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Biomedical subjects

A Prentice

Publications and source records attributed to A Prentice.

At least 55 records · Page 3Linked to original sources
PubMed1998

Biochemical markers of calcium and bone metabolism during 18 months of lactation in Gambian women accustomed to a low calcium intake and in those consuming a calcium supplement.

The effect of 18 months of lactation on indexes of calcium and bone metabolism was studied in 60 Gambian women accustomed to a very low calcium intake. Half the women consumed a calcium supplement from 10 days postpartum for 52 weeks (supplement, 714 mg Ca/day; total Ca intake, 992 +/- 114 mg/day), and half consumed placebo (total Ca intake, 288 +/- 128 mg/day). Fasting blood and 24-h urine samples were collected at 1.5, 13, 52, and 78 weeks of lactation and analyzed for calciotropic hormones (intact PTH, 1,25-dihydroxyvitamin D, and calcitonin), bone turnover markers (osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline), and plasma minerals (calcium and phosphate). The first months of lactation were associated with increased bone turnover and plasma phosphate, and decreased PTH and 1,25-dihydroxyvitamin D. These effects diminished by 52 weeks, although breast milk volumes remained high. The Gambians had higher PTH, 1,25-dihydroxyvitamin D, and bone formation than British women with a greater customary calcium intake. None of the biochemical indexes was affected by calcium supplementation, with the possible exception of bone alkaline phosphatase (-29% at 52 weeks; P = 0.015). These data demonstrate that lactation-associated changes in calcium and bone metabolism are physiological and are independent of dietary calcium supply in women with very low calcium intakes.

Adolescent↗
PubMed1998

Zinc and phytate intake of rural Gambian infants: contributions from breastmilk and weaning foods.

Zinc and phytate intakes of 183 rural Gambian infants were obtained from weighed records of breastmilk and food intake and measured contents in foods. Total zinc intake of 2.7 mg/d in the first month of age declined to 1.5 mg/d at 3 months, then increased to 4.3 mg/d by 17 months. Breastmilk was an important source of zinc, but the predominant cereal and groundnut-based foods had high [phytate]/[Zn] molar ratios ranging from 13 to 28, indicating potential impaired zinc bioavailability. The [phytate]/[Zn] molar ratio for the diet as a whole was low in early infancy, but increased to 13 in the second year. In contrast, this ratio was less than 6 for the diet of 48 Cambridge breastfed infants up to 18 months. A further disadvantage to the Gambian infants was indicated by their lower intake of protein of animal origin. However, calcium intake was estimated in both communities to be below the level which could give rise to zinc chelation in association with phytate. Compared to 'basal' and 'normative' requirements, total zinc intake of the Gambian infants showed the greatest shortfall between 3 and 12 months, making this the age band for maximum probable benefit from focused intervention programmes.

Child, Preschool↗
PubMed1998

Evaluation of facilitated communication.

Two case studies are presented to demonstrate the effectiveness of Facilitated Communication (FC). A wide variety of sources of data have been examined and consistent behaviour found within FC interactions. There are indications that changes in behaviour of both people resulted at least in part from the use of FC.

Adult↗
PubMed1997

Plasma total homocysteine in a representative sample of 972 British men and women aged 65 and over.

OBJECTIVES: To provide a reference range for plasma total homocysteine (tHcy), an independent risk factor for vascular disease, and to explore relationships with nutritional indices for people aged 65 y and over, in the UK National Diet and Nutrition Survey (NDNS). DESIGN: The survey procedures described in the National Diet and Nutrition Survey Report (1997) included a health-and-lifestyle interview, a four-day weighed diet record, anthropometric and blood pressure measurements and a fasting blood sample for biochemical indices, including tHcy. SETTING: Eighty randomly selected postcode sectors from mainland Britain during 1995-1996. SUBJECTS: Of 2060 people interviewed, 1527 were visited by the nurse, 1276 gave a blood sample and 972 had tHcy measured. About 80% were in their own homes and the remainder were in nursing homes or similar institutions. RESULTS: Significant cross-sectional relationships, both univariate and multivariate were found between tHcy and index concentrations of folate and vitamin B12 (P < 0.0001), and between tHcy and plasma creatinine, urea, calcium, zinc, alpha 1-antichymotrypsin, lutein and cysteine (P = 0.013 to < 0.0001). Dietary nutrient analyses showed an association with folate intake. tHcy was also correlated with age and with domicile (free-living or institution), with history of vascular disease and with use of four classes of drugs, two of which are prescribed for vascular diseases. There was a north-south gradient in tHcy (P = 0.005), and also in food choices, blood micronutrient indices and vascular disease prevalence. CONCLUSIONS: The concentrations of tHcy found in this study provide a reference range for people aged 65 y and over, in mainland Britain. tHcy is a valuable functional index of micronutrient status and intakes for British people aged 65 y and over, which can assist the development of health-promotion strategies.

