Comparative renal, hepatic, and bone marrow toxicity of Cisplatin and radioactive Cisplatin (191Pt) in Wistar rats

The aim of the study was to investigate the possibility to increase the therapeutic gain of the cytotoxic agent, cisplatin, by incorporation of radioactive platinum. In this study, we investigated how organs at risk (i.e., kidneys, bone marrow, and liver) are affected by treatment with 191Pt-cisplatin, compared to treatment with conventional cisplatin. Rats (total, n = 69) were divided into three groups and given 5 mg/kg 191Pt-cisplatin and 5 mg/kg nonradioactive cisplatin or saline. The weight of the animals and blood samples, including analysis of creatinine, bilirubin, alanine and aspartate aminotransferases and platelet count, was followed for 6 weeks after treatment. Histopathology examinations of kidney and liver tissues were performed. An initial decrease in weight gain was seen from 3 days after treatment with cisplatin and 191Pt-cisplatin and for 1 week onward; thereafter, the weight gain continued, following the same pattern as for the control group. Concentration of plasma creatinine was increased for both cisplatin groups but with no significant difference between treatment groups. No other significant differences in effect parameters were found. There was no increase in toxicity for radioactive cisplatin on liver, kidneys, and bone marrow, compared to conventional cisplatin. Further experimental and clinical studies on preparations of this type are thus warranted.

Regulation of OX1 orexin/hypocretin receptor-coupling to phospholipase C by Ca2+ influx

BACKGROUND AND PURPOSE

Orexin (OX) receptors induce Ca2+ elevations via both receptor-operated Ca2+ channels (ROCs) and the "conventional" phospholipase C (PLC)-Ca2+ release-store-operated Ca2+ channel (SOC) pathways. In this study we assessed the ability of these different Ca2+ influx pathways to amplify OX1 receptor signalling to PLC in response to stimulation with the physiological ligand orexin-A.

EXPERIMENTAL APPROACH

PLC activity was assessed in CHO cells stably expressing human OX1 receptors.

KEY RESULTS

Inhibition of total Ca2+ influx by reduction of the extracellular [Ca2+] to 1 microM effectively inhibited the receptor-stimulated PLC activity at low orexin-A concentrations (by 93% at 1 nM), and this effect was gradually reduced by higher orexin-A concentrations. A similar but weaker inhibitory effect (84% at 1 nM) was obtained on depolarization to approximately 0 mV, which disrupts most of the driving force for Ca2+ entry. The inhibitor of the OX1 receptor-activated ROCs, tetraethylammonium chloride (TEA), was somewhat less effective than the reduction in extracellular [Ca2+] at inhibiting PLC activation, probably because it only partially blocks ROCs. The partial inhibitor of both ROCs and SOCs, Mg2+, and the SOC inhibitors, dextromethorphan, SKF-96365 (1-[beta-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenethyl]-1H-imidazole HCL) and 2-APB (2-aminoethoxydiphenyl borate), inhibited PLC activity at low concentrations of orexin-A, but were not as effective as TEA.

CONCLUSIONS AND IMPLICATIONS

Both ROCs and SOCs markedly amplify the OX(1) receptor-induced PLC response, but ROCs are more central for this response. These data indicate the crucial role of ROCs in orexin receptor signalling.

The analysis of 51 genes in DSM-IV combined type attention deficit hyperactivity disorder: association signals in DRD4, DAT1 and 16 other genes

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, starting in early childhood and persisting into adulthood in the majority of cases. Family and twin studies have demonstrated the importance of genetic factors and candidate gene association studies have identified several loci that exert small but significant effects on ADHD. To provide further clarification of reported associations and identify novel associated genes, we examined 1,038 single-nucleotide polymorphisms (SNPs) spanning 51 candidate genes involved in the regulation of neurotransmitter pathways, particularly dopamine, norepinephrine and serotonin pathways, in addition to circadian rhythm genes. Analysis used within family tests of association in a sample of 776 DSM-IV ADHD combined type cases ascertained for the International Multi-centre ADHD Gene project. We found nominal significance with one or more SNPs in 18 genes, including the two most replicated findings in the literature: DRD4 and DAT1. Gene-wide tests, adjusted for the number of SNPs analysed in each gene, identified associations with TPH2, ARRB2, SYP, DAT1, ADRB2, HES1, MAOA and PNMT. Further studies will be needed to confirm or refute the observed associations and their generalisability to other samples.

