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Biomedical subjects

M Brincat

Publications and source records attributed to M Brincat.

At least 19 recordsLinked to original sources
PubMed2006

Endodontics and infective endocarditis--is antimicrobial chemoprophylaxis required?

The purpose of this review is to evaluate the evidence implicating nonsurgical endodontic procedures in inducing infective endocarditis (IE). The literature is reviewed and findings about dental procedures that elicit bacteraemia [in particular root canal treatment (RCT)], sequelae of bacteraemia, relationship between IE and RCT and variation between antibiotic prophylaxis (AP) guidelines are highlighted. At present, there is still significant debate as to which dental procedures require chemoprophylaxis and what antibiotic regimen should be prescribed. Currently, there are insufficient primary data to know whether AP is effective or ineffective against IE. Practitioners are bound by current guidelines and medico-legal considerations. Thus, the profession requires clear, uniform guidelines that are evidence-based.

Amoxicillin↗
PubMed2005

TNFRSF11B gene variants and bone mineral density in postmenopausal women in Malta.

UNLABELLED: A number of polymorphisms in various genes have been identified and associated with bone mineral density (BMD) and with an increased risk of osteoporosis. OBJECTIVE: In this study, three single nucleotide polymorphisms (SNPs) within the TNFRSF11B gene were studied for association with an increased risk of osteoporosis in postmenopausal Maltese women (n=126). METHODOLOGY: Analysis was performed by PCR restriction fragment length polymorphism (RFLP) while BMD at the lumbar spine, femoral neck, Ward's triangle and trochanter was measured by DEXA. RESULTS: No significant association was observed between genotypes and BMD for all polymorphisms studied within this gene. Homozygotes CC (T(950)-C) were observed to have the highest BMD at all anatomical sites although statistical significance was not reached when comparing the three genotypes. A statistical significant difference was observed in the distribution of genotype frequencies for this polymorphism between normal individuals and those that were either osteopenic or osteoporotic at one or both anatomical sites, with the TT genotype associated more frequently with low BMD. The T(950)-C and G(1181)-C polymorphisms were in strong linkage disequilibrium with each other but not with the A(163)-G polymorphism further upstream in the OPG promoter. Statistical significance was reached when constructing haplotypes, where the A-T-G haplotype was found to be more frequent in individuals with low BMD. CONCLUSIONS: These results indicate the possible role of TNFRSF11B gene variants in postmenopausal bone loss in women in Malta.

Absorptiometry, Photon↗
PubMed2004

Hormone replacement in women with breast cancer: the HABITS study.

Ever since Professor William T. Creasman suggested the use of hormone replacement therapy in breast cancer survivors in the early 1980s, interest in this field has been guarded but present. Prescribing HRT to breast cancer survivors was initially thought of as being outrageous. Yet even then with experience in HRT spanning a good three decades, and with the breast cancer epidemic, so confidently predicted, then as it is now never actually materializing, doctors working in the field had started to question the conventional wisdom. The debate on whether to treat breast cancer survivors with HRT has been revisited from time to time as there has been a powerful demand for a solution for such symptomatic women. The HABITS study was thus designed to investigate the use of HRT in breast cancer survivors.

Breast Neoplasms↗
PubMed2003

Associations of polymorphisms in the vitamin D receptor gene (BsmI and FokI) with bone mineral density in postmenopausal women in Malta.

Previous studies have suggested that variations in the vitamin D receptor (VDR) gene are related to bone mineral density (BMD). In this study, the T-->C transition in the start codon and the G-->A polymorphism at the 3' end of the VDR gene, identified by endonucleases FokI and BsmI, respectively, were analysed and correlated with BMD in postmenopausal Maltese women ( n=104). Genotype frequencies observed for the VDR start codon polymorphism (SCP) were CC: 60.4%; CT: 30.7% and TT: 8.9%, while those observed for the 3' in this study were GG: 16.4%; GA: 51.9%; AA: 31.7%. In postmenopausal women, both lumbar and femoral BMD were observed to be highest in CC homozygotes for the FokI genotype and in GG homozygotes for the BsmI genotype, although in both groups the difference between the genotypes was not statistically significant, even after adjusting BMD for age, BMI and years since menopause. No evidence of linkage disequilibrium between the two alleles was observed.

Adult↗
PubMed2003

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.

Adult↗
PubMed2002

The reproducibility of endometrial volume acquisition and measurement with the VOCAL-imaging program.

OBJECTIVES: To determine the intraobserver reproducibility of volume acquisition and repeatability of endometrial volume measurements using the VOCAL-imaging program (Virtual Organ Computer-aided AnaLysis). METHODS: Ten three-dimensional (3D) ultrasound datasets of the same endometrium were obtained from one patient during one scan session. For every 3D dataset, the endometrial volume was calculated by four different measurement techniques; three rotational methods and one conventional method. A single observer acquired each dataset and conducted all measurements. For the rotational technique, the manual mode was used to trace the myometrial-endometrial border through three different predefined rotations of 30 degrees, 15 degrees and 9 degrees . Endometrial volume was also measured in a conventional manner by scrolling through one of the multiplanar images and outlining the contour in another. Ten consecutive measurements were taken for each of the four measurement techniques so that 40 endometrial volume readings were obtained for each of the 10 3D-ultrasound datasets. RESULTS: Endometrial volume measurements were more reproducible with the rotational technique. Rotational methods employing a rotation step of less than 30 degrees were associated with coefficients of variation below 1% and intraclass correlation coefficients above 0.94. Within each of the 10 different scans, the homogeneity of the variance of measurements was significantly different according to the method of measurement (P = 0.022 to < 0.001). Post-hoc tests revealed that both the conventional and 30 degrees rotational methods resulted in a significantly smaller mean endometrial volume than both the 15 degrees and the 9 degrees rotational methods. CONCLUSIONS: Endometrial volume acquisition is reproducible and endometrial volume measurements are repeatable but they depend upon the technique of volume calculation in so much as rotational methods employing a rotation step of less than 30 degrees are associated with a significantly smaller variance in measurements and a significantly greater mean endometrial volume.