Aged↗
PubMed1997

Immunolocalization of the apoptosis regulating proteins Bcl-2 and Bax in human endometrium and isolated peritoneal fluid macrophages in endometriosis.

Endometriosis, a debilitating disease associated with infertility, is characterized by the prolonged presence of ectopic endometrial tissue and the involvement of activated peritoneal fluid macrophages. Apoptosis, which occurs in both endometrium and peritoneal fluid macrophages, is controlled in part by members of the Bcl-2/Bax family of proteins. Here, through immunohistochemical staining, we investigated the Bcl-2/Bax status in endometrium and peritoneal fluid macrophages in endometriosis. Bcl-2/Bax immunoreactivity was found predominantly in the glandular epithelial cells, mainly during the proliferative phase of the menstrual cycle for Bcl-2 but throughout the entire menstrual cycle for Bax. Ectopic endometrium contained a population of Bcl-2 positive. Bax negative tissue macrophages. Fluorescence-activated cell sorting of isolated peritoneal fluid macrophages showed that women with endometriosis had a significantly higher proportion of Bcl-2 positive macrophages than the non-endometriotic group. The proportion of Bax positive peritoneal fluid macrophages was significantly elevated in women without endometriosis. The increased proportion of Bcl-2 positive macrophages found in women with endometriosis may predispose these cells to resist apoptosis. The continued survival of these active cells could have important consequences for the survival and proliferation of the ectopic endometrial tissue.

Adult↗
PubMed1997

Decreased levels of the potent regulator of monocyte/macrophage activation, interleukin-13, in the peritoneal fluid of patients with endometriosis.

Endometriosis is characterized by an increase in the number, activation and secretory activity of peritoneal fluid macrophages. Factors regulating the activation of these cells may be important in the pathophysiology of this disease. In this study we measured by enzyme-linked immunosorbent assay the concentrations of the macrophage inhibitory factor interleukin (IL)-13 in the peritoneal fluid of women with and without endometriosis. It was found that women with endometriosis had significantly lower amounts of IL-13 (95 +/- 9.8 pg/ml) in peritoneal fluid, compared with women without endometriosis (115 +/- 30 pg/ml) (P < 0.01). No cycle-specific variation was evident for either group. Another macrophage inhibitory interleukin (IL-10) was also measured, but no differences between women with (16.1 +/- 13.2 pg/ml) or without (10.3 +/- 5.6 pg/ml) endometriosis were seen. The immunolocalization of IL-13 was assessed in eutopic and ectopic endometrium and in isolated peritoneal fluid cells. Glandular epithelial cells and stromal cells in both eutopic and ectopic endometrium were immunopositive for IL-13. No cycle-specific differences in the immunolocalization of IL-13 were seen. In conclusion, the reduced amounts of IL-13 in the peritoneal fluid of women with endometriosis may lead to a lack of suppression of macrophage activation, thereby contributing to the overall pathogenesis of this disease.

Adult↗
PubMed1997

Single versus double insemination: a retrospective audit of pregnancy rates with two treatment protocols in donor insemination.

Our objective was to evaluate the effect of a change in treatment protocols, suggested following an inspection visit by the regulatory authority, from single to double inseminations during donor insemination treatment cycles. We therefore conducted a retrospective audit of pregnancy rates in the reproductive medicine clinic of a major teaching hospital. All patients were treated for male factor infertility by donor insemination, without ovulation induction with gonadotrophins between October 1992 and December 1995. The main outcome measures were cumulative conception and live birth rates. During the study period 250 patients underwent treatment and 650 single insemination and 277 double insemination treatment cycles were undertaken. The pregnancy rate per cycle was 0.054 and 0.119 for single and double insemination respectively. After six cycles the cumulative pregnancy rates were 0.28 and 0.47 and the take-home baby rates were 0.25 and 0.37 for single and double inseminations respectively. The change in practice from single to double insemination resulted in a doubling of the pregnancy rate per treatment cycle. Cumulative pregnancy rates after two treatment cycles of double insemination were comparable with those achieved after six cycles of single insemination. These results have significant implications for both patients and purchasers.