Macrophage uptake of ultra-small iron oxide particles for magnetic resonance imaging in experimental acute cardiac transplant rejection

PURPOSE

To discriminate between acutely rejecting and non-rejecting transplanted hearts using a blood pool contrast agent and T2* magnetic resonance imaging (MRI) in a clinical 1.5T scanner.

MATERIAL AND METHODS

Allogeneic and syngeneic heterotopic heart transplantations were performed in rats. One allogeneic and one syngeneic group each received either the ultra-small iron oxide particle (USPIO), at two different doses, or no contrast agent at all. MRI was performed on postoperative day 6. Immediately after the MR scanning, contrast agent was injected and a further MRI was done 24 h later. Change in T2* was calculated.

RESULTS

No significant difference in change in T2* could be seen between rejecting and non-rejecting grafts in either of the doses, or in the control groups. There was a difference between the allogeneic group that received the higher contrast agent dose and the allogeneic group that did not receive any contrast agent at all.

CONCLUSION

In our rat model, measurements of T2* after myocardial macrophage uptake of AMI-227 in a clinical 1.5T scanner were not useful for the diagnosis of acute rejection.

Relations between high ponderal index at birth, feeding practices and body mass index in infancy

OBJECTIVE

We compared feeding practices between infants of high ponderal index (PI) at birth (PI above the 90th percentile) and normal PI at birth (PI between 10th and 90th percentiles), and examined how birth size and infant feeding practices were related to body mass index (BMI) at 12 months.

DESIGN

In a cohort of 3000 infants invited to participate in a national Norwegian dietary survey, 1825 participated both at 6 and 12 months of age, and the present study included those born full term and with a PI (weight/length3) at birth > or =10th percentile (n=1441). Data on feeding practices were collected by food-frequency questionnaires, and anthropometrical data were measured by health-care personnel.

RESULTS

A lower proportion of infants born with high PI were exclusively breastfed for at least 4 months compared with infants born with normal PI (37 and 47%, respectively; P=0.03). Earlier introduction of solid foods and higher consumption of some foods were also observed among infants of high PI. In a multivariate analysis, adjusted mean BMI (kg/m2) at 12 months was higher for infants of high PI at birth than for infants of normal PI (17.6 and 17.0, respectively; P<0.001) and higher for infants exclusively breastfed <3 months than for infants exclusively breastfed > or =3 months (17.5 and 17.2, respectively; P=0.001).

CONCLUSIONS

High PI at birth was associated with a shorter duration of exclusive breastfeeding. Furthermore, high PI at birth and short-term exclusive breastfeeding were both associated with higher BMI at 12 months.

Lipoprotein profiles in plasma and interstitial fluid analyzed with an automated gel-filtration system

BACKGROUND

High-quality methods for lipoprotein characterization are warranted in studies on various metabolic diseases.

MATERIALS AND METHODS

An automated system for size-exclusion chromatography (SEC) of lipoproteins using commercially available components is described. Cholesterol or triglyceride content in separated lipoproteins from plasma and interstitial fluid (IF) was continuously determined on-line using microlitre sample volumes.

RESULTS

The lipoprotein assay showed a good concordance with the classic ultra-centrifugation/precipitation technique using fresh or frozen samples. Determination of lipoproteins in IF obtained from vacuum-induced skin blisters from 18 healthy subjects revealed that very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol levels were 18%, 19% and 25%, respectively, of concomitant plasma concentrations. The size-exclusion chromatography (SEC) system also allows for triglyceride determination on-line and it could be shown that the system is advantageous for an accurate determination of triglycerides in conditions when there are high levels of glycerol, e.g. in mice and in patients with hyperglycerolaemia (pseudo-hypertriglyceridaemia).

