A benchmark for Monte Carlo simulations in gamma-ray spectrometry Part II: True coincidence summing correction factors

The goal of this study is to provide a benchmark for the use of Monte Carlo simulation when applied to coincidence summing corrections. The examples are based on simple geometries: two types of germanium detectors and four kinds of sources, to mimic eight typical measurement conditions. The coincidence corrective factors are computed for four radionuclides. The exercise input files and calculation results with practical recommendations are made available for new users on a dedicated webpage.

Primary standardization and half-life determination of 225Ac at NRC

A solution of 225Ac was standardized by NRC using the triple-to-double coincidence ratio (TDCR) method. The counting efficiencies were calculated assuming a counting efficiency of 100% for alpha decays and those calculated using the MICELLE2 Monte Carlo code for beta decays and was approximately 500% for the NRC TDCR system. The relative uncertainty for the activity concentration was determined to be 0.25%. This agreed with measurements performed using gamma spectroscopy and a predicted calibration factor for the Vinten 671 ionization chamber as calculated using an EGSnrc model, implementing radioactive decay. Finally, the half-life of 225Ac was determined from long-term measurements using ionization chambers and liquid scintillation counting. The NRC measured half-life for 225Ac was found to be 9.914(4) days and is consistent within an expanded uncertainty coverage of k = 2 with the most recent (Kossert et al., 2020; Pommé et al., 2012) measurements of this decay parameter.

Left atrial appendage remodeling following percutaneous closure with WATCHMAN 2.5 and FLX: insights from the WATCH-DUAL registry

Background

Percutaneous left atrial appendage closure (LAAC) has emerged as a valid option for prevention of thromboembolic events in patients with non-valvular atrial fibrillation and contraindications for oral anticoagulation. The most recent devices have been created to improve the intervention efficiency and to allow the procedure in a wider range of anatomies. The new-generation Watchman FLX (WMFLX) features a new design but its in vivo performances have not been compared to the previous WATCHMAN 2.5 (WM2.5) prosthesis. Hence, the data regarding conformability, compression and device-related LAA remodeling are scarce.

Purpose

To compare the anatomical results of WM2.5 and WMFLX implantation and impact on LAA dimensions.

Methods

This study included LAAC patients from the WATCH-DUAL registry who benefited from a pre- and post-intervention CT scan. The WATCH-DUAL study was a dual center observational study including all the LAAC procedures prospectively collected in local registries from two high-volume centres between November 2017 and December 2020. The LAA and device dimensions were measured in a centralized core lab by 3D CT scan reconstruction methods, focusing on the device landing zone (LZ/defined as the cross section of the appendage that was perpendicular to its axis and connected the circumflex artery to a point 1 to 2 cm inside the LAA).

Results

This analysis included n=107 patients (n=58 WMFLX, n=49 WM2.5). The patients clinical profiles didn't differ, except for a higher proportion of coronary artery disease in WM2.5 group. The LAA dimensions were comparable between groups. There was a significantly higher proportion of chickenwing shapes in the WMFLX patients. The mean device baseline diameter was in the WMFLX compared to the WM2.5 patients (28.8±0.5 vs. 25.7±0.4 mm, p<0.001).

The median delay for CT control was 48 (43–62) days. The LZ area (451 (363–521) vs. 366 (260–459) mm2, p<0.001) and minimal diameter (23.0 (20.7–24.8) vs. 18.7 (15.9–21.8) mm, p<0.001) significantly increased after implantation among patients. The LZ area increase absolute value and percentage were 101 (18–151) mm2 and 28 (4–54) % respectively. The LZ dimensions increase was more pronounced in the WMFLX group: these patients exhibited post LAAC larger LZ area and dimensions compared to the WM2.5 cases. The LAA eccentricity was reduced after implantation: the ratio LZ maximal/LZ minimal diameter significantly decreased for all patients (r=1.28 (1.18–1.40) vs. 1.06 (1.05–1.09), p<0.001). Comparable results were observed in WMFLX and WM2.5 patients.

