[Cloning of genes transactivated by nonstructural protein 4A of hepatitis C virus.]

BACKGROUND

To construct a subtractive cDNA library of genes transactivated by NS4A protein of hepatitis C virus with suppression subtractive hybridization technique (SSH).

METHODS

The mRNA was isolated from Hep G2 cells transfected pcDNA3.1(-)-NS4A and pcDNA3.1(-) empty vector, respectively, then the cDNA was synthesized. SSH method was employed to analyze the differentially expressed RNA sequence between the two groups. The twice enriched PCR products were subcloned into T/A vectors to set up the subtractive library. Amplification of the library was carried out with E.coli strain JM109. The cDNA was sequenced and analyzed in comparison with those in GenBank with Blast search after PCR.

RESULTS

The amplified library contained 36 positive clones. Colony PCR showed that 36 clones contained 200-1000 bp inserts. Sequence analysis was performed in 25 clones, and the full length sequences were obtained with bioinformatics method. Altogether 20 kinds of coding sequences were achieved, which consisted of 18 kinds of known and 2 kinds of unknown ones. The obtained sequences may be target genes transactivated by NS4A protein of HCV, among which some genes coding for proteins involved in cell cycle regulation, cell apoptosis, signal transduction pathway and tumour development.

CONCLUSION

A subtractive library of genes transactivated by NS4A protein of HCV was constructed successfully, which brought some new clues for studying the biological functions and pathogenesis of the viral proteins.

Prevalence of mitochondrial DNA haplogroups in an Australian population

Mitochondrial DNA (mtDNA) haplogroups are 'neutral polymorphisms' in the mtDNA genome, which have accumulated and persisted along maternal lineages as the human population has migrated worldwide. Three ethnically distinct lineages of human mtDNA populations have been identified: European, characterized by nine haplogroups H, I, J, K, T, U, V, W and X; African, characterized by superhaplogroup L and Asian, characterized by superhaplogroup M. We studied the prevalence of mtDNA haplogroups in participants of the Blue Mountains Eye Study, a large population-based survey of vision conducted between 1991 and 2000 of non-institutionalized permanent residents aged 49 years or older from two suburban postcode areas, west of Sydney, Australia. Total DNA isolated from either hair follicles or blood was available for 3377 of the 3509 participants (96.2%) to determine mtDNA haplogroups by polymerase chain reaction/restriction fragment length polymorphism analysis. Approximately 94.2% of samples could be assigned to one of the nine major European haplogroups, whereas a further 1.2% included the African (L) and Asian (M) superhaplogroups. The five principal haplogroups represented were H (42.9%), U (14.1%), J (10.7%), T (9.2%) and K (8.1%), which together included 85% of this population.

Retinal vascular calibre and the risk of coronary heart disease-related death

OBJECTIVE

To examine whether retinal vascular calibre independently predicts risk of coronary heart disease (CHD) -related death.

METHODS

In a population-based cohort study of 3654 Australians aged > or = 49 years, retinal arteriolar and venular calibres were measured from baseline retinal photographs and the arteriole to venule ratio (AVR) was calculated. CHD-related death was confirmed from the Australian National Death Index.

RESULTS

Over nine years, 78 women (4.1%) and 114 men (7.8%) had incident CHD-related deaths. In people aged 49-75 years, wider venules were associated with CHD death, with relative risk (RR) 1.8 (95% confidence interval (CI) 1.1 to 2.7) and RR 2.0 (95% CI 1.1 to 3.6) per standard deviation (SD) increase in venular calibre for men and women, respectively, after adjustment for traditional risk factors. Additionally, in women aged 49-75 years, smaller AVR and narrower arterioles were associated with CHD death (RR 1.5, 95% CI 1.1 to 2.2, and RR 1.9, 95% CI 1.0 to 3.5 per SD decrease in AVR and arteriolar calibre, respectively, after adjustment). These associations were not observed in people aged > 75 years.

CONCLUSIONS

These findings suggest that microvascular disease processes may have a role in CHD development in middle-aged people, particularly in women. Retinal photography may be useful in cardiovascular risk prediction.

