovarian granulosa cells

In previous studies in porcine granulosa cell cultures, endothelin-1 (ET-1) was shown to inhibit FSH-stimulated cAMP and progesterone accumulation, and to increase inositol phosphate formation and cytosolic calcium ion concentration. The latter results suggest an action of ET-1 via the activation of phospholipase C. Here we have investigated the following experimental questions. (1) Does ET-1 activate PKC in ovarian cells? (2) Does the cellular mechanism(s) whereby ET-1 interferes with the steroidogenic action of FSH in granulosa cells involve an impairment of cAMP generation or action? And (3) how does the site(s) of the inhibitory effect(s) of ET-1 and TPA on FSH-stimulated progesterone accumulation in cultured granulosa cells compare? In the present investigation, ET-1 (1 microM) induced rapid cytosol-to-membrane translocation of [3H]phorbol 12,13-dibutyrate binding sites, indicating protein kinase C (PKC) activation. At 24 or 48 h, ET-1 inhibited FSH-, but not forskolin (1 microM)-induced, cAMP accumulation. Cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) messenger RNA (mRNA) accumulation was stimulated by FSH, 8-bromo-cAMP (8Br-cAMP, 0.5 mM) and forskolin. ET-1 significantly inhibited this effect of FSH, but not the effects of 8Br-cAMP and forskolin. Progesterone production decreased commensurately with this inhibitory action of ET-1 on the FSH-stimulated accumulation P450scc mRNA. The PKC activator, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), suppressed steroidogenesis stimulated by forskolin and 8Br-cAMP as well as FSH. In conclusion, ET-1 inhibited FSH-stimulated cAMP accumulation, P450scc expression, and progesterone production in porcine granulosa cell cultures. The data are compatible with pre-adenylate cyclase site of action. Although ET-1 activated PKC, TPA, unlike ET-1, seems to inhibit steroidogenesis by interfering with cAMP action.

Anaplastic (undifferentiated) thyroid carcinoma (ATC). A retrospective analysis

BACKGROUND

Old age, reduced general condition and far advanced tumor stage associated with poor prognosis induced the belief that, apart from verifying the diagnosis of anaplastic thyroid carcinoma (ATC) by biopsy, no additional surgery would be justified. However, in some cases, an ultraradical approach was recommended in order to improve the quality of life and survival.

METHODS

These are the results of a retrospective analysis involving 120 patients subjected to restricted radical surgery (excising as much as possible of the tumor and local metastases, foregoing ultraradical removal of vital organs such as esophagus, larynx and trachea).

RESULTS

Irrespective of the surgical approach used, 6+/-2% of the patients were alive after 5 years (median survival time: 3.1 months). Patients without tumor residues (R0-resections; extending to soft tissue only; Kaplan-Meier estimate - cumulative survival 15+/-5%) had a significantly better prognosis than patients with tumor residues (R1/R2-resections; no patient survived 5 years; P<0.001). Tumor morphology (spindle cells, giant cells, mixed cells) or differentiated parts of the tumor as well as lymph-node involvement had no statistically significant impact on the prognosis.

CONCLUSIONS

In ATC, the objective should be to remove as much of the carcinoma as possible (in the ideal case, a thyroidectomy); if lymph nodes are affected, neck dissection should be the goal, if possible (restricted radical approach, improving quality of life). Ultraradical surgery to include segmental resection of larynx, trachea or esophagus do not seem to be indicated, as prolonged survival is questionable and quality of life is certainly diminished.

Impact of breast feeding on admission for pneumonia during postneonatal period in Brazil: nested case-control study

OBJECTIVE

To determine whether breast feeding protects infants against pneumonia and whether the protection varies with age.

DESIGN

Nested case-control study.

SETTING

Pelotas, southern Brazil.

SUBJECTS

Cases were 152 infants aged 28-364 days who had been admitted to hospital for pneumonia. Controls were 2391 cases in a population based case-control study.

MAIN OUTCOME MEASURE

Odds ratio of admission for pneumonia according to type of milk consumed (breast milk alone, breast and formula milk, or formula milk and other fluids only), use of fluid supplements apart from formula milk, and use of solid supplements.

