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Biomedical subjects

M Mason

Publications and source records attributed to M Mason.

At least 37 records · Page 2Linked to original sources
PubMed1995

The isolation of Campylobacter jejuni from contaminated surfaces and its survival in diluents.

The isolation rates of campylobacters from contaminated surfaces were improved if swabs were placed directly into selective media rather than being stored in diluents before culture. Storage in diluents resulted in a loss of viability and the remaining viable campylobacter cells were often sub-lethally injured which sensitised them to selective agents in culture media and reduced isolation rates. Campylobacter jejuni, suspended in small drops of blood, was capable of prolonged survival on work surfaces if the drops remained liquid but the bacterium died rapidly once drops had dried.

Campylobacter jejuni↗
PubMed1995

Patients with TSH-secreting pituitary tumor possess different TSH molecular isoforms.

The objective of the study was to demonstrate if TSH secreted by a pituitary tumor correlates with particular molecular forms of TSH. Aliquots of sera from two hyperthyroid patients with TSH-secreting pituitary tumor were subjected to gel filtration chromatography to be assayed for TSH. The assay was repeated in one case after transsphenoidal adenomectomy. Sera from two additional patients with long-lasting primary hypothyroidism, and from two subjects with normal thyroid function were also chromatographed. Molecular weight (mol wt) of isoforms was calculated on a calibration curve obtained with molecular markers. The molecular variants were characterized on the basis of elution volume, mol wt, and partition coefficient. Chromatographic profile of the two cases with TSH-secreting pituitary tumor exhibited mainly two peaks of TSH immunoreactivity. The major component of immunoreactivity eluted as a peak corresponding with the alpha-subunit of the glycoprotein. This pattern was different from that obtained in sera from two women with hypothyroidism, which was heterogeneous and presented a predominance of molecular variants corresponding with mol wt of 22 and 29 kD, and no alpha-subunit was present. In cases of normal thyroid function the chromatographic profile showed that the major proportion of TSH eluted simultaneously with the labeled standard and 22 kD marker. These results demonstrate that TSH secreted by pituitary tumors is composed of various molecular forms and the alpha-subunit is the major component. This chromatographic profile is different from that observed in other cases with elevated concentrations of TSH as it occurs in primary hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A dosing scheme for carboplatin in adult cancer patients based upon pre-infusion renal function and platelet count.

The most important risk factors for the development of carboplatin-induced thrombocytopenia are total dose, glomerular filtration rate (GFR) and pre-infusion platelet count (P0). Pharmacokinetic and toxicity data from 23 patients with ovarian or testicular cancer were combined with published values from four other centers and the relationships between plasma clearance of ultrafilterable platinum and GFR, and between percentage reduction in platelet count and area under the plasma platinum curve were determined. The scatter in the data was estimated and used in a Monte-Carlo computer simulation to derive the following five-level dosing scheme. [table: see text] The scheme is based on 5% of patients incurring grade IV thrombocytopenia. Using this scheme, the majority of patients with ovarian or testicular cancer receiving carboplatin will be given an initial dose of 900 mg.

Adenocarcinoma↗
PubMed1994

Professional roles of dietitians: do dietitians and physicians agree?

In some quarters, dietitians and physicians do not agree on a role for dietetic practitioners. Dietitians seem to be more highly regarded, and their counsel is sought and advice heeded when both health professionals work on developing collegial relationships. Education matters: a course in nutrition for physicians-to-be and more depth in the sciences for dietetic students are major factors in establishing partnerships in patient care.

Attitude of Health Personnel↗
PubMed1994

Savings in hospital bed-days related to treatment with clozapine.

OBJECTIVE: The authors' aim was to determine whether clozapine was associated with a decrease in state hospital bed-days for patients with chronic schizophrenia. METHODS: Patients were started on clozapine in a state facility and were followed while taking the medication for 1.5 years (N = 172), two years (N = 86), and 2.5 years (N = 53). Patients' number of bed-days before starting clozapine was compared with those during the follow-up period. RESULTS: Bed-days were reduced by an average of 132 days per year after 1.5 years, 166 days per year after two years, and 201 days per year after 2.5 years (p < .001). During the final 180 days of each follow-up period, only 23 to 30 percent of patients were continuously hospitalized, compared with 56 to 64 percent before clozapine. Forty to 57 percent of patients had no hospital days at all during the last 180 days of follow-up. CONCLUSIONS: Based on hospital costs of $250 per patient per day, this reduction in bed-days could result in gross savings of about $33,000 per patient per year at 1.5 years, $41,500 per patient per year at two years, and $50,250 per patient per year at 2.5 years. Hospital patients are conspicuous targets for clozapine funding, since bed-days represent an easily measured expense. Nevertheless, community treatment should be an even higher priority, since most chronic mentally ill persons are outpatients.

