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Biomedical subjects

G Whiting

Publications and source records attributed to G Whiting.

15 recordsLinked to original sources
PubMed2006

Is the recommended target of 4 hours from head injury to emergency craniotomy achievable?

Guidelines recommend that head-injured patients who require life-saving decompressive surgery should undergo surgery within 4 h. To assess the compliance with this recommendation 100 consecutive head-injured patients admitted to a regional neurosurgical unit (RNU) were studied. Time points from head injury to craniotomy were documented and analysed. Twenty-four patients underwent emergency craniotomy, only one being operated on within 4 h. In this cohort of patients there was no relationship between timing of surgery and outcome. In order to investigate whether it is possible to reduce delays in transportation time, theoretical models were created to determine whether direct transfer to the RNU would be faster by land or air ambulance.

Adolescent↗
PubMed1999

Omeprazole plus antibiotics in the eradication of Helicobacter pylori infection: a meta-regression analysis of randomized, controlled trials.

This article presents a meta-regression analysis of published studies of omeprazole plus antibiotics (amoxicillin, clarithromycin, or an imidazole derivative) in the treatment of Helicobacter pylori. Eligible studies were all randomized, controlled trials published through April 1996 with 10 or more patients receiving omeprazole plus antibiotics for 5 or more days and testing for H. pylori eradication 4 weeks or more after treatment. Probability of eradication was calculated for each treatment arm, and logistic regression was performed using study characteristics as covariates. Seventy-four studies involving 117 treatment arms with 4,769 patients were identified. The eradication rate was 76% for omeprazole plus clarithromycin and 65% for omeprazole plus amoxicillin dual regimens (P <.0001). Eradication rates for triple regimens were 82%, omeprazole plus amoxicillin plus clarithromycin; 83%, omeprazole plus amoxicillin plus imidazole; and 89%, omeprazole plus clarithromycin plus imidazole. In a multiple logistic regression analysis, significant factors were antibiotic, disease, omeprazole dose, and whether treatment was followed by maintenance omeprazole. A systematic overview of the best available evidence suggests that dual therapy with omeprazole plus clarithromycin is superior to omeprazole plus amoxicillin. Triple therapy is better than dual therapy. Treatment works better on ulcers than on nonulcer dyspepsia. Higher doses of omeprazole give better results. Additional trials exploring higher omeprazole doses for varying durations as well as cost, side effects, and compliance trade-offs with efficacy are recommended.

Anti-Bacterial Agents↗
PubMed1996

Searching for signals: mortality and cardiovascular events in published randomized control trials of nifedipine in ischemic heart disease and hypertension.

UNLABELLED: META-ANALYSIS: A meta-analysis of published randomized control trials of nifedipine in hypertension and stable angina pectoris was performed. RESULTS: The results suggest a formulation-dependent increased risk of mortality and adverse cardiovascular outcomes for monotherapy use in patients with stable angina pectoris. No increased risk was seen in the hypertension studies.

Humans↗
PubMed1995

Evaluation of retinoid lactones as topical therapeutic agents in dermatology.

PURPOSE: Optimization of the therapeutic ratio of analogs of the topically active 11-cis, 13-cis-12-hydroxymethylretinoic acid, delta-lactone (1) relative to antihyperproliferation and antihyperkeratinization vs. toxicity. METHODS: Nine analogs of 1, in which variations were made in the lipophilic cyclohexenyl moiety or in the lactone ring, were evaluated for topical activity against hyperkeratinization, inhibition of TPA-induced DNA synthesis and for skin irritation. RESULTS: Although more potent lactones than the parent lactone 1 were identified, none possessed the favorable therapeutic ratio associated with 1. CONCLUSIONS: The delta-lactone 1 possesses unique molecular features responsible for its desirable therapeutic ratio as an antihyperproliferative and antihyperkeratotic agent. In view of its very low systemic retinoid toxicity and the absence of any systemic toxicity, this lactone may be a good candidate for use in the topical treatment of acne.

Administration, Topical↗
PubMed1995

Retinoic acid receptor gamma mediates topical retinoid efficacy and irritation in animal models.