A multivariable regression analysis demonstrated that baseline LAA length, baseline LZ eccentricity and WM FLX use were independent predictors of LAA remodeling/dimensions increase.

Conclusion

LAA dimensions increased over time at the site of WM prosthesis implantation suggesting a local positive appendage remodeling after procedure. This phenomenon appears to be more pronounced with the WMFLX device.

Funding Acknowledgement

Type of funding sources: None.

Production of a carrier-free standard 56Mn source for the NRC manganese salt bath

The National Research Council (NRC) of Canada's primary method for emission rate for radionuclide neutron sources utilizes a manganese salt bath which was last calibrated in the 1960s. At that time, an NRC RaBe neutron source was used to irradiate a solution of calcium permanganate to take advantage of the Szilard-Chalmers effect in producing the bulk ⁵⁶Mn material for standardization and calibration of the bath. When attempting to repeat this exercise, a small amount (~100 kBq) was produced. This amount was sufficient for the standardization process but did not yield enough material to calibrate the bath to a sufficient level of precision. Improvements upon the previous separation scheme adopted at NRC for the separation of the ⁵⁶Mn from the bulk irradiated material included the rinsing of the ⁵⁶Mn dioxide precipitate using a mixture of sulfuric acid and hydrogen peroxide. While these improvements made in the separation chemistry improved the yield of ⁵⁶Mn extraction from 60% to above 95% the maximum amount of activity was still quite low. Hence in March of 2018, the SLOWPOKE-2 Facility at the Royal Military College in Kingston, ON, was used to irradiate three vials of KMnO₄ in solution. An estimated 2 GBq was produced and sent to NRC, from which the extraction procedure recovered essentially all of the available ⁵⁶Mn. The ⁵⁶Mn was standardized using the 4πβ-γ anti-coincidence counting system and confirmed using the CIEMAT/NIST primary method. The resulting bulk material was certified with an uncertainty of 0.8% (k = 2). Minor quantities of ⁶⁵Zn, ^69mZn and ⁴²K were unexpectedly observed but were in minute quantities so as not to affect the results of the standardization or calibration. The standardized ⁵⁶Mn artifact was used to calibrate the Secondary Standard Ionizing Radiation Chamber System (SSIRCS) for a more rapid deployment of the calibrant in the future.

A benchmark for Monte Carlo simulation in gamma-ray spectrometry

Monte Carlo (MC) simulation is widely used in gamma-ray spectrometry, however, its implementation is not always easy and can provide erroneous results. The present action provides a benchmark for several MC software for selected cases. The examples are based on simple geometries, two types of germanium detectors and four kinds of sources, to mimic eight typical measurement conditions. The action outputs (input files and efficiency calculation results, including practical recommendations for new users) are made available on a dedicated webpage.

EGSnrc calculation of activity calibration factors for the Vinten ionization chamber

The National Physical Laboratory Vinten 671 chamber was selected as a proving ground for a new radionuclide source model in the EGSnrc software. The computational Vinten model is validated against measurements of radionuclide artifacts whose activities were determined by absolute methods. The response of the Vinten chamber is first calculated as a function of gamma energy, but more strikingly, an explicit simulation of radionuclide decay was implemented and now permits the direct determination of a calibration factor, including additional effects due to all decay paths of the radionuclide. The Monte Carlo and experimental calibration factors are found to agree at the percent level, in absolute terms.

Evidence against solar influence on nuclear decay constants

The hypothesis that proximity to the Sun causes variation of decay constants at permille level has been tested and disproved. Repeated activity measurements of mono-radionuclide sources were performed over periods from 200 days up to four decades at 14 laboratories across the globe. Residuals from the exponential nuclear decay curves were inspected for annual oscillations. Systematic deviations from a purely exponential decay curve differ from one data set to another and are attributable to instabilities in the instrumentation and measurement conditions. The most stable activity measurements of alpha, beta-minus, electron capture, and beta-plus decaying sources set an upper limit of 0.0006% to 0.008% to the amplitude of annual oscillations in the decay rate. Oscillations in phase with Earth's orbital distance to the Sun could not be observed within a 10^-6 to 10^-5 range of precision. There are also no apparent modulations over periods of weeks or months. Consequently, there is no indication of a natural impediment against sub-permille accuracy in half-life determinations, renormalisation of activity to a distant reference date, application of nuclear dating for archaeology, geo- and cosmochronology, nor in establishing the SI unit becquerel and seeking international equivalence of activity standards.

