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Biomedical subjects

R Firth

Publications and source records attributed to R Firth.

At least 19 recordsLinked to original sources
PubMed1998

Diabetic retinopathy in Down's syndrome.

AIM: To determine the prevalence of diabetic retinopathy in patients with Down's syndrome and diabetes mellitus. METHODS: Nine patients with Down's syndrome and diabetes mellitus were assessed. Factors recorded included type and duration of diabetes, level of diabetic control, blood pressure, urinalysis, and results of ophthalmological examination. RESULTS: The duration of diabetes ranged from 8 to 41 years (mean 17.6 years). All had satisfactory glycaemic control and blood pressure measurements on the low side of normal (mean 106.6/70 mm Hg). One patient had early background diabetic retinopathy. The remainder had no evidence of diabetic retinopathy. CONCLUSION: The low prevalence of diabetic retinopathy in these Down's syndrome patients, despite the long duration, is an interesting finding. It suggests some inherent protective factor against the development of diabetic retinopathy in this patient subgroup.

Adult↗
PubMed1997

Prevalence of diabetic retinopathy in patients with diabetes mellitus diagnosed after the age of 70 years.

AIMS/BACKGROUND: A hospital based prevalence study was undertaken to estimate the prevalence of diabetic retinopathy (DR) in patients diagnosed as having diabetes mellitus after the age of 70 years. The prevalence of visually threatening retinopathy at the time of diagnosis of diabetes was also determined. The association between prevalence of DR and duration of diabetes mellitus, mode of treatment, HbA1c levels, presence of hypertension, and sex of patient was examined and a comparison was drawn between this study and earlier prevalence studies of DR in older type II diabetics. METHODS: Using data on the Irish Diabetic Retinopathy Register located in the Mater Misericordiae Hospital, Dublin, all patients who were diagnosed as having type II diabetes mellitus after the age of 70 years were invited to attend for ophthalmic review. Medical records were examined to determine the duration of diabetes mellitus, mode of treatment, recent HbA1c levels, and the presence of systemic hypertension. RESULTS: Of the 150 patients examined, 21 (14%) had some form of DR and 10 of these patients (6.6%) had visually threatening retinopathy or previously treated visually threatening retinopathy. Five patients (3.3%) presented with visually threatening retinopathy at the time of diagnosis of diabetes. Those patients with DR had a significantly higher median duration of diabetes (5.0 years) compared with those patients without DR (3.5 years). A significantly higher proportion of patients with DR required treatment with insulin and a correspondingly lower proportion of patients without DR were controlled on diet alone. There was no significant association between prevalence of DR and HbA1c levels, systemic hypertension, or sex of patient. There was a lower overall prevalence of DR in comparison with earlier studies. CONCLUSIONS: The prevalence of DR in these elderly type II diabetics is lower than than previously reported in patients with type II disease but a small percentage of patients had visually threatening retinopathy at presentation. Longer duration of diabetes and insulin use were associated with a significantly increased prevalence of DR. All elderly type II diabetic patients require thorough ophthalmic examination near to the time of first presentation and thereafter at regular intervals.

Aged↗
PubMed1996

Tethered cord syndrome.

OBJECTIVE: To briefly discuss a case of tethered spinal cord syndrome, and to acquaint the reader with one of many important differential considerations among patients presenting with low back and leg pain. FEATURES: A 32-yr-old woman sought treatment at a private chiropractic clinic for a 6-month history of low back pain with intermittent diffuse bilateral leg pain and numbness. Plain films of the lumbar spine revealed no abnormality. Magnetic resonance imaging demonstrated a tethered spinal cord. INTERVENTION: The abbreviated filum terminale was surgically corrected. CONCLUSIONS: Tethered cord syndrome, a significant finding, is likely to have been responsible for the patient's signs and symptoms. Magnetic resonance imaging is particularly helpful in evaluating spinal cord deformity, and may provide important information on patients not responding to chiropractic care.

Adult↗
PubMed1994

Non-linkage of the glucagon-like peptide 1 receptor gene with maturity onset diabetes of the young.