Among retinoic acid receptors (RARs) alpha, beta, and gamma, the messenger RNA level of RAR-gamma is the most readily detectable by Northern blotting in human and mouse skin. This observation suggests that RAR-gamma may play a critical role in the modulation of the therapeutic benefits and side effects of retinoids in skin. To test this hypothesis, 11 RAR-gamma selective retinoids were synthesized based on three related structures. Each compound was found to prefer RAR-gamma when assessed by retinoid-induced transcriptional activity (RAR-gamma > RAR-beta > RAR-alpha). The apparent Kd for binding to recombinant receptor protein was found to follow a similar trend. To correlate this receptor selectivity with in vivo activity, the compounds were tested topically in the Rhino mouse utriculi reduction and rabbit irritation models, two assays widely used to screen retinoids for efficacy and side effects, respectively. The results indicated that for these compounds, both efficacy in the utriculi reduction assay and irritation potential in rabbits correlated positively with the RAR-gamma transactivation activity, with r2 of 0.9 and 0.8, respectively. These data suggest that RAR-gamma is an important regulator of retinoic acid efficacy in skin and further, that the irritation associated with the use of retinoids is most likely a receptor-mediated process.

Animals↗
PubMed1995

In-vivo activity of retinoid esters in skin is related to in-vitro hydrolysis rate.

BMS-181163 (4-acetamidophenyl retinoate, previously reported as BMY-30123), the acetamidophenyl ester of all-trans-retinoic acid (tRA), is topically active in various retinoid-sensitive animal models, but was recently shown to be ineffective for the treatment of acne in patients. To determine whether BMS-181163 functions as a prodrug of tRA in mice but not in man, the relative rates of ester hydrolysis in mouse and human skin homogenates were determined. In-vitro hydrolysis assays showed that BMS-181163 was substantially hydrolysed in mouse skin homogenates and minimally in human skin preparations. In addition, a series of phenyl esters of tRA and several known active synthetic retinoids (Ch-80: (E)-4-[3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1 - propenyl] benzoic acid; CD-271: 6-[3-(1-adamantyl)-4-methyoxyphenyl]-2-naphthoic acid; and TTNPB: (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1- propenyl] benzoic acid) was prepared and hydrolysis rates and in-vivo (rhino mouse utriculi reduction) activities were compared. The hydrolysis rates of the six test retinoid phenyl esters, ranging from 0.06 to 2.0 h-1 were found to correlate with the in-vivo activity. Those esters (BMS-181163 and acetamidophenyl esters of Ch-80 and TTNPB) with a higher hydrolysis rate exhibited in-vivo activity only slightly lower than their parent free acid retinoids. In contrast, the three phenyl esters with a hydrolysis rate less than 0.3 h-1 were inactive in-vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adapalene↗
PubMed1995

Role of retinoic acid receptor gamma in the Rhino mouse and rabbit irritation models of retinoid activity.

The three retinoic acid receptors (RAR alpha, RAR beta and RAR gamma) are known to modulate the transcription of target genes through interaction of the individual receptors with their naturally occurring ligand, retinoic acid (RA). Since RA has multiple effects in vivo, considerable effort has recently been devoted to finding selective compounds to elucidate the functions of individual receptors and to relate these functions to specific in vivo effects. The racemic synthetic retinoid 6-[(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl)hydroxy-methyl]-2- naphthalene carboxylic acid has recently been identified as an RAR gamma-selective agonist. A synthetic method involving lipase-mediated transformation has been developed to prepare the individual enantiomers. Discrimination between the two enantiomers is seen in both transcriptional activity and binding to recombinant receptors with the (S)-enantiomer being the more active. Differences between the two compounds are also seen in the Rhino mouse utriculi reduction assay and the rabbit irritation model. In both animal models, the (S)-enantiomer consistently gave a greater response. Taken together, these results suggest that the activity and irritation seen with RA and related compounds is receptor mediated. Further, the strong selectivity of the compounds reported here for RAR gamma suggests that this receptor plays an important role in these in vivo biological activities. The discrimination between these enantiomers may be useful in the design of novel retinoids with uniquely defined biological properties.

Animals↗
PubMed1994

Evaluation of retinoids as therapeutic agents in dermatology.

