A prospective study of the effects of ultralow volume (ULV) aerial application of malathion on epidemic Plasmodium falciparum malaria. III. Ecologic aspects.

The effects of aerial ultralow volume (ULV) malathion on selected species of nontarget animals in Haiti are reported. Mortality of certain groups of insects such as bees, flies, beetles, and butterflies was observed immediately following spray application. Minor fish mortality occurred only in shallow water exposed to direct spray. The brain acetylcholine esterase levels of living fish, tree lizards, birds and bats collected from treated areas were not significantly reduced. No ill or dead animals, besides the few fish, were seen even when maximum exposure occurred. Only minor changes in the feeding behavior of some insectivorous birds were observed. The relative bird density decreased substantially for only one species during the study, and other factors besides treatment were considered to be the reasons for the decline. Aerial applications of ULV malathion at dosages sufficient to dramatically reduce anopheline populations did not significantly affect nontarget vertebrates in this tropical environment.

Rib fractures in athletes.

Rib fractures are the most common serious injury of the chest. They occur most commonly in the middle and lower ribs with blunt trauma, and also with direct force to a small area of the chest wall and violent muscle contractions. Diagnosis is generally not difficult. The athlete should have a chest x-ray to confirm the diagnosis. Differential diagnosis includes severe rib contusion, costochondral separations, muscle strains and pneumothorax. If no internal problems exist, treatment consists of ice, NSAIDs, analgesics and a rib belt or tape. Healing should be well on its way before a return to sports. Fractures of the first 4 ribs or the last 2 ribs, multiple fractures and flail segments are less benign than other fractures, and may result in injury to surrounding structures. First rib and floating rib fractures are uniquely athletic fractures; they are avulsion fractures caused by a sudden vigorous contraction in different directions of pull.

The effect of anabolic steroids on the biomechanical and histological properties of rat tendon.

Twenty-four male rats were divided into four groups, with anabolic steroids and exercise as variables. Biomechanical tests and histological evaluations were performed. The results of the biomechanical tests suggested that anabolic steroids produce a stiffer tendon, which fails with less elongation. The energy at the time when the tendon failed, the toe-limit elongation, and the elongation at the time of the first failure were all affected significantly. Changes in the force at failure were not statistically significant. No alterations of structure were noted when the specimens were viewed with light microscopy. Alterations of the sizes of the collagen fibrils were noted on electron microscopy.

Gas chromatographic method for determination of fenitrothion in technical and in emulsifiable concentrate and water-dispersible powder formulations: collaborative study.

A variety of column packings and internal standards were evaluated to determine the most satisfactory system to use in a gas chromatographic (GC) method for analysis of fenitrothion, technical and formulations. Fenitrothion and the most closely related isomer, O,O-dimethyl O-(4-methyl-3-nitrophenyl) phosphorothioate, were resolved on columns packed with OV-210 and with polyphenyl ether, 6-ring (PPE-6R). A method based on the separation of fenitrothion on a PPE-6R column with fluoranthene as internal standard was selected for use in a limited collaborative trial and later for use in a full-scale collaborative trial with 21 collaborators participating. Each collaborator was furnished matched pairs of samples of technical fenitrothion, emulsifiable concentrate, and water-dispersible powder. The coefficients of variation (CV) for the paired samples were 1.02, 1.11, and 1.01, respectively, for technical fenitrothion, emulsifiable concentrates, and water-dispersible powders. Data are also presented for an alternative method in which compounds are separated on an OV-210 column with dibutyl sebacate as the internal standard. The method has been adopted official first action.

Evaluation of liquid chromatographic methods for analysis of chlorphoxim formulations.

Liquid chromatographic (LC) methods for determination of active ingredient in chlorphoxim formulations have been developed independently by Bayer AG and the Centers for Disease Control (CDC). Both methods specify separation on a silica gel column. The Bayer method uses a 5% solution of tetrahydrofuran in hexane as the eluting solvent and quantitates results on the basis of an external standard. The CDC method uses a 5% solution of ethyl acetate in hexane as the eluting solvent and uses 4-fluorophenyl sulfone as an internal standard. The 2 methods were compared by replicate analyses of samples of chlorphoxim technical and water-dispersible powder and emulsifiable concentrate formulations. The precision of both methods was acceptable.

Partition chromatographic separation of pesticide residues from fats.

A simple, rapid, and efficient partitioning column consisting of acetonitrile on Florisil has been developed for the separation of pesticides from fish, beef, and butter fat. The efficiency of the cleanup column is between 97 and 100%. Nine pesticides having partition coefficients between n-hexane and acetonitrile of less than or equal to 0.05 were satisfactorily separated from fat with good recoveries. When the column was used to clean up temephos in a fish extract, 99.91% of the fat was eluted with 20 ml n-hexane with no loss of the pesticide.

Synovial chondromatosis of the temporomandibular joint presenting as a parotid mass: possibility of confusion with benign mixed tumor.