Renewing the radiopharmaceutical accuracy check service for Canadian radionuclide calibrators

From 1986 to 2000, a fraction of the Canadian nuclear medicine community participated in a service offered by the National Research Council (NRC) of Canada to check the accuracy of administered doses of radiopharmaceuticals. The NRC renewed this service in recent years with a revalidation and reviving of the Secondary Standard Ionizing Radiation Chamber System (SSIRCS). The NRC conducted mock services for (99m)Tc, in varying geometries (syringes and serum vials), on two NRC commercial radionuclide calibrators, and at a nuclear medicine department in Canada. These tests showed the measured doses to be within 10% of the prepared standard but in some cases were sufficiently different from unity to warrant specific geometry factors to be derived.

Reduce, reuse and recycle: a green solution to Canada's medical isotope shortage

Due to the unforeseen maintenance issues at the National Research Universal (NRU) reactor at Chalk River and coincidental shutdowns of other international reactors, a global shortage of medical isotopes (in particular technetium-99m, Tc-99m) occurred in 2009. The operation of these research reactors is expensive, their age creates concerns about their continued maintenance and the process results in a large amount of long-lived nuclear waste, whose storage cost has been subsidized by governments. While the NRU has since revived its operations, it is scheduled to cease isotope production in 2016. The Canadian government created the Non-reactor based medical Isotope Supply Program (NISP) to promote research into alternative methods for producing medical isotopes. The NRC was a member of a collaboration looking into the use of electron linear accelerators (LINAC) to produce molybdenum-99 (Mo-99), the parent isotope of Tc-99m. This paper outlines NRC's involvement in every step of this process, from the production, chemical processing, recycling and preliminary animal studies to demonstrate the equivalence of LINAC Tc-99m with the existing supply. This process stems from reusing an old idea, reduces the nuclear waste to virtually zero and recycles material to create a green solution to Canada's medical isotope shortage.

A comparison of rat SPECT images obtained using (99m)Tc derived from 99Mo produced by an electron accelerator with that from a reactor

Recent shortages of molybdenum-99 ((99)Mo) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce (99)Mo from which technetium-99m ((99m)Tc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced (99m)Tc with those obtained using (99m)Tc from a commercial generator were compared. Disks of (100)Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of (99)Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the (99m)Tc, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using (99m)Tc from a standard reactor (99)Mo generator. The efficiency of (99)Mo-(99m)Tc separation was typically greater than 90%. This study demonstrated the delivery of (99m)Tc from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced (99m)Tc were comparable. High-power electron accelerators are an attractive option for producing (99)Mo on a national scale.

Estrogens and the skin

OBJECTIVE

A review of the medical literature concerning the effect of the menopause and its hormonal treatment on the skin.

METHODS

An extensive Medline and Pubmed internet search utilizing the key words: collagen, elastin, estrogen, hormone replacement therapy, skin and aging.

RESULTS

The literature review demonstrated a wide array of research ranging from basic science work to clinical implications of the effects of the menopause and its treatment on the skin.

CONCLUSION

Estrogen loss at menopause has a profound influence on skin. Estrogen treatment in postmenopausal women has been repeatedly shown to increase collagen content, dermal thickness and elasticity, and data on the effect of estrogen on skin water content are also promising. Further, physiologic studies on estrogen and wound healing suggest that hormone replacement therapy (HRT) may play a beneficial role in cutaneous injury repair. Results on the effect of HRT on other physiologic characteristics of skin, such as elastin content, sebaceous secretions, wrinkling and blood flow, are discordant. Given the responsiveness of skin to estrogen, the effects of HRT on aging skin require further examination, and careful molecular studies will likely clarify estrogen's effects at the cellular level.

