The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes

BACKGROUND

Microalbuminuria and hypertension are risk factors for diabetic nephropathy. Blockade of the renin-angiotensin system slows the progression to diabetic nephropathy in patients with type 1 diabetes, but similar data are lacking for hypertensive patients with type 2 diabetes. We evaluated the renoprotective effect of the angiotensin-II-receptor antagonist irbesartan in hypertensive patients with type 2 diabetes and microalbuminuria.

METHODS

A total of 590 hypertensive patients with type 2 diabetes and microalbuminuria were enrolled in this multinational, randomized, double-blind, placebo-controlled study of irbesartan, at a dose of either 150 mg daily or 300 mg daily, and were followed for two years. The primary outcome was the time to the onset of diabetic nephropathy, defined by persistent albuminuria in overnight specimens, with a urinary albumin excretion rate that was greater than 200 microg per minute and at least 30 percent higher than the base-line level.

RESULTS

The base-line characteristics in the three groups were similar. Ten of the 194 patients in the 300-mg group (5.2 percent) and 19 of the 195 patients in the 150-mg group (9.7 percent) reached the primary end point, as compared with 30 of the 201 patients in the placebo group (14.9 percent) (hazard ratios, 0.30 [95 percent confidence interval, 0.14 to 0.61; P< 0.001] and 0.61 [95 percent confidence interval, 0.34 to 1.08; P=0.081 for the two irbesartan groups, respectively). The average blood pressure during the course of the study was 144/83 mm Hg in the placebo group, 143/83 mm Hg in the 150-mg group, and 141/83 mm Hg in the 300-mg group (P=0.004 for the comparison of systolic blood pressure between the placebo group and the combined irbesartan groups). Serious adverse events were less frequent among the patients treated with irbesartan (P=0.02).

CONCLUSIONS

Irbesartan is renoprotective independently of its blood-pressure-lowering effect in patients with type 2 diabetes and microalbuminuria.

Characterization of phosphoproteins from electrophoretic gels by nanoscale Fe(III) affinity chromatography with off-line mass spectrometry analysis

Detailed characterization of phosphoproteins as well as other post-translationally modified proteins is required to fully understand protein function and regulatory events in cells and organisms. Here we present a mass spectrometry (MS) based experimental strategy for the identification and mapping of phosphorylation site(s) using only low-picomole amounts of phosphoprotein starting material. Miniaturized sample preparation methods for MS facilitated localization of phosphorylation sites in phosphoproteins isolated by polyacrylamide gel electrophoresis. Custom made, nanoscale immobilized Fe(III) affinity chromatography (Fe(III)-IMAC) columns were employed for enrichment of phosphorylated peptides from crude peptide mixtures prior to off-line analysis by matrix-assisted laser desorption/ionization (MALDI) MS or nanoelectrospray tandem mass spectrometry (MS/MS). An optimized and sensitive procedure for alkaline phosphatase treatment of peptide mixtures was implemented, which in combination with nano-scale Fe(III)-IMAC and MALDI-MS allowed unambiguous identification of phosphopeptides by observation of 80 Da mass shifts. Nanoelectrospray MS/MS was used for phosphopeptide sequencing for exact determination of phosphorylation sites. The advantages and limitations of the experimental strategy was demonstrated by enrichment, identification and sequencing of phosphopeptides from the model proteins ovalbumin and bovine beta-casein isolated by gel electrophoresis. Furthermore, an autophosphorylation site at Ser-3 in recombinant human casein kinase-2 beta subunit was determined. The potential of miniaturized Fe(III)-IMAC and MALDI-MS for characterization of in vivo phosphorylated proteins was demonstrated by identification of tryptic phosphopeptides derived from the human p47/phox phosphoprotein isolated by two-dimensional gel electrophoresis.

Uracil-DNA glycosylase (UNG)-deficient mice reveal a primary role of the enzyme during DNA replication

Gene-targeted knockout mice have been generated lacking the major uracil-DNA glycosylase, UNG. In contrast to ung- mutants of bacteria and yeast, such mice do not exhibit a greatly increased spontaneous mutation frequency. However, there is only slow removal of uracil from misincorporated dUMP in isolated ung-/- nuclei and an elevated steady-state level of uracil in DNA in dividing ung-/- cells. A backup uracil-excising activity in tissue extracts from ung null mice, with properties indistinguishable from the mammalian SMUG1 DNA glycosylase, may account for the repair of premutagenic U:G mispairs resulting from cytosine deamination in vivo. The nuclear UNG protein has apparently evolved a specialized role in mammalian cells counteracting U:A base pairs formed by use of dUTP during DNA synthesis.

