Dietary hexachlorocyclohexane induced changes in blood and liver lipids in albino mice.

Dietary intake of technical hexachlorocyclohexane (HCH) by albino mice for 2 weeks (at 400 and 800 ppm) resulted in hyperlipemia. Significant increase in triglycerides, phospholipids and cholesterol fractions of blood was observed in these animals. Dietary intake of gamma-isomer of HCH for 2 weeks (at 200 ppm) did not have any effect on blood lipid profile, but at 400 ppm level produced higher contents of phospholipids and cholesterol. The hepatomegaly produced by dietary technical HCH or gamma-HCH was not accompanied by fatty metamorphosis of liver. Hypertriglyceridemia caused by HCH was accompanied by lower triglyceride levels in liver, suggesting a possible higher rate of secretion from liver.     

Repeated dermal toxicity of technical HCH and methyl parathion (50EC) to female rats (Rattus norvigicus).

Repeated dermal application of hexachlorocyclohexane (HCH; 100 mg/kg/day) or methyl parathion (2 mg/kg/day) individually or in combination for 7, 15 and 30 days produced pathomorphological changes in skin, liver, kidney and brain of female rats along with significant enzymatic alterations in the activity of transaminase, alkaline phosphatase lactic dehydrogenase and acetylcholinesterase. The two insecticides in combination though produced severe toxicity on day 30 than at other periods, the changes were not suggestive of any additive or potentiation effect at the test doses.     

Biochemical toxicity of hexachlorocyclohexane and its gamma-isomer in albino mice

Dietary hexachlorocyclohexane (HCH) and gamma-isomer of HCH produced significant increase in liver weights of mice. Elevated levels of alanine and aspartate aminotransferases and of alkaline phosphatase in the blood of these animals suggested hepatotoxicity. Hepatic soluble enzymes--aspartate aminotransferase and lactate dehydrogenase--were markedly lowered. Among the hepatic lysosomal enzymes, acid phosphatase and acid cathepsin were increased in the experimental animals. Hepatic glucose-6-phosphatase was lowered by HCH while aldolase activity was increased. Hydrolytic enzymes in small intestine, viz., disaccharidases, lipase, amylase, dipeptidase and phosphatases, were also affected by dietary HCH and gamma-HCH. The results suggested cellular toxicity in hepatocytes of HCH and gamma-HCH fed animals, and also interference in gastrointestinal absorption.     

Have we found an ideal soft-tissue flap? An experience with 672 anterolateral thigh flaps

The free anterolateral thigh flap is becoming one of the most preferred options for soft-tissue reconstruction. Between June of 1996 and August of 2000, 672 anterolateral thigh flaps were used in 660 patients at Chang Gung Memorial Hospital. Four hundred eighty-four anterolateral thigh flaps were used for head and neck region recontruction in 475 patients, 58 flaps were used for upper extremity reconstruction in 58 patients, 121 flaps were used for lower extremity reconstruction in 119 patients, and nine flaps were used for trunk reconstruction in nine patients. Of the 672 flaps used in total, a majority (439) were musculocutaneous perforator flaps. Sixty-five were septocutaneous vessel flaps. Of these 504 flaps, 350 were fasciocutaneous and 154 were cutaneous flaps. Of the remaining 168 flaps, 95 were musculocutaneous flaps, 63 were chimeric flaps, and the remaining ten were composite musculocutaneous perforator flaps with the tensor fasciae latae. Total flap failure occurred in 12 patients (1.79 percent of the flaps) and partial failure occurred in 17 patients (2.53 percent of the flaps). Of the 12 flaps that failed completely, five were reconstructed with second anterolateral thigh flaps, four with pedicled flaps, one with a free radial forearm flap, one with skin grafting, and one with primary closure. Of the 17 flaps that failed partially, three were reconstructed with anterolateral thigh flaps, one with a free radial forearm flap, five with pedicled flaps, and eight with primary suture, skin grafting, and conservative methods.In this large series, a consistent anatomy of the main pedicle of the anterolateral thigh flap was observed. In cutaneous and fasciocutaneous flaps, the skin vessels (musculocutaneous perforators or septocutaneous vessels) were found and followed until they reached the main pedicle, regardless of the anatomic position. There were only six cases in this series in which no skin vessels were identified during the harvesting of cutaneous or fasciocutaneous anterolateral thigh flaps. In 87.1 percent of the cutaneous or fasciocutaneous flaps, the skin vessels were found to be musculocutaneous perforators; in 12.9 percent, they were found as septocutaneous vessels. The anterolateral thigh flap is a reliable flap that supplies a large area of skin. This flap can be harvested irrespective of whether the skin vessels are septocutaneous or musculocutaneous. It is a versatile soft-tissue flap in which thickness and volume can be adjusted for the extent of the defect, and it can replace most soft-tissue free flaps in most clinical situations.     