Low intervertebral disc height in postmenopausal women with osteoporotic vertebral fractures compared to hormone-treated and untreated postmenopausal women and premenopausal women without fractures

OBJECTIVE

To assess the intervertebral disc height in postmenopausal women with osteoporotic vertebral fractures.

METHODS

A total of 203 women were recruited from a bone densitometer directory. The disc heights measured were those between the 12th thoracic and 3rd lumbar vertebrae. The discs were assigned the symbols D, whereby D(1) refers to the disc between the 12th thoracic and 1st lumbar vertebrae. The disc height of the group of women (n = 38) with osteoporotic vertebral fractures was compared to the disc heights of hormone-treated women (n = 47), untreated postmenopausal women (n = 77) and another group of premenopausal women (n = 41).

RESULTS

The total disc height (D(1) - D(3)) (mean +/- standard deviation) in the fracture group was 1.58 +/- 0.1 cm, significantly lower (p < 0.0001) than in the untreated group (1.82 +/- 0.06 cm), which in turn was significantly (p < 0.0001) lower than in the hormone-treated group (2.15 +/- 0.08 cm) and in the premenopausal group (2.01 +/- 0.09 cm).

CONCLUSION

The fracture group was noted to have the lowest intervertebral disc height compared to the other three groups. The hormone-treated and the premenopausal women had the highest disc heights recorded. These results may be due to the effect that the menopause and senescence have on the discal connective tissue components. This may lead to loss of the shock-absorbing properties of the intervertebral disc and an altered discoid shape, influencing the occurrence of osteoporotic vertebral body fractures.

Granulosa cell production of anti-Müllerian hormone is increased in polycystic ovaries

CONTEXT

There has been renewed interest in anti-Müllerian hormone (AMH) because of its role in the ovary. Data on its actions are sparse, but it appears to inhibit follicle growth. Interestingly, serum AMH is two to three times higher in women with polycystic ovary (PCO) syndrome than women with normal ovaries.

OBJECTIVE

We examined the production of AMH by cells from a range of follicle sizes from normal ovaries and compared this with production by ovulatory and anovulatory (anov) PCOs.

DESIGN

Granulosa cells (GCs) and theca and follicular fluid (ff) were isolated from intact follicles. Cells were cultured for 48 h +/- FSH or LH, and AMH was measured in ff and cell-conditioned media (CM).

RESULTS

AMH levels in ff and GC-CM ranged from 42 to 2240 and 0.025 to 1.7 ng/ml, respectively, and were low or undetectable in ff and GC-CM from follicles greater than 9 mm, luteinized cells, and theca and stroma. The mean level of AMH was four times higher in GC-CM from ovulatory PCOs [mean (range) 1.56 (0.025-7)] and 75 times higher from anovPCO [21.4 (17.2-43 ng/ml)] than normal ovaries [0.37 (0.025-1.7)]. Neither LH nor FSH had an effect on AMH production by GCs from normal ovaries, but in cells from PCOs, FSH significantly decreased AMH, and in contrast, LH increased AMH.

CONCLUSIONS

The reduction of AMH in follicles greater than 9 mm from normal ovaries appears to be an important requirement for the selection of the dominant follicle. AMH production per GC was 75 times higher in anovPCOs, compared with normal ovaries. This increase in AMH may contribute to failure of follicle growth and ovulation seen in polycystic ovary syndrome.

How Low Can You Get?

Since the early 1960s the side effects of oral contraceptives have been known to be related to the high doses (50 micro g) of ethinyl estradiol used. Research has focused on reducing the dose of both the estrogen and progestin components to reduce these side effects. While reducing the dose of both components, the contraceptive efficacy has to be maintained so as to retain a satisfactory Pearl index. These requirements appear to have been attained with 24-day regimen of a low-dose pill (15 microg of ethinyl estradiol and 60 microg of gestedone) as one part of an open-label noncomparative multicenter study. This paper reports our unit's results, which indicate that the low-dose pill promises to reduce contraceptive-related side effects, to encourage better compliance, and as corollary, to retain a satisfactory Pearl index.

