Changes in social mixing and attitudes and practices to precautionary measures in a maturing COVID-19 pandemic in six communities in Sudan: a qualitative study

INTRODUCTION

With low COVID-19 vaccination coverage, non-pharmaceutical interventions were critical to mitigating the COVID-19 pandemic in Sudan. We explored changes in social contact patterns, risk perception, attitudes, and practices toward protective measures during an evolving COVID-19 outbreak in six illustrative communities in Sudan.

METHODS

This qualitative study took place in six communities in five Sudanese states using focus group discussions with community members and non-participant structured observations in public spaces between March 2021 and April 2021. A total of 117 participants joined 24 group discussions. We used a two-stage thematic analysis.

RESULTS

The perceived importance of compliance with individual preventative measures among those who believe in COVID-19 was higher than observed compliance with behaviors in most study sites. Adherence was consistently low and mainly driven by enforced movement restrictions. As restrictions were lifted, social contacts outside the household resumed pre-COVID-19 levels, and risk perception and individual and institutional adherence to protective measures diminished. We identified an environment that is socially and economically unsupportive of preventive practices, compounded by widespread rumours, misinformation, and mistrust in the government-led response. However, we identified new social habits that can contribute to reducing COVID-19 transmission.

CONCLUSION

The unfavourable social and economic environment, coupled with the low visibility of the pandemic and pandemic response, has likely modulated the influence of higher risk perception on adopting precautionary behaviours by individuals. Governments and non-governmental actors should increase the visibility of the pandemic and pandemic response, enforce and incentivise infection control measures in public areas, promote emerging preventive social habits, and actively track and address rumours and misinformation related to COVID-19 and COVID-19 vaccines.

Population mortality before and during the COVID-19 epidemic in two Sudanese settings: a key informant study

BACKGROUND

Population mortality is an important metric that sums information from different public health risk factors into a single indicator of health. However, the impact of COVID-19 on population mortality in low-income and crisis-affected countries like Sudan remains difficult to measure. Using a community-led approach, we estimated excess mortality during the COVID-19 epidemic in two Sudanese communities.

METHODS

Three sets of key informants in two study locations, identified by community-based research teams, were administered a standardised questionnaire to list all known decedents from January 2017 to February 2021. Based on key variables, we linked the records before analysing the data using a capture-recapture statistical technique that models the overlap among lists to estimate the true number of deaths.

RESULTS

We estimated that deaths per day were 5.5 times higher between March 2020 and February 2021 compared to the pre-pandemic period in East Gezira, while in El Obeid City, the rate was 1.6 times higher.

CONCLUSION

This study suggests that using a community-led capture-recapture methodology to measure excess mortality is a feasible approach in Sudan and similar settings. Deploying similar community-led estimation methodologies should be considered wherever crises and weak health infrastructure prevent an accurate and timely real-time understanding of epidemics' mortality impact in real-time.

[Long Noncoding RNAs MEG3, TUG1, and hsa-miR-21-3p Are Potential Diagnostic Biomarkers for Coronary Artery Disease]

Peripheral blood biomarkers are of particular importance to diagnose certain diseases including coronary artery disease (CAD) due to their non-invasiveness. Investigating the expression of noncoding RNAs (ncRNAs) paves the way to early disease diagnosis, prognosis, and treatment. Consequently, in this research, we aimed to investigate a panel of ncRNAs as potential biomarkers in patients with coronary artery disease. Two different groups have been designed (control and CAD). All participants were subjected to interviews and clinical examinations. Peripheral blood samples were collected, and plasma was extracted. At the same time, target ncRNAs have been selected based on literature review and bioinformatic analysis, and later they underwent investigation using quantitative real-time PCR. The selected panel encompassed the long non-coding RNAs (lncRNAs) MEG3, TUG1, and SRA1, and one related microRNA (miRNA): hsa-miR-21-3p. We observed statistically significant upregulation in MEG3, TUG1, and hsa-miR21-3p in CAD patients compared to control participants (p-value < 0.01). Nevertheless, SRA1 exhibited downregulation with no statistical significance (p-value > 0.05). All ncRNAs under study displayed a significantly strong correlation with disease incidence, age, and smoking. Network construction revealed a strong relationship between MEG3 and TUG1. ROC analysis indicated high potentiality for hsa-miR-21-3p to be a promising biomarker for CAD. Moreover, MEG3 and TUG1 displayed distinguished diagnostic discrimination but less than hsa-miR-21-3p, all of them exhibited strong statistical significance differences between CAD and control groups. Conclusively, this research pinpointed that MEG3, TUG1, and hsa-miR-21-3p are potential biomarkers of CAD incidence and diagnosis.

Immunomodulatory and anti-cancer potential of cloves (Syzygium aromaticum) bud extract and its phytogenic silver nanoparticles

Clove plant (Syzygium aromaticum) is one of the Myrtaceae family. It's a common flavor in food and the traditional medicine. The study's objective was to ascertain whether the clove bud aqueous extract (CAE) and CAE + nanosilver have any biological effects on immune cells and HT-29 colon cancer cell line. Nanosilver was produced through green synthesis approach using CAE. Produced nanosilver was characterized via electron microscope (scanning, SEM) and ultraviolet-visible spectroscopy. CAE and CAE + nanosilver were examined for their active biomolecules using FTIR analysis, p53 contents using real-time PCR, apoptosis and cell cycle arrest power on HT-29 cancer cell line via flow cytometerty and immunomodulatory potential utilizing MTT assay. Results cleared that a spherical nanosilver with a diameter range of 53 nm was formed by CAE. There were several active biomolecules in CAE and CAE + nanosilver. CAE and CAE + nanosilver increased the p53 protein expression and apoptotic cell number in HT-29 colon cancer cells. CAE and CAE + nanosilver could arrest HT-29 cells at the phase G2/M. CAE and CAE + nanosilver stimulated quiescent and PHA-pre-treated splenic cells at higher concentrations, and CAE suppressed quiescent splenic cell when diluted. In conclusion, the safe edible Syzygium aromaticum plant can be utilized to make anti-tumor agent, essentially for colon tumor. As Syzygium aromaticum plant could stimulate immune cells, it can be used as immune-stimulatory agent that can help fight tumor and tumor development.

Biodiversity, distributions and isolation of microplastics pollution in finfish species in the Panjkora River at Lower and Upper Dir districts of Khyber Pakhtunkhwa province of Pakistan

The basic aim of this study was aimed to determine the ichthyofaunal diversity of River Panjkora in both upper and lower Dir districts in Khyber Pakhtunkhwa province of Pakistan.Fish samples were collected by using fishnets from March to September 2020. A total of 724 specimens were collected and classified into 5 families, 14 genera, and 18 species. The overall results revealed that most fish fauna of river Panjkora contains 8 species of family Cyprinidae (56.49%) followed by 4 species of Nemacheilidae (24.44%), 2 species of Channidae (10.63%), and Sisoridae (7.04%), and 1 species of Mastacembelidae (1.38%), respectively. Among all kinds of fish species, Schizothorax plagiostomus (16.57%) was highly dominated and followed by Carassius auratus (11.87%) and Racoma labiata (9.66%) and were reported as highly abundant, especially during April, May, and June. The least abundant species were Glyptothorax punjabensis, Glyptothorax sufii, and Mastacembelus armatus, that constituting 2.48%, 2.20%, and 1.38% of the total fish samples. The Overall Simpson's diversity (1-D= 0.919) and Simpson's Reciprocal index values (1/D= 12.3876), and Shannon's index (H= 2.68) were indicating that river Panjkora contains a quite rich and diverse group of fish species. The highest microplastics observed in site 7 compared to other study area. Conservation steps should be taken as a top priority to protect and conserve the marine environment and natural heritage from further loss, extinction and stop or minimize losses incurred through irresponsible fishery practices.

