No association between D2 dopamine receptor (DRD2) "A" system alleles, or DRD2 haplotypes, and posttraumatic stress disorder

BACKGROUND

Association studies between marker alleles at the D2 dopamine receptor gene (DRD2) and various psychiatric illnesses have produced conflicting results. Reports of allelic associations were originally made with alcoholism, but were then extended to other psychiatric disorders, including posttraumatic stress disorder (PTSD).

METHODS

We studied allele frequency of the DRD2 TaqI "A," "B," and "D" system markers in 52 European-American subjects with diagnoses of PTSD (based on structured interviews).

RESULTS

Frequency of the A1 allele in this sample was .15, not significantly different from the .19 allele frequency seen in 87 control subjects. We were thus unable to replicate the previous reports of allelic association between the DRD2 TaqI "A1" allele and PTSD. There were also no significant differences in allele frequency for the "B" or "D" systems. We then computed three marker (TaqI "A," "B," and "D" system) haplotypes for the sample; DRD2 haplotype frequencies also did not differ between control subjects and subjects with PTSD.

CONCLUSIONS

We conclude that DRD2 alleles are not associated with PTSD in this sample, and that genetic variation at the DRD2 locus is not likely to be an important contributor to risk for this disorder.

Comparable changes in synaptic dopamine induced by methylphenidate and by cocaine in the baboon brain

Though the blockade of dopamine transporters (DAT) is associated with cocaine's and methylphenidate's reinforcing effects, it is the stimulation of dopamine (DA) receptors, achieved by increases in synaptic DA, that enables these effects to occur. Positron emission tomography (PET) and [11C]raclopride were used to assess the levels of occupancy of DA D2 receptors by dopamine achieved by doses of cocaine or methylphenidate previously documented to block over 70% of DAT. Studies were performed in five baboons using a paired scan protocol designed to measure DA D2 receptor availability (Bmax/Kd) at baseline conditions and after intravenous administration of either cocaine or methylphenidate. Cocaine (1-2 mg/kg) or methylphenidate (0.5 mg/kg) administered 5 min prior to [11C]raclopride decreased Bmax/Kd by 29+/-3% and 32 + 4%, respectively. Smaller reductions in Bmax/Kd (13% for cocaine given 30 min before [11C]raclopride and 25+/-10% for methylphenidate given 40 min before [11C]raclopride) were seen with longer periods between drug and radioligand. These observations are consistent with the slower striatal clearance kinetics of [11C]methylphenidate than [1C]cocaine observed in previous PET experiments and with the approximately twofold higher potency of methylphenidate than cocaine in in vitro experiments. Though the elevation of synaptic DA induced by >70% occupancy of DAT by these drugs lead to a modest increase in occupancy of D2 receptors (25-30%), further studies are required to assess if this is an underestimation because of differences in D2 receptor binding kinetics between raclopride and DA.

The promoter of the plant defensin gene PDF1.2 from Arabidopsis is systemically activated by fungal pathogens and responds to methyl jasmonate but not to salicylic acid

The plant defensin PDF1.2 has previously been shown to accumulate systemically via a salicylic acid-independent pathway in leaves of Arabidopsis upon challenge by fungal pathogens. To further investigate the signalling and transcriptional processes underlying plant defensin induction, a DNA fragment containing 1184 bp and 1232 bp upstream of the transcriptional and translational start sites, respectively, was cloned by inverse PCR. To test for promoter activity this DNA fragment was linked to the beta-glucuronidase (GUS)-encoding region of the UidA gene as a translational fusion and introduced into Arabidopsis ecotype C-24. Challenge of the transgenic plants with the fungal pathogens Alternaria brassicicola and Botrytis cinerea resulted in both local and systemic induction of the reporter gene. Wounding of the transgenic plants had no effect on GUS activity. Treatment of the transgenic plants with either jasmonates or the active oxygen generating compound paraquat strongly induced the reporter gene. In contrast, neither salicylate nor its functional analogues 2,6-dichloroisonicotinic acid and 1,2,3-benzothiodiazole-7-carbothioic acid S-methyl ester resulted in reporter gene induction. These results are consistent with the existence of a salicylic acid-independent signalling pathway, possibly involving jasmonates as regulators, that is triggered by pathogen challenge but not by wounding. The transgenic plants containing the PDF1.2-based promoter-reporter construct will provide useful tools for future genetic dissection of this novel systemic signalling pathway.

