Association between Serum Progastrin Biomarker Level and Gastric Cancer

BACKGROUND AND OBJECTIVE

gastric cancer is the fifth most prevalent cancer and the fourth cause of death because of cancer. In Iran, northern and northwestern regions are considered gastric cancer hot spots. Identifying serum biomarkers could be helpful in early diagnosis of patients with gastric adenocarcinoma (GAC). Increase in progastrin level has been reported in different cancers. Given the diagnostic value of this biomarker, this study aimed to determine the diagnostic role of progastrin serum biomarker in patients with gastric cancer.

METHODOLOGY

In this case-control study, forty patients with gastric cancer who were diagnosed by endoscopy and pathologic findings and visited Mazandaran Comprehensive Cancer Center. The participants had received no treatment yet and entered this study. The participants in case group were compared with the control group including forty-two individuals with no history of gastrointestinal cancer in their first-degree relatives and visiting the lab for routine tests. Progastrin serum level was assessed using ELISA kit. The Kruskal-Wallis test and Mann Whitney test, both non-parametric) were used for statistical analysis and the relation between the variables was examined using Pearson's correlation coefficient at 95% confidence level in SPSS 16.

FINDINGS

In this study, progastrin serum level was significantly higher in patients with gastric cancer compared with normal participants (P = 0.035). Progastrin serum level had no significant relation with tumor clinicopathologic parameters (p-value > 0.05).

CONCLUSION

Increase in progastrin may be utilized as a predictive factor for gastric cancer.

Late umbilical cord clamping, neonatal hematocrit and Apgar scores: a randomized controlled trial

OBJECTIVE

Based on current evidence, there is a little agreement on the best timing for after birth umbilical cord clamping. This study was designed to compare the impact of using two different times for cord clamping on hematocrit concentration and Apgar scores of the neonate.

STUDY DESIGN

Fifty-six healthy full-term vaginally born neonates were allocated to early (10 seconds after delivery) and late (3 minutes after delivery) umbilical cord clamping groups in this randomized clinical trial. We recorded the length of the 3rd stage of labor and Apgar score at 5 minutes. Infant's hematocrit was measured at 2 and 18 hours of age.

RESULTS

Neonatal hematocrit differed between the two groups. Late cord clamping group had greater hematocrit at 2 hours (45.5 ± 4 vs. 49.5 ± 4.4, P = 0.0003) and 18 hours (47.7 ± 5.5 vs. 52.9 ± 4.3, P = 0.0002). Apgar scores at 5 minutes (9.3 ± 0.6 vs. 9.4 ± 0.6, p = 0.5) and duration of delivery 3rd stage (10.2 ± 3.7 min vs. 8.9 ± 5 min, P = 0.2) did not differ between early and late cord clamping groups respectively.

CONCLUSION

Late cord clamping leads to a significant increase in the hematocrit of the neonate but it does not have effects on Apgar score and duration of the 3rd stage of labor.

Effect of formulation and processing variables on the characteristics of tolmetin microspheres prepared by double emulsion solvent diffusion method

The aim of this study was to evaluate microencapsulated controlled release preparations of tolmetin sodium using ethylcellulose as a retardant material. Microspheres were prepared by using water-in-oil-in-oil (W/O₁/O₂) double-emulsion solvent diffusion method, using different ratios of ethylcellulose to tolmetin sodium. Span 80 was used as the droplet stabilizer and n-hexane was added to harden the microspheres. The prepared microspheres were characterized for their micromeritic properties, drug content, loading efficiency, production yield, and particle size. Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray powder diffractometry and scanning electron microscopy were used to characterize microparticles. The in vitro release studies were performed in pH 1.2 and 7.4. The prepared microspheres were spherical in shape. The drug-loaded microspheres showed near to the theoretical of entrapment and release was extended up to 24. The X-ray diffractogram and differential scanning thermographs showed amorphous state of the drug in the microspheres. It was shown that the drug: polymer ratio, stirring rate, volume of dispersing medium and surfactant influenced the drug loading, particle size and drug release behavior of the formed microparticles. The results showed that, generally, an increase in the ratio of drug: polymer (0.5:1) resulted in a reduction in the release rate of the drug which may be attributed to the hydrophobic nature of the polymer. The in vitro release profile could be modified by changing various processing and formulation parameters to give a controlled release of drug from the microparticules. The release of tolmetin was influenced by the drug to polymer ratio and particle size and was found to be diffusion and erosion controlled. The best-fit release kinetic was achieved with Peppas model.

