The midsagittal area of the corpus callosum and total neocortical volume differ in three inbred strains of mice

Differences in the midsagittal area of the corpus callosum have been reported between human males and females, between handled and nonhandled rats, and both within and between various strains of mice. This measure has, in addition, been related to handedness in humans and "pawedness" in certain strains of mice. The present study investigated the between- and within-strain differences in three inbred strains of mice, two with autoimmune disorders and spontaneously occurring developmental neuropathology, in the midsagittal area of the corpus callosum, the total neocortical volume, and the asymmetry of the neocortex. These morphometric measures were obtained from coronally sectioned celloidin-embedded material from New Zealand Black (NZB/BINJ), BXSB/MpJ, and DBA/2J mouse strains. NZB mice had a total neocortical volume larger than that of either the BXSB or DBA strains, whereas the BSXB mice had a midsagittal area of the corpus callosum larger than that of either of the other two strains. In addition, there was a positive correlation between these two measures. There was no correlation between total neocortical asymmetry and midsagittal area of the corpus callosum in any of the three strains. Finally, there were no differences in any morphometric measure between animals with or without developmental neuropathology in any given strain.     

Biotransformation of lovastatin--III. Effect of cimetidine and famotidine on in vitro metabolism of lovastatin by rat and human liver microsomes

The effects of the H2-receptor antagonists, cimetidine and famotidine, on the microsomal metabolism of [14C]lovastatin were investigated. Liver microsomes were prepared from control, phenobarbital- and 3-methylcholanthrene-pretreated rats and humans (male and female). Concentration-dependent inhibition of the metabolism of lovastatin (0.1 mM) was observed with cimetidine (0.1 to 1.0 mM). In contrast, famotidine at a similar concentration was a very weak inhibitor. The formation of 6'beta-hydroxy-lovastatin, the major microsomal metabolite of lovastatin, was similarly inhibited. The results suggest that in vivo metabolic interaction with concomitantly administered lovastatin is less likely with famotidine than with cimetidine. Phenobarbital pretreatment produced 58% stimulation in overall metabolism, whereas 3-methylcholanthrene pretreatment had no effect relative to control rats (5.4 nmol/mg protein/min). Liver microsomes from phenobarbital-pretreated rats produced 67% more of the 6'beta-hydroxy-lovastatin but 63-66% less of the 3'-hydroxy and 6'-exomethylene metabolites. Liver microsomes from 3-methylcholanthrene-treated rats also produced less 3"-hydroxy-lovastatin (49%) but similar quantities of the other two metabolites. 6'beta-Hydroxy-lovastatin was a major metabolite with human liver microsomes. Interestingly with these microsomes, hydroxylation at the 3'-position of the molecule was a negligible pathway and hydrolysis to the hydroxy acid form was not observed. The formation of 6'-exomethylene-lovastatin was also catalyzed by human liver microsomes (0.5 to 0.8 nmol/mg protein/min).     

Inhomogeneous exercise uptake and accelerated washout of a radioiodinated fatty acid analogue in syndromeX A SPECT study of the left ventricle

Myocardial metabolism in exercise was determined by studying 21 syndromeX patients and 14 healthy volunteers with an aromatic fatty acid analogue IPPA and a gamma camera. We developed criteria for visual semiquantitative assessment of relative segmental radiotracer uptake and washout, and tested a new computer program for quantitative evaluation. One volunteer (7%) and 12 patients (57%) showed visually inhomogeneous uptake (p=0.006, ²-test) in SPECT polar tomograms after a maximal ergometry test. Images in none of the volunteers and seven patients (33%) gave the impression of a slowed regional washout (p=0.057). Only six patients (29%) had a normal radial polarogram. Patients with irregular coronary angiograms (showing slow flow or minor sclerosis) and those with chest pain during the IPPA exercise test had a very low frequency of normalcy, but this was not significant.Total washout was higher in patients than in the reference population, as the exercise to rest activity ratio was 1.36 SD 0.13 versus 1.25 SD 0.11 in computerized quantitation (p=0.015, t-test). Washout did not correlate with age, sex or exercise heart rate. Regarding computerized analysis of uptake and slow washout, the number of deviant segments was not significantly higher in patients than in reference population. Semiquantitative and quantitative analysis correlated in the assessment of uptake, but not in the assessment of washout. Possible reasons for the discrepancy are discussed.Conclusions of this study are not straightforward. SyndromeX was associated with inhomogeneous IPPA uptake, which is not at variance with the theory of microvascular dysfunction. On the other hand, the analysis of washout presumably implies higher fatty acid utilization in patients than in normal controls, which is not a characteristic phenomenon in myocardial ischemia.     

