Elements in autopsy liver tissue samples from Greenlandic inuit and Danes. V. Selenium measured by X-ray fluorescence spectrometry

The content of selenium in normal liver tissue samples from Greenlandic Inuit was measured and the results compared with those obtained in normal liver tissue samples from Danes. Normal liver tissue samples were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 23–83) and from 74 Danes (44 men, 30 women) with a median age of 60 years (range 15–87). Total liver selenium content was measured by X-ray fluorescence spectrometry. The content of selenium (median) was in Inuit 26.6 mol/kg dry liver (5–95 percentile: 15.2–49.4) and in Danes 17.7 mol/kg dry liver (5–95 percentile: < 3.8–36.5) (p < 0.0001). Liver selenium content displayed no significant gender difference, either in Inuit or Danes. In Inuit men, there was a negative correlation between liver selenium content and age (r_s = −0.39, p < 0.05), whereas Danish men displayed a positive correlation between liver selenium content and age (r_s = 0.37, p = 0.02). There was no correlation in Inuit or Danish women. In Inuit, the median hepatic selenium index (liver selenium content divided by age) was 0.48 and in Danes 0.33 (p = 0.001). There was an inverse correlation between hepatic selenium index and age both in Inuit (r_s = −0.77, p < 0.0001) and in Danes (r_s = −0.47, p < 0.0001). In conclusion, Inuit had a higher liver content of selenium and a higher hepatic selenium index compared with Danes. The more favourable selenium status is due to a higher nutritional selenium intake with fish and meat from sea mammals.     

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. II. Iron measured by X-ray fluorescence spectrometry.

The purpose of this study was to measure the content of iron (Fe) in liver tissue samples from urbanized Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in liver tissue samples from urbanized Danes. Normal liver tissue samples were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 23-83) and from 72 Danes (42 men, 30 women) with a median age of 62 years (range 15-87). In the entire series, there was no significant difference between liver iron in Inuit compared with Danes. Likewise, there was no significant gender difference concerning liver iron content, either in Inuit or in Danes. The median iron content (with 5-95 percentile) in Inuit was 17.23 mmol/kg dry liver (5.80-91.80) and in Danes 16.51 mmol/kg dry liver (7.83-39.05). However, when stratified according to age, a trend was revealed showing that Inuit men and women < or = 50 years had a lower liver iron content than Danes (p = 0.05 and p = 0.08) whereas Inuit men and women > 50 years had a higher liver iron content than Danes (p = 0.18 and p = 0.02). There was a significant correlation between liver iron content and age in both Inuit men (rs = 0.49, p = 0.01) and in women (rs = 0.64, p = 0.003), but not in Danes. In Inuit, the median hepatic iron index (liver iron content divided by age) was 0.33 in men and 0.32 in women. The median estimated iron content in the whole liver was 6.54 mmol (365 mg) in Inuit men and 5.41 mmol (302 mg) in Inuit women (p = 0.6). There was no correlation between hepatic iron index and age. In Danes, the median hepatic iron index was 0.46 in men and 0.29 in women (p = 0.01). There was a significant inverse correlation between hepatic iron index and age in the two genders and in the entire series (rs = -0.71, p = 0.0001). The results indicate that young and middle-aged urbanized Inuit have slightly smaller iron stores than urbanized Danes, whereas elderly Inuit have higher iron stores than Danes. In Danes, iron stores plateau at 30 to 40 years of age in men and some years after the menopause in women. In Inuit, iron stores continue to increase in old age, probably to due a lifelong dietary intake of haem iron.     

Cadmium, copper and zinc in tissues of deceased copper smelter workers

Workers at a copper and lead smelter in northern Sweden have a multifactorial exposure to a number of heavy metals. The concentrations of cadmium, copper and zinc in liver, lung, kidney and brain tissues have been determined by atomic absorption spectrometry in 32 deceased long-term exposed male lead smelter workers, and compared with those of 10 male controls. Furthermore, copper and zinc levels in hair and nails were determined by energy-dispersive X-ray fluorescence.

The highest cadmium concentrations among both workers and controls were observed in kidney, followed in order by liver, lung and brain. The levels in kidney, liver and lung were all significantly higher in the workers than in the controls (p < 0.03). Among the workers relatively strong positive correlations (p < 0.03) were observed between cadmium concentrations in liver and lung, liver and kidney, liver and brain, and lung and brain. In the exposed workers a positive correlation was observed between cadmium and zinc concentrations in the kidney (r_s = 0.38; p = 0.034). This is probably mainly due to the protein metallothionein, which is stored in the kidney, binding equimolar amounts of these two metals.