Correcting the saddlebag deformity in the massive weight loss patient

Skin redundancy of the trunk and thigh is treated by a circumferential abdominoplasty and a lower body lift. Despite preservation and tight approximation of the subcutaneous facial system, the authors have failed to adequately correct severe saddlebag deformity and midthigh laxity in the massive weight loss patient. The technique used in the last nine of the senior author's 43 lower body lifts was modified by fully abducting each operated thigh on a side utility table, before closure in the prone position. This maneuver permits an increase in width of skin excision and causes the lateral thigh skin to be taut upon leg adduction. This is a retrospective review of the senior surgeon's experience over a 3-year period. Postoperative follow-up of the nine-patient cohort ranged from 8 to 12 months. A standardized set of six-view preoperative and postoperative photographs was available for each patient. A regional grading system was developed to assign points for deformity seen in preoperative and postoperative photographs. To compare the effect of the new technique on the correction of hip/lateral thigh deformities, the authors used this same grading system to analyze 10 other lower body lift patients treated by the same surgeon without full thigh abduction who had six sets of standardized photographs. A deformity severity score was determined for each anatomic region by four trained observers blinded to the surgical technique. The nonparametric Mann-Whitney U test using exact p values was used to compare preoperative and percentage change in deformity severity score from preoperative to postoperative scores relative to preoperative scores for each anatomical region among subjects in each treatment group. The nonparametric Wilcoxon signed rank test using exact p values was used to evaluate the change in deformity severity score from preoperative to postoperative values. The change in technique resulted in an observable symmetrical correction of the severe saddlebag deformity and better contour to the distal lateral thighs. All evaluated patients were satisfied with the lateral thigh skin contour. The grading system revealed that patients treated with or without intraoperative thigh abduction had similar preoperative deformity severity scores for each anatomic region (p > 0.05). Postoperatively, all subjects showed improvement in scores for all treated regions. However, patients closed during full thigh abduction had significantly lower deformity severity scores for the hip/thigh complex when compared with patients treated without full thigh abduction (p < 0.05). Complications in these 19 patients consisted of one 6-cm superficial skin layer dehiscence due to a broken polyester suture that healed spontaneously. There were three seromas that responded to a short series of aspirations or catheter drainage. There were no infections. Distal abdominal flap tip skin necrosis in four patients responded to outpatient débridement and healed secondarily. A new grading system for body contour deformities was successfully utilized to judge differences in the quality of trunk and thigh deformity and outcome in 19 patients with adequate photographic records. Tight suture closure in full thigh abduction in the prone position results in improved treatment of significant saddlebag deformity and midthigh skin laxity in the massive weight loss patient. The essential principles are meticulous planning, careful isolation, tight closure of the lateral trunk and thigh subcutaneous fascial system, and artistic contouring of remaining tissues. Dehiscence, undesirable scarring, and seromas were minor issues in the entire group of 43 patients.     

Reduction of hexachlorocyclohexane-induced oxidative stress and cytotoxicity in rat liver by Emblica officinalis gaertn

The effect of prefeeding of dehydrated E. officinalis (amla) powder at 5 and 10% levels on hexachlorocyclohexane (HCH)-induced changes in multicomponent antioxidant system and lipid peroxides in rat liver was studied. HCH induced significant elevation in hepatic malondialdehyde, conjugated dienes and hydroperoxides. The prefeeding of amla at 10% level could decrease the formation of these lipid peroxides significantly. The HCH abuse resulted in a significant reduction in hepatic glutathione S-transferase (GST), glucose-6-phosphate dehydrogenase (G-6-PDH) and superoxide dismutase (SOD) activities with an elevation in the activities of glutathione peroxidase and gamma-glutamyl transpeptidase (GGT). On the other hand, the HCH-induced impairment in hepatic catalase, G-6-PDH and SOD activities were modulated by amla at the 10% level of intake. Prefeeding of amla at 5 and 10% levels appeared to reduce the HCH-induced raise in renal GGT activity. The results show the elevation of hepatic antioxidant system and reduction of cytotoxic products as a result of prefeeding of amla, which were otherwise affected by the HCH administration.     

