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Biomedical subjects

S Hunt

Publications and source records attributed to S Hunt.

At least 19 recordsLinked to original sources
PubMed1991

Surgical face masks in modern operating rooms--a costly and unnecessary ritual?

Following the commissioning of a new suite of operating rooms air movement studies showed a flow of air away from the operating table towards the periphery of the room. Oral microbial flora dispersed by unmasked male and female volunteers standing one metre from the table failed to contaminate exposed settle plates placed on the table. The wearing of face masks by non-scrubbed staff working in an operating room with forced ventilation seems to be unnecessary.

Air Microbiology↗
PubMed1991

Transplant coronary artery disease: histopathologic correlations with angiographic morphology.

Accelerated coronary artery disease is a major cause of morbidity and mortality among cardiac transplant recipients. Ten patients who died or underwent retransplantation within 2 months of coronary angiography had direct correlation of angiographic (normal discrete lesions, diffuse concentric narrowing) with histologic appearance of coronary arteries. Of the 26 angiographically normal segments, 73% showed mild to moderate fibrous intimal thickening by light microscopy. The remainder had intermediate lesions or atheromatous plaques. Discrete stenoses usually corresponded to lipid-rich intermediate or atheromatous disease. In contrast, angiographically diffuse, concentrically narrowed lesions usually were areas of severe fibrous intimal thickening. Fresh or organizing thrombus was most often associated with discrete lesions and accounted for all complete occlusions. Histologic and angiographic comparisons of the degree of luminal narrowing showed generally good correlation for high grade stenoses. Lesions graded as having less than 25% diameter narrowing were often underestimated angiographically as compared with histologic determinations. Transplant coronary artery disease has a heterogeneous histologic and angiographic appearance, with angiographic underestimation of disease in some patients.

Adult↗
PubMed1991

Long-term results of cardiac transplantation.

Over 12,000 cardiac transplants have been performed worldwide and many recipients are alive between 10 and 20 years posttransplant. The results, complications, and pathology of the long-term survivors are discussed in this chapter.

Cardiomegaly↗
PubMed1991

The impact of screening sinus CT on the planning of functional endoscopic sinus surgery.

The clinical and radiologic records of 500 sequential patients who underwent screening sinus CT as a prelude to possible functional endoscopic sinus surgery (FESS) were reviewed in order to answer three clinical-radiologic questions: (1) Can distinct radiologic patterns of inflammatory disease be identified on screening sinus CT (SSCT)? (2) If so, what are these radiologic patterns? (3) How do the findings seen on SSCT influence the endoscopic surgical plan? Five basic radiologic patterns of sinonasal inflammatory disease were identified among the 500-member patient population. These were based on known patterns of mucociliary drainage correlated with obstructive patterns observed on the CT scans. These radiologic patterns included: (1) infundibular (129 of 500 or 26%), (2) ostiomeatal unit (126 of 500 or 25%), (3) sphenoethmoidal recess (32 of 500 or 6%), (4) sinonasal polyposis (49 of 500 or 10%), and (5) sporadia (unclassifiable) (121 of 500 or 24%) patterns. Normal SSCT was seen in 133 of the 500 patients (27%). Although the ostiomeatal unit is the central feature in sinonasal inflammatory disease, obstruction of the infundibulum alone or of the sphenoethmoidal recess can cause unique inflammatory patterns of disease that require tailored FESS. The identification of sinonasal polyposis raises a different set of FESS considerations. The sporadic pattern of inflammatory disease, when identified, creates unique FESS challenges, depending on the specific sinus or sinuses involved. Assignment of these patterns to the individual case also assists in patient management by grouping patients into nonsurgical (normal CT), routine (infundibular, ostiomeatal unit, and most sporadic patterns) and complex (sinonasal polyposis and sphenoethmoidal recess) surgical groups.

Acute Disease↗
PubMed1991

Effects of long term 2% fish oil supplements on tissue fatty acids, phospholipids, cholesterol, and arterial histology in Japanese quail (Coturnix coturnix japonica).

