Manganese in gasoline. Council on Scientific Affairs, American Medical Association

This report responds to a resolution that asked the American Medical Association (AMA) to take action to reduce potential health risks from the use of methylcyclopentadienyl manganese tricarbonyl (MMT) in gasoline. Information for this report was derived from a search of the MEDLINE database and references listed in pertinent articles, as well as through communications with medical and public health experts. Based on this information, the AMA Council on Scientific Affairs determined that there is insufficient scientific evidence to assess the public health impact of MMT use. While limited evidence indicates that general-population exposures to manganese from the use of MMT in gasoline are low, more research is needed to determine possible health effects from long-term, low-dose exposures to MMT and its combustion products. Until such data are available, educational and informational strategies should be developed to improve public awareness of the health and environmental issues surrounding MMT use.     

Identifying patients at low risk of death from cardiac failure after operation for postinfarct ventricular tachycardia

BACKGROUND: In unselected patients, cardiac failure accounted for most deaths after antiarrhythmic operation (ER) for postinfarction ventricular tachycardia (VT). This study aimed to determine whether patients at low risk of this outcome could be predicted from a retrospective analysis of variables from 100 consecutive ER patients. METHODS: Thirteen variables suggested by other researchers as predictive of outcome were analyzed. At the time of study, ER was the only therapy available for drug refractory VT. RESULTS: Only emergency ER, wall motion score less than 3 and Killip classification were significantly related to death from cardiac failure. The lack of correlation between emergency ER and variables of ER timing, VT less than 24 hours of ER or VT type implies that the need for emergency ER is also related to ventricular dysfunction. Multivariate analysis identified a group at particularly low risk of death with a specificity of 95%. CONCLUSIONS: Patients at low risk of death after ER can be identified prospectively. In the implantable cardioverter defibrillator era, elective ER is best reserved for such patients. Emergency ER may still be justified in younger patients without comorbidity who will die of VT without it.     

Aneurysms complicating pulmonary autograft procedure for aortic valve replacement

Aneurysm formation in the left ventricular outflow tract related to the proximal end of the pulmonary autograft after the Ross procedure was present in 2 patients. Both occurred late after operation and were associated with prolapse of a leaflet of the autograft and significant regurgitation. Both were repaired with no immediate complications. There was no evidence of infection at time of operation. The probable mechanisms underlying this complication and the possibilities of avoiding it are discussed.     

Effects of low-dose isoflurane on saccadic eye movement generation

The effects of 0.15% quasi-steady-state end-tidal isoflurane on two saccadic eye-movement tests were examined in five volunteers using a newly devised computer-based recording system. The tests were saccadic latency and a countermanding task, the latter being an indicator of the highest levels of conscious performance. A moving light-emitting diode target was displayed on a screen and in the saccadic-latency task the latency of eye movement to the target was measured. In all five subjects the latency increased with anaesthetic by an amount which varied from 8 to 45 ms. This result was significantly different (p < 0.05) from subjects without anaesthetic. In the countermanding task, the subject had to voluntarily inhibit movement to the target. Again anaesthetic increased the latency of response, which varied from 6 to 33 ms. This result was significantly different (p < 0.05) from subjects without anaesthetic. In these studies it appeared that two tasks, one a simple latency test and the other, the countermanding task, requiring higher cortical processing were equally impaired at subanaesthetic concentrations of isoflurane.     

Role of inter-α-inhibitor and its related proteins in urolithiasis. Purification of an inter-α-inhibitor related protein from the bovine kidney

Urine contains several macromolecules that inhibit calcium oxalate (CaOx) crystallization. Among them is bikunin, the light chain of most of the inter-α-inhibitor (IαI) family of glycoproteins. This study aimed to verify whether bikunin and other members of the IαI family are synthesized in the kidneys or derived exclusively from the plasma. Proteins extracted from homogenized bovine kidney were applied successively to three chromatographic steps on DEAE-Sephacel, Sephacryl S-300, and Mono Q column. The inhibitory activity was assayed using a CaOx crystallization system. The presence of IαI-related proteins was determined by␣electrophoresis and Western blotting. The results showed that kidney extract contained a 125-kDa protein that cross-reacted with anti-IαI antibodies. This protein inhibited CaOx crystallization efficiently. According to its molecular weight and immunoreaction with anti-IαI antibody, the 125-kDa protein could be pre-α-inhibitor. The latter is known to encompass a heavy chain and bikunin, which may explain its inhibitory activity against CaOx crystallization. Consequently, we hypothesize that kidneys may produce some IαI-related proteins that are involved in the inhibition of stone formation. Received: 18 February 1998 / Accepted: 9 July 1998     

Household members of hepatitis C virus-infected people in Hafizabad, Pakistan: infection by injections from health care providers

Household members of people with hepatitis C are at increased risk of HCV infection. The prevalence and routes of transmission of HCV to household members in Hafizabad, Pakistan were investigated. Household members of 24 index cases were given a risk factor questionnaire, tested for HCV infection, and the risk factors between the infected and uninfected were compared. Twelve of 74 household members (16.2%) were seropositive for HCV antibody. This was 2(1/2) times the rate of infection in the general population (OR = 2.8; P = 0.01). None of the routes of transmission studied within the household was associated with an increased risk. Household members who received more than 4 injections per year were 11.9 times more likely to be infected than those who had not (P = 0.016). In Hafizabad, the greatest risk for HCV infection to household members of infected people is injections given by health-care workers rather than household contact with infected persons.     