Female↗
PubMed1997

The management of cervical carcinoma within the south west region of England. Expert Tumour Panel.

OBJECTIVE: 1. To audit the management of cervical carcinoma in the South West Region with the aim of identifying and addressing deficiencies. 2. To determine whether recent NHS restructuring has affected the provision of cancer care. DESIGN: Retrospective review of hospital case notes. SETTING: All hospitals in the South West Region of England. POPULATION: Three hundred and twenty-four women with a diagnosis of cervical carcinoma: 191 were diagnosed in 1989 and 133 in 1993. MAIN OUTCOME MEASURES: Documentation of patient assessment and management. RESULTS: There was a mean delay of 17 days (range 0-66) from cervical smear to cytology report and 34 days (range 1-380) from general practitioner referral to attendance at a hospital clinic. Overall, 175 women (54%) had evidence of cytological assessment prior to treatment and 137 (42%) had a colposcopic assessment; 49% had cytological assessment and 37% had colposcopy in 1989, compared with 60% and 50%, respectively, in 1993. Excluding 49 cases of micro-invasive carcinoma, 238 case notes (86%) contained evidence of clinical examination; 195 women (71%) had had an examination under anaesthesia, 115 (42%) a chest radiograph, 123 (45%) an intravenous urogram or renal ultrasound, and 92 (33%) cystoscopy. One hundred and forty-seven women (53%) had FIGO staging recorded in the notes. As first line treatment, 69 had conservative surgery (39 for Stage IA), 138 had radiotherapy, and 107 had radical surgery. Ten had radical surgery for Stage IA but eight had a > 3 mm invasion or lymphatic/vascular spread. Thirty-one had Stage IB treated with radiotherapy of whom 14 were younger than 50 years of age. Following radical surgery 30% had evidence of sampling > or = 10 nodes, and 9% had tumour extending to the resection margins. CONCLUSIONS: Record keeping was inadequate but appeared to indicate inconsistent cytological, clinical, colposcopic and radiological assessment, leading to inappropriate clinical delays and conservative surgery. Radical surgery often appeared inadequate, but poor node sampling rates may also reflect insufficient histopathological preparation or reporting. There was a reduction in the number of new cases of cervical carcinoma diagnosed in 1993, perhaps reflecting an observed increase in cytological surveillance. No other alterations in clinical practice were observed over the four-year period. We feel it is imperative to standardise assessment throughout the region with a minimum clinical and histopathological dataset.

Adult↗
PubMed1997

Vitamin D status does not influence the breast-milk calcium concentration of lactating mothers accustomed to a low calcium intake.

Plasma 25-hydroxy-vitamin D and breast-milk calcium concentration were measured at 3 months of lactation in 60 Gambian mothers accustomed to a low calcium diet, of whom 30 were consuming a calcium supplement and 30 were receiving a placebo, and in 48 British mothers. The plasma 25-hydroxy-vitamin D concentration of the Gambian women was not affected by either calcium supplementation (supplemented, 64.4 +/- 2.5 nmol l(-1); placebo, 64.9 +/- 3.5 nmol l(-1); mean +/- SE) or season. The British average was lower (53.9 +/- 3.0 nmol l(-1), p = 0.004), owing to marked seasonal effects. The breast-milk calcium concentration was lower in The Gambia (supplemented, 5.38 +/- 0.13 mmol l(-1); placebo, 5.10 +/- 0.13 mmol l(-1); British, 6.93 +/- 0.15 mmol l(-1), p < 0.0001). There was no relationship between plasma 25-hydroxy-vitamin D and breast-milk calcium concentration in any group. There was no trend towards lower breast-milk calcium concentration in women with vitamin D status towards the bottom of the normal range or in British women during the winter. This study provides no support for the hypothesis that breast-milk calcium concentration is influenced by vitamin D status or that lactating women with a low calcium intake are at particular risk of vitamin D deficiency.

Adolescent↗
PubMed1997

Whole body bone mineral content in healthy children and adolescents.

Data from healthy children are needed to evaluate bone mineralisation during childhood. Whole body bone mineral content (BMC) and bone area were examined by dual energy x ray absorptiometry (Hologic 1000/W) in healthy girls (n = 201) and boys (n = 142) aged 5-19 years. Centile curves for bone area for age, BMC for age, bone area for height, and BMC for bone area were constructed using the LMS method. Bone mineral density calculated as BMC/bone area is not useful in children as it is significantly influenced by bone size. Instead, it is proposed that bone mineralisation is assessed in three steps: height for age, bone area for height, and BMC for bone area. These three steps correspond to three different causes of reduced bone mass: short bones, narrow bones, and light bones.