Evaluation of 13-cis-12-substituted analogues of retinoic acid in a series of dermatologic screens has revealed that structural modifications can lead to selectivity and specificity. An analogue, 11-cis,13-cis-12-hydroxymethylretinoic acid, delta-lactone, has been found to have good activity and to be devoid of topical and systemic toxicity.

Administration, Topical↗
PubMed1992

The pharmacology of a novel topical retinoid, BMY 30123: comparison with tretinoin.

Preclinical studies pertaining to the pharmacology and toxicology of BMY 30123 (4-acetamidophenyl retinoate) are reported. BMY 30123 is a novel compound which has topical retinoid activity. This compound exhibits lower toxicity, both local and systemic, than other clinically used topical retinoids such as tretinoin (all-trans retinoic acid) in animal models. BMY 30123 is effective in a number of retinoid sensitive skin models including the rhino mouse utriculi reduction assay, the mouse epidermal hyperplasia model and in the suppression of DNA synthesis in mouse skin stimulated with phorbol ester. BMY 30123 was equipotent with tretinoin in these topical models. In the rhino mouse model the ED30 values for BMY 30123 and tretinoin were 0.037 and 0.015 mM, respectively. In addition, BMY 30123 was active in the UVB-induced photodamaged mouse model, another retinoid sensitive model. One of the problems associated with topically applied tretinoin is local irritation. Therefore, for topical therapy to be optimal, it is important to reduce or minimize local irritation. Repeated applications of BMY 30123 to rabbit skin resulted in low skin irritation. The first perceptible signs of skin irritation produced by BMY 30123 occurred at a dose 10 times higher than that observed for tretinoin. BMY 30123 also exhibits low retinoid activity after oral or i.p. administration in mice and produced no signs of hypervitaminosis A-related toxicity at twenty times the no effect dose of tretinoin. Because retinoids are effective modulators of epidermal growth and differentiation, this compound should be useful for the treatment of cutaneous disorders that exhibit altered epidermal differentiation such as acne, psoriasis, ichthyosis and epithelial tumours.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗
PubMed1989

Spontaneous rupture of the liver associated with amyloidosis.

Fatal spontaneous rupture of the liver is described in a 46-year-old women with hepatic amyloidosis diagnosed premortem by liver biopsy. An autopsy revealed systemic amyloidosis, with no evidence of an underlying chronic inflammatory condition, infection, or immunocyte dyscrasia. By computerized search, this is only the third reported case of spontaneous rupture of the liver complicating amyloidosis.

Amyloidosis↗
PubMed1980

Minoxidil and labetalol: very effective antihypertensive combination.

Minoxidil is an extremely potent hypotensive drug. Good control of refractory hypertension can be achieved without major side effects by using small to moderate doses in combination with other drugs. In particular, minoxidil and labetalol are effective when they are used with frusemide.

Adult↗
PubMed1980

Bilateral endogenous Escherichia coli endophthalmitis.

Escherichia coli endophthalmitis developed in a 62-year-old man following an inadequately treated lower urinary tract infection. Treatment with intravenous and local antibiotics and steroids was successful in eradicating the infection, but blindness was not reversed. The pathogenesis and management of secondary bacterial endophthalmitis are reviewed.

Escherichia coli Infections↗
PubMed1975

Mouth lesions in iron-deficient anemia: relationship to Candida albicans in saliva and to impairment of lymphocyte transformation.

The atrophic glossitis and angular chilosis in patients with iron-deficient anemia are associated with infection of the mouth by Candida albicans. Saliva from these patients contained more Candida and supported the growth of Candida better than did saliva from a control group. The possibility that growth of Candida may be due to impaired lymphocyte function was investigated by measuring transformation of lymphocytes stimulated with phytohemagglutinin. Transformation was depressed in iron-deficient subjects and returned to normal after correction of their iron status. The lymphocyte count in the peripheral blood was also depressed and corrected by additional iron. Impaired lymphocyte function did not explain the mouth lesions and growth of Candida in saliva since lymphocyte transformation was equally depressed in patients with and without mouth lesions. A local factor, such as an effect of lack of iron on the resident vacterial flora of the mouth, may be important.

Adolescent↗