Cloning and characterization of cyclooxygenase-1b (putative cyclooxygenase-3) in rat

A splice variant of cyclooxygenase-1 (COX-1), COX-1b (previously termed as COX-3), has been identified in canine tissues as an acetaminophen-sensitive isoform, but the sequence of COX-1b mRNA and the encoded protein are not known in rats. We cloned and sequenced rat COX-1b mRNA from cerebral endothelial cells. Sequence analysis indicated that the 98-base pair intron-1 of COX-1 gene remains unprocessed in the COX-1b mRNA, causing a frameshift mutation and a 127-amino acid open reading frame with no sequence similarity with known cyclooxygenases. Transient and permanent transfection of COS-7 cells with a vector containing the rat COX-1b cDNA resulted in synthesis of a protein of the expected size. We generated an affinity-purified polyclonal antibody against the rat COX-1b protein. Western blot analysis of rat tissues using this antibody demonstrated the likely existence of rat COX-1b protein in vivo with the highest expression in heart, kidney, and neuronal tissues. Our results on both stable and on transiently transfected COS-7 cells suggest that rat COX-1b does not have cyclooxygenase activity and does not have any effect on the inhibition of prostaglandin production by acetaminophen. Because this protein has a completely different amino acid sequence than COX-1 and COX-2 and it does not have cyclooxygenase activity, we suggest a name cyclooxygenase variant protein to distinguish it from the known prostaglandin-synthesizing cyclooxygenase isoforms.     

Pentapeptides derived from Abeta 1-42 protect neurons from the modulatory effect of Abeta fibrils--an in vitro and in vivo electrophysiological study

Short fragments and fragment analogues of beta-amyloid 1-42 peptide (Abeta1-42) display a protective effect against Abeta-mediated neurotoxicity. After consideration of our earlier results with in vitro bioassay of synthetic Abeta-recognition peptides and toxic fibrillar amyloids, five pentapeptides were selected as putative neuroprotective agents: Phe-Arg-His-Asp-Ser amide (Abeta4-8) and Gly-Arg-His-Asp-Ser amide (an analogue of Abeta4-8), Leu-Pro-Tyr-Phe-Asp amide (an analogue of Abeta17-21), Arg-Ile-Ile-Gly-Leu amide (an analogue of Abeta30-34), and Arg-Val-Val-Ile-Ala amide (an analogue of Abeta38-42). In vitro electrophysiological experiments on rat brain slices demonstrated that four of these peptides counteracted with the field excitatory postsynaptic potential-attenuating effect of Abeta1-42; only Arg-Val-Val-Ile-Ala amide proved inactive. In in vivo experiments using extracellular single-unit recordings combined with iontophoresis, all these pentapeptides except Arg-Val-Val-Ile-Ala amide protected neurons from the NMDA response-enhancing effect of Abeta1-42 in the hippocampal CA1 region. These results suggest that Abeta recognition sequences may serve as leads for the design of novel neuroprotective compounds.     

Child and adolescent suicides in Virginia: 1987 to 2003

OBJECTIVES: The aim of this study was to better understand suicides in children and adolescents using records from the Office of the Medical Examiner of Virginia from 1987 to 2003. MAIN FINDINGS, KEY DATA, AND STATISTICS: Suicide accounted for 16.8% of unnatural deaths. Suicide rates were highest for Caucasians. Guns were the most common method of death for suicides, followed by hanging and poisoning. Poisoning other than carbon monoxide accounted for 7.8% of suicides, with tricyclic antidepressants (TCAs) the most identifiable poison. Female youths were 10 times more likely to die from TCAs than male youths, after adjusting for race and age. CONCLUSIONS: Guns and hanging were the principal methods of suicide. Among the antidepressants, TCAs have been the most common poisons used in suicide. Increasing age was a powerful determinant of suicide. Some patients may have stockpiled their TCAs for a while before their TCA overdose. Other suicide victims may have used TCA supplies from family members. Hence, some of the suicide victims may not have taken TCAs on a regular basis before committing suicide. Further exploration of TCA-induced suicidal thoughts is needed. Conclusions cannot be made at the time about the precise role that TCAs played in TCA-induced suicide reported in our study.     