The effects of 2% olive oil (OO) or fish oil (FO) (Super epa500) dietary supplementation (9 months) on Japanese "SEA" quail was investigated. The animals were examined for tissue biochemical changes and possible blood vessel fatty deposition. The fatty acids of blood and tissue extracts from heart, liver and fat were analyzed by gas-chromatography/mass spectrometry. The ratio of arachidonic acid to eicosapentaenoic or docosahexaenoic acid was markedly decreased in FO treated animals compared to OO or control diet treated animals. Tissue cholesterol and total phospholipids were present in elevated amounts in the heart and liver of FO treated animals. After the 9-month regimen many animals had residual atherosclerotic lesions but the FO treated birds had considerably more fatty streaks and fatty deposition in their large vessels compared to control or OO treated animals. Although the lipid composition of tissues of FO treated animals would indicate that the purported cardioprotective omega-3 fatty acids are enriched in the various tissues examined compared to olive oil and control diet treated animals, the possible detrimental effect of saturated fat, cholesterol, or some other component of the fish oil preparations is suggested from the histological appearance of fatty deposition in the blood vessels (aortae) of these inbred animals. These results in quail are strikingly similar to that seen in the omega-3 FA treated WHHL rabbit (15).

Adipose Tissue↗
PubMed1990

Pharmacokinetics of oral acetyl-L-carnitine in renal impairment.

Acetyl-L-carnitine 1.5 g and 3.0 g was administered as three divided doses on each of two occasions to 24 people with varying renal failure (creatinine clearance 127-8 ml.min-1). Plasma and urinary concentrations of total-L-carnitine, free (non-esterified) carnitine, short-chain esters and acetyl-L-carnitine were measured. The baseline (pre-study) concentrations of all four substances were related to renal function. Patients whose creatinine clearance was below about 30-40 ml.min-1 were had the highest concentrations. Renal elimination of all four substances was related to dose and to renal function. There was evidence for dose-related elimination, with greater elimination of the larger dose.

Acetylcarnitine↗
PubMed1988

Retransplantation for severe accelerated coronary artery disease in heart transplant recipients.

Development of accelerated coronary artery disease (CAD) in the cardiac allograft is one of the major causes of late graft failure in heart transplant recipients. At the Stanford University Medical Center 356 heart transplant procedures were performed in 329 patients by the end of January 1985. Eighty-nine of these patients developed evidence of transplant CAD. Twenty retransplant procedures, including 2 third transplants, were performed in 19 of the 89 patients because of transplant CAD. The graft survival rates after the second transplant were 55%, 25% and 10% after 1, 2 and 5 years, respectively. Nine of these retransplant patients currently survive, the longest for 5.5 years. To examine potential risk factors for development of severe transplant CAD, these 20 retransplant procedures were compared with 113 transplant recipients who had no evidence of transplant CAD on annual coronary arteriograms. An excess of rejection episodes (3 +/- 2 vs 2 +/- 1 episodes/patient, p = 0.02), elevated total cholesterol (266 +/- 78 vs 225 +/- 47 mg/dl, p = 0.002) and higher low-density lipoprotein levels (176 +/- 88 vs 137 +/- 46 mg/dl, p = 0.009) were noted in the transplant CAD retransplant group. Five of 11 retransplant recipients who survived greater than 1 year again developed transplant CAD. Characteristic morphologic features and rapid progression of CAD in the second graft were similar to those in the primary graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Electron probe X-ray microanalysis of the composition of hyaline articular and non-articular cartilage in young and aged rats.

Blocks of articular cartilage were taken from tibiae of young adult (8 week) and aged adult (50-60 week) rats; xiphisternal cartilage was obtained from young adult rats. Specimens were quench-frozen in nitrogen slush, freeze-fractured and examined by low-temperature scanning electron microscopy. The results of X-ray microanalysis of frozen-hydrated bulk cartilage are semi-quantitative. The composition of chondrocyte nuclei and cytoplasm are only marginally different. Xiphisternal chondrocytes contain lipid inclusions which show an absence of element peaks and are designated as being neutral lipid. Intra- and extracellular Na, P, S, Cl, K and Ca count rates are significantly different. Cartilage from older rats contains more S and Ca, and less K and Cl in the intercellular matrix than that from young rats. Intracellular K levels are lower in aged than in young rats. The intercellular matrix of xiphisternal cartilage contains larger amounts of S, Na and K, and a smaller amount of Cl compared to that of tibial articular cartilage.