Free anterolateral thigh adipofascial perforator flap

The anterolateral thigh adipofascial flap is a vascularized flap prepared from the adipofascial layer of the anterolateral thigh region. It is a perforator flap based on septocutaneous or musculocutaneous perforators of the lateral circumflex femoral system. With methods similar to those used for the free anterolateral thigh flap, only the deep fascia of the anterolateral thigh and a 2-mm-thick to 3-mm-thick layer of subcutaneous fatty tissue above the fascia were harvested. In 11 cases, this flap (length, 5 to 11 cm; width, 4 to 8 cm) was used for successful reconstruction of extremity defects. Split-thickness skin grafts were used to immediately resurface the adipofascial flaps for eight patients, and delayed skin grafting was performed for the other three patients. The advantage of the anterolateral thigh adipofascial flap is its ability to provide vascularized, thin, pliable, gliding coverage. In addition, the donor-site defect can be closed directly. Other advantages of this flap, such as safe elevation, a long wide vascular pedicle, a large flap territory, and flow-through properties that allow simultaneous reconstruction of major-vessel and soft-tissue defects, are the same as for the conventional anterolateral thigh flap. The main disadvantage of this procedure is the need for a skin graft, with the possible complications of subsequent skin graft loss or hyperpigmentation.     

The vascular supply of the extended tensor fasciae latae flap: how far can the skin paddle extend?

The vascular supply of the tensor fasciae latae flap and of the lateral thigh skin was studied in 10 cadavers to evaluate whether the lateral thigh skin toward the knee could be incorporated into an extended tensor fasciae latae flap. Within each cadaver, vascular injection of radiopaque material preceded flap elevation in one limb and followed flap elevation in the contralateral limb. Flaps raised after vascular injection were examined radiographically to evaluate the vascular anatomy of the lateral thigh skin independent of flap elevation. When vascular injection was made into the profunda femoris, the upper two-thirds of the flaps was better visualized than the distal third. When the injection was made into the popliteal artery, the vasculature of the distal third of the flaps was better visualized. Flaps raised before vascular injection were examined radiographically to delineate the anatomical territory of the vascular pedicle that had been injected. In these flaps, consistent cutaneous vascular supply was only seen in the skin overlying the tensor fasciae latae muscle, confirming that musculocutaneous perforators are the predominant means by which the pedicle of the tensor fasciae latae flap supplies the skin of the lateral thigh. Extended tensor fasciae latae flaps were elevated bilaterally in one cadaver, and selective methylene blue injections were made into the lateral circumflex femoral artery on one side and into the superior lateral genicular artery on the contralateral side. Methylene blue was observed in the proximal and distal thirds of the skin paddles, respectively, leaving unstained midzones. The vascular network of the lateral thigh skin could be divided into three zones. The lateral circumflex femoral artery and the third perforating branches of the profunda femoris artery perfuse the proximal and middle zones of the lateral thigh skin, respectively. The superior lateral genicular artery branch of the popliteal artery perfuses the distal zone. The middle and distal zones meet 8 to 10 cm above the knee joint, where the skin paddle of the tensor fasciae latae flap becomes unreliable. These data indicate that if the aim is to incorporate the skin over the distal thigh in an extended tensor fasciae latae flap without resorting to free-tissue transfer, then either a carefully planned delay procedure or an additional anastomosis to the superior lateral genicular artery is required.     

Fascial anchoring technique in medial thigh lifts

The medical thigh lift has not gained widespread acceptance since its introduction 20 years ago because of problems such as inferior scar migration, labial separation, and early recurrence of ptosis. Anchoring of the inferior skin flap to the tough, inelastic deep layer of the superficial perineal fascia has reduced such complications. Originally described by Colles in 1811, this fascial layer helps define the perineal-thigh crease. Eighteen patients having medial thigh lifts in combination with liposuction were followed for 6 to 24 months. The technique involves initial liposuction followed by resection of a crescent of redundant skin and fat at the superior medial thigh. The inferior skin flap is suspended from Colles' fascia of the perineum with subdermal PDS sutures. No undermining or deepithelialization of flaps is performed. Complications are few, and patient satisfaction is high.     

