Events that precede and that follow S-(1,2-dichlorovinyl)-L-cysteine-induced release of mitochondrial Ca2+ and their association with cytotoxicity to renal cells.

Previous studies showed that S-(1,2-dichlorovinyl)-L-cysteine perturbs intracellular Ca2+ homeostasis [Vamvakas et al., Mol Pharmacol 38: 455-461, 1990]. The objective of the present study was to investigate the cellular events that precede and that follow S-(1,2-dichlorovinyl)-L-cysteine-induced mitochondrial Ca2+ release. In incubations with isolated kidney mitochondria, S-(1,2-dichlorovinyl)-L-cysteine-induced Ca2+ efflux is preceded by increased oxidation of mitochondrial pyridine nucleotides and is prevented by ATP, an inhibitor of the hydrolysis of pyridine nucleotides, and by meta-iodobenzylguanidine, an acceptor of ADP-ribose moieties. In LLC-PK1 cells, elevation in the cytosolic Ca2+ concentration is followed by a several-fold increase in DNA double-strand breaks which is attributed to the activation of Ca2+- and Mg(2+)-dependent endonucleases. The formation of DNA double-strand breaks is followed by increased poly(ADP-ribosylation) of nuclear proteins. S-(1,2-Dichlorovinyl)-L-cysteine-induced cytotoxicity in LLC-PK1 cells is blocked by chelation of cytosolic Ca2+ with Quin-2, by inhibition of DNA fragmentation with aurintricarboxylic acid and by inhibition of increased poly(ADP-ribosyl)transferase activity by 3-aminobenzamide. These findings indicate that S-(1,2-dichlorovinyl)-L-cysteine bioactivation in renal cells may initiate the following cascade of events: increased oxidation and hydrolysis of mitochondrial pyridine nucleotides resulting in the modification of mitochondrial membrane proteins by pyridine nucleotide-derived ADP-ribose moieties, followed by Ca2+ release. Elevated Ca2+ concentrations may activate Ca(2+)-dependent endonucleases, which leads to DNA fragmentation followed by increased poly(ADP-ribosylation) of nuclear proteins and, finally, cytotoxicity.     

Changes in the classification of carcinogenic chemicals in the work area

Carcinogenic chemicals in the work area are currently classified into three categories in section III of the German List of MAK and BAT Values (list of values on maximum workplace concentrations and biological tolerance for occupational exposures). This classification is based on qualitative criteria and reflects essentially the weight of evidence available for judging the carcinogenic potential of the chemicals. It is proposed that these categories – IIIA1, IIIA2, IIIB – be retained as Categories 1, 2, and 3, to correspond with European Union regulations. On the basis of our advancing knowledge of reaction mechanisms and the potency of carcinogens, these three categories are supplemented with two additional categories. The essential feature of substances classified in the new categories is that exposure to these chemicals does not contribute significantly to risk of cancer to man, provided that an appropriate exposure limit (MAK value) is observed. Chemicals known to act typically by nongenotoxic mechanisms and for which information is available that allows evaluation of the effects of low-dose exposures, are classified in Category 4. Genotoxic chemicals for which low carcinogenic potency can be expected on the basis of dose-response relationships and toxicokinetics, and for which risk at low doses can be assessed are classified in Category 5. The basis for a better differentiation of carcinogens is discussed, the new categories are defined, and possible criteria for classification are described. Examples for Category 4 (1,4-dioxane) and Category 5 (styrene) are presented.     

2-Acetylpyridine thiosemicarbazones XI: 2-(alpha-Hydroxyacetyl)pyridine thiosemicarbazones as antimalarial and antibacterial agents

A series of 2-(alpha-hydroxyacetyl)pyridine thiosemicarbazones was synthesized as potential antimalarial and antibacterial agents. Their synthesis was achieved by the condensation of N4-mono- or N4,N4-disubstituted thiosemicarbazides with 2-(alpha-hydroxyacetyl)pyridine. The latter was prepared by selective bromine oxidation of (2-pyridinyl)-1,2-ethanediol. The new compounds show potent inhibitory activity against penicillin-sensitive as well as penicillin-resistant Neisseria gonorrhoeae (MIC, 0.5-0.004 micrograms/mL), against Neisseria meningitidis (MIC, 0.5-0.032 micrograms/mL), and Staphylococcus aureus (MIC, 0.5-2 micrograms/mL). Good in vitro antimalarial effects against Plasmodium falciparum (Smith strain; ID50, 6.7-38 ng/mL) were observed in most of these new agents, but only 3 of 12 compounds exhibit moderate in vivo activity against Plasmodium berghei. These new agents appear to be less toxic to the host and more water soluble than the corresponding 2-acetylpyridine thiosemicarbazones.     