Body mass index (BMI) in newly admitted child and adolescent psychiatric inpatients

INTRODUCTION: Obesity is a major problem among children and adolescents suffering from chronic mental illness. State-of-the-art measures such as body mass index (BMI) and growth-related weight charts are now readily available to clinicians and investigators interested in psychotropic drug-associated weight gain in the pediatric population. However, no reports that utilize such measures in large series of children and adolescents with psychiatric disorders are available. METHODS: The authors employed the Nutstat module of the Centers for Disease Control and Prevention (CDC) Epi Info software to assess BMI in a psychiatry inpatient child and adolescent population in Central Virginia. The authors also developed a scoring system to relate psychotropic administration to BMI. RESULTS: Children and adolescents with chronic mental illness had greater BMI measurements than the general pediatric population. Our scoring system found a relationship between antipsychotic drug administration and increased BMI that almost reached a level of significance (p=0.062). CONCLUSIONS: The present methodology using absolute weight to assess psychotropic drug-associated increase in body weight for children and adolescents is unsatisfactory. The authors offer a new and convenient methodology to correct this problem.     

Diazoxide preconditioning attenuates global cerebral ischemia-induced blood-brain barrier permeability

Brain edema formation due to blood-brain barrier (BBB) disruption is a major consequence of cerebral ischemia. Previously, we demonstrated that targeting mitochondrial ATP-sensitive potassium channels (mitoK(ATP)) protects neuronal tissues in vivo and in vitro, however, the effects of mitoK(ATP) openers on cerebral endothelial cells and on BBB functions have never been examined. We investigated the effects of mitoK(ATP) channel opener diazoxide on BBB functions during ischemia/reperfusion injury (I/R). Rats were treated with 6, 20 or 40 mg/kg diazoxide ip for 3 days then exposed to global cerebral ischemia for 30 min. BBB permeability was assessed by administering Evan's-blue (EB) and Na-fluorescein (NaF) at the beginning of the 30 min reperfusion. I/R increased BBB permeability for the large molecular weight EB (ng/mg) in the cortex (control: 146 +/- 12, n = 7; I/R: 1049 +/- 152, n = 11) which was significantly attenuated in diazoxide-treated rats (575 +/- 99, n = 9; 582 +/- 104, n = 8; 20 and 40 mg/kg doses). Diazoxide pretreatment also significantly inhibited the extravasation of the low molecular weight NaF. Edema formation in the cortex was also decreased after diazoxide pretreatment. In cultured cerebral endothelial cells, diazoxide depolarized the mitochondrial membrane, suggesting a direct diazoxide effect on the endothelial mitochondria. Our results demonstrate that preconditioning of cerebral endothelium with diazoxide protects the BBB against ischemic stress.     

Responding to the threat of chronic diseases in India

At the present stage of India's health transition, chronic diseases contribute to an estimated 53% of deaths and 44% of disability-adjusted life-years lost. Cardiovascular diseases and diabetes are highly prevalent in urban areas. Tobacco-related cancers account for a large proportion of all cancers. Tobacco consumption, in diverse smoked and smokeless forms, is common, especially among the poor and rural population segments. Hypertension and dyslipidaemia, although common, are inadequately detected and treated. Demographic and socioeconomic factors are hastening the health transition, with sharp escalation of chronic disease burdens expected over the next 20 years. A national cancer control programme, initiated in 1975, has established 13 registries and increased the capacity for treatment. A comprehensive law for tobacco control was enacted in 2003. An integrated national programme for the prevention and control of cardiovascular diseases and diabetes is under development. There is a need to increase resource allocation, coordinate multisectoral policy interventions, and enhance the engagement of the health system in activities related to chronic disease prevention and control.     