The descending branch of the superficial circumflex artery supplying anteromedial thigh skin

This report presents an extended groin flap design that consists of a conventional skin paddle in the groin region and a vertical extension in the anteromedial thigh region, based on the superficial iliac circumflex artery and an unnamed descending branch, respectively. The inferior branch of the superficial iliac circumflex artery that supplies the thigh extension of the flap, spanning approximately the upper half of the thigh region, was found to originate approximately 2 cm from the origin of the superficial iliac circumflex artery. A total of six free and four local flaps were used in 10 patients with ages ranging from 10 to 60 years (average, 45 years). There were six male and four female patients. The free flaps were required for total facial resurfacing, through-and-through cheek defect, and burn scar contractures and traumatic defects of the lower extremity. The local flaps were used for reconstruction of scrotum defect, trochanteric decubitus ulcer, and lower abdominal skin and fascia defects. All 10 flaps survived completely. The groin flap with anteromedial thigh extension offers the following advantages: (1) it is very easy and quick to elevate; (2) a significantly increased volume of tissue is available for reconstruction, based on one axial vessel and being completely reliable; (3) the flap offers two skin paddles that are independently mobile; (4) there is no need for positional change and a two-team approach is possible; and (5) it can be raised as a vertical skin island only. The authors conclude that the groin flap with anteromedial thigh extension is a useful modification for reconstruction of both distant and local defects.     

Intermediate filament typing of tumor cells in fine needle aspirates by means of monoclonal antibodies

Well-characterized monoclonal antibodies directed against different intermediate filament proteins were used in the typing of tumor cells in 30 fine needle aspiration (FNA) biopsy specimens received for routine cytologic examination to assess the value of intermediate filament typing in FNA cytology. Tumors from sites that included liver, large bowel, pancreas, breast, skin, thyroid, thigh and kidney were examined with monoclonal antibodies specific for either all keratins or keratin subsets, vimentin, desmin or specific neurofilament polypeptides. Intermediate filament typing helped to confirm, revise or refine the diagnoses made by light microscopy and provided information of value in the classification of tumors of uncertain origin.     

Multipaddled Anterolateral Thigh Chimeric Flap for Reconstruction of Complex Defects in Head and Neck

The anterolateral thigh flap has been the workhouse flap for coverage of soft-tissue defects in head and neck for decades. However, the reconstruction of multiple and complex soft-tissue defects in head and neck with multipaddled anterolateral thigh chimeric flaps is still a challenge for reconstructive surgeries. Here, a clinical series of 12 cases is reported in which multipaddled anterolateral thigh chimeric flaps were used for complex soft-tissue defects with several separately anatomic locations in head and neck. Of the 12 cases, 7 patients presented with trismus were diagnosed as advanced buccal cancer with oral submucous fibrosis, 2 tongue cancer cases were found accompanied with multiple oral mucosa lesions or buccal cancer, and 3 were hypopharyngeal cancer with anterior neck skin invaded. All soft-tissue defects were reconstructed by multipaddled anterolateral thigh chimeric flaps, including 9 tripaddled anterolateral thigh flaps and 3 bipaddled flaps. The mean length of skin paddle was 19.2 (range: 14–23) cm and the mean width was 4.9 (range: 2.5–7) cm. All flaps survived and all donor sites were closed primarily. After a mean follow-up time of 9.1 months, there were no problems with the donor or recipient sites. This study supports that the multipaddled anterolateral thigh chimeric flap is a reliable and good alternative for complex and multiple soft-tissue defects of the head and neck.     

Clinical application of the free thin anterolateral thigh flap in 31 consecutive patients

In this retrospective study, 31 reconstructions using thin anterolateral thigh flaps and six cadaveric dissections of the thigh were investigated in consideration of the anatomic variations of the perforator vessels in the adipose layer, the safe area of flap circulation, and the clinical indications.Three variations of the perforator vessel course in the adipose layer were predicted correctly. The safe radius of a thin anterolateral thigh flap with a thickness of 3 to 4 mm was determined to be approximately 9 cm from the point where the perforator met the skin. The use of a thin anterolateral thigh flap for reconstruction of the neck, axilla, anterior tibial area, dorsum of the foot, circumference on the ankle, forearm, and dorsum of the hand was therefore recommended.     