Adult↗
PubMed2001

Urogenital prolapse and atrophy at menopause: a prevalence study.

For 285 subjects referred to a menopause clinic data were prospectively collected on the time elapsed since the onset of menopause (menopausal age), sexual activity, dyspareunia, smoking, chronic cough and constipation. Prolapse and atrophy were sought on examination. FSH assay confirmed menopausal status. We found an anterior wall prolapse in 51% of the subjects, of which 6% were protruding beyond the introitus. Posterior wall prolapse was present in 27% and apical prolapse in 20%; none was protruding beyond the introitus. No trend was noted between prolapse and menopausal age. Atrophy was evident in 34% of the women, and this was related to menopausal age (P<0.001). Forty per cent of the sexually active women admitted to dyspareunia, of which 2/3 were superficial. This correlated with advancing menopausal age (P<0.02). In conclusion, genital prolapse was frequent in the population of postmenopausal women, predominantly cystocele, but the prevalence did not correlate with menopausal age.

Adult↗
PubMed1999

Increased reduction in bone density and skin thickness in postmenopausal women on long-term corticosteroid therapy. A suggested role for estrogen add back 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.

Adrenal Cortex Hormones↗
PubMed1998

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.

Arteriosclerosis↗
PubMed1998

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.

Adult↗
PubMed1997

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.

Adult↗
PubMed1997

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.

Aged↗
PubMed1994

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)

Adolescent↗
PubMed1993

A clinical trial on the effects of a combination of elcatonin (carbocalcitonin) and conjugated estrogens on vertebral bone mass in early postmenopausal women.

The study was carried out to determine the effect of a combination regimen of a small dose of calcitonin added to conjugated estrogens with medroxyprogesterone acetate on vertebral bone mass in early postmenopausal women. Comparisons were made with groups of women on calcitonin alone, on conjugated estrogens with medroxyprogesterone acetate alone, or on no treatment. The study was carried out over a 2-year period. The results of the study suggest that the combined regimen of calcitonin and estrogens increased vertebral bone mass in early postmenopausal women to a greater extent than calcitonin alone or estrogen alone. Increases in vertebral bone mass of 11.2% after 1 year and 9.2% after 2 years were demonstrated using the combined regimen. Both estrogens alone and calcitonin alone were, however, very effective in preventing rapid bone loss in the postmenopausal women studied.

Administration, Oral↗
PubMed1992

Effect of hormone replacement therapy and calcitonin on bone mass in postmenopausal women.

A total of 104 postmenopausal women were randomly assigned to different therapeutic regimens: (a) calcitonin, (b) estrogen/progestogen (HRT) plus calcitonin, (c) estrogen/progestogen (HRT), (d) and the control group. The bone mass of the lumbar vertebrae of all patients was assessed with a dual beam photon absorptiometer (Norland GD 153). The 73 patients who completed the 1-yr study showed that postmenopausal bone loss could be prevented by either estrogen/progestogen (HRT) or calcitonin. In addition, the combination of hormonal replacement therapy and calcitonin not only prevented post-menopausal bone loss but resulted in a significant 10% gain in bone mass (P < 0.001).

Absorptiometry, Photon↗
PubMed1992

Effect of 17 beta-oestradiol on lymphocyte subpopulations, delayed cutaneous hypersensitivity responses and mixed lymphocyte reactions in post-menopausal women.

High-dose steroids are known to be potent modulators of the immune response. We accordingly investigated the effect of therapeutic doses of 17 beta-oestradiol (E2) on cellular immune responses in post-menopausal women. Fifteen (15) healthy women who had undergone a natural menopause were treated with E2 in the form of 100 mg estraderm patches applied twice weekly for 3 out of every 4 weeks over a 3-month period, followed by combined oestrogen and progestogen formulations as long-term therapy. Blood samples were taken on two occasions prior to treatment and at weeks 1, 3, 4, 7, 9, 12 and 24 after commencing therapy. Lymphocyte subsets (CD2, CD4, CD8, CD19, HLA-DR and NK) were studied in each blood sample using a monoclonal antibody kit and a two-colour fluorescence flow-cytometer. One-way mixed lymphocyte reactions (MLRs) were performed using the same stimulator throughout. Delayed hypersensitivity skin tests (DHTs) were carried out twice before treatment and at weeks 3, 4, 12 and 24 using Multitest 7-antigen kits (Institut Mérieux). Lymphocyte subsets did not change significantly with treatment, but both the MLRs and the DHTs were significantly depressed, maximally so by the third week of treatment. We conclude that therapeutic doses of E2 modulate certain immune responses. The significance of this is discussed in the light of the increasing use of long-term oestrogen replacement therapy.

Estradiol↗