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Biomedical subjects

A Taylor

Publications and source records attributed to A Taylor.

At least 829 records · Page 46Linked to original sources
PubMed1977

The syndrome of inappropriate antidiuretic hormone secretion as a cause of hyponatremia in cystic fibrosis.

The syndrome of inappropriate secretion of antidiuretic hormone was observed in two patients with cystic fibrosis during acute exacerbation of chronic pulmonary disease. It was diagnosed by the accepted clinical and laboratory criteria and confirmed in one case by values for immunoreactive vasopressin that were inappropriately high for plasma osmolality. The severe hyponatremia was corrected by fluid restriction, alone or combined with intravenous treatment with diuretic and hypertonic saline solution. In addition, there was simultaneous therapy of the pulmonary disease. SIADH thus must be added to salt loss as a cause of hyponatremia in CF, and may be more common than realized in patients with CF and severe pulmonary disease.

Adult↗
PubMed1977

99mtechnetium penicillamine: a renal cortical scanning agent.

99mTechnetium penicillamine, a renal cortical imaging agent, can be used to provide a rapid, safe and non-invasive assessment of renal morphology and the renal vascular supply. Since this agent is not excreted significantly during the imaging procedure cortical scans of high quality can be obtained without image deterioration owing to a superimposed collecting system. These scans, which are clearly superior in anatomical detail to earlier scans using 131I hippuran, can be obtained along with the 131I hippuran renogram when the patient comes to the nuclear medicine department. Herein we demonstrate the anatomical detail it is now possible to achieve by presenting the cortical renal scans and accompanying radiograms from 5 patients with different renal pathology.

Adenocarcinoma↗
PubMed1977

The effect on fungal growth of some 2,5-dihydroxy-1,4-benzoquinones.

It has been shown that 2,5-dihydroxy-1,4-benzoquinones decrease vegetative growth and inhibit spore germination of 12 species of fungi belonging to six diverse genera. The nature of are substituents at the 3 and 6 positions of the quinone ring also affected their growth-inhibitory properties; generally those substituents of lower polarity inhibited growth at lower concentrations. As in the case of cochiliodinol, chemical modification of the quinone group, or the hydroxyl groups of the quinone ring, in compounds of the polyporic acid series, also led to loss of biological activity.

Antifungal Agents↗
PubMed1977

Noninvasive determination of glomerular filtration rate using x-ray fluorescence.

Accurate glomerular filtration rates (GFR) can be calculated based on the infusion of small amounts of nonradioactive iothalamate and collection of plasma samples for assay by x-ray fluorescence. This innovation permits frequent clearance determinations in patients without the hazard of repeated radiation exposure and without the necessity of catheterization of the bladder for urine samples. Thus, the technique becomes feasible in children, transplant patients, and other needing accurate and frequent GFR determinations.

Animals↗
PubMed1977

Diagnostic value of urine mercury measurements.

A review of referrals to a regional heavy metals centre for possible mercury poisoning was made. Samples were received either from subjects who were well but were known to have some contact with mercury or from patients with an illness under investigation but undiagnosed. The problems associated with diagnosis of mercury toxicity in the absence of known exposure are illustrated by two case reports.

Alkylmercury Compounds↗
PubMed1977

Bone scanning in osteolytic Paget's disease: case report.

Technetium-99m polyphosphate bone scans of three elderly patients with osteolytic Paget's disease are presented. Similar findings of increased accumulation of the tracer in the region of diseased bone, and even greater uptake at the advancing edge of osteolysis, are seen in both the skull and long bones. The reason for this scintigraphic pattern is postulated from histologic findings of osteolytic Paget's disease.

Aged↗
PubMed1977

Comparison of 131I-tetracycline and 67Ga-citrate as abscess localizing agents.

Previous studies have shown that radiolabeled tetracyclines tend to accumulate in infarcts and necrotic tumors. These results suggested that radiolabeled tetracyclines might also accumulate in necrotic abscesses or areas of inflammation. In order to develop a better abscess scanning agent, we compared the efficiency of 131I-tetracycline with 67Ga-citrate in labeling experimentally induced staphylococcal aureus abscesses in rats 24 and 72 hours after injection. In addition to evaluating 131I-tetracycline as an abscess scanning agent, we hoped to obtain data which might clarify the controversy regarding early versus late gallium scanning in suspected infection. 131I-tetracycline was chosen over 99mTc-tetracycline because the longer half-life of 131I would allow 72 hour imaging. Absolute concentrations of gallium in the abscess contents and in the surrounding areas of inflammation were significantly greater than the concentration of 131I-tetracycline at both 24 and 72 hours. With the exception of blood, muscle, and bone, the abscess-to-tissue activity ratios for gallium and 131I-tetracycline were similar; however, the ratio of gallium activity in the inflammed tissue to other tissues was greater than that of 131I-tetracycline for every tissue examined at both time periods. The data suggest that 131I-tetracycline has little potential as a general abscess scanning agent. The gallium tissue concentrations and tissue ratios suggest that abscesses which can be imaged at 72 hours can probably be imaged at 24 hours, thus allowing earlier initiation of appropriate therapy. Because of the higher lesion-to-blood ratio at 72 hours, a 72-hour scan would appear to be indicated before a scan is interpreted as normal.

