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Biomedical subjects

R Freeman

Publications and source records attributed to R Freeman.

At least 325 records · Page 18Linked to original sources
PubMed1983

Electron microscopy of frozen hydrated sections of vitreous ice and vitrified biological samples.

The preparation and high resolution observation of frozen hydrated thin sections has been studied by transmission electron microscopy (TEM and STEM) on model systems, including pure water, protein solutions, catalase crystals, myelin sheath and various tissues. The state of the ice is determined by electron diffraction. Mass measurement in the electron microscope is used to determine section thickness and control hydration. An adequate depth of vitrified material for sectioning can be obtained from many biological suspensions or untreated tissues. Frozen hydrated sections around 100 nm thick can be produced under optimal conditions from vitreous ice or from vitrified biological samples. Sectioning, transfer and observation in the electron microscope is feasible without alteration of the sample hydration or its initial vitrification. Biological structures can be preserved and observed down to 10 nm. Under favourable working conditions, specimen compression during sectioning and electron beam damage are the factors limiting high resolution observations.

Animals↗
PubMed1983

Serum thyroid hormone levels in patients on continuous ambulatory peritoneal dialysis and regular hemodialysis.

In vitro thyroid function tests were performed on clinically euthyroid patients undergoing regular hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). The mean serum total thyroxine (TT4) and total triiodothyronine (TT3) values measured before HD were significantly subnormal. Similarly, CAPD subjects had reduced TT3 concentrations with low normal TT4 levels. Free thyroxine measurements, estimated by two different methods were aberrant in CAPD patients. Low normal reverse triiodothyronine (rT3) values were found in HD, in contrast to high normal rT3 levels in CAPD. Thyroid stimulating hormone determinations were normal, corresponding with the euthyroid status in both patient groups.

Adult↗
PubMed1983

Plasma oxytocin concentrations in a pregnant woman with total vasopressin deficiency.

Plasma concentrations of oxytocin and vasopressin were determined by radioimmunoassay in a woman with clinical diabetes insipidus. Plasma oxytocin levels were normal and ranged from less than 0.25 microU/ml to 76 microU/ml during the last month of pregnancy and during spontaneous labor. Vasopressin requirements did not change during pregnancy. Unexplained vasopressin resistance and massive diuresis occurred early in the postpartum period. Plasma vasopressin concentrations were undetectable in the nonpregnant state. The documentation of normal oxytocin production and total vasopressin deficiency suggests that an anatomic defect is unlikely to cause this disorder unless it is limited to axons and cell bodies containing vasopressin and not oxytocin.

Adult↗
PubMed1982

Replanning of an intensive therapy unit.

Considerable effort is needed when replanning an intensive therapy unit to avoid repeating mistakes in design, such as lack of windows and an impractical working area. Early consultation with the nursing and medical staff primarily responsible for such a unit is essential. The considerable technological innovations in intensive care will require flexibility in the future if they are to be incorporated into existing facilities.

England↗
PubMed1982

Pyogenic arthritis due to bacteroides complicating rheumatoid arthritis.

Two cases of anaerobic, pyogenic arthritis complicating rheumatoid disease due to bacteroides are described. The relative well-being of the patients and indolence of the affected joints are emphasised, and the effective role of metronidazole in the treatment of septic arthritis due to bacteroides is discussed.

Aged↗
PubMed1982

Angiodysplasias of the colon.

We studied 14 large bowel resections from patients with a provisional clinical diagnosis of a bleeding vascular lesion of the colon. For the purpose of this study we developed a barium-gelatine vascular injection technique. Six of the 14 cases were proven to be angiodysplasias with an identifiable mucosal vascular ectasia. The pathological findings in these six cases are described. We conclude that angiodysplasia represent a significant cause of lower gastrointestinal haemorrhage in the elderly. It is our opinion that only the mucosa vascular ectasia seen in these cases is histologically diagnostic and that sub-mucosal venous ectasia, while characteristic of angiodysplasia, is non-specific. the differential diagnostic features which will allow the histological distinction of angiodysplasia from other vascular lesions of the colon are discussed.

Aged↗
PubMed1982

Acquisition, spread, and control of Pseudomonas aeruginosa in a cardiothoracic intensive care unit.

The isolation rate and spread of infection and colonisation with Pseudomonas aeruginosa in a cardiothoracic intensive care unit was studied over two and a half years. The overall acquisition rate was low (2.68%) and was concentrated in the group of patients undergoing prolonged intensive care (over seven days). Although some cross-infection from long-stay to short-stay patients occurred in 1978 and 1979, when cubicle isolation was inadequate, acquisition of Ps aeruginosa was confined to the long-stay group when isolation facilities became sufficient. Further study of the long-stay patients disclosed two factors--use of broad-spectrum antibiotics and tracheostomy--significantly associated with acquisition of Ps aeruginosa. The possible uses of the results obtained and the particular relevance of a policy of narrow-spectrum chemoprophylaxis for open-heart surgery are discussed.

Anti-Bacterial Agents↗
PubMed1982

Addition of sodium metabisulphite to left atrial catheter infusates as a means of preventing bacterial colonisation of the catheter tip.

Sodium metabisulphite (SMBS) was added at a concentration of 0.05% to the dextrose-heparin solution used to flush left atrial catheters in one group of open-heart surgery patients. Two other groups of patients had left atrial catheters flushed with dextrose-heparin alone. Comparison of the isolation rate of organisms from the tips of the catheters in the three groups showed that the addition of SMBS significantly reduced bacterial contamination in the lines (two isolations from 36 catheters with SMBS added, compared with 13 from 56 and 15 from 65 in the other groups--that is, 5.55% compared with 23.2% and 23.1%). The protective effect of the SMBS was particularly evident in the first 48 hours after catheter insertion. No haematological or biochemical insult was found.

Adult↗