Nutritive value of various breads in Saudi Arabia

The nutritive value of nine Saudi breads prepared from wheat, millet and corn were measured chemically by proximate, minerals and vitamins analyses. On fresh weight basis, the bread contained 26.4-44.7% moisture, 6.6-10.4% protein, 0.4-2.4% fat, 40.2-60.6% available carbohydrates, 1.8-5.7% dietary fibre, 0.6-2.4% ash and 190-273 Kcal (metabolizable) per 100 g. All the breads were low in Ca (2.2-12.5 mg/100 g), P ranged from 41.9-320.8, Na 83.2-794.6, K 0.7-224.2 and Fe 1.6-7.8 mg/100 g. The contents of vitamin A (RE), thiamin and riboflavin ranged from 0-145 micrograms, 0.01-0.26 mg, 0.02-0.13 mg/100 g respectively. The bread contributed 12-18, 2-8 and 77-84% of the total food energy from protein, fat and carbohydrates respectively. Wheat bread (355 g/head/day) provided 45 and 61% of energy and protein requirements respectively at national level per person per day.     

Iodine deficiency disorders in Bangladesh

An extensive iodine deficiency disorders survery was conducted in Bangladesh in 1993 to assess the latest iodine nutriture status of the country. The clinical variables of the survey were goitre and cretinism, and the biochemical variable was urinary iodine. The “EPI-30 cluster” sampling methodology was followed for selecting the survey sites. In each survey site, the study population consisted of boys and girls, aged 5–11 years, and men and women, aged 15–44 years, in about equal populations. the total number of survey sites was 78 and the total number of respondents was 30 072. The total number of urine samples was 4512 (15% sub-sample). The current total goitre rate (grade 1+grade 2) in Bangladesh is 47.1% (hilly, 44.4%; flood-prone, 50.7%; and plains, 45.6%). The prevalence of cretinism in the country is 0.5% (hilly, 0.8%; flood-prone, 0.5%; and plains, 0.3%). Nearly 69% of Bangladeshi population have biochemical iodine deficiency (urinary iodine excretion [UIE]<10 mg/dl) (hilly, 84.4; flood-prone, 67.1%; and plains 60.4%). Women and children are more affected than men, in terms of both goitre prevalence and UIE. The widespread severe iodine deficiency in all ecological zones indicates that the country as a whole is an iodine-deficient region. Important recommendations of global interest are made from the experience of the survey. An erratum to this article is available at .     

Hydrolysis and photolysis of hexachlorocyclopentadiene

The radioactivity on adding ¹⁴C-Hexachlorocyclopentadiene (Hex) to water (7 7gmg/L) decreased by 18% on Day 2 and by 31 to 55% by Day 42. On Day 42, the radioactivity remaining in water consisted of apolar (petroleum ether-extractable), polar (ethyl acetate-extractable), and hydrophilic hydrolysis products with Hex amounting to only 8% of the total radioactivity. The time for Hex to reach 50, 10, and 5% of its initial concentration was estimated to be about 4, 27, and 40 days, respectively. The hydrolysis rate constant compared to 4×10³ hr^–1 as reported in literature. The apolar radioactivity (25% of total) consisted of Hex and a major product as judged by gas chromatography (GC). The polar products resolved into 10 and hydrophilics into 14 different compounds as examined by thinlayer chromatography.The photolysis of Hex in acetone occurred very rapidly (t_1/2=<1 day) with no trace of Hex after 15 days. Most of these products were more polar than Hex as examined by GC. These products on thin-layer chromatography (TLC) separated into two major zones. Further TLC of each of these zones showed products of one zone to resemble those of aqueous hydrolysis. The other zone represented apolar products which resolved into three peaks by HPLC, the major one of these appeared to have an empirical formula of C₆Cl₇O (m/e=408) as analyzed by GCMS.The 8-h photolysis products' mixture had an LT₅₀ to goldfish Carassius auratus of 22 h compared to 15 h for Hex. The 96-h LT₅₀ value of the 15-day photolysis products' mixture was 2,300 compared with 119 g/L for Hex. Thus, Hex in water as well as on exposure to light breaks down to less toxic products.