CONCLUSIONS

The described system should be of value in studies where detailed lipoprotein analysis is warranted and particularly when significant sample series with small volumes are available. Our data also suggest that there is a 4-5.5-fold concentration gradient between plasma and IF for the three major plasma lipoproteins.

Quantification of intramyocellular lipids in obese subjects using spectroscopic imaging with high spatial resolution

Quantification of intramyocellular lipids (IMCL) in obese subjects by single-voxel spectroscopy (SVS) or conventional spectroscopic imaging (SI) often fails due to overlap of IMCL spectral lines by extramyocellular lipids (EMCL), and signal contamination from subcutaneous fat and bone marrow. This study demonstrates that these problems can be solved by high-resolution SI with 128 phase-encoding steps and a read gradient during acquisition. The small voxels obtained in this way facilitated differentiation between EMCL and IMCL. This method offers the possibility of studying different muscle groups and the variation of lipids within one muscle.

The amount of informal and formal care among non-demented and demented elderly persons-results from a Swedish population-based study

BACKGROUND

Developed countries are experiencing a dramatic increase in the proportion of elderly persons, as well as a progressive aging of the elderly population itself. Knowledge regarding the amount of formal and informal care and its interaction at population-based level is limited.

OBJECTIVES

To describe the amount of formal and informal care for non-demented and demented persons living at home in a population-based sample.

METHODS

The population consisted of all inhabitants, 75 + years, living in a rural community (n = 740). They were clinically examined by physicians and interviewed by nurses. Dementia severity was measured according to Washington University Clinical Dementia Rating Scale (CDR). Informal and formal care was examined with the RUD (Resource Utilization in Dementia) instrument.

RESULTS

The amount of informal care was much greater than formal care and also greater among demented than non-demented. There was a relationship between the severity of the cognitive decline and the amount of informal care while this pattern was weaker regarding formal care. Tobit regression analyses showed a clear association between the number of hours of informal and formal care and cognitive decline although this pattern was much stronger for informal than formal care.

CONCLUSIONS

Informal care substitutes rather than compliments formal care and highlights the importance of future studies in order to truly estimate the amount of informal and formal care and the interaction between them. This knowledge will be of importance when planning the use of limited resources, and when supporting informal carers in their effort to care for their intimates.

Experimental disease models for the assessment of meningococcal vaccines

Animal infection models are valuable for the development and preclinical assessment of meningococcal vaccines in the absence of clear in vitro correlates of protection for protein-based serogroup B vaccines. It is only in animal models that interactions of the organism with the innate, humoral and cellular immune systems can be assessed. However, humans are the only natural host for Neisseria meningitidis and there is no ideal disease model using laboratory animals that mimics the course of human disease. The two most widely used models are intraperitoneal (i.p.) infection of adult mice or infant rats. The mouse i.p. infection model requires an exogenous iron source (e.g. human transferrin) to obtain a lethal bacteraemic infection and can be used to assess both active and passive immunisation. The virulence of wild-type and knockout mutants can also be compared. i.p. infection of infant rats has been used to assess passive protection provided by sera raised against vaccine candidates or human vaccine sera. However, the duration of bacteraemia is short, mortality is low and active protection cannot be assessed. Recent developments using transgenic mice expressing human CD46 give hope that improved models will be developed.

Leptin, but not adiponectin, predicts stroke in males

OBJECTIVE

To test whether leptin and adiponectin are risk markers for a first-ever stroke. RESEARCH DESIGN, METHODS AND SUBJECTS: A nested case-referent study identified 276 cases with first-ever stroke (234 cases with ischaemic and 42 with haemorrhagic stroke). Prior to the stroke, they had participated in population-based health surveys in northern Sweden (median time between survey and stroke was 4.9 years). Referents were matched for sex, age, date and type of health survey, and geographical region. Putative risk markers for first-ever stroke, including blood pressure (BP), diabetes, smoking, body mass index (BMI), cholesterol, leptin, and adiponectin, were analysed by conditional logistic regression analysis.