Feature-selective attention enhances color signals in early visual areas of the human brain

We used an electrophysiological measure of selective stimulus processing (the steady-state visual evoked potential, SSVEP) to investigate feature-specific attention to color cues. Subjects viewed a display consisting of spatially intermingled red and blue dots that continually shifted their positions at random. The red and blue dots flickered at different frequencies and thereby elicited distinguishable SSVEP signals in the visual cortex. Paying attention selectively to either the red or blue dot population produced an enhanced amplitude of its frequency-tagged SSVEP, which was localized by source modeling to early levels of the visual cortex. A control experiment showed that this selection was based on color rather than flicker frequency cues. This signal amplification of attended color items provides an empirical basis for the rapid identification of feature conjunctions during visual search, as proposed by "guided search" models.

Diagnosing intramammary infections: evaluation of definitions based on a single milk sample

Criteria for diagnosing intramammary infections (IMI) have been debated for many years. Factors that may be considered in making a diagnosis include the organism of interest being found on culture, the number of colonies isolated, whether or not the organism was recovered in pure or mixed culture, and whether or not concurrent evidence of inflammation existed (often measured by somatic cell count). However, research using these criteria has been hampered by the lack of a "gold standard" test (i.e., a perfect test against which the criteria can be evaluated) and the need for very large data sets of culture results to have sufficient numbers of quarters with infections with a variety of organisms. This manuscript used 2 large data sets of culture results to evaluate several definitions (sets of criteria) for classifying a quarter as having, or not having an IMI by comparing the results from a single culture to a gold standard diagnosis based on a set of 3 milk samples. The first consisted of 38,376 milk samples from which 25,886 triplicate sets of milk samples taken 1 wk apart were extracted. The second consisted of 784 quarters that were classified as infected or not based on a set of 3 milk samples collected at 2-d intervals. From these quarters, a total of 3,136 additional samples were evaluated. A total of 12 definitions (named A to L) based on combinations of the number of colonies isolated, whether or not the organism was recovered in pure or mixed culture, and the somatic cell count were evaluated for each organism (or group of organisms) with sufficient data. The sensitivity (ability of a definition to detect IMI) and the specificity (Sp; ability of a definition to correctly classify noninfected quarters) were both computed. For all species, except Staphylococcus aureus, the sensitivity of all definitions was <90% (and in many cases<50%). Consequently, if identifying as many existing infections as possible is important, then the criteria for considering a quarter positive should be a single colony (from a 0.01-mL milk sample) isolated (definition A). With the exception of "any organism" and coagulase-negative staphylococci, all Sp estimates were over 94% in the daily data and over 97% in the weekly data, suggesting that for most species, definition A may be acceptable. For coagulase-negative staphylococci, definitions B (2 colonies from a 0.01-mL milk sample) raised the Sp to 92 and 95% in the daily and weekly data, respectively. For "any organism," using definition B raised the Sp to 88 and 93% in the 2 data sets, respectively. The final choice of definition will depend on the objectives of study or control program for which the sample was collected.

Renoprotective effects of angiotensin II receptor blockade in type 1 diabetic patients with diabetic nephropathy

BACKGROUND

Angiotensin I-converting enzyme (ACE) inhibitors reduce angiotensin II formation and induce bradykinin accumulation. Animal studies suggest that bradykinin may play a role for the effects of ACE inhibition on blood pressure and kidney function. Therefore, we compared the renal and hemodynamic effects of specific intervention in the renin-angiotensin system by blockade of the angiotensin II subtype-1 receptor to the effect of ACE inhibition.

METHODS

A randomized, double-blind, cross-over trial was performed in 16 type 1 diabetic patients (10 men), age 42 +/- 2 years (mean +/- SEM). The study consisted of five periods, each lasting two months. The patients received losartan 50 mg, losartan 100 mg, enalapril 10 mg, enalapril 20 mg, and placebo in random order. At the end of each period, albuminuria, 24-hour blood pressure, and glomerular filtration rate (GFR) were determined.

