Association between dietary calcium intake and severe abdominal aorta calcification among American adults: a cross-sectional analysis of the National Health and Nutrition Examination Survey

BACKGROUND

Evidence regarding the relationship between dietary calcium intake and severe abdominal aortic calcification (AAC) is limited. Therefore, this study aimed to investigate the association between dietary calcium intake and severe AAC in American adults based on data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

The present cross-sectional study utilized data from the NHANES 2013-2014, a population-based dataset. Dietary calcium intake was assessed using two 24-h dietary recall interviews. Quantification of the AAC scores was accomplished utilizing the Kauppila score system, whereby severe AAC was defined as having an AAC score greater than 6. We used multivariable logistic regression models, a restricted cubic spline analysis, and a two-piecewise linear regression model to show the effect of calcium intake on severe AAC.

RESULTS

Out of the 2640 individuals examined, 10.9% had severe AAC. Following the adjustment for confounding variables, an independent association was discovered between an augmented intake of dietary calcium and the incidence of severe AAC. When comparing individuals in the second quartile (Q2) of dietary calcium intake with those in the lowest quartile (Q1), a decrease in the occurrence of severe AAC was observed (odds ratio: 0.66; 95% confidence interval: 0.44-0.99). Furthermore, the relationship between dietary calcium intake and severe AAC demonstrated an L-shaped pattern, with an inflection point observed at 907.259 mg/day. Subgroup analyses revealed no significant interaction effects.

CONCLUSION

The study revealed that the relationship between dietary calcium intake and severe AAC in American adults is L-shaped, with an inflection point of 907.259 mg/day. Further research is required to confirm this association.

[Infection with L-form of Helicobacter pylori and expressions of MIF, MMP9 and VEGF in gastric carcinoma]

OBJECTIVE

To investigate the correlation between infection with L-form of Helicobacter pylori (Hp-L) and the expressions of macrophage migration inhibition factor (MIF), matrix metalloproteinase 9 (MMP9), and vascular endothelial growth factor (VEGF) in gastric cancer.

METHODS

Hp-L was examined in 80 gastric carcinoma and 50 adjacent normal tissues by Gram staining and immunohistochemical staining, and the expressions of MIF, MMP9 and VEGF were detected by immunohistochemical staining; the expression of MIF mRNA was detected by RT-PCR and the expression of MIF, MMP9 and VEGF proteins were detected by Western blotting in 30 fresh gastric cancer tissues and the corresponding adjacent tissues.

RESULTS

Of the 80 gastric carcinoma tissues, 57 (71.25%) showed Hp-L positivity detected by both Gram staining and immunohistochemical staining, as compared with a rate of only 14% in the adjacent normal tissues (P<0.05). The gastric carcinoma tissues showed higher expression levels of MIF, MMP9 and VEGF proteins than the corresponding adjacent normal mucosa; the positivity MIF, MMP-9 and VEGF proteins were significantly higher in Hp-L-positive gastric carcinoma than in Hp-L-negative cases (P<0.05). Positive correlations were found between Hp-L positivity and the expressions of MIF, MMP-9 and VEGF (r=0.598, 0.292, 0.341, respectively, P<0.05). The 30 fresh gastric cancer tissues showed also significantly higher MIF mRNA expression and MIF, MMP-9 and VEGF protein expressions than the adjacent tissues (t=3.729, P<0.01). The expressions of MIF and MMP-9 were also related to the clinicopathological factors including lymph node metastasis and depth of invasion (P<0.05).

CONCLUSION

Infection with L-form of Hp-L can be an important factor that contributes to the invasion and metastasis of gastric carcinoma, the mechanism of which involves up-regulated expressions of MIF, MMP-9 and VEGF.

Role of α-toxin-induced apoptosis of umbilical vein endothelial cells in vertical infection of Staphylococcus aureus L-form

OBJECTIVE

To investigate α-toxin-induced apoptosis of umbilical vein endothelial cells and explore its role in vertical infection of Staphylococcus aureus L-form.

