Search PubMed⌕ Search

Biomedical subjects

D S Bell

Publications and source records attributed to D S Bell.

At least 55 records · Page 3Linked to original sources
PubMed1995

Automated quantification of color Doppler signals: a preliminary study in breast tumors.

PURPOSE: To quantify color Doppler (CD) signals reflected by breast lesions to improve differential diagnosis and serial comparisons. MATERIALS AND METHODS: Frame-grabbed color-capture scans were remapped to original velocities on a pixel-by-pixel basis for statistical analysis. Total CD area and its percentage, peak and mean velocities, standard deviation of velocity, and integral CD velocity and its percentage were calculated. These indexes were applied to scans of 44 cancers, 16 fibroadenomas, and 14 benign breast changes in 74 patients. RESULTS: With the region of interest confined to the lesion and a 5-mm margin, no CD signals were reflected by the benign breast changes. All carcinomas and 12 fibroadenomas (those that were vascular) reflected CD signals, and, except for mean and peak velocity, all scores for cancers were significantly higher than for fibroadenomas (P < .0001). Integral CD velocity was the best discriminator, with no overlap between carcinomas (range, 1,128-50,228 cm3/sec) and fibroadenomas (range, 0-1,027 cm3/sec). CONCLUSION: Automatic CD quantification improved differential diagnosis of breast masses.

Adult↗
PubMed1995

Diabetic cardiomyopathy. A unique entity or a complication of coronary artery disease?

The increased incidence of congestive heart failure and the increased mortality and morbidity in the diabetic patient following myocardial infarction or coronary artery bypass graft can be explained by the presence of diabetic cardiomyopathy. Noninvasive studies in young diabetic patients show no cardiac abnormality, but in older diabetic patients mild cardiac diastolic dysfunction is detectable. This mild cardiomyopathy can become clinically detectable in the presence of hypertension and can be severe in the presence of myocardial ischemia. Microvascular disease is unlikely to cause diabetic cardiomyopathy. Cellular changes, including defects in calcium transport and fatty acid metabolism, may lead to myocellular hypertrophy and myocardial fibrosis, initially causing diastolic dysfunction that may advance to systolic dysfunction. Glycemic control, energetic detection and treatment of hypertension with appropriate antihypertensive agents, and early detection and treatment of ischemic heart disease are essential in preventing and treating diabetic cardiomyopathy.

Animals↗
PubMed1995

Lack of long-term diabetic complications in spite of poor glycemic control in twins with pure gonadal dysgenesis.

BACKGROUND: The prepubertal years have little effect on the chronic complications of diabetes. Animal studies have shown castration prevents diabetic complications. No previous data on untreated agonadal human diabetic subjects is available. CASE HISTORY: Clinical study of untreated agonadal twins with insulin-dependent diabetes for presence of chronic complications of diabetes. In spite of the twins' poor glycemic control, no evidence of the chronic complications of diabetes was found. CONCLUSIONS: The absence of gonadal sex steroids in the diabetic patient may have a protective effect against the development of the chronic complications of diabetes.

Adult↗
PubMed1995

Adaptive speckle reduction for improving the differential diagnosis of breast lesions.

Adaptive speckle reduction could mask diagnostic features and adversely affect diagnosis of focal breast lesions. Four radiologists assessed focal breast lesions (29 malignant and 31 benign) by blind review of representative static B-mode scans before and after adaptive speckle reduction processing, scoring 14 diagnostic features for breast cancer and recording their opinions on the diagnosis and on how adaptive speckle reduction affected interpretation of each feature. No adverse affect on diagnosis of malignant (P = 0.756) or benign (P = 1.000) breast lesions was found, despite some differences in scoring of the diagnostic features after adaptive speckle reduction. Observer recognition of most diagnostic features was easier after adaptive speckle reduction (e.g., edge definition [50% of cases], edge regularity [40%], lesion texture [44%], and lesion echogenicity [35%]).

Adult↗
PubMed1994

Chronic fatigue syndrome update. Findings now point to CNS involvement.

Neither Epstein-Barr virus nor human herpesvirus 6 appears to play a causative role in chronic fatigue syndrome. The possibility that a novel human retrovirus may be present in patients with the syndrome needs further study. A number of abnormalities found in patients with chronic fatigue syndrome point to central nervous system (CNS) involvement. These include immunologic abnormalities, indications of pituitary and hypothalamic involvement, abnormal basal plasma levels of certain neurotransmitter metabolites, and cerebral perfusion abnormalities. The symptom pattern of chronic fatigue syndrome may eventually be explainable in terms of CNS dysfunction.