Metformin has direct effects on human ovarian steroidogenesis

OBJECTIVE

To investigate the possibility of direct effects of metformin on ovarian steroidogenesis.

DESIGN

Cultured ovarian cells.

SETTING

Academic research environment.

PATIENT(S)

Women undergoing bilateral salpingoophorectomy for benign gynecological disease.

MAIN OUTCOME MEASURE(S)

Estradiol and P were measured in granulosa cell (GC) conditioned medium and androstenedione (A) and P in theca conditioned medium.

RESULT(S)

The effect of addition of metformin alone to GCs was variable, but significant inhibition of both P and E2 was seen (range 0%-30%). Metformin dose-dependently inhibited gonadotrophin and insulin-stimulated P and E2 production (range 25%-50%). In theca, metformin inhibited A production (0%-40%) with no effect on P. In the presence of insulin, A was inhibited dose-dependently and P increased by a similar magnitude.

CONCLUSION(S)

These results demonstrate a direct effect of metformin on ovarian steroidogenesis. The inhibitory effects on androgen production in particular would be beneficial in polycystic ovary syndrome (PCOS).

Insulin-like growth factor (IGF)-independent effects of IGF binding protein-4 on human granulosa cell steroidogenesis

The ovarian insulin-like growth factor (IGF)/IGF binding protein (IGFBP) system operates to permit maximal stimulation of steroidogenesis in the dominant follicle. In atretic follicles, the predominant IGFBPs are IGFBP-2 and IGFBP-4, which appear to be selectively cleaved in healthy follicles. We have recently demonstrated potent inhibition by IGFBP-4 of both theca and granulosa cell steroid production. The degree to which the inhibition occurred suggested that it was greater than might be expected by sequestration of IGF alone. Our study was designed to test this idea. Granulosa cells were harvested from follicles dissected intact from patients undergoing total abdominal hysterectomy and bilateral salpingoophorectomy. Granulosa cells were incubated with or without gonadotropins and IGFBP-4 in the presence or absence of either the IGF type I receptor blocker alphaIR3 or excess IGFBP-3 to remove the effects of endogenous IGF action. Steroid accumulation in the medium was assessed. IGFBP-4 continued to exert potent inhibitory effects when the action of endogenous IGF was removed from the system, demonstrating that its actions are independent of IGF binding. There was no effect on cell metabolism, and the effects on steroidogenesis were reversible after IGFBP-4 removal from the culture medium. No similar effects were seen with IGFBP-2. These reasults are the first evidence of IGF-independent IGFBP-4 actions and the first evidence of IGF-independent actions of any IGFBPs in the ovary.

Increased reduction in bone density and skin thickness in postmenopausal women taking long-term corticosteroid therapy: a suggested role for estrogen add-back therapy

BACKGROUND

Long-term corticosteroid therapy is complicated by osteoporosis and generalized thinning of the skin. These two complications of such therapy were routinely assessed at the Menopause Clinic of St. Luke's Hospital Medical School, University of Malta.

METHODS

A cross-sectional study was performed on 64 postmenopausal women who had been taking long-term corticosteroids. Each woman had her skin thickness measured using high-resolution ultrasound (22 MHz) and her bone density measured by dual-energy X-ray absorptiometry (DEXA). These measurements were compared with those of a control group (n = 557), a group of women who had sustained osteoporotic fractures (n = 180) and a group of women taking hormone replacement therapy (HRT) (n = 399). A longitudinal study of 29 postmenopausal women taking corticosteroids was also performed. This study compared results for women who, in addition to their corticosteroids, were taking HRT and for those who were taking corticosteroids alone.

