Videothoracoscopy an effective method for evaluating and managing thoracic trauma patients

BACKGROUND

The objective of this study was to assess the diagnostic and therapeutic effectiveness of videothoracoscopy in thoracic trauma patients.

METHODS

The design was a retrospective review. The setting was a major trauma center at an urban county hospital. Forty-one hemodynamically stable patients sustaining thoracic trauma were reviewed (34 penetrating and 7 blunt injuries). In the acute setting (< 24 h), videothoracoscopy was used for continued bleeding(6) and suspected diaphragmatic injury(17). Thoracoscopy was used in delayed settings (> 24 h) for treatment of thoracic trauma complications(18) including clotted hemothorax(14), persistent air leak(1), widened mediastinum(1), and suspected diaphragmatic injury(2).

RESULTS

The average Injury Severity Score (ISS) of these patients was 18.9 +/- 10.0. Three of 6 patients (50%) with continued bleeding were successfully treated thoracoscopically. Nine of 10 (90%) diaphragmatic injuries were confirmed by thoracoscopy, and 7 of these 9 patients (77%) were repaired thoracoscopically. Thirteen of 14 patients (93%) with clotted hemothoraces and one with a persistent air leak were treated successfully using thoracoscopy. An aortic injury was ruled out in one patient.

CONCLUSIONS

Videothoracoscopy is a safe, accurate, minimally invasive, and potentially cost-effective method for the diagnosis and therapeutic management of thoracic trauma patients.

Structure-function relationship of human parathyroid hormone in the regulation of vitamin D receptor expression in osteoblast-like cells (ROS 17/2.8)

Studies of the relationship between PTH structure and function in the activation of protein kinases have revealed that different regions within the biologically active PTH-(1-34) peptide are responsible for different functions. The first two N-terminal amino acids are required for plasma membrane adenylyl cyclase stimulation, and the C-terminal region 29-32 is necessary for the translocating activity of protein kinase C. In the present study, we explored the structure-function relationship of human (h) PTH in the regulation of the vitamin D receptor (VDR) in osteoblast-like cells (ROS 17/2.8). VDR-rich cytosol extract was prepared after the confluent cells were incubated with different hPTH fragments for 16 h. hPTH-(1-34) at concentrations of 10(-9)-10(-7) M caused a dose-dependent decrease in VDR content from a control level of 70.2 +/- 2.2 fmol/mg protein to 62.1 +/- 3.3 (-16%) at 10(-9) M, 52.3 +/- 5.3 (-25.5%; P < 0.02) at 10(-8) M, and 45.5 +/- 3.5 fmol/mg protein (-35.3%; P = 0.001) at 10(-7) M (n = 6). hPTH-(1-31) also decreased VDR content from 65.5 +/- 3.6 to 55.2 +/- 7.9 (-19.5%) at 10(-9) M, 44.3 +/- 5.8 (-32.4%; P < 0.05) at 10(-8) M, and 40.6 +/- 3.2 fmol/mg protein (-38.9%; P < 0.05) at 10(-7) M (n = 6). Incubation of ROS 17/2.8 cells with 0.5 nM 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] led to up-regulation of VDR content by 340-370% of the control value. hPTH-(1-34) decreased the VDR up-regulatory effect of 1,25-(OH)2D3 from 340% to 230% of the control value at 10(-8) M (P < 0.0001) and 170% of the control value (P < 0.0001) at 10(-7) M, respectively (n = 6). hPTH-(1-31) also decreased the receptor up-regulatory effect of 1,25-(OH)2D3 from 370% to 286% (P < 0.02) at 10(-8) M and 220% (P < 0.002) at 10(-7) M, respectively (n = 6). hPTH-(3-34) and -(13-34) at concentrations of 10(-9)-10(-7) M did not decrease VDR content in either the absence or presence of 1,25-(OH)2D3. Quantitation of VDR messenger RNA by reverse transcription-polymerase chain reaction showed that PTH-(1-34) and -(1-31) at 10(-7) M, but not PTH-(3-34) and -(13-34), inhibited ROS 17/2.8 cell VDR gene expression in both the absence and presence of 1,25-(OH)2D3.(ABSTRACT TRUNCATED AT 400 WORDS)