Thermal desorption of hydrogen from carbon nanosheets

Carbon nanosheets are a unique nanostructure that, at their thinnest configuration, approach a single freestanding graphene sheet. Temperature desorption spectroscopy (TDS) has shown that the hydrogen adsorption and incorporation during growth of the nanosheets by radio frequency plasma-enhanced chemical vapor deposition are significant. A numerical peak fitting to the desorption spectra (300-1273 K) via the Polanyi-Wigner equation showed that desorption followed a second order process, presumably by the Langmuir-Hinshelwood mechanism. Six peaks provide the best fit to the TDS spectra. Surface desorption activation energies were determined to be 0.59, 0.63, and 0.65 eV for the external graphite surface layers and 0.85, 1.15, and 1.73 eV for desorption and diffusion from the bulk. In contrast to TDS data from previously studied a-C:H films [Schenk et al. J. Appl. Phys. 77, 2462 (1995)], a greater amount of hydrogen bound as sp(2) hybridized carbon was observed. A previous x-ray diffraction study of these films has shown a significant graphitic character with a crystallite dimension of L(a)=10.7 nm. This result is consistent with experimental results by Raman spectroscopy that show as-grown carbon nanosheets to be crystalline as commercial graphite with a crystallite size of L(a)=11 nm. Following TDS, Raman data indicate that the average crystallite increased in size to L(a)=15 nm.

Effects of mechanical pressure on intracellular calcium release channel and cytoskeletal structure in rabbit mandibular condylar chondrocytes

Many signal molecules are involved in mechanotransduction process, among which intracellular calcium and cytoskeleton are two of the most important ones. This study investigated the changes of intracellular calcium and cytoskeleton under pressure and the effects of intracellular calcium variation on cytoskeleton responses to the pressure in rabbit mandibular condylar chondrocytes (MCCs). In vitro cultured MCCs from 2-week-old New Zealand rabbits were incubated for observation of intracellular calcium variation under laser scanning microscope. Coomassie BB staining was used to observe the characteristics of cytoskeleton. We found that intracellular calcium increased following the irritation by 1,25(OH)2D3, whereas it remained unchanged when inositol triphosphate receptor (IP3R) channel was blocked by heparin. Pretreatment with pressure of 90 kPa for 60 min enhanced the sensitivity of IP3R channel and caused higher intracellular calcium concentration. The cytoskeletons of MCCs were revealed correspondingly uniform and reticular in the control, most of which showed higher expression in tighter arrangement under continuous pressure of 90 kPa for 60 min but lower expression when the pressure time was prolonged to 360 min. When MCCs were pretreated with heparin, the cytoskeleton of them displayed sparsely and discontinuously under 90 kPa for 60 min. To sum up, both cytoskeleton and intracellular calcium participate in the transition process of mechanical signal to biological effects of MCC. However, the decrease of intracellular calcium resulted from IP3R channel blocking obviously interferes the recomposition of cytoskeleton under mechanical pressure, which suggests that calcium message is indispensable to the cytoskeleton response of MCC under pressure.

Retinal microvascular signs and risk of stroke and stroke mortality

OBJECTIVE

The purpose of this study was to assess the relation of retinal microvascular signs and incident stroke and stroke mortality in an older population.

METHODS

The authors took retinal photographs on baseline participants (3,654 patients aged 49+ years) of the Blue Mountains Eye Study (1992 to 1994). They assessed the presence of retinopathy (microaneurysms, retinal hemorrhages) in participants without diabetes and retinal arteriolar signs in all participants using standardized grading protocols. Incident stroke/TIA/cerebrovascular death (combined stroke events) were identified at follow-up examinations during 1997 to 1999.

RESULTS

During a 7-year period, 859 participants died, 97 (11.3%) of which died of cerebrovascular causes. Of survivors, 24 had confirmed incident stroke, and 11 had incident TIA. Combined stroke events were more frequent in participants with retinopathy (5.7%), with moderate/severe arteriovenous nicking (4.2%), or with focal arteriolar narrowing (7.2%) compared with those without (1.9%). After controlling for age, sex, systolic blood pressure, smoking, and self-rated health, retinopathy was significantly associated with combined stroke events (relative risk [RR] 1.7, 95% CI 1.0 to 2.8) in persons without diabetes. This association was stronger in those without severe hypertension (RR 2.7, CI 1.2 to 6.2) or in persons with two or more retinal microvascular signs (RR 2.7, CI 1.5 to 5.2). Generalized or focal arteriolar narrowing or arteriovenous nicking was not independently associated with combined stroke events after multivariate adjustment.

CONCLUSIONS

In older Australians without diabetes, retinopathy signs predict stroke or stroke-related death independent of traditional stroke risk factors.

