PubMed Health⌕ Search

Biomedical subjects

W J Watkins

Publications and source records attributed to W J Watkins.

17 recordsLinked to original sources
PubMed2005

Blepharophimosis and bilateral Duane syndrome associated with a FOXL2 mutation.

This case describes the novel coexistence of sporadic blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) and bilateral type I Duane syndrome in a female infant, with a FOXL2 mutation. Mutational analysis of FOXL2 demonstrated a 30-nucleotide duplication (c.672(-)701dup30) within the polyalanine tract of FOXL2. The association of BPES and Duane syndrome represents a novel phenotype which may suggest a greater pleiotropic effect of FOXL2 in development. During the period of the 4-8th week of embryonic development, the cranial nerves, their nuclei and the corresponding innervation to the extraocular muscles develop, the extraocular muscles undergo development and differentiation. This coincides with the period of time that FOXL2 is expressed strongly in the developing eyelids and the surrounding tissues. Forkhead genes are transcription factors and likely to be involved in signal transduction pathways. This case expands the spectrum of FOXL2 mutations associated with BPES.

Base Sequence↗
PubMed2001

Efflux pumps: their role in antibacterial drug discovery.

The emergence of active efflux as a major causative factor in antibiotic resistance has been one of the most significant trends in antiinfective chemotherapy over the last decade. The phenomenon affects virtually all classes of antibiotics and frequently results in multi-drug resistant phenotypes. This review analyzes efflux pumps of clinical significance and examines their impact on different antibiotic classes relative to other mechanisms of resistance. Progress in strategies to combat efflux-mediated resistance by modification of existing antibiotics or identification of efflux pump inhibitors is also reviewed.

Anti-Bacterial Agents↗
PubMed1994

Comparison of 16-androstene steroid concentrations in sterile apocrine sweat and axillary secretions: interconversions of 16-androstenes by the axillary microflora--a mechanism for axillary odour production in man?

The concentrations of five 16-androstene steroids were determined, by a GC-MS method, in freshly-produced apocrine sweat (adrenaline-induced), in 8 men and 2 women. The ranges of concentrations (nmol/microliter) in apocrine sweat were: 5 alpha-androst-16-en-3-one (5 alpha-A), 0.1-2.0 and 4,16-androstadien-3-one (androstadienone), 0-1.9, 5,16-Androstadien-3 beta-ol (androstadienol) was also found in 5 of the subjects (range 0.05-1.05). 5 alpha-Androst-16-en-3 alpha- or 3 beta-ols [3 alpha (beta)-androstenols] were only found in small amounts (< 0.1 nmol/microliters) in a few subjects. In the second study, prior to apocrine sweat collection (adrenaline injection), the axillary skin of 6 of the male subjects was washed with diethyl ether on an adjacent site of the axillary vault. The concentrations of 16-androstenes were compared in the ethereal extracts and apocrine sweat. The former contained detectable levels (pmol/cm2) of androstadienone (17.9 +/- 2.4), 3 alpha-androstenol (6.9 +/- 3.7), 3 beta-androstenol (1.8 +/- 1.0) and androstadienol (1.9 +/- 0.5) (means +/- SEM) in all 6 subjects. All but 1 subject also had 5 alpha-androstenone, the mean value for the others being 2.5 +/- 0.6. The axillary skin levels of 3 alpha- and 3 beta-androstenols, androstadienol and, in 3 subjects, androstadienone exceeded those in the apocrine sweat obtained from the same subjects, whereas levels of 5 alpha-androstenone in the skin extracts were all lower than in apocrine sweat samples, when related to the corresponding areas of skin sampled. The metabolism of 16-androstenes was studied in vitro in the presence of two aerobic coryneform bacteria, previously shown to metabolize testosterone as well as being capable of producing odour from extracts of axillary sweat in an odour-generation test. Although both coryneforms caused complex metabolic reactions and were capable of oxidation or reduction at C-3 and C-4, the overall direction favoured reduction. For example, large quantities of the more odorous 5 alpha-androstenone and 3 alpha-androstenol were formed from androstadienol and androstadienone. In contrast, strains of corynebacteria, unable to produce odour and incapable of metabolizing testosterone, were also unable to metabolize 16-androstenes.(ABSTRACT TRUNCATED AT 400 WORDS)

Actinomycetales↗
PubMed1991

Applications of gas chromatography-mass spectrometry in the study of androgen and odorous 16-androstene metabolism by human axillary bacteria.