Treatment of Trichuris trichiura infections improves growth, spelling scores and school attendance in some children

The effects of treating Trichuris trichiura infections were investigated in 407 Jamaican children age 6 to 12 y. The children were randomly assigned to receive treatment (albendazole) or a placebo. The outcome variables included growth, tests of reading, spelling and arithmetic, and school attendance. After 6 mo of treatment, there was no significant main effect on any of the outcomes. However, there were significant treatment-by-infection intensity interactions with spelling (P < 0.05) and body mass index (P < 0.01), and a significant treatment-by-stunting interaction with school attendance (P < 0.01). In spelling, the children with heavy infections showed improvements with treatment that approached significance (P = 0.06), whereas those with lower intensities did not. However, the children with lower infection intensities had increased body mass index with treatment (P = 0.02), although there was no difference in children with heavy infections. In school attendance, the stunted children improved with treatment (P < 0.04), whereas there was no difference in the nonstunted children. These findings suggest that in the sample of Jamaican children examined, the treatment of T. trichiura was more likely to benefit school performance in children of poor nutritional status and those with heavy infections, and to improve weight gain in children with lighter infection intensities.

Trichuris trichiura infection and cognition in children: results of a randomized clinical trial

The effects of mild to moderate infections of Trichuris trichiura on cognitive functions were investigated in Jamaican children aged 7 to 10 years. In all, 189 infected children and 100 uninfected classmates were studied. The infected children were randomly assigned to receive treatment (albendazole) or a placebo. All children were given cognitive tests on enrolment and 14 weeks later. These included verbal fluency (generation of ideas), digit span (working memory), number choice (speed of processing of visual stimuli), visual search (sustained attention) and a French Vocabulary test (paired-associate learning). At baseline, the infected children had lower scores than the uninfected ones in fluency (P = 0.01), search (P = 0.02) and French (P = 0.01). Treatment effects were examined among infected children and there was no significant treatment effect for any of the tests. However, there was a significant treatment by weight-for-age interaction in fluency (P < 0.05). The children with low weight-for-age (Z-score < -1) improved with treatment while there was no improvement with treatment among the other children. We concluded that treatment of children with mild to moderate T. trichiura infections using albendazole produces little benefit in cognition if they are adequately nourished; however, undernourished children are more likely to benefit.

Iron status of schoolchildren with varying intensities of Trichuris trichiura infection

The relationship between varying intensities of Trichuris trichiura infection and iron status was examined in Jamaican schoolchildren, aged 7 to 11 years. A total of 409 children was identified with T. trichiura (epg > 1200). A control group comprised 207 uninfected children who were matched by school and class to every pair of infected subjects. Blood samples were obtained from 421 children: 264 infected and 157 controls. Compared to the rest of the children, those with heavy infections (epg > 10,000) had significantly lower (P < 0.05) Hb (11.5 +/- 1.3 vs. 12.1 +/- 1.1 g/dl), MCV (78.6 +/- 6.3 vs. 81.2 +/- 5.5 fl), MCH (26.2 +/- 2.9 vs. 27.5 +/- 2.5 pg) and MCHC (33.2 +/- 1.5 vs. 33.9 +/- 1.4 g/dl). Similarly, the prevalence of anaemia (Hb < 11.0 g/dl) amongst heavily infected children (33%) was significantly higher (P < 0.05) than the rest of the sample (11%). These differences remained significant after controlling for confounding variables including socio-economic status, age, gender, area of residence and the presence of Ascaris infections. Differences in red cell count, ferritin, and free erythrocyte protoporphyrin were not statistically significant and showed no association with the infectious load. These results suggest that in the Jamaican children studied, iron deficiency anemia is associated with Trichuris infections over 10,000 epg, but not with less intense infections.