RESULTS

The cross-sectional study showed that corticosteroid therapy was associated with the lowest mean skin thickness measurement (0.83 mm). Similarly, low mean bone density measurements for the lumbar spine (0.805 g/cm2) and left hip (0.715 g/cm2) were obtained for this group. The mean skin thicknesses in the control group and the HRT group were 0.93 mm and 0.935 mm, respectively, while that in the osteoporotic fracture group was 0.88 mm. The bone density of the fracture group was similar to that of the group of women taking long-term corticosteroids, with the lumbar spine having a mean density of 0.805 g/cm2 and 0.81 g/cm2, and the left hip having a density of 0.705 g/cm2 and 0.715 g/cm2, respectively. Bone densities were similar for the control group and the HRT group, and higher than that of the corticosteroid or fracture group. The lumbar spine had a mean density of 0.925 g/cm2 in the control group and 0.93 g/cm2 in the hormonally treated group. Both the treated and control groups had similar bone densities of the left hip at about 0.82 g/cm2. The small longitudinal study compared postmenopausal women on long-term corticosteroid therapy taking HRT with another group who were not taking HRT. This 4-year study revealed mean total increases in skin thickness of 6.1% and bone density of 5.5% (left hip) and 14.6% (lumbar spine) in the HRT group, since the start of the study. Conversely, the control group registered reductions over 4 years in both skin thickness (2.8%) and bone density (lumbar spine 4.5% and hip 5.0%).

CONCLUSION

In postmenopausal women taking long-term corticosteroids, skin thickness and bone density were both decreased, but the addition of HRT as add-back improved the situation dramatically. Skin thickness and bone density in women taking long-term corticosteroids were comparable to those in women who had sustained osteoporotic fractures. It is therefore suggested that HRT be used as add-back therapy in postmenopausal women taking long-term corticosteroid therapy.

Increased Reduction in Bone Density and Skin Thickness in Postmenopausal Women on Long Term Corticosteroid Therapy

BACKGROUND

Long term steroid therapy is complicated by osteoporosis and generalised thinning of the skin. These two complications of long term corticosteroid therapy were routinely assessed at the Menopause Clinic of St. Luke's Hospital, Medical School, University of Malta.

METHODS

A cross sectional study was performed on 64 postmenopausal women who had been on long term corticosteroids. Each woman had her skin thickness measured using high resolution ultrasound (22 mhz) and their bone density measured using a DEXA Norland. These measurements were compared to a control group (n = 557), a group of women who had sustained osteoporotic fractures (n = 180), and a group of women on hormone replacement therapy (HRT) (n = 399). A longitudinal study on 29 postmenopausal women on corticosteroids was also performed. In this study results were compared between women who in addition to their corticosteroids were on HRT and those who were on corticosteroids alone.

RESULTS

The cross sectional study showed the corticosteroid therapy was associated with the thinnest skin thickness measurements mean 0.83 mm. Similarly, low bone density measurements lumbar spine mean 0.81 g/cm2 and left hip mean 0.71 g/cm2 were obtained for this group. The skin thickness in controls and in the HRT groups had a mean thickness of 0.93 mm while that of the osteoporotic fracture group was 0.88 mm. The bone density of the osteoporotic fractures in the fracture group was similar to that of group of women on long term corticosteroids. The lumbar spine had a mean density of 0.81 g/cm2 and left hip that of 0.71 g/cm2. The bone density of the control group and HRT group was significantly higher. The lumbar spine had a mean density of 0.93 g/cm2 and that of left hip was 0.82 g/cm2. The small longitudinal study compared postmenopausal women on long term corticosteroid therapy on HRT to another group who was not on HRT. The longitudinal study over four years revealed a constant increase in skin thickness (mean 6% per year) and bone density (left hip mean 5% per year, lumbar spine mean 5% per year).

CONCLUSION

In postmenopausal women on long term corticosteroids, skin thickness and bone density were both decreased, but the addition of HRT as add back improved the situation dramatically. Skin thickness and bone density level in women on long term corticosteroids were comparable to that of women who had sustained osteoporotic fractures. It is therefore suggested that HRT be used as add back therapy in postmenopausal women on long term corticosteroid therapy.