Early age-related maculopathy in eyes after cataract surgery

PURPOSE

To assess age-related maculopathy (ARM) in eyes of patients who had undergone cataract surgery for at least a year.

METHODS

Consecutive patients aged 60+ years who had undergone cataract surgery at Westmead Hospital, Sydney, Australia, during 2001-2003 were examined in 2004. Interview using standardized questionnaires and stereo retinal photography was performed. Retinal photographs were graded using the Wisconsin ARM grading system. The proportions with ARM were compared between surgical and nonsurgical eyes, and between this surgical cohort and the Blue Mountains Eye Study (BMES) population.

RESULTS

Of the 622 eligible patients, 454 (73%) were re-examined, with a mean follow-period of 2.8 years. Surgical eyes had a higher proportion of early ARM compared to nonsurgical eyes (15.2 vs10.3%, P=0.07) and to the early ARM prevalence found in BMES participants of similar age (14.5 vs6.9%, P<0.01), which persisted after age standardization to the BMES population (9.7 vs6.9%, P<0.05).

CONCLUSIONS

We found an increased prevalence of early ARM in surgical eyes of patients 1-3 years after cataract surgery. Whether this increased early ARM prevalence leads to an increased prevalence of late ARM in the long-term warrants further investigation.

Dyslipidaemia and microvascular disease in the retina

PURPOSE

There are few data on the effect of serum lipids on microvascular disease. This study assessed the relationships between serum lipid levels and microvascular disease, as seen in the retina, among participants who attended a population-based study in Australia (n=3654, aged 49+years).

METHODS

Diameters of retinal arterioles and venules were measured from digitised photographs of each participant to obtain an estimate of generalised arteriolar narrowing. Focal arteriolar narrowing, arteriovenous nicking, and retinopathy lesions (microaneurysms, haemorrhages, hard/soft exudates) were graded using a standard protocol. Fasting blood tests were performed in 89% of subjects. Adjusted means were calculated using general linear models. Logistic regression models were used to determine the odds ratios for retinal microvascular signs.

RESULTS

After controlling for age, sex, body mass index, smoking, and mean arterial blood pressure, elevated high-density lipoprotein cholesterol was associated with narrower retinal arterioles (Ptrend=0.002) and venules (Ptrend=0.03) and with increased odds of generalised arteriolar narrowing (odds ratio 1.6, 95% confidence interval 1.1-2.2 for the highest vs the lowest quintile of high-density lipoprotein cholesterol). Serum triglyceride had a U-shaped relationship with venular diameter (Ptrend=0.003). We found no consistent pattern of association between serum total cholesterol or low-density lipoprotein cholesterol and any retinal microvascular signs.

CONCLUSIONS

These findings suggest that microvascular disease in the retina may result from processes distinct from dyslipidaemia.

Age-related maculopathy and cataract surgery outcomes: visual acuity and health-related quality of life

PURPOSE

To assess visual acuity (VA) and health-related quality of life (HRQoL) outcomes in patients with and without age-related maculopathy (ARM) after cataract surgery.

METHODS

Patients aged 60+ years who had undergone cataract surgery at the Westmead Hospital during 2001-2003 were re-examined 1-3 years after surgery. Tests included VA and assessment of visual- and HRQoL using standardised questionnaires (VF-14, SF-12). Preoperative comorbidity data were collected from medical records. Poor surgical outcomes (VA<6/12; no VA improvement; lowest quintile of VF-14, SF-12 scores) were compared in patients with and without ARM, adjusting for age, sex, preoperative systemic comorbidities, ocular comorbidities and surgical or postoperative complications.

RESULTS

Of 622 surviving patients, 454 (73%) were followed up for a mean period of 2.8 years. Similar proportions with VA>or=6/12 were observed in patients with (80.2%) and without (88.8%) pre-existing ARM. Preoperative early ARM was only associated with slightly lower mean VF-14 scores (87.64 with vs 92.58 without ARM, P=0.01). Increasing age and preoperative ocular comorbidities were associated with all poor outcomes measured. Low SF-12 scores were associated with preoperative systemic comorbidities.

CONCLUSION

Our study documents favourable cataract surgical outcomes 1-3 years after cataract surgery in patients with preoperative ARM.