Changes in the bacterial community and lin genes diversity during biostimulation of indigenous bacterial community of hexachlorocyclohexane (HCH) dumpsite soil

In this study hexachlorocyclohexane (HCH) contaminated soil (with HCH level 84 g/kg of soil) from HCH dumpsite (Ummari village, Lucknow, India) was used to demonstrate biostimulation approach for HCH bioremediation. Different nutrients (molasses and ammonium phosphate) were used in different pits having contaminated soil to stimulate the indigenous microbial community. There was a substantial reduction in the total HCH content of the soil in 12 months long experiment. Maximum reduction was seen in the pit that received a combination of molasses and ammonium phosphate. A change in the microbial community concomitant with degradation of HCH was observed. Sphingomonads, which are known degraders of HCH, were found to dominate the experimental pits. Moreover changes in linA and linB gene (primary genes involved in HCH degradation) diversity and number were also seen as revealed by T-RFLP and RT-PCR respectively. The study suggests the prospects of biostimulation in decontaminating soils heavily contaminated with HCH.     

Comparison of gross visual and microscopic assessment of four anatomic sites to monitor Besnoitia tarandi in barren-ground caribou (Rangifer tarandus)

The objective of this study was to establish a standardized protocol to monitor Besnoitia tarandi prevalence and intensity in barren-ground caribou (Rangifer tarandus) herds by: 1) calculating the relative sensitivity and specificity of the gross visual assessment of four anatomical sites compared with microscopic evaluation, and 2) determining which of four anatomical sampling sites was the most sensitive for detecting B. tarandi cysts by microscopy. Sampled tissues consisted of the conjunctiva of the left eye and skin sections from the rostrum, metatarsus, and thigh from 312 harvested caribou. Diagnosis of infection with B. tarandi was based on observation of at least one cyst by microscopic examination. For each tissue, the maximal density of cysts (number of B. tarandi cysts/mm(2) in the section examined) was calculated for a measured area consisting of the dermis extending from the epidermis of the skin to the base of the hair follicles and adnexal structures. For the conjunctiva, the entire submucosa was evaluated. Gross visual evaluation markedly underestimated B. tarandi prevalence in caribou with a relative sensitivity ranging from 0.29 in the conjunctiva to 0.13 in the skin section from the thigh, whereas relative specificities ranged from 0.98 to 1.00. The metatarsus and rostrum skin sections had the highest probabilities of cyst detection of all four anatomical sampling sites. The metatarsus harbored significantly higher densities of B. tarandi cysts than the rostrum, thigh, or conjunctiva. In conclusion, microscopic evaluation of a skin section from the anterior aspect of the mid-third portion of the metatarsal region could be used as a standardized comparative indicator of density of B. tarandi infection in Rangifer.     

The adductor flap: a new method for transferring posterior and medial thigh skin

Skin flaps from the medial aspect of the thigh have traditionally been based on the gracilis musculocutaneous unit. This article presents anatomic studies and clinical experience with a new flap from the medial and posterior aspects of the thigh based on the proximal musculocutaneous perforator of the adductor magnus muscle and its venae comitantes. This cutaneous artery represents the termination of the first medial branch of the profunda femoris artery and is consistently large enough in caliber to support much larger skin flaps than the gracilis musculocutaneous flap. In all 20 cadaver dissections, the proximal cutaneous perforator of the adductor magnus muscle was present and measured between 0.8 and 1.1 mm in diameter, making it one of the largest skin perforators in the entire body. Based on this anatomic observation, skin flaps as large as 30 x 23 cm from the medial and posterior aspects of the thigh were successfully transferred. Adductor flaps were used in 25 patients. On one patient the flap was lost, in one the flap demonstrated partial survival, and in 23 patients the flaps survived completely. The flap was designed as a pedicle island flap in 14 patients and as a free flap in 11.When isolating the vascular pedicle for free tissue transfer, the cutaneous artery is dissected from the surrounding adductor magnus muscle and no muscle is included in the flap. Using this maneuver, a pedicle length of approximately 8 cm is isolated. In addition to ample length, the artery has a diameter of approximately 2 mm at its origin from the profunda femoris artery. The adductor flap provides an alternative method for flap design in the posteromedial thigh. Because of the large pedicle and the vast cutaneous territory that it reliably supplies, the authors believe that the adductor flap is the most versatile and dependable method for transferring flaps from the posteromedial thigh region.     