Glucagon-like peptide-1 (GLP-1) is a hormone derived from the preproglucagon molecule that is secreted by intestinal L cells and stimulates insulin secretion from beta cells. The GLP-1 receptor is a candidate gene for diabetes mellitus, as mutations may induce the impaired insulin response that is a characteristic feature of NIDDM. To study the relationship between the GLP-1 receptor gene and NIDDM, linkage of a microsatellite polymorphism flanking the GLP-1 receptor gene with diabetes was investigated in three Caucasian families with MODY and in the nuclear families of 12 NIDDM probands. A cumulative LOD score -8.50 excludes linkage in these MODY pedigrees. A LOD score of -1.24 in the NIDDM nuclear pedigrees makes linkage improbable. Mutations in or near the GLP-1 receptor gene are unlikely to be the major cause of the inherited predisposition to NIDDM in Caucasian pedigrees, but we cannot exclude a role for this locus in a polygenic model or a major role in some pedigrees.

Base Sequence↗
PubMed1994

A comparison of radiographic signs of degeneration to corresponding MRI signal intensities in the lumbar spine.

OBJECTIVES: To evaluate plain film radiographic findings of lumbar intervertebral disk degeneration. DESIGN: A cross-sectional observational design was employed. Contingency tables were constructed to evaluate the relationships between radiographic findings of degeneration and the corresponding MRI signal intensities of the inner intervertebral disk. SETTING: Twenty-four consecutive cases were retrospectively selected from an MRI imaging center. PATIENTS: No exclusion was made on the basis of age or sex. MAIN OUTCOME MEASURES: Radiographic findings of IVD degeneration include: Narrowed disk space, osteophyte formation, end-plate sclerosis, vacuum phenomenon, end-plate irregularity and Schmorl's node formation. The inner IVD signal intensity of the sagittal T2-weighted MRI image was visually categorized by three radiologists. The signal intensities were divided into low, medium and high categories. MAIN RESULTS: Visually reduced disk height, osteophytes and eburnation all demonstrate significant relationships with MRI signal intensity. Due to their infrequency, no significant relationships could be found with vacuum phenomena, end-plate irregularity, and Schmorl's nodes when compared to MRI signal intensity. CONCLUSIONS: In conclusion, visually reduced disk height is frequently associated with decreased signal intensity and, therefore, significantly indicates internal disk derangement. Osteophytes are more commonly present when the signal intensity is low. However, high signal intensity is associated with osteophytic change as well. Therefore, osteophytic change is less sensitive and accurate to early inner disk degenerative change. When osteophytes and reduced disk height are present together, a stronger prediction of degeneration is possible then when either finding is present alone. Due to their infrequency, eburnation, vacuum phenomena, end-plate irregularity and Schmorl's nodes are less helpful indicators of degeneration.

Adult↗
PubMed1993

Fine needle aspiration cytology of thyroid nodules: review of 36 months experience.

Studies suggest that fine needle aspiration of thyroid nodules is a sensitive and specific tool for the detection of thyroid cancers thus preventing unnecessary operations. This technique was introduced in our institution in 1987 and performed where indicated under strictly defined criteria. We reviewed the aspirates performed over a 36 month period to critically evaluate the role of this procedure. Review was limited to F.N.A.s of nodules considered to be potentially malignant by conventional criteria and hence all the following criteria needed to be fulfilled: (1) solitary or dominant nodules in a multinodular goitre, (2) cold on isotope scanning, (3) solid or complex cystic nodule on ultrasonography. During the period May 1987 to May 1990 88 aspiration procedures were performed on 77 patients. 93% of the 77 patients had adequate aspirates and of these approximately 30% were considered suspicious or malignant. The overall resection rate was 23.4% which is approximately one third of the rate expected should suspicion have been based solely on conventional imaging criteria. The yield of neoplasia (adenoma and carcinoma) at resection was 89%. We found FNA to be a very useful adjunct in the management of nodular thyroid disease when used in conjunction with clinical laboratory and radiological evaluation. It is safe, inexpensive and provides useful additional information towards making appropriate decisions in an area beset with uncertainty.

