Malathion-resistant Tribolium castaneum has enhanced response to oxidative stress, immunity, and fitness

Many cases of insecticide resistance in insect pests give resulting no-cost strains that retain the resistance genes even in the absence of the toxic stressor. Malathion (rac-diethyl 2-[(dimethoxyphosphorothioyl)sulfanyl]succinate) has been widely used against the red flour beetle, Tribolium castaneum Herbst. in stored products although no longer used. Malathion specific resistance in this pest is long lasting and widely distributed. A malathion resistant strain was challenged with a range of stressors including starvation, hyperoxia, malathion and a pathogen to determine the antioxidant responses and changes to some lifecycle parameters. Adult life span of the malathion-specific resistant strain of T. castaneum was significantly shorter than that of the susceptible. Starvation and/or high oxygen reduced adult life span of both strains. Starving, with and without 100% oxygen, gave longer lifespan for the resistant strain, but for oxygen alone there was a small extension. Under oxygen the proportional survival of the resistant strain to the adult stage was significantly higher, for both larvae and pupae, than the susceptible. The resistant strain when stressed with malathion and oxygen significantly increased catalase activity, but the susceptible did not. The resistant strain stressed with Paranosema whitei infection had significantly higher survival compared to the susceptible, and with low mortality. The malathion resistant strain of T. castaneum showed greater vigour than the susceptible in oxidative stress situations and especially where stressors were combined. The induction of the antioxidant enzyme catalase could have helped the resistant strain to withstand oxidative stresses, including insecticidal and importantly those from pathogens. These adaptations, in the absence of insecticide, seem to support the increased immunity of the insecticide resistant host to pathogens seen in other insect species, such as mosquitoes. By increasing the responses to a range of stressors the resistant strain could be considered as having enhanced fitness, compared to the susceptible.

Oviposition deterrent activities of Pachyrhizus erosus seed extract and other natural products on Plutella xylostella (Lepidoptera: Plutellidae)

An extract of a rotenone-containing plant yam bean, Pachyrhizus erosus (L.) Urban, seeds was tested against the diamondback moth, Plutella xylostella (L.) in a greenhouse to determine its potential as an oviposition deterrent and compared with coumarin and rutin, known as diamondback moth oviposition deterrent compounds, rotenone, and an extract of Peruvian cube root, at a concentration of 0.5% (w/v). Oviposition deterrent index (ODI) was used to determine effects of extracts or compounds in inhibiting oviposition of diamondback moth. Coumarin showed a stronger deterrent effect than the yam bean seed extract with a higher ODI value. On the contrary, rotenone, rutin, and the cube root extract, containing 6.7% (w/w) of rotenone, showed no significant deterrent effects having low or negative ODI values, suggesting that the deterrent effect of the yam bean seed extract is not due to rotenone content of the yam bean seeds. The extract of yam bean seed and coumarin partially deterred the moth from laying eggs on treated leaves in a concentration-dependent manner. The effective concentration for 50% deterrency of coumarin and the yam bean seed extract were 0.11 and 0.83% (w/v), respectively. However, the yam bean seed extract showed a residual deterrent effect on the moth even at 3 d after the treatment and is probably because of its low volatile nature. A long-term deterrency of the yam bean seed extract is an advantage over coumarins. Both the yam bean seed extract and coumarin deterred diamondback moth from laying eggs in total darkness, indicating their nonvisual deterrent effect. This made the extract an effective deterrence to diamondback moth in light and in darkness. To conclude, this study revealed the potential of the crude extract of the yam bean seed to prevent diamondback moth from ovipositing on its plant host.

Modeling pesticide leaching and dissipation in a mediterranean littoral greenhouse

The one-dimensional chromatographic flow model PEARL was used to simulate the movement of the insecticide imidacloprid and the fungicide procymidone through a greenhouse soil. The model was parametrized using measured and literature values of soil hydrological parameters. Soil water movement and soil temperature were reasonably well described by the model. The ability of PEARL to simulate the fate of imidacloprid and procymidone following four applications of each compound was evaluated against greenhouse data. Simulated imidacloprid residues in the 0-10 cm layer were in good agreement with measured data. Below 10 cm, the model overestimated imidacloprid remaining following the spray applications, whereas simulated residues following the chemigation applications were in reasonable agreement with measured data. Simulated residues of procymidone in the 0-10 cm layer were in general agreement with measured values. In the 10-20 cm layer, peaks in simulated concentrations occurred later than observed in the greenhouse. Predictions of procymidone residues below 20 cm were poor and underestimated compared to the measured data. For both pesticides, discrepancies between modeled and measured data in the 10-20 cm layer were attributed to the drip irrigation method used in the greenhouse. The model was unable to satisfactorily predict pesticide movement from the soil surface by irrigation water unless the scenario was modified to reflect the localized pattern of water application. Scenario analysis indicated that air boundary layer thickness is a key parameter for readily volatilized pesticides such as procymidone. This is of particular relevance to the greenhouse environment, where the boundary layer thickness may be greater than that in outdoor conditions.