Calcium sensors in regulated exocytosis

Neurotransmitter release, hormone secretion and a variety of other secretory process are tightly regulated with exocytotic fusion of secretory vesicles being triggered by a rise in cytosolic Ca2+ concentration. A series of proteins that act as part of a conserved core machinery for vesicle docking and fusion throughout the cell have been identified. In regulated exocytosis this core machinery must be controlled by Ca(2+)-sensor proteins that allow rapid activation of the fusion process following elevation of cytosolic Ca2+ concentration. The properties of such Ca2+ sensors are known from physiological studies but their molecular identity remains to be unequivocally established. The multiple Ca(2+)-dependent steps in the exocytotic pathway suggest the likely involvement of several Ca(2+)-binding proteins with distinct properties. Functional evidence for the role of various Ca(2+)-binding proteins and their possible sites of action is accumulating but a definitive identification of the major Ca(2+)-sensor in the final step of Ca(2+)-triggered membrane fusion in different cell types awaits further analysis.

Acute visual change

Changes in vision or loss of vision are common complaints for patients presenting to the emergency department. Such complaints may represent a simple problem related to recent trauma, early evidence of a systemic disease, or may be a vision-threatening lesion. A logical and organized approach to the history and the physical examination of the patient with eye complaints is key to the diagnosis and treatment of the more significant causes of these complaints. This article reviews an organized approach to the patient with complaint of visual loss and considers the wide differential diagnosis. It focuses specifically on the evaluation of the patient complaining of visual changes resulting from central retinal artery occlusion, central retinal vein occlusion, retinal detachment, acute angle-closure glaucoma, giant cell temporal arteritis, and retrobulbar hemorrhage.

Holism in nursing

This article explores the concept of holism in nursing in terms of what it is and what it has to offer.

Stimulation of NSF ATPase activity during t-SNARE priming

N-Ethylmaleimide-sensitive factor (NSF) plays a key role in vesicular traffic by disassembling and priming SNARE proteins for their function in docking and fusion. We demonstrate that the ATPase activity of NSF is activated by alpha-soluble NSF attachment protein (alpha-SNAP) in a complex with syntaxin 1A. In addition, we show that a construct consisting of the H3 domain of syntaxin IA (GST-synt(195-263), which does not support NSF disassembly in the presence of MgATP gave a larger stimulation. NSF ATPase activation was specific and did not occur using mutant alpha-SNAPs unable to bind GST-synt or with mutated C-termini. We suggest that activation of NSF ATPase activity in the SNARE complex may be essential to allow SNARE priming.

Tumor versus vascular photodamage in a rat tumor model

The [4-(5-nitro-2-furyl)-2-thiazoyl] formamide (FANFT)-induced urothelial tumor in the rat is found to express the mdr gene. The resulting multidrug resistance (MDR) phenotype results in the expression of an outward transport system that prevents cellular accumulation of certain weakly cationic agents. Among the latter is a photosensitizer with known efficacy for the FANFT tumor, the copper benzochlorin iminium salt. FANFT cells are protected from direct cell kill mediated by this drug, suggesting that the substantial delay in tumor regrowth from this tumor/sensitizer combination can be attributed to vascular effects.

Clinical decision support, systems methodology, and telemedicine: their role in the management of chronic disease

In this paper, the design and evaluation of decision support systems, including those incorporating a telematic component, are considered. It is argued that effective design and evaluation are dependent upon the adoption of appropriate methodology set firmly within a systemic framework. Systems modeling is proposed as an approach to system design, with evaluation adopting an approach incorporating evaluability analysis and formative and summative evaluation, including the use of stakeholder matrix analysis. The relevance of such systemic methodology is demonstrated in the context of diabetes and end-stage renal disease as examples of the generic clinical problem of the management of chronic disease.