Flat and polypoid adenocarcinomas of the colorectum: A comparative histomorphologic analysis of 47 cases

"Flat" colorectal adenomas and adenocarcinomas are well documented in the Japanese literature but only sporadically reported in the English literature. The present study involved systematic morphological analysis of a large series of colorectal carcinomas (CRCs) to determine the frequency of these "flat" CRCs (FCRCs) and analyze their pathological characteristics and associated patient survival. The study group comprised 47 patients (19 females and 28 males) with primary CRC who underwent colorectal resection at the H. Lee Moffitt Cancer Center between 1997 and 2002. These cases were selected based on the gross appearance of the tumors and after review of all of the hematoxylin and eosin-stained tumor sections in a series of 190 consecutive colorectal resections for CRCs. Application of strict morphological criteria classified 22 tumors as FCRCs. For comparison, 25 "polypoid" CRCs (PCRCs) were also identified. Cases of ulcerative fungating annular CRCs and CRCs with mixed gross appearance were excluded from this analysis. Clinicopathologic data, including patient survival, were compared for FCRCS and PCRCs. Statistical analyses were carried out using the chi(2) or Fisher's exact test and log-rank tests. Overall, 22 of 190 CRCs (11%) were found to meet the morphological criteria of FCRCs. Mean patient age was 70.6 years (range, 55 to 87) for FCRCs versus 68.5 years (range, 54 to 91) for PCRCs, and mean tumor size was 4.7 cm (range, 1.6 to 9) for FCRCs versus 4.4 cm (range, 0.5 to 10) for PCRCs. None of the 22 FCRCs and only 1 of 25 (4%) PCRCs were well differentiated; 17 of 22 (77%) FCRCs and 23 of 25 (92%) PCRCs were moderately differentiated; and 5 of 22 (22%) FCRCs and 1 of 25 (4%) PCRCs were poorly differentiated (P = 0.0087). FCRC cases were staged as 0 stage T1, 3 (14%) stage T2, and 19 (86%) stage T3; PCRC cases, as 4 (16%) stage T1, 14 (56%) stage T2, and 7 (28%) stage 3 (P = 0.000031). Similarly, angiolymphatic invasion was identified in 12 of 22 (54%) FCRCs versus 4 of 25 (16%) PCRCs (P = 0.0123). Although some differences between FCRCs and PCRCs were observed on resection in terms of nodal status (N), presence of metastases (M), and perineural invasion, these differences were not statistically significant. In comparison with PCRCs, FCRCs were associated with significantly shorter postresection patient survival at 1 to 5 years (P = 0.028). We have demonstrated in this report that a proportion of primary CRCs resected at our institution were indeed "flat." Furthermore, these FCRCs exhibited higher histological grades, higher T stage, more frequent angiolymphatic invasion, and shorter patient survival compared with PCRCs. Based on these data, FCRC appears to be a worse subtype of colon cancer than PCRC. Further appraisal of FCRCs and additional studies to further elucidate the molecular mechanisms underlying their morphogenesis are warranted.     

Facial nerve injury induces facilitation of responses in both trigeminal and facial nuclei of rat

A study was made of the effects of facial nerve transection on trigeminal stimulation- evoked field potentials in the principal trigeminal (Pr5) and facial nuclei (7) in rats. Although the transected branch of the facial nerve contains pure motoric efferents, it resulted in enhanced responses in both Pr5 and 7. These electrophysiological results suggest a functional circuitry involving the whiskers, trigeminal nerve, Pr5 and 7 and the facial nerve as efferent. The disconnection (opening) of this loop results in enhanced responsiveness of the neurons in both Pr5 and 7.     

Rapid communication: water disinfection by-products enhanced apoptotic activity in human lymphocytes

The apoptosis-inducing activity of concentrated sediments of disinfected and non-disinfected water samples from the waterworks in Budapest, Hungary, was investigated using cultures of human peripherial blood lymphocytes. Chlorine-treated water and untreated (raw) water sediments were concentrated with the use of Amberlite XAD-2 resin columns. The concentrates were dissolved in dimethyl sulfoxide and added to cultures of human peripherial blood lymphocytes. Apoptotic index was determined in lymphocytes after treatment with the raw or disinfected concentrates by flow cytometry. Disinfected water concentrates of 100 microl/ml increased the apoptotic ratio of lymphocyte culture. The same amount of raw water concentrate also enhanced apoptosis. Both raw water and disinfected water contain substances that induced a significant rate of apoptosis in lymphocyte cultures.