Tissue specificity and mechanism of vitamin D receptor up-regulation during dietary phosphorus restriction in the rat

Dietary phosphorus restriction up-regulates intestinal vitamin D receptor (VDR), but the tissue specificity of the up-regulation and the mechanism of receptor accumulation remain unknown. Therefore, the effects of low phosphorus diet (LPD) on VDR content in intestine, kidney, and splenic monocytes/macrophages were examined. Male Sprague-Dawley rats weighing 50-100 g were fed a normal diet (NPD; 0.6% Ca, 0.65% P) as controls followed by an LPD (0.6% Ca, 0.1% P) for 1-10 days (D1-D10). LPD rapidly decreased serum P levels by D1 from 11.11 +/- 0.19 mg/dl (mean +/- SE) to 4.98 +/- 0.37 mg/dl (n = 9). LPD increased total serum Ca from 10.54 +/- 0.09 mg/dl to 11.63 +/- 0.15, 12.17 +/- 0.15, and 12.39 +/- 0.18 mg/dl by D1, D2, and D3, respectively, and then remained stable. Serum 1,25-(OH)2D3 rapidly increased from 123 +/- 5.4 pg/ml to 304 +/- 35 pg/ml by D1, reached a plateau through D5, and then gradually increased to 464.9 +/- 27.7 pg/ml by D10. Intestinal VDR quantitated by ligand binding assay increased 3.5-fold from 169.6 +/- 13.7 fmol/mg of cytosol protein in rats fed NPD (n = 12) to a peak of 588.3 +/- 141.88 fmol/mg of protein by D3 (n = 6; p < 0.001) and then decreased to a plateau level of 2.5-fold greater than NPD (p < 0.05) during D5 to D10. In contrast, LPD did not up-regulate kidney or splenic monocyte/macrophage VDR. Northern blot analysis showed that intestinal VDR mRNA increased 2-fold by D2 (n = 3) of LPD and then gradually decreased to control levels after D5. In contrast, kidney VDR mRNA levels did not change during the first 5 days of P restriction and then subsequently decreased to 50% of NPD controls. The results of these studies indicate that VDR up-regulation during dietary phosphorus restriction is tissue-specific and that the mechanism of the up-regulation is time-dependent. Acutely (D1-D5), phosphorus restriction up-regulates intestinal VDR through increased VDR gene expression, whereas chronic (D5-D10) phosphorus restriction appears to alter VDR metabolism through nongenomic mechanisms that are consistent with prolongation of the half-life of the receptor. The nature of the tissue-specific regulation of VDR during phosphorus restriction remains to be determined.

Geohelminth infections in school-aged children in Jamaica

There is concern that geohelminthiasis may adversely affect the growth and development of children. The relevance of this in the Caribbean is unclear since in many territories the prevalence of geohelminths is unknown. We report the results of three surveys conducted in Jamaican primary schools located in areas at high risk for geohelminthiasis. The first was conducted in 12 Kingston schools and comprised children in grades 2 to 5 (aged 7 to 10 years). The second and third surveys were conducted in rural areas with children in grades 2 to 5 and grades 4 and 5, respectively. Overall, 9244 children provided stool samples for analysis. The prevalence of Trichuris trichiura ranged from 42% to 47% among the surveys while that for Ascaris lumbricoides ranged from 15% to 37%. Children in grades 2 and 3 had lower T. trichiura prevalences than those in grades 4 and 5 in the first and second surveys (p < 0.05 and p < 0.005, respectively). In the second survey only, children in grades 2 and 3 had a lower prevalence of A. lumbricoides than those in grades 4 and 5 (p < 0.005). Most infections were light with approximately 1% of the sample having heavy egg densities.