The highest concentrations of copper were found in hair and nails among both workers and controls, followed in order by liver, brain, kidney and lung. The tissue concentrations of copper in brain, lung and kidney were all significantly higher among the smelter workers than in the controls (p ≤ 0.036). Copper levels in lung and age at time of death were positively correlated among the exposed workers (r_s = 0.39; p = 0.029). In the same group, positive correlations between copper and zinc concentrations in kidney (r_s = 0.45; p = 0.009) and nails (r_s = 0.68; p < 0.001) were also observed, reflecting possible biological interactions between these two metals.

Among both workers and controls, the highest zinc concentrations were found in hair, followed in order by nails, liver, kidney, brain and lung. Significantly higher tissue concentrations among the workers as compared with the reference group were noted in kidney, liver and brain (p ≤ 0.033).

Neither copper nor zinc concentrations in hair and nails seemed to provide a useful measure of the trace element status of the smelter workers.     

The association between content of the elements S,Cl, K,Fe, Cu,Zn and Br in normal and cirrhotic liver tissue from Danes and Greenlandic Inuit examined by dual hierarchical clustering analysis

ProjectMeta-analysis of previous studies evaluating associations between content of elements sulphur (S), chlorine (Cl), potassium (K), iron (Fe), copper (Cu), zinc (Zn) and bromine (Br) in normal and cirrhotic autopsy liver tissue samples.ProcedureNormal liver samples from 45 Greenlandic Inuit, median age 60 years and from 71 Danes, median age 61 years. Cirrhotic liver samples from 27 Danes, median age 71 years. Element content was measured using X-ray fluorescence spectrometry. Statistics: Dual hierarchical clustering analysis, creating a dual dendrogram, one clustering element contents according to calculated similarities, one clustering elements according to correlation coefficients between the element contents, both using Euclidian distance and Ward Procedure.ResultsOne dendrogram separated subjects in 7 clusters showing no differences in ethnicity, gender or age. The analysis discriminated between elements in normal and cirrhotic livers. The other dendrogram clustered elements in four clusters: sulphur and chlorine; copper and bromine; potassium and zinc; iron. There were significant correlations between the elements in normal liver samples: S was associated with Cl, K, Br and Zn; Cl with S and Br; K with S, Br and Zn; Cu with Br. Zn with S and K. Br with S, Cl, K and Cu. Fe did not show significant associations with any other element.ConclusionsIn contrast to simple statistical methods, which analyses content of elements separately one by one, dual hierarchical clustering analysis incorporates all elements at the same time and can be used to examine the linkage and interplay between multiple elements in tissue samples.     

Differences in apolipoprotein(a) polymorphism in West Greenland Eskimos and Caucasian Danes

Summary Previous studies in Greenland suggest that death rates from ischemic heart disease [IHD] are lower in Eskimos than in Danes and other Caucasian populations. This has been explained by a high intake of n-3 polyunsaturated fatty acids with beneficial effects on blood lipids and hemostasis. In other populations, lipoprotein(a) [Lp(a)] is associated with IHD, plasma concentrations of Lp(a) being genetically determined to a major extent. We have compared Lp(a) concentrations and apo(a) phenotypes in 120 Greenlandic Eskimos with those in 466 Danish men. The median Lp(a) concentration in Eskimos (8.7mg/dl;[95% CI 6.5–10.7]) was not significantly different from that in Danes (6.3mg/dl; [95% CI 5.2–7.0]), whereas the 90th percentile was significantly higher among Danes: 46.36mg/dl; [95% Cl 43.0–54.3] vs. 27.6mg/dl [95% CI 20.7–36.9]. In 20% of the Danes, but in only 8% of the Eskimos (P = 0.009), the concentration of Lp(a) exceeded 30mg/dl. The difference is probably explained by a low frequency of the low molecular weight apo(a) phenotypes among Eskimos, since the apo(a) isoforms F and B were absent, and the S1 and S2 types were present in only 3.3% of Eskimos. In contrast, these apo(a) isoforms were present in 26.6% of the Danes in either single-band or double-band phenotypes. The pattern of apo(a) polymorphism found in this study could provide part of a genetic explanation for the putative low rates of IHD in Eskimo populations.     

