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Biomedical subjects

M G Fitzgerald

Publications and source records attributed to M G Fitzgerald.

At least 19 recordsLinked to original sources
PubMed1992

Chromosomal assignment of 46 brain cDNAs.

Expressed sequence tags (ESTs) have been obtained from several hundred brain cDNAs as an initial effort to characterize expressed brain genes. These ESTs will become tools for human genome mapping and they will also provide candidate causative genes for inherited disorders affecting the central nervous system. We have developed a procedure for the rapid chromosomal assignment of these ESTs: cDNA sequences are first analyzed by a computer program to determine regions likely not to be interrupted by introns in the genomic DNA. A pair of oligonucleotide primers is then designed to amplify this region by the polymerase chain reaction using DNA template from human-rodent somatic cell hybrid chromosomal panels. The chromosomal assignment of the cDNA is determined by studying the segregation of the amplified products in these panels. In this paper we describe the mapping of 46 brain ESTs, as well as observations on the amplification of rodent sequences.

Animals↗
PubMed1992

Rapid and reliable fluorescent cycle sequencing of double-stranded templates.

Automated DNA sequencing is an extremely valuable technique which requires very high quality DNA templates to be carried out successfully. While it has been possible to readily produce large numbers of such templates from M13 or other single-stranded vectors for several years, the sequencing of double-stranded DNA templates using the ABI 373 DNA Sequencer has had a considerably lower success rate. We describe how the combination of a new fluorescent, dideoxy sequencing method, called cycle-sequencing, coupled with modifications to template isolation procedures based on Qiagen columns, makes fluorescent sequencing of double-stranded templates a reliable procedure. From a single five milliliter culture enough DNA can be isolated (up to 20 micrograms) to do 4-8 sequencing reactions, each of which yields 400-500 bases of high quality sequence data. These procedures make the routine use of double-stranded DNA templates a viable strategy in automated DNA sequencing projects.

Base Sequence↗
PubMed1991

Changes in beta 1- and beta 2-adrenergic receptor mRNA levels in brown adipose tissue and heart of hypothyroid rats.

The aim of the present work was to study the effect of hypothyroidism on the expression of the beta-adrenergic receptor (beta-AR) in interscapular brown adipose tissue and heart. The total density of plasma membrane beta-AR per tissue is decreased by 44% in hypothyroid rat interscapular brown adipose tissue and by 55% in hypothyroid rat heart compared with euthyroid controls. The effects of hypothyroidism on the density of both beta 1- and beta 2-AR subtypes were also determined in competition displacement experiments. The densities of beta 1- and beta 2-AR per tissue are decreased by 50% and 48% respectively in interscapular brown adipose tissue and by 52% and 54% in the heart. Northern blot analysis of poly(A)+ RNA from hypothyroid rat interscapular brown adipose tissue demonstrated that the levels of beta 1- and beta 2-AR mRNA per tissue are decreased by 73% and 58% respectively, whereas in hypothyroid heart, only the beta 1-AR mRNA is decreased, by 43%. The effect of hypothyroidism on the beta 1-AR mRNA is significantly more marked in the interscapular brown adipose tissue than in the heart. These results indicate that beta-AR mRNA levels are differentially regulated in rat interscapular brown adipose tissue and heart, and suggest that the decrease in beta-AR number in interscapular brown adipose tissue and heart of hypothyroid animals may in part be explained by a decreased steady-state level of beta-AR mRNA.

Adipose Tissue, Brown↗
PubMed1989

Xiaoke tea, a Chinese herbal treatment for diabetes mellitus.

Xiaoke tea, a traditional Chinese treatment for diabetes mellitus, lowered blood glucose concentrations in streptozotocin diabetic mice. To investigate Xiaoke clinically, a double-blind crossover study was undertaken in 12 non-insulin-treated diabetic patients. Xiaoke tea and ordinary tea (infusion of 2.72 g, 4 times daily) were consumed in random order for 4 weeks. A standard breakfast meal was taken before and after each treatment period. Xiaoke did not significantly affect glycosylated haemoglobin, basal or post-breakfast serum glucose and insulin concentrations, intermediary metabolite concentrations, triglyceride and cholesterol. No adverse side-effects of Xiaoke were evident.