RESULTS

Infants who were not being breast fed were 17 times more likely than those being breast fed without formula milk to be admitted to hospital for pneumonia (95% confidence interval 7.7 to 36.0). This relative risk was 61 (19.0 to 195.5) for children under 3 months old, decreasing to 10 (2.8 to 36. 2) thereafter. Supplementation with solids was associated with a relative risk of 13.4 (7.6 to 23.5) for all infants and 175 (21.8 to 1405.1) for those under 3 months old.

CONCLUSION

Breast feeding protects young children against pneumonia, especially in the first months of life. These results may be used for targeting intervention campaigns at the most vulnerable age groups.

[The value of fine-needle aspiration biopsy (FNAB) in the differential diagnosis of the "cold" thyroid nodule]

INTRODUCTION

According to the literature, fine needle aspiration biopsy (FNAB) should be the first line test to assess thyroid nodules. The value of fine needle aspiration biopsy in the differential diagnosis of "cold" thyroid nodules is discussed.

METHODS

105 consecutive patients undergoing surgery for solitary cold nodule or a dominant cold nodule in multinodular goiter and having a preoperative fine needle aspiration biopsy, are analysed.

RESULTS

The cytologic results were benign in 48 cases, malignant in 8 cases and indeterminate (follicular neoplasia) in 29. Twenty biopsies were inadequate. Excluding inadequate and indeterminate biopsy results and calculating microcarcinomas (as incidental findings) as "true negative", sensitivity was 56%, specify 94% and accuracy 88%. There was a negative predictive value of 92% and a positive predictive value of 63%.

CONCLUSIONS

Fine needle aspiration biopsy is helpful as an additional test. The indication for surgery for a "cold" thyroid nodule must be established in conjunction with clinical findings and other investigation procedures.

Luteinizing hormone (LH) stimulates both intracellular calcium ion ([Ca2+]i) mobilization and transmembrane cation influx in single ovarian (granulosa) cells: recruitment as a cellular mechanism of LH-[Ca2+]i dose response

The gonadotropic hormones, LH and FSH, activate adenylyl cyclase in their respective target cells and thereby initiate many biochemical responses. In addition to stimulating cAMP production, both LH and FSH promote agonist-specific increases in the cytoplasmic concentration of free calcium ions ([Ca2+]i) in gonadal cells. Here, we have applied single cell fluorescence video microscopy with the Ca2+-sensitive dye fura-2 to investigate the mechanism(s) by which LH induces a rise in the [Ca2+]i in individual (swine) granulosa cells collected from single Graafian follicles. Stimulation with LH induced a rapid onset, biphasic, spike- and plateau-like [Ca2+]i signal in responsive granulosa cells. The cellular mechanisms mediating this biphasic LH-stimulated increase in [Ca2+]i were examined by external Ca2+ removal and via the manganese (Mn2+) quench technique, which showed that LH triggers initial intracellular Ca2+ mobilization followed by delayed transmembrane Ca2+ influx. Single cell Ca2+ assessment of the LH dose-response mechanism(s) revealed that higher concentrations of LH progressively recruit a larger number of responding individual granulosa cells. Further analyses disclosed a marked [Ca2+]i response heterogeneity among individual granulosa cells harvested from the same Graafian follicle. In addition, the percentage of cells responding to LH [but not to an alternative putative agonist of the phospholipase C (PLC) pathway, viz. endothelin-1] with a biphasic [Ca2+]i rise increased with maturational development of the follicle. Pretreatment of granulosa cells with a specific PLC inhibitor, U-73122 (but not with its inactive congener U-73343), significantly reduced the percentage of cells responding to a LH challenge from 78% to 25% (P < 0.0001) and prolonged the time required to achieve a half-maximal value of the [Ca2+]i transient, viz. from 22 +/- 1.5 sec (n = 27 cells) to 39 +/- 7.2 sec (n = 12 cells; P = 0.002). In cell population studies, LH stimulated in a concentration- and time-dependent manner the accumulation of inositol phosphate in porcine granulosa cells. In summary, the present single cell investigations in mature granulosa cells demonstrate that LH drives initial intracellular Ca2+ mobilization followed by transmembrane divalent cation influx. The PLC inhibitor U-73122 antagonizes this action of LH. By analyzing [Ca2+]i responses in individual living granulosa cells, we further show that, despite within-follicle diversity, the LH dose biphasic [Ca2+]i response arises via the recruitment of a larger number of responding gonadal cells rather than by increased [Ca2+]i signal amplitude. Finally, the percentage of individual LH (but not endothelin-1)-responding granulosa cells increases with follicular maturation. Collectively, these data highlight the potential importance of the LH-stimulatable, PLC-transduced [Ca2+]i signaling mechanism in the later stages of granulosa cell differentiation.