Loss of parathyroid hormone-stimulated 1,25-dihydroxyvitamin D3 production in aging does not involve protein kinase A or C pathways

Intestinal calcium absorption declines with aging as a result of decreased renal 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] biosynthesis. At least part of the decline in 1,25-(OH)2D3 may be due to acquired resistance to parathyroid hormone (PTH) stimulation of renal 25-hydroxyvitamin D1-hydroxylase (1-OHase) activity. To test whether aging rats can increase 1,25-(OH)2D3 production in response to PTH, male rats of the same litter were fed a normal Ca diet and were sacrificed at 175-225 g (young rats) or 3 months later at 350-425 g (aging rats). At sacrifice, basal serum 1,25-(OH)2D3 levels (88 +/- 16 versus 49 +/- 8 pg/ml, P < 0.05) and in vitro renal proximal tubule 1-OHase activity (178 +/- 15 versus 77 +/- 5 pmol/mg protein/5 minutes, n = 6, P < 0.001) were lower in aging animals. rPTH-(1-34) (10(-11) or 10(-7) M) increased in vitro 1,25-(OH)2D3 secretion by perifused renal proximal tubules from young but not aging rats. For young and aging rats, rPTH-(1-34) (10(-7) M) increased proximal tubule cAMP-dependent protein kinase (PKA) activity, and lower concentrations (10(-11) M) stimulated translocation of protein kinase C (PKC) activity from cytosolic to soluble membrane proximal tubule cell fractions. The results of this study show that PTH activation of 1,25-(OH)2D3 production may involve both signaling pathways, with the PKC pathway responsive to lower concentrations of the hormone. The acquired resistance to PTH stimulation of 1,25-(OH)2D3 production in aging appears not to involve the hormonal activation of PKA or PKC.

Structure-function requirements of parathyroid hormone for stimulation of 1,25-dihydroxyvitamin D3 production by rat renal proximal tubules

PTH stimulates synthesis and secretion of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] in renal proximal tubule cells through activation of the protein kinase-A (PKA) or the protein kinase-C (PKC) signaling pathway. The relative contribution of the two transducing systems was explored using PTH fragments with selective activation of either PKA or PKC. Rat renal proximal tubules were isolated by Percoll centrifugation, and PKA and PKC activities were measured after treatment with synthetic fragments and analogs of PTH. Rat PTH-(1-34), [Nle8,Nle15,Tyr34]bovine PTH-(3-34), and human PTH-(13-34) increased PKC activity in a dose-dependent manner. All fragments tested stimulated PKC at physiological concentrations (10(-11)-10(-10) M). Rat PTH-(1-34) (10(-7) M) increased PKA activity 4.5-fold, but other fragments failed to stimulate PKA between 10(-12)-10(-6) M. Human PTH-(28-34) stimulation of PKC was variable from experiment to experiment. All four PTH fragments tested increased 1,25-(OH)2D3 secretion by perifused renal proximal tubules at the lowest concentrations that stimulated PKC activity. The adenylate cyclase inhibitor 2',5'-dideoxyadenosine (10(-4) M) reduced PTH-(1-34)-stimulated PKA activity by 60%, but failed to block the rise in 1,25-(OH)2D3 secretion. The results of these studies demonstrate that PTH fragments that contain the PKC translocating domain stimulate 1,25-(OH)2D3 secretion, whereas elimination of the PKA activation domain does not alter the potency of the analogs' 1,25-(OH)2D3-stimulating activity. These results support the concept that PKC translocation may be required for PTH stimulation of 1,25-(OH)2D3 secretion.