RESULTS

Both doses of losartan and enalapril reduced albuminuria (P < 0.05) and mean arterial blood pressure (MABP; P < 0.05), whereas GFR remained stable. Albuminuria was reduced by 33% (95% CI, 12 to 51) on losartan 50 mg, 44% (95% CI, 26 to 57) on losartan 100 mg, 45% (95% CI, 23 to 61) on enalapril 10 mg, and 59% (95% CI, 39 to 72) on enalapril 20 mg, and MABP fell by 9 +/- 2, 8 +/- 2, 6 +/- 3, and 11 +/- 3 mm Hg (mean +/- SEM), respectively. No significant differences were found between the effects of losartan 100 mg and enalapril 20 mg. HbA1C and sodium intake remained unchanged throughout the study, whereas a significant rise in serum potassium occurred during ACE inhibition.

CONCLUSION

The angiotensin II subtype 1 receptor antagonist, losartan, reduces albuminuria and MABP similar to the effect of ACE inhibition. These results indicate that the reduction in albuminuria and blood pressure during ACE inhibition is primarily caused by interference in the renin-angiotensin system. Our study suggest that losartan represents a valuable new drug in the treatment of hypertension and proteinuria in type 1 diabetic patients with diabetic nephropathy.

Environmental iodine intake affects the type of nonmalignant thyroid disease

The relationship between the iodine intake level of a population and the occurrence of thyroid diseases is U-shaped with an increase in risk from both low and high iodine intakes. Developmental brain disorders and endemic goiter caused by severe iodine deficiency may seriously deteriorate overall health status and economic performance of a population. Severe iodine deficiency with a median 24-hour urinary iodine excretion of the population below 25 microg needs immediate attention and correction. Less severe iodine deficiency with median urinary iodine excretion below 120 microg per 24 hours is associated with multinodular autonomous growth and function of the thyroid gland leading to goiter and hyperthyroidism in middle aged and elderly subjects. The lower the iodine intake, the earlier and more prominent are the abnormalities. At the other end of the spectrum, severely excessive iodine intake starting at median urinary iodine excretion levels around 800 microg per 24 hours is associated with a higher prevalence of thyroid hypofunction and goiter in children. A number of studies indicate that moderate and mild iodine excess (median urinary iodine >220 microg per 24 hours) are associated with a more frequent occurrence of hypothyroidism, especially in elderly subjects. The exact mechanism leading to this has not been clarified, and more studies are needed to define the limits of excessive iodine intake precisely. Due to the frequent occurrence of thyroid disorders, proper monitoring and control of the population iodine intake level is a cost-effective alternative to diagnosing, therapy and control of the many individual cases of thyroid diseases that might have been prevented.

Ketobemidone, methadone and pethidine are non-competitive N-methyl-D-aspartate (NMDA) antagonists in the rat cortex and spinal cord

The opiate agonists, ketobemidone, methadone and pethidine, were evaluated as N-methyl-D-aspartate (NMDA) receptor antagonists using the rat cortical wedge preparation and the neonatal rat spinal cord preparation for electrophysiological studies and [3H](RS)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-im ine ([3H]MK-801) binding experiments using rat forebrain homogenates. Ketobemidone, methadone and pethidine were inhibitors of [3H]MK-801 binding with Ki values of 26 microM, 0.85 microM and 47 microM, respectively. In the cortex, 1 mM ketobemidone and 1 mM methadone reduced NMDA responses, but not (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid (AMPA) or kainate responses in an use-dependent manner, whereas 1 mM pethidine was devoid of antagonist activity. In the spinal cord preparation, the activities of ketobemidone and methadone were weaker than in cortex. In contrast, pethidine was equipotent with ketobemidone in the spinal cord. These results suggest that ketobemidone and methadone may be useful therapeutic agents in conditions where a combined opiate agonist and NMDA antagonist treatment is desired.

Aldosterone escape during blockade of the renin-angiotensin-aldosterone system in diabetic nephropathy is associated with enhanced decline in glomerular filtration rate

AIMS/HYPOTHESIS

It has been suggested that aldosterone plays a role in the initiation and progression of renal disease independently of arterial blood pressure and plasma angiotensin II levels. We evaluated the influence of plasma aldosterone levels on progression of diabetic nephropathy during long-term blockade of the renin-angiotensin-aldosterone system.

METHODS

A total of 63 hypertensive patients with type 1 diabetes and diabetic nephropathy were treated with losartan, 100 mg once daily, for a mean follow-up period of 35 months. Plasma aldosterone, GFR, albuminuria and 24-h blood pressure were determined at baseline and at regular intervals during the study.