Abscess↗
PubMed1976

The involvement of RNA in the initiation of DNA synthesis in mammalian cells. Artifacts arising during caesium-salt density-gradient centrifugation which simulate a covalent attachment of RNA to newly synthesized DNA.

Artifacts were encountered during caesium salt density gradient centrifugation which simulated results expected if newly synthesized DNA is covalently attached to RNA. Newly synthesized DNA (in baby hamster kidney cells, BHK-21/C13), pulse-labelled with [3H]thymidine for 10 min at temperatures below 25 degrees C, banded at a greater buoyant density than mature [14C]DNA (heat-denatured nucleic acids) when centrifuged to equilibrium in caesium chloride gradients. Some of the newly synthesized RNA, labelled with [3H]uridine, banded at a buoyant density slightly greater than DNA in caesium sulphate gradients. These results were not obtained when nucleic acids were pulse-labelled at 37 degrees C, nor when samples were heat-denatured in the presence of formaldehyde. This suggests that nucleic acids can aggregate during centrifugation; this is discussed in relation to the molecular size of the DNA.

Cell Line↗
PubMed1976

Morphogenic effects of alpha-factor on Saccharomyces cerevisiae a cells.

Saccharomyces cerevisiae mating type a cells enlarged and elongated when exposed to alpha-factor, a sex pheromone produced by mating-type alpha cells. This morphogensis required exogenous-D-glucose, nitrogen, and phosphate, and cells in exponential phase responded better than stationary-phase cells. Morphogenesis was blocked by cycloheximide and by inhibitors of cell wall biosynthesis such as 2-deoxy-D-glucose, 2-deoxy-2-fluoro-D-glucose, and 2-deoxy-2-fluoro-D-mannose, but not by polyoxin D. One to two hours after addition of pheromone, a cells became more susceptible to lysis by glucanases, a change that was dependendent on the dose of alpha-factor and was blocked by drugs that block morphogenesis. On the other hand, treatment with alpha-factor did not increase susceptibility to attack by trypsin, subtilisin, or exo-alpha-mannanase. Radioactive label, incorporated into cell wall polysaccharides during treatment with alpha-factor, was not secreted into the medium during morphogenesis. Analysis of the labeled wall polymers showed that alpha-factor-treated cells contain more glucan and less mannan than control cells, and that the mannan of treated cells contains an increased proportion of shorter side chains and unsubstituted backbone mannose units. Thin-section electron microscopy of treated cells revealed that the cell wall possesses a diffuse outer layer in the extension and is thinner at the tip.

Animals↗
PubMed1976

Ventilation-perfusion lung images in the Swyer-James syndrome.

Ventilation-perfusion lung imaging appears to be a significant nonivasive means of supporting the clinical diagnosis of Swyer-James syndrome. Three cases are presented which display characteristic delayed washout of xenon from a small or normal-sized, underperfused hyperlucent lung.

Adult↗
PubMed1976

Analysis of muscle receptor connections by spike-triggered averaging. 1. Spindle primary and tendon organ afferents.

1. The synaptic connections of 44 single identified muscle spindle Ia afferents and of 21 Golgi tendon organ (Ib) afferents from medial gastrocnemius (MG) were studied in 46 cats by the spike-triggered averaging of synaptic noise in 803 motoneurons of various types. 2. The well-known monosynaptic Ia excitatory connections were confirmed and their characteristics examined in 113 cells. The method was used at greater sensitivity than before and revealed that, in addition to the larger EPSPs of the order of 300 muV, there were many below the previously reported lower 17-muV limit. 3. By studying the Ia disynaptic inhibitory pathway with quick stretch-evoked Ia volleys and by spike-triggered averaging (STA), it was shown that the latter method can reveal disynaptic and possibly trisynaptic excitatory connections. This is believed to depend on having continuous activity in the relevant interneurons. 4. Latencies of individual connections showed broad distributions and arguments are advanced for setting working limits to mono- and disynaptic paths for Ia excitation and inhibition. Monosynaptic EPSP latency from cord entry was 0.4-1.1 ms and disynaptic inhibition was 1.2-2.4 ms. It was recognized that the boundaries are not rigid and monosynaptic Ia EPSPs may have latencies up to 1.5 ms. 5. Rise times of disynaptic PSPs were, on average, significantly longer than monosynaptic, but individual disynaptic responses could have values within the monosynaptic range. 6. A small diphasic wave shortly preceding the monosynaptic EPSPs was interpreted as a presynaptic spike. Its timing was consistent with this and, as such, permitted estimates to be made of central conduction time. 7. An early negative wave (latency less than or equal 1.1 ms) of small emplitude was sometimes detected in antagonist motoneurons when triggering from Ia afferents. It was found tha extracellular fields could be detected due to single Ia afferent excitations and efforts were made to see if the early negative wave could be explained by this. In a few cases there was evidence that a very short-latency IPSP might be occuring. This evidence and its implications are discussed with attention to the new factors which have to be considered in using the spike-triggered averaging method at very high sensitivity. 8. Ib effect were di- or trisynaptic. They were excitatory to 18% of synergists and to 28% of antagonists. They were inhibitory to 41% of synergists and to 19% of antagonists. The Ib IPSPs were larger than the EPSPs.

Animals↗