The spectrum of vibration modes in soft opals

Numerous vibrational modes of spherical submicrometer particles in fabricated soft opals are experimentally detected by Brillouin light scattering and theoretically identified by their spherical harmonics by means of single-phonon scattering-cross-section calculations. The particle size polydispersity is reflected in the line shape of the low-frequency modes, whereas lattice vibrations are probably responsible for the observed overdamped transverse mode.

Five-year incidence and progression of vascular retinopathy in persons without diabetes: the Blue Mountains Eye Study

PURPOSE

To assess the 5-year incidence of vascular retinopathy and its associations in an older nondiabetic population.

METHODS

The Blue Mountains Eye Study examined 3654 residents aged 49+ years (82.4% response rate) during 1992-1994, and re-examined 2335 (75.1% of survivors) during 1997-1999. Retinopathy lesions (microaneurysms, haemorrhages, hard or soft exudates) were assessed from 6-field retinal photographs in persons without diabetes. Incident retinopathy was assessed in those at risk. Hypertensive status was defined following the WHO/International Society of Hypertension guidelines.

RESULTS

Of the 2335 re-examined, 195 had retinopathy lesions at baseline and 1725 were at risk of retinopathy after excluding subjects with diabetes (n=261), retinal vein occlusion (n=52) or missing/un-gradable photographs (n=102). The cumulative 5-year incidence was 9.7% (95% confidence intervals (CI) 8.3-11.1%). Age was the only factor significantly associated with incident retinopathy (Pfor trend=0.012). Neither fasting blood glucose (age-sex-adjusted P=0.147) nor hypertension (adjusted Pfor trend=0.43) was associated with incident retinopathy. Of the 195 with retinopathy lesions at baseline, 3.5% developed diabetes, 13.3% progressed, and 72.3% regressed/disappeared over 5 years. Progression was positively associated with elevated blood pressure (BP) (adjusted odds ratio (OR) 1.3, 95% CI 1.1-1.6 per 10 mmHg systolic BP) and inversely associated with fasting glucose level (OR 0.36, CI 0.14-0.92 per mmol/l increase). Aspirin use was weakly associated with regression (OR 2.4, CI 1.0-6.0).

CONCLUSIONS

Over 5 years, retinopathy developed in 10% of older people without diabetes, while 72% of baseline lesions regressed. Age was significantly associated with the development of these lesions.

Versazyme supplementation of broiler diets improves market growth performance

Day-old male broiler chicks were randomly assigned to 32 floor pens in a completely randomized block design and grown to 6 wk of age. Birds in experiment 1 were fed 1 of 2 basal diets supplemented with or without a protease containing feed additive, Versazyme (VZ). The 4 treatments were 1) control (C), a corn-soybean meal diet that contained 95% of amino acids recommended by NRC except for threonine and isoleucine; 2) C + 0.1% VZ (wt/wt) (C+) in the starter diet only; 3) high (HP) amino acid diet, a corn-soybean meal diet with 100 to 105% of amino acid recommended by NRC except for threonine and isoleucine; and 4) HP + 0.1% VZ (wt/wt) (HP+) in starter diet only. Supplementing both diets with VZ improved BW and feed conversion ratio (FCR) at 21 d of age and BW at 42 d of age. Cumulative 42-d FCR was only improved in birds fed the HP+ diet. Birds in experiment 2 received the following treatments: 1) HP, 2) HP + 0.1% VZ batch A (wt/wt) (A) in starter diet only, and 3) HP + 0.1% VZ batch B (wt/wt) (B) in starter diet only. Enzyme supplementation improved 22-d BW and FCR. There was no significant difference in BW at 43 d of age. Both A and B improved overall FCR (1.758 and 1.751 vs. 1.79 for A and B vs. HP, respectively). In conclusion, supplementation of starter broiler diets with VZ resulted in improved market growth performance.

Effects of 1, 6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl]diamantane (DPD), a reactive oxygen species and apoptosis inducing agent, on human leukemia cells in vitro and in vivo