RESULTS

Patients were divided according to their increasing or decreasing levels of plasma aldosterone during long-term losartan treatment in an escape group (n=26) and a non-escape group (n=37). In the escape group, aldosterone levels increased from (geometric mean [95% CI]) 57 pg/ml (43-76 pg/ml) at 2 months, to 102 pg/ml (78-134 pg/ml) at the end of the study (p<0.01). The corresponding levels in the non-escape group were 83 pg/ml (69-102 pg/ml) and 49 pg/ml (40-60 pg/ml; p<0.01). The median rate of decline in GFR was 5.0 ml.min(-1).year(-1) (range 0.4-15.9 ml.min(-1).year(-1)) in the escape group, compared with 2.4 ml.min(-1).year(-1) (-1.6 to 11.0 ml.min(-1).year(-1)) in the non-escape group (p<0.005). The increase in plasma aldosterone correlated with the rate of decline in GFR (r(2)=0.19, p<0.001), corresponding to a decline in GFR of 1.5 ml.min(-1).year(-1) for every two-fold increase in plasma aldosterone. Pre-treatment and treatment values of plasma aldosterone were not related to albuminuria or to changes in albuminuria during the study.

CONCLUSIONS/INTERPRETATION

Our data suggest that aldosterone escape during long-term blockade of the renin-angiotensin-aldosterone system is associated with an enhanced decline in GFR in patients with type 1 diabetes and diabetic nephropathy.

Strategies for clinical implementation of TNM-Immunoscore in resected nonsmall-cell lung cancer

Immunoscore is a prognostic tool defined to quantify in situ immune cell infiltrates and appears highly promising as a supplement to the tumor-node-metastasis (TNM) classification of various tumors. In colorectal cancer, an international task force has initiated prospective multicenter studies aiming to implement TNM-Immunoscore (TNM-I) in a routine clinical setting. In breast cancer, recommendations for the evaluation of tumor-infiltrating lymphocytes (TILs) have been proposed by an international working group. Regardless of promising results, there are potential obstacles related to implementing TNM-I into the clinic. Diverse methods may be needed for different malignancies and even within each cancer entity. Nevertheless, a uniform approach across malignancies would be advantageous. In nonsmall-cell lung cancer (NSCLC), there are several previous reports indicating an apparent prognostic importance of TILs, but studies on TILs in a TNM-I setting are sparse and no general recommendations are made. However, recently published data is promising, evoking a realistic hope of a clinical useful NSCLC TNM-I. This review will focus on the TNM-I potential in NSCLC and propose strategies for clinical implementation of a TNM-I in resected NSCLC.

Opioid analgesics as noncompetitive N-methyl-D-aspartate (NMDA) antagonists

Much evidence points to the involvement of N-methyl-D-aspartate (NMDA) receptors in the development and maintainance of neuropathic pain. In neuropathic pain, there is generally involved a presumed opioid-insensitive component, which apparently can be blocked by NMDA receptor antagonists. However, in order to obtain complete analgesia, a combination of an NMDA receptor antagonist and an opioid receptor agonist is needed. Recent in vitro data have demonstrated that methadone, ketobemidone, and dextropropoxyphene, in addition to being opioid receptor agonists, also are weak noncompetitive NMDA receptor antagonists. Clinical anecdotes suggest that the NMDA receptor antagonism of these opioids may play a significant role in the pharmacological action of these compounds; however, no clinical studies have been conducted to support this issue. In the present commentary, we discuss evidence for the NMDA receptor antagonism of these compounds and its relevance for clinical pain treatment; an overview of structure-activity relationships for the relevant opioids as noncompetitive NMDA receptor antagonists also is given. It is concluded that although the finding that some opioids are weak noncompetitive NMDA receptor antagonists in vitro has created much attention among clinicians, no clinical studies have been conducted to evaluate the applicability of these compounds in the treatment of neuropathic pain conditions.

