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Biomedical subjects

S Talbot

Publications and source records attributed to S Talbot.

At least 19 recordsLinked to original sources

Coagulation-factor deficiencies and abnormal bleeding in Noonan's syndrome.

Noonan's syndrome is characterised by a dysmorphic facies, congenital heart disease, and short stature, and is inherited as an autosomal dominant trait. Because abnormal bleeding has also been reported, we investigated a group of patients for coagulation-factor deficits. Of the 72 individuals studied (37 male, 35 female, mean age 11.4 years), 47 (65%) had a history of abnormal bruising or bleeding. 29 patients (40%) had a prolonged activated partial thromboplastin time. Specific abnormalities in the intrinsic pathway of coagulation (partial factor XI:C, XII:C, and VIII:C deficiencies) were found in 36 patients (50%). Multiple abnormalities among these 36 patients included combined factor XI:C and XII:C deficiencies (4 patients) and factor XI:C and VIII:C deficiencies (4), and 1 patient had combined factor VIII:C, XI:C, and XII:C deficiency. There was poor correlation between a history of abnormal bleeding and coagulation-factor deficit. In five families, similar coagulation-factor deficiencies were present in first-degree relatives with the syndrome. The pattern of inherited bleeding abnormalities seen in Noonan's syndrome suggests autosomal regulation of the intrinsic coagulation pathway.

Adolescent

Pediatric poisoning from over-the-counter imidazoline-containing products.

We present two instructive cases of imidazoline poisoning in young children. Imidazoline decongestants, readily available in numerous non-prescription preparations, can rapidly produce toxicity from oral ingestion and topical application. Signs and symptoms depend on whether peripheral or central alpha 2-adrenergic receptor stimulation predominates. Timely diagnosis depends on a high index of suspicion and careful questioning about the availability of these over-the-counter products. Standard toxicologic management will prevent significant morbidity. No specific antidote exists.

Emergency Service, Hospital

Regulatory domains within the P0 promoter of human c-myc.

Expression of P0 RNA in some Burkitt lymphoma cell lines varies independently of levels of RNA derived from P1 and P2. These data suggest the possibility that expression of P0 RNA may be capable of independent regulation. In order to investigate this possibility we have isolated putative regulatory domains flanking P0 RNA starts within the human c-myc gene and analysed both their ability to direct expression of control reporter genes and their ability to interact with specific transcription factors. Regulatory regions necessary for expression of P0 RNA have been located within 131 bp 5' of the first major P0 RNA start. DNAase 1 footprint analysis and gel retardation assays demonstrate binding of transcription factors Sp1, NF1 and CBP to this region. NF1 binds specifically to two consensus sequences. The more distal site overlaps with the binding site for CBP, and it is likely that concomitant binding of NF1 and CBP within the distal region of the P0 promoter is not possible. Previous work from our laboratory has described a negative regulatory domain within the 5' flanking region of c-myc. The P0 promoter resides within this domain and therefore may contain a negative regulator of c-myc gene expression.

Animals

Cross-sectional internal diameters of human cervical and femoral blood vessels: relationship to subject's sex, age, body size.

Cross-sectional internal diameter measurements were made of right and left common carotid and right femoral arteries and right and left internal jugular, superficial femoral, and common femoral veins in 32 normal human subjects utilizing duplex ultrasonography. The relationships of these vessel sizes to the subject's sex, age, height, weight, and body surface area were analyzed statistically; and graphs were constructed, indicating the relationship of blood vessel diameters to the various body size parameters. Findings indicate that 1) for the femoral veins, body surface area had the best correlation with the internal diameter of the vein; 2) for the right internal jugular vein, body weight had the best correlation with the internal diameter of the vein; 3) correlation between vein diameter and body size of the subject is better for the femoral veins than for the internal jugular veins; 4) internal diameter of the femoral and internal jugular veins increases about 20% when they are distended by 15 degrees of positional inclination of the subject's body; 5) neither age nor sex of the subject influences the positional distensibility of the veins examined; 6) the cross-sectional internal diameter of the femoral and internal jugular veins, as determined by duplex ultrasonography, closely relates to the external diameter of these vessels as measured by direct in vivo application of calipers and to the maximum outside diameter of cannula the vessel will accept.

Adolescent

Temporal changes in plasma and liver lipids and in the hepatic activities of acetyl-coenzyme a carboxylase and fatty acid synthetase after oestrogen treatment of the male chicken (Gallus domesticus).

1. Male chickens (Gallus domesticus) were treated with a single intramuscular injection of oestradiol-17 beta, then changes in the liver and plasma levels of triacylglycerol, phospholipid, nonesterified fatty acids and in the hepatic activities of acetyl-CoA carboxylase and fatty acid synthetase were measured at various times after injection. 2. The results suggest that the initial phase (less than 20 hr) of oestrogen-induced hyperlipidaemia occurs in the absence of changes in the hepatic activities of the major enzymes of fatty acid biosynthesis, but a subsequent increase in these enzyme activities may contribute to the later phase (greater than 20 hr) of oestrogen-induced lipogenesis in avian liver.