Brain Diseases↗
PubMed1994

Variability of the pancreatic islet beta cell/liver (GLUT 2) glucose transporter gene in NIDDM patients.

The purpose of these experiments was to test the hypothesis that impaired glucose-stimulated insulin secretion in NIDDM is due to mutations in the islet beta cell/liver glucose transporter (GLUT 2) gene. Using oligonucleotide primers flanking each of the 11 exons, the structural portion of the gene was studied by PCR-SSCP analysis. DNA from African-American females (n = 48), who had gestational diabetes but developed overt NIDDM after delivery, was studied. Each SSCP variant was sequenced directly from genomic DNA. Two amino acid substitutions from the previously reported sequence were found, one in exon 3 and the other in exon 4B. Four additional silent mutations in the coding region, and six intron mutations outside the splice junction consensus sequences, were also identified. The mutation GTC x ATC in exon 4B substituted Val197 to Ile197. This amino acid substitution was found in only one NIDDM patient in a single allele, and was not found in 52 control subjects. This residue exists in the fifth membrane spanning domain, and Val at this position is conserved in mouse and rat GLUT 2, and human GLUT 1 to GLUT 4. The other codon change in exon 3, ACT x ATT, substituted Thr110 to Ile110 in the second membrane spanning domain. To determine the frequency of this non-conservative amino acid substitution, a PCR-LCR assay was developed. This assay was simple and highly specific for detection of this single nucleotide substitution. The allelic frequency of the ATT (Ile110) in NIDDM patients (39.6%, n = 48) and that in controls (47.1%, n = 52) did not differ (p = 0.32, Fisher's exact test).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Glucokinase gene in gestational diabetes mellitus: population association study and molecular scanning.

Mutations of the glucokinase gene result in early-onset familial Type 2 (non-insulin-dependent) diabetes mellitus, and several members of the mutant glucokinase kindreds were originally diagnosed as having gestational diabetes. This study examined the glucokinase gene in 270 American Black women, including 94 with gestational diabetes whose diabetes resolved after pregnancy (gestational diabetes only), 77 with gestational diabetes who developed Type 2 diabetes after pregnancy (overt diabetes), and 99 normal control subjects who were recruited during the peripartum period. Two simple sequence repeat polymorphisms flanking either end of the glucokinase gene were evaluated. No association was found between glucokinase alleles and gestational diabetes only or overt diabetes, after adjustment for multiple comparisons. To detect single base changes, all 11 exons and proximal islet and liver promoter regions were examined by polymerase chain reaction plus single-stranded conformational polymorphism analysis in 45 gestational diabetes only patients who had not yet developed Type 2 diabetes. Nine coding region variants were identified: Ala11 (GCC) to Thr11 (ACC) in islet exon 1, and 8 variants either in untranslated regions or in the third base of a codon. Four variant sites were found in introns, but none in splicing consensus sequences. Analysis of the promoter regions revealed two common variants, G-->A at islet -30 (24%), and G-->A at liver -258 (42%). The frequencies of the promoter variants, determined by allele specific polymerase chain reaction analysis, but did not differ among the three groups. Thus, no significant coding sequence glucokinase mutations were found in 90 alleles from 45 patients with gestational diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A nomothetic-idiographic study of daily psychological stress and blood glucose in women with type I diabetes mellitus.

Although there has been some study of the extralaboratory generality of stress effects on diabetic metabolism, analysis of the diabetic response to everyday life stress is needed. The secondary objective of this study was to investigate whether personal characteristics moderate the daily stress-glucose relationship. Twenty-five women with Type I diabetes completed measures of internality and self-esteem and subsequently monitored daily stress and blood glucose for 30 consecutive days. Data were analyzed by both time-series and conventional correlational analyses. Glucose was higher on high-stress days than on low-stress days, with one-third of the sample showing significant positive associations between stress and same-day glucose. However, stress showed little relation to next-day glucose. Personal characteristics failed to explain differences in stress-glucose associations. Implications for practice and future research are presented.

Adolescent↗
PubMed1994

Primary juvenile fibromyalgia syndrome and chronic fatigue syndrome in adolescents.