Sorption behaviour of oxadiazon in tropical rice soils

The soprtion behaviour of a pre-emergent herbicide, oxadiazon (5-tert-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2 (3H)-one) was investigated in tropical rice soils using a batch equilibrium method. There is no information available on the fate of oxadiazon in Bangladeshi soils; Bangladesh rice soil is a unique environment. The experiment was performed using radiolabelled (14C) oxadiazon. The sorption and desorption isotherm of oxadiazon was described using the Freundlich equation. L-type sorption isotherms were observed. The correlation coefficient (r2) was 0.995 to 0.997 and the linearity of the slope was in the range 0.96-1.07. Sorption of oxadiazon was related to organic carbon. Sorption of oxadiazon by soil was a rapid process; sorption kinetics indicated that most of the sorption occurred within two hours. Changes in sorption of oxadiazon by soils was investigated by repeated application. Sorption after the first cycle was in the range 81-92% whereas sorption capacity decreased in the following cycles.

Improved survival in primary nonmetastatic pediatric osteosarcoma of the extremity

A prospective study using a dose-intensified neoadjuvant intra-arterial chemotherapy regimen was designed to improve survival rates of young patients with primary, nonmetastatic osteosarcoma of the extremity. Arteriography was implemented to individualize duration of therapy by serially assessing change in tumor neovascularity. Intravenous doxorubicin and intra-arterial cisplatin were administered repetitively at 3-week intervals until > or = 90% reduction in tumor neovascularity was achieved. Surgery was delayed until this good arteriographic response was documented. After resection, prediction of tumor neovascularity was compared with tumor necrosis. Since 1987, 62 eligible patients younger than 22 years old were treated with an average of four neoadjuvant courses. Toxicities were manageable. Fifty-four (87%) patients had a good histologic response. The rate of limb preservation surgery was 93.5% (58/62). Accuracy and sensitivity of serial arteriography in predicting histologic response were 92% and 98% respectively, and greatly assisted surgical planning. With an average followup of 91 months, estimated Kaplan-Meier survival at 10 years was 93% and event-free survival was 86%. Osteosarcoma survival rates were significantly improved by the use of this regimen compared with previously reported results. Serial arteriography succeeded in individualizing duration of neoadjuvant therapy and led to a higher rate of good histologic response.

LEVEL OF EVIDENCE

Therapeutic study, level II-1 (prospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.

Comparison of two methods for estimation of soil sorption for imidacloprid and carbofuran

Predicting the fate and transport of pesticides in soil environment is an important issue especially in understanding and modelling of the environmental behaviour of pesticides. Classical batch sorption method often has been identified as insufficient to derive the actual extent of sorption. In this study, the batch equilibrium method was compared to the centrifugation method, which can permit measurement of sorption under more natural conditions. The results of the comparison of the batch with the centrifugation method for imidacloprid and carbofuran pesticides indicate that the batch method overestimates sorption in comparison to the centrifugation method. These results are in agreement with others, which use high soil:solution ratios with batch and those that used the centrifugation method.

Characterization of the sorption of an anthranilate fungicide in soil using thermal analytical and mineralogical techniques

The sorption of pesticides to soil particles has implications for their distribution and fate in the soil environment. A batch equilibrium technique was used to investigate sorption of the fungicide AEC623892 to intact and hydrogen-peroxide-treated whole soils and several particle-size fractions isolated from them. Sorption of AEC623892 to the soil as a whole was low. K(f oc) values measured in the whole soils were 169.2 and 41.9 ml g(-1) for Soil A and Soil B respectively. The highest values of K(f oc) were measured in soil particle-size fractions <53 microm (266.5 ml g(-1) in the 2-20 microm fraction of Soil A; 471.9 ml g(-1) in the 20-53 microm fraction of Soil B). Sorption was most irreversible in the 2-20 microm fractions. Overall, treatment of soil particle-size fractions with hydrogen peroxide resulted in lower values of K(f oc) (112.3 ml g(-1) in Soil A whole soil and 30.9 ml g(-1) in Soil B whole soil). In both soils, the maximum sorption among hydrogen-peroxide-treated samples was observed in the <2 microm fraction (166.6 and 311.0 ml g(-1) for Soil A and Soil B, respectively). Investigation of the mineralogical composition of the soils suggested that the clay mineralogy (dominated by kaolinite and illite) is less likely to account for the differences in sorption observed than differences in the characteristics of the soil organic matter. Thermal analysis of the different soil fractions indicated that hydrogen peroxide treatment preferentially removed aliphatic fractions of organic matter, but had less effect on lignin-like, aromatic fractions.

Low molecular weight polylactic acid as a matrix for the delayed release of pesticides

Low molecular weight polylactic acid (LMW PLA) was used as a matrix to formulate biodegradable matrix granules and films with bromacil using a melt process. The compatibility of the PLA with bromacil was evaluated. The release characteristics of the formulations were investigated in vitro. The degradation and erosion of the formulations were monitored by pH and gravimetric analysis during the course of release. Various granules and films had similar biphasic release patterns, a delayed release followed by an explosive release. The release rates were independent of bromacil content in the matrix, but varied with the geometry of matrices. The mechanisms of diffusion and erosion were involved in the release. The delayed release of the formulations was dominantly governed by the degradation and erosion of PLA. LMW PLA underwent bulk erosion. LMW PLA-based matrix formulations could thus be useful for the application of pesticides to sensitive targets such as seed treatment.