Biomarkers of styrene exposure in lamination workers: levels of 06-guanine DNA adducts, DNA strand breaks and mutant frequencies in the hypoxanthine guanine phosphoribosyltransferase gene in T-lymphocytes

Occupational exposure to styrene was studied in nine workersof a hand lamination plant in Bohemia. Personal dosimeters wereused to monitor the styrene workplace exposure, and the levelsof styrene in blood and mandelic acid in urine were measured.Blood samples were taken at four occasions during a 7 monthperiod to determine styrene-specific 0⁶-guanine DNA adductsin lymphocytes and granulocytes, DNA strand breaks and hypoxanthineguanine phosphoribosyltransferase (HPRT) mutant frequency inT-lymphocytes. Seven administrative employees in the same factory(factory controls) and eight persons in a research laboratory(laboratory controls) were used as referents. DNA adduct levelsdetermined by the ³²P-postlabelling method in lymphocytes oflamina-tors were remarkably constant and significantly higher(P < 0.0001) than in factory controls at all four samplingtimes. HPRT mutant frequencies (MF) measured by the T-cell cloningassay were higher in the laminators (17.5 x10^–6, groupmean) than in the factory controls (15.7x10^–6, group mean)at three of the four sampling times, but the differences werenot statistically significant. However, a statistically significant(P = 0.021) difference between MF in the laminators (18.0 x10^–6,group mean) and laboratory controls (11.8 xl0^–6, groupmean) was observed at sampling time 4 (the only sampling timewhen this latter group was studied). This result indicates thatstyrene exposure may induce gene mutation in T-cells in vivo.DNA strand breaks were studied by the ‘Comet assay’at the fourth sampling time. The laminators were found to havesignificantly higher levels of DNA strand breaks than the factorycontrols (P = 0.032 for tail length, TL; P = 0.007 for percentageof DNA in tail, T%; and P = 0.020 for tail moment, TM). A statisticallysignificant correlation was also found between the levels oflymphocyte DNA adducts and all three DNA strand break parameters(TL P = 0.046; T% P = 0.026 and TM P = 0.034). On the contrary,no significant correlations were found between DNA adduct levelsand the HPRT mutant frequencies or between the mutant frequenciesand DNA strand breaks. Taken together, these results add furthersupport to the genotoxic and possibly mutagenic effects of styreneexposure in vivo. However, no simple quantitative relationshipseems to exist between the levels of styrene-induced DNA damageand frequency of HPRT mutation in T-lymphocytes.     

Distribution of bratton-marshall-positive material in mice following intravenous injections of nitrosoureas

Summary As determined by a colorimetric assay measuring parent compounds plus ether-extractable, nitroso-containing metabolites, N,N-bis(2-chloroethyl)-N-nitrosourea (BCNU) disappeared more rapidly than N-(2-chloroethyl)-N cyclohexyl-N-nitrosourea (CCNU) and N-(2-chloroethyl)-N-(4-transmethylcyclohexyl)-N-nitrosourea (MeCCNU) and their products from the tissues of mice injected IV. Assay of selected samples by high-pressure liquid chromatography revealed that the colorimetric assay for BCNU was specific in that the two assays gave equivalent results. Following IV-injections of CCNU and MeCCNU, however, levels of the parent compounds decreased much more rapidly than the total, color-producing material.Of seven tissues, the largest Cxt values for BCNU, as determined by the colorimetric assay, were noted for blood (442 g-min/ml) and large intestine (285 g-min/g). Liver (29 g-min/g) had the lowest Cxt value, reflecting rapid metabolism of the compound by this organ. Color-producing material related to CCNU disappeared from the solid tissues of mice in a manner generally parallel to that for blood. Of the Cxt values for this compound and its products, those for lung (1753 g-equivalents-min/g), kidney (1633 g-equivalents-min/g), and small intestine (1557 g-equivalents-min/g) were highest. Consistent with its slower rate of metabolism, MeCCNU and its color-producing metabolites remained in most tissues of mice for 12 h following injection. Except for brain (1434 g-equivalents-min/g), Cxt values for this nitrosourea and its metabolites in tissues were higher than those of blood (5485 g-equivalents-min/ml), with kidney (15,324 g-equivalents-min/g), liver (12,921 g-equivalents-min/g), and large intestine (11,501 g-equivalents-min/g) being highest. For each nitrosourea, a fair correlation was observed between the Cxt values for tissues and the toxic and/or antitumor effects at those sites.     

