Morphological effects of neuropathy-inducing organophosphorus compounds in primary dorsal root ganglia cell cultures

Chick embryo dorsal root ganglia (DRG) cultures were used to explore early pathological events associated with exposure to neuropathy-inducing organophosphorus (OP) compounds. This approach used an in vitro neuronal system from the species that provides the animal model for OP-induced delayed neuropathy (OPIDN). DRG were obtained from 9-day-old chick embryos, and grown for 14 days in minimal essential medium (MEM) supplemented with bovine and human placental sera and growth factors. Cultures were then exposed to 1 microM of the OP compounds phenyl saligenin phosphate (PSP) or mipafox, which readily elicit OPIDN in hens, paraoxon, which does not cause OPIDN, or the DMSO vehicle. The medium containing these toxicants was removed after 12 h, and cultures maintained for 4-7 days post-exposure. Morphometric analysis of neurites was performed by inverted microscopy, which demonstrated that neurites of cells treated with mipafox or PSP but not with paraoxon had decreased length-to-diameter ratios at day 4 post-exposure. Ultrastructural alterations of neurons treated with PSP and mipafox included dissolution of microtubules and neurofilaments and degrading mitochondria. Paraoxon-treated and DMSO control neuronal cell cultures did not show such evident ultrastructural changes. This study demonstrates that chick DRG show pathological changes following exposure to neuropathy-inducing OP compounds.     

Histopathological alterations and functional brain deficits after transient hypoxia in the newborn rat pup: a long term follow-up

To assess temporal brain deficits consecutive to severe birth hypoxia, newborn rats were exposed for 20 min to 100% N2. This treatment induced a long-term growth retardation and a delayed, but only transient, neuronal loss (approximately 25%) in the CA1 hippocampus and parietal cortex, starting from 3 days and peaking at 6 days post-hypoxia. The expression profiles of various apoptosis-regulating proteins (including Bcl-2, Bax, p53 and caspase-3) were well correlated to the alterations of nuclear morphology depicted by 4,6-diamidino-2-phenylindole (DAPI). Whereas they confirmed a gradual histological recovery, specific DNA fragmentation patterns suggested that birth hypoxia may transiently reactivate the developmental programme of neuronal elimination. Although they successfully achieved various behavioral tests such as the righting reflex, negative geotaxis, locomotor coordination, and the eight-arm maze tasks, both developing and adult hypoxic rats were repeatedly slower than controls, suggesting that birth hypoxia is associated to moderate but persistent impairments of functional capacities.     

Cylindrocarcinoma in a patient with Brooke-Spiegler syndrome

BACKGROUND: Cutaneous cylindromas are benign adnexal tumors that may occur as a solitary lesion or in a multiple familiar pattern. Malignant change is rare. The association of multiple trichoepitheliomas and cylindromas, the so called Brooke-Spiegler Syndrome, is supposed to be inherited in an autosomal dominant manner. PATIENTS: A 55 year old woman presented with multiple skin tumors on the scalp, as well as the nasolabial and periauricular area since the age of 20 years. Her daughter and her nephew were also affected. Tumors were surgically removed for cosmetic reasons and showed histological signs of benign cylindromas and trichoepitheliomas. 35 years after diagnosis patient presented with a large exulceration on the right occipital area with intracranial invasion. Staging revealed multiple metastases in both lungs. Patient died 1 month later. RESULTS: Histological examination showed beside zones of massive necrosis multiple mitosis. The jigsaw puzzle pattern and the thick PAS positive basal layer, the striking characteristics of benign cylindromas, were lost. These histological findings and the clinical presentation led to the diagnosis of cylindrocarcinoma. CONCLUSIONS: Cylindrocarcinoma is an aggressive tumor with tendency to a local destructive growth and metastases. As malignant transformation of a benign cylindroma occurs more often in the multiple form a close follow-up of patients with multiple cylindromas is necessary. A family study is indicated.     

TP53 polymorphism at exon 4 in caucasian women from eastern France: lack of correlation with HPV status and grade of cervical precancerous lesions

OBJECTIVE: To investigate the codon 72 TP53 polymorphism in women from eastern France with normal or abnormal cervical cytology.STUDY DESIGN: We analyzed the TP53 allele distribution by denaturant gradient gel electrophoresis assay and the human papillomaviruses (HPV) infection in 138 cervical smears: 50 normal, 20 atypical squamous cells of undetermined significance, 40 low grade squamous intraepithelial lesions, 28 high grade squamous intraepithelial lesions.RESULTS: The viral DNA prevalence increased with cytological abnormalities. The rates of arginine (Arg) and proline (Pro) homozygosity and Arg/Pro heterozygosity were 49, 0.72, and 51%, respectively. No association was found between HPV status and TP53 polymorphism. No differences were observed in the frequency of the TP53 genotypes according to cytology.CONCLUSION: The TP53 Arg/Arg genotype does not appear to represent a risk factor in the progression of HPV associated cervical lesions. We were not able to confirm that the TP53 genotype increases the susceptibility to be infected by HPV or to develop HGSIL, and a fortiori invasive carcinoma of the cervix.     

