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Biomedical subjects

D Howarth

Publications and source records attributed to D Howarth.

At least 19 recordsLinked to original sources
PubMed2005

Complementary role of adjunctive breast magnetic resonance imaging and scintimammography in patients of all ages undergoing breast cancer surgery.

The aims of this study were to assess breast MRI and scintimammography (SMM) for the detection of breast cancer, and to determine any complementary role of these tests to each other and conventional imaging. Seventy-two patients (age 35-81 years) with a suspicious breast mass were investigated by mammography, breast ultrasound, breast MRI and SMM before undergoing surgical excision of the breast mass. Sensitivity, specificity and area under receiver operator characteristic curves were calculated for each test. Of the 72 patients, there were 66 proven malignant tumours, including two patients with bilateral breast cancer. When comparing the diagnostic sensitivity of breast MRI and SMM for lesion size, both tests showed higher sensitivities for lesions >25 mm in size, particularly for SMM. When these tests were compared for patient age, patients less than 51 years showed higher sensitivities for both tests. This was statistically significant for breast MRI. The overall respective diagnostic sensitivities for mammography, mammography with breast ultrasound, breast MRI and SMM were 56, 67, 86 and 85%. The differences were significant between mammography, mammography/ultrasound and both breast MRI and SMM. Breast MRI and SMM offer incremental diagnostic advantage in the diagnosis of breast cancer. Although improved diagnostic accuracy is seen in patients of all ages, those patients less than 51 years of age receive the greatest diagnostic benefit.

Adult↗
PubMed2002

A performance evaluation of commercial fibrinogen reference preparations and assays for Clauss and PT-derived fibrinogen.

The wide availability of fibrinogen estimations based on the prothrombin time (PT-Fg) has caused concern about the variability and clinical utility of fibrinogen assays. In a multi-centre study, we investigated fibrinogen assays using various reagents and analysers. Clauss assays generally gave good agreement, although one reagent gave 15-30% higher values in DIC and thrombolysis. Two commercial reference preparations had much lower potencies than the manufacturers declared, and plasma turbidity influenced parallelism in some Clauss assays. PT-Fg assays gave higher values than Clauss and showed calibrant dependent effects, the degree of disparity correlating with calibrant and test sample turbidity. Analyser and thromboplastin dependent differences were noted. The relationship between Clauss and PT-Fg assays was sigmoid, and the plateau of maximal PT-Fg differed by about 2 g/l between reagents. ELISA and immunonephelometric assays correlated well, but with a high degree of scatter. Antigen levels were higher than Clauss, but slightly lower than PT-Fg assays, which appeared to be influenced by degraded fibrinogen. Clauss assays are generally reproducible between centres, analysers and reagents, but PT-Fg assays are not reliable in clinical settings.

Blood Coagulation Tests↗
PubMed2001

Determination of the optimal minimum radioiodine dose in patients with Graves' disease: a clinical outcome study.

The study was performed under the auspices of the International Atomic Energy Commission, Vienna, Austria, with the aim of determining the optimal minimum therapeutic dose of iodine-131 for Graves' disease. The study was designed as a single-blinded randomised prospective outcome trial. Fifty-eight patients were enrolled, consisting of 50 females and 8 males aged from 17 to 75 years. Each patient was investigated by clinical assessment, biochemical and immunological assessment, thyroid ultrasound, technetium-99m thyroid scintigraphy and 24-h thyroid 131I uptake. Patients were then randomised into two treatment groups, one receiving 60 Gy and the other receiving 90 Gy thyroid tissue absorbed dose of radioiodine. The end-point markers were clinical and biochemical response to treatment. The median follow-up period was 37.5 months (range, 24-48 months). Among the 57 patients who completed final follow-up, a euthyroid state was achieved in 26 patients (46%), 27 patients (47%) were rendered hypothyroid and four patients (7%) remained hyperthyroid. Thirty-four patients (60%) remained hyperthyroid at 6 months after the initial radioiodine dose (median dose 126 MBq), and a total of 21 patients required additional radioiodine therapy (median total dose 640 MBq; range 370-1,485 MBq). At 6-month follow-up, of the 29 patients who received a thyroid tissue dose of 90 Gy, 17 (59%) remained hyperthyroid. By comparison, of the 28 patients who received a thyroid tissue dose of 60 Gy, 17 (61%) remained hyperthyroid. No significant difference in treatment response was found (P=0.881). At 6 months, five patients in the 90-Gy group were hypothyroid, compared to two patients in the 60-Gy group (P=0.246). Overall at 6 months, non-responders to low-dose therapy had a significantly larger thyroid gland mass (respective means: 35.9 ml vs 21.9 ml) and significantly higher levels of serum thyroglobulin (respective means: 597.6 microg/l vs 96.9 microg/l). Where low-dose radioiodine treatment of Graves' disease is considered, a dose of 60 Gy will yield a 39% response rate at 6 months while minimising early hypothyroidism. No significant advantage in response rate is gained by using a dose of 90 Gy. For more rapid therapeutic effect at the expense of an increased rate of hypothyroidism, doses in excess of 120 Gy may be required. Ultrasound determination of thyroid mass and measurement of serum thyroglobulin levels may be predictive of those patients who will be less responsive to low-dose therapy.