Eleven years prospective follow-up of the tension-free vaginal tape procedure for treatment of stress urinary incontinence

The aim of this study was to evaluate the long-term effectiveness and safety of the tension-free vaginal tape (TVT) procedure. In a Nordic three-center prospective observational cohort study, 90 women with primary stress incontinence had a TVT operation performed in local anesthesia. Assessment included a 24-h pad test, a stress test, physical examination, and a visual analog scale for assessing the degree of bother. Patient's global impression of cure was obtained, and condition specific quality of life questionnaires were used. Seventy-seven percent of the initial cohort of 90 women and 89% of those alive and capable of cooperating were assessed 11.5 years after the TVT operation. Ninety percent of the women had both a negative stress test and a negative pad test being objectively cured. Subjective cure by patients global impression was found in 77%, 20% being improved and only 3% regarded the operation as a failure. No late-onset adverse effects of the operation were found, and no case of tape erosion was seen. The TVT procedure is safe and effective for more than 10 years.

Expression of estrogen receptor-? and -? in anterior vaginal walls of genuine stress incontinent women

Our objective was to study the expression of estrogen receptor (ER) isoforms, ER-alpha and ER-beta, in the anterior vaginal wall of menopausal and fertile women with genuine stress incontinence (SI) by immunohistochemistry and Western blot analysis. Eighteen menopausal women with SI who either were or were not taking estrogen/progestin replacement therapy and 14 fertile women with SI who either were or were not taking contraceptives were enrolled in the study. Biopsies from the suburethral anterior vaginal wall were obtained at tension-free vaginal tape (TVT) operation. Monoclonal antibody to ER-alpha and polyclonal antibody to ER-beta were used to stain frozen sections of vaginal tissue. The receptor expressions were scored based on percentage of positive cells. ER-alpha was detected in vaginal epithelial, stromal and smooth muscle cells. In menopausal SI women ER-alpha was detected significantly more frequently in the vaginal walls of estrogen/progestin-treated patients than in those who were untreated. Fertile SI women had significantly higher expression of ER-alpha than menopausal SI women. ER-alpha was not observed in vaginal blood vessels. ER-beta was detected in epithelial and vascular smooth muscle cells of the vagina. No significant difference in ER-beta expression was observed between different groups of patients. The expression of ER-alpha was not correlated with that of ER-beta. Both ER-alpha and -beta were detected, indicating a potential role for both types of estrogen receptor in the human vaginal wall. The expression of ER-alpha, but not of ER-beta, in menopausal SI women was regulated by estrogen/progestin replacement therapy. The presence of ER-beta in vaginal vascular smooth muscle cells raises the possibility of vascular effects of estrogen on the human vaginal wall.

Long-term results of the tension-free vaginal tape (TVT) procedure for surgical treatment of female stress urinary incontinence

In a prospective long-term Nordic multicenter study, 90 consecutive patients who had a tension-free vaginal tape (TVT) operation performed because of stress urinary incontinence were evaluated according to a strict protocol after approximately 5 years (range 48-70 months). Eighty-five patients could be evaluated according to the protocol. Another 5 elderly patients had to be interviewed by telephone at the final check-up after 5 years. The study protocol involved pre- and postoperative objective and subjective evaluation. The median follow-up time was 56 months. Seventy-two of the 85 patients who were fully evaluated (84.7%) were both objectively and subjectively completely cured. Another 9 patients (10.6%) were significantly improved and 4 (4.7%) were regarded as failures. No patient complained of long-term voiding difficulties and there were no signs of defective healing or rejection of the tape material. All patients had suffered from primary stress incontinence, and 25 also had preoperative complaints of urge. In 14 of these (56%) the urge symptoms were relieved postoperatively. We conclude that the TVT procedure seems to fulfil the expectations of high long-term cure rates, as suggested in previous short-term reports.