Adult↗
PubMed1993

Distribution of growth hormone isoforms in sera from women with normal ovarian function, galactorrhea, and normoprolactinemia.

OBJECTIVE: To demonstrate if GH concentrations and molecular heterogeneity of GH correlates with the presence of galactorrhea in normoprolactinemic women with normal ovarian function. DESIGN: Aliquots of sera from women with normal ovarian function and normoprolactinemic galactorrhea were subjected to gel filtration chromatography, and the fractions were assayed for GH by the use of radioimmunoassay. Molecular weight of isoforms was calculated on a calibration curve obtained with molecular markers. The molecular variants were characterized on the basis of elution volume, molecular weight (MW), and partition coefficient. RESULTS: Basal serum GH levels were moderately elevated in all six normoprolactinemic women exhibiting galactorrhea. Chromatographic study of sera from these normoprolactinemic women showed the predominance of 40 to 50 kd molecular forms of GH as well as some very low MW GH isoforms. This pattern was different from that obtained in sera from normal women without galactorrhea who presented a predominance of heavier (> 60 kd) isoforms eluted before the GH labeled standard. The monomeric forms were present in less proportion but there was no significant difference as compared with galactorrheic group. CONCLUSIONS: Our investigation demonstrated elevated GH basal serum levels is normoprolactinemic women with galactorrhea, and chromatography in gel showed a low proportion of the large MW GH variants associated with a higher proportion of the dimeric forms and very low MW forms of GH. This is different from normal women without galactorrhea who had a predominance of heavier MW GH variants and lesser proportion of < 16 kd isoforms. It is concluded that an increased GH secretion may be responsible for abnormal lactation despite normal PRL levels in some women with normal ovarian function.

Adult↗
PubMed1993

A 1-y trial of the effect of high-selenium bread on selenium concentrations in blood and toenails.

The concentration of selenium in toenail clippings and blood reflects dietary intake better than does intake calculated from dietary data because of the highly variable selenium concentration in different samples of the same food. However, the time course of selenium intake in relation to subsequent concentrations in toenail clippings is unclear. Therefore, 12 males were fed high-dose (4.91 mumol Se/d), medium-dose (2.61 mumol Se/d), or control (0.41 mumol Se/d) whole-wheat-bread for 1 y and the concentration of selenium was measured in toenail clippings collected every 12 wk for 2 y. Toenail selenium concentration was unaffected by dietary intake in the previous 3 mo and appeared to provide a time-integrated measure of intake over a period of 26-52 wk. Use of selenium concentration in toenail clippings may be an alternative to blood when a measure of long-term average intake is desired. The absence of a short-term effect of diet on toenail selenium concentration also makes this a useful marker of intake in retrospective studies.

Adult↗
PubMed1992

Risk of second brain tumour after conservative surgery and radiotherapy for pituitary adenoma.

OBJECTIVE: To assess the risk of second brain tumour in patients with pituitary adenoma treated with conservative surgery and external beam radiotherapy. DESIGN: Long term follow up of a cohort of patients with pituitary adenoma and comparison of tumour occurrence with population incidence rates. SETTING: The Royal Marsden Hospital. SUBJECTS: 334 patients with pituitary adenoma treated with conservative surgery and radiotherapy (median dose 45 Gy) and followed up for 3760 person years. MAIN OUTCOME MEASURES: Second intracranial tumour and systemic malignancy. RESULTS: Five patients developed a second brain tumour: two had astrocytoma, two meningioma, and one meningeal sarcoma. The cumulative risk of developing a second brain tumour over the first 10 years after treatment was 1.3% (95% confidence interval 0.4% to 3.9%) and over 20 years 1.9% (0.7% to 5.0%). The relative risk of a second brain tumour compared with the incidence in the normal population was 9.38 (3.05 to 21.89). There was no excess risk of any other type of second primary malignancy. CONCLUSIONS: There is an increased risk of second intracranial tumour in patients with pituitary adenoma treated with surgery and radiotherapy. Although radiation is likely to be the most important factor contributing to the excess risk, further study is required in a cohort of similar patients not receiving radiation.