RESULTS

Increased BMI, high cholesterol and fasting glucose levels, diabetes mellitus and hypertension were found in future stroke patients. Whereas leptin levels were higher in male subjects (P = 0.004), adiponectin did not differ between groups. A high leptin level independently predicted stroke in men (OR = 2.46; 95% CI 1.08-5.62) but not in women. Adiponectin levels did not predict stroke. Males with high leptin levels developed stroke faster than males with low leptin levels (P = 0.0009), independently of traditional risk factors.

CONCLUSIONS

Leptin may be an important link to the development of cerebrovascular disease in men, whereas adiponectin does not associate with future stroke.

Disparities in food habits in Europe: systematic review of educational and occupational differences in the intake of fat

BACKGROUND

A higher socio-economic level is associated with healthier dietary habits. Nevertheless, socio-economic differences in the intake of fat have not consistently been reported in Europe. The objective of our study was to systematically assess differences in total fat (TF) intake and saturated fat (SF) intake across social groups.

METHODS

Representative samples from nine European countries were used to perform a meta-analysis of surveys between 1985-1999, including both published and nonpublished results.

RESULTS

Because important heterogeneity was found and the estimates for TF from Spain and Estonia were different from all others, we calculated the differences in intake excluding these two countries. We found a lower TF intake in the highest (versus the lowest) occupational level both for men (difference: -1.1% of total energy intake; 95% CI: -1.3 to -0.8%) and women (difference: -0.9%; 95% CI: -1.2 to -0.6%) when Estonia and Spain were excluded.

CONCLUSION

European surveys indicate that people in the lowest category of occupation consume more fat and SF than people in the highest category.

Adult day care for dementia: a comparison of programs in Sweden and the United States

Adult day care is regarded as an important respite service to family caregivers of dementia patients to assist the patient to remain in the community. This study includes 178 Swedish and 86 American day care centers serving cognitively impaired clients. Client, staff and organizational characteristics were surveyed. Although the two countries have quite different systems of elder care, client characteristics were similar, suggesting that adult day care centers are a convergent solution to a common problem of supporting disabled elderly. Differences were found between the USA and Sweden in the staff, structure, and services of the programs. The study raises questions about day care centers' goals and organization. Results provide a clearer understanding of the optimal role and function of adult day care centers.

Clinical relevance of nasal polyps in individuals recruited from a general population-based study

OBJECTIVE

To compare the clinical presentations of individuals with nasal polyps detected by endoscopy in a general population sample with those of patients with nasal polyp disease seeking medical attention.

MATERIAL AND METHODS

A total of 38 individuals with nasal polyps from a population-based sample were compared with 38 matched controls and a third group consisting of 44 patients who presented to an outpatient clinic with symptoms and diagnosed nasal polyps Upper and lower airway symptoms were registered. Polyp size, peak nasal inspiratory flow (PNIF), olfactory function and health-related quality of life were measured.

RESULTS

Compared with the individuals with nasal polyps in the population sample, patients actively seeking medical care for nasal polyposis experienced more symptoms of nasal blockage and an impaired sense of smell, and had more extensive polyps and reduced PNIF. There were equal frequencies of asthma symptoms in these two groups. Compared with the controls, the individuals with nasal polyps in the population sample had a greater frequency of asthma symptoms and aspirin intolerance and also experienced an impaired sense of smell.

CONCLUSION

Nasal polyps alone, as seen occasionally, are indicative of airway disease involving the upper and lower respiratory tracts.

Biokinetics of iodide in man: refinement of current ICRP dosimetry models

A compartmental model describing the distribution and retention of radioactive iodide in thyroid and other organs is presented. The model is developed from published ICRP models. It is designed primarily for radiation dosimetry of iodine radionuclides used in nuclear medicine, but may also be useful for occupational radiation protection. In the proposed model, the distribution of iodide to the thyroid is assumed to be more rapid than in earlier models. Uptakes in stomach wall and salivary glands are considered, and the absorbed doses to these organs calculated. The partitioning of iodide between stomach wall and content is also discussed. Recirculation of organic iodine is also taken into account. Age-dependent half-times for iodide in the thyroid, as well as for organically-bound iodine are presented. The proposed model is applicable for dose estimations with different uptakes in the thyroid as well as for the situation when the thyroid is blocked, completely or incompletely.

