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Biomedical subjects

J A Vale

Publications and source records attributed to J A Vale.

At least 37 records · Page 2Linked to original sources
PubMed1999

Therapeutic review: do diethyldithiocarbamate and disulfiram have a role in acute nickel carbonyl poisoning?

INTRODUCTION: Sodium diethyldithiocarbamate and disulfiram have been proposed as effective nickel chelators. This paper examines the value of these compounds in the treatment of acute nickel carbonyl poisoning by reviewing published experimental and clinical data. REVIEW: In 2 studies, parenteral administration of diethyldithiocarbamate 50-100 mg/kg to rats immediately following nickel carbonyl exposure ensured the survival of all animals: Mortality fell from 73% to 8% when diethyldithiocarbamate was administered at 10 minutes in a third study. In the same study, there was no protection when diethyldithiocarbamate was administered at 6 hours, and the mortality was greater, though not significantly different, when diethyldithiocarbamate was administered at 24 hours. In another study in mice, total protection was afforded by diethyldithiocarbamate given at 8 hours but this protection was limited when diethyldithiocarbamate was administered at 24 hours, with diethyldithiocarbamate 100 mg/kg apparently being less protective than diethyldithiocarbamate 50 mg/kg. In 3 studies, oral diethyldithiocarbamate administration was less effective than parenteral administration. There are no adequately controlled clinical studies of the use of diethyldithiocarbamate in acute nickel carbonyl poisoning despite claims that this therapy has been effective in the treatment of several hundred such patients. Disulfiram, a metabolite of diethyldithiocarbamate, offered complete protection against nickel carbonyl-induced toxicity when administered in a dose of 1000 mg/kg to rats immediately following nickel carbonyl exposure. In contrast, disulfiram 500 mg/kg offered no protection and disulfiram 1500 mg/kg appeared to enhance mortality, possibly by increasing brain nickel accumulation. CONCLUSION: Animal studies demonstrate that diethyldithiocarbamate is an effective antidote in acute nickel carbonyl poisoning when it is administered parenterally soon after exposure. However, as no adequately controlled clinical studies have been performed, further clinical data are required before diethyldithiocarbamate can be recommended routinely in acute nickel carbonyl poisoning. If diethyldithiocarbamate is to be employed, it should be administered parenterally soon after exposure as delay in administration may increase nickel carbonyl toxicity. There are currently insufficient data to recommend disulfiram as an alternative to diethyldithiocarbamate even when diethyldithiocarbamate is not available.

Animals↗
PubMed1998

Toxicokinetic and toxicodynamic aspects of organophosphorus (OP) insecticide poisoning.

As the majority of OP insecticides are lipophilic and not ionised they are absorbed rapidly following inhalation or ingestion; dermal absorption is slower but severe poisoning may still ensue if exposure is prolonged. Following absorption, OP compounds accumulate in fat, liver, kidneys and salivary glands. Phosphates (P=O) are biologically active as AChE inhibitors, whereas phosphorothioates (P=S) need bioactivation to their phosphate anologues (oxons) to become biologically active. Oxons inhibit AChE by phosphorylation of the serine hydroxyl group in the substrate-binding domain of the enzyme. The rate of spontaneous reactivation of alkyl phosphorylated AChE depends on the chemical structure of the OP compound. Spontaneous reactivation of dimethyl phosphorylated AChE proceeds quite rapidly. However, unless oximes are employed, there is no such expectation of rapid recovery for patients intoxicated with diethyl phosphoryl insecticides.

Absorption↗
PubMed1998

The prospective value of the IPCS/EC/EAPCCT poisoning severity score in cases of poisoning.