Length of postpartum anestrus in goats in subtropical Mexico: effect of season of parturition and duration of nursing

The aim of this study was to determine whether season of birth and length of nursing affected the duration of postpartum anestrus in Creole female goats maintained on a constant plane of nutrition in subtropical Mexico. Three experiments were conducted in the Laguna region in the State of Coahuila, Mexico (26 degrees N). In the first experiment, 34 goats gave birth in January; in the second, 31 females gave birth in May; and in the third, 22 goats kidded in October. At parturition, females were allocated to 1 of 3 groups based on body weight and date of parturition: kids were weaned at 2, 30 or 90 d according to their group. After weaning, females were milked manually once a day until the end of the study. All animals were kept in a shed and were fed alfalfa ad libitum and given 200 g of concentrate daily. Starting 1 wk after parturition, estrous behavior was detected twice daily using an apron-bearing male, and blood samples were obtained twice weekly to determine ovarian activity from the plasma progesterone levels. A strong effect of month of parturition was found on the duration of postpartum anestrus (P < 0.0001), which was longer in females kidding in January (about 200 d) than in those kidding in May (about 100 d) or October (about 50 d). A tendency for an interaction between season of parturition and length of nursing was observed in the length of anovulation (P < 0.07): for parturition in October, anestrus was longer when kids were weaned after 90 d than after 2 or 30 d (P < 0.01). Season of parturition also affected dates of reinitiation of ovulatory and estrous activity (P < 0.001). Proportions of normal, short and long cycles and of associations between estrous and ovulations were not influenced by season of parturition or the age of weaning. These data demonstrate that in subtropical latitudes, season of parturition can dramatically influence the duration of postpartum anestrus independently of the availability of food.

Clinical application of ketamine ointment in the treatment of sympathetically maintained pain

The objective of this study was to determine the clinical efficacy of topical ketamine in relieving sympathectically maintained pain, including complex regional pain syndrome types I and II, involving the upper and/or lower extremities. In an open clinical pilot study of five referral patients diagnosed with sympathetically maintained pain who were unresponsive to conventional modalities, a single dose of topical ketamine was administered. Age, gender, duration or degree of disease and concurrent medication were not controlled. Ketamine was prepared for transdermal delivery in pluronic lethicin organogel (PLO) in calibrated applicators. Concentrations ranged from 10 to `50 mg/mL. Dosage ranged from 10 mg to 700 mg per single application. Each dosage was deternined clinically based on location and suface area of involvement. Pain intensity was measured using a validated mumeric analogue scale (NAS). Ketamine in PLO applied to the uper and/or lower extremities with sympathetically maintained pain resulted in significant pain reduction relative to pretreatment NAS of 65% to 100% . Initial response was within 20 seconds to three minutes, with NAS rating 15 minutes postapplication. No reported side effect occurred on patient follow-up at 24 and 48 hours. Single-dose, topical application of ketamine in PLO (patent pending) appears clinically effective in relieving sympathetically maintained pain of the extremities without apparent side effects. Further controlled studies are warranted to define patient selection, optimize dosage and validate the prominent analgesic effects obtained in this heretofore difficult-to-treat pain syndrome. This was an independent study in joint cooperation with representatives from the Univesity of California at Irvine, Loma Linda University Medical Center and private practice.

Geological record and reconstruction of the late Pliocene impact of the Eltanin asteroid in the Southern Ocean

In 1995, an expedition on board the research vessel FS Polarstern explored the impact site of the Eltanin asteroid in the Southern Ocean, the only known asteroid impact into a deep ocean basin. Analyses of the geological record of the impact region place the event in the late Pliocene (approximately 2.15 Myr) and constrain the size of the asteroid to be >1 km. The explosive force inferred for this event places it at the threshold of impacts believed to have global consequences, and its study should therefore provide a baseline for the reconstruction and modelling of similar events, which are common on geological timescales.