Reduction of phytic acid in soybean products improves zinc bioavailability in rats

The inhibitory effect of phytic acid in soybean products on zinc bioavailability was evaluated in two experiments in rats. In Experiment 1, soybean flours containing different natural phytic acid levels produced by sand culture techniques that limited phosphorus during growth of the soybean plants were formulated into diets. The rats fed a higher phytic acid level diet had lower food intake, depressed weight gain, and lower tibia zinc gain (P < 0.05). A negative, linear relationship between tibia zinc gain and dietary phytic acid level was found. In Experiment 2, two commercially produced soybean isolates containing either normal phytic acid level or a reduced level were formulated into diets. Slope ratio analysis revealed that relative zinc bioavailability from phytic acid-containing soybean isolate-based diets was significantly reduced (P < 0.05) compared with control diets. Reduced phytic acid soybean isolate-containing diets resulted in a significant increase of zinc bioavailability compared with normal phytic acid diets (P < 0.01). These results coupled with other reports indicate that phytic acid is the primary inhibitory factor in soybean products that results in reduced zinc bioavailability and that phytate reduction in soybean protein increases zinc bioavailability.

Mechanisms of growth inhibition by antiestrogens and progestins in human breast and endometrial cancer cells

Marked changes in both growth factor and proto-oncogene expression occur due to treatment of hormonally-responsive human cancers with progestins and antiestrogens. In human endometrial cancer cell lines the antiproliferative effects of progestins and antiestrogens in a particular cell line appear to be associated with similar effects on growth factor and/or proto-oncogene expression. This suggests that although these compounds initially interact with different steroid hormone receptors, the molecular mechanisms of their growth inhibition may be essentially similar. In the case of human breast cancer cell lines, however, the effects of progestins and antiestrogens on gene regulation are often different, suggesting that the molecular mechanisms of progestin and antiestrogen growth inhibition may be essentially dissimilar.

Differential regulation of c-myc by progestins and antiestrogens in T-47D human breast cancer cells

In order to investigate further the mechanisms associated with growth inhibition of human breast cancer cells by progestins and nonsteroidal antiestrogens, their effect on c-myc gene expression in T-47D-5 and T-47D cells has been investigated. The c-myc mRNA levels were differentially regulated by the synthetic progestin, medroxyprogesterone acetate and the nonsteroidal antiestrogen, monohydroxytamoxifen, in both cell lines. Antiestrogen treatment caused a persistent decrease in c-myc mRNA levels while the progestin caused a more complex response. Initially c-myc mRNA levels increased approx. 2-fold, this was followed by a decrease and then partial recovery. The end result, however, of each of these treatments is decreased cell number.

Mechanisms involved in the evolution of progestin resistance in human breast cancer cells

The emergence of resistant cells reduces the efficacy of many forms of drug therapy in human breast cancer. In order to understand some of the possible mechanisms by which hormonally dependent human breast cancers develop resistance to progestin therapy we have developed a human breast cancer cell line (5-RP) which is resistant to the growth inhibitory effects of progestins in culture. These cells routinely grow in 10 microM medroxyprogesterone acetate (MPA). The cell line was developed from T-47D-5 human breast cancer cells by stepwise selection in increasing concentrations of MPA. The progestin-resistant phenotype was relatively stable as assessed by the removal of MPA from the medium for varying periods of time. 5-RP cells passaged in the absence of MPA were still essentially insensitive to the growth inhibitory effects of MPA for at least 22 passages. Even at 53 passages out of the drug the 5-RP line was still less sensitive than the original T-47D-5 parent line. Transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) receptor mRNA were both increased in the 5-RP line compared to the T-47D-5. Consistent with increased TGF-alpha expression, the EGF receptor measured by ligand binding was decreased. When the cells were removed from MPA, TGF-alpha expression declined gradually, but EGF-receptor mRNA levels increased, as did EGF-binding activity. These cells remained estrogen and progesterone receptor positive. Although progestins did not downregulate estrogen receptor expression, they did downregulate progesterone receptor expression in the 5-RP line. The progesterone receptor level of the 5-RP line, in the absence of MPA, was approximately 58% of that found in T-47D-5 cells, even after MPA had been removed for long periods of time. This decrease in receptor level was reflected in decreased ability to respond to progestins as assessed by the decreased ability of MPA to activate expression of both an endogenous gene (EGF receptor) as well as a transiently transfected progestin-responsive gene (MMTV-TK-CAT). Progestin resistance in the 5-RP cell line appears to be multifactorial, involving both increased growth factor expression and decreased receptor levels. It is likely, however, that these two aspects do not account entirely for the progestin-resistant phenotype and as yet other unidentified mechanisms may also be involved.