CNS Adverse Effects of Nonsteroidal Anti-Inflammatory Drugs : Therapeutic Implications

It is difficult to obtain valid estimations of the true incidence of CNS effects associated with nonsteroidal anti-inflammatory drugs (NSAIDs) from spontaneously reported adverse reactions. This is because the reporting rates of adverse reactions are low and the total number of individual drugs prescribed is not generally documented. However, some prospective studies have validated an association between NSAIDs and CNS adverse effects.Aseptic meningitis is the most widely recognised CNS adverse effect associated with NSAIDs. In several case studies, the association has been validated by rechallenge with the NSAID in question. Patients with systemic lupus erythematosus are at an increased risk of NSAID-induced aseptic meningitis, and the meningitis may be a specific cell-mediated immune response.Evidence for an association between NSAIDs and psychiatric adverse effects is mainly anecdotal and comes from spontaneous reports. In some cases, rechallenge with the NSAID strengthens the association. Cognitive dysfunction is also reported, most commonly with indomethacin, with some prospective studies strengthening this association. In contrast, other studies report beneficial CNS effects of NSAIDs, including improvement in short term memory and a protective effect in Alzheimer's disease.In patients presenting with meningitis-like symptoms, NSAID use should be considered as a possible precipitating factor. The possibility of NSAID use as an exacerbating factor in psychiatric and cognitive dysfunction should also be considered, particularly in the elderly.

Analysis of regulated exocytosis in adrenal chromaffin cells: insights into NSF/SNAP/SNARE function

Many of the proteins that function in regulated exocytosis have now been identified. Several proteins form part of a conserved core machinery that acts in many intracellular vesicular fusion steps and their essential roles confirmed by molecular genetic analysis. In addition, studies with adrenal chromaffin and PC12 cells have demonstrated the function of various proteins in regulated exocytosis and have permitted dissection of the stages of exocytosis in which they act. N-Ethylmaleimide-sensitive fusion protein (NSF) and soluble NSF attachment proteins (SNAPs) are key proteins in exocytosis. Examination of their function has indicated that they have a predocking role most likely as molecular chaperones to prepare the docking/fusion machinery. The exact site and time of action in exocytosis of many of the other identified proteins are unknown. A major emphasis for the future will be analysis of the molecular physiology of regulated exocytosis to permit the assignment of functions to identified proteins in particular stages of the regulated exocytotic pathway.

Selective stimulation of the D1 ATPase domain of N-ethylmaleimide-sensitive fusion protein (NSF) by soluble NSF attachment proteins

N-Ethylmaleimide-sensitive fusion protein (NSF) is required for most intracellular membrane fusion events. NSF is recruited to membranes by soluble NSF attachment proteins (SNAPs) and membrane-resident SNAP receptor (SNARE) proteins. The 20 S complex of NSF/SNAPs/SNAREs disassembles when NSF hydrolyses ATP, and this disassembly event is believed to be essential for membrane fusion. SNAPs stimulate NSF ATPase activity, but it is not known which of NSF's two ATPase domains (D1 or D2) is affected. Using recombinant mutant NSFs defective in ATP hydrolysis in one domain only, we found that SNAPs stimulate NSF ATPase activity by a selective action on the D1 domain, yet had no effect on the D2 domain. Since the D1 domain of NSF is implicated in 20 S complex disassembly, this supports the idea that SNAP stimulation of NSF ATPase activity is required for membrane fusion.

Psychosocial factors associated with depression: a study of socially disadvantaged women with young children

This study aims to use valid measures to a) estimate the prevalence of depressive disorder and b) identify psychosocial factors associated with depression in a sample of socially disadvantaged women with children. One hundred ninety-three women, recruited through a doorknock of public housing estates completed an interview that included the Diagnostic Interview Schedule to identify cases of depression and the Mannheim Interview for Social Support. The women also completed self-report questionnaires assessing psychological morbidity, life events, perceptions of intimate relationships, and personality factors. The 6-month prevalence of major depression was 17% and the lifetime prevalence 29%. Major depression was associated with perceptions of low parental care during childhood and low care from current partner, vulnerable personality style, increased reporting of life events, and an unsatisfactory social support network.