Adenoma↗
PubMed1992

The activity of single-agent carboplatin in advanced seminoma.

Between 1982 and 1990, 70 patients with advanced metastatic seminoma were treated with 4-6 courses of single-agent carboplatin (SAC) administered at 400 mg/m2 every 3-4 weeks. Treatment was of low toxicity and no patients suffered neurotoxicity, ototoxicity or significant renal damage. There was only one episode of neutropenic sepsis and no thrombocytopenic bleeding. The median follow-up of surviving patients was 3 years. 16 patients have relapsed and 4 of these 16 have died, thus the actuarial 3-year relapse-free survival was 77% (95% CI 65-86%), cause-specific survival was 94% (95% CI 82-99%) and overall survival was 91% (95% CI 80-96%). The risk of relapse was reduced by post-chemotherapy irradiation (PCRT) to involved nodes, occurring in 1/20 patients treated with PCRT compared with 11/31 who could have been treated but were not (P = 0.04). Of the 16 patients who relapsed, 12(75%) have been salvaged with combination chemotherapy and remain free from further relapse with a median follow-up of 18 months. Though this level of survival is equivalent to that obtained with initial cisplatin-based combination chemotherapy, the recurrence rate indicates that SAC remains an investigative treatment, except for unfit patients.

Adult↗
PubMed1992

Distribution of follicle-stimulating hormone and luteinizing hormone isoforms in sera from women with primary ovarian failure compared with that of normal reproductive and postmenopausal women.

OBJECTIVE: To demonstrate if molecular heterogeneity of gonadotropins correlates with the type of primary gonadal failure. DESIGN AND METHODS: Aliquots of sera from women with hypogonadism were subjected to gel filtration chromatography to be assayed for follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by the use of radioimmunoassay. Molecular weight (MW) of isoforms was calculated on a calibration curve obtained with molecular markers. The molecular variants were characterized on the basis of elution volume, MW, and partition coefficient. RESULTS: Chromatographic profile of sera from four women with natural menopause exhibited two FSH peaks of immunoreactivity and a heavier LH isoform. This pattern was different from that obtained in sera from women of reproductive age who presented a single peak that eluted after the corresponding standard. In six cases of idiopathic premature menopause and three more with gonadotropin-resistant ovary, the chromatographic profile showed a marked and remarkable molecular heterogeneity, particularly LH, and this was more apparent in women with resistant ovary. CONCLUSIONS: Our investigation confirms the relationship between the gonadotropin heterogeneity with the gonadal failure. The duration of the ovarian failure may influence the molecular proportion of gonadotropins and the predominance of heavier MW isohormones.

Adult↗
PubMed1992

Intra-arterial adriamycin, conventionally fractionated radiotherapy and conservative surgery for soft tissue sarcomas.

Thirteen patients with soft tissue sarcomas were treated with a combination of intra-arterial Adriamycin, conventionally fractionated radiotherapy (2 Gy per day), and conservative surgery (trimodal therapy). Severe acute complications occurred in 10 patients: 3 brachial artery thromboses, 6 delayed wound healing, 4 wound infections, and 3 cases of necrosis of the skin plus subcutaneous tissues. Three patients have developed local recurrence. Five patients are alive, 4 of whom are disease-free, and the median follow up time of surviving patients is 56 months. One has significant impairment of limb function due to joint ankylosis. An additional 2 patients were treated with intra-arterial Adriamycin and conservative surgery for local recurrence after previous surgery and radiotherapy; both died of subsequent metastatic disease, one having a further local recurrence. One patient with multifocal angiosarcoma was treated with intra-arterial Adriamycin and radiotherapy but no surgery, and is alive free of disease 49 months later. The combination of radiotherapy and intra-arterial Adriamycin with surgery resulted in significant acute toxicity. This small study has not demonstrated any improvement in local control compared with that expected with conservative surgery and radiotherapy alone.

Adult↗