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A D Wright

Publications and source records attributed to A D Wright.

At least 19 recordsLinked to original sources

Balanitoside, a furostanol glycoside, and 6-methyldiosgenin from Balanites aegyptiaca.

In addition to a known spirostanol glycoside, balanitin-3, and a new sapogenol, 6-methyldiosgenin, a new furostanol saponin, balanitoside has been isolated from the fruits (mesocarp) of Balanites aegyptiaca. The structure of the glycoside has been determined as 26-O-beta-D-glucopyranosyl-3 beta, 22,26-trihydroxy-furost-5-ene 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-(1-->4)-beta-D-glucopyranoside, on the basis of spectroscopic and chemical evidence.

Carbohydrate Sequence

Antimalarial activity of sesquiterpenes from the marine sponge Acanthella klethra.

Five sesquiterpenoids containing isonitrile or isothiocyanate groups were isolated from the sponge Acanthella klethra. Compounds 1 and 2 were identified as axisonitrile 3 and the corresponding isothiocyanate derivative, respectively. Compounds 3-5 were found to be eudesmane sesquiterpenes. None of these compounds was cytotoxic toward cultured KB-3 cells, but varying degrees of activity were observed with cultured Plasmodium falciparum. Compound 1 demonstrated greatest promise as an antimalarial agent.

Animals

Acetazolamide and high altitude diseases.

Acetazolamide is a useful prophylactic for acute mountain sickness causing marked reduction in headache, nausea, vomiting, weakness, etc. Improvements correlate with increased arterial oxygen concentrations, reduction in proteinuria and peripheral oedema and other objective measures of acute mountain sickness. Evidence that Acetazolamide is beneficial for pulmonary oedema or cerebral oedema is scanty because of the lower frequency of these severe forms of mountain sickness. Dexamethasone, used prophylactically, also reduces the symptoms of acute mountain sickness partly due to its euphoric effect. Use of Acetazolamide as a treatment for established acute mountain sickness has been investigated. Large doses of Acetazolamide increase arterial oxygen levels over a few hours and this leads to a reduction of symptoms but data is limited and faster acting carbonic anhydrides inhibitors such as Methazolamide may be preferable in an emergency situation. There is no comparison of the effectiveness of Acetazolamide with other drugs used for treating acute mountain sickness such as steroids and calcium channel blocking drugs. Also, there is no data on drug combinations which could have additive effects and thereby be more beneficial than individual drugs.

Acetazolamide

The maize auxotrophic mutant orange pericarp is defective in duplicate genes for tryptophan synthase beta.

orange pericarp (orp) is a seedling lethal mutant of maize caused by mutations in the duplicate unlinked recessive loci orp1 and orp2. Mutant seedlings accumulate two tryptophan precursors, anthranilate and indole, suggesting a block in tryptophan biosynthesis. Results from feeding studies and enzyme assays indicate that the orp mutant is defective in tryptophan synthase beta activity. Thus, orp is one of only a few amino acid auxotrophic mutants to be characterized in plants. Two genes encoding tryptophan synthase beta were isolated from maize and sequenced. Both genes encode polypeptides with high homology to tryptophan synthase beta enzymes from other organisms. The cloned genes were mapped by restriction fragment length polymorphism analysis to approximately the same chromosomal locations as the genetically mapped factors orp1 and orp2. RNA analysis indicates that both genes are expressed in all tissues examined from normal plants. Together, the biochemical, genetic, and molecular data verify the identity of orp1 and orp2 as duplicate structural genes for the beta subunit of tryptophan synthase.

Amino Acid Sequence

Growth hormone secreting pituitary carcinoma: a case report and literature review.