The known involvement of axillary microflora with under-arm odour (UAO) production led us to determine whether the odorous 16-androstene steroids are formed in the axilla by bacterial metabolism of an odourless precursor such as testosterone. Axillary bacteria from 34 men were selectively cultured for aerobic coryneform bacteria (ACB), Micrococcaceae and propionibacteria. Overnight suspensions of bacteria were incubated separately at 37 degrees C for two weeks with radiolabelled testosterone plus unlabelled testosterone (0.5 mg) and 0.5-mg quantities of 4,16-androstadien-3-one (androstadienone) and 5,16-androstadien-3 beta-ol (androstadienol). After extraction and purification by Sep-Pak cartridges and thin-layer chromatography, the eluted steroids were derivatised as the pentafluorobenzyl oximes (PFBO) and tert.-butyl dimethylsilyl (TBDMS) ethers. Saturated analogues were used as internal standards. Selected-ion monitoring electron-impact mass spectrometry was performed at the m/z corresponding to the M+.ion for the PFBO derivatives and the [M - 57]+ ion for the TBDMS ethers. Only ACB produced classical musk-like UAO (UAO + ve) in an in vitro odour-producing system with 29% being UAO -ve. ACB (UAO +ve) metabolised far more (p = 0.001) testosterone than ACB (UAO -ve), the principal metabolites being 5 alpha(beta)-dihydrotestosterone, 5 alpha(beta)-androstane-3,17-dione and 4-androstene-3,17-dione (4-androstenedione). No non-polar 16-androstenes were formed. Micrococcus luteus (ten strains) metabolised testosterone to 4-androstenedione only; propionibacterium spp. did not metabolise testosterone at all. However, incubation of 16-androstenes with ACB gave evidence for 4-ene-5 alpha(beta)-reduction, 3 alpha(beta)-oxido-reduction and epimerisation. In general the direction of transformations favoured formation of the more odorous 5 alpha-androst-16-en-3-one (5 alpha-androstenone) and 5 alpha-androst-16-en-3 alpha-ol (3 alpha-androstenol) from less odorous steroids. Such transformations, in vivo, would not require de novo synthesis of 5 alpha-androstenone or 3 alpha-androstenol and would be consistent with utilisation by ACB of 16-androstenes already present in small quantities in fresh apocrine secretions, which are odourless, to produce a more powerfully smelling mixture on the axillary skin surface.

Androgens↗
PubMed1988

Properties of 4-ene-5 alpha-reductase and studies on its solubilization from porcine testicular microsomes.

The activity of 4-ene-5 alpha-reductase was assayed in porcine testis homogenates and subcellular fractions, using testosterone as substrate. 'Marker' enzyme activities were utilized to indicate the purity of the subcellular fractions. 4-Ene-5 alpha-reductase activity was associated with the microsomal fraction; there was no activity in the purified nuclear fraction. Enzyme activity was higher in the testes of 6 week old pigs than those of 3 and 17 week old animals, and a range of activity was found. The enzyme was unstable when stored at -20 degrees C but the addition of albumin (0.1%, w/v) or glycerol (20%, v/v) to the buffer and storage at -70 degrees C or in liquid nitrogen ensured that maximal activity was retained for at least 35 days. In addition to 5 alpha-DHT, other 5 alpha-reduced metabolites and 4-androstenedione were formed in this reaction; NADPH was the preferred cofactor, but 40% of the 4-ene-5 alpha-reductase activity was retained when NADH was used. Solubilization of the microsomal enzyme was achieved using sodium citrate (0.1 M); 4-ene-5 alpha-reductase activity was enhanced to greater than 120% and 60% of this activity was in the soluble fraction. The optimum pH and temperature for both soluble and membrane-bound 4-ene-5 alpha-reductase were 6.9 and 32 degrees C, respectively. The mean apparent Km and Vmax were 0.6 mumol/l and 158 pmol/min/mg microsomal protein for the microsomal enzyme and 1.42 mumol/l and 212.0 pmol/min/mg soluble protein for the solubilized 4-ene-5 alpha-reductase. The estimated sedimentation coefficient was 11.6.

Animals↗
PubMed1984

Developmental changes in lactate dehydrogenase and aldolase activity of the A2G-adr mouse with abnormal muscle function: further comparison with the 129Re-dy mutant.

Lactate dehydrogenase and aldolase activity were reduced in lateral gastrocnemius muscle from two mouse mutants, A2G-adr and 129Re-dy, with abnormal muscle function. The activities of both of these enzymes were significantly reduced in the lateral gastrocnemius muscle from the A2G-adr mice at ages varying from 2 weeks to 32 weeks, whereas the activities in the soleus, heart, liver, and brain were the same as in the control animals. The lactate dehydrogenase isoenzymes in the lateral gastrocnemius and soleus muscles from the A2G mice were quantified, and although those of the soleus were comparable in mutant and control muscle, the lateral gastrocnemius from the adr mutant had reduced activity of LDH 5 and increased activities of the other four isoenzymes. The findings suggest that the adr mutation is expressed in the white (Type II) muscle fibres and not in the red (Type I) fibres or in any of the organs studied. It is suggested that the initiation of differentiation into Type II fibres from the embryonic form is absent or delayed in the A2G mutant. The reduced activities of lactate dehydrogenase and aldolase in 129Re-dy muscle confirm the findings of other workers.