INTRODUCTION: The poisoning severity score is a four-point severity-classification scale, developed by the International Programme on Chemical Safety, the Commission of the European Union, and the European Association of Poison Centres and Clinical Toxicologists (IPCS/EC/EAPCCT), for the retrospective assessment of cases of poisoning reported to poisons information centers. OBJECTIVES: The aims of this study were to test the validity of using the poisoning severity score obtained at initial referral to assess clinical severity and the likelihood of subsequent deterioration, to select cases for follow-up, and also to determine the need for referral to a clinical toxicologist. METHODS: The poisoning severity score was determined at the time of initial inquiry. Follow-up was then undertaken until either the patient was discharged from medical attention or died. A second poisoning severity score was then calculated taking note of the most severe features present after the initial inquiry. RESULTS: Of 718 consecutive telephone inquiries, 397 were given an initial poisoning severity score of 0 (no signs and symptoms), 225 a score of 1 (mild symptoms), 71 a score of 2 (moderate symptoms), and 25 a score of 3 (severe symptoms). Follow-up data are available only in 638 cases because the patient or referring doctor could not be traced in 80 instances. Of the 638 cases, 41 deteriorated; 31 of these were graded initially as poisoning severity score 0, four as 1, and six as 2. Five patients died (two with an initial score of 2 and three with an initial score of 3). CONCLUSIONS: This study demonstrates that it is useful to score telephone inquiries to a poisons information service at initial referral with the poisoning severity score. First, the poisoning severity score is helpful in assessing accurately the clinical severity and the likelihood of further deterioration. Second, the poisoning severity score is useful in determining the need for referral of the inquiry to a clinical toxicologist, thus ensuring that more serious and complicated cases of poisoning receive expert medical advice on management. Third, the poisoning severity score is helpful in selecting those cases which warrant follow-up for medical and epidemiological reasons.

Developing Countries↗
PubMed1997

A clinicopathological approach to cystitis--recommendations for simplified pathology reporting.

OBJECTIVE: To assess the accuracy of histopathology reports of bladder biopsy specimens showing chronic cystitis and to develop a standard method of reporting in the form of a template which will aid both clinician and patient in the management of this condition. MATERIALS AND METHODS: Over a 4-year period, the reports of 134 bladder biopsy specimens diagnosed as chronic inflammation of the bladder were examined for clinical details, cystoscopy findings, pathology details and conclusions. Within each of these groups, the common terms were assessed for their relevance to the final outcome. RESULTS: The analysis of each part of these reports revealed no clinical details in 33%, no cystoscopy details in 26% and no histopathology conclusion in 20%. The commonest terms used were: macroscopic haematuria (25%) for clinical details; red patch/ inflamed (40%) for cystoscopic details, morphological site involved (65%) for pathology details; and mild chronic cystitis (37%) for the conclusions. Standardized criteria were devised and after reassessing the reports, 75% were considered to be accurate and complete. CONCLUSIONS: Overall, the histopathology reports examined were more than adequate for the clinicians' use but the spectrum of details provided did not add to the usefulness of the final report. By limiting the terms available, a more standardized report can be produced, benefiting both clinician and patient.

Adult↗
PubMed1997

Haematuria.

Many serious and potentially treatable diseases of the urinary tract may have haematuria as their only manifestation. However, asymptomatic microscopic haematuria detected by dipstick testing may be seen in up to 16% of screening populations. The great majority of such cases will have no sinister underlying cause, particularly in those under 40 years of age, and so the schedule of further investigations, some of which may be invasive, time-consuming and expensive, needs to be rationalised. In addition, the increasing popularity of 'fast track' clinics for the investigation of haematuria enhances the need for a clear strategy of investigation. Analysis of the epidemiology of asymptomatic haematuria and its causes combined with a consideration of the risk-benefit profile of the available investigations, makes it possible to set out an algorithm for the initial management of this common finding. Careful clinical assessment and basic laboratory tests for renal function, analysis of the urinary sediment and cytological examination of the urine are followed by ultrasound and plain radiography of the urinary tract. Flexible cystoscopy under local anaesthetic is central to the algorithm in patients of all ages. The importance of a nephrological opinion and consideration of renal biopsy, especially in younger patients with other evidence of glomerular disease, is stressed. The role of intravenous urography in excluding pathology of the upper urinary tract, especially in patients over the age of 40, is also considered.