METHODS

HUV-EC-C cells exposed to different concentrations (0, 10, 30, 90, and 270 ng/ml) of α-toxin for different time lengths (0, 2, 4, 6, and 8 h) were examined for apoptosis using flow cytometry with Annexin V-PI staining. The levels of tumor necrosis factor-α (TNF-α) and the activities of, caspase-3 and caspase-8 in the cell culture were detected by ELISA and colorimetric method, respectively. α-Toxin-induced cell apoptosis was also analyzed in HUV-EC-C cells treated with a neutralizing antibody of TNF-α or with the inhibitory peptides of caspase-3 (zDEVD-FMK) and caspase-8 (zIETD-fmk).

RESULTS

α-Toxin induced apoptosis of HUV-EC-C cells in a dose- and time-dependent manner and caused significantly enhanced expression of TNF-α and the activation of both caspase-3 and caspase-8. Inhibition of TNF-α with its neutralizing antibody and the inhibitory peptides of caspase-3 or -8 all significantly decreased α-toxin-induced cell apoptosis, and the caspase-3 inhibitor completely blocked α-toxin-induced cell apoptosis.

CONCLUSION

α-Toxin-induced apoptosis is partially mediated by the extrinsic cell death pathway of TNF-α and caspase-8 and plays an important role in the vertical infection of S. aureus L-form to affect fetal growth and development.

Polar lipid and fatty acid profiles – Re-vitalizing old approaches as a modern tool for the classification of mycoplasmas?

A set of 20 Mollicutes strains representing different lines of descent, including the type species of the genus Mycoplasma, Mycoplasma mycoides, Acholeplasma laidlawii and a strain of Mesoplasma, were subjected to polar lipid and fatty acid analyses in order to evaluate their suitability for classification purposes within members of this group. Complex polar lipid and fatty acid profiles were detected for each examined strain. All strains contained the polar lipids phosphocholine-6'-alpha-glucopyranosyl-(1'-3)-1, 2-diacyl-glycerol (MfGL-I), 1-O-alkyl/alkenyl-2-O-acyl-glycero-3-phosphocholine (MfEL), sphingomyelin (SphM), 1-O-alkyl/alkenyl-glycero-3-phosphocholine (lysoMfEL), the unknown aminophospholipid APL1 and the cholesterol Chol2. A total of 19 strains revealed the presence of phosphatidylethanolamine (PE) and/or phosphatidylglycerol (PG), and the presence of diphosphatidylglycerol (DPG) was detected in 13 strains. The unknown aminolipid AL1 was found in the extracts of 17 strains. Unbranched saturated and unsaturated compounds predominated in the fatty acid profiles. Major fatty acids were usually C16:0, C18:0, C18:1 omega9c and 'Summed feature 5' (C18:2 omega6, 9c/C18:0 anteiso). Our results demonstrated that members of the M. mycoides cluster showed rather homogenous polar lipid and fatty acid profiles. In contrast, each of the other strains was characterized by a unique polar lipid profile and significant quantitative differences in the presence of certain fatty acids. These results indicate that analyses of both polar lipid and fatty acid profiles could be a useful tool for classification of mycoplasmas.

[Clinical picture of genital tuberculosis in different forms of its pathogen]