Management of the child with a learning disorder

The label "learning disabilities" is all-embracing; it describes a syndrome, not a specific child with specific problems. Parent involvement in and collaboration with pediatricians and schools in navigating service systems, accessing appropriate services, and case management are particularly relevant for children with LD. Comprehensive service delivery in school settings requires the interface of other service sectors, such as primary care, mental health,and other community agencies that also recognize and address children's problems. To date, marked differences exist among the assessment, classification and diagnostic, and treatment practices of these service systems, despite the fact that they address the same patient population--school-aged youth. Additionally, many of these agencies and systems operate in isolation with limited cross-sector communication or service collaboration. Parent involvement and advocacy, with assistance from pediatricians and knowledgeable school personnel, is necessary to ensure that appropriate resources available from these sectors are well coordinated and provided for children with an LD to improve their school performance and ongoing educational experience.     

Susceptibility of GTR-regenerated periodontal attachment to ligature-induced periodontitis

AIM: This study aimed to compare the susceptibility of guided tissue regeneration (GTR)-regenerated periodontal attachment to ligature-induced periodontitis with that of the pristine periodontium. METHODS: Periodontal breakdown was produced in four monkeys by the placement of orthodontic elastics around experimental teeth (test teeth). During a flap operation, the root surfaces were scaled and planed, and a notch indicating the apical termination of scaling and root planing was made in the root surface. Following resection of the crowns and endodontic treatment, an e-PTFE membrane was adapted over the roots. Subsequently, the flaps were sutured to complete closure of the wound (submerged). At membrane removal after 5 weeks, the crowns of the contralateral teeth serving as controls were resected, and the roots treated endodontically during a flap operation. Artificial composite crowns were then placed on both test and control roots. After 3 months of tooth cleaning, cotton floss ligatures were placed passively around both test and control teeth for a period of 6 months. Two weeks later the animals were sacrificed. RESULTS: Histological analysis demonstrated that the instrumented root surfaces of the test teeth were covered by newly formed cementum of the reparative, cellular, extrinsic and intrinsic fiber type, while the cementum on the controls was mainly acellular extrinsic fiber cementum. Histometric assessments demonstrated that similar attachment loss had occurred on test (1.0+/-0.5 mm) and control roots (1.0+/-0.4 mm) during the 6 months of ligature-induced plaque accumulation. CONCLUSION: The results indicate that teeth with a periodontal attachment apparatus formed by GTR is not more susceptible to periodontitis than those with a pristine periodontium.     

Proceedings of a consensus conference: the screening of blood donors for variant CJD

Since the identification, in 1996, of the first case of variant Creutzfeldt-Jakob disease (vCJD) in humans various approaches have been implemented and/or proposed to prevent this disease from being transfusion transmitted. In addition, a variety of possible laboratory-based approaches have been developed and will continue to be developed for the vCJD screening of blood donors. Various issues related to the implementation of such vCJD testing is likely to assume greater importance as diagnostic tests for vCJD becomes available for the potential screening of blood donors. The purpose of this Consensus Conference was to bring together international experts in an effort to determine which principles should guide the introduction of such testing. These experts provided the scientific and biological background of bovine spongiform encephalopathy (BSE) and vCJD, an understanding of their current epidemiology, as well as the ethical and legal issues that would impact on the implementation of a screening test for preventing the transfusion transmission of vCJD. This contentious issue is of potential considerable importance to transfusion medicine personnel worldwide, as well as to future recipients of allogeneic blood components.     

The concurrence of microalbuminuria and retinopathy with cardiovascular risk factors; reliable predictors of asymptomatic coronary artery disease in type 2 diabetes

People with diabetes mellitus type 2 (DM2) have a greater risk for premature morbidity and mortality due to cardiovascular disease than the general population: cardiovascular disease accounts for 75% of deaths in this population group. We examined whether or not the association of clinical cardiovascular risk factors (RF) with both microalbuminuria (MA) and diabetic retinopathy (DR) constitutes reliable evidence for the existence of asymptomatic coronary artery disease (CAD), as assessed by positive myocardial thallium scintiscan using the SPECT method (Tl-scan) in patients with DM2. The study included 76 individuals with DM2 (54 men and 22 women, aged 46-70 years), with a negative history for infarction and negative clinical or ECG findings of CAD. In all patients, 3 overnight (11 pm - 7 am) urine collections were made for evaluation of MA. Fundoscopy after dilatation and a Tl-scan (reference method) were also carried out. In addition, blood pressure and waist/hip ratio were measured and smoking habits were recorded. In the 35 patients with a positive Tl-scan (46%) a higher (p<0.001) incidence of MA, DR, hypertension, smoking and higher waist/hip ratio were detected. Of the 16 patients with concurrent presence of MA and DR, 15 had a positive Tl-scan (94%), whereas the Tl-scan was negative in 30/36 (83%) patients with absence of both MA and DR. One or no cardiovascular RF in the absence of MA and DR increased the prediction of a negative Tl-scan to 100% (NPV: 1.00). Based only on history, fundoscopy and MA testing, and without resorting to expensive and laborious testing procedures, it is possible to safely distinguish patients with type 2 diabetes, who require no further investigations for asymptomatic CAD.     