Localization of nonpancreatic secretory phospholipase A2 in normal and atherosclerotic arteries. Activity of the isolated enzyme on low-density lipoproteins

Secretory nonpancreatic type II phospholipase A2 (snpPLA2) hydrolyzes fatty acids at the sn-2 position in phospholipids releasing free fatty acids (FFAs) and lysophospholipids. These products may act as intracellular second messengers or can be further metabolized into proinflammatory lipid mediators. The presence of snpPLA2 in extracellular fluids and serum during inflammation has suggested a role of the enzyme in this process. However, the presence of snpPLA2 in a variety of normal tissues suggests that snpPLA2 may also have physiological functions. Atherosclerosis appears to have an inflammatory component. Here we report on the snpPLA2 localization in normal and atherosclerotic lesions and on the properties of the isolated enzyme. A strong snpPLA2 immunoreactivity was observed in the arterial media that was colocalized with alpha-actin-positive vascular smooth muscle cells (SMCs) in both normal and atherosclerotic vessels. In aortic atherosclerotic lesions, snpPLA2 was observed colocalized with CD68-positive macrophages and HHF-35-positive SMCs and extracellularly in the lipid core. snpPLA2 was isolated from human normal arteries and from aorta with lesions. The enzyme was isolated by acid extraction of normal arterial tissues followed by immunoaffinity chromatography. The purified snpPLA2 had an expected molecular weight of 14 kD by polyacrylamide gel electrophoresis and appeared as a single band in immunoblotting. The enzymatic activity was followed by measuring release of fatty acids from phospholipid liposomes or LDL as substrates. The enzymatic activity was inhibited with two specific inhibitors for human snpPLA2: (1) monoclonal antibody 187 and (2) LY311727, a synthetic selective inhibitor. The mRNA for snpPLA2 was detected with reverse transcriptase polymerase chain reaction. These results indicate that snpPLA2 is present in human arteries and that it is able to hydrolyze phospholipids in LDL. The results support the hypothesis that snpPLA2 can release proinflammatory lipids at places of LDL deposition in the arterial wall.

Pro- and anti-angiogenic factors in human skeletal muscle in response to acute exercise and training

This study examined the effect of acute exercise and 4 weeks of aerobic training on skeletal muscle gene and protein expression of pro- and anti-angiogenic factors in 14 young male subjects. Training consisted of 60 min of cycling (∼60% of ), 3 times/week. Biopsies were obtained from vastus lateralis muscle before and after training. Muscle interstitial fluid was collected during cycling at weeks 0 and 4. Training increased (P < 0.05) the capillary: fibre ratio and capillary density by 23% and 12%, respectively. The concentration of interstitial vascular endothelial growth factor (VEGF) in response to acute exercise increased similarly (>6-fold; P < 0.05) before and after training. Resting protein levels of soluble VEGF receptor-1 in interstitial fluid, and of VEGF, thrombospondin-1 (TSP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP1) in muscle were unaffected by training, whereas endothelial nitric oxide synthase protein levels in muscle increased by 50% (P < 0.05). Before and after training, acute exercise induced a similar increase (P < 0.05) in the mRNA level of angiopoietin 2, matrix metalloproteinase 9 and TSP-1. After training, TIMP1 mRNA content increased with exercise (P < 0.05). In conclusion, acute exercise induced a similar increase in the gene-expression of both pro- and anti-angiogenic factors in untrained and trained muscle. We propose that the increase in anti-angiogenic factors with exercise is important for modulation of angiogenesis. The lack of effect of training on basal muscle VEGF protein levels and VEGF secretion during exercise suggests that increased VEGF levels are not a prerequisite for exercise-induced capillary growth in healthy muscle.

Effect of time interval between breast-conserving surgery and radiation therapy on ipsilateral breast recurrence

PURPOSE

To examine the effect of the time interval (interval) between breast-conserving surgery (BCS) and the start of radiation therapy (RT) on the subsequent risk of ipsilateral breast cancer recurrence (IBR).

METHODS AND MATERIALS

We reviewed interval and a number of prognostic and treatment factors among 1,962 women treated with BCS and RT for invasive breast cancer diagnosed between January 1, 1989 and December 31, 1993 in British Columbia, Canada. Subjects were female, less than 90 years old at diagnosis, not treated with chemotherapy, not stage T4 or M1, and had survived more than 30 days from diagnosis. The cumulative incidence of IBR was estimated in four interval groups: 0-5, 6-8, 9-12, and 13+ weeks. Only 23 women had an interval of greater than 20 weeks between BCS and start of RT. To assess whether an imbalance of prognostic and treatment factors could be obscuring real differences between the interval groups, Cox proportional hazards regression analyses were conducted.