Effect of Different Respirator Adjustments on Central Haemodynamics in Open-Heart Surgery Patients

Changes in cardiac index (CI) mean pulmonary artery pressure (PAP), mean pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), and pulmonary artery vascular resistance (PVR), associated with spontaneous respiration (SR) and two different types of intermittent positive pressure ventilation (IPPPV and IPNPV) were studied in a total of 17 patients undergoing aortic valve replacement or myocardial revascularization. Swan-Ganz thermodilution pulmonary artery cardiac output catheters were used and the aim was to determine: whether postoperative cardiac output may paradoxically be greater during IPPPV than during IPNPV or SR; whether the use of "negative" pressure in the expiratory phase during controlled ventilation may be responsible for bringing about the central haemodynamic conditions prevailing during spontaneous respiration; and whether, in weaning from postoperative IPPPV to SR, there is a risk of pulmonary congestion as a consequence of possible autotransfusion. IPPPV connected with anaesthesia induction caused a highly significant deterioration central haemodynamics. The use of positive end-expiratory pressure (PEEP) is not to be recommended for such patients at this stage. On the first postoperative day, the mean CI was lower during IPPPV than during IPNPV (P less than 0.1) or during SR (P less than 0.05). The changes observed in CI, were, however, so slight that the authors consider the routine use of PEEP to be beneficial during controlled ventilation following major open-heart surgery. In some patients, the CI was paradoxically higher during IPPPV than during IPNPV or SR. The mean CI was nearly the same during IPNPV (3.32) as during SR (3.38). However, PAP, PCWP and PVR values were significantly higher during SR than during IPNPV. Thus, according to this study, the use of "negative" end-expiratory pressure during controlled ventilation did not in these patients produce central pressure conditions corresponding to spontaneous respiration. The present study supports the finding that in weaning from controlled ventilation with PEEP to SR there is a danger of pulmonary congestion. This could be predicted by measurement of pulmonary wedge pressure, but not by measurement of central venous pressure.     

Familial lung cancer and aggregation of smoking habits: a simulation of the effect of shared environmental factors on the familial risk of cancer.

BACKGROUND: Tobacco smoking is the principal cause of lung cancer. The risk of lung cancer in the offspring of lung cancer patients is about twice higher than the risk in the general population. The present study investigated the contribution of shared smoking habits to the familial clustering of lung cancer. METHODS: We estimated the relative risk of lung cancer attributable to smoking according to the extent to which smokers transmit their smoking habits to the offspring (heritability of smoking), the prevalence of smoking in the general population, and the risk of lung cancer for smokers compared with nonsmokers. FINDINGS: The relative risk of lung cancer for the offspring of lung cancer patients attributable to smoking was 1.19 when published data on smoking practice were modeled (i.e., assuming that the heritability of smoking was 0.5, the smoking prevalence 40%, and the odds ratio of lung cancer for smokers versus nonsmokers was 20). INTERPRETATION: Most familial cases of lung cancer cannot be attributed to shared smoking habits. The example of smoking can be used for other familial cancers, for which no strong environmental risk factors are usually known, to infer the primary role for heritable genes.     

Familial aggregation and heterogeneity of non-Hodgkin lymphoma in population-based samples.

The importance of genetic factors in the etiology of non-Hodgkin lymphoma (NHL) is suggested by case-control and cohort studies. Most previous studies have been too small to estimate accurately risks of specific categories of lymphoproliferative malignancies in relatives of NHL cases or to quantify the contribution of NHL case characteristics to familial risk. We have overcome sample size limitations and potential recall bias by using large databases from Sweden and Denmark. Diagnoses of lymphoproliferative malignancies were compared in 70,006 first-degree relatives of 26,089 NHL cases (including 7,432 with subtype information) versus 161,352 first-degree relatives of 58,960 matched controls. Relatives of NHL cases were at significantly increased risk for NHL [relative risk (RR), 1.73; 95% confidence interval (95% CI), 1.39-2.15], Hodgkin lymphoma (RR, 1.41; 95% CI, 1.0-1.97), and nonsignificantly for chronic lymphocytic leukemia (CLL; RR, 1.31; 95% CI, 0.93-1.85). No increased risk was found for multiple myeloma among case relatives. Findings with respect to siblings compared with parents and offspring or with respect to age at diagnosis of proband were inconsistent. In both populations, relatives of cases with an aggressive NHL subtype were at substantially increased risk of NHL (combined RR, 3.56; 95% CI, 1.80-7.02). We conclude that NHL has an important familial component, which is shared with Hodgkin lymphoma and CLL. We estimate that the absolute lifetime risk for a first-degree relative of an NHL case to develop NHL is 3.6% (compared with a population risk of 2.1%) and higher if the index case had an aggressive subtype of NHL.     