Tension-Free vaginal tape (TVT) in stress incontinent women with intrinsic sphincter deficiency (ISD)--a long-term follow-up

In a prospective long-term study 49 women with stress incontinence and ISD (intrinsic sphincter deficiency) were followed for a mean of 4 years (range 3-5) after TVT operation. Preoperatively all patients underwent urodynamic investigations, quality of life evaluation, a 24-hour pad test and a gynecologic examination to properly verify the incontinence symptoms. The same protocol was used for postoperative evaluation. The mean age of the women was 66 years (+/- 11) and mean parity 2 (range 0-4). A standard TVT operation was performed under local anesthesia. At the postoperative evaluations 36 patients (74%) were completely cured of their incontinence problems. In addition, 6 women (12%) were significantly improved. In 7 patients (14%) no improvement was found. The majority of these not cured patients were >70 years of age and had urethral resting pressure of <10 cmH2O. Few intra- and postoperative complications occurred. It is concluded that TVT can be used for surgical treatment of patients with ISD and stress incontinence. However, older patients (>70 years) with a very low resting urethral pressure and an immobile urethra seem to constitute a risk group where TVT surgery is less successful.

Tension-Free vaginal tape (TVT) in women with mixed urinary incontinence--a long-term follow-up

In a prospective long-term study we evaluated the effect of TVT surgery in 80 women suffering from mixed urinary incontinence. Their mean age was 59 +/- 11 years with a mean parity of 2 (range 0-6). Mean follow-up was 4 years (range 3-5). The preoperative evaluation included a 24-hour pad test, quality of life evaluation, gynecologic examination and urodynamic investigations, including simultaneous urethrocystometry. From the patient history 96 patients were initially tentative candidates for TVT operation. Sixteen of these had only minor symptoms and signs of stress incontinence but significant symptoms and signs of detrusor instability, and were not considered suitable for TVT surgery. In the remaining 80 women the urodynamic investigation with filling urethrocystometry demonstrated stress incontinence and urge incontinence concomitant with urethral relaxation and/or 'premature micturition' reflex. At the postoperative long-term follow-up 85% of the patients were completely cured. Another 4% were significantly improved. In 11% of the patients the operation failed. Few intra- or postoperative complications occurred. Based on these results, we conclude that TVT surgery can be used for treatment of female mixed urinary incontinence. A proper urodynamic assessment is recommended before surgery is performed.

Tension-Free vaginal tape (TVT) in women with recurrent stress urinary incontinence--a long-term follow up

In a prospective long-term follow-up study we evaluated the results of TVT surgery in 34 women with recurrent stress urinary incontinence in whom previous traditional surgical procedures had failed. The women were followed for a mean of 4 years (range 3-5) after TVT surgery. The mean age was 58.9 +/- 10 years and the mean parity 2 (0-4). Pre- and postoperative evaluation was performed according to a protocol which included gynecologic examination, urodynamic investigations, quality of life evaluation and 24-hour pad test. According to the protocol 28 patients (82%) were cured, 3 (9%) were significantly improved, and the operation failed in 3 cases (9%). There were no significant intra- or postoperative complications. All patients were operated on under local anesthesia with a short hospitalization and had no long-term postoperative voiding problems.

Multiple connexins localized to individual gap-junctional plaques in human myometrial smooth muscle

The synchronous contractions of the uterus in labour depend on electrical coupling of myometrial smooth muscle cells by gap junctions. In the human myometrium, gap junctions are scarce in the non-pregnant uterus, but become abundant at term in preparation for labour. We have previously demonstrated that in the human myometrium at term, three different gap-junctional proteins are expressed, connexins 43, 45, and 40. These connexins are known to have distinctive functional capacities in in vitro expression systems but whether, in the human myometrium in vivo, they are co-assembled into the same gap junction or form different types of gap junction has previously been unclear. By applying triple immunogold labelling to sections of Lowicryl-embedded tissue for electron microscopy, together with complementary immunoconfocal microscopy, we demonstrate here that connexins 43, 45, and 40 are commonly present as mixtures within the same gap-junctional plaque. While all gap junctions contain connexin43, the relative signal for each connexin type varies between individual junctions. The presence within single gap-junctional plaques of three different connexins, each with the potential for conferring distinctive channel properties, suggests an inherent versatility for modulation of smooth muscle cell intercellular communication properties during human parturition.

A three-year follow up of tension free vaginal tape for surgical treatment of female stress urinary incontinence

OBJECTIVE

To study the long term results of tension-free vaginal tape, a new ambulatory surgical procedure for treatment of female stress urinary incontinence.

STUDY DESIGN

A prospective open study using a standardised protocol for pre- and post-operative evaluation.

PARTICIPANTS

Fifty consecutive women participated in the study. All suffered from genuine stress incontinence. The mean age was 57 years (SD 11), 42 women (84%) were multiparous, 8 (16%) nulliparous.

SURGICAL METHOD

Tension-free vaginal tape implies the implantation of a prolene tape around mid-urethra via a minimal vaginal incision. The procedure is carried out under local anaesthesia, allowing the surgeon to check intra-operatively that continence has been obtained.

