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Biomedical subjects

S Mather

Publications and source records attributed to S Mather.

At least 19 recordsLinked to original sources

Radiolabelling of peptides for diagnosis and therapy of non-oncological diseases.

Radiolabelled peptides have significant potential as radiopharmaceuticals for the diagnosis and therapy of receptor-expressing diseases. Methods have been developed for labelling peptides with a variety of radionuclides having a broad range of chemical and physical properties. These methods include both direct (where the radionuclide is bound directly to one or more atoms of the peptide structure) and indirect techniques in which bifunctional coupling agents are employed. Although most commonly applied to date in the field of oncology, a significant number of applications in non-oncological diseases have also been proposed and these can be expected to expand as the technology progresses. An overview is presented of some peptide-receptor systems in radiopharmaceutical development and the techniques which have been employed to radiolabel these peptides with isotopes of iodine, yttrium, indium, gallium, copper and technetium. While many of the examples employed are derived from cancer related indications, identical radiopharmaceutical chemistry can also be applied to peptides with applications in the fields of immunology, infection and other inflammatory conditions.

Binding Sites↗

Synergistic effects of nateglinide and meal administration on insulin secretion in patients with type 2 diabetes mellitus.

This study assessed the synergistic effects of nateglinide (a non-sulfonylurea D-phenylalanine derivative) and meals on insulin secretion in 24 patients with type 2 diabetes. Oral doses of 60 and 180 mg or 120 and 240 mg were administered to two cohorts of subjects 10 min before meals (or fasting) three times daily for 7 days, with washout intervals between treatment periods. Dose-dependent increases in plasma insulin occurred, with the peak effect within 2 h after treatment. Significantly greater insulin secretion was observed when nateglinide was taken before a meal compared to nateglinide given in the fasted state or in response to just the meal. Nateglinide lowered plasma glucose concentrations significantly vs. placebo at all doses, and doses of 120 and 240 mg were more effective than 60 mg (P < 0.05). Adverse event rates were similar for nateglinide and placebo, and no hypoglycemic episodes or serious adverse events were reported during the study. Nateglinide (120 mg) was the maximum effective dose in this study and was shown to be a safe and well tolerated therapy for control of mealtime glucose excursions in patients with type 2 diabetes. Results indicate that a synergistic interaction occurs between nateglinide and elevated mealtime plasma glucose concentrations to stimulate insulin secretion.

Adult↗

Service learning: a strategy for conducting a health needs assessment of the homeless.

An agency providing health care services for homeless persons and a nursing department at a liberal arts college established a service-learning partnership to complete a health needs assessment of homeless persons. Under the guidance of agency staff and a nursing faculty member, seven nursing students surveyed shelter residents (n = 101) in four urban shelters and conducted a focus group to identify residents' perceptions of health, health care needs, and health care service delivery. The service-learning partnership expanded the agency's services by providing research consultation and data collection that resulted in recommendations to improve health care services for the homeless. The agency contributed to the education of health professionals by providing students with a meaningful community service experience.

Adolescent↗

Comparison of plain radiographs and CT scans in instrumented posterior lumbar interbody fusion.

The success of posterior lumbar interbody fusion has been analyzed primarily by plain radiography. There are no widely accepted criteria for fusion, except for lack of motion, which can be obviated by instrumentation, and the appearance of continuous bridging bone in the interspace. To determine the accuracy of plain radiography in detecting posterior lumbar interbody union, the radiographs of instrumented posterior lumbar fusion performed at 22 levels were compared with reformatted computed tomography (CT) scans. Results revealed that although 17 of 22 interbody levels were classified as fused by radiograph, 10 of these 17 demonstrated a nonunion by reformatted CT scans taken an average of 13.8 months postoperatively. Only progressively increased density by radiograph correlated with a solid fusion by CT scan. We therefore conclude that plain radiographs are unreliable in reporting the results of posterior lumbar interbody fusion and that CT scanning may be more appropriate.

Adult↗

Women in the Persian Gulf War: health care implications for active duty troops and veterans.

The health of women who participated in Operations Desert Shield/Storm was evaluated to better understand the medical requirements of deployed military women and women veterans of the Persian Gulf War. Women's health care needs during the Persian Gulf War were reported to be very similar to those of men, with the exception of gynecologic problems, which generally were not serious and did not require hospitalization. However, insufficient data were obtained to identify specific health care needs among deployed women troops. During the 5 years since the end of the Persian Gulf War, no unique health problems have been identified among women veterans. Whether there will be any exceptional long-term health care requirements currently is unknown. Nevertheless, important medical problems of all women-reproductive issues, menopause, osteoporosis, joint disease, breast cancer, heart disease, and stroke-inevitably will be major considerations when caring for this population of war veterans.

Adult↗

Immediate and delayed contact hypersensitivity to verbena plants.

Plants from the Verbenaceae family may cause contact dermatitis of unknown nature. This report describes 2 cases of allergic reactions to the Verbena species. A teenage boy developed an anaphylactic allergic response following contact with the leaves of Verbena hybrida. Characterization of the patient's specific IgE response to Verbena hybrida, using Western blots and autoradiography, identified the specific 62000 Dalton allergen present in the verbena leaves to which the patient reacted. This is the first report of an IgE-mediated immediate contact hypersensitivity reaction to Verbena hybrida, a common perennial in South African gardens. The other case was a 23-year-old female gardener who developed immediate and delayed-type contact dermatitis from Verbena elegans 'Cleopatra' produced in a Danish nursery. Prick tests to plant material were considered positive and of an allergic nature.