The rate of ingestion of Ascaris lumbricoides and Trichuris trichiura eggs in soil and its relationship to infection in two children's homes in Jamaica

The rate of exposure to geohelminth infection of children living in 2 institutions in Jamaica, West Indies, was estimated from the product of their rates of ingestion of soil and the density of parasite eggs in the environment. The estimated mean rate of egg ingestion was 9-20 Ascaris lumbricoides eggs and 6-60 Trichuris trichiura eggs per year, although the distribution was highly overdispersed so that some individuals had an estimated annual exposure of several hundred eggs. The estimated individual rates of exposure correlated significantly with the observed worm burdens in children at one of the homes, but not at the other. It is suggested that the susceptibility of the children and the distribution of infective stages in the environment may be important in determining the relationship between exposure and the rate of acquisition of infection.

Epidermal growth factor: receptor and ligand expression in human breast cancer

The epidermal growth factor (EGF) gene is expressed by most human breast cancer cell lines as well as 83% of human breast cancers in vivo. Furthermore, EGF mRNA is detectable in normal human breast tissue. These data suggest that EGF may have a functional role in both normal and neoplastic human breast tissue. Expression of EGF was generally highest in steroid receptor positive human breast tumor biopsies and cell lines. EGF expression was increased by progestins in T-47D and ZR 75 human breast cancer cells. Furthermore, progestins specifically increased the level of TGF-alpha and EGF-receptor mRNA in T-47D cells. Under these same conditions progestins inhibit growth of the cells. Regulation of expression of EGF, TGF-alpha and the EGF-receptor is unlikely to be directly related to the mechanism of progestin induced growth inhibition in T47-D cells. T-47D-5 cells are more sensitive than T-47D cells to progestin and antiestrogen induced growth inhibition. T-47D-5 cells do not express EGF and contain very low levels of TGF-alpha mRNA. The higher level of EGF and TGF-alpha expression in T-47D cells may be one mechanism by which these cells decrease their sensitivity to growth inhibition by progestins and antiestrogens.

Quantitative assessment of contamination of soil by the eggs of Ascaris lumbricoides and Trichuris trichiura

This study used a method of retrieving eggs from soil to examine the spatial and temporal dynamics of soil contamination with geohelminth eggs. The level of soil contamination in two children's homes in Jamaica was determined before and after further soil contamination was prevented by chemotherapy. The home which had higher human infection levels also had a higher prevalence and density of eggs in soil. The spatial distribution of the eggs in soil was overdispersed in the home with higher levels of infection, and underdispersed in the other, perhaps due to the low density of eggs. At both localities, the proportion of soil samples containing eggs and the density of eggs in soil declined over a two-month period. The results suggest that geohelminth eggs are rapidly depleted from the surface of tropical soils in the absence of continuing sources of contamination.

Control of geohelminths by delivery of targeted chemotherapy through schools

This study describes the age-targeted chemotherapeutic control of geohelminthiasis in the total population (n = 11,500) of the island of Montserrat, West Indies. The intervention programme involved the treatment with single dose albendazole of all children aged 2-15 years (approximately 2500) in 4 sequential cycles at intervals of 4 months. Infection status was monitored by an initial coprological survey of an age-stratified sample (11.5%) of the population, and by surveys of smaller samples (4-5%) after 2 and 4 cycles of treatment (7 and 15 months respectively). The programme delivered treatment to greater than 90% of the target population in each cycle, and reduced the prevalence and intensity of Ascaris lumbricoides and Trichuris trichiura infection in the target age-class. A decline in infection was also observed in the 16-25 year age-class, even though less than 4% of adults received treatment. The study demonstrates that chemotherapy targeted only at children can be implemented within an existing health infrastructure, and can achieve an overall reduction in the prevalence and intensity of geohelminth infection.