A novel therapeutic strategy for Ehlers–Danlos syndrome based on nutritional supplements

Ehlers-Danlos syndrome is a rare disorder, comprising a group of related inherited disorders of connective tissue, resulting from underlying abnormalities in the synthesis and metabolism of collagen. This proposal is specifically concerned with Ehlers-Danlos syndrome classic type (formerly Types I-III), which is characterized by joint hypermobility and susceptibility to injury/arthritis, skin and vascular problems (including easy bruising, bleeding, varicose veins and poor tissue healing), cardiac mitral valve prolapse, musculo-skeletal problems (myopathy, myalgia, spinal scoliosis, osteoporosis), and susceptibility to periodontitis. No treatment is currently available for this disorder. The novel aspect of this proposal is based on: (i) increasing scientific evidence that nutrition may be a major factor in the pathogenesis of many disorders once thought to result from defective genes alone; (ii) the recognition that many of the symptoms associated with Ehlers-Danlos syndrome are also characteristic of nutritional deficiencies; (iii) the synergistic action within the body of appropriate combinations of nutritional supplements in promoting normal tissue function. We therefore hypothesize that the symptoms associated with Ehlers-Danlos syndrome may be successfully alleviated using a specific (and potentially synergistic) combination of nutritional supplements, comprising calcium, carnitine, coenzyme Q(10), glucosamine, magnesium, methyl sulphonyl methane, pycnogenol, silica, vitamin C, and vitamin K, at dosages which have previously been demonstrated to be effective against the above symptoms in other disorders.

Comparison of antioxidant activity in commercial Ginkgo biloba preparations

AIM

To compare the relative levels of antioxidant activity in vitro in Ginkgo biloba samples (in tablet or capsule form) from different commercial suppliers, to determine whether some brands may be more efficacious in their potential to increase endogenous antioxidant activity, and thereby counter oxidative stress related disorders.

DESIGN

Antioxidant activity of the above sample extracts was determined in vitro against the ABTS.(+) (2-2'-amino-bis-3-ethylbenzthiazoline-6-sulfonic acid) radical, relative to Trolox (water-soluble vitamin E analogue) antioxidant standards, using an established assay procedure.

OUTCOME MEASURES

The relative antioxidant activity of G. biloba sample extracts was expressed in terms of millimoles per liter of Trolox equivalent (TE) for the initial extract, micromol TE per whole tablet, nmol TE per mg tablet, and nmol TE per mg ginkgo content.

RESULTS

Data (as mean +/- standard deviation (SD) from 4 separate estimations) obtained in this study showed a considerable variation (approximately 50-fold) in the level of antioxidant activity in preparations from different suppliers, particularly when compared on an equivalent (i.e., nmol TE/mg ginkgo) basis. Of the 18 products investigated, the highest level of antioxidant activity (whether expressed as micromol TE per whole tablet or nmol TE/mg ginkgo) was obtained for Pharma Nord Bio-Biloba (Pharma Nord, Morpeth, UK) tablets (p < 0.05, Dunnett's statistical test).

CONCLUSIONS

Some of the apparent variation in antioxidant activity of the various products investigated can be accounted for in terms of the physical nature of the G. biloba (i.e., dried leaf powder or standardized concentrated extract) used in tablet formulation. However, even when comparing products based on concentrated extract, the data demonstrated that there is still a considerable variation in antioxidant activity. Presumably this may result from differences in the manufacturing process between suppliers, which in turn may limit the efficacy of these preparations in the prevention or treatment of disease.

The use of a closed expandable prosthesis for pediatric sarcomas

PURPOSE

The purpose of this paper is to review our experience with a non-invasive expandable prosthesis for skeletally immature patients following limb-salvage for malignant tumors about the knee.

MATERIALS & METHODS

Between 1998 and 2002, Repiphysis prostheses (Wright Medical Technology, Memphis, Tenn.) were implanted in 18 patients. 16 patients had at least 12 months follow-up. There were 10 males and 8 females. The diagnosis was Stage IIB osteosarcoma in all patients. Sites included femur 14, and 4 proximal tibias. The average age was 10.7 years (range 8-16); the average age for males was 12 years and females, 9 years. Fifteen of the prostheses were implanted at the time of surgical resection and the remainder was conversions of previous surgery.

RESULTS

Follow-up averaged 24.8 months (range 12-47). Fourteen patients have undergone a total of 58 lengthening procedures. Average expansion 38 mm per patient (range, 10-76 mm). An average of 8.5 mm per lengthening procedure. There was only one failure to lengthen. ISOLS functional scores averaged 83.5%. For those with a current functional prosthesis, the ISOLS score averaged 94%. Three patients have reached maximal expansion and converted to a conventional prosthesis. There were complications in 7 patients: 2 expandable component fractures, 1 femoral component fracture, 2 stem fractures, 1 stem loosening and 1 deep infection. Of the two expandable component fractures, 1 patient reached full expansion and was converted to an endoprosthesis. The femoral component fracture and 2 stem fractures were revised to a new prosthesis 13 months post-op and are functioning well. The 1 loose stem was revised to an APC.

