Fisher information analysis of list-mode SPECT emission data for joint estimation of activity and attenuation distribution.

The potential to perform attenuation and scatter compensation (ASC) in single-photon emission computed tomography (SPECT) imaging without a separate transmission scan is highly significant. In this context, attenuation in SPECT is primarily due to Compton scattering, where the probability of Compton scatter is proportional to the attenuation coefficient of the tissue and the energy of the scattered photon and the scattering angle are related. Based on this premise, we investigated whether the SPECT scattered-photon data acquired in list-mode (LM) format and including the energy information can be used to estimate the attenuation map. For this purpose, we propose a Fisher-information-based method that yields the Cramer-Rao bound (CRB) for the task of jointly estimating the activity and attenuation distribution using only the SPECT emission data. In the process, a path-based formalism to process the LM SPECT emission data, including the scattered-photon data, is proposed. The Fisher information method was implemented on NVIDIA graphics processing units (GPU) for acceleration. The method was applied to analyze the information content of SPECT LM emission data, which contains up to first-order scattered events, in a simulated SPECT system with parameters modeling a clinical system using realistic computational studies with 2-D digital synthetic and anthropomorphic phantoms. The method was also applied to LM data containing up to second-order scatter for a synthetic phantom. Experiments with anthropomorphic phantoms simulated myocardial perfusion and dopamine transporter (DaT)-Scan SPECT studies. The results show that the CRB obtained for the attenuation and activity coefficients was typically much lower than the true value of these coefficients. An increase in the number of detected photons yielded lower CRB for both the attenuation and activity coefficients. Further, we observed that systems with better energy resolution yielded a lower CRB for the attenuation coefficient. Overall, the results provide evidence that LM SPECT emission data, including the scattered photons, contains information to jointly estimate the activity and attenuation coefficients.

Urinary iodine deficiency in Gippsland pregnant women: the failure of bread fortification?

OBJECTIVE: To assess iodine status and the factors that influence iodine status among a cohort of pregnant women living in Gippsland. DESIGN, PARTICIPANTS AND SETTING: Cross-sectional study of 86 pregnant women (at ≥ 28 weeks' gestation) conducted in hospital antenatal care services and private obstetrician clinics across the Gippsland region of Victoria, Australia, from 13 January 2009 to 17 February 2010. MAIN OUTCOME MEASURES: Overall proportion of pregnant women with a urinary iodine concentration (UIC) > 150 µg/L; proportion of pregnant women with a UIC >150 µg/L after the mandatory iodine fortification of bread; use of supplements containing iodine; intake of foods known to be good sources of iodine; intake of bread. RESULTS: The percentage of pregnant women with UIC >150 µg/L (indicative of iodine sufficiency) was 28%. There was no statistically significant difference in UICs before and since iodine fortification of bread. The median UIC before fortification was 96 µg/L (interquartile range [IQR], 45-153 µg/L) and since fortification was 95.5 µg/L (IQR, 60-156 µg/L). The dietary intake of iodine-rich food (including bread) and the use of appropriate supplements was insufficient to meet the increased iodine requirements during pregnancy. CONCLUSIONS: The UICs in this cohort of pregnant women are of concern, and seem unlikely to be improved by the national iodine fortification program. Pregnant women in Gippsland urgently need effective iodine education programs and encouragement to either consume iodine-rich foods or take appropriate supplements.

Is Gippsland environmentally iodine deficient? Water iodine concentrations in the Gippsland region of Victoria, Australia.

OBJECTIVE: This paper provides evidence of environmental iodine deficiency in the Gippsland region. DESIGN: Quantitative study; water samples were collected from 18 water treatment plants and four rain water tanks across Gippsland and water iodine concentrations were measured. SETTING: Gippsland region of Victoria, Australia. MAIN OUTCOME MEASURES: This paper reports on the iodine concentration of drinking water from sources across Gippsland and examines the contribution of iodine from water to the Gippsland diet. This study also briefly examines the relationship between the concentration of iodine in water and distance from the sea. The cut-off value for water iodine concentrations considered to be indicative of environmental iodine deficiency is <2 µg L(-1) . RESULTS: The mean iodine concentration of water from 18 Gippsland water treatment plants was 0.38 µg L(-1) and would therefore make negligible difference to the dietary intake of iodine. This finding also falls well below the suggested dietary intake of iodine from water estimated by the 22nd Australian Total Diet Study. Our study found no linear relationship between the water iodine concentration and distance from the sea. CONCLUSION: As Gippsland has environmental iodine deficiency there is a greater probability that people living in this region are at higher risk of dietary iodine deficiency than those living in environmentally iodine sufficient regions. Populations living in areas known to have environmental iodine deficiency should be monitored regularly to ensure that problems of iodine deficiency, especially amongst the most vulnerable, are addressed promptly.