Adolescent↗
PubMed2001

Glucose, insulin and lipid metabolism in rural Gambians exposed to early malnutrition.

AIMS: There is now substantial evidence to suggest that susceptibility to certain non-communicable diseases may be increased by early undernutrition. In rural Gambia, an annual hungry season reduces birth weight by 200-300 g and increases the prevalence of low birth weight (< 2500 g) from 11% to 24%. The aim of this study was to investigate whether fetal nutritional stress (using season of birth as a proxy measure for prenatal growth retardation) or early childhood malnutrition (using historical anthropometric records) had a residual influence on risk factors for cardiovascular disease in a cohort of rural Gambian adults. METHODS: Two hundred and nineteen adults (mean age = 35.8 years; mean body mass index = 21.3 kg/m2; women = 181) for whom month of birth and infant anthropometric records were available participated in this study. Risk factors for cardiovascular disease were measured. RESULTS: No differences were found between season of birth groups (hungry vs. harvest) and fasting measures of glucose, insulin, lipids, fibrinogen or cortisol, or against 30 and 120 min glucose and insulin levels following an oral glucose tolerance test, or blood pressure. Similarly, these risk factors for adult disease were not related to the subjects' weight-for-age as children. CONCLUSIONS: Moderate-to-severe fetal and childhood malnutrition in rural Gambia caused no detectable impairment of the glucose/insulin axis, or of other cardiovascular disease risk factors in adults remaining lean and fit on a low-fat diet.

Adult↗
PubMed2000

Transversalis fascia rediscovered.

The transversalis fascia is a layer in the make-up of the posterior inguinal wall. It is the deepest, thinnest, and least important layer in terms of the prevention of herniation. It is a segment of the wider endoabdominal fascia. The true posterior wall of the inguinal canal is formed, in varying degrees, by the muscles or aponeuroses of the internal oblique and transversus abdominis. Plainly, Daedalus was not needed to show surgeons and anatomists how to make a labyrinth out of a rabbit hole!

Animals↗
PubMed1999

Fibrinogen and factor VII levels are related to adiposity but not to fetal growth or social class in children aged 10-11 years.

Factors operating in fetal life or during childhood may be important in determining fibrinogen and factor VII concentrations in adult life, and particularly in explaining social gradients in cardiovascular disease risk. In 1994, the authors measured fibrinogen and factor VIIc levels in 641 children aged 10-11 years (61% response rate) from schools in five towns in England and Wales. Birth weight was obtained by maternal recall, and other data on measures of fetal growth were obtained from birth records. Fibrinogen levels were higher in girls (258.8 mg/dl) than in boys (245.4 mg/dl) (95% confidence interval (CI) for difference: 5.5, 21.5). Fibrinogen and factor VIIc levels were linearly related to adiposity, rising by 37.1 mg/dl (95% CI: 24.7, 49.5) and 13.0% of standard (95% CI: 6.3, 19.7), respectively, between the bottom and top quintiles of ponderal index (weight (kg)/height (m)3). Fibrinogen was independently related to heart rate (p < 0.001) and was negatively but nonsignificantly related to measures of physical activity. Factor VIIc was positively correlated with total cholesterol (p < 0.001). No relations were found with measures of fetal growth or social class. These data do not support the concept that fibrinogen or factor VII levels are determined in utero or by social factors in childhood. Adiposity and physical training appear to be the important determinants of fibrinogen and factor VII levels in childhood.

Adipose Tissue↗
PubMed1999

Scintimammography: an adjunctive test for the detection of breast cancer.

OBJECTIVE: To describe the diagnostic utility of scintimammography in patients with a breast mass, including patients who have undergone previous breast surgery or radiotherapy. DESIGN: Descriptive outcome study. SETTING: A university teaching hospital and a private hospital breast clinic in New South Wales. SUBJECTS: 115 consecutively referred women investigated by x-ray mammography and scintimammography before surgical excision biopsy of a breast mass. MAIN OUTCOME MEASURES: Sensitivity and specificity of x-ray mammography and scintimammography in the detection of breast cancer overall, and in women who had or had not undergone previous breast surgery. RESULTS: 44 (38%) patients had undergone previous breast surgery or external beam radiotherapy, including nine with bilateral silicone breast implants. The overall (n = 115) sensitivity for the detection of breast cancer with scintimammography was 84%, compared with 66% for x-ray mammography (P = 0.004), and the respective specificities were 84% and 67% (P = 0.194). For patients who had a history of previous breast surgery, the respective sensitivities of the two tests were 83% and 50% (P = 0.006), compared with 85% and 73% (P = 0.087) for patients who had had no previous surgery. CONCLUSIONS: Scintimammography offers additional diagnostic advantage in the detection of breast cancer in patients who have had previous breast surgery or local radiotherapy.