The effect of using different levels of shrimp meal in broiler diets

The objective of this study was to measure the effect of substituting different levels of shrimp meal (SM) for soybean meal (SBM) in broiler diets. In Experiment 1, 0, 10, 20, 30, and 40% of the crude protein contributed by the SBM in broiler diets was substituted by crude protein from SM. In Experiment 2, 0, 60, 80, and 100% of the crude protein contributed by SBM in broiler diets was replaced by crude protein from SM. Body weight, cumulative feed consumption, and feed conversion (feed:gain) were determined on a weekly basis for 49 d in Experiment 1 and 42 d in Experiment 2. Mortality was reported daily. Carcass weight and percentage yield were determined on a prechilled basis. In Experiment 1, no significant differences were found for body weight, feed consumption, feed conversion, mortality, carcass weight, or yield. In the second experiment, body weight was found to be significantly higher (P < 0.01) at 21, 28, 35, and 42 d of age in treatments in which SM was introduced at a 100% substitution for SBM. Growth responses to SM were also seen at lower levels of substitution at 21, 28, and 35 d. No significant differences were observed for feed consumption, feed conversion, mortality, or carcass yield for any of the treatments. Carcass weight increased significantly by 12.1% when SM was substituted 100% for SBM. Results of the present study show that the particular SM used in this study could partially or totally replace SBM in broiler diets without negatively affecting performance or carcass quality.

[Hospitalization due to pneumonia: the influence of socioeconomic and pregnancy factors in a cohort of children in Southern Brazil]

OBJECTIVE

To investigate the influence of socioeconomic and gestational factors on admission due to pneumonia in the post-neonatal period.

METHODOLOGY

Cohort. Children born in the city Pelotas, Brazil, in 1993. Cases were children admitted to hospital for 24 hours or more, between the ages of 28 and 364 days, with a diagnosis of pneumonia.

RESULTS

Of the 5,304 children in the cohort, 152 (2.9%) were hospitalized with pneumonia. The positive predictive value of the clinical diagnosis compared to the radiological assessment was 76%. Analysis by conditional logistic regression showed that social class and maternal schooling were strongly inversely associated with pneumonia Children of adolescent mothers were twice as likely to be admitted. The relative risk for children whose mothers were of parity three or greater was 2.8 relative to primiparae. Maternal weight gain during pregnancy of less than 10 kg was associated with a 40% increase in risk.

CONCLUSION

Socioeconomic factors were important determinants of pneumonia admissions. Maternal age, parity and weight gain were also significant risk factors.

Risk factors for childhood pneumonia among the urban poor in Fortaleza, Brazil: a case--control study

Reported are the results of a case-control study carried out between July 1989 and June 1990 in Fortaleza city, Ceará State, Brazil, to determine the factors that place young children living in urban slum conditions at increased risk of contracting pneumonia. Cases were 650 under-2-year-olds with a radiological diagnosis of pneumonia who were recruited at the main paediatric hospital in the city over a full calendar year. Age-matched controls were recruited from the neighbourhood where the cases lived. Cases and controls were compared with respect to a variety of sociodemographic, environmental, reproductive, nutritional, and morbidity factors, and a risk factor questionnaire was administered to the mother of each child or to the child's normal guardian. Cases and controls were also weighed and measured. Malnutrition was the most important risk factor for childhood pneumonia in the study population, with weight-for-age, height-for-age, and weight-for-height also being important risk factors. In view of the high prevalence of stunting in the study population, there is an urgent need to reduce the level of malnutrition as a priority. Attendance at a day care centre was also associated with a high odds ratio. In view of the growing numbers of children attending day care centres in both developing and developed countries, it is essential that ways be identified to improve the design and management of such centres in order to minimize the risk of pneumonia. Increased risks of childhood pneumonia were also associated with low birth weight, non-breast-feeding, crowding, high parity, and incomplete vaccination status, but not with socioeconomic status or environmental variables. Finally, children who had suffered from previous episodes of wheezing or been hospitalized for pneumonia had a greater than threefold increased risk of contracting the disease.