CONCLUSIONS

The Repiphysis prosthesis utilizes energy stored in a spring that is held compressed by a locking mechanism. Controlled release of the locking mechanism via an external electromagnetic field allows for lengthening of the device. In our early experience, the functional results were excellent similar to conventional modular devices. Complications should be anticipated but are salvageable. This device allows limb salvage in pediatric patients when amputation would be otherwise chosen.

Controlled release of the herbicide, fluometuron, from matrix granules based on fractionated organosolv lignins

An organosolv lignin and several of its fractions were used to prepare controlled release matrix granules with fluometuron using a melt process. Release profiles of fluometuron from these granules and a commercial granular formulation were studied in vitro. The release rates of fluometuron were considerably reduced from all lignin-based granules as compared to the commercial formulation. The release rates markedly varied with the lignin fraction used in the fluometuron-lignin matrix systems with the corresponding times for 50% release (T(50)) values ranging from 2.37 to 11.2 days. The variation in release rate of fluometuron was related to the high proportion of low molecular weight lignin and its associated water soluble lignin in the lignin-based granules, in terms of the hydrophobicity of matrix, the content, and release rate of soluble lignin. The release kinetics were fitted to the generalized model for up to 60% release of fluometuron; the kinetics of fluometuron were of the anomalous type for all matrixes in which release rates increased following a delay.

Synergistic and antagonistic interactions of anticholinesterase terpenoids in Salvia lavandulaefolia essential oil

In vitro anticholinesterase activities of eight commercially available terpenoid constituents of Salvia lavandulaefolia have been investigated. These included 1,8-cineole, camphor, alpha-pinene, beta-pinene, borneol, caryophyllene oxide, linalool and bornyl acetate. Dose-dependent inhibition of acetylcholinesterase (AChE) by these chemical constituents was determined using the method of Ellman [Biochem. Pharmacol. 7 (1961) 88]. The IC50 value of 1,8-cineole was 0.06+/-0.01 mg/ml similar to that of the essential oil (0.05+/-0.01 mg/ml). Analyses of the expected inhibitions based on the prediction of a zero interactive response of a combination at its naturally occurring ratios were carried out in comparison with observed inhibition. Minor synergy was apparent in 1,8-cineole/alpha-pinene and 1,8-cineole/caryophyllene oxide combinations, with interaction indexes not exceeding 0.5. In contrast, a combination of camphor and 1,8-cineole was antagonistic with an interaction index of 2. A combination of all eight compounds was zero interactive. A combination of six constituents, excluding 1,8-cineole and camphor, was used to compare the method of expected response of a combination with a method of summation. These findings reveal that the inhibitory activity of the oil results from a complex interaction between its constituents, which produce both synergistic and antagonistic responses between the component terpenes. Understanding such interactions is important in comparing species on the basis of chemical composition.

Parameterisation, evaluation and comparison of pesticide leaching models to data from a Bologna field site, Italy

Effective prediction of pesticide fate using mathematical models requires good process descriptions in the models and good choice of parameter values by the user. This paper examines the ability of seven pesticide leaching models (LEACHP, MACRO, PELMO, PESTLA, PLM, PRZM and VARLEACH) to describe an arable field environment where sunflowers are grown in the Po Valley, northern Italy. Two pesticides were considered, aclonifen and ethoprophos. The models were evaluated in terms of their ability to reproduce field data of soil water content and pesticide residues in the soil and ground water. The evaluation was based on a combination of calibrated and uncalibrated runs. The results from the models were compared with each other to explore the differences between the models. The models varied in their ability to predict soil water content in the summer: the capacity models PRZM, PELMO and VARLEACH predicted less drying than MACRO, PESTLA, PLM and LEACHP. The models varied in their ability to simulate the persistence of the pesticides in the soil. Differences in the simulated pesticide degradation rate were observed between the models, due to variations in the simulated soil water content and soil temperature, and also differences in the equation linking degradation rate to soil water content. There were large differences among the predictions of the models for the mean leaching depth of ethoprophos. PRZM, PELMO, PESTLA and LEACHP all showed similar mean leaching depth to each other, whereas VARLEACH predicted lower ethoprophos mobility and PLM and MACRO predicted greater mobility. All the models overpredicted dispersion of ethoprophos through the soil profile, as compared to the field data. None of the models was able to simulate the field data of rapid leaching of pesticide to ground water except PLM after calibration of the percentage of macropores in the mobile pore space. More work is required in the parameterisation of macropore flow for those models that include this process.