RESULTS

Median follow-up was 71 months. The crude incidence of IBR for the entire sample was 3.9%. The cumulative incidence of IBR in the 6-8, 9-12, and 13+ week groups was not statistically significantly different from the cumulative incidence of IBR in the 0-5 week group. Multivariate analyses demonstrated that patients not using tamoxifen p = 0.027) and those with grade 3 histology (p = 0.003) were more likely to recur in the breast. Interval between BCS and RT was not a statistically significant predictor of breast recurrence when entered into a model incorporating tamoxifen use and tumor grade (0-5 vs. 6-8 weeks, p = 0.872; 0-5 vs. 9-12 weeks, p = 0.665; 0-5 vs. 13+ weeks, p = 0.573).

CONCLUSIONS

We found no univariate or multivariate difference in ipsilateral breast cancer recurrence between intervals of 0 to 20 weeks from breast conserving surgery to start of radiation therapy, in a population-based, low risk group of women not receiving adjuvant chemotherapy, after controlling for other factors important in predicting ipsilateral breast cancer recurrence.

Variations in urinary iodine excretion and thyroid function. A 1-year study in healthy men

OBJECTIVE

The iodine intake level in a population is determined in cross-sectional studies. A fraction of samples with iodine content below a certain level, e.g. 25 microg/l, may suggest iodine deficiency in part of the population. However, urinary iodine varies considerably from day to day and the fraction of low samples caused by dispersion remains unsettled.

DESIGN

A longitudinal study of 16 healthy men living in an area of mild to moderate iodine deficiency.

METHODS

We measured urinary iodine and creatinine concentrations, and serum TSH, total thyroxine (T4), free T4 index and total tri-iodothyronine (T3) in samples collected monthly for 1 year.

RESULTS

Average urinary iodine excretion was 57.0 microg/l (49.1 microg/24 h (corrected for creatinine excretion)) and varied from 29 to 81 microg/l (28 to 81 microg/24 h) between participants. Individual samples varied between 10 and 260 microg/l, and the variation around the mean was 2.4 times larger when calculated for the 180 individual samples compared with the 15 average annual values (1.7 times larger for estimated 24 h iodine excretion values). The fraction of individual samples below 25 microg/l was 6.7% (7.2% < 25 microg/24 h), whereas none of the participants had average iodine excretion below 25 microg/l or 25 microg/24 h. Participants with average annual iodine excretion below 50 microg/24 h had a negative correlation between iodine excretion and TSH, whereas a positive correlation was observed when average annual iodine excretion was above this level.

CONCLUSIONS

Seven per cent of individual urine samples indicated severe iodine deficiency without this being present in the group studied. Dispersion was reduced by 24% when using estimated 24 h urinary iodine excretion rather than urinary iodine concentration. Participants with moderate iodine deficiency (average annual urinary iodine excretion 25-50 microg/24 h) showed clear signs of substrate deficiency for thyroid hormone synthesis while participants with mild iodine deficiency (50-100 microg/24 h) did not.

Thyroid disorders in mild iodine deficiency

Comparative epidemiologic studies in areas with low and high iodine intake and controlled studies of iodine supplementation have demonstrated that the major consequence of mild-to-moderate iodine deficiency for the health of the population is an extraordinarily high occurrence of hyperthyroidism in elderly subjects, especially women, with risk of cardiac arrhythmias, osteoporosis, and muscle wasting. The hyperthyroidism is caused by autonomous nodular growth and function of the thyroid gland and it is accompanied by a high frequency of goiter. Pregnant women and small children are not immediately endangered but the consequences of severe iodine deficiency for brain development are grave and a considerable safety margin is advisable. Moreover, a shift toward less malignant types of thyroid cancer and a lower radiation dose to the thyroid in case of nuclear fallout support that mild-to-moderate iodine deficiency should be corrected. However, there is evidence that a high iodine intake may be associated with more autoimmune hypothyroidism, and that Graves' disease may manifest at a younger age and be more difficult to treat. Hence, the iodine intake should be brought to a level at which iodine deficiency disorders are avoided but not higher. Iodine supplementation programs should aim at relatively uniform iodine intake, avoiding deficient or excessive iodine intake in subpopulations. To adopt such a strategy, surveillance programs are needed.