Biopsy, Needle↗
PubMed1992

The timing of delivery in diabetic pregnancy: a 10-year review.

The approach of term in the pregnancy of a diabetic woman is a time of anxiety for patient and physician alike. The impact of a conservative approach to the timing of delivery is outlined in this review of the clinical course and outcome of 276 pregnancies of diabetic women, delivered at the National Maternity Hospital, Dublin between 1981 and 1990. The mean gestation at delivery was 39 weeks, 229 patients (83%) delivered at or beyond 38 weeks and 112 patients (41%) delivered at or beyond 40 weeks. The overall induction of labour rate was 27% and the elective Caesarean section rate was 19%. Sixty seven percent of patients achieved a normal delivery, the forceps rate was 5%, and 28% of patients were delivered by Caesarean section. There were 16 perinatal deaths in the series, with 7 due to lethal malformations. There were 5 deaths of normally formed infants occurring at or beyond 38 weeks' gestation. All of these 5 deaths had been preceded by clinically apparent polyhydramnios or macrosomia and recognized poor control. This study stresses the value of strict diabetic control in the management of diabetic pregnancy and highlights the significance of polyhydramnios and macrosomia as indicators of risk approaching term in diabetic pregnancy.

Adolescent↗
PubMed1987

Insulin action in non-insulin-dependent diabetes mellitus: the relationship between hepatic and extrahepatic insulin resistance and obesity.

To determine the contribution of obesity to the insulin resistance of non-insulin-dependent diabetes mellitus, insulin dose response curves for suppression of glucose production and stimulation of glucose utilization were generated in lean and obese diabetic patients and compared to those observed in weight-matched nondiabetic subjects. Glucose utilization during 0.4, 1.0, and 10.0 mU/kg x min insulin infusions (producing insulin concentrations ranging from approximately 50 to 2,000 microU/mL) was lower (p less than .02 to .001) in lean and obese diabetic patients compared to weight-matched nondiabetic subjects indicating insulin resistance. Glucose utilization was not correlated with obesity in the diabetic subjects. Suppression of glucose production was impaired (P less than .03 and .001) in both the lean and obese diabetic subjects at physiologic but not supraphysiologic insulin concentrations. We conclude that patients with NIDDM have both hepatic and extrahepatic insulin resistance, the severity of which appears to be independent of the degree of obesity.

Blood Glucose↗
PubMed1987

Effects of tolazamide and exogenous insulin on pattern of postprandial carbohydrate metabolism in patients with non-insulin-dependent diabetes mellitus. Results of randomized crossover trial.

To determine whether therapy with exogenous insulin or sulfonylureas results in a postprandial pattern of carbohydrate metabolism in patients with non-insulin-dependent diabetes mellitus (NIDDM) that resembles that in nondiabetic individuals, we employed a dual-isotope technique combined with forearm catheterization to examine meal disposition in NIDDM patients, before and after 3 mo of therapy with tolazamide and after 3 mo of therapy with exogenous insulin, with a randomized crossover design. Results were compared with those observed in nondiabetic subjects. Although both forms of therapy improved chronic glycemic control (glycosylated hemoglobin concentration went from 9.6 +/- 0.7 to 7.6 +/- 0.5 and 7.1 +/- 0.2%, respectively, P less than .01), exogenous insulin resulted in a lower postprandial glycemic response than tolazamide (P less than .001). Both agents comparably increased (P less than .01) fasting and integrated postprandial insulin concentrations. However, the initial rate of postprandial increase was greater with exogenous insulin (P less than .05). Tolazamide (P less than .05) but not exogenous insulin increased postprandial C-peptide concentrations. However, tolazamide did not improve the deficient early insulin release. Both agents (P less than .05) lowered postabsorptive hepatic glucose release (from 2.8 +/- 0.3 to 2.3 +/- 0.2 mg . kg-1 . min-1), but not to normal rates (1.8 +/- 0.1 mg . kg-1 . min-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1986

The role of autoregulation of the hepatic glucose production in man. Response to a physiologic decrement in plasma glucose.