Effect of gas-plasma sterilization on the osteoinductive capacity of demineralized bone matrix

The current study evaluated the effect of low-temperature hydrogen peroxide gas plasma sterilization on the osteoinductive capability of human demineralized bone matrix using a rat model. Twelve athymic rats received three separate implants consisting of steam-sterilized demineralized bone matrix (negative control), sterile-harvest demineralized bone matrix (positive control), and gas-plasma-sterilized demineralized bone matrix. A demineralized bone matrix pellet from each sterilization group was placed individually into one of three separate soft tissue pockets created in the epaxial musculature of each rat. All 12 rats were euthanized 9 weeks after implantation. Each implantation site was removed along with 0.5-cm normal tissue around the implant. Histologic examination was done on each implant site to determine the presence or absence of new bone, cartilage, or bone marrow elements. All 12 sterile harvest demineralized bone matrix sites histologically contained new bone elements, whereas none of the negative control or gas plasma sterilized demineralized bone matrix sites contained any of these same elements. The results of this study indicate that demineralized bone matrix sterilized with low-temperature, gas-plasma sterilization loses its osteoinductive capacity in a manner similar to that of steam-sterilized demineralized bone matrix, making low-temperature, gas- plasma sterilization unsuitable as a method of secondary sterilization of demineralized bone matrix.

The Phenix expandable prosthesis: early American experience

One of the major dilemmas in limb preservation in skeletally immature children involves the ability to maintain leg length equality. Many attempts have been made to design a prosthesis that could be expanded easily either nonoperatively or through a minor surgical procedure. Most of these designs have had mechanical difficulty or the lengthening procedure becomes a major surgical endeavor. The Phenix technology has been used in France for several years. The basic principle involves storage of energy in a spring which is maintained compressed by an original locking system. Once implanted, prosthetic lengthening is achieved via exposure to an external electromagnetic field that pilots the locking system and allows controlled release of the spring energy. Seven Phenix prostheses have been implanted in six patients. All patients had been treated for Stage II-B osteosarcoma. Six of the seven prostheses were implanted during revision procedures in salvage situations; one prosthesis was implanted during an index procedure. The surgical procedures were completed without complications. One patient sustained a fracture of the prosthesis in a fall and had an infection develop after implantation of the second prosthesis. Twenty-one expansions have been performed in six patients (mean lengthening at each procedure, 8 mm). There were no acute complications attributable to the lengthening procedure. Prosthetic expansions required an average of 20 to 30 seconds and were accompanied by very mild discomfort, if any. Most patients were given an oral analgesic either before or during the lengthening procedure. The Phenix prosthesis shows promise in handling the difficult problem of limb preservation in a growing child. Additional investigation is underway regarding limb lengthening and other dynamic applications.

The use of a surgical grade calcium sulfate as a bone graft substitute: results of a multicenter trial

In a prospective, nonrandomized, multicenter study, 109 patients with bone defects were treated with a surgical grade calcium sulfate preparation as a bone graft substitute. The calcium sulfate pellets were used in place of morselized cancellous bone graft for the treatment of patients with bone defects who usually would require grafting secondary to trauma, periprosthetic bone loss, tumor, or fusion. The calcium sulfate was used alone or mixed with other materials such as bone marrow aspirate, demineralized bone matrix, or autograft. The defects that were treated were contained and were not necessary for the stability of the bony structure. Radiographic and clinical data were collected at predetermined intervals for 12 months. At 6 months postoperatively, radiographic results for all patients showed that 99% of the calcium sulfate had been resorbed and 88% of the defect was filled with trabeculated bone. There were 13 complications; however, only four (3.6%) were attributable to the product. The results of a subgroup of 46 patients with benign bone lesions treated in the same manner are identical to the results of the overall study population. Surgical grade calcium sulfate pellets are considered a convenient, safe, and readily available bone graft substitute that yield consistent successful results.

Controlled release of a herbicide from matrix granules based on solvent-fractionated organosolv lignins

An organosolv (Alcell) lignin was fractionated with both sequential solvent-extraction and solvent-mixture precipitation using various organic solvent systems. The resulting fractionated lignins were used to prepare matrix granules with bromacil as a model compound using a melt process. The release rates of bromacil in vitro from the granular matrix system were influenced by both the lignin used as carrier and the solution fractionation. The variations in release rates were related to the high proportion of low-molecular-weight fraction and its associated water-soluble lignin in the fractionated lignins. Fickian diffusion was a predominant factor in controlling the release of bromacil from the matrix granules based on the low-molecular-weight fraction (L(fr1)). For the matrix granules based on the other fractionated lignins, the release of bromacil was of super-case II transport. The fine structure of the matrix granules before and after release was also studied. An unique release pattern of bromacil was observed for the matrix granules based on the low-molecular-weight fraction (L(fr1)), showing a fast release followed by zero-order release, which was a result of remarkable changes in the structure of the matrix granules during the course of release.