Aging↗
PubMed1988

Cation movement in rat articular and non-articular cartilage and in isolated chondrocytes: calcium influx and efflux.

1. Calcium ion influx varies between different types of young adult rat cartilage. Sternal cartilage accumulates significantly less Ca2+ than other cartilage types. 2. Influxes of Ca2+ into young adult and ageing tibial cartilage display no significant differences. 3. Efflux of Ca2+ from sternal and tibial cartilage resolves into exponential phases indicative of three compartments. Tracheal cartilage displays two compartment behaviour only. 4. Efflux of Ca2+ from isolated chondrocytes has different characteristics to cartilage efflux with the third slow compartment reduced. 5. Modification of Ca2+ efflux by lanthanum and barium is suggestive of an exchange of strongly bound extracellular calcium during the slow phase of the efflux from young adult tibial cartilage. 6. The metabolic inhibitor 2,4-dinitrophenol is without effect on the efflux of Ca2+ from tibial articular cartilage. 7. The degree of calcium binding exhibited during efflux depends upon cartilage type. Non-articular sternal cartilage binds calcium more strongly than articular tibial, both binding more strongly than non-articular tracheal cartilage. 8. In articular cartilage calcium binding shows an age-related increase.

2,4-Dinitrophenol↗
PubMed1986

Administration of MPTP to the common marmoset does not alter cortical cholinergic function.

The administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to common marmosets induced persistent motor deficits and decreased concentrations of dopamine, homovanillic acid, and 3,4-dihydroxy-phenylacetic acid (DOPAC) and [3H]dopamine uptake in the caudate-putamen. There was an 80% reduction in tyrosine hydroxylase immunoreactive cells in substantia nigra. At 10 days following the start of MPTP administration, the activity of choline acetyltransferase in the thalamus and frontal cortex was unchanged compared with control animals. Similarly, specific [3H]QNB binding was unaltered. At 4-6 weeks following the start of MPTP treatment, choline acetyltransferase activity and [3H]QNB binding in the frontal cortex and thalamus remained unaffected. There was no evidence for cell loss in the nucleus basalis of Meynert or alteration in the intensity of staining for acetylcholinesterase. MPTP treatment of the common marmoset produces a nigrostriatal lesion. In contrast, MPTP did not alter cortical cholinergic function and was not neurotoxic to the cholinergic cells in the nucleus basalis of Meynert.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1985

Severe illness caused by the products of bacterial metabolism in a child with a short gut.

An 8-year-old boy with a short gut had six episodes of metabolic acidosis and neurological dysfunction over a 1 month period. The neurological features consisted of a depressed conscious state, confusion, aggressive behaviour, slurred speech and ataxia. The organic acid profile of urine demonstrated increased amounts of lactic, 3-hydroxypropionic, 3-hydroxyisobutyric, 2-hydroxyisocaproic, phenyllactic, 4-hydroxyphenylacetic and 4-hydroxyphenyllactic acids. Of the lactic acid 99% was D-lactic acid. The anaerobic gut flora consisted almost entirely of Lactobacilli in unusually large numbers. A course of vancomycin prevented further episodes. A urinary organic acid profile may be diagnostic when a person with a short gut develops metabolic acidosis or an unusual encephalopathy and bacterial metabolites should be considered in other patients with unusual combinations of organic acids in the urine.

Acidosis↗
PubMed1985

The mechanisms of ventricular tachycardia in humans determined by intraoperative recording of the electrical activation sequence.

We recorded ventricular activation sequence during ventricular tachycardia in 76 patients who underwent surgical therapy of refractory ventricular tachycardia. Ventricular tachycardia arose from a discrete site (focal origination) in 28 patients (37%) or resulted from reentry around scar (macroreentry) in 22 patients (29%). The mechanism responsible for ventricular tachycardia was not discernable in the remaining 26 patients (34%), usually because of inadequacy of activation data. We conclude: (1) although focal originating of ventricular tachycardia is common, more frequently the mechanism is either macroreentry or uncertain, as assessed by conventional recording techniques; thus, a search for the "site of earliest activation" during ventricular tachycardia frequently may fail to direct rationally the operative procedure; (2) conventional techniques for intraoperative study of electrical activation during ventricular tachycardia are inadequate.

Cardiac Pacing, Artificial↗