Blood Glucose↗
PubMed1988

Diuretics and hyperkalaemia in diabetic ketoacidosis.

Diabetic ketoacidosis (DKA) often presents with hyperkalaemia. We investigated whether it was more likely in patients taking potassium-retaining diuretics. A retrospective survey of all patients (552 cases) presenting in DKA between 1974 and 1984 was undertaken. Initial biochemical data were compared for patients recorded as taking potassium-retaining diuretics (7 cases) at the time of presentation with those taking potassium-losing diuretics (13 cases), and age matched control groups were selected from those who presented in DKA but were not taking diuretics. There was no significant difference in initial serum potassium levels between the diuretic treated groups. The serum sodium was higher in the control group than in the potassium losing group (p = 0.045) and the serum urea significantly lower (p = 0.045). We conclude that potassium-retaining diuretics do not predispose to hyperkalaemia in diabetic ketoacidosis.

Adult↗
PubMed1988

Low affinity antibody to rubella antigen in patients after rubella infection in utero.

As a measure of the affinity of antirubella antibody, the resistance of the antibody to elution was used by increasing concentration of ammonium thiocyanate. The term affinity index has been used to define the molarity of thiocyanate which leads to a reduction of 50% of the initial density. The serum from a group of patients with intrauterine rubella was compared with the serum from a group of deaf children, some of whom could have rubella, and a group of controls with antibody following natural infection. The results show that the affinity index of patients with rubella is significantly lower than that of controls. The other deaf patients span the range of indices of the rubella and control groups suggesting that a number of those children could have deafness caused by intrauterine rubella.

Adult↗
PubMed1987

Fine needle aspiration cytology in the management of euthyroid goitre.

The role of fine needle aspiration cytology was examined in a series of 115 euthyroid patients referred with thyroid enlargement presenting consecutively to a joint medical and surgical thyroid clinic from April 1985 to December 1986. Needle aspiration was performed at first clinic attendance and repeated two to six months later in 39 subjects. Patients were classified according to cytological features of the thyroid aspirate. A diagnosis of benign colloid goitre was made in 59 patients, lymphocytic thyroiditis in 11, thyroid cyst in 32 and in addition there were 13 reports of suspicious or malignant cytological features. Malignancy was confirmed histologically in six patients in this group and five more had follicular adenomata. There were two false positive reports of 'suspicious' cytological features. During a median period of observation of 11.4 months one false negative cytological diagnosis has emerged in a further patient with follicular adenoma. Accuracy in the diagnosis of thyroid neoplasia of 97 per cent has thus been achieved. Fine needle aspiration cytology has replaced isotope and ultrasound scanning in our practice. The number of 99mTc scans performed in the investigation of goitre fell from 77 in 1984 to three in 1986. Neoplastic tissue was removed at operation in 40 per cent of cases proceeding to surgery (20 subjects), compared with a predicted rate of 9.6 per cent if all solitary nodules had been removed. Aspiration cytology performed at first clinic attendance has led to improved selection of patients for surgery and hence economy in their management.

Adolescent↗
PubMed1986

Antibody avidity determination by ELISA using thiocyanate elution.

Antibody avidity of human anti-rubella antibodies has been determined using the chaotropic thiocyanate ion in ELISA assays. Independence of antibody level and affinity was shown and the pattern of post-vaccination antibody affinity established. A variation of the standard ELISA assay was developed where replicate wells containing antibody bound to antigens were exposed to increasing concentrations of the chaotropic thiocyanate ion. Resistance to thiocyanate elution was utilised as the measure of avidity and an index (affinity index) representing 50% of effective antibody binding was used to compare different sera. The interplate coefficient of variation for the affinity index was 12.6% whereas the intraplate coefficient of variation was 4.1%.

Antibodies, Viral↗
PubMed1986

Clinical characteristics and aetiological classification of insulin-dependent diabetes in the elderly.