Properties and functions of human uracil-DNA glycosylase from the UNG gene

The human UNG-gene at position 12q24.1 encodes nuclear (UNG2) and mitochondrial (UNG1) forms of uracil-DNA glycosylase using differentially regulated promoters, PA and PB, and alternative splicing to produce two proteins with unique N-terminal sorting sequences. PCNA and RPA co-localize with UNG2 in replication foci and interact with N-terminal sequences in UNG2. Mitochondrial UNG1 is processed to shorter forms by mitochondrial processing peptidase (MPP) and an unidentified mitochondrial protease. The common core catalytic domain in UNG1 and UNG2 contains a conserved DNA binding groove and a tight-fitting uracil-binding pocket that binds uracil only when the uracil-containing nucleotide is flipped out. Certain single amino acid substitutions in the active site of the enzyme generate DNA glycosylases that remove either thymine or cytosine. These enzymes induce cytotoxic and mutagenic abasic (AP) sites in the E. coli chromosome and were used to examine biological consequences of AP sites. It has been assumed that a major role of the UNG gene product(s) is to repair mutagenic U:G mispairs caused by cytosine deamination. However, one major role of UNG2 is to remove misincorporated dUMP residues. Thus, knockout mice deficient in Ung activity (Ung-/- mice) have only small increases in GC-->AT transition mutations, but Ung-/- cells are deficient in removal of misincorporated dUMP and accumulate approximately 2000 uracil residues per cell. We propose that BER is important both in the prevention of cancer and for preserving the integrity of germ cell DNA during evolution.

Multiple fatty acid binding to albumin in human blood plasma

Binding equilibria of long-chain fatty acids to human serum albumin, in serum or plasma, were studied by a dialysis exchange rate technique. Palmitate was added to citrated plasma in vitro and it was observed that between six and ten palmitate molecules were bound to albumin with nearly equal affinity. Observations in vivo gave similar results in the following series: (a) in two volunteers with increased fatty acid concentrations after fasting, exercise, and a cold shower: (b) in three male volunteers in whom high concentrations of non-esterified fatty acids, up to 4.6 mM, were induced by intravenous administration of a preparation of lecithin/glycocholate mixed micelles, and (c) in 81 patients with diabetes mellitus, type I. The binding pattern of palmitate in serum or plasma is essentially different from that observed with palmitate added to buffered solutions of pure albumin when two molecules are tightly bound and about four additional molecules with lower affinity. The differences may partly be explained by the presence of chloride ions in blood plasma, reducing the affinity for binding of the first two fatty acid molecules, and partly by facilitated binding of several molecules of mixed fatty acids, as found in plasma.

Prostate-specific membrane antigen: evidence for the existence of a second related human gene

Prostate-specific membrane antigen (PSM) is a glycoprotein recognised by the prostate-specific monoclonal antibody 7E11-C5, which was raised against the human prostatic carcinoma cell line LNCaP. A cDNA clone for PSM has been described. PSM is of clinical importance for a number of reasons. Radiolabelled antibody is being evaluated both as an imaging agent and as an immunotherapeutic in prostate cancer. Use of the PSM promoter has been advocated for gene therapy applications to drive prostate-specific gene expression. Although PSM is expressed in normal prostate as well as in primary and secondary prostatic carcinoma, different splice variants in malignant tissue afford the prospect of developing reverse transcription-polymerase chain reaction (RT-PCR)-based diagnostic screens for the presence of prostatic carcinoma cells in the circulation. We have undertaken characterisation of the gene for PSM in view of the protein's interesting characteristics. Unexpectedly, we have found that there are other sequences apparently related to PSM in the human genome and that PSM genomic clones map to two separate and distinct loci on human chromosome 11. Investigation of the function of putative PSM-related genes will be necessary to enable us to define fully the role of PSM itself in the development of prostatic carcinoma and in the clinical management of this malignancy.

Iodine in drinking water varies by more than 100-fold in Denmark. Importance for iodine content of infant formulas

The iodine intake level of the population is of major importance for the occurrence of thyroid disorders in an area. The aim of the present study was to evaluate the importance of drinking water iodine content for the known regional differences in iodine intake in Denmark and for the iodine content of infant formulas. Iodine in tap water obtained from 55 different locations in Denmark varied from <1.0 to 139 microg/l. In general the iodine content was low in Jutland (median 4.1 microg/l) with higher values on Sealand (23 microg/l) and other islands. Preparation of coffee or tea did not reduce the iodine content of tap water with a high initial iodine concentration. A statistically significant correlation was found between tap water iodine content today and the urinary iodine excretion measured in 41 towns in 1967 (r=0.68, P<0.001). The correlation corresponded to a basic urinary iodine excretion in Denmark of 43 microg/24h excluding iodine in water and a daily water intake of 1.7 l. The iodine content of infant formulas prepared by addition of demineralized water varied from 37 to 138 microg/l (median 57 microg/l, n=18). Hence the final iodine content would depend heavily on the source of water used for preparation. We found that iodine in tap water was a major determinant of regional differences in iodine intake in Denmark. Changes in water supply and possibly water purification methods may influence the population iodine intake level and the occurrence of thyroid disorders.