The importance of adjusting for differences in proximal and distal contrast bolus arrival times in contrast-enhanced iliac artery magnetic resonance angiography

We tested the hypothesis that differences in proximal and distal contrast bolus arrival times may result in insufficient vascular signal in the distal part of the aortoiliofemoral territory with routinely used timing techniques. The difference in arrival time of the contrast medium bolus between the aorta and the common femoral arteries was measured in 14 patients undergoing magnetic resonance angiography of the aortoiliac arteries. A dual-station test bolus technique adjusting for this difference was evaluated. The variation coefficient of the signal intensity in six defined locations and signal intensities (SI) normalised to fat were calculated. Comparisons were made with findings in 13 patients examined with a fluoroscopically triggered timing technique (BolusTrak, Philips Medical Systems, Best, The Netherlands). The difference in bolus arrival time between proximal and distal vessels was 0-7 s. In 3 of 14 patients it was 5.6-7 s. There was a tendency towards a lower mean variation coefficient in the dual-station group ( p=0.10). With both techniques, significantly lower SIs were measured in the femoral arteries compared with SIs in the superior part of the abdominal aorta. In two cases in the BolusTrak group, a distal vessel could not be delineated but was shown to be patent on a delayed scan. Differences in contrast medium arrival time along the vessel may be large enough to preclude visualisation of distal vessels unless there is compensation. A dual-station test bolus technique taking this into account was found to be feasible.

A method for attenuation and scatter correction of brain SPECT based on computed tomography images

A method for attenuation and scatter correction of brain single photon emission computed tomography (SPECT) is described where computed tomography (CT) images of the brain are used for the calculation of attenuation maps. The method is evaluated for the substance 99mTc hexamethylpropylene amine oxime. A transmission dependent scatter correction is utilized and is based on ray sums calculated through the attenuation map. A method based on external markers is used to align the SPECT and CT image volumes. The markers need only to be present during the SPECT acquisition since the corresponding landmarks can be found without markers on the CT images. The mismatching has been investigated for five patients who have undergone both a CT examination and a SPECT examination with markers. Twelve individuals from the staff have pointed out the landmarks on the CT images, with an average standard deviation of 3.4 mm. Reconstructions with an attenuation map shifted the corresponding 95% confidence interval have been performed to obtain an estimation of the quantitative uncertainty caused by the mismatching, and quantitative errors of up to 6.3% have been measured. At present the method is probably most useful when groups of patients are studied.

A generic model for 11C labelled radiopharmaceuticals for imaging receptors in the human brain

A large number of radiopharmaceuticals labelled with 11C (half-time 0.340 h) are being developed for positron emission tomographic studies of different types of receptor in the human brain. For most of these agents, the available biokinetic data are insufficient to construct realistic compound-specific biokinetic models for calculating the internal radiation dose delivered to persons undergoing investigation. A generic model for brain receptor substances that predicts the internal dose with sufficient accuracy for general radiation protection purposes has, therefore, been developed. Biokinetic data for 13 11C-radiopharmaceuticals used clinically for imaging different brain receptors indicate that, despite differences in chemical structure, their uptake and retention in the human brain and other tissues are broadly similar. The proposed model assumes instantaneous deposition of 5% of the injected radioactivity in the brain, with the remaining radioactivity being rapidly and uniformly distributed throughout all other tissues. Elimination from all tissues is assumed to occur with a half-time of 2 h. It is further assumed that 75% of the injected 11C is excreted in the urine, and 25% via the gall bladder, with a half-time of 2 h. This model yields an effective dose of 4.5 x 10(-3) mSv MBq(-1), with doses of 3.2 x 10(-2), 1.7 x 10(-2), 8.7 x 10(-3), 5.2 x 10(-3), and 3.8 x 10(-3) mGy MBq(-1) to the urinary bladder, gall bladder, kidneys, brain and ovaries, respectively. These doses are well within the range of those reported using compound-specific models for the radiopharmaceutals studied.