Hyphantria cunea ferritin heavy chain homologue: cDNA sequence and mRNA expression

We have sequenced a cDNA clone encoding a 26-kDa ferritin subunit, which was heavy chain homologue (HCH), in fall webworm, Hyphantria cunea. The HCH cDNA was obtained from the screening of a cDNA library using a PCR product. H. cunea ferritin is composed of 221 amino acid residues and their calculated mass is 26,160 Da. The protein contains the conserved motifs for the ferroxidase center typical for heavy chains of vertebrate ferritin. The iron-responsive element sequence with a predicted stem-loop structure is present in the 5'-untranslated region of ferritin HCH mRNA. The sequence alignment of ferritin HCH shows 68.9 and 68.7% identity with Galleria mellonella HCH (26 kDa ferritin) and Manduca sexta HCH, respectively. While G type insect ferritin vertebrate light chain homologue (LCH) is distantly related to H. cunea ferritin HCH (17.2-20.8%), the Northern blot analysis revealed that H. cunea ferritin HCH was ubiquitously expressed in various tissues and all developmental stages. The ferritin expression of midgut is more responsive to iron-fed, compared to fat body in H. cunea.     

The thigh flap: an osteomyocutaneous free-flap model in the rat

A new experimental model for free-flap transfer has been developed in the rat. This "thigh flap" is an osteomyocutaneous free flap of bone (femur), muscle (thigh), and skin (groin) based on the femoral vessels. The flap is harvested from the left groin and thigh of an inbred female rat and is transferred to a subcutaneous pocket in the left groin of a male rat of the same inbred strain. The femoral vessels supplying the flap are anastomosed end-to-end with the femoral vessels of the recipient. Thirty flaps have been transferred, with 5 technical failures. Three of the remaining 25 flaps developed necrosis within 24 hours. The other 22 flaps remained viable until the rat was sacrificed at 7 days. The survival rate of the thigh flap was thus 88 percent. The model is suitable for use in metabolic, vascular, and immunologic studies of composite free flaps.     

Anterolateral thigh flap donor-site complications and morbidity

The authors examined donor-site complications and morbidity in 37 patients after reconstruction with free or pedicled anterolateral thigh flaps. Intraoperative assessment included damage to the vastus lateralis muscle and whether the main pedicle of the rectus femoris muscle had been killed. Postoperative assessment of the donor site included wound healing, range of motion, muscle strength, gait, and sensation. Patients were surveyed with a questionnaire about fatigue in their activities of daily life and the appearance of the donor site. All 32 patients who underwent primary skin closure could perform activities of daily life normally, and most (87.5 percent) reported that donor-site appearance was satisfactory. However, the severity of donor-site dysfunction was related to the degree of damage to the vastus lateralis muscle, and most patients (87.5 percent) had some loss of sensation at the anterolateral aspect of the thigh. Because of adhesions between the meshed skin graft and the underlying fascia, range of motion at the hip and knee was limited in significantly more patients who had received split-thickness skin grafts (60 percent) than patients who had undergone primary skin closure (3.1 percent). Therefore, wider flaps or flaps harvested nearer the knee may increase donor-site morbidity. The authors concluded that the incidence of long-term morbidity with the anterolateral thigh flap is low, although it is increased when the flap includes the vastus lateralis muscle or is wider and requires additional skin grafting at the donor site.     

Acute Hexachlorocyclohexane-Induced Oxidative Stress in Rat Cerebral Hemisphere

Hexachlorocyclohexane (HCH) is reported to induce oxidative stress in liver and testis of rat. With an objective to examine its effect on brain tissue acute toxicity of HCH (10 and 20 mg/kg body wt, i.p.) on the antioxidant defense system of cerebral hemisphere of rat was evaluated. Lipid peroxidation (LPX) was elevated after 24 h in the crude homogenate and sub-cellular fractions (nuclear and mitochondrial) except the microsomal fraction in which LPX was induced after 6 h and remained elevated till 24 h. The pesticide elicited decrease in the activities of cytosolic total, CN^–-sensitive (not at 24 h) and CN-resistant superoxide dismutases; total, Se-dependent and Se-independent glutathione peroxidases; and catalase throughout the measurement period. In contrast, glutathione reductase activity was elevated till 24 h after a fall at 6 h of pesticide exposure. Cerebral contents of glutathione and ascorbic acid were decreased in response to HCH. The results suggest the possible involvement of reactive oxygen species in the mechanism of HCH-induced neurotoxicity in rat.