Growth performance and survivability of the Asian seabass Lates calcarifer (Bloch, 1790) reared under hyper-saline, hypo-saline and freshwater environments in a closed aquaculture system

Salinity is one of the most critical environmental parameters regarding fish physiology, modifying food intake and growth performance in many fish species. The present study has investigated the effects of different salinity levels on growth performance, feeding and survival of Asian seabass Lates calcarifer juveniles. Asian seabass juveniles were reared at 0 (T1), 5 (T2), 22 (T3), 36 (T4), and 42 (T5) ppt salinity. Approximately eight hundred thirty fish individuals with an average weight of 1.24±0.52 g were randomly distributed (166 fish/Tank) in 5 concrete tanks (each tank 30×6×4 ft, volume 19,122 L) for forty days. Juveniles were initially fed 42% crude protein-containing diets at a rate of 6% of their body weight per day. The results showed that salinity level had a significant effect on the weight gain (WG), average daily weight gain (ADWG), specific growth rate (SGR), feed conversion ratio (FCR), survival rate (SR), total biomass and health indices (p<0.05). The highest WG (39.11±1.49 g), ADWG (1.00±0.12 g), SGR (8.74±0.03% d-1) and lowest FCR (0.96±0.20) were observed with T3 treatment, which was significantly higher compared to other treatment groups (p<0.05). Among the health indices, the highest hepatosomatic index and viscerosomatic index were found with T3 treatment, significantly higher than the other groups (p<0.05). No significant differences were found among the treatments in terms of survival rate (p>0.05), but the maximum survival rate (98.89±0.0%) was observed in the T3 and T2 treatments. The maximum level of crude proteins (19.99±1.4%) was found in the whole-body biochemical composition of Asian seabass juveniles in the T3 treatment group. The second-order polynomial regression showed that 20 ppt salinity is optimum for the best growth of Asian seabass. Thus, the present study recommends 20 to 36 ppt salinity for the commercial farming of Asian seabass under a closed aquaculture system.

267 An Audit of The Management of Acute Cholecystitis At ELHT

Aim

Acute cholecystitis is a common condition on the surgical take. The evidence shows that the optimal approach is with early laparoscopic cholecystectomy in patients suitable for surgery (Cao, 2015). The aim of this audit was to assess the adherence of the surgical department at ELHT to NICE guidance CG 188 in the management of patients with gallstone disease (NICE, 2014): Offer early laparoscopic cholecystectomy (within 1 week of diagnosis) for acute cholecystitis.

Method

Retrospective study of all patients with image confirmed diagnosis of acute cholecystitis between 25th January to 1st October 2018. Any unsuitable candidates for surgery were not counted.

Results

The case notes of 153 patients were reviewed. 109 were included in this study, as the other patients were not likely to be offered surgery due to their comorbidities. Of these 109 patients, 51 (47%) had a laparoscopic cholecystectomy within a week of diagnosis.

Conclusions

ELHT is not meeting the target of management within 7 days for over half of patients. The modifiable reasons for not meeting the targeted treatment time are a lack of capacity in theatre and Consultants’ decisions to delay treatment. The addition of a dedicated hot gallbladder theatre list can increase the numbers treated within the target time.

Acrylonitrile-induced reversible inhibition of uridine uptake by isolated rat intestinal epithelial cells

Isolated rat intestinal epithelial cells (IEC) were used to investigate the mechanism(s) of acrylonitrile (VCN)-induced gastro-intestinal damage. The isolated cells were 93% structurally intact for 60 min, as indicated by trypan blue exclusion. Uridine uptake by isolated IEC was linear from 6-20 min, after which a steady state was reached for up to 40 min. Exposure of isolated IEC to various concentrations of VCN reduced the ability of the cells to take up uridine in a concentration-dependent manner. A concentration of 82 mum VCN inhibited the [(3)H]uridine uptake of the cells by 50% (IU(50)). A time-course study indicated that the maximal inhibition of uridine uptake occurred at 15 min after exposure to VCN. The VCN-induced inhibition of uridine uptake was found to be reversible. IEC exposed to two sublethal doses of VCN (41 and 82 mum) for 15 min regained normal uridine uptake activity within 50 min after removal of VCN. The present study provides a sensitive approach for the detection and evaluation of cytotoxic risk of sublethal doses of the gastro-intestinal toxin VCN using IEC as target cells. The observed in vitro cytotoxicity of sublethal doses of VCN will be used to investigate further the mechanism of VCN-induced gastro-intestinal damage.

Chloroacetonitrile induces intrauterine growth restriction and musculoskeletal toxicity in fetal mouse

Chloroacetonitrile (CAN) is a by-product of chlorination of drinking water. Epidemiological studies indicate that it might present a hazard to human health. The present study was designed to investigate the potential adverse effects of intrauterine exposure to CAN on fetal body weight and development of the musculoskeletal system in mice. At gestation day 6, pregnant mice were given CAN (12.5, 25, or 50 mg/kg/day) till gestation day 18. Uteri were then examined and live fetuses were collected, weighed, and evaluated for any malformations. High doses of CAN (50 mg/kg) significantly elevated fetal anomalies and reduced fetal viability. Chloroacetonitrile at a dose of 25 mg/kg did not affect fetal viability and significantly reduced fetal body weight. Subsequent experimentation was performed using this dose level. Histological examination of fetal axial skeleton indicated that CAN resulted in delayed appearance of endochondral ossification centers, widening of the vertebrae, and destruction of the calcified zone. In addition, the skeletal muscle fibers were markedly distorted, were small in size, and were widely separated by connective tissue. Both connective tissue perimysium and endomysium were less cellular compared with control sections. The histological findings were further confirmed by assessing the morphometric changes. Ratios of calcified cartilage to non-calcified cartilage areas in both control and CAN-exposed groups were determined. Also, skeletal muscle fiber diameter of CAN-exposed fetuses was significantly decreased compared with control group. In conclusion, intrauterine exposure to low levels of CAN decreases fetal body weight and induces malformations in the musculoskeletal system in mice.

Comparative disposition of the antineoplastic agent 9-nitrocampotothecin and the inactive isomer 12-nitro camptothecin in CASE-bearing nude mice: effect of route of administration on tissue distribution

PURPOSE

9-Nitrocamptothecin (9-NC) and 12-nitrocamptothecin (12-NC) are synthetic structural analogues of camptothecin (CPT) which have been prepared to explore the structure/activity relationship of this group of compounds against a wide variety of experimental tumors. As part of our investigation of the pharmacology and the mechanism of tumor inhibition of these compounds, we examined the effect of route of administration on the distribution of tritium-labeled 9-NC and 12-NC, an active and a poor chemotherapeutic agent, respectively.

METHODS

Quantitative whole-body autoradiography was used and our results were compared with previous results obtained with the parent compound CPT.

RESULTS

These studies revealed that, independent of the route of administration, both CPT derivatives were rapidly distributed to gall bladder, gastrointestinal tract and kidney. The excretion from these organs was indicated by the high levels of radioactivity in urine (urinary bladder) and feces (large intestines). The studies also indicated that the distributions of 9-NC and 12-NC were qualitatively similar, but quantitatively higher uptake of radioactivity was observed in animals treated with 12-NC than in those treated with 9-NC at 30 min following treatment. With the exception of the late sampling time (12 h after administration), the accumulation of radioactivity in the lungs (bronchioles) of animals that received an intravenous (i.v.) dose of 9-NC or 12-NC was higher than those treated with an intramuscular (i.m.) dose. However, the retention of drug-derived radioactivity in the tumors of mice treated with an i.m. dose of 9-NC was higher than that in the tumors of i.v.-treated animals and was also higher than that in tumors of animals treated with 12-NC.