Improvement of bacteriological diagnosis is of great value for the clinical picture of genital tuberculosis. The purpose of the study is to reveal the clinical features of genital tuberculosis in L-forms of Mycobacterium tuberculosis (MBT) versus traditional bacteriological methods and polymerase chain reaction (PCR) test with MBT DNA. A hundred and fourteen patients with verified active genital tuberculosis were examined. They were divided into 3 groups: 1) 36 patients with L-forms of MBT in the endometrial scrapes; 2) 32 with bacteriologically verified GT; 3) 46 with positive PCR test. A control group (Group 4) comprised 120 patients with NGD. Among the patients with L-forms there were prevalent females aged 21-40 years (83.4%). These patients had a history of spontaneous abortions more frequently than patients from other groups, in a third was found to have MBT with their L-variants. Signs of intoxication were observed in 47.2%. Oviductal obliteration and specific changes typical of tuberculosis were revealed on a hysterogram in 63.9%, other forms of prior and current extragenital tuberculosis were detected in a half of cases, traces of prior pulmonary tuberculosis were observed in 15%, 63.9% of the patients with L-forms and in 87% of those with positive PCR test were found to have pathological changes in the endometrium, which is indirectly indicative of its lesion. Thus, detection of L-forms of MBT in the endometrial scrapes leads to the conclusion that this is an active sluggish hematogenic tuberculous process, which is evidenced by a complex clinical and laboratory study.

[Using L-form bacterium ATP bioluminescence assay for rapid testing L-form bacterial susceptibility]

Adenosine triphosphate is a kind of necessary metabolites in living cells. The authors detected ATP contents by using bioluminescence method in 111 strains of L-form bacteria after exposing to 5 kinds of antibiotics. The results showed that the mean value of CPM was less than (35 +/- 10.2)%.s-1. Thus, the value could be acted as a critical concentration between susceptibility and resistance. The conincidence rate of this method and K-B method was 95.3%. It indicates that the bioluminescence method has a high sensitivity. It can be used to detect L-form bacterium-drug susceptibility quickly and may play an important role for choosing the antibiotics.

Cell-wall-deficient forms of Staphylococcus aureus as lung pathogens: an ultrastructural study

The interaction between stable protoplast L forms of Staphylococcus aureus and the alveolar wall of infected rats was observed in the course of experimental pulmonary infection (days 3, 7, 14, and 30 p.i.). The L forms were successfully cultivated from bronchoalveolar lavage samples taken throughout the tested interval. The ultrastructural results demonstrated the ability of the L forms to invade the alveolar wall where they established, grew and reproduced mainly in the interstitium. The infection caused lung lesions: granulomas, focal fibroses and destruction of type I alveolar epithelial cells.

[Retrospective study on the risk factors in patients with nosocomial bacterial L-form infection]

To survey the risk factors of nosocomial bacterial L-form infections, 22 risk factors were investigated and analysed with nonconditional logistic regression. Resutts showed through single factor regression that cancer, chronic disease, primary infection, longer than 3-week hospitalization before the onset of nosocomial infection, preventive use of antibiotics longer than 7 days, preventive use of cell wall depressive antibiotics, steroid use, anti-tumor drugs and urine guide technique were significant factors. Multiple factor regression demonstrated that two models including cell wall depressive antibiotics, primary infection, urine guide technique cell wall depressive antibiotics, primary infection, anti-tumor drugs and longer than 3-week hospitalization before the development of nosocomial infection were conjugated properly. It suggested that the surveillance of risk factors of nosocomial bacterial L-form infections was helpful to control nosocomial infections.

Occurrence of catalase in pleuropneumonia-like organisms and bacterial L forms

Weibull, C. (Central Bacteriological Laboratory of Stockholm City, Stockholm, Sweden) and Kerstin Hammarberg. Occurrence of catalase in pleuropneumonia-like organisms and bacterial L forms. J. Bacteriol. 84:520-525. 1962.-The catalase activity of six pleuropneumonia-like organisms (PPLO), four stable Proteus L forms, and four normal strains of Proteus mirabilis was determined quantitatively. The PPLO (strains of the species Mycoplasma agalactiae, hominis, laidlawii, mycoides, and strains isolated from tissue cultures) exhibited no measurable catalase activity. The L forms decomposed H(2)O(2) approximately ten times as rapidly as the normal bacteria from which they were derived.