1, 6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl]diamantine (DPD), a new cytostatic and differentiation inducing agent, was found to inhibit the growth of several cancer cell lines in the National Cancer Institute (NCI) Anticancer Drug Screen system. Previously, we demonstrated that DPD inhibited the growth of human colon cancer cell lines both in vitro and in vivo. In this study, we examined the anticancer effects of DPD on two human leukemia cells lines. DPD exerted growth inhibitory activities in vitro against two human leukemia cell lines, the promyeloid line HL-60 and the lymphoblastic line Molt-3. The in vivo effect of tumor growth suppression by DPD was also observed in mouse xenografts. No acute toxicity was observed after an intra-peritoneal challenge of DPD in "severe combined immune-deficiency" (SCID) mice twice a week. The in vitro study showed HL-60 was more sensitive to DPD than Molt-3 through induction of G(0)/G(1) cell-cycle arrest with the appearance of a hypodiploid DNA fraction. The increased superoxide (O(2)(-)), dissipation of the mitochondrial membrane potential, activation of caspase 3, and increase in annexin V binding were evident before apoptosis in DPD-treated cells. The superoxide dismutase 1 (SOD1) mRNA expression was also decreased in DPD-treated HL-60 and Molt-3 cells. Thus, it appeared that inhibition of SOD might be the major cause for the production of cellular superoxide with concomitant decrease of H(2)O(2) in DPD-treated cells. Addition of antioxidant can reduce DPD-induced mitochondrial damage, caspase activation, and annexin V binding in HL-60 cells. The results suggest that the cellular generation of O(2)(-) plays a role in initiating and coordinating DPD-mediated growth arrest and apoptosis of HL-60 cells. Importantly, addition of arsenic trioxide, a compound capable of reactive oxygen species (ROS) generation, significantly enhanced the in vitro activity of DPD. These results suggest that DPD appears to be a potential new modality in human leukemia therapy.

Limits for the central production of Theta+ and Xi(--)pentaquarks in 920-GeV pA collisions

We have searched for Theta+(1540) and Xi(--)(1862) pentaquark candidates in proton-induced reactions on C, Ti, and W targets at midrapidity and square root of s = 41.6 GeV. In 2 x 10(8) inelastic events we find no evidence for narrow (sigma approximately 5 MeV) signals in the Theta+ --> pK0(S) and Xi(--) --> Xi- pi- channels; our 95% C.L. upper limits (UL) for the inclusive production cross section times branching fraction B dsigma/dy/(y approximately 0) are (4-16) mub/N for a Theta+ mass between 1521 and 1555 MeV, and 2.5 mub/N for the Xi(--). The UL of the yield ratio of Theta+/Lambda(1520) < (3-12)% is significantly lower than model predictions. Our UL of B Xi(--)/Xi(1530)0 < 4% is at variance with the results that have provided the first evidence for the Xi(--).

Study of prostaglandin receptors in mitochondria on apoptosis of human lung carcinoma cell line A549

PGs (prostaglandins) are synthesized through the cyclo-oxygenase (COX-1 and -2) pathway in a variety of cells in response to various physiological stimuli. All cells require at least one pathway for apoptosis, and mitochondrial play a central role in regulation of apoptosis. In a previous study, incubation of A549 cells with NS-398 (a COX-2-specific inhibitor) induced apoptosis and inhibited cell proliferation, and the concentrations of different PGs between various cellular compartments were found to be changed. To determine whether PG receptors are involved in this regulation, Western-blot analyses were performed specific for PGE2 (EP receptors) and PGF2α (FP receptor) receptors, which were expressed in A549 cells. Western-blot analysis revealed that mitochondria that were isolated from A549 cells expressed EP receptors (EP2, EP3 and EP4), whereas FP receptors were undetectable. EP receptors (EP1, EP3 and EP4) and FP receptors were detected from A549 cell membrane. These results suggest that the change of PG production in A549-cells-induced cancer cell apoptosis might be related to the different expressions of EP and FP receptors in cell and mitochondrial membrane.

The metabolic syndrome and incident diabetes: assessment of four suggested definitions of the metabolic syndrome in a Chinese population with high post-prandial glucose

AIMS

To assess the sensitivity and specificity of the four definitions of the metabolic syndrome for incident diabetes in both men and women.

METHODS

The screening survey for type 2 diabetes was conducted in 1994. A follow-up study on 627 high-risk non-diabetic individuals at baseline was carried out in 1999 in Beijing area. 70 men and 76 women developed diabetes during the five-year follow-up. Sensitivity and specificity of four definitions of the metabolic syndrome based on the NCEP, WHO, EGIR and AACE recommendations were compared by McNemar's test.