CONCLUSIONS

These results suggest that higher accumulation of 9-NC in tumor tissues than of 12-NC may contribute to the more potent chemotherapeutic activity of the former agent. Our results also suggest that i.m. injection is a more effective route of administration than i.v. administration.

Pharmacology of camptothecin esters

An intact lactone ring of camptothecins is a structural requirement for their anticancer activity. Propionate esters of camptothecin (CPT) and 9-nitrocamptothecin (9NC), CZ48 and CZ112, respectively, have been synthesized as derivatives resistant to lactone hydrolysis and are chemotherapeutically active. In this study, we have examined the mechanism of action of CZ48 and CZ112 and their distribution, metabolism, and toxicity. CZ112 incubated in human plasma retained its lactone structure longer than 9NC (t1/2: 10.5 and < 1 hr for CZ112 and 9NC, respectively). This resistance to lactone hydrolysis was also observed in mouse plasma or albumin solutions. Neither CZ48 nor CZ112 inhibit topoisomerase I and thus are prodrugs dependent on hydrolysis to CPT or 9NC, respectively. Rates of hydrolysis of CZ48 to CPT are higher by homogenates of mouse liver, spleen, lung, and kidney than by plasma. Rates of hydrolysis by tumor cells in culture vary and were higher by breast cancer and melanoma cells than by colon cancer cells. On the basis of these and other data, it is proposed that CZ48 and CZ112 may act as anticancer agents by resisting hydrolysis to camptothecins while in circulation. Hydrolysis in tissues may release intact lactone in target tissues.

Chloroacetonitrile (CAN) induces glutathione depletion and 8-hydroxylation of guanine bases in rat gastric mucosa

Chloroacetonitrile (CAN) is detected in drinking-water supplies as a by-product of the chlorination process. Gastroesophageal tissues are potential target sites of acute and chronic toxicity by haloacetonitriles (HAN). To examine the mechanism of CAN toxicity, we studied its effect on glutathione (GSH) homeostasis and its impact on oxidative DNA damage in gastric mucosal cells of rats. Following a single oral dose (38 or 76 mg/Kg) of CAN, animals were sacrificed at various times (0-24 h), and mucosa from pyloric stomach were collected. The effects of CAN treatment on gastric GSH contents and the integrity of genomic gastric DNA were assessed. Oxidative damage to gastric DNA was evaluated by measuring the levels of 8-Hydroxydeoxyguanosine (8-OHdG) in hydrolyzed DNA by HPLC-EC. The results indicate that CAN induced a significant, dose- and time-dependent, decrease in GSH levels in pyloric stomach mucosa at 2 and 4 hours after treatment (56 and 39% of control, respectively). DNA damage was observed electrophoretically at 6 and 12 hours following CAN administration. CAN (38 mg/Kg) induced significant elevation in levels of 8-OHdG in gastric DNA. Maximum levels of 8-OHdG in gastric DNA were observed at 6 hours after CAN treatment [9.59+/-0.60 (8-OHdG/10(5)dG) 146% of control]. When a high dose of CAN (76 mg/Kg) was used, a peak level of 8-OHdG [11.59+/-1.30 (8-OHdG/10(5)dG) 177% of control] was observed at earlier times (2 h) following treatment. When CAN was incubated with gastric mucosal cells, a concentration-dependent cyanide liberation and significant decrease in cellular ATP levels were detected. These data indicate that a mechanism for CAN-induced toxicity may be partially mediated by depletion of glutathione, release of cyanide, interruption of the energy metabolism, and induction of oxidative stress that leads to oxidative damage to gastric DNA.

Induction of oxidative stress and TNF-alpha secretion by dichloroacetonitrile, a water disinfectant by-product, as possible mediators of apoptosis or necrosis in a murine macrophage cell line (RAW)

The water disinfectant by-product dichloroacetonitrile (DCAN) is a direct-acting mutagen and induces DNA strand breaks in cultured human lymphoblastic cells. Cellular activation by environmental agents may exert detrimental effects to the cells. Activated macrophages produce reactive oxygen intermediates such as H(2)O(2), (-)OH and O(2). Therefore, the effect of various concentrations of DCAN (100-400 microM) on the activity macrophage cells (RAW 264.7) was studied. In these cells, DCAN-induced oxidative stress was characterized by the production of reactive oxygen intermediates (ROI). Also, the ratios of intracellular GSH/GSSG was assessed and used as a biomarker for oxidative stress. The secretion of TNF-alpha was assessed since macrophages are known to secrete TNF-alpha as a result of cellular oxidative stress. Electrophoretic detection of DNA degradation and light microscopy was utilized for the characterization of DCAN-induced apoptosis. Lactate dehydrogenase (LDH) leakage and trypan blue exclusion were used as markers of cellular necrosis. Following exposure to DCAN (200 microM and 400 microM), intracellular GSSG was increased (2.5-fold of control, P<0. 05). DCAN activation of RAW cells was detected by elevated levels of intracellular ROI (1.9-2.5-fold than control, P<0.05) and increased secretion of TNF-alpha (4.5 fold-than control, P <0.05). Elecrophoresis of genomic DNA of treated cells indicated a dose-dependent increase in degradation of genomic DNA. Morphological studies also indicated that exposure of RAW cells to 100 microM or 200 microM DCAN incites apoptotic cell death. At higher concentrations (400 microM), however, significant (P<0.05) increase in LDH leakage and decrease in cell viability (55% of control) indicative of cellular necrosis, were observed. These studies indicate that DCAN induces dose-dependent apoptosis or necrosis in RAW cells that could be due to the disturbance in intracellular redox status and initiation of ROI-mediated oxidative mechanisms of cellular damage.

Modulation of base excision repair by low density lipoprotein, oxidized low density lipoprotein and antioxidants in mouse monocytes

In the present study, we found that oxidized low density lipoprotein, but not low density lipoprotein, down-regulated base excision repair activity in extracts of mouse monocyte cell line PU5-1.8. An enzyme required in this pathway, DNA polymerase beta, was also down-regulated. In contrast, treatment of monocytes with a combination of ascorbate and alpha-tocopherol up-regulated base excision repair activity and expression of DNA polymerase beta. Co-treatment of monocytes with antioxidants plus oxidized low density lipoprotein prevented down-regulation by oxidized low density lipoprotein. Oxidative DNA damage, as measured by 8-hydroxyguanine accumulation in genomic DNA, was found in cells treated with oxidized low density lipoprotein; 8-hydroxyguanine was not found in the cells treated with low density lipoprotein, antioxidants or oxidized low density lipoprotein plus antioxidants. These results establish a linkage between the DNA base excision repair pathway, oxidative DNA damage and oxidized low density lipoprotein treatment in mouse monocytes. Since oxidized low density lipoprotein is implicated in chronic disease conditions such as atherogenesis, these findings facilitate understanding of genetic toxicology mechanisms related to human health and disease.

Serum autoantibodies in patients with primary sclerosing cholangitis

BACKGROUND/AIM

Primary sclerosing cholangitis is a chronic cholestatic syndrome with a presumed autoimmune basis frequently associated with inflammatory bowel disease. The aim of this study was to determine the profile and significance of serum autoantibodies in patients with primary sclerosing cholangitis.

METHODS

Serum samples taken from 73 untreated patients (32 female and 41 male, median age 45 years) with well-defined primary sclerosing cholangitis, and from 75 healthy age- and sex-matched controls were assayed for 20 different autoantibodies.