Studies of L forms and protoplasts of group A streptococci. I. Isolation, growth, and bacteriologic characteristics

L forms of Group A streptococci have been isolated by the use of penicillin gradient agar plates. Osmotically fragile protoplasts of Group A streptococci have been obtained by the use of Group C phage-associated lysin which lyses Group A streptococci and their isolated cell walls. Membranes surrounding these enzymatically derived protoplasts have been isolated, and chemical and immunological studies indicate that they are free of cell wall carbohydrate and M protein. The streptococcal protoplasts reproduce as colonies which are morphologically indistinguishable from streptococcal L forms. Evidence is presented to show that these two streptococcal derivatives are serologically and physiologically related to each other as well as to the parent streptococcal strain from which they were isolated.

Morphology of pleuropneumonia-like organisms and bacterial L forms grown in liquid media

Weibull, C. (Central Bacteriological Laboratory of Stockholm City, Stockholm, Sweden) and Britt-Marie Lundin. Morphology of pleuropneumonia-like organisms and bacterial L forms grown in liquid media. J. Bacteriol. 85:440-445. 1963.-Cells of Mycoplasma hominis, M. laidlawii, and two tissue-culture strains of pleuropneumonia-like organisms (PPLO) moving freely in liquid medium were photographed with an electronic flash as the light source. The photomicrographs thus obtained demonstrated that, in young cultures of high viability, the cells of these organisms were mainly filamentous or, in the case of M. laidlawii, coccoid. In old cultures of the same organisms containing predominantly nonviable cells, granular and vesicular elements were found. By the use of the same photographic technique, liquid cultures of a stable Proteus L form were studied. Although no filaments of uniform thickness were found, there were spherical bodies and some threadlike material connected with the spheres. When samples of PPLO cultures containing filamentous forms were transferred to agar blocks, the filaments were converted to more or less spherical bodies. This conversion could be prevented by fixing the PPLO with formaldehyde. The morphology of Proteus L forms was not noticeably altered by fixation with this reagent.

Studies on L forms and protoplasts of group A streptococci. II. Chemical and immunological properties of the cell membrane

Intact bacterial membranes have been isolated from protoplasts prepared from Group A streptococci by a cell wall-dissolving enzyme. A membrane fraction with identical chemical and serological properties has been obtained by differential centrifugation of mechanically disrupted streptococci. The membrane is chemically distinct from the cell wall and is composed of 72 per cent protein, 26 per cent lipid, and 2 per cent carbohydrate. Capillary precipitin tests and analysis by microdiffusion have demonstrated that the membrane contains antigens distinct from those of the cell wall and from those of the cytoplasm which it envelops. Evidence is presented which demonstrates that this antigenic material is common to the membranes of Group A streptococci, and that it can be distinguished by immunodiffusion from related antigenic substances present in membranes of several other serological groups of hemolytic streptococci. This antigenic material does not cross-react with the membrane antigens of other Gram-positive cocci.

Induction and characteristics of staphylococcal L forms

Staphylococcal L forms revealed characteristics not observed previously. The ability to produce coagulase was retained by the variant. In the presence of blood, many L forms were found within red cells, comparable with the intraerythrocytic stages reported for streptococci. Agar lysis was a unique characteristic of the mature L form.Inhibitors were not required to initiate the L stage and the variant and classical form grew commensally on enriched media. As nutrition was simplified, the L stage was supported, whereas the classical form did not reproduce. A small inoculum resulted in exclusive growth of L forms even in media containing special growth factors. The relative ease with which the L forms are produced experimentally suggests that this phase of growth may occur in vivo.

Clinical and bacteriologic study of eighty-six patients with systemic lupus erythematosus complicated by infections

OBJECTIVE

To investigate the clinical and bacteriologic features of patients with systemic lupus erythematosus (SLE) complicated by bacterial and/or fungal infections.

METHODS

Statistical analysis was made on basis of the clinical and bacteriologic data of 86 patients with SLE complicated by bacterial and/or fungal infections.