RESULTS

The metabolic syndrome based on all four definitions identified men at a 3.7-4.5-fold and women at a 1.6-2.8-fold risk of developing diabetes during 5-year follow-up. The AACE definition had the highest sensitivity for predicting diabetes (men: 0.61; women: 0.58) and lowest specificity (men: 0.71; women: 0.70). The WHO definition identified 53 % of male and 42 % female incident diabetes. The NCEP definition of adiposity as waist girth > 102 cm was the least sensitive, detecting only 27 % of incident diabetes in men; however, it was the most specific (0.91). The EGIR definition identified the lowest number of female cases (28 %) and fewer male cases (28 %) of incident diabetes, but was specific (women: 0.87; men: 0.91).

CONCLUSIONS

Further studies on definition of the metabolic syndrome should focus on the potential ethnic differences in insulin resistance and anthropometric indicators for obesity.

Comparison of quantitative 99mTc-HMPAO and 67Ga citrate lung scans in patients with active diffuse infiltrative lung disease

Diffuse infiltrative lung disease (ILD) is a heterogeneous group of disorders that predominantly affect the lung parenchyma and spare the airway. To objectively assess the degree of pulmonary vascular endothelium damage in active ILD, lung/liver uptake ratios (L/L ratios) on 99mTc hexamethylpropylene amine oxime (99mTc-HMPAO) lung scans were determined in 21 patients with active ILD. Meanwhile, the 67Ga citrate uptake index (GUI) on 67Ga lung scans was measured in order to evaluate the severity of lung inflammation in active ILD. The results show there were statistically significant differences between normal controls and patients with active ILD, as shown in the L/L ratio and GUI. However, when the patients were divided into two groups: (1) eight patients with normal chest X-ray findings, and (2) 13 patients with abnormal X-ray findings, there was no significant difference between groups 1 and 2 for the results of L/L ratio and GUI. In addition, no correlation between the degree of damage to the pulmonary vascular endothelium and the severity of lung inflammation was found. In conclusion, L/L ratios on 99mTc-HMPAO lung scans and GUI on 67Ga lung scans are different to the findings of chest X-rays and have the potential to objectively detect the degree of damage to the pulmonary vascular endothelium and the severity of lung inflammation in active IDL. However, the relationship between L/L ratio and GUI in active ILD is not significant.

High prevalence of asymptomatically poor muscle perfusion of lower extremities measured in systemic lupus erythematosus patients with abnormal myocardial perfusion

Patients with systemic lupus erythematosus (SLE) may develop premature atherosclerosis, notably peripheral vascular disease (PVD) presenting with intermittent claudication or gangrene. Therefore, it is important to investigate if high prevalence of poor muscle perfusion of lower extremities in SLE patients with abnormal myocardial perfusion is related to more cardiovascular risk factors. We used a well-established and noninvasive radionuclide method (xenon 133 muscle washout) to evaluate objectively the anterior tibial muscle perfusion of 34 SLE female patients without symptoms/signs of PVD in the lower extremities. The patients were separated into two groups according to myocardial perfusion imaging results. Meanwhile, 30 normal female controls with matched age distribution were also included for comparison. The muscle perfusion differed significantly ( P <0.05) between patients (1.90+/-0.41 ml/100 g per min) and controls (2.91+/-0.50 ml/100 g per min), as well as between 18 SLE patients with abnormal myocardial perfusion (1.33+/-0.43 ml/100 g per min) and 16 with normal myocardial perfusion (2.26+/-0.45 ml/100 g per min). Based on the xenon 133 muscle washout method, we conclude that muscle perfusion in the lower extremities of SLE patients without symptoms/signs of PVD is significantly decreased and related to abnormal myocardial perfusion.

Cost utility of screening and treatment for early age related macular degeneration with zinc and antioxidants

AIM

To assess the cost effectiveness of high dose zinc and antioxidants for delaying and reducing the progression of early age related macular degeneration (AMD).

BACKGROUND

AMD is the leading cause of severe vision impairment and blindness in older people throughout the developed world. It currently affects around 420 000 people in the United Kingdom.

METHODS

A cost utility analysis (CUA) was conducted to estimate the cost per quality adjusted life year (QALY) for screening a cohort of men and women, aged 55 years and over, for early AMD and then treating them with zinc and antioxidants. The incremental CUA was based on a decision analytic model, comparing screening with a no screening comparator (current practice). Extensive one way sensitivity analysis of parameters was conducted to determine the robustness of the model.

RESULTS

In this model the cost effectiveness of screening for early AMD was pound 22 722 per quality adjusted life year (QALY) saved. The cost per QALY decreased to pound 18 948 if photodynamic therapy with verteporfin savings were included.