The effect of gender and age on growth hormone replacement in growth hormone-deficient patients.

We analyzed the effect of growth hormone replacement therapy (36 months) analyzed at a dose adjusted to maintain serum insulin-like growth factor-I level between the median and the upper end of the age-related reference range on bone mineral density, body composition, and carbohydrate metabolism with respect to gender and age in 20 adult patients (9 women, 11 men, mean age: 43 years, range: 21-61 years). The lumbar and femoral T-score was increased after 12 and after 18 months of therapy respectively in men (p < 0.001 and p = 0.002), but did not changed significantly in women. The increase of femoral T-score was greater in young men (< or = 45 years, n = 6) than old men (> 45 years, n = 5, p < 0.001). Body fat was lower in men than in women after 6 months (p = 0.002). The waist/hip ratio only decreased in women (p = 0.044). The waist circumference decreased in both genders after 6 months of therapy (p < 0.001), but more markedly in females than in males (p < 0.05). The sum of skinfold thicknesses was reduced in males after 6 months of therapy (p < 0.001). Changes in body composition parameters measured were independent of age. The glycosylated hemoglobin increased without sex or age difference after 12 months of initiation of therapy (p < 0.001), but fasting glucose and insulin levels did not change during the therapy. Our results indicate that the effect of growth hormone replacement on bone mineral content in adults is age- and gender-dependent, gender dependent on body composition, but independent of age and gender on carbohydrate metabolism.     

Serum concentration of zinc, copper, manganese and magnesium in patients with liver cirrhosis

The role of trace elements in the pathogenesis of liver cirrhosis and its complications is still not clearly understood. Serum concentrations of zinc, copper, manganese and magnesium were determined in 105 patients with alcoholic liver cirrhosis and 50 healthy subjects by means of plasma sequential spectrophotometer. Serum concentrations of zinc were significantly lower (median 0.82 vs. 11.22 micromol/L, p < 0.001) in patients with liver cirrhosis in comparison to controls. Serum concentrations of copper were significantly higher in patients with liver cirrhosis (median 21.56 vs. 13.09 micromol/L, p < 0.001) as well as manganese (2.50 vs. 0.02 micromol/L, p < 0.001). The concentration of magnesium was not significantly different between patients with liver cirrhosis and controls (0.94 vs. 0.88 mmol/L, p = 0.132). There were no differences in the concentrations of zinc, copper, manganese and magnesium between male and female patients with liver cirrhosis. Only manganese concentration was significantly different between Child-Pugh groups (p = 0.036). Zinc concentration was significantly lower in patients with hepatic encephalopathy in comparison to cirrhotic patients without encephalopathy (0.54 vs. 0.96 micromol/L, p = 0.002). The correction of trace elements concentrations might have a beneficial effect on complications and maybe progression of liver cirrhosis. It would be recommendable to provide analysis of trace elements as a routine.     

Oxidative stress EPR measurement in human liver by radical-probe technique. Correlation with etiology,histology and cell proliferation

The role of reactive oxygen species (ROS) in liver disease is controversial. This mostly reflects the difficulties to quantify ROS in vivo, particularly in humans. We aimed to measure the presence of ROS in diseased human liver and identify possible relations between ROS levels and etiology, histology and hepatocyte proliferation. Liver biopsy specimens from 102 individuals: 18 healthy controls and 84 patients (42 HCV chronic hepatitis (CHC), 19 HBV chronic hepatitis (CHB), 7 PBC, 4 PSC, 4 HCV relapsing hepatitis after liver transplantation, 3 autoimmune hepatitis, 3 hepatocellular carcinoma, 2 alcoholic hepatitis) underwent analysis by radical-probe electron paramagnetic resonance (EPR). ROS in patients (median = 5 x 10(-6) mmol/mg) were higher than in controls (median = 3 x 10(-11) mmol/mg) (p < 0.001). Progressively increasing levels of ROS were recorded passing from control values to CHB (median = 4 x 10(-7) mmol/mg), CHC (median = 3 x 10(-6) mmol/mg) and PBC (median = 2 x 10(-5) mmol/mg), the differences being significant (p < 0.001). ROS in CHC positively correlated with histological disease activity (r = 0.92; p < 0.001). No correlation was found between ROS and hepatocyte proliferation rate, presence/degree of steatosis, serum ferritin levels and aminotransferases. ROS overproduction in liver appears to be a common thread linking different pathologic conditions and seems to be influenced by diseases' etiologies.     