Adult↗
PubMed1999

Technetium-99m sestamibi scintimammography: the influence of histopathological characteristics, lesion size and the presence of carcinoma in situ in the detection of breast carcinoma.

The limit of detection of invasive carcinoma by scintimammography appears to be >10 mm, but not uncommonly smaller invasive carcinoma is detected in the presence of pre-invasive carcinoma (carcinoma in situ). The aims of this study were to determine whether a relationship exists between the presence of carcinoma in situ and the detection of invasive carcinoma using scintimammography, and to further characterise the influence of lesion size and histopathological characteristics on the diagnostic accuracy of scintimammography for the detection of invasive breast carcinoma. One hundred and seventeen patients were studied prospectively by scintimammography, X-ray mammography and, where appropriate, breast ultrasound prior to excision biopsy of all suspicious breast masses (n=123, 93% palpable). Thirty-five of these patients had a history of previous ipsilateral breast carcinoma. Sixteen percent of biopsy specimens were benign. The remaining specimens were malignant or pre-malignant. The overall diagnostic sensitivity of scintimammography was 84% and the specificity was 80%. The overall sensitivity and specificity for X-ray mammography (n=123), including those examinations combined with breast ultrasound (n=76), were 73% and 69%, respectively. The maximum size of the measured invasive carcinoma ranged from 5 to 80 mm (median 20 mm). Although the maximum size detected for invasive carcinoma in the presence of carcinoma in situ ranged from 3 to 40 mm (median 20 mm), this difference was not statistically significant (P=1.10, t test). Seven cases of carcinoma in situ were not detected by scintimammography. The diagnostic sensitivity of scintimammography for the detection of invasive carcinoma was 98% for lesions 16-25 mm, 91% for lesions 11-25 mm, 78% for lesions >25 mm and 55% for lesions <11 mm. Scintimammography may offer increased diagnostic accuracy for the detection of breast carcinoma, thereby complementing anatomical imaging. This is particularly evident in technically difficult patients who have had previously treated breast cancer. There appears to be no difference in the diagnostic sensitivity of scintimammography for the detection of invasive carcinoma in the presence or absence of carcinoma in situ.

Biopsy, Needle↗
PubMed1999

An anatomic and histologic study of the caruncle.

PURPOSE: To describe the histologic features of the caruncle and to determine its anatomic relationship to the common canaliculus. METHODS: Specimens from preserved and fresh-frozen cadavers were studied histopathologically. RESULTS: The average distance between the external surface of the caruncle and the common canaliculus was 0.85 mm, whereas the shortest distance measured was 0.50 mm. Several histologic abnormalities (oncocytic change, apocrine metaplasia, and microscopic stones) were identified in specimens that appeared clinically normal. CONCLUSION: Caution should be exercised when operations are performed on or near the caruncle to avoid inadvertent damage to the canalicular system.

Aged↗
PubMed1999

Autonomic regulation of lymphatic flow in the lower extremity demonstrated on lymphoscintigraphy in patients with reflex sympathetic dystrophy.

PURPOSE: Nuclear medicine techniques were used to show that the peripheral lymphatics are under autonomic control in much the same way as the blood vessels that supply the same anatomic region. METHODS: Three patients with complex regional pain syndrome type 1 (reflex sympathetic dystrophy) involving a lower extremity were evaluated using three-phase bone scintigraphy and peripheral lymphoscintigraphy. Each patient was treated with ipsilateral chemical lumbar sympathectomy, and lymphoscintigraphy was repeated within several days of the procedure. RESULTS: All three patients had evidence of decreased flow (compared with the contralateral extremity) to normal flow after ipsilateral sympathectomy. Bone scintigraphy, before and after sympathectomy, was difficult to interpret because of the effects of altered weight bearing. Two patients who had unilateral peripheral edema showed marked improvement after sympathectomy and increased lymphatic flow. CONCLUSIONS: Peripheral lymphatic function is controlled by the autonomic nervous system. In reflex sympathetic dystrophy, peripheral edema may be caused by an increased sympathetic stimulus to the lymphatics. Further study of this phenomenon may show that nuclear medicine studies, such as bone scintigraphy and lymphoscintigraphy, can be used to distinguish patients who will benefit from sympathectomy from those who will not, thereby obviating invasive testing and unnecessary invasive treatment.

Adult↗
PubMed1998

Delayed visual maturation and lead pollution.