Only five cases of growth hormone secreting pituitary carcinoma have been documented. We present a 49-year-old West Indian male with grossly elevated plasma growth hormone (760-10,400 mU/l), and a large aggressive pituitary tumour that continued to grow despite repeated pituitary surgery, radiotherapy and medical therapy (bromocriptine and somatostatin analogue). Thirteen years after diagnosis the patient died secondary to left ventricular failure. A post-mortem revealed a large locally invasive pituitary tumour, but in addition numerous tumour seedlings within the cerebrospinal fluid space, and a solitary intraparenchymal tumour deposit within the right temporal lobe, clearly separate from the primary tumour. Pituitary carcinoma should be considered in any acromegalic with grossly elevated plasma growth hormone levels who fails to respond to conventional therapy.

Acromegaly

Beta-adrenoceptor-blocking drugs and blood sugar control in diabetes mellitus.

The effects on diabetic control of the relative cardioselective beta-blocker metoprolol and the non-selective drug propranolol were compared in 20 hypertensive diabetic patients receiving diet alone or diet and oral hypoglycaemic agents. Each drug was given for one month in a double-blind, cross-over study. Fasting, noon, and mid-afternoon blood sugar concentrations rose by 1.0-1.5 mmol/l (18-27 mg/100 ml). The rise with propranolol was not significantly greater than with metoprolol. In a few patients the rise was clinically important. The small overall change observed in diabetic control should not deter the use of beta-blockers in non-insulin-dependent diabetics, provided control is carefully monitored at the onset of treatment.

Adult

Very pure porcine insulin in clinical practice.

In a one-year follow-up study the insulin dose in diabetic patients using very pure porcine insulin was compared with that in patients using conventional preparations. The dose of insulin used to obtain diabetic control was reduced by 7% in 108 patients treated solely with very pure porcine insulin from the start of insulin treatment when compared with 108 matched patients who had received conventional insulins. In 117 patients whose treatment had been changed from conventional bovine or bovine-porcine insulin to very pure porcine insulin the dose was reduced by 9%. A further 511 patients receiving conventional insulins were examined for local cutaneous or subcutaneous abnormalities at insulin injection sites. Lipoatrophy was found in 49 of these patients (10%), but not in patients using very pure porcine insulin. The results confirm that very pure porcine insulin reduces the insulin dose needed to maintain diabetic control and may resolve or prevent local reactions such as lipoatrophy. Long-term advantages in reduced antigenicity to insulin and contaminating peptides remain to be established.

Adolescent

Birmingham Medical Research Expeditionary Society 1977 Expediton: thyroid function and acute mountain sickenss.

In a study of 17 subjects plasma-thyroxine-binding globulin and plasma thyroxine concentrations rose during a high altitude trek. An early and sustained rise in plasma reverse triiodothyronine occurred independently of changes in plasma thyroxine and was probably related to physical exertion. Similar changes in thyroid function were found in subjects most affected and least affected by acute mountain sickness.

Adult

Renal disease.

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Humans

Viral hepatitis.

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Hepatitis

Diabetes mellitus and coeliac disease: a clinical study.

Fourteen adults in whom diabetes mellitus and coeliac disease coexist, are described. In no patient was coeliac disease diagnosed (biopsy proven) before the age of 28 years. Diabetes was recognized before coeliac disease in all except one. Diabetic control was very unstable and hypoglycaemia particularly troublesome before treatment with a gluten free diet. Following gluten restriction, insulin requirement increased in six patients, and diabetic control became more stable. Diarrhoea due to coeliac disease in a patient with coexisting diabetes, may be mistakenly diagnosed as 'diabetic diarrhoea'. However, certain clinical and laboratory features should arouse suspicion that the diarrhoea is not of diabetic origin. These included a history of gastrointestinal symptoms preceding the diagnosis of diabetes, the occurrence of repeated hypoglycaemia, absence of neuropathy, anaemia, low serum folate, low serum albumin and a malabsorption pattern on small bowel radiography. A definitive diagnosis of coeliac disease can be made only jejunal biopsy. The opportunity to diagnose coeliac disease in adult diabetics will usually fall to the diabetologist and wider use of jejunal biopsy in diabetics with chronic or recurrent diarrhoea is suggested.

Adult