CONCLUSIONS

Screening for, and prophylactic treatment of, early AMD is estimated to cost around pound 22 700 per QALY saved. This cost falls within accepted levels to warrant further investigation. These findings have implications for ophthalmic practice and healthcare planning.

Antinociceptive effect of a novel long-acting nalbuphine preparation †

BACKGROUND

A long-acting analgesic may be particularly desirable in patients suffering from long-lasting pain. The aim of the study was to evaluate the antinociceptive effect of a novel nalbuphine preparation and to determine its duration of action.

METHODS

The antinociceptive effects of i.m. nalbuphine HCl in saline and nalbuphine base in sesame oil were evaluated in rats. The in vitro drug-releasing profiles of nalbuphine HCl and base in different preparations were also evaluated.

RESULTS

We found that i.m. nalbuphine HCl 25, 50 and 100 micromol kg(-1) produced dose-related antinociceptive effects with a duration of action of 1.5, 2 and 3 h, respectively. i.m. nalbuphine base 100, 200 and 400 micromol kg(-1) also produced dose-related antinociceptive effects but with longer durations of action: 27, 49 and 55 h, respectively. In vitro studies demonstrated that nalbuphine base in sesame oil had the slowest drug-releasing profile of the different preparations.

CONCLUSIONS

i.m. injection of an oil formulation of nalbuphine base produced a long-lasting antinociceptive effect.

Wave propagation in a model of the arterial circulation

The propagation of the arterial pulse wave in the large systemic arteries has been calculated using a linearised method of characteristics analysis to follow the waves generated by the heart. The model includes anatomical and physiological data for the 55 largest arteries adjusted so that the bifurcating tree of arteries is well matched for forward travelling waves. The peripheral arteries in the model are terminated by resistance elements which are adjusted to produce a physiologically reasonable distribution of mean blood flow. In the model, the pressure and velocity wave generated by the contraction of the left ventricle propagates to the periphery where it is reflected. These reflected waves are re-reflected by each of the bifurcations that they encounter and a very complex pattern of waves is generated. The results of the calculations exhibit many of the features of the systemic arteries, including the increase of the pulse pressure with distance away from the heart as well as the initial decrease and then the large increase in the magnitude of back flow during late systole going from the ascending aorta to the abdominal aorta to the arteries of the leg. The model is then used to study the effects of the reflection or absorption of waves by the heart and the mechanisms leading to the incisura are investigated. Calculations are carried out with the total occlusion of different arterial segments in order to model experiments in which the effects of the occlusion of different arteries on pressure and flow in the ascending aorta were measured. Finally, the effects of changes in peripheral resistance on pressure and velocity waveforms are also studied. We conclude from these calculations that the complex pattern of wave propagation in the large arteries may be the most important determinant of arterial haemodynamics.

Developmental aspects of ovine adrenal adrenocorticotropic hormone receptor expression

OBJECTIVE

Maturation of adrenocortical function is important because a prepartum increase in fetal plasma glucocorticoids is required for survival after birth. Adrenal maturation may include alterations in the regulation of adrenocorticotropic hormone (ACTH) receptor expression. Therefore, we quantitated ACTH receptor expression in the ovine adrenal cortex during development and after manipulations to better understand the regulation of the adrenal receptor in vivo.

METHODS

For the ontogeny study, adrenals were obtained from fetuses at different stages of development, and the cortical tissue was stored at -80C until total RNA was extracted. The ACTH binding studies were done on adrenal membranes obtained from fetuses at two different ages using I125 (Phe-2, Nle-4) ACTH as the ligand. Plasma ACTH was measured by two-site immunoradiometric assay, and cortisol was measured by radioimmunoassay. ACTH receptor mRNA was quantitated by ribonuclease protection assay. The data were analyzed by analyses of variance.

RESULTS

ACTH receptor mRNA level progressively increased in fetal life; relative changes in receptor mRNA and binding were similar (3.0-fold and 2.4-fold, respectively). Physiologic increases in fetal plasma cortisol decreased adrenal ACTH receptor mRNA concentration, and there was a strong (r2=0.76, P<.002) linear relationship between fetal plasma ACTH concentration and receptor mRNA levels. Receptor mRNA stability increased in development, and message half-life was greater in adulthood than in fetal life.

CONCLUSION

The data suggest that developmental increases in receptor expression are part of the maturation process in the fetal adrenal and that plasma ACTH concentration plays a major role in regulating ACTH receptor mRNA levels in vivo.