Adolescent↗

Hepatic ultrasound findings in the glycogen storage diseases.

Hepatic ultrasonography was performed on 70 patients with the hepatic glycogen storage diseases (GSDs) to assess parenchymal echogenicity. 27 patients had GSD-I, 24 had GSD-III and 19 had GSDs-VI/IX; ages varied from 0.6 to 35.7 years (median 11.7). 31 (44%) had normal or mild parenchymal changes, and 41% (11/27) of those with GSD-I, 25% (6/24) with GSD-III and 11% (2/19) with GSDs-VI/IX had marked changes. No relationships were found between the ultrasonographic appearances and other indices of metabolic control, including plasma triglycerides, total cholesterol or height standard deviation score. Seven adult patients (21-29 years) were found to have hepatic tumours: six with GSD-I and one with GSD-III. Those with GSD-I and tumours tended to have the more severe hepatic parenchymal changes. We conclude that ultrasonography may be useful in identifying patients with GSD-I at risk of hepatic tumour formation.

Adenoma↗

IgE specific immune responses to an African grass (Kikuyu, Pennisetum clandestinum)

Kikuyu grass (Pennisetum clandestinum) is widely used as a grazing pasture in Africa and, although it is extensively cultivated as a lawn for sports fields and domestic gardens, its allergenicity has never been studied in vitro. Using an extract of Kikuyu grass pollen, polyacrylamide gel electrophoresis, Western blotting and a monoclonal anti-human IgE antibody, the specific IgE binding, in the serum of 160 allergic and non-allergic patients in the Cape Town area, to a Kikuyu grass extract was studied. IgE in the sera of 43/104 known grass-allergic individuals bound to Kikuyu grass on the Western blots. In addition, 4/28 'non-allergic' control subjects were found to have Kikuyu grass-specific IgE. Five different profiles of specific IgE reactivity to Kikuyu grass antigens were observed. In 29/43 patients, IgE bound to two dominant 48 and 70 kD allergens in the Kikuyu extract. Although a degree of cross-reactivity with Bermuda grass (Cynodon dactylis) was found in immunoabsorption studies, the 48 and 70 kD allergens appear to be unique to Kikuyu grass. Exposure of heparinized blood from Kikuyu grass-positive patients to the Kikuyu extract stimulated the release of histamine from their basophils in vitro. Kikuyu grass pollen is thus identified as an important aero-allergen in South Africa.

Allergens↗

Pseudotumoral cystitis in children: a review of the ultrasound features in four cases.

Pseudotumoral cystitis is an uncommon inflammatory condition which may masquerade as a bladder tumour in children. There are a variety of clinical presentations such as haematuria, dysuria, infection and obstruction. Reported causative factors include infection (bacterial, fungal and parasitic) and allergy. Ultrasound is an excellent imaging modality for demonstrating this intravesical lesion although the spectrum of features is poorly described in the literature. We report our recent experience of four patients with pseudotumoral cystitis and describe the clinical features and ultrasound appearance of this condition in children.

Child↗

A scintigraphic comparison of iodine-123-metaiodobenzylguanidine and an iodine-labeled somatostatin analog (Tyr-3-octreotide) in metastatic carcinoid tumors.

A number of neoplasms are known to express somatostatin receptors, and the use of somatostatin receptor imaging in their localization has recently been described. We compared an 123I-labeled somatostatin analog Tyr-3-octreotide (TOCT) and 123I-labeled metaiodobenzylguanidine (MIBG) scintigraphy in seven patients with histologically proven metastatic carcinoid tumors. The optimum time for identifying tumor uptake on scanning after [123I]MIBG was 24-48 hr, and after 123I-TOCT 10-30 min postinjection. Both radiopharmaceuticals showed a varying spectrum of tracer uptake ([123I]MIBG showed no uptake in one patient; minimal in two; moderate in two; and intense in two; 123I-TOCT showed no uptake in two patients; minimal uptake in one; moderate uptake in two; and intense uptake in two). In two patients, 123I-TOCT identified metastatic lesions not seen by [123I]MIBG scintigraphy. These preliminary results suggest that [123I]MIBG and 123I-TOCT are useful and complementary imaging techniques for detecting metastatic carcinoid tumors.

3-Iodobenzylguanidine↗

A PAC study of the binding of 111In to a monoclonal antibody via the macrocyclic molecule 1,4,7-triazacyclononanetriacetic acid.

Time integral and time differential PAC measurements have been made from samples of 111In bound to the functionalized 9N3 macrocycle, and 111In bound to the monoclonal antibody AUA1 via the macrocycle, over the temperature range 80-350 K. Values obtained for the integrated perturbation coefficient G22 (infinity) clearly illustrate the effects which the antibody has on the angular correlation of the gamma-rays emitted by the 111In decay. Measurements of the quadrupole frequency in the 111In-9N3-AUA1 samples show a transition temperature between 250 and 275 K which was not detected in the 111In-9N3. An arrhenius plot of the temperature dependence of the correlation time for the 111In-9N3 yielded a value of 0.10 +/- 0.01 eV for the activation energy associated with molecular re-orientation, whilst a Debye plot indicated an effective volume of (10 +/- 1) x 10(-27) m3 for the same sample. Extrapolation of the Debye plot suggests a high relaxation constant which may be attributed to internal vibrational modes in the macrocycle. Comparisons are made with similar work on the plasma protein transferrin.

Antibodies, Monoclonal↗