The frontal sinus in ancient and modern Greenlandic Inuit

The purpose of this study was to compare the frontal sinus size of ancient Greenlandic Inuit with ancient Inuit of Alaska and Canada, and to compare sinus size between ancient and modern Greenlandic Inuit. Also, it was analyzed whether cranial size was a determinant of frontal sinus size. Frontal sinus size was evaluated in terms of absence frequency and planimetrically. Absence was defined as a frontal sinus not exceeding a line drawn between the supraorbital rims. A significant increase in absence frequency was noted from Alaska over Canada to Greenland (males: p<0.03; females p<0.0001). This is in accordance with earlier studies, indicating that although these Inuit populations once have been commonly related to the Old Bering Sea population, the Greenland Inuit represent an endpoint in an eastward migration. There was a significant increase (p<0.0001) in frontal sinus size from ancient to modern Greenlandic Inuit, probably indicative of a high degree of admixture with non-Inuit after modern colonization. The results regarding craniofacial size parameters and frontal sinus side were inconclusive. No single craniofacial variable showed significant effect on frontal sinus size, but the area displayed sexual dimorphism, females having smaller frontal sinuses.     

Thermal biology of the fossorial rodent Ctenomys fulvus from the Atacama desert, northern Chile

The Andean tuco-tuco, Ctenomys fulvus (Rodentia: Ctenomyidae) inhabits one of the most arid regions of the world, the Salar de Atacama, Northeast of Antofagasta, Chile (23°17′06″S, 68°05′43″W; 2.240 m.a.s.l). We found that a stable microclimate in burrows, a low evaporative water loss (EWL), and a diet of roots (59% water content) are the main factors that permit the survival of this fossorial species in harsh desert conditions. Large circadian variation in T_a was observed above ground. Daily ΔT_a (T_a max − T_a min) = 37.9±0.2°C in summer and in winter. In contrast, circadian variation of T_a inside the burrows was only 5.8±0.5°C in the same seasons. Relative humidity (RH) was 1.9–3.1% during the day, increasing to maximum values of 27% at night and early morning. Inside the burrows RH was higher and quite stable, ranging between 53.1 and 65%, independent of the time of day and season. EWL, measured between 10 and 25°C, was low (1.26 mg/g h), and a moderate increase of 13–20% was observed at higher temperatures. The low EWL may prevent dehydration. However, because of the low heat loss capability, animals became hyperthermic (0.8–1.6°C) in dry air at T_a=30–35°C. As T_a during afternoon normally exceeded 35°C, the microclimate of burrows provided the only way to avoid the lethal effects of hyperthermia.     

Increased content of zinc and iron in human cataractous lenses

The purpose of the study was to examine the zinc and iron content of human lenses in different types of cataract and to investigate the possible influence of diabetes on the zinc and iron content of the lens. Iron and zinc of 57 human lenses (28 corticonuclear cataracts and 29 mature cataracts with a mean age of 70.6±16.1 and 74.7±11.1 yr, 41 nondiabetics and 16 diabetics) were determined by atomic absorption spectroscopy. The zinc content of human lenses was significantly increased in mature cataracts compared to corticonuclear cataracts (0.51±0.33 vs 0.32±0.20 μmol/g dry mass, p=0.012). The iron content of mature cataracts was also higher than in corticonuclear cataracts (0.11±0.09 vs 0.07±0.05 μmol/g dry mass, p=0.071). Furthermore, a significant increase of the lens zinc content could be observed with increasing lens coloration (light brown 0.33±0.17 vs dark brown 0.52±0.35 μmol/g dry mass, p=0.032). Diabetic patients seem to have both increased zinc and iron contents in the lens compared to nondiabetic subjects (zinc: 0.45±0.42 vs 0.40±0.22 μmol/g dry mass; iron: 0.12±0.10 vs 0.08±0.05 μmol/g dry mass). These data suggest a possible influence of the lens zinc and iron content on the development of lens opacification. Especially advanced forms of cataract and dark brown colored lenses show significantly increased zinc and iron content.     