Premature response to luteinizing hormone of granulosa cells from anovulatory women with polycystic ovary syndrome: relevance to mechanism of anovulation

Polycystic ovary syndrome is the most common cause of anovulatory infertility. Anovulation in polycystic ovary syndrome is characterized by the failure of selection of a dominant follicle with arrest of follicle development at the 5-10 mm stage. In an attempt to elucidate the mechanism of anovulation associated with this disorder we have investigated at what follicle size human granulosa cells from normal and polycystic ovaries respond to LH. Granulosa cells were isolated from individual follicles from unstimulated human ovaries and cultured in vitro in serum-free medium 199 in the presence of LH or FSH. At the end of a 48-h incubation period, estradiol (E2) and progesterone (P) were determined in the granulosa cell-conditioned medium by RIA. In ovulatory subjects (with either normal ovaries or polycystic ovaries), granulosa cells responded to LH once follicles reached 9.5/10 mm. In contrast, granulosa cells from anovulatory women with polycystic ovaries responded to LH in smaller follicles of 4 mm. Granulosa cells from anovulatory women with polycystic ovaries were significantly more responsive to LH than granulosa cells from ovulatory women with normal ovaries or polycystic ovaries (E2, P < 0.0003; P, P < 0.03). The median (and range) fold increase in estradiol and progesterone production in response to LH in granulosa cell cultures from size-matched follicles 8 mm or smaller were E2, 1.0 (0.5-3.9) and P, 1.0 (0.3-2.5) in ovulatory women and E2, 1.4 (0.7-25.4) and P, 1.3 (0.3-7.0) in anovulatory women. Granulosa cells from anovulatory (but not ovulatory) women with polycystic ovaries prematurely respond to LH; this may be important in the mechanism of anovulation in this common endocrinopathy.

Carotid artery wall changes in estrogen-treated and -untreated postmenopausal women

OBJECTIVE

To investigate whether the thickness of the layers of the carotid artery (externa, media, and intima) are affected by menopause and its treatment with hormone replacement therapy (HRT).

METHODS

One hundred twenty-nine postmenopausal women were recruited sequentially and classified into three groups. Forty-six were taking oral HRT, 32 had estradiol implants, and 51 had never taken HRT. The three layers of the externa wall of the carotid artery were identified and measured by high-resolution ultrasound.

RESULTS

Women with implants had thicker carotid artery wall measurements (0.84 +/- 0.26 mm) than the other groups. The media (0.32 +/- 0.11 mm) was significantly thicker in the implant group. This layer has a high connective tissue component, including collagen type I, collagen type III, and elastin fibers. The intima layer was thinner (0.25 +/- 0.09 mm) in the oral HRT group compared with controls (0.29 +/- 0.1 mm). A statistically significant higher intima-media ratio (1.17 +/- 0.05) was calculated for the control group, compared with both the oral HRT (0.92 +/- 0.04) and implant groups (0.94 +/- 0.03).

CONCLUSION

Our findings suggest that HRT given to postmenopausal women influences differentially the layers of the carotid artery. Hormones seem to encourage thickening of the layers with the highest connective tissue component (externa and media) and to delay thickening of the atheromatous intima layer. These effects on the vascular system may be partly responsible for the cardioprotection attributed to HRT.

Changes in bone collagen markers and in bone density in hormone treated and untreated postmenopausal women

OBJECTIVE

This study aims to compare bone mineral density measurements (BMD), pyridinium crosslink levels and pyridinium crosslink levels in untreated and hormone treated postmenopausal women.

METHODS

A cross-sectional study comparing biophysical (BMD) and biochemical (pyridinium crosslink and PCICP) parameters in a group of untreated postmenopausal women (n = 145) to a group of postmenopausal women on hormone replacement therapy (HRT) (n = 92).