RESULTS

Of 73 patients, 71 (97%) were positive for at least 1 autoantibody; whereas 59/73 patients (81%) were positive for > or =3 antibodies. Patients with primary sclerosing cholangitis had a significantly greater rate of positivity than controls for antinuclear, anticardiolipin, antineutrophil cytoplasmic, and antithyroperoxidase antibodies as well as rheumatoid factor. The rate of positivity and serum levels of any of these 20 autoantibodies were not significantly different between patients with primary sclerosing cholangitis and inflammatory bowel disease and those without inflammatory bowel disease. Anticardiolipins were the single group of antibodies that had a significant correlation with the Mayo risk score (r=0.49, p<0.001) and histologic stage of disease (r=0.30, p<0.01).

CONCLUSIONS

Primary sclerosing cholangitis is associated with a high proportion of non-organ specific autoantibodies. Anticardiolipin antibodies appear to be related to the severity of primary sclerosing cholangitis and may be a useful prognostic marker.

An IgG antiprothrombin antibody enhances prothrombin binding to damaged endothelial cells and shortens plasma coagulation times

OBJECTIVE

To test the hypothesis that some lupus anticoagulants are antiprothrombin antibodies, and that such antibodies enhance prothrombin binding to endothelial cells (EC) and thus promote clotting on the cell surface.

METHODS

We generated a monoclonal antiprothrombin antibody (designated IS6) from a patient with primary antiphospholipid syndrome (APS). The antibody was analyzed for its binding properties, lupus anticoagulant activity, and pathophysiologic activity, using an EC-based plasma coagulation assay.

RESULTS

IS6 is the first patient-derived monoclonal IgG antiprothrombin antibody. It bound to prothrombin with low affinity, reacted with 3 phospholipids (cardiolipin, phosphatidylethanolamine, and phosphatidylserine), and showed lupus anticoagulant activity. Moreover, IS6 enhanced the binding of prothrombin to damaged EC and shortened the EC-based plasma coagulation times.

CONCLUSION

These findings suggest that IS6 may promote coagulation in areas of damaged EC in the host, and thus contribute to thrombosis in patients with APS.

Surrogate markers of disease activity in patients with Takayasu arteritis. A preliminary report from The International Network for the Study of the Systemic Vasculitides (INSSYS)

Twenty-nine patients with clinically defined Takayasu arteritis and 26 healthy control volunteers were recruited by INSSYS investigators from their clinical practices. Patients with Takayasu arteritis were divided into those with clear-cut clinically active or inactive disease based on Birmingham Vasculitis Activity Scores. Multiple serological tests were performed including ESR, C-reactive protein, tissue factor, von Willebrand factor, thrombomodulin, tissue plasminogen activator, ICAM-1, VCAM-1, E-selectin and PECAM-1. No test was reliably able to distinguish between healthy volunteers and patients with active Takayasu arteritis. At present there is no known serological test which can consistently supplant vascular histopathology in determining the activity of Takayasu arteritis.

Pharmacodynamics of recombinant human DNase I in serum

Recombinant human deoxyribonuclease I (rhDNase) may be an effective therapeutic for the treatment of systemic lupus erythematosus (SLE). The pharmacodynamics of rhDNase in serum was investigated using two activity assays: one based on hydrolysis of a radiolabelled phage DNA and the other based on hydrolysis of human chromatin. The concentration of endogenous immunoreactive DNase in sera from 16 normal subjects was 3.2 +/- 1.4 ng/ml (mean +/- s.d.); however, low levels or no nuclease activity were detected in the same sera, suggesting the presence of DNase inhibitors. We assessed the ability of rhDNase to degrade DNA in undiluted serum, since the observed inhibition of endogenous DNase was reversed upon dilution. Addition of rhDNase to undiluted serum at a concentration of 50-100 ng/ml was necessary for degradation of radiolabelled phage DNA. The activity of rhDNase added to serum from normal subjects and SLE patients was similar. rhDNase degraded human chromatin and chromatin/anti-DNA immune complexes in serum with similar potency (EC50 approximately 100-200 ng/ml). A 500-fold variation in the chromatin/anti-DNA stoichiometry did not significantly affect the digestion of these immune complexes by rhDNase in buffer. These results indicate that a minimum rhDNase concentration of 50-100 ng/ml in serum was required to achieve detectable catalytic activity and that the presence of antibodies to DNA did not inhibit the degradation of DNA/anti-DNA immune complexes.

Effect of glutathione modulation of the distribution and transplacental uptake of 2-[14C]-chloroacetonitrile (CAN) quantitative whole-body autoradiographic study in pregnant mice

Chloroacetonitrile (CAN), a drinking water disinfectant by-product, has mutagenic and carcinogenic properties. CAN is known to deplete glutathione (GSH), and previous studies reported an enhanced molecular interaction of CAN after GSH depletion in the uterine and fetal tissues of mice. The present report may help to understand the potential mechanisms involved in such molecular interactions by examining the disposition, transplacental uptake and covalent interaction of the chemical in normal and GSH depleted pregnant mice (at 13th day of gestation). Both normal and GSH depleted (by administration of Diethylmaleate (DEM), 0.6 mL/kg, i.p.) pregnant mice were given an equitoxic i.v. dose of 2-[14C]-CAN(333 microCi/kg equivalent to 77 mg/kg). Animals were processed for whole-body autoradiography (WBA) at 1, 8 and 24 hr after treatment. Tissue distribution of radioactivity in the autoradiographs was quantitated using computer aided image analysis. With few exceptions, a rapid high uptake (at 1 hr) of radioactivity was observed in all major maternal (liver, lung, urinary bladder, gastrointestinal mucosa, cerebellum, uterine luminal fluid) and fetal (liver, brain) organs of both normal and GSH depleted mice. This pattern of distribution was observed, with lesser intensity, at 8 hr following treatment. At a later time period (24 hr), there was a significant higher retention and covalent interaction of radioactivity in GSH depleted mouse tissues especially in the liver as compared to normal mouse. This study suggests that 2-[14C]-CAN and/or its metabolites are capable of crossing the placental barrier. The observed higher uptake and retention of the radioactivity in the maternal liver, kidney, cerebellum, nasal turbinates and fetal liver may pose toxicity of the chemical to these organs. The increased covalent interaction of radioactivty in GSH depleted mice liver may indicate the potential utilization of GSH pathway by this organ in the detoxication of CAN derived metabolites and thus exerting hepatotoxicity.

Clinical presentation and CAT scan findings in mycetoma of the head

Nine cases comprising seven males and two females with mycetoma of the cranium were studied between January 1990 and June 1997. Streptomyces somaliensis was the most common causative organism. The source of the infection was thought to be known in only three cases. The common mode of presentation was headache and scalp swelling. The next common presentation was epilepsy. Other focal neurological disorders also occur. CT scan findings of the cranium showed osteosclerotic rather than osteolytic changes.