Adult↗
PubMed1997

Position statement: gastric lavage. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists.

In preparing this Position Statement, all relevant scientific literature was identified and reviewed critically by acknowledged experts using agreed criteria. Well-conducted clinical and experimental studies were given precedence over anecdotal case reports and abstracts were not usually considered. A draft Position Statement was then produced and subjected to detailed peer review by an international group of clinical toxicologists chosen by the American Academy of Clinical Toxicology and the European Association of Poisons Centres and Clinical Toxicologists. The Position Statement went through multiple drafts before being approved by the boards of the two societies and being endorsed by other societies. The Position Statement includes a summary statement for ease of use and is supported by detailed documentation which describes the scientific evidence on which the Statement is based. Gastric lavage should not be employed routinely in the management of poisoned patients. In experimental studies, the amount of marker removed by gastric lavage was highly variable and diminished with time. There is no certain evidence that its use improves clinical outcome and it may cause significant morbidity. Gastric lavage should not be considered unless a patient has ingested a potentially life-threatening amount of a poison and the procedure can be undertaken within 60 minutes of ingestion. Even then, clinical benefit has not been confirmed in controlled studies. Unless a patient is intubated, gastric lavage is contraindicated if airway protective reflexes are lost. It is also contraindicated if a hydrocarbon with high aspiration potential or corrosive substance has been ingested.

Acetaminophen↗
PubMed1996

A comparison of isotope penile blood flow and colour Doppler ultrasonography in the assessment of erectile dysfunction.

OBJECTIVES: To determine whether the measurement of penile blood flow by colour Doppler imaging (CDI) and the subjective impressions generated from CDI correlate with the results of measuring isotope penile blood flow (IPBF), and thus determine if CDI is a useful screening investigation for vasculogenic impotence. PATIENTS AND METHODS: The study comprised 37 men with impotence of > 6 months duration. All patients underwent CDI of the penis; the maximum systolic (vmax) and minimum diastolic velocity (vmin) were recorded. Video recordings of the CDI were reviewed subsequently with no knowledge of the erectile response. Twenty-seven patients then underwent measurement of IPBF. RESULTS: There was no relationship between the results obtained from IPBF and those from CDI, nor was there a significant difference between the vmax of patients identified as having arteriogenic impotence on IPBF and that of normal men or those with venous leakage on IPBF. There was no relationship between the subjective impressions from CDI and the results from IPBF, or with erectile response. CONCLUSIONS: There was no correlation between the results obtained on IPBF and those obtained from CDI; the latter is not useful in differentiating between venogenic and arteriogenic impotence in men who have failed to have a full response to papaverine.

Adult↗
PubMed1996

Elemental mercury-induced skin granuloma: a case report and review of the literature.

BACKGROUND: Injection of elemental mercury is rare and only some 72 cases have been reported in the literature over the period 1923-1995. Direct subcutaneous injection or extravasation of mercury injected into blood vessels can produce local granulomata and abscesses. Unless intravascular mercury injection has occurred, clinical signs of mercury toxicity are usually absent though four cases of systemic toxicity have been reported following isolated subcutaneous injection without evidence of elemental mercury dissemination. CASE REPORT: We report a further case of subcutaneous injection by gunshot of elemental mercury, with subsequent granuloma formation, in a 19-year old man who was admitted with an eight month history of a tender enlarging mass in his left antecubital fossa, while on active military service. Surgical removal of mercury from a presumed mercury-tipped bullet was undertaken but was incomplete and the patient declined further operative intervention as he remained asymptomatic. Chelation therapy was not instituted. Serum and urine mercury concentrations were measured for six years after presentation. CONCLUSIONS: We recommend that cases of subcutaneous metallic mercury injection should be managed by complete surgical excision of the granuloma under X ray control and serial monitoring of blood and urine mercury concentrations.