MIB1 as a possible predictor of recurrence in low-grade endometrial stromal sarcoma of the uterus

OBJECTIVE: Immunohistochemical analysis of MIB1, p53, estrogen, and progesterone receptors can provide prognostic information in endometrial adenocarcinoma. Since predictors of recurrence for low-grade endometrial stromal sarcoma (LESS) are still unknown, a battery of immunostains was performed to find markers, which might be useful to predict prognosis. METHODS: Eleven patients with an average age of 43.8 years (range 27-76) were identified with stage I LESS. Immunostains, including MIB1, p53, ER, and PR, were evaluated by two pathologists, independently. RESULTS: All tumors were positive for ER and PR; 1/11 was positive for p53; MIB1 ranged from 0 to 20% positive tumor nuclei. Mitotic counts ranged from 0 to 7/10 hpf. Two patients developed recurrences. One had a pelvic recurrence 7 years after diagnosis. This tumor had a mitotic count of 1/10 hpf, MIB1 expression in 10% of nuclei, and focal p53 expression. A second patient developed pulmonary metastases 10.8 years after diagnosis; the tumor showed a mitotic count of 7/10 hpf and MIB1 expression in 20% of nuclei, but was negative for p53. There was a significant difference in MIB1 reactivity scores between patients who did or did not develop recurrence (P = 0.0303). A marginally significant association was detected between MIB1 (P = 0.0896) or p53 (P = 0.0833) positivity and length of recurrence-free survival. CONCLUSION: Although MIB1 and p53 appear to be useful prognostic markers, a larger study would be necessary to confirm their validity.     

Greek McGill Pain Questionnaire: validation and utility in cancer patients

In 1968, Melzack and Casey suggested that there are three major psychological dimensions of pain: sensory, affect, evaluative. These categories interact with one another to provide quantitative and qualitative information on the components of pain. In 1975, Melzack developed the McGill Pain Questionnaire, which is composed of four major parts and evaluates the qualities of pain. The aim of this study was to assess the applicability, reliability, and validity of the McGill Pain Questionnaire on a sample of Greek cancer patients receiving palliative treatment. It was administered to 114 cancer patients before the initiation of the palliative treatment, and then to 80 cancer patients during the treatment 7 days later. The results indicated that scale reliability was very good (0.95-0.97). During the pretreatment period, correlations between Present Rating Index (PRI), Present Pain Intensity (PPI), and Number of Words Chosen (NWC) ranged between 0.42 and 0.92. During the post-treatment time, the correlations ranged between 0.28 and 0.91. Only 21.8% of the words met a criterion of 30% for representativeness on the first administration of the questionnaire, and 9% met this criterion on the second. Validity was satisfactory (P < 0.005) according to "responsiveness to changes in time", as there was a statistical difference between the pretreatment and post-treatment time. Patients presented a desirable level of convergent construct validity (P < 0.05) concerning their performance status. Exploratory factor analysis was examined and two factors with eigenvalue over 1 were extracted, and they accounted for 95.2% of the variance. These results support the Greek-MPQ as a reliable and valid measure for evaluating the qualities of cancer pain in patients receiving palliative care.     

Radiotherapy in conjunction with intravenous infusion of 180 mg of disodium pamidronate in management of osteolytic metastases from breast cancer: clinical evaluation,biochemical markers,quality of life,and monitoring of recalcification using assessments of gray-level histogram in plain radiographs

PURPOSE: To evaluate the clinical improvement and radiographically monitor the effect of local radiotherapy in conjunction with disodium pamidronate (DP) on metastatic osteolytic disease. METHODS AND MATERIALS: Thirty-three patients with osteolytic metastasis from advanced breast cancer received radiotherapy with a 6-MV linear accelerator up to a dose of 30 Gy (3 Gy/fraction, 5 d/wk) combined with 24 monthly sessions of a 180-mg DP infusion. Conventional X-rays were obtained during the first six sessions of DP treatment, retaining the same settings for each exposure. The analysis of the image attributes was based on measuring the first-order statistics of the mean value and energy of gray-level histograms in the osteolytic region. RESULTS: The 6-month measurements compared with baseline showed statistically significant differences (p < 0.01, Wilcoxon test) in energy of gray-level histogram (-10.8%), mean value of gray-level histogram (+9.5%), pain score (-5.8 points), Eastern Cooperative Oncology Group status (-2.4 points), urine hydroxyproline/creatinine ratio (-41.7%), urine calcium/creatinine ratio (-58.8%), and bone alkaline phosphatase (-42.4%). Quality of life as determined by the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire (version 3) also improved. During follow-up, 88% of patients had complete and 12% partial responses (International Union Against Cancer radiologic criteria). On multivariate analysis, greater changes in the mean value of the gray-level histogram and negative nodal status were predictors for a reduction in the number of skeletal complications after therapy. Flu-like syndrome occurred in 13 patients (39%) and was well managed with mild antipyretics. CONCLUSION: Image-processing in plain radiographs offers an objective way to assess recalcification. The image-processing indexes, along with the measurements of performance status, quality of life, and biochemical markers, improved significantly. Local radiotherapy combined with long-term high-dose DP up to 180 mg is tolerable and has a high therapeutic response.