Possible functional immunotoxicity of acrylonitrile (VCN)

Acrylonitrile (vinyl cyanide, VCN), an environmental pollutant, has been shown to be an animal and human carcinogen particularly for the GIT. In a previous work done in our laboratory, VCN induced immunosuppressive effects as indicated by a decrease in plaque forming cell (PFC) response to SRBCs (sheep red blood cell) immunization, a marked depletion of spleen lymphocyte subsets by flow cytometric analysis as well as bacterial translocation of the normal flora leading to brachial lymph node abscess. This work was carried out to evaluate the systemic and/or local immunotoxic potential of VCN. Acrylonitrile (2.7 mg kg-1 day-1) was given to CD-1 mice once daily for 5, 10 and 15 days. Immunohistochemical assessment of the number of cells capable of producing IgA in different intestinal compartments (duodenum, jejunum and ileum) revealed a significant decrease following VCN treatment. On the contrary, Bromodeoxyuridine (BrdU) incorporation in gut epithelial cells (duodenum and ileum) showed a significant increase in the same VCN-treated groups of animals. On the other hand, [3H]thymidine uptake was significantly decreased in splenocytes stimulated with phytohemaglutinin (PHA), Concanavalin-A (Con-A) and Lipopolysaccharide (LPS) and derived from animals treated with VCN. The effects of VCN were started after 5 days and increased up to 15 days of daily treatment in most of the investigated parameters. The results suggested that VCN has a profound immunosuppressive effect either systemically or locally which could be a contributing factor in its GIT carcinogenicity.

Determination of the distribution of malathion in rats following various routes of administration by whole-body electronic autoradiography

The distribution of [14C]-malathion, an organophosphorus pesticide, in rats after intravenous, oral and dermal administration was carried out using electronic autoradiography of whole body sections of treated animals. The study indicated that a major difference in the disposition of [14C]-malathion occurred following various routes of administration to rats. Following intravenous administration, the liver and kidney accumulated extremely high levels of the chemical. After oral administration, [14C]-malathion absorption from the stomach was slow and its excretion followed mostly the fecal route. Dermal application of [14C]-malathion may represent a high risk for exposure to the organophosphorus pesticide where the entire skin, not only the site of application, may act as reservoir for the compound.

Human factor H deficiency. Mutations in framework cysteine residues and block in H protein secretion and intracellular catabolism

The synthesis and secretion of factor H, a regulatory protein of the complement system, were studied in skin fibroblasts from an H-deficient child who has chronic hypocomplementemic renal disease. In normal fibroblasts, factor H transcripts of 4.3 and 1.8 kilobase pairs (kb) encode a 155-kDa protein containing short consensus repeat (SCR) domains 1-20 and a 45-kDa protein which contains SCRs 1-7, respectively. The patient's fibroblasts expressed normal amounts of the 4.3- and 1.8-kb messages constitutively and after tumor necrosis factor-alpha/interferon-gamma stimulation. Lysates of [35S]methionine-labeled fibroblasts from the patient contained the 155- and 45-kDa H polypeptides, but secretion of the 155-kDa protein was blocked; the 45-kDa protein was secreted with normal kinetics. The patient's plasma lacked the 155-kDa protein but contained the small form of H. Moreover, in fibroblasts the retained 155-kDa factor H protein was not degraded, even after 12 h. Immunoflourescent staining and confocal microscopic imaging of the patient's fibroblasts indicated that factor H was retained in the endoplasmic reticulum. Sequence analysis of reverse transcription-polymerase chain reaction products (the entire coding region) and genomic DNA revealed a T1679C substitution on one allele and a G2949A substitution on the other (C518R mutation in SCR 9 and C991Y mutation in SCR 16, respectively). Both mutations affect conserved cysteine residues characteristic of SCR modules and therefore predict profound changes in the higher order structure of the 155-kDa factor H protein. These data provide the first description of a molecular mechanism for factor H deficiency and yield important insights into the normal secretory pathway for this and other plasma proteins with SCR motifs.

In-vitro testicular bioactivation of acrylonitrile

The present work examines the mechanism of testicular toxicity of acrylonitrile. In testicular centrifugal fractions from Sprague Dawley rats, the metabolism of VCN to cyanide (CN-) was highest in the microsomal fraction and required NADPH for maximum activity. This biotransformation of VCN to CN- was characterized with respect to time (30 min), microsomal protein concentration (1.5 mg ml(-1)), pH (7.5) and temperature (37 degrees C). The V(max) of the reaction was 65.1 pmol CN- mg protein(-1) min(-1) and K(m) was 88.6 micromol VCN. Flushing the microsomes with carbon monoxide (CO)(4:1, CO/O2 v/v), addition of benzimidazole (1 mM) or addition of SKF 525-A (5x10(-4) M) to incubation mixtures significantly inhibited VCN metabolism by 49%, 54% and 37.4% respectively. Activation of VCN to CN- was markedly increased in microsomes obtained from phenobarbital (PB)-treated rats (128.2%). Addition of glutathione (GSH), L-cysteine, D-penicillamine or 2-mercaptoethanol significantly enhanced the release of CN- from VCN 126%, 247%, 202% and 129% of the control value respectively. These findings indicate that VCN is metabolized in the testis via cytochrome P-450 dependent mixed function oxidase system.

Propionitrile: whole body autoradiography, conventional toxicokinetic and metabolism studies in rats

The toxicokinetics, covalent binding and metabolism of propionitrile (PCN) was investigated in female Sprague-Dawley rats. For toxicokinetic studies a tracer dose of 100 microCi/Kg (11.8 mumol/Kg) [2(-14)C] PCN was injected i.v. and selected animals were sacrificed 1, 8, and 24 h post administration. Within an hour of administration peak concentration of PCN-derived radioactivity was detected in duodenum, kidney, lung, large intestine, plasma, red blood cells, stomach, heart, and brain. The treated animals excreted about 5.3% of the dose in 24 h, with approximately equal amounts in the expired air and the urine with traces in the feces. Presence of PCN-derived radioactivity up to 24 hours in the gastrointestinal tract suggests an enterohepatic recirculation of PCN and/or its metabolites. The subcellular fractions of liver duodenum and brain showed significant (p < or = 0.05) accumulation of PCN-derived radioactivity. Nuclear fraction accumulated the highest amount of radioactivity in the liver. duodenum and brain. The data indicate that PCN is readily distributed in the rat, it is metabolized to cyanide via the cytochrome P-450-dependent mixed-function oxidase system and that the direct interaction of PCN and/or its metabolites with duodenal tissues appears to be the first step in the expression of its overall toxicity. This report also shows that, for limited chemicals, whole body autoradiography combined with computer-aided imaging techniques, provides a powerful approach to preliminarily evaluate the toxicokinetic behavior of xenobiotics very quickly.

Pharmacokinetics of camptothecins administered orally

The equilibrium between lactone and salt forms of camptothecin (CPT) and its derivatives including 9-nitrocamptothecin (9-NC) depends on pH, binding to albumin and other factors. Their antitumor activity is associated with the lactone form. Our goal was the development of dosing regimens optimal for chemotherapeutic activity of the drug. The effect of p.o., i.v. and i.m. administration on the tumor uptake of [3H]-CPT or [3H]-9-NC in tumor-bearing nude mice was studied by whole-body autoradiography. In all cases, [3H]-CPT or [3H]-9-NC accumulated mainly in the gastrointestinal tract. Comparatively lower levels of drug were detected in liver, kidney, tumor, and other sites. Consistently high tumor/blood ratios following oral administration of drug suggest this route as the most effective way of treatment. Within 4 h of i.s. administration of 2 mg/kg CPT or 1 mg/kg 9-NC to mice, lactone forms were 57-81% and 47-95% of total plasma drug levels, respectively. However in plasma of humans treated p.o. with varying doses of CPT or 9-NC, lactone forms were only a minor component of total drug levels. It is concluded that ratios of lactone/total drug are much higher in mice than in humans, which influence the therapeutic efficacies these drugs in the two species.