Nature of endothelin binding in the porcine ovary

We investigated the nature of endothelin (ET) binding in the porcine ovary. We demonstrated the presence of high affinity (Kd = 0.72; 95% confidence interval = 0.43-1.1 nM) binding sites for ET-1 in the porcine ovary. The binding capacity for this ET-1-specific binding site was 97 pmol/micrograms DNA (95% confidence interval = 90-107). Autoradiographic studies showed that putative ET receptors reside in the granulosa cell layer of the maturing Graafian follicle and in the vascular components of the corpora lutea. The relative abundance of ET receptors was greatest in granulosa cells of large antral follicles, whereas ET binding was absent in granulosa cells of preantral follicles and in luteal cells. ET binding by cultured granulosa cells was further characterized by RRA and shown to exhibit a rank order of binding affinities for different ET isopeptides. The observed rank order indicates that the ET receptors present on granulosa cells are of the ET(A) receptor subtype. The radioreceptor studies also indicated that granulosa cells collected from large antral follicles (9-10 mm in diameter) have a greater binding capacity for [125I]ET-1 in culture than granulosa cells collected from smaller follicles. When cultured granulosa cells were exposed to 100 nM ET-1 or 14 nM 12-O-tetradecanoylphorbol 13-acetate overnight, the percentage of specific [125I]ET-1 binding was reduced (12% and 50%, respectively), indicating a down-regulation of the ET receptor by these treatments. In summary, we have characterized the distribution, isopeptide specificity, relative abundance, and down-regulation of putative ovarian endothelin receptors of subtype ET(A) on swine granulosa cells. Such results in conjunction with other available literature strongly suggest that granulosa cells of maturing Graafian follicles are targeted by ET-1. An additional physiological role for ET-1 in the ovary is suggested by the presence of putative ET receptors in the vasculature of the corpus luteum.

Dynamics of propagating waves in the olfactory network of a terrestrial mollusk: an electrical and optical study

1. The procerebral (PC) lobe of the terrestrial mollusk Limax maximus contains a highly interconnected network of local olfactory interneurons that receives ipsilateral axonal projections from superior and inferior noses. This network exhibits an approximately 0.7-Hz intrinsic oscillation in its local field potential (LFP). 2. Intracellular recordings show that the lobe contains at least two classes of neurons with activity phase locked to the oscillation. Neurons in one class produce periodic bursts of spikes, followed by a period of hyperpolarization and subsequently a depolarizing afterpotential. There is a small but significant chance for a second burst to occur during the depolarizing afterpotential; this leads to a double event in the LFP. Bursting neurons constitute approximately 10% of the neurons in the lobe. 3. Neurons in the other class fire infrequently and do not produce periodic bursts of action potentials. However, they receive strong, periodic inhibitory input during every event in the LFP. These nonbursting cells constitute the major fraction of neurons in the lobe. There is a clear correlation between the periodic burst of action potentials in the bursting neurons and the hyperpolarization seen in nonbursting neurons. 4. Optical techniques are used to image the spatially averaged transmembrane potentials in preparations stained with voltage-sensitive dyes. The results of simultaneous optical and electrical measurements show that the major part of the optical signal can be interpreted as a superposition of the intracellular signals arising from the bursting and nonbursting neurons. 5. Successive images of the entire PC lobe show waves of electrical activity that span the width of the lobe and travel its full length along a longitudinal axis. The direction of propagation in the unperturbed lobe is always from the distal to the proximal end. The wavelength varies between preparations but is on the order of the length of the preparation. 6. One-dimensional images along the longitudinal axis of the lobe are used to construct a space-time map of the optical activity, from which we calculate the absolute contribution of bursting and nonbursting neurons to the optical signal. The contribution of the intracellular signals from the two cell types appears to vary systematically across the lobe; bursting cells dominate at middle and proximal locations, and nonbursting cells dominate at distal locations. 7. The direction and form of the waves can be perturbed either by microsurgical manipulation of the preparation or by chemical modulation of its synaptic and neuronal properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Mechanisms by which endothelin-1 stimulates increased cytosolic free calcium ion concentrations in single rat Sertoli cells