Oxidative Stress EPR Measurement in Human Liver by Radical-probe Technique. Correlation with Etiology,Histology and Cell Proliferation

The role of reactive oxygen species (ROS) in liver disease is controversial. This mostly reflects the difficulties to quantify ROS in vivo, particularly in humans. We aimed to measure the presence of ROS in diseased human liver and identify possible relations between ROS levels and etiology, histology and hepatocyte proliferation. Liver biopsy specimens from 102 individuals: 18 healthy controls and 84 patients (42 HCV chronic hepatitis (CHC), 19 HBV chronic hepatitis (CHB), 7 PBC, 4 PSC, 4 HCV relapsing hepatitis after liver transplantation, 3 autoimmune hepatitis, 3 hepatocellular carcinoma, 2 alcoholic hepatitis) underwent analysis by radical-probe electron paramagnetic resonance (EPR). ROS in patients (median=5 &#50 10 &#109 6 mmol/mg) were higher than in controls (median=3 &#50 10 &#109 11 mmol/mg) ( p <0.001). Progressively increasing levels of ROS were recorded passing from control values to CHB (median=4 &#50 10 &#109 7 mmol/mg), CHC (median=3 &#50 10 &#109 6 mmol/mg) and PBC (median=2 &#50 10 &#109 5 mmol/mg), the differences being significant ( p <0.001). ROS in CHC positively correlated with histological disease activity ( r =0.92; p <0.001). No correlation was found between ROS and hepatocyte proliferation rate, presence/degree of steatosis, serum ferritin levels and aminotransferases. ROS overproduction in liver appears to be a common thread linking different pathologic conditions and seems to be influenced by diseases' etiologies.     

Growth, nodulation and nitrate reductase activity in the aquatic legume Neptunia plena (L.) benth. At different external nitrate concentrations

The effects of different external nitrate concentrations (0 (control), 1, 50, 100, 500, 1000 and 20 000 mmol m⁻³) on growth, nodulation and nitrate-reductase activity (NRA) of inoculated Neptunia plena (L.) Benth. were examined.

Plants given 500 and 1000 mmol m⁻³ nitrate had greater (P < 0.05) shoot length, leaf, stem and root dry mass, and carbon and nitrogen contents than the controls and plants given 20 000 mmol m⁻³ nitrate. Nodule number was not significantly affected by nitrate concentration up to 50 mmol m⁻³, but 100 mmol m⁻³ nitrate reduced nodulation by 68% and concentrations above 100 mmol m⁻³ completely inhibited nodule development. Plants given 100–20000 mmol m⁻³ nitrate had a greater nitrate content per g leaf, stem and root dry mass (DM) than controls. Nitrate per g root DM did not increase with external nitrate concentration above 500 mmol m⁻³, but levels in leaf and stem were greater at 20 000 mmol m⁻³ nitrate than at all other concentrations. NRA per g leaf, stem and root fresh mass (FM) was greater for plants given 500–20000 mmol m⁻³ than for controls, but there was no significant increase with nitrate concentration above 500 mmol m⁻³. Substantial proportions of total plant nitrate and NRA were found in both root and shoot over the entire range of external nitrate concentrations given.

Findings for N. plena are compared with data obtained previously for terrestrial legumes.     

A numerical and experimental study of compliance and collapsibility of preterm lamb tracheae

Knowledge of the mechanical behaviour of immature tracheae is crucial in order to understand the effects exerted on central airways by ventilatory treatments, particularly of Total Liquid Ventilation. In this study, a combined experimental and computational approach was adopted to investigate the compliance and particularly collapsibility of preterm lamb tracheae in the range of pressure likely applied during Total Liquid Ventilation (−30 to 30 cmH₂O). Tracheal samples of preterm lambs (n=5; gestational age 120–130 days) were tested by altering transmural pressure from −30 to 30 cmH₂O. Inflation (S_i) and collapsing (S_c) compliance values were calculated in the ranges 0 to 10 cmH₂O and –10 to 0 cmH₂O, respectively. During the tests, an asymmetric behaviour of the ΔV/V₀ vs. P curves at positive and negative pressure was observed, with mean S_i=0.013 cmH₂O⁻¹ and S_c=0.053 cmH₂O⁻¹. A different deformed configuration of the sample regions was observed, depending on the posterior shape of cartilaginous ring. A three-dimensional finite-element structural model of a single tracheal ring, based on histology measurements of the tested samples was developed. The model was parameterised in order to represent rings belonging to three different tracheal regions (craniad, median, caudal) and numerical analyses replicating the collapse test conditions were performed to evaluate the ring collapsibility at pressures between 0 and −30 cmH₂O. Simulation results were compared to experimental data to verify the model's reliability. The best model predictions occurred at pressures −30 to −10 cmH₂O. In this range, a model composed of median rings best interpreted the experimental data, with a maximum error of 2.7%; a model composed of an equal combination of all rings yielded an error of 12.6%.     