Influence of route of administration on [3H]-camptothecin distribution and tumor uptake in CASE-bearing nude mice: whole-body autoradiographic studies

Camptothecin (CPT) inhibits the growth of a wide variety of experimental tumors. As a part of our exploration of this drug for use as a cancer chemotherapeutic agent, we studied the effect of route of administration on the absorption, distribution and tumor uptake of [3H]-CPT. The rate of disappearance of [3H]-CPT-derived radioactivity from blood during the first 48 h was highest following oral than following intravenous (i.v.) administration. Thereafter blood levels were low irrespective of route of administration. Considerable [3H]-CPT-derived radioactivity was detected in urine and feces up to 48 h after dosing. Distribution studies were conducted using quantitative whole-body autoradiography (WBA). These studies revealed that independent of the route of administration, [3H]-CPT was rapidly excreted in the bile (gallbladder) followed by elimination into the small and large intestinal tract. Levels of CPT-derived radioactivity in the kidneys were minimal and mostly localized in the renal pelvis. Hepatic concentrations of CPT were low and were almost equal to those of the tumor. The lungs of animals treated i.v. showed higher uptake of radioactivity than those treated intramuscularly or orally. Tumor/blood ratios were slightly higher following oral administration than following administration by other routes. This study indicates that CPT is primarily eliminated via the bile. The gastrointestinal tract is the major site of accumulation and excretion of CPT.

Comparative disposition of acrylonitrile and methacrylonitrile: quantitative whole-body autoradiographic studies in rats

Following intravenous administration of an equimolar (0.216 mmol/kg) radioactive dose of acrylonitrile (2-[14C]VCN, 11.5 mg/kg) or methacrylonitrile (2-[14C]MeVCN, 14.5 mg/kg), the tissue distribution, covalent interaction, and elimination were compared (at 5 min to 48 hr) in male Fischer 344 rats using whole-body autoradiography (WBA). Autoradiographs obtained from freeze-dried or acid-extracted sections of animals treated with 2-[14C]VCN showed that radioactivity accumulated in the liver, lung, bone marrow, adipose tissues, kidney, gastrointestinal tract, and spleen. In animals treated with 2-[14C]MeVCN, the respiratory tissues contained high levels of 14C at an early period (5 min), while the gastrointestinal mucosa, adrenal cortex, liver, and kidney contained high levels of radioactivity at later periods (8, 24, and 48 hr). Quantitatively, lower uptake and irreversible interactions of 14C were observed in autoradiographs of rats treated with 2-[14C]MeVCN compared with those treated with 2-[14C]VCN. Rats given 2-[14C]VCN eliminated only 27% of administered radioactivity (exhaled air, urine, and feces), whereas rats treated with 2-[14C]MeVCN eliminated, by all routes, 65% of the total radioactive dose. Both WBA and elimination studies indicated that 2-[14C]VCN and/or its metabolites were rapidly distributed, extensively bound, and slowly eliminated from tissues. 2-[14C]MeVCN and/or its metabolites, however, were rapidly distributed and eliminated, mostly via the lung. The study indicated that the substitution of a methyl group on the alpha-carbon of the alpha-beta unsaturated aliphatic nitrile VCN, to form MeVCN, imparted qualitative and quantitative differences in the disposition of these two compounds.

Role of glutathione modulation in acrylonitrile-induced gastric DNA damage in rats

Acrylonitrile (VCN) or its reactive metabolites irreversibly interact with gastric DNA in vivo and cause DNA damage. The effect of glutathione (GSH) modulation on VCN-induced genotoxicity and unscheduled DNA repair synthesis (UDRS) in DNA of gastric mucosal tissues was investigated. VCN-induced UDRS was determined: in control rats, rats with depleted gastric GSH contents, and rats treated with sulfhydryl compounds. A single oral dose (23 mg/kg) of VCN induced a time- and dose-dependent increase in gastric UDRS and decrease in GSH levels. While maximal UDRS in gastric mucosa was observed 2 h following oral administration of 23 mg/kg VCN, maximal GSH depletion (50% of control) was detected 4 h following treatment. Increasing the VCN dose to 46 mg/kg caused a further decrease in gastric GSH level (27% of control), while UDRS was elevated. Inhibition of VCN oxidation by treatment of the animals with the cytochrome P450 inhibitor, SKF 525-A, prior to VCN administration caused 65% reduction in VCN-induced UDRS. Treatment of rats with the GSH depletor diethylmaleate (DEM) prior to VCN administration caused 167% increase in UDRS in gastric mucosal tissues. Treatment of the animals with the sulfhydryl compounds, cysteine and penicillamine, prior to VCN administration protected against VCN-induced UDRS. The results demonstrated an inverse and highly significant correlation between gastric GSH levels and VCN-induced UDRS (r = -0.873, P < 0.0001). In conclusion, our study indicates that VCN bioactivation and the homeostasis of gastric GSH may play a major, role in the initial processes underlying VCN-induced gastric carcinogenesis.

Intestinal toxicity of acrylonitrile: in vitro metabolism by intestinal cytochrome P450 2E1

Acrylonitrile (VCN) is known to cause extensive gastrointestinal damage and tumors in rats. In this study the metabolism of VCN to cyanide (CN-) was characterized in the small intestinal mucosa. The majority of the metabolic reactivity was localized in the microsomal fraction and required reduced nicotinamide adenine dinucleotide phosphate for maximal activity. The intestinal metabolism of VCN to CN- was characterized with respect to VCN concentration, time, pH, and microsomal protein concentration. VCN metabolism to CN- was enhanced significantly by the addition of sulfhydryl compounds such as glutathione, cysteine, and D-penicillamine (10 mM) to 142, 161, and 189% of control, respectively. The intestinal bioactivation of VCN to CN- was enhanced by microsomes obtained from intestinal mucosa of phenobarbital (455% of control), beta-naphthoflavone (375% of control), 4-methylpyrazole (305% of control), or ethanol (165% of control)-treated rats. Addition of ethanol (80 mM) to incubation mixtures containing control or ethanol-induced microsomes resulted in significant inhibition of microsomal metabolism of VCN to CN- to 20 and 34% of control, respectively. Addition of dimethyl sulfoxide induced a similar inhibitory effect on VCN metabolism by control or ethanol-induced microsomes (8 and 26% of control, respectively). Furthermore, antibody to cytochrome P450 2E1, but not antibody to cyt P450 2B1, significantly inhibited VCN metabolism by ethanol-induced intestinal microsomes to about 25% of control. Mild inhibition (80-85% of control) of VCN metabolism was detected when antibody to cyt P450 2B1 or 2E1 was added to incubation mixtures containing Pb-induced intestinal microsomes. These findings indicate that extrahepatic tissues such as the intestinal mucosa are capable of metabolizing VCN to CN- and establish a major role of intestinal cyt P450, particularly cyt P450 2E1, in the intestinal metabolism of VCN to CN-.

Reduction in mortality associated with influenza vaccine during 1989-90 epidemic

Influenza epidemics are associated with excess winter mortality. Risk factors for influenza complications and death include chronic illness and living in residential care. In the UK uptake of influenza vaccine among high-risk groups is only 10-40%, partly because of scepticism about vaccine efficacy. We have assessed the efficacy of influenza vaccine in reducing mortality from certified influenza by a case-control study of subjects aged 16 years or older who died between Nov 4, 1989, and Feb 23, 1990, in 36 district health authorities in England. We reviewed general practitioners' records for 315 patients who died of influenza and 777 controls, matched for age, sex, and area of residence, who died a year after the epidemic. Information was collected on demography, the usual place of residence (institutional or noninstitutional), and the existence of chronic illness. Conditional logistic regression analysis for matched case-control studies showed that influenza vaccination reduced mortality by 41% (95% CI 13-60) for all subjects. Further adjustments showed that among subjects who received the vaccine for the first time in 1989, vaccination reduced mortality by 9% (0-59); however, among those who had also been vaccinated previously, mortality was reduced by 75% (31-91). We detected no significant differences in the effect of vaccine between subjects who lived in institutions and in the community (p = 0.16), or between subjects with high-risk medical conditions and those without (p = 0.76). Influenza vaccine is effective in reducing mortality from influenza, and efficacy seems to be greater after repeated annual vaccination than after first administration.