In vitro reversal of chloroquine resistance in Plasmodium falciparum with dihydroethanoanthracene derivatives

The effects of combining four dihydroethanoanthracenic (DEA) derivatives and chloroquine were assessed in vitro against Plasmodium falciparum chloroquine resistant parasites W2, Palo Alto, FCR3, and Bres1. Like verapamil or promethazine, the four dihydroethanoanthracenic derivatives tested can be added to the growing list of agents that show capability in enhancing the activity of chloroquine against resistant parasites. The structurally related tricyclic antihistaminic compounds examined in this study exerted different intrinsic antimalarial activity, but the same chloroquine-potentiating activity as verapamil or promethazine. They may act both on the rate of chloroquine accumulation and on its access to ferriprotoporphyrin IX. The reversal mechanism would be assumed to result from competition between DEA derivatives and chloroquine for efflux translocation sites, thus causing an increase in steady-state accumulation of chloroquine and a return to susceptibility. Restoration of therapeutic efficacy of chloroquine against resistant parasites by the administration of an additional drug available at relatively low cost may be a more effective strategy than the introduction of another antimalarial drug at the national level.     

Measurement of absolute values of hemoglobin oxygenation in the brain of small rodents by near infrared reflection spectrophotometry

Reflection near infrared spectroscopy (reNIRS) has been proposed as a novel technique for the measurement of absolute values of total hemoglobin (tHb), oxygenated hemoglobin (oxHb), hemoglobin saturation (SO2), and cytochrome aa3 oxidation status (oxCyt aa3) in living tissue. In this study, we evaluated reNIRS during physiological cerebral blood flow conditions in rats (n=6) and during the induction of global cerebral ischemia in gerbils (n=6). ReNIRS parameters were assessed over the exposed cerebral cortex and compared to regional cerebral blood flow (rCBF) data obtained by laser Doppler flowmetry. Under physiological conditions, reNIRS measurements reflected the large intra- and interindividual variability of oxHb and tHb in the brain. The absolute values obtained by reNIRS for tHb (6.3 +/- 1.7 mg/ml), oxHb (3.7 +/- 1.1 mg/ml), and SO2 (61 +/- 5%) matched expected values. In contrast, measurements of oxCyt aa3 were unstable and results unreliable. reNIRS reliably detected cerebral ischemia, verified by a reduction of rCBF to 11% of baseline. tHb dropped to 74 +/- 7% of baseline (P<0.001), reflecting ischemic microvascular vasoconstriction. oxHb and SO2 dropped to expected near-zero values (2 +/- 4 and 3 +/- 5% of baseline, respectively; P<0.001). We conclude that reNIRS provides reliable and reproducible absolute values for brain tissue tHb, oxHb, and SO2 in small rodents. Determination of physiological values requires measurements at multiple locations, while cerebral ischemia is reliably detected by continuous recordings at a single location.     

Variation in Routine Psychiatric Workload: The Role of Financing Source,Managed Care Participation,and Mental Health Workforce Competition

This study was conducted to examine the association between psychiatrists' demographic characteristics, payment source, and managed care participation and psychiatrists' practice workload, and between the supply of other mental health providers in a psychiatrist's county of practice and psychiatrists' practice workload. Data from the 1996 American Psychiatric Association National Survey of Psychiatric Practice were merged with national countywide measures of mental health workforce and environmental data from the 1996 Area Resource File. In comparison to male psychiatrists, female psychiatrists treat fewer patients per week, provide less total hours of weekly patient care, and obtain fewer new monthly referrals. An increase in psychiatrists' managed care participation was associated with only minor increases in the number of patients per week, weekly time spent in clinical care, and number of new monthly referrals. The supply of other mental health providers was not associated with variation in practice workload. Once psychiatrists participate in managed care plans, an increase in their participation rate does not significantly expand clinical practice workload. The supply of other mental health providers was not significantly associated with variation in psychiatrists' workload, which suggests that substitution effects may not be evident with this aspect of psychiatric practice.     

Policy Intervention

This paper addresses market failure due to externalities, as well as information asymmetries and public policy problems that need to be solved to ensure high quality care for affective disorders. We delineate the problems in parity legislation, managed care, as well as Medicare and Medicaid that need to be addressed to reduce the burden of illness affective disorders. A research agenda is developed for formulating and implementing public policy.