RESULTS

All the women except one could be operated on an ambulatory basis under local anaesthesia. Mean operation time was 29 minutes (range 1647). Ninety percent of the women were able to micturate spontaneously within 24 hours with insignificant residual volumes. In another 10% of the women an in-dwelling catheter had to be used temporarily. There was no need for long term postoperative catheterisation (> 14 days). Post-operative evaluation was carried out after 2 to 6, 12, 24 and 36 months. According to the protocol, 86% of the women were completely cured and another 11% were significantly improved. No signs of deterioration of the results over time were observed. No defect in healing or rejection of the tape occurred.

CONCLUSION

We consider the tension-free vaginal tape operation to be a safe and effective surgical procedure for the treatment of female urinary stress incontinence. The technique can be considered as an ambulatory procedure performed under local anaesthesia, allowing the majority of the women to be discharged from the clinic the same day or the day after the procedure.

Identification of two further gap-junctional proteins, connexin40 and connexin45, in human myometrial smooth muscle cells at term

The powerful synchronous contractions of the uterus in labor depend on electrical coupling of myometrial smooth muscle cells by gap junctions. In humans and other mammals, gap junctions are scarce in the myometrium of the non-pregnant uterus, but become abundant at term and/or with the onset of labor. Previous work has shown that the gap-junctional protein (connexin) expressed by human myometrial smooth muscle cells is connexin43, the same connexin type that predominates in cardiac muscle. Here we show that two further gap junctional proteins, connexin40 and connexin45, are expressed by the myometrial smooth muscle cells of the human uterus at term. Transcripts encoding the human isoforms of these connexins were demonstrated by Northern blot analysis, and immunoconfocal microscopy enabled precise localization of the corresponding proteins to punctate contact points (i.e., gap junctions) between interacting smooth muscle cells. Double labeling demonstrated that, while some fluorescent spots comprise only connexin43, both connexin40 and connexin45 predominantly colocalize to connexin43-positive fluorescent spots. Triple labeling revealed that where all three connexin types were expressed, they frequently localized to the same gap junction spot. As gap-junctional channels composed of different connexin types have been demonstrated in vitro to have different functional properties, multiple connexin expression may contribute to modulation of gap junction function in human myometrial smooth muscle cells in vivo.

Sex steroid receptors and human parturition

OBJECTIVE

To investigate the correlation between sex steroid hormones and their receptors during normal and dysfunctional labor.

METHODS

Myometrial and decidual biopsies along with maternal and cord blood samples were taken from women with or without labor activity. Estrogen and progesterone receptor contents in myometrium and decidua were determined by enzyme immunoassay, and hormone concentrations were analyzed by radioimmunoassay.

RESULTS

In the lower segment of the uterus, the progesterone receptor concentrations of myometrium were significantly lower in oxytocin-resistant dystocia compared with those of normal labor and before labor (P < .04, P < .005, respectively). No significant difference was found in the estrogen receptors contents in the groups studied. The progesterone receptors of myometrium from the upper segment showed higher concentrations in active labor compared with those before labor and oxytocin-resistant labor (P <.01, P < .05, respectively). Estrogen receptors from the upper segment showed no significant difference in these regards. There was no difference in peripheral and myometrial sex hormone levels in the groups studied.

CONCLUSION

These data suggest that, in the human, 1) oxytocin-resistant labor is associated with low levels of progesterone receptors, 2) estrogen receptors content in myometrium might have no or little relation to labor, and 3) functional labor seems not to be related to a decreased progesterone activity in the myometrium.

Quantitative immunoconfocal analysis of human myometrial gap junction connexin43 in relation to steroid hormone concentrations at term labour

The aim of this study was to quantify gap junction expression in the human myometrium in relation to progesterone and oestradiol concentrations, and to establish whether oxytocin-resistant dystocia is due to an abnormality in gap junction expression. Three groups of patients were investigated: (i) before labour (at term), (ii) normal labour and (iii) oxytocin-resistant dystocia (eight patients per group). For each patient, the concentrations of oestradiol and progesterone in maternal blood and in myometrial tissue were measured, and the number and area of immunostained connexin43 gap junctions per unit volume of tissue determined by quantitative analysis of digital images obtained by confocal microscopy. No significant difference in connexin43 gap junction content was observed between the three patient groups. When all groups were pooled, there was a significant positive correlation (P < 0.05) between the quantity of immunolabelled gap junctions and the oestradiol:progesterone ratio, but there was no significant difference in this correlation between the groups. Gap junction immunolabelling was not correlated with the progesterone or oestradiol concentration in the maternal blood or the myometrium. These data suggest that in human myometrium: (i) dystocia is not due to a reduced level of immunodetectable connexin43 gap junctions, (ii) onset of labour is not associated with a sudden increase in immunodetectable gap junction protein and (iii) gap junctions can be expressed in the presence of high progesterone concentrations.