Neurologic changes in visceral leishmaniasis

Neurologic changes in visceral leishmaniasis (VL) are rarely reported. From January 1992 to April 1993, 111 patients with VL were seen at Soba University Hospital in Khartoum, Sudan. Fifty-two (46%) patients had neurologic symptoms or signs; the most common symptom was a sensation of burning feet. Four patients had foot drop. Five patients had deafness and one patient had multiple cranial nerves palsies. None of our patients had vitamin deficiency or any of the other known causes of neuropathy. Nerve conduction studies in 15 patients showed evidence of axonal degeneration and demyelination, which were confirmed by histopathology and electron microscopy of nerve biopsies. There was no direct parasitic infection of the nerve and there was no neuritis. In most patients, the sensory symptoms disappeared within two weeks in most of our patients after specific anti-leishmanial treatment. Motor recovery was much slower. Audiographic studies in five patients with deafness showed it to be sensory-neural. Hearing returned to normal after treatment with sodium stibogluconate. Further studies are needed to define the etiology of the nerve pathology in patients with VL.

Malignant hyperthermia--a case report

An acute episode of a malignant hyperthermia-like syndrome is described which occurred after suxamethonium and halothane anesthesia in a 32 year old healthy male patient undergoing a tendon repair operation to his right thumb. Dantrolene therapy rapidly reversed the life threatening signs.

Comparative metabolism and disposition of acrylonitrile and methacrylonitrile in rats

Aliphatic nitriles are a class of chemicals used in high volumes in the production of plastics and elastomers, in organic synthesis, and in production of a number of food packaging containers. Toxicity and metabolism of acrylonitrile (AN) are well characterized. On the other hand, minimal information is available on the toxicity or fate of structurally related, methacrylonitrile (MAN). In an attempt to predict the toxicity of MAN, the present studies were designed to compare the disposition of both nitriles in rats. After gavage administration of equimolar doses (0.87 mmol/kg) of 2-14C-MAN or 2-14C-AN to male F344 rats, both chemicals were well absorbed from the GI tract and distributed to all major tissues. However, major differences in the disposition of the two nitriles were observed. While approximately 39% of the administered MAN dose was eliminated as CO2 in 24 h after dosing, only 11% of an equimolar dose of AN was eliminated as such. In addition, 31% of the MAN dose was exhaled as organic volatiles in 24 h compared to less than 2% of an equivalent AN dose. MAN and acetone were identified by HPLC analysis of expired organic volatiles from MAN-treated rats. HPLC analysis showed that AN is the only organic volatile exhaled by AN-treated rats. Urinary excretion of MAN was 22% compared to 67% of an equivalent dose of AN. The major urinary metabolite from AN results from direct conjugation with GSH, whereas the major urinary metabolite from MAN results from conjugation of the epoxide with GSH.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular interaction of [2,3-14C] acrylonitrile with DNA in gastric tissue of rat

Acrylonitrile (VCN) is used extensively in polymer industries, and is known to induce gastric cancer following oral administration. A paucity of information exists regarding the mechanism(s) by which acrylonitrile induces gastric neoplasia. The time course for uptake of radioactivity by gastric tissue and covalent binding of [2,3-14C] VCN or its metabolites to gastric DNA were determined following a single oral dose of 46.5 mg/kg. The rates of DNA synthesis and repair, as measured by unscheduled DNA synthesis in the gastric tissue of VCN-treated rats, were also studied. Maximum tissue uptake and covalent binding of radioactivity to gastric DNA were observed at 15 minutes following [2,3-14C] VCN administration. At 6 hours following VCN administration, significant inhibition (37% of control) in gastric replicative DNA synthesis was observed. A rebound followed by an increase (211% of control) in replicative DNA synthesis was observed at 24 hours. A three-fold elevation in unscheduled DNA synthesis was observed at 24 hours following treatment with VCN. These results indicate that VCN or its metabolites irreversibly interact with gastric DNA, causing DNA damage. The results also indicate that the delayed VCN-induced DNA repair, determined as unscheduled DNA synthesis, is inefficient for the removal of the resulting DNA lesions.

Quantitative whole body autoradiographic disposition of glycol ether in mice: effect of route of administration

Glycol ethers such as ethylene glycol monomethyl ether (EGME) are common solvents used in many industrial products. A large number of individuals are exposed to EGME through different exposure routes. We investigated the differential distribution of EGME following various routes of administration using whole body autoradiographic (WBA) techniques. Male B6C3F1 mice were treated with tracer iv or oral doses of [2-14C]EGME (4.05 micrograms EGME/kg equivalent to 0.8 mCi/kg) and euthanized at 1 and 24 hr following treatment. In both groups of animals the highest levels of radioactivity were detected in the liver, urinary bladder, bone marrow, kidney, and epididymis, at 1- and 24-hr time periods. Computer-assisted quantitation of WBA indicated that there was markedly higher deposition of [2-14C]EGME and/or its metabolites in various tissues of the orally treated animals than in animals treated intravenously. Our studies also suggest that [2-14C]EGME is rapidly distributed either from blood or stomach to various tissues. Preferential deposition of radioactivity in the peripheral tissues of the bone, with a progressive inward accumulation in the bone marrow, was observed. Selective permeability of EGME and/or its metabolites was indicated by the higher uptake by the epididymis than that by testis. The high levels of radioactivity in biosynthetically active tissues, e.g., the liver, bone marrow, and gastric mucosa, is an indication of persistent interaction of the compound with cellular components of these tissues. These interactions may lead to EGME toxicity.

Whole-body autoradiographic disposition, elimination and placental transport of [14C]tri-o-cresyl phosphate in mice

Tri-o-cresyl phosphate (TOCP) is used commercially as a plasticizer and flame retardant. The disposition, metabolism, elimination and transplacental uptake of [phenyl-U-14C]TOCP and/or its metabolites, in pregnant and non-pregnant mice, were examined. Pregnant (18th-day gestation) and non-pregnant, ICR mice were given an i.v. dose of [14C]TOCP (557 microCi kg-1; Specified activity 4.83 microCi mumol-1). At various time intervals (1, 24, 48 and 72 h) the animals were processed for whole-body autoradiography (WBA). Over 72 h the non-pregnant mice excreted 55% of the 14C in the urine and 9% in the feces, while excretion in the urine and feces by the pregnant mice was 50% and 9% of the total dose, respectively. The WBA and its computer-assisted image analysis indicated extensive distribution of the 14C label originally dosed as [14C]TOCP in pregnant mice and their fetuses. The retention of radioactivity in organs such as lung, spleen, gall-bladder and liver of mother and its fetuses suggest that these are the target sites of TOCP toxicity. The distribution in non-pregnant and pregnant mice and in the fetal tissues followed a similar pattern in uptake and retention until 72 h. Brain and spinal cord had the least amount of [14C]TOCP. This finding may support reports that explain the insensitivity of the mice towards organophosphate-induced delayed neurotoxicity (OPIDN) of TOCP.