Taking a history: the learnings that national health science forgot.

OBJECTIVE: This paper provides evidence for the importance of taking an effective history and considering regional differences before formulating national health policies. DESIGN: Qualitative study; the data collection technique included manual searches of rare book collections, a search of the Victorian Public Record Office and Australian Archives files and a local media appeal for information about iodine and iodine supplementation in Gippsland and other regions of Australia. SETTING: Regional Victoria and Australia as a whole. PARTICIPANTS: A total of 17 community members from the Gippsland region provided information on taking iodine tablets between the late 1940s and the late 1960s. MAIN OUTCOME MEASURES: Information from the community members who took iodine tablets, archival material, published papers in journals on iodine deficiency disorder in Gippsland, government reports and meeting minutes regarding distribution of iodine supplementation in Gippsland. RESULTS: Taking an effective history is vital to planning national health interventions. It might not be adequate to just search electronic databases. A thorough search of archival and hard copy material and consultation with members of the population can help find key historical data that can inform better health policy action. CONCLUSION: There is strong historical evidence of dietary iodine deficiency in the Gippsland region and in a number of other regions across Australia. Government and health authorities should undertake regular iodine status monitoring in these regions. Considering regional difference is important when making national health policy.

Increased iodine deficiency in Victoria, Australia: analysis of neonatal thyroid-stimulating hormone data, 2001 to 2006.

OBJECTIVE: To use neonatal thyroid-stimulating hormone (TSH) concentration data to measure the iodine status of the population of the Australian state of Victoria. DESIGN, PARTICIPANTS AND SETTING: Retrospective analysis of the results of 368,552 neonatal heel-prick blood tests for TSH concentration in Victoria in the years 2001-2006. MAIN OUTCOME MEASURES: Iodine deficiency as indicated by a mean percentage of neonatal TSH concentrations > 5 mIU/L of over 3% in accordance with World Health Organization, United Nations Children's Fund and International Council for the Control of Iodine Deficiency Disorder criteria; comparison of findings for the nine Department of Human Services health regions in Victoria. RESULTS: The mean percentage of neonatal TSH concentrations > 5 mIU/L ranged from 4.07% in 2001 to 9.65% in 2006, and this increase was statistically significant (P < 0.001). The populations of all nine Victorian health regions showed increasing iodine deficiency over the study period. Metropolitan populations had higher iodine deficiency than non-metropolitan populations, and this difference was also statistically significant (P < 0.05). These results are consistent with urinary iodine excretion research in Victoria. CONCLUSIONS: The high percentage of elevated TSH concentrations among newborns is of concern and requires ongoing monitoring. Neonatal TSH assay is part of routine screening in Australia, and thus offers an effective and economical method of monitoring population iodine status.

Comparison of risks and benefits of normal vaginal and caesarian section deliveries in a public tertiary hospital in Bangladesh.

A comparative study was done to compare risks and benefits of normal vaginal and caesarean section delivery. One hundred women between 36 to 40 weeks gestation were enrolled and face to face interviews and clinical assessments were conducted both in antenatal and postnatal period. Though 98% preferred vaginal birth only 45% eventually had so. Both immediate and late complications were considerably more in caesarian section than in normal vaginal delivery. Mean duration of sickness and mean days required for returning to normal activities were also higher in case of caesarian section. The average cost for Caesarian was $70 while for normal vaginal delivery it was $28. Caesarean delivery has some associated risks and complications. It is expensive than normal vaginal delivery. It will help practitioners to reduce the rate of primary caesarean delivery and the pregnant mothers should be informed about risks and benefits of various birth options.

A randomised intervention trial to assess two arsenic mitigation options in Bangladesh.