Stimulation of NSF ATPase activity by alpha-SNAP is required for SNARE complex disassembly and exocytosis

N-ethylmaleimide-sensitive fusion protein (NSF) and alpha-SNAP play key roles in vesicular traffic through the secretory pathway. In this study, NH2- and COOH-terminal truncation mutants of alpha-SNAP were assayed for ability to bind NSF and stimulate its ATPase activity. Deletion of up to 160 NH2-terminal amino acids had little effect on the ability of alpha-SNAP to stimulate the ATPase activity of NSF. However, deletion of as few as 10 COOH-terminal amino acids resulted in a marked decrease. Both NH2-terminal (1-160) and COOH-terminal (160-295) fragments of alpha-SNAP were able to bind to NSF, suggesting that alpha-SNAP contains distinct NH2- and COOH-terminal binding sites for NSF. Sequence alignment of known SNAPs revealed only leucine 294 to be conserved in the final 10 amino acids of alpha-SNAP. Mutation of leucine 294 to alanine (alpha-SNAP(L294A)) resulted in a decrease in the ability to stimulate NSF ATPase activity but had no effect on the ability of this mutant to bind NSF. alpha-SNAP (1-285) and alpha-SNAP (L294A) were unable to stimulate Ca2+-dependent exocytosis in permeabilized chromaffin cells. In addition, alpha-SNAP (1-285), and alpha-SNAP (L294A) were able to inhibit the stimulation of exocytosis by exogenous alpha-SNAP. alpha-SNAP, alpha-SNAP (1-285), and alpha-SNAP (L294A) were all able to become incorporated into a 20S complex and recruit NSF. In the presence of MgATP, alpha-SNAP (1-285) and alpha-SNAP (L294A) were unable to fully disassemble the 20S complex and did not allow vesicle-associated membrane protein dissociation to any greater level than seen in control incubations. These findings imply that alpha-SNAP stimulation of NSF ATPase activity may be required for 20S complex disassembly and for the alpha-SNAP stimulation of exocytosis.

Prevalence of Q fever in a rural practice

BACKGROUND

Q fever is a world-wide condition caused by the rickettsia Coxiella burnetii. It appears more prevalent in agrarian communities and may have serious sequelae.

METHODS

A descriptive, cross-sectional, observational study using a randomly selected group of the adult working practice population in a rural practice in West Wales was devised. An immunofluorescence test, which identified past infection, was used to look for associations between C. burnetii seropositivity and farm-related or social activities, and to compare the findings with those of other studies. An attempt was made to establish a clinical profile for the illness Q fever.

RESULTS

Twenty-one subjects were found to be seropositive to C. burnetii. No definite consistent clinical features were identified. Farming was undoubtedly a risk factor for the disease, maybe with other related factors also important. There was a possibility that alcohol had a protective effect. No sinister sequelae were described.

CONCLUSIONS

Q fever occurs more frequently in farmers than in non-farmers, but was less common than previously thought. Is Q fever accurately described in medical textbooks? A case is made for a more co-operative approach between primary carers and epidemiologists in the study of illnesses in populations.

Foscarnet for prevention of cytomegalovirus infection in allogeneic marrow transplant recipients unable to receive ganciclovir

Cytomegalovirus (CMV) disease can be prevented by administration of ganciclovir prophylactically post-transplant. However, up to 30% of patients discontinue use of ganciclovir as a result of profound neutropenia and may subsequently develop CMV infections while unprotected. To prevent reactivation of CMV, we administered foscarnet to 39 adults unable to receive ganciclovir due to delayed engraftment or ganciclovir-induced neutropenia. Twenty-four (62%) of the patients had received T cell-depleted marrow transplants. Foscarnet sodium 60 mg/kg i.v. daily was continued until the neutropenia resolved, at which time ganciclovir was resumed. CMV prophylaxis commenced at a median of 28 days following transplantation. Median time to initiation of foscarnet was day 60 post-transplant, and the median duration of treatment was 22 days. Foscarnet was well-tolerated. Six (15%) patients had CMV detected while receiving prophylaxis, and CMV-related mortality was 5%. Foscarnet is a safe and effective agent for prevention of CMV disease in allogeneic transplant recipients unable to receive ganciclovir.

