Influence of TNFalpha and LTalpha single nucleotide polymorphisms on susceptibility to and prognosis in cutaneous malignant melanoma in the British population.

Cutaneous malignant melanoma (CMM) is a potentially fatal malignancy in which exposure to UV light is the most important risk factor. Several lines of evidence suggest that increased expression of tumour necrosis factor (TNF) alpha, upregulated by UV exposure, may contribute to tumour escape from the immune response. In this study, we addressed whether single nucleotide polymorphisms (SNPs) in the TNFalpha promoter and lymphotoxin (LT) alpha gene are associated with susceptibility to or known prognostic indicators (e.g. initial tumour growth phase, Breslow thickness, mitotic count in vertical growth phase tumours, and tumour regression) in CMM. One hundred and forty-six British Caucasian CMM patients and 220 controls were typed for TNFalpha-376, -308 and -238 and LTalpha+252 SNPs by ARMS-PCR. Only the TNFalpha -238 GG (P = 0.05) and GA (P = 0.03) genotypes showed slight, but significant, associations with CMM, while LTalpha+252 AA was associated with a higher mitotic count in vertical growth phase tumours (P = 0.02). Both TNFalpha-238 and LTalpha+252 SNPs showed linkage disequilibrium with HLA-DQB1*0303 and *0301 alleles, variably implicated in CMM susceptibility/prognosis. In addition, TNFalpha-238, -308, LTalpha+252 haplotypes were assigned and compared. The GGA haplotype showed a modest association with CMM (P = 0.04) and with stage of disease (P = 0.03) and initial growth phase in CMM (P = 0.02), but these associations were only significant when P-values were uncorrected. Unlike basal cell carcinoma, these preliminary findings suggest that genetic variation associated with differential TNFalpha and LTalpha production is unlikely to play a major, independent role in susceptibility to, and perhaps prognosis in, CMM.     

Atypical hemolytic uremic syndrome in human immunodeficiency virus-1-infected children

We describe the clinical and pathological findings of the hemolytic uremic syndrome (HUS) in two children with human immunodeficiency virus (HIV) infection. Both patients presented with microangiopathic hemolytic anemia, thrombocytopenia, and subsequently developed renal failure. The diagnosis of HUS was confirmed by renal histopathology in both patients. None of these children presented with bloody diarrhea, evidence of circulating antibody response to Escherichia coli O157 lipopolysaccharide, or other known risk factors for HUS, except for the presence of HIV infection. Each patient was treated with intravenous plasma infusion and renal replacement therapy. Their clinical course was characterized by non-oliguria and lack of significant hypertension throughout the acute phase of the disease. Despite these favorable clinical parameters, both patients developed end-stage renal failure. The etiology of this atypical HUS characterized by poor renal survival remains unknown and the role of HIV infection in its pathogenesis, although possible, is unclear. Received March 5, 1996; received in revised form and accepted October 15, 1996     

Objective morphological assessment of macular hole surgery by scanning laser tomography

AIM—To assess the morphological change in retinal topography using a scanning laser tomographer following macular hole surgery. To compare the results of scanning laser tomography with clinical evaluation and visual function assessment.
METHODS—The sample for this pilot study comprised four eyes exhibiting different stages of macular hole formation preoperatively. Subjects were assessed preoperatively and at 1 and 3 months postoperatively. Each assessment included visual acuity, letter contrast sensitivity, clinical examination (including automated static perimetry), and scanning laser tomography. The Heidelberg retina tomograph (HRT) was used to acquire digitised scanning laser tomography images of the macula (10° and 20° fields). Surgery essentially comprised vitrectomy, peeling of the posterior hyaloid face, if still attached, and intraocular gas tamponade. The magnitude and significance of topographic change were determined postoperatively using the HRT topographic difference facility.
RESULTS—Topographic difference analysis of the right and left eyes of case 1 showed a significant reduction in the height of the retina postoperatively. Topographic difference analysis of case 2 showed no significant change in topography. Topographic difference analysis of case 3 showed a significant increase in the height of the retina postoperatively. Scanning laser tomography agreed with clinical assessment based upon fundus biomicroscopy in three of the four eyes studied; the postoperative closure of the stage 2 macular hole (as noted by clinical assessment) proved to be too small to reach statistical significance. Scanning laser tomography agreed with the assessment of visual function in two eyes; the agreement between scanning laser tomography and visual function depends, in part, on the stage of development of the macular hole.
CONCLUSION—Scanning laser tomography provides an objective evaluation of the outcome of macular hole surgery. Studies employing larger sample sizes are required to fully determine the clinical worth of the technique.

     

Development of a human cell line by selection and drug-metabolizing gene transfection with increased capacity to activate promutagens

We have isolated a human lymphoblastoid cell line with higher levels of native cytochrome P450IA1 activity and by DNA transfection introduced human cDNAs for a putative cytochrome P450IIA2 and epoxide hydrolase (E.C. 3.3.2.3). The resultant cell line, designated MCL-1, was substantially more sensitive to the mutagenicity of dimethylnitrosamine and benzo[a]pyrene than the AHH-1 cell line and was found to have increased metabolism of benzo[a]pyrene to dihydrodiols. The increase in native cytochrome P450IA1 activity was achieved by mutation and selection based on resistance to the phototoxicity of benzo[ghi]perylene. One resistant clone, designated L3, was used for subsequent studies. Two complete cDNAs, one encoding a putative cytochrome P450IIA2 and the other a microsomal epoxide hydrolase, were isolated from a human liver cDNA library. After introduction of the cDNAs into an expression vector and transfection into AHH-1 cells, gene expression was detected at the level of enzyme activity (epoxide hydrolase) or by increased sensitivity to dimethylnitrosamine cytotoxicity/mutagenicity (putative P450IIA2). A vector containing both cDNAs was then constructed and transfected into L3 cells to produce MCL-1 cells. The potential usefulness of drug-metabolizing gene transfection and of the MCL-1 cell line, in particular, for genetic toxicity testing is discussed.     