Unicameral bone cysts

Unicameral, or solitary, bone cysts are unusual tumors seen in the ends of long bones in skeletally immature persons. The etiology of these lesions is poorly understood. Various hypotheses have included dysplastic processes, synovial cysts, and abnormalities in the local circulation. Most patients present with a nondisplaced pathologic fracture, but occasionally cysts are found incidentally. Plain radiographs typically show a symmetric lesion with cortical thinning and expansion of the cortical boundaries. Once diagnosed, unicameral bone cysts continue to be a treatment dilemma. Traditional methods, such as prednisolone therapy, usually involve multiple anesthetics and injections and are associated with high recurrence rates. Major surgical procedures, such as wide exposure, curettage, and bone grafting, may be somewhat more effective, but still carry with them significant morbidity and recurrence rates. Newer techniques involving percutaneous grafting with allograft or bone substitutes or a combination of the two are promising in light of their low complication rate and lower reoperation rate.

Comparative effect of fenitrothion treatment on intracellular protease activities in insecticide-resistant and susceptible strains of Musca domestica L

In order to further elucidate the biochemical mechanisms responsible for insecticide resistance in insects, we have determined changes in the activity levels of a comprehensive range of proteolytic enzymes (cytoplasmic and lysosomal proteinases and peptidases, which play a key role in normal cell functioning) in fenitrothion-resistant (571ab) and susceptible (Cooper) strains of Musca domestica following in vivo exposure to the insecticide fenitrothion. Untreated insects of the resistant strain had significantly higher levels (20-100%) of activity for many protease types compared to the susceptible strain (whole body analysis). Exposure to fenitrothion resulted in further activity increases for most proteases at some point during the subsequent 24 h period in resistant strain insects; susceptible strain insects were also capable of similar increases in protease activities. We therefore suggest that it must be the combination of intrinsically higher protease levels (prior to pesticide exposure), together with the capacity to further increase protease activities following insecticide exposure, which is important in the mechanism by which proteases may confer survival advantages in insecticide resistant insects. We further speculate that this mechanism may involve increased supply of precursor amino acids from proteolytic degradation products to the intracellular pool, prior to de novo synthesis of detoxifying enzymes following insecticide exposure.

Bioassayed demineralized bone matrix and calcium sulfate: use in bone-grafting procedures

BACKGROUND AND AIMS

A combination product of bioassayed, demineralized bone matrix (AlloGro, AlloSource, Denver CO) and calcium sulfate pellets (OsteoSet, Wright Medical Technology, Arlington TN) was utilized in a prospective clinical study in 50 patients in need of bone-grafting procedures. It was proposed that the osteoinductive activity of the demineralized bone matrix combined with the osteoconduction and rapid dissolution of the calcium sulfate pellets would complement each other in promoting bone formation.

MATERIALS AND METHODS

The patients were evaluated clinically and radiographically at regular intervals post-operatively by an independent clinician. A total 10-point healing score was used to determine healing characteristics and progress. Fifty patients (24 males and 26 females) were treated for benign bone lesions (35), nonunion (11), osteomyelitis (3), and acute fracture (1). The average age was 33 years (range, 3-64 years). Lesions were located in the femur (16), tibia (15), humerus (7), and other sites (12).

RESULTS

The average length of follow-up was 14 months (range, 6-32 months). Forty-nine of 50 patients healed their lesions (98%), requiring an average time to heal of 11.8 weeks (range, 3-48 weeks). There were no graft-related complications.

CONCLUSIONS

The results of this preliminary clinical study suggest that a combination of bioassayed demineralized bone matrix and calcium sulfate is very effective in treating benign lesions of bone, as well as nonhealing fractures, which is comparable to grafting with autograft. Future studies have been undertaken utilizing this combination in all acute operative settings and fracture management situations.

Controlled release of aldicarb from lignin loaded ionotropic hydrogel microspheres

Aldicarb loaded microspheres of carboxymethyl cellulose, CMC, of various compositions were prepared with the crosslinking action of Al(III). Into these microspheres, lignin was introduced as a filler to further regulate the rate of release. The encapsulation efficiency was low (4.15-13.00%) due to the high water solubility of aldicarb. Release into aqueous media was quite rapid and almost complete within 24h. Initial stages of the release (60% of AS released) was investigated to determine the release mechanism and it was found that release from the microspheres was governed by Fickian diffusion. Among the various parameters, the ratio of lignin to CMC and aldicarb to CMC were found to be influential on the rate of release from the crosslinked CMC-lignin microspheres. The soil behaviour confirmed the delayed release effect of the controlled release formulation compared to Temik (a commercial preparation of aldicarb), especially when lignin was incorporated.

Comparison of proteolytic enzyme activities in adults of insecticide resistant and susceptible strains of the housefly M. domestica L

Intracellular proteolytic activity in a DDT-resistant and a susceptible strain of M. domestica was determined by assaying a comprehensive range of cytoplasmic and lysosomal enzymes. The resistant strain showed significantly higher protease activities in whole body, head, thorax, abdomen and gut homogenates compared to the susceptible strain. The activity of alanyl- and arginyl aminopeptidase from both strains increased substantially after topical treatment with DDT at 1, 2 and 3 h, suggesting an involvement of proteolytic enzymes in the induction of detoxifying enzymes, thus indicating a possible role of the intracellular proteolytic activities in the resistance mechanism.

