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.