Synovial chondromatosis is a rare metaplastic disorder of synovium in which cartilaginous nodules are produced within joint spaces. An unusual case involving the temporomandibular joint, with extension of the lesion beyond the joint capsule into the parotid gland, is described. The patient had a history of previous superficial parotidectomy for a "benign mixed tumor." Review of the histologic features revealed both lesions to be identical. The reason for confusion between the two diagnoses is discussed.

Liquid chromatographic and spectroscopic characterization of pentamidine isethionate and impurities in bulk drug and injectables.

A liquid chromatographic (LC) method is described for evaluating purity of pentamidine isethionate (PI), a life-saving drug used in the treatment of Pneumocystis carinii pneumonia, which is a leading cause of death in persons with acquired immunodeficiency syndrome (AIDS). Six potential impurity compounds were synthesized to test the selectivity of the chromatographic system and to permit quantitation of impurities in various lots of PI products. The drug and impurities were separated with gradient elution on a cyano-bonded LC column. The analytic system provided information on the identities and levels of impurities in early experimental lots of PI. These results assisted the manufacturer in altering reaction conditions and purification procedures to ensure that succeeding lots were within the specification limits, i.e., no more than 0.4% of any single impurity or 0.7% of total impurities found in the final product.

Studies on the mechanism of DDT-resistance in Culex pipiens fatigans.

Since the appearance of DDT-resistance in houseflies in 1947, over 30 mosquito species have developed resistance to this and other commonly used insecticides. Much knowledge has been gained concerning the mechanism of resistance in insects but, in general, this phenomenon cannot be explained in terms of a single factor common to all resistant species.Enzymic detoxication of DDT to DDE has been found in the study reported to be a major factor in the resistance of several mosquito species, particularly Aedes aegypti. However, such correlation could not be established in a highly DDT-resistant strain of Culex pipiens fatigans originating in Delhi, India. Furthermore, resistance of the latter strain to o-chloro-DDT and o,p-DDT cannot be attributed to a detoxication process since these compounds are refractory to dehydrochlorination both in vivo and in vitro. Quantitative data on metabolism of DDT derivatives are given and other possible mechanisms of resistance are discussed.

Storage and analysis of samples of water, fish, and mud from environments contaminated with abate.

Methods for extraction, cleanup, and analysis of samples of water, mud, and fish containing trace quantities of Abate have been developed. Water was extracted by high-speed stirring of 10 ml of hexane in a 300-ml sample. The extracts were evaporated and analyzed by gas chromatography with a limit of detection of 0.00003 ppm. Dried mud samples were extracted by shaking with acetone. An aliquot of the acetone extract was diluted with water and the Abate extracted into 10 ml of hexane by high-speed stirring. The extracts were analyzed by gas chromatography. Fish were extracted with methylene chloride, cleaned up on a silica gel column, and analyzed by gas chromatography. The limit of sensitivity of the methods for mud and fish was found to be 0.001 ppm. Fish samples were stored for 3 weeks in 10% formalin containing 5% sodium thiosulfate without significant loss of Abate residues. A biological magnification of greater than 100 was observed in fish exposed to Abate for 16 hr at concentrations of 0.02 and 0.002 ppm.

Gas-liquid chromatographic determination of chlorphoxim residues in water and fish by in-block methylation.

A gas-liquid chromatographic method has been developed for the analysis of residues of chlorphoxim, 2-chloro-alpha ((diethoxyphosphinothioyl)oxy)imino)-benzeneacetonitrile, in water and fish. The method is based on the in-block methylation of chlorphoxim with 0.01M trimethylanilinium hydroxide in methanol. The derivative, O,O-diethyl O-methyl phosphorothioate, was determined quantitatively by using a flame photometric detector specific for phosphorus. The in-block reaction is 70% efficient. Water samples were extracted with hexane; fish were extracted with methylene chloride and cleaned up on an acetonitrile-hexane partition column. Recoveries from water and fish samples spiked with chlorphoxim averaged 86.3 and 80.4%, respectively. Limits of detection were 10.0 ppb for 5 g samples of fish and 0.10 ppb for 300 ml water samples.

The toxicological properties of impurities in malathion.

During a malaria eradication programme in Pakistan in 1976, out of 7,500 spraymen, 2,800 became poisoned and 5 died. The major determinant of this poisoning has been identified as isomalathion present as an impurity in the malathion. It seems almost certain that the isomalathion was produced during storage of the formulated malathion. The quantitative correlation found between isomalathion content and toxicity of many field samples of malathion has been confirmed by an examination of mixtures of pure compounds. Addition of known amounts of isomalathion to technical malathion indicates that other active substances are present. These impurities have been identified (trimethyl phosphorothioates) and have been shown to behave like isomalathion in potentiating the toxicity of malathion. Some preliminary work on their toxicological properties is reported. The mechanisms involved in the potentiation of the toxicity of malathion are discussed.