Arsenic groundwater contamination in Bangladesh warrants immediate remediation. This randomised controlled intervention trial was conducted to determine the effectiveness of two possible interventions: dug wells and three-pitcher filters. A total of 640 individuals participated with 218 randomised to the dug well group, 216 to the three-pitcher group and 206 to a control group. Data were collected at baseline and at 1, 6 and 12 months after the intervention. Self reported compliance with dug wells remained below 20% during the entire 12 months of the study. The compliance with the three-pitcher filters decreased after 6 months and became similar to the compliance of the dug well group after 12 months. A substantial decrease in urinary arsenic metabolites occurred only among those who were compliant with dug wells and three-pitcher filter systems after 1 month of intervention as opposed to control participants. However, a persistent reduction in urinary arsenic concentrations was observed only among the dug well users after 12 months of intervention. Our results show that a functional dug well could be offered as a long-term alternative to tube wells, but use of this option is likely to be low, unless appropriate behavioural change measures are taken. Our study also demonstrates that arsenic removal technologies such as three-pitcher filters are an effective option as a short-term measure. The three-pitcher filters that are not adequately maintained are not an effective option for a year. These arsenic removal technologies may be even harmful in the long term if the resultant water quality is not properly monitored.

Effect of Usuhiratake (Pleurotus pulmonarius) on sneezing and nasal rubbing in BALB/c mice.

The anti-rhinitis properties of Pleurotus pulmonarius were investigated in BALB/c mice. A single administration of Pleurotus Pulmonarius caused no significant effect on antigen-induced nasal rubbing and sneezing at a dose of 500 mg/kg, but a significant inhibition was observed after 2 weeks of repeated treatment at this dose, and at a dose of 200 mg/kg, it also caused a significant inhibition after repeated administration for 4 weeks. Pleurotus pulmonarius showed no significant inhibitory effect on the production of IgE. In addition, Pleurotus pulmonarius caused no inhibition of histamine-induced nasal rubbing and sneezing at a dose of 500 mg/kg, but in vitro study, it inhibited histamine release from rat mast cells induced by compound 48/80 at the soluble supernatant solution of 30 and 100 microg/ml of Pleurotus pulmonarius suspended in PBS. These results demonstrated that Pleurotus pulmonarius may be effective in the relief of symptoms of allergic rhinitis through inhibition of histamine release.

Influences of histamine H1 receptor antagonists on maximal electroshock seizure in infant rats.

The influences of histamine H1 receptor antagonists on maximal electroshock seizure were studied using infant rats. In this study, electroconvulsion was induced by stimulating rats using ear-clip electrodes, and the durations of electroencephalogram (EEG) seizure, tonic extensor (TE) seizure and clonic (CL) seizure induced by maximal electroshock were measured. Diphenhydramine, chlorpheniramine, cyproheptadine and ketotifen caused a dose-dependent and significant prolongation of both EEG seizure and TE seizure induced by maximal electroshock. On the other hand, epinastine and fexofenadine caused no such effects, even at a dose of 50 mg/kg. All drugs used in this study showed no significant effect on CL seizure induced by maximal electroshock. From these findings, it is suggested that epinastine and fexofenadine may cause no harmful influence on epilepsy, even when used in a little child.

Interactive effect of histamine and prostaglandin D2 on nasal allergic symptoms in rats.

This study was undertaken to investigate the interactive effect of histamine and prostaglandin D(2) in nasal allergic symptoms in rats. The intranasal application of histamine at doses lower than 10 mumol/site caused no sneezing or nasal rubbing. In addition, prostaglandin D(2) also showed no significant increase in these responses, even at a dose of 10 nmol/site. On the other hand, the simultaneous instillation of histamine and prostaglandin D(2) resulted in a 1000 times more potent effect in inducing nasal symptoms than the administration of histamine alone. Thus, prostaglandin D(2) enhanced the actions of histamine in inducing sneezing and nasal rubbing in a dose-dependent manner, and significant effects were observed at doses higher than 1 nmol/site. The responses induced by the simultaneous application of histamine and prostaglandin D(2) were inhibited by chlorpheniramine, cyproheptadine, BW A868C and ramatroban. Chlorpheniramine and cyproheptadine showed the dose-related inhibition of nasal symptoms induced by the combined administration of histamine (10 nmol) and prostaglandin D(2) (10 nmol), but the effect of cyproheptadine was relatively weak compared with chlorpheniramine. Moreover, BW A868C and ramatroban also showed the inhibition of nasal symptoms induced by the simultaneous administration of histamine and prostaglandin D(2) in a dose-dependent manner. BW A868C was more potent in inhibiting the nasal symptoms than ramatroban. These results clearly indicate that prostaglandin D(2) showed a synergistic effect on sneezing and nasal rubbing induced by histamine in rats, and its effect occurred through both prostaglandin D(2) and CRTH2 (chemoattractant receptor-homologous molecule expressed on TH2 cells) receptors.