Effect of glutathione modulation on molecular interaction of [14C]-chloroacetonitrile with maternal and fetal DNA in mice

Binding of haloacetonitriles or their reactive metabolites to macromolecules of fetal tissue may be responsible for reproductive toxicity. To investigate the role of glutathione (GSH) in the metabolism and reproductive toxicity of haloacetonitriles, irreversible interaction of chloroacetonitrile (CAN) with maternal uterine and fetal DNA was assessed in a time course study among normal and among glutathione-depleted mice treated with [2-14C]-CAN. GSH was depleted in maternal and fetal tissues by treating of animals with diethylmaleate (DEM) 1 h before [2-14C]-CAN administration. Maternal urinary excretion of thiocyanate was 5 times higher in glutathione-depleted mice than in controls. At 8 and 24 h following [2-14C]-CAN administration, total radioactivity uptake in maternal uterine tissue, amniotic fluid, and fetal tissue was higher in glutathione-depleted mice than in control. Also the interaction of CAN or its reactive metabolites with maternal uterine DNA was enhanced following glutathione depletion. At 24 h after treatment, the covalent binding to DNA in fetal tissue was significantly increased in glutathione depleted mice (205% of control). The magnitude of interaction of CAN in fetal DNA was about 4 times higher than that in uterine DNA. The time course study in either maternal uterine or fetal DNA revealed elevated and persistent levels of covalent binding of [ C]-CAN to DNA at 72 h after treatment. Enhancement of the molecular interaction of CAN in maternal and fetal DNA following GSH depletion indicates an important role for GSH in CAN metabolism.

Pulmonary toxicity of acrylonitrile: covalent interaction and effect on replicative and unscheduled DNA synthesis in the lung

Acrylonitrile (VCN)-induced lung toxicity was studied following a single oral dose (46.5 mg/kg). The mechanism of toxic injury was investigated by assessing the covalent interaction of [2,3-14C]VCN with pulmonary DNA. The effect of the same dose on replicative DNA synthesis and repair in the lungs of treated rats was also investigated. Histologic examination revealed that lungs of VCN-treated animals showed moderate to marked hyperplasia of the Clara cells lining the bronchioles. [14C]Lung tissue uptake was extremely fast, having a maximum at 0.5 h after treatment (150 DPM tissue). Radioactivity in lung tissue declined gradually as a function of time, but was still detected at 72 h after treatment (59 DPM/mg tissue). Covalent binding of [14C]VCN-derived radioactivity to pulmonary DNA was time-dependent, reaching a maximum at 12 h following treatment (61 DPM/mg DNA) and was still detected at 72 h (27 DPM/mg DNA) indicating the incomplete removal of radioactivity covalently bound to DNA. Replicative DNA synthesis in lung tissue was significantly decreased at all time points studied (59, 55 and 72% of control at 0.5, 6 and 24 h, respectively). The DNA repair in the lung was increased by 2-fold at 0.5 h and 1.6-fold at 6 h following VCN oral treatment. The histologic and biochemical results presented in this study provide evidence for the acute genetic toxicity of VCN (and/or its metabolites) in lung tissue following a single oral dose of VCN.

Ornithine decarboxylase activity in tumor and normal tissue of head and neck cancer patients

Tumorigenesis requires increased biosynthesis of polyamines and elevated levels of ornithine decarboxylase, which is the rate-limiting enzyme in the polyamine synthesis pathway. Previous animal studies have noted a marked increase in ornithine decarboxylase after exposure to tumorigenic stimuli and that pretreatment with vitamins A and E provides protection against the carcinogenic action. However, studies of ornithine decarboxylase activity in human oral cavity carcinoma have not been as specific. The goal of this study was to determine whether a specific difference in ornithine decarboxylase activity occurs in tumor versus adjacent normal tissue in head and neck squamous cell carcinoma patients. Ornithine decarboxylase activity was measured in 30 consecutive head and neck cancer patients undergoing surgical therapy. Ornithine decarboxylase levels were found to be significantly elevated in tumor tissue samples when compared to adjacent normal mucosa samples (P less than .004). This finding confirms the previous findings noted in animal models and implies that the protective effects of vitamins A and E will extend to human head and neck cancers.

Purification and characterization of RHP (factor H) and study of its interactions with the first component of complement

RHP has been purified from the plasma of both normal individuals and patients with rheumatoid arthritis (RA). RHP from both these sources was shown to be identical with Factor H by reaction with antisera and N-terminal amino acid sequence analysis. Factor H, from both normal and RA sera, inhibited the solubilization of immune precipitates but did not affect prevention of immune precipitation. Factor H was shown to inhibit the haemolytic activity of fluid-phase C1, but unlike C1-inhibitor, it had little effect on C1 bound to EA (EAC1). Factor H was shown to complex with intact C1, to isolated C1q and to the C1r:C1s tetramer. However, binding of factor H to C1 did not dissociate the C1 macromolecule. A C1-Factor H complex was detected in the serum and plasma from normal individuals and patients with systemic lupus erythematosus and RA. Serum levels of this complex were reduced, by EDTA-treatment of serum and by activation of complement by the classical pathway.

Studies on the mechanism of acetonitrile toxicity. I: Whole body autoradiographic distribution and macromolecular interaction of 2-14C-acetonitrile in mice

Acetonitrile, a commonly used solvent is known to cause central nervous system dysfunctions. In order to gain an insight onto the mechanism of acetonitrile toxicity, we studied the kinetics of acetonitrile distribution in mice. Male ICR mice were given a tracer dose of 2-14C-acetonitrile intravenously (60 mu mol/kg or 684 mu Ci/kg, spec. act. 11.4 mCi/mmol). At various time intervals (5 min., 0.5, 1, 4, 8, 24 and 48 hr) after treatment, mice were anaesthetized and frozen by immersion in a dry ice/hexane mixture, or they were dissected for collection of organs and tissues. Frozen mice were processed for whole body autoradiography, which allows the detection of non-volatile metabolites of acetonitrile at their sites of accumulation. Covalent binding of acetonitrile metabolites in tissues was determined using trichloroacetic acid followed by ethanol/ether extraction techniques. Whole body autoradiography revealed heavy localization of acetonitrile metabolites in the gastrointestinal tissues and bile. At 5 min., the highest levels of radioactivity occurred in the liver and kidney; levels declined over time. At 24 and 48 hr, acetonitrile derived radioactivity were detected in the gastrointestine, thymus, liver and male reproductive organs. Covalent binding studies at 24 and 48 hr after treatment indicated that 40-50% of the total radioactivity present in the liver was bound to the macromolecular fractions of the tissues. The radioactivity contents of other organs were, in large part (40-50% of total), present in the lipid fraction of the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylonitrile interaction with testicular DNA in rats

In the present study we report the in vivo interaction of acrylonitrile (VCN) with testicular tissue in rats. Covalent binding of radioactivity to testicular tissue DNA was examined for a period of 72 hr after a single oral dose (46.5 mg/kg) of [2,3-14C] VCN. Maximal covalent binding was observed at 0.5 hr (8.9 mumol VCN equivalent/mol nucleotide). Binding decreased gradually thereafter but was still detected (2.5 mumol VCN equivalent/mol nucleotide) at 72 hr following VCN administration. Further, we examined the effects of VCN on DNA synthesis and repair in the testes of rats following a single oral dose (46.5 mg/kg) of VCN to clarify the impact of the covalent binding observed on the testicular genetic material. A significant decrease in DNA synthesis (80% of control) was observed at 0.5 hr after treatment. At 24 hr following acrylonitrile administration, testicular DNA synthesis was severely inhibited (38% of control). Testicular DNA repair was increased 1.5-fold at 0.5 hr and more than 3.3-fold at 24 hr following treatment with VCN. These results suggest that VCN can act as a multipotent genotoxic agent by alkylating DNA in testicular tissue and may affect the male reproductive function by interfering with testicular DNA synthesis and repair processes.