RESULTS

One hundred and thirty-three episodes of infections occurred in 86 patients with SLE, in which 51.13% were nosocomial infections and 76.69% occurred in the blood system, respiratory tract, lungs and urinary tract. Gram-negative bacilli, gram-positive cocci, fungal and other bacterial infections accounted for 39.85%, 31.58%, 18.80% and 9.77%, respectively. In the bacterial infections, 18.52% were caused by L-form bacteria and more than 60% of the patients had no apparent toxic manifestations. The odds ratio (OR) of infection increased significantly in patients with damaged functions of the heart, lungs and kidneys, and in those who received high-dosage steroids.

CONCLUSIONS

Patients with SLE tend to develop nosocomial infections with gram-negative bacilli which are the most common pathogens. The clinical manifestations of the infection are atypical. Careful inspection and monitoring, timely collecting the specimens for L-form bacterial culture can reduce misdiagnosis and missed diagnosis of the infection.

METABOLIC PROPERTIES OF SOME L FORMS DERIVED FROM GRAM-POSITIVE AND GRAM-NEGATIVE BACTERIA

Weibull Claes (Central Bacteriological Laboratory of Stockholm City, Stockholm, Sweden), and Hans Gyllang. Metabolic properties of some L forms derived from gram-positive and gram-negative bacteria. J. Bacteriol. 89:1443-1447. 1965.-L forms of two gram-positive bacteria, a staphylococcus and a diphtheroid, were found to be devoid of catalase and cytochromes, whereas the normal bacteria from which these L forms were derived contained large amounts of these enzymes. On the other hand, L forms of a gram-negative bacterium, Proteus mirabilis, contained the same cytochromes as normal Proteus bacteria. (Previous investigations showed that normal cells and L forms of P. mirabilis contain approximately the same amounts of catalase.) The respiratory quotients (Q(O2)) of all L forms studied were much lower than those of the corresponding normal bacteria. The conversion of the normal organisms into L forms did not markedly affect their growth rate, measured as the time required for doubling the bacterial mass during the exponential-growth phase.

SENSITIVITY OF COCCAL AND L FORMS OF STAPHYLOCOCCUS AUREUS TO FIVE ANTIBIOTICS

Kagan, B. M. (Cedars of Lebanon Hospital, Los Angeles, Calif.), Susan Zolla, R. Busser, and Silvija Liepnieks. Sensitivity of coccal and L forms of Staphylococcus aureus to five antibiotics. J. Bacteriol. 88:630-632. 1964.-Antibiotics whose primary site of action is in the cell wall (penicillin and cephalothin) do not inhibit growth of L-phase organisms. In this study, kanamycin, neomycin, polymyxin B, lincomycin, and gentamycin were found to be more active against L-phase growth of Staphylococcus aureus in vitro than against the coccal forms. Therefore, their primary site of antimicrobial activity appears to be other than that involved in the synthesis or integrity of the cell wall.

ISOLATION OF L FORMS FROM GROUP A STREPTOCOCCI EXPOSED TO BACITRACIN

Rotta, Jiri (Washington University School of Medicine, St. Louis, Mo.), Walter W. Karakawa, and Richard M. Krause. Isolation of L forms from group A streptococci exposed to bacitracin. J. Bacteriol. 89:1581-1585. 1965.-L forms were obtained from group A streptococci by exposure to bacitracin on gradient plates, although novobiocin was ineffective in this respect. Subcultures of these L forms had morphological and bacteriological properties similar to those obtained with penicillin. M protein was detected in L-form colony smears by immunofluorescent staining with type-specific conjugate. The L forms were not stained with group-specific conjugate. Parallel precipitin tests performed with extracts from a heavy growth of L forms on agar confirmed these findings. Thus, the L forms obtained with bacitracin continue to produce M protein but are devoid of the group-specific carbohydrate which is a major component of cell-wall structure.