Manganese(II) complexes of an acyclic phenol-based dinucleating ligand with four methoxyethyl chelating arms: synthesis, structure, magnetism and electrochemistry

Dinuclear manganese(II) complexes [Mn₂(bomp)(PhCO₂)₂]BPh₄ (1), [Mn₂(bomp)(MeCO₂)₂]BPh₄ (2), and [Mn₂(bomp)(PhCO₂)₂]PF₆ (3) were synthesized with a dinucleating ligand 2,6-bis[bis(2-methoxyethyl)aminomethyl]-4-methylphenol [H(bomp)]. Dinuclear zinc complex [Zn₂(bomp)(PhCO₂)₂]PF₆ (4) was also synthesized for the purpose of comparison. X-ray analysis revealed that the complex 1·CHCl₃ contains two manganese ions bridged by the phenolic oxygen and two benzoate groups, forming a μ-phenoxo-bis(μ-benzoato)dimanganese(II) core. Magnetic susceptibility measurements of 1–3 over the temperature range 1.8–300 K indicated antiferromagnetic interaction (J=−4 to −6 cm⁻¹). Cyclic voltammograms of 3 showed a quasi-reversible oxidation process at +0.9 V versus a saturated sodium chloride calomel reference electrode, assigned to Mn^IIMn^II/Mn^IIMn^III.     

Impact of maternal lifestyle factors on newborn HPRT mutant frequencies and molecular spectrum--initial results from the Prenatal Exposures and Preeclampsia Prevention (PEPP) Study

Epidemiological studies have demonstrated associations between maternal tobacco smoke exposure and consumption of alcohol during pregnancy and increased risk of pediatric malignancies, particularly infant leukemias. Molecular evidence also suggests that somatic mutational events occurring during fetal hematopoiesis in utero can contribute to this process. As part of an ongoing multi-endpoint biomarker study of 2000 mothers and newborns, the HPRT T-lymphocyte cloning assay was used to determine mutant frequencies (M_f) in umbilical cord blood samples from an initial group of 60 neonates born to a sociodemographically diverse cohort of mothers characterized with respect to age, ethnicity, socioeconomic status, and cigarette smoke and alcohol exposure. Non-zero M_f (N=47) ranged from 0.19 to 5.62×10⁻⁶, median 0.70×10⁻⁶, mean±SD 0.98±0.95×10⁻⁶. No significant difference in M_f was observed between female and male newborns. Multivariable Poisson regression analysis revealed that increased HPRT M_f were significantly associated with maternal consumption of alcohol at the beginning [Relative Rate (RR)=1.84, 95% CI=0.99–3.40, P=0.052) and during pregnancy (RR=2.99, 95% CI=1.14–7.84, P=0.026). No independent effect of self-reported active maternal cigarette smoking, either at the beginning or throughout pregnancy, nor maternal passive exposure to cigarette smoke was observed. Although based on limited initial data, this is the first report of a positive association between maternal alcohol consumption during pregnancy and HPRT M_f in human newborns. In addition, the spectrum of mutations at the HPRT locus was determined in 33 mutant clones derived from 19 newborns of mothers with no self-reported exposure to tobacco smoke and 14 newborns of mothers exposed passively or actively to cigarette smoke. In the unexposed group, alterations leading to specific exon 2–3 deletions, presumably as a result of illegitimate V(D)J recombinase activity, were found in five of the 19 mutants (26.3%); in the passively exposed group, two exon 2–3 deletions were present among the seven mutants (28.6%); and in the actively exposed group, six of the seven mutants (85.7%) were exon 2–3 deletions. Although no overall increase in HPRT M_f was observed and the number of mutant clones examined was small, these initial results point to an increase in V(D)J recombinase-associated HPRT gene exon 2–3 deletions in cord blood T-lymphocytes in newborns of actively smoking mothers relative to unexposed mothers (P=0.011). Together, these results add to growing molecular evidence that in utero exposures to genotoxicants result in detectable transplacental mutagenic effects in human newborns.     