The regulation by endothelin-1 (ET-1) of cytosolic free calcium ion concentrations ([Ca2+]i) was investigated in single immature rat (testicular) Sertoli cells. [Ca2+]i was estimated in individual gonadal cells by digital imaging videomicroscopy using the calcium indicator dye fura-2/AM. Two concentration-dependent types of ET-1-induced [Ca2+]i signals were observed. Responses to high ET-1 concentrations (1.0-1000 nM) were characterized by a biphasic, rapid, and transient [Ca2+]i rise (spike) within 10 sec, followed by an exponential decrease toward a new steady state level (plateau phase) in 98% of responsive cells. At low concentrations of ET-1 (0.001 or 0.1 nM), the [Ca2+]i increase was slower, reaching peak values 40-100 sec after stimulation and remaining elevated for 2-3 min of observation. There was cell-cell heterogeneity in the amplitude and kinetics of the [Ca2+]i response to the same concentration of ET-1. However, there was a significant ET-1 concentration-dependent increase in the total percentage of cells responding to ET-1. Removal of extracellular Ca2+ or use of Ca2+ channel blockers (verapamil or cobalt) did not affect the ET-1-induced [Ca2+]i spike phase, but abolished the plateau phase, suggesting that ET-1 induces the mobilization of Ca2+ from internal stores, followed by calcium influx from extracellular sources. In cell population experiments, ET-1 attenuated FSH-stimulated cAMP and estradiol accumulation by Sertoli cells. These inhibitory effects were mimicked by phorbol 12-myristate 13-acetate, an activator of protein kinase-C, suggesting that ET-1 action on Sertoli cells might be linked to the protein kinase-C pathway. In conclusion, the present investigations demonstrate that ET-1 activates an intracellular signaling pathway involving [Ca2+]i in single rat Sertoli cells. The sources of the biphasic [Ca2+]i response include mobilization of Ca2+ from internal stores, followed by Ca2+ influx via verapamil- and cobalt-sensitive Ca2+ channels. Increasing ET-1 concentrations recruit an increasing number of individual Sertoli cells responding with a spike-plateau [Ca2+]i signal, thus offering a mechanism at the single cell level for the ET dose-response curve.

Risk factors for pneumonia among children in a Brazilian metropolitan area

OBJECTIVE

To investigate risk factors for pneumonia for infants < 2 years of age.

DESIGN

Hospital-based, case-control study with neighborhood control subjects.

SETTING

Urban area in southern Brazil.

SUBJECTS

Five hundred ten infants with radiologically confirmed pneumonia who were admitted to a pediatric hospital. One age-matched neighborhood control subject was selected for each case.

RESULTS

Multiple conditional regression modeling was used to control for confounding, taking into account the hierarchical relationships between risk factors. The incidence of radiologically confirmed pneumonia was associated with low paternal education, the number of persons in the household, young maternal age, attendance at day-care centers, low birth weight and weight-for-age, lack of breast-feeding and of non-milk supplements, and a history of previous pneumonia or wheezing. Day-care center attendance showed the highest risk, with an adjusted odds ratio of 11.75.

CONCLUSIONS

In addition to continued efforts toward appropriate case management, actions directed against the above risk factors may help prevent the major cause of deaths of children younger than 5 years.

Cellular basis for follicle-stimulating hormone-stimulated calcium signaling in single rat Sertoli cells: possible dissociation from effects of adenosine 3',5'-monophosphate