Effect of Tri-O-cresyl phosphate (TOCP) on proteolytic enzyme activities in mouse liver in vivo

To develop a clearer understanding of the biochemical mechanisms of toxicity in higher animals, we determined the effect of four sublethal dosages (0.25 to 1.0 g/Kg) of organophosphate (OP), and of tri-ortho-cresyl phosphate (TOCP) on the activities of a representative range of cytoplasmic and lysosomal proteolytic enzymes in mouse liver in vivo. Administration of the lowest sublethal dosage of TOCP (0.25g/1Kg, 24 hours) resulted in significant inhibition (10 to 30% of control activity) of the cytoplasmic proteases tripeptidyl aminopeptidase and proline endopeptidase only. An increasing dosage of TOCP (1g/Kg for 7 days) resulted in significant inhibition (10 to 50% of control activity) of the cytoplasmic proteases alanyl aminopeptidase, leucyl aminopeptidase, tripeptidyl aminopeptidase, and proline endopeptidase, as well as the lysosomal proteases dipeptidyl aminopeptidase I and cathepsins B, D, and L. The activities of the cytoplasmic proteases arginyl aminopeptidase and dipeptidyl aminopeptidase IV, and of lysosomal proteases dipeptidyl aminopeptidase II and cathepsin H were not significantly altered following TOCP administration at this higher dosage. All of the above proteases are involved in the general process of intracellular protein turnover (common to all tissues), and may also have more specialized functions such as the processing of physiologically active hormonal peptides, and the processing of antigenic proteins in the immune response. Data obtained in the present study suggest that inhibition of the above enzymes by OP such as TOCP may represent a previously unrecognized toxicity hazard induced by the latter compound in higher animals.

Effect of pirimiphos-methyl on proteolytic enzyme activities in rat heart, kidney, brain and liver tissues in vivo

To elucidate whether pesticide toxicity in higher animals involves pesticide-induced dysfunction of the intracellular protein catabolic process, we have determined the effect in vivo of the organophosphate insecticide pirimiphos-methyl on the activities of representative protein catabolising cytoplasmic and lysosomal proteases (responsible for the various stages of the protein degradation cascade and essential for normal cell functioning) in heart, kidney, brain and liver target tissues in the rat. In liver tissue (the major site of pesticide metabolism), the activities of all of the cytoplasmic proteases investigated (alanyl-, arginyl-, leucyl aminopeptidases, dipeptidyl aminopeptidase IV, tripeptidyl aminopeptidase, proline endopeptidase) were significantly inhibited (by 20-40% of control activity) following administration of 10 mg pirimiphos-methyl/kg bodyweight, whereas of the lysosomal proteases investigated, only the activities of dipeptidyl aminopeptidase I and cathepsin D were significantly reduced (by 15-20% of control activity). In contrast, there was no insecticide-induced inhibition of protease activities in heart, kidney or brain tissues; some lysosomal enzymes (dipeptidyl aminopeptidase I, cathepsins L and D) showed significantly increased activities in these tissues (the reason for which remains to be determined). We conclude that the effect of pirimiphos-methyl on proteolytic enzyme activities differs in different target tissues, and that pirimiphos-methyl induced inhibition of proteases in liver tissue may represent a previously unrecognised toxicity hazard in higher animals.

Toxicity of microcystin-LR, isolated from Microcystis aeruginosa, against various insect species

Microcystin-LR (MC-LR), isolated from the cyanobacterium Microcystis aeruginosa Kuetzing emend. Elenkin strain CCAP 1450/4 was tested for biological activity against four species of insect and the invertebrate Artemia salina. The efficacy of pesticidal activity was compared with various insecticides. The 24 hr LD50 value for third instar diamond-backed moth, Plutella xylostella, on ingestion from a treated leaf surface was 1.0 micrograms cm2, compared with a 72 hr LD50 value for rotenone of 2.0 micrograms cm-2. The 24 hr LD50 values of MC-LR and malathion on intrathoracic injection into adult house flies (Musca domestica) were 0.5 and 3.7 mg kg-1, respectively. MC-LR had no effect on M. domestica when applied topically at dosages up to 32 mg kg-1. MC-LR and malathion gave 24 hr LD50 values of 4.7 and 13.1 mg kg-1, respectively when injected into third instar cotton leafworm (Spodoptera littoralis). In fourth instar cabbage white butterfly larvae (Pieris brassicae) MC-LR injected gave 24 and 48 hr LD50 values of 3.9 and 1.9 mg kg-1, respectively, whilst the 24 and 48 hr LD50 values for carbofuran were 0.4 and 0.3 mg kg-1, respectively. An immersion bioassay with 1-day-old brine shrimp larvae (Artemia salina) gave 24 hr LD50 values of 3.8 micrograms ml-1 for MC-LR and 1.8 micrograms ml-1 for carbofuran. MC-LR has appreciable insect toxicity, comparable to the three insecticides tested. The toxin look 24-48 hr to exert its full lethal effect in insects, much longer than the 1-3 hr it takes in mammals. The potential use of MC-LR as an insecticide is discussed.