Three children were born in the Broken Hill Australia lead mining community with delayed visual maturation of the optic nerve (blindness) within a period of 19 months. Because of the association with the lead pollution, the delayed visual maturation was attributed to lead exposure of the fetus during pregnancy. Lead isotopic analyses of the shed deciduous teeth from the three children demonstrate that they were not exposed to increased levels of lead from a mining or any other source during pregnancy and the etiology of the delayed visual maturation must be sought elsewhere.

Child, Preschool↗
PubMed1998

Home care compliance: how to protect yourself.

Home care agencies are operating in a supercharged environment of distrust, thanks to recent regulatory and legislative changes. By establishing and closely following compliance programs, however, they will lower their risk and make improvements in overall agency operations.

Documentation↗
PubMed1998

Lymphoscintigraphy and lymphangiography of lymphangiectasia.

Chronic genital edema secondary to lymphangiectasia and chylous reflux in a 23-yr-old man with Noonan syndrome was investigated by 99mTc sulfur nanocolloid lymphoscintigraphy and bipedal contrast lymphangiography. Lymphoscintigraphy showed a delayed lymphatic flow pattern in the pelvis, abdomen and chest consistent with lymphangiectasia and abnormal lymphatic flow dynamics. Lymphangiography showed dilated and tortuous abnormal lymphatics in the abdomen and pelvis. Ligation of incompetent retroperitoneal lymph vessels and lymphaticovenous anastamosis were performed, resulting in clinical improvement. Lymphangiectasia has been described previously in Noonan syndrome, but it is relatively uncommon below the diaphragm. This case demonstrates the use of lymphoscintigraphy and lymphangiography in providing important physiological and anatomical information before surgical intervention. Careful presurgical planning using such tests also allows the most appropriate operation to be performed.

Adult↗
PubMed1997

The initial Australian experience of technetium-99M sestamibi scintimammography: a complementary test in the management of breast cancer.

BACKGROUND: The adjunctive role of Tc-99m sestamibi scintimammography in the diagnosis and management of patients with a high probability of breast cancer was assessed. METHODS: A descriptive study of 16 patients with palpable masses who had a high probability of breast cancer as determined by investigations such as cytology and conventional imaging techniques were carried out. All patients were followed-up to surgery. RESULTS: Scintimammography true positive results were found in 14 of 18 lesions detected in 16 patients. There were two false-positives which included one lobar carcinoma in situ lesion and one complex sclerosing lesion, and one false-negative patient. Scintimammography detected abnormal radiotracer uptake in four of six patients with axillary metastases. Three patients had clinically and mammographically undetected multicentric disease detected on scintimammography which allowed appropriate modification of surgical excision. Breast cancer was detected in a patient with breast prostheses. CONCLUSIONS: Scintimammography would appear to have a useful adjunctive role to mammography in the diagnosis of breast cancer. The diagnosis of breast cancer may be enhanced in difficult cases and the detection of multicentricity on scintimammography may have an impact on subsequent surgical management.

Adult↗
PubMed1996

Importance of monitoring family members in establishing sources and pathways of lead in blood.

High precision lead isotope measurements were undertaken to establish the sources and pathways in blood and environmental samples of five families from the Broken Hill lead mining community, New South Wales, Australia. The five families were selected from 27 families investigated to illustrate the different sources and pathways of lead into blood and the importance of monitoring the whole family. The results illustrate that although the major source of lead is from the orebody, paint and petrol can be significant contributors to both house dust and blood leads. The results also show that the sources and pathways can be from the father's occupation and hence monitoring of families is important, especially in high risk locations. In two cases, the elevated blood leads in the children did not derive from their current residence but from other residences in the community.

Adult↗
PubMed1996

Non-orebody sources are significant contributors to blood lead of some children with low to moderate lead exposure in a major lead mining community.

High precision lead isotope ratios in blood from 58 children aged 1-11 years from the Broken Hill lead mining community have been measured to determine the source and pathways of lead in their blood. Sources of lead are from the Pb-Zn-Ag orebody (lead), from paint and from petrol. Thirty-five of the 58 children (60%) had blood leads (PbB) > or = 0.72 micromol/l (15 microg/dl), the current level of 'personal exposure and source remediation/abatement' compared with a 'background' level of approximately 0.29 micromol/l (6 microg/dl), estimated from adult females who were generally mothers of the children. Six of 17 children aged 7 years or older, had PbBs > or = 0.72 micromol/l (15 microg/dl). Even though the orebody lead is the major contributor to PbB in Broken Hill children, of the 35 children whose PbB is > or = 0.72 microm/l (15 microg/dl), 12 (34%) have approximately 50% or more of their PbB derived from sources such as paint and petrol or both by isotopic identification. The identification of elevated PbB in older children is a concern, especially for females, as there is potential for release of endogenous lead during pregnancy and lactation.

Child↗