Effects of progesterone and oxytocin on intracellular elemental composition of term human myometrium in vitro

OBJECTIVE

To study the effects of progesterone and oxytocin on contractile activity related to the intracellular elemental composition of human pregnant myometrium.

STUDY DESIGN

Myometrial strips were mounted in tissue baths and superfused with plain buffer, oxytocin or progesterone. Progesterone was initially added to the tissue bath or at the onset of spontaneous contraction of the strips. The myometrial contractile activities were recorded isometrically and the results were analyzed by a specific computer program. The effects of oxytocin and progesterone on the intracellular elemental composition were studied by X-ray microanalysis in an electron microscope.

RESULTS

The contractile activity in terms of frequency and tonus of the muscle strips was increased by oxytocin and progesterone. This increase was more pronounced if progesterone was added to the bath at the start of the experiment. After 120 min of incubation with oxytocin and progesterone the total intracellular concentration of calcium was significantly higher (P < 0.0001 and P < 0.002, respectively) compared to buffer.

CONCLUSIONS

(i) Oxytocin increases total intracellular calcium concentration concomitant with an increase in uterine contractile activity. (ii) Progesterone increases the myometrial tone and frequency of contractions, simultaneously with an increase in total intracellular calcium.

Myometrial steroid concentration and oxytocin receptor density in parturient women at term

The aim of this study was to measure oxytocin receptor concentration in myometrial tissue from term pregnant women with normal and dysfunctional labor and to relate this concentration to the progress of labor and to the levels of estradiol and progesterone in the same myometrium. Myometrial biopsies were obtained from 50 term pregnant women undergoing cesarean section. The patients were categorized as follows: not in labor, normal labor, successful oxytocin-augmented labor, and oxytocin-resistant labor. Specific binding of [3H]oxytocin to high-affinity sites in membrane preparations from myometrial tissues was determined. Estradiol and progesterone were assayed using tritiated steroids with a sensitive radioimmunoassay technique. Oxytocin receptor density was significantly lower in oxytocin-resistant labor compared to successful oxytocin-augmentated labor (P < 0.04) and to spontaneously active normal labor (P < 0.02). Oxytocin receptor concentration was also significantly lower in non-labor patients compared to normal spontaneous labor (P < 0.01), and successful oxytocin-augmented labor (P < 0.02). There was a positive relationship between the progress of cervical dilatation (cm/h) and oxytocin receptor density in the myometrium (r = 0.408, P < 0.025). The concentration of progesterone and estradiol in the pregnant myometrium did not differ in patients with different types of labor or with the state of uterine contractile activity. Our results suggest that individual myometrial sensitivity is an important determinant of the response to administered oxytocin in humans. Furthermore, myometrial oxytocin receptor expression in vivo seems not be related to ovarian steroid concentration in the myometrium. The low oxytocin receptor density in oxytocin-resistant dystocia needs further investigation.

X-ray microanalysis of myometrium in parturient women at term

The purpose of this study was to investigate the elemental composition of myometrial cells from term parturient women with normal and dysfunctional labour. Myometrial biopsies were obtained from forty-four term pregnant women undergoing Cesarean section. The patients were categorized according to uterine activity as follows: before labour, normal labour, labour successfully augmented by oxytocin, oxytocin-resistant labour, and labour arrested by terbutaline. X-ray microanalysis of freeze-dried sections (16 mu m thick) of the myometrium was carried out. An increase in intracellular phosphorus level (p < .01) was noted in the normal labour group compared to before labour. In patients with normal labour, higher phosphorus (p < .009) and potassium (p < .005) were found compared to oxytocin resistant labour. Patients with oxytocin resistant labour had lower intracellular potassium (p < .0006) and phosphorus (p < .02), and higher chloride (p < .05) and sodium (p < .03) compared to levels found in patients who responded to oxytocin treatment. In dysfunctional (oxytocin-resistant) labour the ion distribution in the myometrial cells might be disturbed. The reduced level of potassium and phosphorus together with the high sodium and chloride levels found in patients with oxytocin resistant labour may be connected to an impairment in sodium-potassium pump and muscle dysfunction, clinically diagnosed as dystocia.