Epileptogenic activity of methicillin-resistant Staphylococcus aureus (MRSA) antibiotics in rats.

The present study was undertaken to clarify the epileptogenic activity induced by intracerebroventricular injection (i.c.v.) of antibiotics effective in methicillin-resistant Staphylococcus aureus (MRSA) in chronically electrode implanted rats. Teicoplanin (10-100 microg, i.c.v.) caused dose-related electroencephalographic (EEG) seizure characterized by an uninterrupted high voltage and wave complex. At the same time, the rats showed forelimb clonus, head nodding, jumping and severe convulsion. At a high dose (100 microg, i.c.v.), the drug caused a severe twisting immediately after the intracerebroventricular injection (i.c.v.) followed by jumping and violent convulsion with a continuous rhythmic spike and wave complex in EEG. On the other hand, vancomycin (30-1000 microg, i.c.v.) caused no or almost no epileptogenic activity in terms of behavior and in EEG. However, at a high dose (1000 microg, i.c.v.), the drug caused an occasional spike from the hippocampus without showing any behavioral changes in the rats. Fosfomycin (30-1000 microg, i.c.v.), cefazolin (10-100 microg, i.c.v.) and penicillin G (30-300 microg, i.c.v.), used as reference drugs, caused dose-dependent epileptogenic activity in both EEG. From these findings, it was found that teicoplanin caused a potent epileptogenic activity, different to vancomycin. Therefore, it can be concluded that vancomycin may be safety on epileptogenic activity used for the clinical purpose of infections caused by MRSA.

Involvement of cyclooxygenase-2 in allergic nasal inflammation in rats.

This study was undertaken to investigate the involvement of cyclooxygenase-2 (COX-2) in allergic nasal inflammation in actively sensitized rats. An allergic rhinitis model was developed by the repeated topical application of antigen into the nasal cavities in the sensitized rats. The severity of allergic rhinitis was studied by measuring the nasal behavior, as well as electroencephalogram (EEG) activity by antigen challenge. The electrodes were implanted chronically into the bilateral olfactory bulb of the rats and the EEG was measured monopolarly with an electroencephalograph (EEG, Nohon Kohden, Japan). The intranasal application of antigen caused the increase of nasal allergic signs as well as an EEG spike in a dose-dependent fashion, and at a dose of 50 microg/site, it showed a significant effect. The responses induced by the antigen were evaluated with certain drugs, etodolac (a selective COX-2 inhibitor), indomethacin (a non-selective COX inhibitor), ramatroban (a thromboxane A2 receptor antagonist) and zafirlukast (a cys-leukotriene receptor antagonist). Etodolac showed the inhibition of nasal behavior and EEG spike in a dose-related fashion, and at doses of 3 and 10 mg/kg, it showed a significant effect. Moreover, ramatroban also caused the dose-related inhibition of nasal behavior and EEG spike induced by antigen. On the other hand, both indomethacin and zafirlukast had no effects on the responses induced by antigen, even at a higher dose. Therefore, it can be concluded that cyclooxygenase-2 actively participates in the allergic nasal inflammation in actively sensitized rats.

Effects of mometasone furoate on a rat allergic rhinitis model.

The present study was undertaken to clarify the effects of mometasone on nasal symptoms induced by repeated intranasal application of antigen in sensitized rats in comparison with that of chlorpheniramine. Rats received mometasone intranasally or chlorpheniramine orally 1 h before a topical antigen challenge for 7 days. Mometasone caused a decrease in the instances of nasal rubbing and an inhibition of this response was observed during the treatment period. Almost identical findings were observed with chlorpheniramine. This response was inhibited, even after the interruption of mometasone treatment, while such an effect was not observed with chlorpheniramine. On day 36, the changes in sensitivity to histamine were investigated. Unlike chlorpheniramine, hypersensitivity to histamine was significantly reduced in the mometasone-treated group. The passive cutaneous anaphylaxis titers were elevated and reached a maximum 8 days after the start of the topical antigen challenge. The passive cutaneous anaphylaxis titer in the mometasone-treated group was significantly lower than that in the control group. The results indicated that mometasone is effective in allergic rhinitis, not only during the period of application, but also after the interruption of application.