In man, a decrease in plasma glucose concentration results in a compensatory increase in hepatic glucose release. Studies in vitro have suggested that a low glucose concentration per se may directly stimulate hepatic glucose release, an effect often referred to as autoregulation. Whether autoregulation occurs in man in response to a physiologic decrement in blood glucose is not known. Therefore, seven healthy, nonobese subjects were studied on two occasions to determine the role of autoregulation in mediating the increase in glucose production that accompanies a physiologic decrement in plasma glucose concentration. On both occasions, plasma glucose concentrations were clamped successively at 95, 65, and 95 mg/dl for 2 h each. Insulin (approximately 14 microU/ml) and glucagon (approximately 70 pg/ml) were maintained constant on both occasions by an infusion of somatostatin and insulin. Phentolamine and propranolol also were infused on one occasion to produce combined alpha- and beta-adrenergic blockade. In the absence of adrenergic blockade, glucose production increased by approximately 1.3 mg/kg X min when the plasma glucose concentration was decreased from 95 to 65 mg/dl and decreased by approximately 1.5 mg/kg X min when glucose was increased from 65 to 95 mg/dl. In the presence of adrenergic blockade, the increase and decrease in glucose production averaged 0 and 0.5 mg/kg X min, respectively, representing 70-100% inhibition. We conclude that, in the presence of low physiologic insulin concentrations, autoregulation is not a major contributor to the hepatic response to a physiologic decrement in plasma glucose concentration in man.

Adult↗
PubMed1984

Visual evoked response changes following intrathecal injection of water-soluble contrast media: a possible method of assessing neurotoxicity and a comparison of metrizamide and iopamidol.

An investigation was carried out to ascertain if there was a change in visual evoked responses following the intrathecal injection of water-soluble contrast media for myeloradiculography and if this change provided an indication of neurotoxicity as assessed by the onset of headache during a period of 20 h following the radiological examination. The patients were unselected and examined, when facilities for measuring the visual evoked response were available, immediately before and at 1 and 20 h after the examination. Control readings were carried out before, 1 h and 20 h after lumbar puncture in patients who did not have an injection of contrast medium. The first 25 patients in the series received metrizamide; when iopamidol became available a change to the newer medium was made and iopamidol was used on all subsequent patients. All the injections were carried out by the same radiologist and the patients were kept in hospital overnight and interviewed the next morning, avoiding a specific reference to headache unless the patient denied all symptoms. It was found that the latency of the visual evoked response was affected in some cases by the presence of contrast medium in the cerebrospinal fluid and that there was a correlation between the severity of headaches and the delay in the visual evoked response at the 20 h post-myelogram measurement, but not at 1 h after the examination. It would appear, therefore, that the visual evoked response measurement is a valid method of assessing, in the short term, the neurotoxicity of intrathecal water-soluble contrast media and that, on this evidence, iopamidol is less neurotoxic than metrizamide. We are not aware of any long-term complications resulting from the use of either contrast medium.

Contrast Media↗
PubMed1980

Congenital dyserythropoietic anaemia type II (HEMPAS): a family study.

A family having two affected siblings with congenital dyserythropoietic anaemia type II (HEMPAS) is described. The proband was diagnosed after referral for investigation of haemolytic anaemia. Clinical evaluation and in vivo red cell (RBC) survival and the sequestration studies in the proband indicated that the anaemia was due to a combination of ineffective erythropoiesis and premature destruction of RBCs in the spleen. Scanning electron microscopic examination of peripheral RBCs was undertaken and is reported. The polypeptide composition of RBC membranes was also examined using polyacrylamide gel electrophoresis after solubilisation in sodium dodecyl sulphate. These results are also reported.

Anemia, Dyserythropoietic, Congenital↗
PubMed1969

Large-scale screening by the automated Wassermann reaction.

In view of the drawbacks in the use of the Kahn test for large-scale screening of blood donors, mainly those of human error through work overload and fatiguability, an attempt was made to adapt an existing automated complement-fixation technique for this purpose. This paper reports the successful results of that adaptation.

Automation↗