Morphometric analysis of gap junction density in human myometrium at term

In the human myometrium, the formation of gap junctions in the various stages of labor and, in correlation with the concentration of progesterone in the maternal blood, has not been described adequately. The accepted hypothesis that raised concentrations of progesterone in maternal blood in animals prevent the formation of gap junctions was scrutinized in human myometrium. Myometrial tissue was examined by electron microscopy for the presence of gap junctions and analyzed morphometrically in 17 women who had an elective or emergency cesarean operation at the 38th or 39th week of pregnancy. The concentrations of progesterone and estradiol in the maternal and cord blood was measured by means of radioimmunoassay. The frequency and area of gap junctions varied in relation to the presence or absence of labor. In the myometrium of women in labor, gap junctions were most frequent (5.2/1000 microns of cell membrane), their area largest (0.32 microns 2/1000 microns of cell membrane) and their fractional area greatest (0.20%). When the women were not in genuine labor or when contractions were weak, the percentage fractional areas of gap junctions were low (0.020-0.090) and the gap junctions very small. In the pre- and active phases of labor, the concentration of progesterone in maternal blood was significantly higher (p < 0.025 and 0.03 respectively) than in women who were not in labor. Hence, despite high concentrations of progesterone in the maternal and cord blood at term, the myometrium presented numerous gap junctions of relatively large area.

Antitachyphylactic effects of progesterone and oxytocin on term human myometrial contractile activity in vitro

OBJECTIVE

To determine whether progesterone causes any changes in the action of oxytocin on the contractile activity of term human myometrium in vitro.

METHODS

Myometrial biopsies from 13 term pregnant women undergoing cesarean delivery were immediately immersed in Hepes buffer or buffer containing 5 micrograms/mL progesterone. In the laboratory under a stereomicroscope, the specimens were dissected into 1 x 7.5-mm muscle strips. These were mounted into six tissue baths and superfused with Hepes buffer and buffer containing 5 micrograms/mL progesterone, 5 micrograms/mL progesterone plus 10 microU/mL oxytocin, 5 micrograms/mL progesterone plus 100 microU/mL oxytocin, 10 microU/mL oxytocin, and 100 microU/mL oxytocin. Isometric tension was recorded constantly for at least 3 hours.

RESULTS

The frequency of myometrial contractions and tonus increased by superfusion with progesterone, progesterone plus oxytocin, and oxytocin alone compared to buffer. In addition, a gradual decrease in frequency was observed after 60 minutes of contractions with oxytocin alone, whereas progesterone plus oxytocin had no such decrease. The activity area of contractions was greater with 10 microU/mL oxytocin and decreased with progesterone, progesterone plus both concentrations of oxytocin, and 100 microU/mL oxytocin alone, compared to buffer.

CONCLUSIONS

Progesterone stimulated the frequency of contractions and tonus of strips from the lower uterine segment of term human myometrium. A lasting increase in the frequency of contractions was observed with superfusion of progesterone plus oxytocin, suggesting that progesterone counteracted the reaction of tachyphylaxis to oxytocin.

Unexpected stimulatory effect of progesterone on human myometrial contractile activity in vitro

OBJECTIVE

To investigate the effects of continuous exposure of progesterone on contractile activity of term human myometrium in vitro.

METHODS

Myometrial biopsy specimens were obtained from 14 term pregnant women undergoing elective cesarean. The specimens were immediately immersed in Hepes buffer and buffer containing 0.33, 4.1, and 70 micrograms/mL progesterone. Muscle biopsies were dissected along the bundles of smooth muscle under stereomicroscope. These myometrial strips were mounted in tissue baths and superfused with Hepes buffer and buffer containing different concentrations of progesterone.

RESULTS

The progesterone concentration of 0.33 microgram/mL had no significant effect on myometrial contractile activity. The concentrations of 4.1 and 70 micrograms/mL increased the frequency of contractions (P < .01 for each) and tonus (P < .01 for each), decreased the activity area of contractions (P < .01 for each), and delayed the onset of contractions (P < .01 and P < .05, respectively).

CONCLUSION

When the myometrium is not deprived of progesterone, this hormone may have excitatory effects on the frequency of contractions and tonus of the lower uterine segment of term human myometrium.