In a prospective study of 195 newly-diagnosed diabetic patients aged 65 years or over, 80 (41.0 per cent) were treated initially by diet, 89 (45.6 per cent) by diet and oral hypoglycaemic agents, and 26 (13.3 per cent) by diet and insulin. Fifteen patients (7.7 per cent) died within a year of diagnosis. Of 26 patients treated with insulin, six died in the first year, 14 were successfully transferred to diet and oral agent treatment and six continued on insulin--two of whom failed to a trial of oral agents, two showed only a temporary response and two received no trial. A further nine patients were taking insulin 12 months after diagnosis because of no response (eight patients) or a transient response (one patient) only to oral agents. Age, percentage ideal body weight, history of acute onset, blood glucose, glycosylated haemoglobin, and random C-peptide concentration at diagnosis did not discriminate between patients requiring insulin at 12 months and those successfully treated without insulin. Patients who were insulin-dependent 12 months after diagnosis had an increased frequency of ketonuria at diagnosis and a previous medical history of endocrine disease. In insulin-dependent patients there was an increased frequency of HLA DR3 but not DR4 and an increased frequency of thyroid microsomal and gastric parietal cell antibodies but not islet cell antibodies. It is concluded that elderly newly-diagnosed diabetic patients who are treated at diagnosis with insulin are not necessarily insulin dependent and can be given a trial of oral agents with safety.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1979

Very pure porcine insulin in clinical practice.

In a one-year follow-up study the insulin dose in diabetic patients using very pure porcine insulin was compared with that in patients using conventional preparations. The dose of insulin used to obtain diabetic control was reduced by 7% in 108 patients treated solely with very pure porcine insulin from the start of insulin treatment when compared with 108 matched patients who had received conventional insulins. In 117 patients whose treatment had been changed from conventional bovine or bovine-porcine insulin to very pure porcine insulin the dose was reduced by 9%. A further 511 patients receiving conventional insulins were examined for local cutaneous or subcutaneous abnormalities at insulin injection sites. Lipoatrophy was found in 49 of these patients (10%), but not in patients using very pure porcine insulin. The results confirm that very pure porcine insulin reduces the insulin dose needed to maintain diabetic control and may resolve or prevent local reactions such as lipoatrophy. Long-term advantages in reduced antigenicity to insulin and contaminating peptides remain to be established.

Adolescent↗
PubMed1978

The effect of maintenance dialysis on lymphocyte function. II. Peritoneal dialysis.

Lymphocyte function, as assessed by PHA-stimulated DNA synthesis, was studied in chronic renal failure patients maintained by peritoneal dialysis. In contrast to patients on haemodialysis, peritoneal dialysis patients had normal lymphocyte responsiveness pre-dialysis. There was no deterioration in the post-peritoneal dialysis plasma's ability to support control lymphocyte responsiveness as occurred after haemodialysis. Plasma dilution and reconstitution studies indicated that haemodialysis depleted the patients' plasma of nutrients and also added toxins, but peritoneal dialysis had neither effect.

Adult↗
PubMed1978

The effect of maintenance dialysis on lymphocyte function. I. Haemodialysis.

The effect of haemodialysis on mitogen-stimulated lymphocyte DNA synthesis was determined in twenty-four uraemic patients. Lymphocytes pre-haemodialysis were significantly less responsive to phytohaemagglutinin (PHA) than were control lymphocytes and showed the same degree of impairment as uraemic lymphocytes. Intrinsic lymphocyte responsiveness improved immediately after each haemodialysis. Pre-haemodialysis plasma inhibited control lymphocyte responsiveness and this inhibition was even greater in post-haemodialysis plasma. This effect of haemodialysis on plasma lasted for 4--8 hr. Similar alterations of response were noted, despite the use of different dialysers and also when two other mitogens were substituted for PHA. This deleterious effect of haemodialysis on lymphocyte function is important for its possible immune consequences, and may indicate a deficiency in current haemodialysis technique.

Adult↗
PubMed1976

Plasma inhibitors of lymphocyte response to phytohaemagglutinin in children with recurrent infections.

A survey of the immunological status of 175 children with recurrent infections showed that the plasmas of fifteen patients contained an inhibitor of lymphocyte response to phytohaemagglutinin (PHA). The inhibitors could be subdivided into two groups. One type of inhibitor acted only on the patients' lymphocytes (autologous-only). The other type also inhibited the response of control lymphocytes to PHA and in the mixed lymphocyte reaction (homologous). Plasma inhibitors of both types inhibit the response of rabbit lymphocytes to PHA. Patients with a plasma inhibitor frequently have a raised resting lymphocyte DNA synthesis.

Animals↗