To study the cellular basis for FSH-stimulated dose-dependent graded increases in intracellular Ca2+ concentrations in populations of Sertoli cells, we investigated the effects of FSH on free Ca2+ ion concentrations ([Ca2+]i) in individual rat Sertoli cells using the Ca(2+)-sensitive dye fura-2/AM and digital fluorescent videomicroscopy. Ovine or rat FSH elicited a hormone-specific rise in [Ca2+]i within 20-140 sec, with a peak level 2.7 +/- 0.9-fold greater than the basal value (mean +/- SEM; n = 8) lasting for 4-16 min. The amplitude and kinetics of the FSH-induced [Ca2+]i signal were not dose dependent. Instead, increasing doses of FSH recruited a higher percentage of responding cells. Chelation of extracellular Ca2+ or cotreatment with verapamil or cobalt abolished FSH-induced [Ca2+]i increases. Furthermore, in the presence of extracellular Mn2+, direct evidence for FSH-mediated Ca2+ influx was obtained from the quench of fura-2 fluorescence. Induced Ca2+ increases were mimicked by forskolin or protein kinase-A type I activators [8-(6-amino-hexyl)amino-cAMP and N6-benzoyl-cAMP (N6B)]. However, the cAMP analogs, 8-bromo-cAMP, N6,2'-O-dibutyryl cAMP, or protein kinase-A type II activators (8-thiomethyl-cAMP and N6B), induced [Ca2+]i increases even in the absence of extracellular Ca2+, and the time course of the [Ca2+]i rise induced by cAMP analogs was more rapid than that induced by FSH. Similarly, the uninhibited rise in [Ca2+]i induced by FSH in pertussis toxin-pretreated Sertoli cells suggests that PT-sensitive G-proteins are not involved in the action of FSH on [Ca2+]i. In summary, we demonstrate that FSH evokes sustained [Ca2+]i increases in single Sertoli cells in a nongraded fashion and recruits increasing numbers of responding cells in a dose-dependent fashion. We also provide explicit evidence that FSH induces Ca2+ influx. Mimicry of the FSH-induced [Ca2+]i rise by certain cAMP analogs [8-(6-amino-hexyl)amino-cAMP and N6B; protein kinase-A type I activator] or forskolin suggests that Ca2+ may be part of a dual pathway of cAMP-initiated intracellular signaling.

Waves and stimulus-modulated dynamics in an oscillating olfactory network

The temporal dynamics of electrical activity in an olfactory organ, the procerebral lobe of the terrestrial mollusc Limax maximus, is studied. The lobe exhibits intrinsic oscillations in its field potential. Intracellular recordings show that the lobe contains two classes of neurons, both with activity phase-locked to the oscillation. Neurons in one class produce periodic bursts of spikes while those in the other class fire infrequently but receive strong, periodic inhibition whose onset coincides with the burst. The large-scale activity of these neurons is imaged in preparations stained with voltage-sensitive dyes. We observe waves of electrical activity that span the width of the lobe and travel its full length along a longitudinal axis. Simultaneous optical and intracellular recordings show that the form of the wave reflects the electrical activity of both classes of neurons. The application of natural odor stimuli causes the electrical activity along the lobe to transiently switch from the state with propagating waves to one with spatially uniform oscillations. The behavioral and computational relevance of this change in global timing is discussed.

Determinants of forage quality in Pensacola bahiagrass and Mott elephantgrass

Our objective was to determine animal responses and forage characteristics that could explain the greater forage quality of 'Mott' dwarf elephantgrass (Pennisetum purpureum Schum.) than that of 'Pensacola' bahiagrass (Paspalum notatum Flugge). Both grasses were harvested after 5 wk of regrowth in June and September. Sheep fed Mott hays had greater (P = .001) voluntary intake of digestible OM (DOM) than did those fed Pensacola, but voluntary intake of ash-free NDF (NDFa) did not differ (P = .21) between grasses. When hays were fed at equal NDFa intakes, sheep fed Mott chewed at a greater (P = .002) rate during eating, spent less (P = .028) time ruminating per unit OM intake, and had smaller (P = .006) prefeeding digesta pools of total and indigestible NDFa. Mott hays had greater N and K and smaller NDFa concentrations. Mott had greater (P = .001) epidermis and smaller (P = .001) sclerenchyma proportions in leaf blades, and leaf epidermis of Mott was more digestible (P = .011) in vitro. For both grasses, hays harvested in June had greater (P = .011) voluntary intake of DOM and shorter (P = .082) mean retention time of small ruminal digesta particles (< 1.18 mm) than did those harvested in September. Within grasses, there were no seasonal differences in NDFa concentration in hay, or in leaf anatomy. A less fibrous leaf structure and a more readily digested leaf epidermis may have accounted for the greater DOM intake of Mott than of Pensacola, but the greater DOM intake of hays harvested in June than of those harvested in September was not explained by measured forage characteristics.