Aging↗
PubMed1984

Biological features of the new A2G--adr mouse mutant with abnormal muscle function.

A new mouse mutant (A2G-adr) with abnormal muscle function is described and has been compared with the 129 Re dystrophic mouse. The mutation, which is due to an autosomal gene defect, results in myotonic-like spasms, progressive muscle weakness and a reduced lifespan. Affected animals were consistently lighter than normal littermates; comparison of organ weights and organ-to-bodyweight ratios indicated a slower growth rate in the mutants.

Animals↗
PubMed1980

Crohn's disease of the epiglottis, aryepiglottic folds, anus, and rectum.

A 23-year-old white women complained of sore throat and difficulty in breathing. Examination of her larynx revealed chronic inflammatory changes of the epiglottis and aryepiglottic folds, and a biopsy demonstrated chronic granulomatous reaction. Six months later she developed chronic diarrhea, rectal pain, and typical anorectal findings of Crohn's disease. Biopsy of the anus revealed the same microscopic features as in the laryngeal structures. Treatment in keeping with the acceptable but limited measures for Crohn's disease brought improvement in both areas of inflammation. We feel this patient has Crohn's disease in the larynx, involvement which preceded that of the gastrointestinal tract.

Adult↗
PubMedDate not supplied

Capillary gas chromatography with chemical ionization negative ion mass spectrometry in the identification of odorous steroids formed in metabolic studies of the sulphates of androsterone, DHA and 5alpha-androst-16-en-3beta-ol with human axillary bacterial isolates.

The products of metabolism of the sulphates (0.5 micromol/l) of androsterone, dehydroepiandrosterone (DHA) and 5alpha-androst-16-en-3beta-ol have been investigated after incubation with 72 h cultures of human axillary bacterial isolates for 3 days at 37 degrees C. The medium used, tryptone soya broth (TSB), contained yeast extract and Tween 80. The isolates used were Coryneform F1 (known previously to metabolize testosterone and to be involved in under-arm odour (UAO) production, i.e. UAO +ve), Coryneform F46 (inactive in both the testosterone metabolism and UAO tests, i.e. UAO -ve) and Staphylococcus hominis/epidermidis (IIR3). Control incubations of TSB alone, TSB plus each of the steroid sulphates and TSB plus each of the bacterial isolates were also set up. After termination of reactions and addition of internal standards, 5alpha-androstan-3beta-ol and 5alpha-androstan-3-one (50 ng each), extracted and purified metabolites were subjected to combined gas chromatography-mass spectrometry with specific ion monitoring. Steroidal ketones were derivatized as their O-pentafluorobenzyl oximes; steroidal alcohols (only androst-16-enols in this study) were derivatized as their tert-butyldimethylsilyl ethers. Analysis was achieved by negative ion chemical ionization mass spectrometry for the pentafluorobenzyl oximes at [M-20]- and electron impact positive ion mass spectrometry for the tert-butyldimethylsilyl ethers at [M-57]+. The incubation broth contained two compounds which had gas chromatographic and mass spectrometric properties identical to those of DHA and 4-androstenedione. It was not possible, therefore, to show unequivocally that DHA sulphate (DHAS) was converted microbially into DHA, although this is implied by the finding of small quantities of testosterone and 5alpha-dihydrotestosterone in incubations with F1. With androsterone S, no free androsterone was recorded and only very small (5 pg or less) amounts of testosterone. Two odorous steroids, androsta-4,16-dien-3-one and 5alpha-androst-2-en-17-one (Steroid I) were formed (mean quantities 40 and 45 pg, respectively). The sulphate of 5alpha-androst-16-en-3beta-ol was metabolized with F1 into large quantities of the odorous steroids, 5alpha-androst-16-en-3-one and Steroid I. In addition, much smaller quantities of androsta-4,16-dien-3-one were formed. In contrast, incubations of DHAS with F46 resulted in no metabolites except, possibly, DHA, but the sulphate moiety of androsterone S was also cleaved to yield the free steroid together with large amounts of Steroid I. In incubations of DHAS and androsterone S with F1, no 16-unsaturated steroids were formed, although 5alpha-androst-16-en-3beta-yl S was de-sulphated and the free steroid further metabolized. No evidence was obtained for androst-16-ene metabolism in incubations with F46. In incubations with S. hominis/epidermidis (IIR3), androsterone S was converted into androsterone and, in high yield, to Steroid I plus some 5alpha-androst-16-en-3-one. Both DHAS and androsterone S were converted into androst-16-enols. Sulphatase activity was also manifested when 5alpha-androst-16-en-3beta-yl S was utilized as substrate with IIR3, large quantities of Steroid I and 5alpha-androst-16-en-3-one being formed, together with further metabolism of androst-16-enes. In view of the fact that both DHAS and androsterone S occur in apocrine sweat, the metabolism of these endogenous substrates by human axillary bacteria to several odorous steroids may have important implications in the context of human odour formation.

Actinomycetales↗