RESULTS

Untreated postmenopausal women compared to postmenopausal women on HRT had higher Osteoblastic and Osteoclastic activity. Procollagen I C-end terminal peptide (PCICP) was 11.3% lower in the women on HRT compared to controls whilst crosslinks were 27.2% lower than in controls. This seems to indicate that women on HRT had a bone balance that was higher compared to the control group (15.9%). The difference in bone density of L2-L4 between the two groups was (16.1%).

CONCLUSIONS

This study seems to indicate that postmenopausal women receiving HRT readjust their bone remodelling so that although osteoblastic function is reduced, there is a much greater deduction in osteoclastic function and this results in an overall higher bone mass observed in the BMD of women on HRT.

Carotid artery wall thickness in women treated with hormone replacement therapy

OBJECTIVE

To measure the thickness of the individual layers (externa, media, intima) of the carotid artery in two groups of postmenopausal women.

METHODS

A high resolution ultrasound (25-MHz Osteoson DIII Minhorst) was used to assess the distal end of the common carotid artery. Forty-six women were on hormone replacement therapy (Premarin 0.625 mg and Norgestrel 1 mg) for more than 1 year. The measurements of the treated group were compared to those of 51 postmenopausal women who acted as controls.

RESULTS

No significant difference between the externa and media layers of both groups of women were noted. The media showed a tendency to be thicker in the treated group. The intima of the untreated group was found to be significantly thicker than that of the treated group (P < 0.05). Significant correlations were found between the layers of the carotid artery especially between the externa and media both mainly composed of connective tissue (Collagen Type I and III and elastin). The media/intima ratio of the treated women was significantly higher than that of the untreated group (P< 0.003).

CONCLUSION

It is postulated that the changes observed may be due to the effect of oestrogen on connective tissue. These arterial changes induced by hormone replacement therapy may partially explain the cardioprotective effect this treatment has on postmenopausal women. The increased intimal thickness in untreated women compared to treated ones on the other hand would represent the reduction in atheromatous plaque formation in women on oestrogen replacement therapy.

The epidemiology of osteoporotic fractures in a Mediterranean country

A population study was carried out over a period of 3 years (1987-1989) to determine the incidence of osteoporotic fractures. Fractures diagnosed in the two acute hospitals of the Maltese Islands were collected and classified according to the fracture site, age, sex, and patient's residence. Fractures in the Maltese Islands can only be diagnosed and adequately treated in these two general hospitals. A total of 8780 fractures were examined. Fracture of the neck of the femur was the most common fracture for which patients were admitted to the hospital. There were twice (1.96) as many females as males hospitalized for this fracture, giving an annual incidence of 262/100,000 females to 134/100,000 males over the age of 45. The fracture incidence was 2-3 times less than that found in North European countries, but was similar to the fracture rates obtained in Mediterranean studies. Fracture radius was the most frequent fracture treated on an outpatients basis. In over 45-year-olds, the female predominance persisted, giving a ratio of 3.65:1. This gave an annual incidence of 452/100,000 females to 150/100,000 males. Again, the fracture incidence obtained was significantly lower than that of Northern European countries. Other long bones showed a similar female to male (F:M) ratio in the cohort over 45 years of age. The bones showing this F:M ratio were the humerus (3.9:1), fibula (1.89:1), and tibia (1.6:1). Below 45 years of age males had more fractures than females for any bone studied.(ABSTRACT TRUNCATED AT 250 WORDS)

A long-term clinical trial with a non-steroidal oestrogen

A double-blind clinical trial has been carried out with a new non-steroidal oestrogenic substance (P1496). Taken cyclically over a period of 15 months or more the drug appears to be well tolerated and apparently free of toxic effects. In the dosage used the drug is clinically effective as an oestrogen analogue.

An ergocryptine as a lactation inhibitor

A double-blind trial was performed on 40 parturient women to compare the efficacy of an ergocryptine (CB 154) as a lactation inhibitor in comparision with chlorotrianisine (TACE). The two drugs were about equally effective. The drug CB 154 is unlikely to be associated with puerperal thrombo-embolism, it does not seem to be followed by rebound lactation, and it may prove particularly effective in women with a previous history of puerperal mastitis or breast engorgement.