Adult↗
PubMed1995

Venous leak surgery: long-term follow-up of patients undergoing excision and ligation of the deep dorsal vein of the penis.

OBJECTIVE: To review the long-term results and satisfaction of patients after venous leak surgery for the management of impotence caused by a failure of passive venous occlusion. PATIENTS AND METHODS: Twenty-seven patients (mean age 56 years, range 26-63) with erectile failure due to venous leakage, diagnosed on colour Doppler imaging (CDI) and pharmacocavernosometry and cavernosography, underwent venous leak surgery. In all cases the deep dorsal vein of the penis was excised and ligated along with any other large accessory veins. Patients were reviewed in out-patients at 3 months and asked to complete a questionnaire 1 year after surgery. RESULTS: Three months after surgery, 19 of 27 patients (70%) had been able to resume sexual intercourse, 17 (63%) had spontaneous erections and two (7%) required papaverine/prostaglandin E1. One year after surgery, 14 of 22 patients were able to achieve erections sufficient for sexual intercourse, although four of these required self-injection with papaverine. There were no serious complications, and when asked whether or not they would undergo the operation again, 13 of 20 said they would. CONCLUSIONS: We conclude that venous leak surgery is a useful treatment modality in patients with pure venous leakage proven by pharmacocavernosometry and/or cavernosography, and in whom arteriogenic impotence has been excluded using CDI. These are often desperate patients who would rather accept the risk that this relatively minor procedure may fail in preference to undergoing implant surgery in the first instance or use a vacuum device. However, well-informed consent is essential.

Adult↗
PubMed1995

Deaths from pesticide poisoning in England and Wales 1990-1991.

1. Data on deaths from pesticide poisoning occurring in England and Wales in 1990 and 1991 have been collated. Pesticides were responsible for 44 of 3978 deaths from poisoning (excluding carbon monoxide and other gases) over this period. 2. At least 66% of all pesticide fatalities were due to suicide and overall there was a predominance of males (male:female ratio 2.4:1). Eighty per cent of deaths occurred in those more than 44 years old and no child under 10 years old died, although almost 50% of suspected pesticide poisoning incidents involve this age group. 3. Herbicides were responsible for 35 of the 44 deaths; seven were caused by insecticides, one by a molluscicide and one by an unspecified agent. The herbicide, paraquat, was responsible for 33 of 44 deaths (75%) and, although fewer fatalities have occurred from this cause in recent years, paraquat remains the most common cause of fatal pesticide poisoning in England and Wales.

Adolescent↗
PubMed1995

Pesticide incidents reported to the Health and Safety Executive 1989/90- 1991/92.

1. Data concerning pesticide incidents investigated by the Field Operations Division (FOD) of the Health and Safety Executive (HSE) in Great Britain have been collated for the three year period April 1989 to March 1992. Over this period the HSE investigated 613 incidents concerning pesticides: 338 related to general or environmental complaints not involving human poisoning and 275 were suspected poisoning incidents. 2. The two hundred and seventy-five suspected poisoning incidents were assessed by the Pesticide Incidents Appraisal Panel (PIAP) as 'confirmed', 'likely', 'unlikely', 'not confirmed', or that there were 'insufficient data' to make an assessment. Assessed data are unavailable for eight incidents reported in 1989. 3. Four hundred and eighteen members of the public were involved in 202 assessed incidents and 79 workers were exposed in 65 assessed incidents. Overall, 129 (48%) incidents were assessed as 'confirmed' or 'likely', 121 (45%) as 'unlikely' or 'not confirmed' and in 17 (6%) there were 'insufficient data' to form a judgement. Incidents occurring in an occupational setting were assessed as 'confirmed' or 'likely' more frequently (62%) than those involving members of the public (44%). 5. Thirty-six per cent of those involved in a 'confirmed' poisoning incident were working with a pesticide or were in close proximity to the operator; 41% were on private property adjacent to a field being sprayed and a further 23% involved those walking, cycling or jogging past a sprayed field.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