Effect of oxygen transfer rate on β-carotene production from synthetic medium by Blakeslea trispora in shake flask culture

The effect of oxygen transfer rate (OTR) on β-carotene production by Blakelsea trispora in shake flask culture was investigated. The results indicated that the concentration of β-carotene (704.1 mg/l) was the highest in culture grown at maximum OTR of 20.5 mmol/(l h). In this case, the percentage of zygospores was over 50.0% of the biomass dry weight. On the other hand, OTR level higher than 20.5 mmol/(l h) was found to be detrimental to cell growth and pigment formation. To elucidate the effect of oxidative stress on β-carotene synthesis, the accumulation of hydrogen peroxide during fermentation under different OTRs was determined. A linear response of β-carotene synthesis to the level of H₂O₂ was observed, indicating that β-carotene synthesis is stimulated by H₂O₂. However, there was an optimal concentration of H₂O₂ (2400 μM) in enhancing β-carotene synthesis. At a higher concentration of H₂O₂, β-carotene decreased significantly due to its toxicity.     

Ethanol stimulates glycogenolysis in livers from fed rats.

To determine the reason for the lack of a hypoglycemic effect of ethanol in the fed state, the effect of ethanol on glucose turnover, liver glycogenolysis, and glucose metabolites was determined. Chronically catheterized awake and freely moving fed rats received either ethanol (blood ethanol, 37 +/- 10 mmol/liter, n = 11) or saline (n = 13) intravenously for 4 hr. Glucose turnover was determined using a primed continuous infusion of [3-3H]glucose. The liver was freeze clamped at 4 hr for glycogen and metabolite measurements. Plasma glucose (5.8 +/- 0.3 mmol/liter vs 6.3 +/- 0.2 mmol/liter at 4 hr, ethanol versus saline) and the rate of glucose turnover (61 +/- 9 vs 58 +/- 8 moles/kg.min) were similar during the ethanol and saline infusions. Plasma lactate was significantly higher in the ethanol (1.32 +/- 0.05 mmol/liter) than in the saline (0.86 +/- 0.06 mmol/liter, P less than 0.001) study. Concentrations of gluconeogenic intermediates in the liver (glucose 6-phosphate, fructose 6-phosphate, glucose 1-phosphate, and pyruvate) were all significantly and -30% lower in ethanol-infused than in saline-infused rats. The liver citrate content was similar in ethanol-infused than in saline-infused rats. The liver citrate content was similar in ethanol (0.38 +/- 0.03 mmol/liter) and saline (0.37 +/- 0.04 mmol/liter) studies. Liver glycogen was 75% lower in the ethanol-infused (61 +/- 9 mmol/kg dry wt) than the saline (242 +/- 27 mmol/kg dry wt, P less than 0.001)-infused rats. These data demonstrate that in fed rats given ethanol, glucose turnover is maintained constant by accelerated glycogenolysis. Thus, inhibition of gluconeogenesis by ethanol does not lower hepatic glucose production unless compensatory glycogenolysis can be prevented.     

Comparative determinations of low-density-lipoprotein-cholesterol.

Two different methods for low-density-lipoprotein-cholesterol (LDL-C) determination were comparatively used. The heparin-sodium citrate (pH 5.12) precipitation method gave similar LDL-C results to the ones given by the Friedewald et al. formula (3.2 vs 3.3 mmol/l) in 187 men. Values obtained using both methods show a very high and significant correlation (r > 0.9; p < 0.001). However, LDL-C values obtained with the precipitation method were 15% higher in hypertriglyceridemics (triglycerides (Tg) > or = 2.3 mmol/l). A paired-comparison between data obtained by both methods indicates a clear serum Tg-values influence, because LDL-C values obtained by the precipitation method were significantly more frequently higher (p < 0.05 or p < 0.01) than LDL-C values obtained using the Friedewald's formula in hypertriglyceridemic men (Tg > or = 1.7 mmol/l or Tg > or = 2.3 mmol/l respectively). When a 3.9 mmol/l LDL-C level break was chosen, Friedewald's formula gave 13% false hypercholesterolemics. The influence of Tg was again significant in men with both, hypercholesterolemia and hypertriglyceridemia, while LDL-C values obtained by the precipitation method were significantly more frequently higher (p < 0.01).