Adolescent↗
PubMed1996

Vascular endothelial growth factor is produced by peritoneal fluid macrophages in endometriosis and is regulated by ovarian steroids.

Angiogenesis is important in the pathophysiology of endometriosis, a condition characterized by implantation of ectopic endometrium in the peritoneal cavity. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor involved in physiological and pathological angiogenesis, and elevated levels of VEGF are found in peritoneal fluid of patients with endometriosis. Our aim was to investigate the site of expression and regulation of VEGF in endometriosis. VEGF immunoreactivity was found in tissue macrophages present in ectopic endometrium and in activated peritoneal fluid macrophages. Macrophage activation was highest in women with endometriosis, and media conditioned by peritoneal fluid macrophages from these women caused a VEGF-dependent increase in endothelial cell proliferation above that seen from normal women. Peritoneal fluid macrophages secreted VEGF in response to ovarian steroids, and this secretion was enhanced after activation with lipopolysaccharide. Peritoneal fluid macrophages expressed receptors for steroid hormones. VEGF receptors flt and KDR (kinase domain receptor) were also detected, suggesting autocrine regulation. During the menstrual cycle, expression of flt was constant but that of KDR was increased in the luteal phase, at which time the cells migrated in response to VEGF. KDR expression and the migratory response were significantly higher in patients with endometriosis. This study demonstrates that activated macrophages are a major source of VEGF in endometriosis and that this expression is regulated directly by ovarian steroids.

Adult↗
PubMed1996

Bone mineral mass consolidation in young British adults.

Forty males and 40 females, ages 18-21 years, were recruited into a prospective study to investigate the consolidation of bone mineral after cessation of linear growth and the influences of calcium intake, lifestyle factors, physical activity, and body composition on bone. Three sets of bone measurements were made annually at the spine, hip, and whole body (dual-energy X-ray absorptiometry) and at the wrist and midshaft radius (single photon absorptiometry). At baseline, the bone mineral content (BMC) was significantly greater in males than females at all sites (p < 0.004). After adjustment for scan area (BA), height, weight, and age, male BMC was significantly greater than female BMC at the midshaft radius (+7.4%; p < 0.01) but lower at the spine (-10.9%; p < 0.001) with no difference at the wrist, hip, or whole body. Positive effects of leanness on bone were observed in females but not in males. Dietary calcium, nutrient intakes, and physical activity levels were not size-independent determinants of BMC at any site. Significant increases in whole-body BMC were observed within individuals over the study period of 670 (SD 51) days, +1.3% in males and +2.1% in females (p < 0.01), mirrored by increases in BMC and BA at most skeletal sites. After allowing for changes in BA, significant increases (p < 0.01) were observed in adjusted BMC for the whole body (males, +1.1%; females, +0.6%), lumbar spine (males, +1.5%; females, +1.1%), and midshaft radius (males, +1.9%; females, +2.0%). No lifestyle or anthropometric factors were identified that influenced these longitudinal increases in bone mineral.

Adolescent↗
PubMed1996

Low bone mineral content is common but osteoporotic fractures are rare in elderly rural Gambian women.

Osteoporosis is reported to be rare in Black Africa. The low fracture incidence among North American black women is explained by a high peak bone mass and preservation of bone mineral into old age. To assess whether this is the case among Black African women, we measured bone mineral content (BMC) and bone mineral density (BMD), using single- and dual-photon absorptiometry, in 195 rural Gambian women aged over 44 years and 391 white women of comparable age from three centers in the U.K. Measurements were made at the midshaft of the radius, distal radius, lumbar spine, and femoral neck. The influence of height, weight, and nationality on BMC and BMD was analyzed. BMC and BMD decreased with age at all sites. Age, decreasing weight, but not height were independently associated with lower BMC at all sites. BMC in Gambian women was lower than in British women by 31% at the lumbar spine and 16% at the midshaft of the radius. After adjustment for age, height, and weight, BMC among Gambian women remained 24% lower at the lumbar spine and 10% lower at the radius. In women aged over 64 years, BMC at the lumbar spine was 42% lower and BMD was 31% lower in The Gambia (for all comparisons, p < 0.005). We conclude that bone mineral mass is not preserved in elderly Gambian women. However, minimal trauma fractures are rare in this population. These results challenge the concept of BMC as a primary determinant of fracture risk.

Adult↗