Elevated expression of human nonpancreatic phospholipase A2 in psoriatic tissue

In involved psoriatic tissue, which is characterized by chronic inflammation in both epidermis and dermis, elevated levels of arachidonic acid and eicosanoids have been measured. This implies that a phospholipase A2 (PLA2) may be involved in the pathogenesis of psoriasis. The PLA2's are a group of enzymes that release unsaturated fatty acids from the sn2-position of membrane phospholipids. Once released, the fatty acids are converted by various enzymes into biologically very important signaling molecules. Release of arachidonate initiates the arachidonate cascade, leading to the synthesis of eicosanoids such as prostaglandins, thromboxanes, leukotrienes, and lipoxines. Eicosanoids are important in a variety of physiological processes and play a central role in inflammatory mediators, such as lyso-PAF (a precursor for PAF) and other lysophospholipids, may also be formed through the action of a PLA2. We report for the first time the detection of transcripts of nonpancreatic phospholipase A2 (npPLA2, type II) and cytosolic (c) PLA2 in human skin, and overexpression of npPLA2 in involved skin from patients with psoriasis (plaque psoriasis and pustular psoriasis). Limited amounts of npPLA2 enzyme are detected immunologically in the uppermost layers of epidermis from healthy persons. Both involved and uninvolved psoriatic epidermis contain higher levels of npPLA2 than normal skin. Positive cells in dermis showed significantly higher levels of npPLA2 than epidermal cells. In dermis from healthy persons, only weak staining of a few cells could be detected. The two PLA2 enzymes detected in psoriatic skin (cytosolic and nonpancreatic) may both be involved in eicosanoid overproduction in psoriatic tissue, and the npPLA2 may also be involved in potentiating cell activation, especially T cells.

Phenotypic and genotypic characterization of phenanthrene-degrading fluorescent Pseudomonas biovars

A total of 41 phenanthrene degraders were isolated from a former coal gasification site by using Pseudomonas-selective Gould's S1 medium. All isolates were found to belong to the fluorescent Pseudomonas group and were subjected to characterization by phenotypic methods, including classical taxonomic tests, API 20NE, and Biolog GN, and the strains were further characterized by the genotypic method repetitive extragenic palindromic PCR (REP-PCR). By using classical tests, the population was found to consist of 38 strains belonging to P. fluorescens, 2 P. putida strains, and 1 Pseudomonas sp. Bacteria in phenograms from Biolog GN and REP-PCR data were divided into groups, which were in good agreement with classical test and API 20NE results. We found a nonfluorescent group of 22 bacteria inconsistent with any Pseudomonas sp. in Bergey's Manual of Systematic Bacteriology. The group showed small differences in the genotypic test, indicating that all 22 isolates were not recent clones of the same isolate. Analyses of the nonfluorescent group indicated that it belonged to Pseudomonas, but the group could not be affiliated with P. fluorescens because of differences in DNA-DNA hybridization. Identifications using classical tests and API 20NE were found to correlate, but Biolog GN identifications after 24-h incubation resulted very often in the distantly related P. corrugata. The reproducibilities of individual tests of each phenotypic method were assessed, and low reproducibilities were mainly found to be associated with specific Biolog GN test wells. Classical tests and API 20NE proved to be the best for identification of isolates, whereas Biolog GN and REP-PCR were found to be the best tests for high resolution among these closely related isolates.

Hearing by eye: how much spatial degradation can be tolerated?

In the McGurk effect (McGurk and MacDonald, 1976 Nature 264 746-748), illusory auditory perception is produced if the visual information from lip movements is discrepant from the auditory information from the voice. A study is reported of the tolerance of the effect to varying levels of spatial degradation (videotaped images of a speaker's face were quantised by a mosaic transform). The illusory effect systematically decreased with an increase in the coarseness of the spatial quantisation. However, even with the coarsest level (11.2 pixels/face) the illusion did not completely disappear. In addition, those participants who did not experience the illusion nevertheless showed the effects of auditory-visual interaction in their clarity ratings of the auditory stimulus. It is concluded that auditory-visual interaction in visible speech perception is based on relatively coarse-spatial-scale information.