Histologic correlation of image-guided core biopsy with excisional biopsy of nonpalpable breast lesions

OBJECTIVE

To examine the histologic correlation between image-guided large-core needle biopsy (LCNB) and excisional biopsy of nonpalpable breast lesions.

DESIGN

Histologic findings of LCNB and excision specimens were reviewed for patients who underwent image-guided LCNB of nonpalpable breast lesions from April 1, 1993, to March 31, 1996. Histologic diagnosis of the excision specimen was used as a criterion standard. Follow-up ranged from 1 to 4 years.

SETTINGS

A dedicated breast imaging clinic on the campus of an urban community hospital.

PATIENTS

Five hundred fifty-two patients with nonpalpable mammographically detected abnormalities.

MAIN OUTCOME MEASURES

Histologic diagnoses of LCNB and excision specimens (part of a prospectively designed, ongoing quality audit process).

RESULTS

Histologic findings were benign in 389 LCNB specimens (70.5%) and abnormal in 163 (29.5%). The benign LCNB specimens remained benign on clinical and radiologic follow-up, with 1 missed malignant diagnosis. One hundred seventy-three patients underwent excision following LCNB, resulting in 10 benign and 163 abnormal specimens. Diagnoses of 102 LCNB specimens showing invasive cancer were confirmed on excision. Of 54 patients in whom LCNB specimens showed ductal carcinoma in situ (DCIS), 10 showed DCIS plus invasive cancer on excision. Of 6 patients in whom LCNB specimens showed atypical duct hyperplasia (ADH), 1 was benign, 1 showed ADH and invasive cancer, 3 showed ADH and DCIS, and 1 remained ADH exclusively on excision. The histologic diagnosis for 10 benign LCNBs remained benign after excision. Correlation coefficient was 0.93 (P < .001).

CONCLUSIONS

Benign disease and invasive cancer of the breast can be diagnosed with a high level of confidence using image-guided LCNB. The histologic diagnosis for patients whose LCNB specimens show ADH or DCIS may change after excision.

Acid leaching studies of neutron-irradiated chyrsotile asbestos

Samples of chrysotile from Quebec (UICC B and Jeffrey 4T-30) and from the Coalinga region of California (Calidria RG-144) were irradiated with thermal neutrons in a reactor. The main activation products induced were 46Sc, 51Cr, 59Fe and 60Co. Accurately weighed samples of the irradiated materials were dispersed in N HCl by hand shaking for 10 s. After leaching for predetermined periods at 25 degrees C, the samples were filtered and the concentrations of Mg determined in the filtrates by inductively-coupled plasma atomic emission spectrometry (IPC-AES) and the activities of the four radionuclides by high resolution gamma-ray spectrometry. Similar measurements were made on solutions obtained by refluxing samples of irradiated chrysotile with 2N HCl for 2 h. The specific activities of each of the four activation products were calculated in arbitrary units and, as the concentrations of Sc, Cr, Fe and Co in the UICC B sample had already been determined, it was possible to estimate the concentrations of these elements in the other two samples. Similarities in the leaching patterns of magnesium and of the activation products showed that with all samples, high proportions of the parent trace elements were present in the form of isomorphous substitutes for magnesium in structural brucite. Agreement was closest with the Calidria chrysotile in which all the radionuclides had a similar pattern. With the Jeffrey and UICC B samples, the presence of a high proportion of the iron as relatively insoluble magnetite accounted for the observed discrepancy in behaviour between 59Fe and Mg. More detailed calculation of leaching rates over specific time intervals showed that, initially, 51Cr and 60Co dissolved more rapidly than Mg but that this was followed by a period in which the opposite was the case. It was concluded that the Calidria RG-144 sample is an ideal candidate for studies of magnesium dissolution in vivo.