Chronic fatigue syndrome (CFS) and primary juvenile fibromyalgia syndrome (PJFS) are illnesses with a similar pattern of symptoms of unknown etiology. Twenty-seven children for whom CFS was diagnosed were evaluated for fibromyalgia by the presence of widespread pain and multiple tender points. Eight children (29.6%) fulfilled criteria for fibromyalgia. Those children who met fibromyalgia criteria had a statistically greater degree of subjective muscle pain, sleep disturbance, and neurological symptoms than did those who did not meet the fibromyalgia criteria. There was no statistical difference between groups in degree of fatigue, headache, sore throat, abdominal pain, depression, lymph node pain, concentration difficulty, eye pain, and joint pain. CFS in children and PJFS appear to be overlapping clinical entities and may be indistinguishable by current diagnostic criteria.

Adolescent↗
PubMed1994

Characteristics of severe hypoglycemia in the patient with insulin-dependent diabetes.

To avoid, delay, or ameliorate the microvascular complications of diabetes, intensive insulin therapy with the goal of normoglycemia is required. In most patients with insulin-dependent diabetes mellitus (IDDM), this cannot be achieved because of severe hypoglycemia, which is one of the major causes of morbidity in diabetic patients. To assess the frequency and characteristics of severe hypoglycemia in a single diabetologist's practice, we surveyed 211 consecutive patients with IDDM for a history of severe hypoglycemia (SH), defined as events requiring the assistance of another person. Of these 211 patients, 135 (64%) had at some time had SH. Those with SH had a longer duration of IDDM, currently took more insulin injections, had a higher prevalence of neuropathy and nephropathy, and were less likely to be using human insulin. No difference was found in age, average glycosylated hemoglobin level, frequency of home glucose monitoring, or presence of retinopathy. Half of the patients with SH had confusion and were treated with glucose orally. The remainder were in coma and received i.v. glucose or IM glucagon. Perceived causes of SH were lack of food, excessive insulin, and unusual exercise. We conclude that the frequency of SH is underestimated in clinical practice. Risk factors for SH are longer duration of IDDM, presence of neuropathy and nephropathy, and use of animal insulin. Better education in avoidance and treatment of SH would reduce the morbidity of SH.

Adult↗
PubMed1994

Genes within the major histocompatibility complex predict NIDDM in African-American women in Alabama.

OBJECTIVE: To test the hypothesis that genes within the major histocompatibility complex (MHC) are associated with gestational diabetes mellitus (GDM) and, subsequently, non-insulin-dependent diabetes mellitus (NIDDM) in African-American women. RESEARCH DESIGN AND METHODS: African-American women who presented with GDM were compared with pregnant African-American control subjects. Following pregnancy, GDM patients were assessed at various intervals of time (median = 6 years) to determine whether they had developed diabetes. RESULTS: GDM patients who required insulin during pregnancy possessed a significantly higher frequency of A33, DR2, DR9, and BF-S phenotypes than control subjects. GDM patients who subsequently developed NIDDM had a significantly higher frequency of B41, DR2, and BF-S and a lower frequency of DR1 and DR6 phenotypes than control subjects. Even after controlling for age and body mass index, B41 and DR2 were independent predictors of developing insulin-requiring GDM and NIDDM in GDM subjects. CONCLUSIONS: These results suggest that either one or more genes within the MHC are involved in the etiology of NIDDM.

Alabama↗
PubMed1994

Stroke in the diabetic patient.

A higher prevalence of stroke is found in the patient with both diagnosed and undiagnosed diabetes and glucose intolerance. Because of local cerebral acidosis caused by ischemia and hyperglycemia, morbidity and mortality from a stroke are increased. Most studies show that individuals with admission serum glucose > 120 mg/dl (6.7 mM) have a higher morbidity and mortality from a stroke. The prevalence of cerebral infarcts, especially lacunar infarcts, is increased and the prevalence of subarachnoid hemorrhage, cerebral hemorrhage, and transient ischemic attacks are decreased in the diabetic patient. Age, race, hypertension, and the presence of diabetic nephropathy and coronary and peripheral vascular disease are risk factors for stroke in the diabetic patient, whereas obesity, smoking, hyperlipidemia, and glycemic control are not. Investigation and treatment of the diabetic patient with a stroke is discussed.

Cerebrovascular Disorders↗
PubMed1994

Evaluation of UltraSTAR: performance of a collaborative structured data entry system.