QTQTN motif upstream of the furin-cleavage site plays a key role in SARS-CoV-2 infection and pathogenesis

The furin cleavage site (FCS), an unusual feature in the SARS-CoV-2 spike protein, has been spotlighted as a factor key to facilitating infection and pathogenesis by increasing spike processing. Similarly, the QTQTN motif directly upstream of the FCS is also an unusual feature for group 2B coronaviruses (CoVs). The QTQTN deletion has consistently been observed in in vitro cultured virus stocks and some clinical isolates. To determine whether the QTQTN motif is critical to SARS-CoV-2 replication and pathogenesis, we generated a mutant deleting the QTQTN motif (ΔQTQTN). Here, we report that the QTQTN deletion attenuates viral replication in respiratory cells in vitro and attenuates disease in vivo. The deletion results in a shortened, more rigid peptide loop that contains the FCS and is less accessible to host proteases, such as TMPRSS2. Thus, the deletion reduced the efficiency of spike processing and attenuates SARS-CoV-2 infection. Importantly, the QTQTN motif also contains residues that are glycosylated, and disruption of its glycosylation also attenuates virus replication in a TMPRSS2-dependent manner. Together, our results reveal that three aspects of the S1/S2 cleavage site—the FCS, loop length, and glycosylation—are required for efficient SARS-CoV-2 replication and pathogenesis.

SARS-CoV-2 emerged in late 2019 and has caused the largest pandemic since the 1918 influenza outbreak (1). An unusual feature of SARS-CoV-2 is the presence of a furin cleavage site (FCS) in its spike protein (2). The CoV spike is a trimer of spike proteins composed of the S1 and S2 subunits, responsible for receptor binding and membrane fusion, respectively (1). After receptor binding, the spike protein is proteolytically cleaved at the S1/S2 and S2′ sites to activate the fusion machinery. For SARS-CoV-2, the spike protein contains a novel cleavage motif recognized by the host cell furin protease (PRRAR) directly upstream of the S1/S2 cleavage site that facilitates cleavage prior to virion release from the producer cell. This FCS, not found in other group 2B CoVs, plays a key role in spike processing, infectivity, and pathogenesis as shown by our group and others (3, 4).Importantly, another novel amino acid motif, QTQTN, is found directly upstream of the FCS. This QTQTN motif, also absent in other group 2B CoVs, is often deleted and has been pervasive in cultured virus stocks of the alpha, beta, and delta variants (5–8). In addition, the QTQTN deletion has been observed in a small subset of patient samples as well (9–11). Because this deletion has been frequently identified, we set out to characterize it and determine whether it has consequences for viral replication and virulence. Using our infectious clone (12, 13), we demonstrated that the loss of this motif attenuates SARS-CoV-2 replication in respiratory cells in vitro and pathogenesis in hamsters. The QTQTN deletion results in reduced spike cleavage and diminished capacity to use serine proteases on the cell surface for entry. Importantly, mutations of glycosylation-enabling residues in the QTQTN motif results in similar replication attenuation despite intact spike processing. Together, our results highlight elements in the SARS-CoV-2 spike in addition to the FCS that contribute to increased replication and pathogenesis.     

Isolation,characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali

ContextGlobal studies on Argemone mexicana L. (Papaveraceae) traditionally used against malaria in Mali are limited to its low-mass compounds activities, and little information on its bioactive polysaccharides is available.ObjectiveThis study determines the structure and the immunomodulatory activity of polysaccharides from aerial parts of A. mexicana.Materials and methodsAcidic polysaccharides from this plant material named HMAmA1 and HMAmA2 were isolated from water extracts. Their monosaccharide composition was determined by gas chromatography. Glycosidic linkages were determined using GC-MS. NMR was also applied. The polymers were tested for effects on the human complement system in vitro at different doses.ResultsThe monosaccharide composition showed that the two polysaccharides contained in different amounts the following monomers: arabinose, rhamnose, galactose, and galacturonic acid. Overall structural analysis showed the presence of a low ratio of 1,2-linked rhamnose compared to 1,4-linked galacturonic acid with arabinogalactans substituted on position 4 of rhamnose. NMR data showed the presence of galacturonans alternated by rhamnogalacturonans bearing arabinose and galactose units. α-Linkages were found for l-arabinose, l-rhamnose and d-galacturonic acid, while β-linkages were found for d-galactose. The two polysaccharides exhibited strong complement fixation activities, with HMAmA1 being the highest potent fraction. ICH₅₀ value of HMAmA1 was 5 µg/mL, compared to the control BPII being 15.9 µg/mL.Discussion and conclusionsPolysaccharides form A. mexicana presented a complement fixation effect. The complement system is an important part of the immune defense, and compounds acting on the cascade are of interest. Therefore, these polymers may be useful as immunodulatory agents.