Giant cell tumor of bone treated by curettage, cementation, and bone grafting

Giant cell tumor, a relatively rare, occasionally malignant tumor of bone, remains a difficult therapeutic problem for the orthopedic surgeon. Various treatment options, including curettage alone, curettage with bone grafting, radiation, and curettage with acrylic cementation have been utilized and reported. Therapeutic complications such as infection, recurrence, and loss of support of the articular surface have continued to plague the treatment of giant cell tumors. This article reports the results of 10 consecutive cases of giant cell tumor of bone treated by curettage and methyl methacrylate cementation, followed by bone grafting of the surface of the lesion with demineralized bone matrix to reconstitute the cortex at the site of the tumor. At an average follow up of 36 months, eight patients had an excellent functional result and two had a fair result as scored on the Musculoskeletal Tumor Society rating system. To date, there have been no tumor recurrences or metastases, and all patients have radiographic evidence of healing of the weight bearing cortical surface.

Metastatic disease of the femur

Metastatic involvement of the femur is a common clinical problem and accounts for the third highest incidence after the spine and pelvis. These patients are confronted with the possibility of losing the ability to ambulate during their remaining months. However, with improved prosthetic implants and internal fixation devices, most patients can resume their previous activities after operative treatment of their femoral fractures.

Comparative aspects of osteosarcoma. Dog versus man

Canine osteosarcoma bears striking resemblance to osteosarcoma in humans. Similarities include the following: male sex predilection, large patient size, 75% or more affecting the appendicular site, metaphyseal location, generally unknown etiology, less than 10% of patients have documented metastasis at presentation, over 90% of tumors show high-grade histology, 75% of tumors show aneuploidy, the metastatic rate is 80% or more with amputation alone, the lung is the most common site of metastasis, and there is improved survival with adjuvant chemotherapy. The major differences are age of onset, with dogs being affected in middle age; greater frequency in the dog, with over 8000 new cases per year; and time to metastasis being faster in the dog than man. Canine osteosarcoma is a readily available and highly comparable spontaneously occurring cancer that should be useful in a better understanding of the same disease in humans.

Ewing's sarcoma of bone. Experience with 140 patients

The records of 140 patients with histologically verified Ewing's sarcoma of bone treated between 1969 and 1982 were studied retrospectively. Various factors thought to be relevant to prognosis were analyzed. Three statistically significant factors were found: presence of metastatic disease, elevation of the sedimentation rate, and location of the tumor in the pelvis. In addition, patients who underwent complete surgical excision of the primary lesion had a better survival rate (74% at 5 years) than those who did not (34% at 5 years). It is concluded that patients with surgically accessible lesions should undergo treatment consisting of surgery, chemotherapy, and, in selected cases, radiation.

Ewing's sarcoma of bone. Experience with 140 patients

The records of 140 patients with histologically verified Ewing's sarcoma of bone treated between 1969 and 1982 were studied retrospectively. Various factors thought to be relevant to prognosis were analyzed. Three statistically significant factors were found: presence of metastatic disease, elevation of the sedimentation rate, and location of the tumor in the pelvis. In addition, patients who underwent complete surgical excision of the primary lesion had a better survival rate (74% at 5 years) than those who did not (34% at 5 years). It is concluded that patients with surgically accessible lesions should undergo treatment consisting of surgery, chemotherapy, and, in selected cases, radiation.

Lymph cysts or lymphocoele: a case report

A patient with a lymph cyst of the thigh following sulfuric acid burns of both feet is presented. It was diagnosed by percutaneous lymphangiography with Ethiodal. Omentopexy was performed with success. A complication of hernia of small intestine into the thigh was corrected by herniorraphy. Omentopexy is an excellent modality to improve lymph flow. Awareness of hernia post operatively may limit its use.

Limb salvage in primary malignant bone tumors

Advances in adjuvant chemotherapy and improvements in techniques of oncologic reconstruction have stimulated renewed interest in limb saving operation for malignant bone tumors. Between 1970 and 1981, 160 patients underwent local resection for malignant osseous lesions at the Mayo Clinic. This included 102 patients with chondrosarcoma, 44 with osteosarcoma, and 14 with fibrosarcoma. Ninety-three of the lesions were stage I and 67 were stage II. The overall local recurrence rate was 11.8%. The reconstructive procedures were effective in providing adequate functional restoration. Limb sparing operation is a valid viable option in carefully selected patients with malignant bone tumors. A continued search for effective adjuvant treatment programs is necessary.

Ununited fractures of the clavicle

We reviewed the cases of thirty-three patients with non-union of a clavicular fracture. The patients who seemed to have a predilection to non-union were seven who had sustained a refracture and twenty-one who had had severe trauma. Eleven patients had an atrophic non-union, and these lesions were less symptomatic than the hypertrophic non-unions in the series. Only three of the eleven patients with an atrophic non-union had an operation, compared with sixteen of the twenty-two patients with a hypertrophic non-union. The results in the nineteen patients who underwent the various surgical procedures (twenty-five operations) showed that the most successful procedure was internal fixation and bone-grafting. Even though union was achieved in twelve patients who were surgically treated, mild to moderate symptoms persisted in some.