Acetyl-CoA Carboxylase

Hyperammonaemic coma in ureterosigmoid urinary diversion.

We report on a patient with ureterosigmoid anastomosis, who presented with recurrent episodes of confusion, agitation and aggressive behaviour, culminating in coma. Investigations revealed profound hyperammonaemia, which responded to treatment with sodium benzoate and sodium phenylacetate. No definite cause was found for the abnormality, apart from possible urinary tract infection. The patient remains well on a protein restricted diet with mildly elevated levels of plasma ammonia.

Amino Acids

In vivo effects of corticosteroids on human allergic responses. I. Effects of systemic administrations of steroids.

In order to better understand the effects of corticosteroids in allergic disease, the relative degrees of allergen-induced cutaneous histamine release and granulocyte accumulation were evaluated in atopic volunteers following intravenous placebo or methylprednisolone administration. In nine subjects, a single intravenous dose of methylprednisolone (1 mg/kg) did not inhibit histamine release but did significantly reduce granulocyte accumulation at both allergen and buffer-challenged sites during five and one-half to six and one-half hours following steroid injection. These findings suggest that the corticosteroid-induced anti-inflammatory effects at allergic reaction sites do not include inhibition of local mediator release. Furthermore, the steroid-induced inhibition of inflammatory cell accumulation is not specific for the allergic reaction.

Administration, Oral

Lipid metabolites and nitrogen balance after abdominal surgery in man.

The relation of lipid metabolism to nitrogen balance was studied in patients having undergone abdominal surgery and was compared with control subjects who had fasted for a similar period. The patients had lower circulating concentrations of glycerol, non-esterified fatty acids and ketone bodies. There were inverse correlations between blood alanine and ketone body concentrations in both patients (r = -0.64, P less than 0.01) and controls (r = -0.58, P less than 0.01). Nitrogen excretion by patients (12.7 mmol/kg body weight/day +/- 1.4 s.e. mean) was greater than by controls (9.2 mmol kg(-1)d(-1) +/- 0.8, P less than 0.05), but a more marked difference was noted for urinary methyl histidine excretion of 5.1 +/- 0.5 mmumol kg(-1) d(-1) by patients and only 2.5 +/- 0.3 mumol kg(-1) d(-1) by controls (P less than 0.01), a disparity indicative of more active protein turnover after surgery.

Abdomen

Prevention of amino acid losses during peritoneal dialysis.

The addition of amino acid supplements to peritoneal dialysis fluid has been studied in 8 patients with compromised renal function requiring peritoneal dialysis. By the addition of 10 ml of Vamin-glucose solution to each one litre of peritoneal dialysate, amino acid losses were curtailed, no significant alterations occurred in the plasma amino acid concentrations, there were no local complications and no infections were seen. This procedure is recommended as a safe, simple way of keeping a patient in positive amino acid balance during peritoneal dialysis.

Amino Acids

Evaluation of a high nitrogen source amino acid solution ('Aminofusin' L Forte).

A new high concentration nitrogen source solution ('Aminofusin' L Forte) was evaluated in 9 patients requiring complete parenteral nutrition regimens. Excellent clinical tolerance was observed and the solution proved capable of maintaining patients in nitrogen balance. Although the non-essential part of the amino acid profile is incomplete, no significant deviations from the normal range in plasma amino acid concentrations were noted. It is concluded that the solution is a useful addition to the range of amino acid preparations available for intravenous feeding.

Adult

Ventricular tachycardia due to cardiac ischaemia: assessment by exercise electrocardiography.

Although ventricular tachycardia is a well-known complication of myocardial ischaemia and may be provoked by exercise, many patients may appreciate only the angina and be unaware of the unduly rapid heart rate that precipitates it. Exercise testing is needed to show this arrhythmia and to enable treatment to be started.Twenty-three patients were found to have chronic ischaemic heart disease complicated by ventricular tachycardia. Six patients with old myocardial infarction had ventricular tachycardia at rest which required conversion to sinus rhythm; 17 patients developed ventricular tachycardia only when they exercised. In 12 of these 17 patients coronary angiography showed disease of the anterior descending branch of the left coronary artery; other vessels were usually also affected. Although beta-adrenergic blocking drugs increased exercise tolerance, ventricular tachycardia still occurred when the heart rate on exercise reached a level similar to that before treatment. In five patients coronary artery bypass surgery was performed because of angina and exercise-induced ventricular tachycardia. Exercise tolerance was increased in all three patients who underwent exercise tests after operation, and in two of these patients, both of whom were known to have patent grafts, ventricular tachycardia was abolished.If part of the beneficial effect of coronary bypass surgery is preventing life-threatening ventricular arrhythmias it is essential to detect these, and ambulatory monitoring and stress testing have a complementary role.

Adult