Quantitative assessment of geophagous behaviour as a potential source of exposure to geohelminth infection

The most common form of pica, geophagy, has direct adverse nutritional effects and also exposes children to soil-borne infection. Existing methods for assessing geophagy are either inappropriate for field use (radiology) or unreliable (reporting). A new method is described, based on the measurement of soil-derived silica in stools. More than 90% of silica is excreted within one gut transit period of ingestion. The amount excreted is proportional to the amount ingested. Faecal levels of dietary silica (less than 2% dry wt stool) can be distinguished from levels due to geophagy (up to 25% dry wt stool). Studies in 2 children's homes in Jamaica showed that 33% and 66% of children were geophagous, ingesting up to 10 g soil day-1. The geophagy of less than 20% of the children accounted for greater than 60% of the total soil ingested. This overdispersion of exposure to soil-borne infection may contribute to the observed aggregation of geohelminth infection.

Failure of exogenous progestogens to block dexamethasone-induced prostaglandin F release from the uterus of the late-pregnant cow

The effect of exogenous progesterone or megestrol acetate (MGA) on cervical extensibility and on the concentrations of prostaglandin (PG) F in utero-ovarian plasma and progesterone, estrone sulphate and unconjugated estradiol-17 beta concentrations in jugular plasma was studied over Days 238-242 in pregnant cows given intrafetal infusions of dexamethasone to induce premature delivery. All 11 cows used in the study were given continuous intrafetal infusions of dexamethasone at a rate of 3.3 mg/day to induce premature labor. Progesterone was infused continuously at a rate of 400 mg/day for 10 day into the jugular vein of 3 of 11 cows while another 3 were given MGA at a rate of 20 mg/day. In the cows given dexamethasone alone premature parturition was induced in 2.5-4.5 days and all calves were born alive and well. However, in the progestogen-treated cows, dexamethasone failed to induce premature delivery. The cervix of these cows remained firm and unyielding during the time of the progesterone infusion. Following the withdrawal of exogenous progestogens the cervix became soft and compliant and the cows delivered within 0.5-1.5 days, but only 2 of the 6 calves were alive at birth. Hormone changes in the cows given intrafetal infusions of dexamethasone included a marked rise in utero-ovarian PGF and a concomitant decline in jugular progesterone concentrations. Plasma concentrations of estrone sulphate and estradiol-17 beta showed a small increase before delivery. An increase in utero-ovarian PGF concentrations was also observed in all of the progestogen-treated cows, although there was considerable individual variation in the timing of the PGF surge. The plasma concentrations of estrone sulphate and unconjugated estradiol-17 beta levels in the progestogen-treated cows showed the same general trend, with the levels increasing within 1-2 days of starting the dexamethasone infusion and then falling before delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Antisera reactive directly to estrone sulfate

Derivatives of estrone were prepared and linked to bovine serum albumin or its methyl-esterified form to produce immunogens which were effective in raising antisera to estrone sulfate. The most effective was estrone-3-methylphosphonothioate, electrostatically complexed with methylated bovine serum albumin. The ionically combined hapten functioned as an antigenic determinant as do covalently bound haptens when administered to sheep in emulsions with Freund's complete adjuvant. Estrone-3-phosphate covalently or electrostatically linked to bovine serum albumin also produced antisera reactive to estrone sulfate. Estrone sulfate itself, after electrostatically complexing to methylated bovine serum albumin and administration with Freund's complete adjuvant to sheep, was ineffective in producing antisera. The sera which had workable titres to estrone sulfate showed considerable cross-reaction with free estrone but was otherwise highly specific with little or no reaction with other steroid sulfates, glucosiduronates or other free steroids. Radioimmunoassay curves using [6,7-3H]-estrone sulfate were highly sensitive and were effective in the range of 5-250 pg estrone sulfate.