Sites of inhibition of steroidogenesis by activation of protein kinase-C in swine ovarian (granulosa) cells

We tested the hypothesis that low density lipoprotein (LDL) metabolism and cellular concentrations of gene transcripts of cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc mRNA) are sites of significant protein kinase-C (PKC) action in the long term (48-h) inhibitory modulation of steroid hormone biosynthesis in ovarian granulosa cells. To this end, we used 12-O-tetradecanoylphorbol-13-acetate (TPA) as an activator of PKC and a monolayer culture system of immature swine granulosa cells responsive to insulin and lipoprotein under serum-free conditions. Insulin-regulated LDL metabolism was identified as a major site of TPA-mediated inhibition of steroidogenesis in granulosa cells. Treatment with TPA (30 ng/ml), but not inactive phorbol base, effectively decreased insulin-stimulated [125I]iodo-LDL binding by 75%, internalization by 90%, and degradation by 75%, as well as delivery and utilization of the [3H]cholesterol moiety of LDL in progesterone biosynthesis by intact granulosa cells. Cellular concentrations of P450scc mRNA, as measured by Northern blot hybridization with a 32P-labeled 1-kilobase porcine cDNA clone, were significantly increased by insulin. This insulin effect was virtually abolished by cotreatment with TPA (30 ng/ml). In contrast, accumulation of mRNA transcripts of a non-steroidogenic gene, 3-phosphoglyceraldehyde dehydrogenase, but not 18S ribosomal RNA, was enhanced by TPA. In summary, major inhibitory actions of PKC activation on granulosa cell steroidogenesis are expressed at specific loci of LDL metabolism, including LDL receptor number, internalization, and degradation, as well as the delivery and utilization of the [3H]cholesterol moiety of LDL to intact granulosa cells. Moreover, a PKC activator suppresses the intracellular accumulation of insulin-stimulated P450scc mRNA, but not that of phosphoglyceraldehyde dehydrogenase or 18S ribosomal RNA. The results obtained in this in vitro study suggest that the inhibition by TPA at these different sites along the steroidogenic pathway may be similar to that which occurs via hormones that work through the PKC system, such as prostaglandin F2 alpha.

Actions of endothelin-1 on swine ovarian (granulosa) cells

We have investigated the regulatory actions of endothelin-1 (ET-1) on inositol phosphate accumulation, cytosolic free Ca2+ ion concentrations ([Ca2+]i), and basal and FSH-stimulated progesterone and cAMP accumulation by swine granulosa cells in serum-free cultures. ET-1 induced a rapid stimulation of phosphoinositide hydrolysis in populations of granulosa cells, as inferred by the rapid appearance of soluble inositol polyphosphates in response to ET-1 exposure. At the single cell level, fura-2 videomicroscopy was used to measure [Ca2+]i in individual granulosa cells. We observed cell-cell variability in the threshold concentration of ET-1 required to induce a rise in [Ca2+]i. More than 75% of granulosa cells responded to maximal doses of ET-1. The following parameters of [Ca2+]i were influenced by ET-1 concentration: percentage of responding cells, lag time for the onset of response, amplitude, and kinetics of the response. Two types of ET-1-mediated [Ca2+]i rises were observed. One type exhibited rapid Ca2+ kinetics, reaching at least a 2-fold increase above basal (spike phase) within 1-10 sec and returning to a new steady state (plateau phase) 2 min after onset. The other mode of response had slower [Ca2+]i kinetics, in which 50 sec or more were required to double [Ca2+]i, which remained at this level throughout the observation period (2.5 min). These responses to ET-1 were specific and were not initiated by vasopressin or tumor necrosis factor-alpha. In cell population studies using monolayer cultures of swine granulosa cells, ET-1 inhibited FSH-stimulated accumulation of progesterone and cAMP. The ET-1-mediated inhibition of FSH-stimulated accumulation of progesterone required at least 4 h of ET-1 exposure. The ET-1-mediated inhibition of both the FSH-stimulated accumulation of progesterone and cAMP after 24-h incubation was mimicked by an activator of protein kinase-C, phorbol 12-myristate 13-acetate, but not by an inactive phorbol. These observations in either single cells or populations of swine ovarian (granulosa) cells are consistent with a possible regulatory role of an ET-1-activated intracellular signaling pathway involving inositol phosphates, [Ca2+]i, and protein kinase-C in the mammalian granulosa cell.