Retinal pigment epithelial change and partial lipodystrophy

Cuticular drusen and retinal pigment epithelial changes were found incidentally in a 27 year old Lebanese woman during assessment of partial lipodystrophy. Her vision was normal despite involvement of both maculae. The patient had hypocomplementaemia, but serum C3 nephritic factor was absent and renal function was normal. She had impaired glucose tolerance and a continuous infusion of glucose with model assessment (CIGMA) test revealed low normal tissue insulin sensitivity and high normal pancreatic beta cell function. Mild fasting hypertriglyceridaemia (2.0 mmol/l) may have been secondary to impaired insulin sensitivity. Endocrine function was otherwise normal apart from a completely absent growth hormone response to adequate hypoglycaemia. The simultaneous occurrence of partial lipodystrophy and retinal pigmentary epithelial and basement membrane changes appears to be a newly recognized syndrome.     

Forensic psychiatrists' and psychologists' understanding of insanity: misguided expertise?

The ability of mental health experts to consult on insanity cases is highly dependent on their accurate understanding of the current Canadian standard. The study surveyed experienced forensic psychiatrists and psychologists and found the majority (88%) had erroneous beliefs regarding the insanity standard. Results of a discriminant analysis suggest that experience with insanity evaluations and courtroom testimony may improve experts' understanding. Implications of these results are discussed with respect to professional training and public policy.     

LONG-TERM OUABAIN ADMINISTRATION DOES NOT ALTER BLOOD PRESSURE IN CONSCIOUS SPRAGUE-DAWLEY RATS

1. We tested the ability of ouabain to cause chronic hyper tension by continuously infusing ouabain for 28 days (mini-osmotic pump implantation; i.p.). The blood pressure and metabolic effects of sham (150 mmol/L NaCI; n= 12) or ouabain infusion (10 μg/kg per day; n= 14; 100 μg/kg per day; n = 14) were examined in conscious Sprague-Dawley rats. 2. Plasma ouabain concentrations measured after 28 days of ouabain infusion were as follows: sham, not detectable (n= 11); ouabain 10 μg/kg per day, 0.60 ± 0.07 nmol/L (n= 14); and ouabain 100 μg/kg per day, 7.17 ± 0.57 nmol/L (n= 14; P < 0.001). 3. Sham or ouabain infusion did not alter food intake, bodyweight, water intake or urine output in conscious rats. 4. Blood pressure was not altered by sham treatment. Ouabain at 10 μg/kg per day or 100 μg/kg per day did not produce consistent rises in blood pressure. Ouabain at 10 μg/kg per day increased blood pressure on treatment day 12 only (+ 6mmHg; P < 0.05), while at 100μg/kg per day blood pres sure increased on treatment days 16 (+ 9 mmHg; P < 0.05) and day 18 (+ 8mmHg; P < 0.05) only. There was no significant difference in blood pressure between sham and ouabain groups. 5. Renal blood flow was decreased in rats infused with ouabain at 10 μg/kg per day (2.0 ± 0.3 mL/min per 100 g body-weight; n= 5; P < 0.01) and 100 μg/kg per day (2.2 ± 0.4 mL/ min per 100 g bodyweight; n= 7; P < 0.05) compared with sham treatment (3.5 ± 0.2 mL/min per 100 g bodyweight; n= 6). Renal vascular resistance was increased in rats treated with ouabain at 10 μg/kg per day (65.5 ± 12.6 mmHg/mL per min per 100 g bodyweight; n= 5; P < 0.01) and 100 μg/kg per day (66.0 ± 15.6 mmHg/mL per min per 100 g bodyweight; n= 7; P < 0.05) compared with sham treatment (32.6 ± 2.5 mmHg/mL per min per 100 g bodyweight; n= 6). 6. High plasma concentrations of ouabain do not cause consistent increases in blood pressure in conscious Sprague-Dawley rats.     

Prenatal and adult presymptomatic testing for Huntington's disease

The discovery of a fragment of DNA that is linked closely to the Huntington's-disease autosomal locus offers the opportunity for the presymptomatic diagnosis of this dominantly-inherited neurodegenerative disorder. Presymptomatic testing will present individuals and society with difficult choices and responsibilities. A pilot adult presymptomatic test programme is under way for SA families. Presymptomatic testing requires intensive counselling both before and after the test. A form of prenatal test, which is applicable to a significant proportion of couples with one partner at risk of Huntington's disease, is available also. As this form of prenatal test does not change the risk status of the parent, less extensive counselling is required and testing is available nationally through the SA programme. It is anticipated that other states will develop their own diagnostic programmes in the near future. This article explains the basis for the test, its accuracy and the importance of obtaining DNA from key individuals in pedigrees of Huntington's disease.