The UltraSTAR structured data entry system is now in routine use for reporting ultrasound studies at Brigham and Women's Hospital, having been used for 3722 reports in its first ten months of service. Reports entered through GUI-based forms are uploaded via HL7 to a radiology information system and distributed through a hospital network. UltraSTAR introduces collaborative reporting, in which nonmedical and medical staff collaborate to produce a single report for each patient visit. Performance of UltraSTAR was measured as user satisfaction, data entry time, report completeness, free text annotation rate, and referring-physician satisfaction with reports. Results show high satisfaction with UltraSTAR among radiologists and acceptance of the system among ultrasound technicians. Data entry times averaged 5.3 minutes per report. UltraSTAR reports were slightly more complete than comparable narrative reports. Free text annotations were needed in only 25.2% of all UltraSTAR reports. Referring physicians were neutral to slightly positive toward UltraSTAR's outline-format reports. UltraSTAR is successful at structured data entry despite somewhat long reporting times. Its success can be attributed to efficiencies from collaborative reporting and from integration with existing information systems. UltraSTAR shows that the advantages of structured data entry can outweigh its difficulties even before problems of data entry time and concept representation are solved.

Attitude to Computers↗
PubMed1993

Insulin resistance. An often unrecognized problem accompanying chronic medical disorders.

Insulin resistance is associated with a number of risk factors for atherosclerosis, including glucose intolerance, hypertension, and dyslipidemia. Management of these disorders should include an attempt to reduce insulin resistance and certainly not to increase it. For example, when possible, thiazide diuretics and beta blockers should be avoided for treating hypertension, because they increase insulin resistance and, in diabetic patients, adversely affect glycemic control. Since exercise, weight loss, and cessation of smoking reduce insulin resistance, they are often helpful components of a treatment regimen for patients who have chronic medical disorders that are associated with insulin resistance.

Acanthosis Nigricans↗
PubMed1993

Serum angiotensin-converting enzyme as a marker for the chronic fatigue-immune dysfunction syndrome: a comparison to serum angiotensin-converting enzyme in sarcoidosis.

PURPOSE: To study the reliability of a serum angiotensin-converting enzyme (ACE) assay as a marker for the chronic fatigue-immune dysfunction syndrome (CFIDS), and to compare some enzyme characteristics of ACE in CFIDS with that in sarcoidosis. PATIENTS AND METHODS: Forty-nine patients with CFIDS and 56 endemic control subjects from Lyndonville, New York, and Charlotte, North Carolina; plus 23 untreated patients with active sarcoidosis, 24 with sarcoidosis receiving corticosteroid therapy, and 32 patient controls without sarcoidosis from California. Serum ACE levels were determined with a spectrophotometric method. The effect of freezing and thawing and the effect of storage at 4 degrees C were compared between CFIDS and sarcoidosis samples. RESULTS: Serum ACE levels were elevated in 80% of patients with CFIDS and 30% of endemic control subjects as compared with 9.4% of nonendemic California control subjects. The ACE activity in CFIDS differed from that in sarcoidosis because of its lability with storage at 4 degrees C in CFIDS and its partial activation with freezing and thawing. Thus, ACE activity was elevated in the majority of CFIDS patients either upon initial assay or upon a subsequent assay after refreezing. ACE activity was elevated in 87% of patients with active sarcoidosis and was not affected by storage or freezing and thawing. CONCLUSIONS: Serum ACE elevations may be a useful marker for CFIDS, especially if a method can be developed to distinguish ACE in CFIDS from that in sarcoidosis. The sensitivity for CFIDS was 80%, with 68% specificity in an endemic area. The increased prevalence of serum ACE elevations in endemic controls as compared with nonendemic controls suggests that an ACE increase may be an early manifestation of CFIDS and supports the concept that CFIDS is a definite disease state.

Adult↗
PubMed1993

Compensation for the signal processing characteristics of ultrasound B-mode scanners in adaptive speckle reduction.

A systematic method to compensate for nonlinear amplification of individual ultrasound B-scanners has been investigated in order to optimise performance of an adaptive speckle reduction (ASR) filter for a wide range of clinical ultrasonic imaging equipment. Three potential methods have been investigated: (1) a method involving an appropriate selection of the speckle recognition feature was successful when the scanner signal processing executes simple logarithmic compressions; (2) an inverse transform (decompression) of the B-mode image was effective in correcting for the measured characteristics of image data compression when the algorithm was implemented in full floating point arithmetic; (3) characterising the behaviour of the statistical speckle recognition feature under conditions of speckle noise was found to be the method of choice for implementation of the adaptive speckle reduction algorithm in limited precision integer arithmetic. In this example, the statistical features of variance and mean were investigated. The third method may be implemented on commercially available fast image processing hardware and is also better suited for transfer into dedicated hardware to facilitate real-time adaptive speckle reduction. A systematic method is described for obtaining ASR calibration data from B-mode images of a speckle producing phantom.

Algorithms↗