The vasa vasorum and angioplasty

Interruption of flow in the vasa vasorum may lead to medial necrosis and aneurysm formation. The purpose of this study was to determine whether angioplasty produces significant alterations in the morphology or blood flow of the vasa vasorum of the dilated artery. The morphology of the canine vasa vasorum was studied before and after angioplasty; in a separate experiment vessel wall blood flow (VWBF) in canine carotid arteries was measured after angioplasty to determine whether physiologic regulation of the blood flow was disrupted by arterial dilation. No morphologic changes could be demonstrated in the vasa vasorum of the dilated artery; however, VWBF was increased by 1194 +/- 215% (mean +/- standard error, p less than 0.01) between 90 and 120 minutes after angioplasty. VWBF in the adjacent nondilated arterial segment was also increased (720 +/- 177% between 10-30 minutes, p less than 0.01) but returned toward normal after 60 minutes. Adenosine caused a "paradoxical" decrease in VWBF (p less than 0.05) of the dilated arterial segment while causing increased VWBF (p less than 0.05) in the thoracic aorta. Angioplasty appears to produce persistent hyperemia in the dilated arterial wall. A paradoxical response to adenosine suggests that vasa vasorum in the dilated arterial segment are maximally vasodilated. This may be due to mechanical disruption of vasomotor tone or to release of vasoactive substances.     

Antibodies in sera from patients with inflammatory demyelinating polyradiculoneuropathy react with ganglioside LM1 and sulphatide of peripheral nerve myelin

Summary Sera from 23 patients with acute Guillain Barré syndrome (GBS), 15 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and from 40 age-matched blood donors were analysed for antibodies to acidic glycosphingolipids from human brain and peripheral nerve. Antibodies to ganglioside LM1, the major ganglioside of peripheral nerve myelin, were found in 43% of GBS and in 67% of CIDP patients' sera, and in 20% of the blood donors. However, anti-sulphatide antibodies were detected in 65% and 87% of the sera from GBS and CIDP patients, respectively, but only in 15% of the control sera. Sulphatide is the major acidic glycosphingolipid in myelin and its concentration in peripheral nerve myelin is 100 times higher than that of LM1. The high frequency of LM1 and, in particular of sulphatide antibodies, might thus be relevant to the pathogenesis of the GBS and CIDP. Abbreviations: The ganglioside nomenclature used according to Svennerholm [24]. LM1, IV³NeuAc-nLcOse₄Cer, GM1, II³NeuAcGgOse₄Cer; GD1a, IV³NeAc,II³NeuAc-GgOse₄Cer; GD1b, II³(NeuAc)₂-GgOse₄Cer; GT1b, IV³NeuAc,II³(NeuAc)₂-GgOs₄Cer; LU1, sulphate-3-glucuronyl paragloboside; sulphatide, 3-sulphogalacto-sylceramide     

The clinical effect and the effect on serum IgG antibodies to peripheral nerve tissue of plasma exchange in patients with Guillain-Barré syndrome

Summary The mixed haemagglutination technique was used to demonstrate IgG antibodies to peripheral nerve tissue in sera from patients with the Guillain-Barré syndrome. The clinical effect and the effect on the antibodies of plasma exchange were examined in 18 patients. Neurological examination with muscle testing and neurophysiological examination of the patients were performed before and immediately after plasma exchange. Before the exchange antibodies were detected in sera from 11 of the patients. These patients showed clinical improvement during the treatment. After plasma exchange, antibodies were detected in sera from only two of the patients. The seven patients without detectable antibodies showed no clinical improvement.

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Zusammenfassung Bei 18 Patienten mit Guillain-Barré Syndrom, die einem therapeutischen Plasmaaustausch (PA) unterzogen wurden, wurde das Serum mit Hilfe einer gemischten Hämagglutinations-Technik auf IgG-Antikörper (IgG-AK) gegen peripheres Nervengewebe untersucht. Einfluß der PA auf den klinischen Zustand und Titerverlauf wurden verglichen: Bei 11 Patienten wurden IgG-AK gefunden; sie zeigten unter der PA eine klinisch verifizierte Besserung, die in einigen Fällen auch elektromyographisch gesichert werden konnte; nach Beendigung der PA waren nur noch in 2 Fällen IgG-AK nach-weisbar. Bei den restlichen 7 Patienten fehlten IgG-AK; bei ihnen war die PA ohne Effekt.

     

The influence of reported paternal attitudes on the decision to breast-feed

Objective: To identify factors that influence a woman's decision to breast-feed.
Methodology: Five hundred and fifty-six women were recruited from the maternity wards of two Perth hospitals. Data were collected from a self-administered questionnaire completed by participants prior to discharge. Logistic regression analysis was used to determine factors influencing the initiation of breast-feeding.
Results: At discharge from hospital 83.8% of women were breast-feeding, including 6% who were giving complementary formula feeds. After controlling for potentially confounding demographic and biomedical factors, the father's reported preference for breast-feeding was found to be the most important factor influencing a woman's decision to breast-feed (OR 10.18).
Conclusion: Fathers participate in and influence the choice of infant feeding method and should be included in breast-feeding discussions.     

Bacterial and mammalian DNA alkyltransferases sensitize Escherichia coli to the lethal and mutagenic effects of dibromoalkanes

Here we confirm and extend our previous studies demonstrating that the mutagenic potency of 1,2-dibromoethane (DBE) and dibromomethane (DBM) is markedly enhanced (not prevented) in bacteria expressing the O6- alkylguanine-DNA alkyltransferase (ATase) encoded by the Escherichia coli ogt gene. We demonstrate that, in close parallel with mutagenesis, the Ogt ATase sensitizes the bacteria to the lethal effects of these carcinogens, suggesting that one or more of the potentially mutagenic lesions induced by DBE and DBM in the presence of Ogt has additional lethal capacity. We further demonstrate that the sensitization to both lethality and mutagenesis by DBE and DBM is a property shared by other DNA alkyltransferases. This objective was accomplished by quantifying the induction of mutations and lethal events in ogt- ada- E. coli expressing an exogenous bacterial or mammalian ATase from a multicopy plasmid. Mammalian recombinant ATases enhanced the lethal and mutagenic actions of DBE and suppressed the lack of sensitivity of the vector- transformed bacteria to DBM. In most cases the order of effectiveness of the ATases ranked: murine > human > Ogt > rat. Further comparisons included the full-length Ada ATase from E. coli and a truncated Ada version (T-ada) that retains the O6-methylguanine binding domain of the protein. The full-length Ada ATase was effective in enhancing the lethality but not the mutagenicity induced by DBE and DBM. The T-ada ATase provided less sensitization than Ada to lethality by DBE, but of the three bacterial ATases T-ada yielded the highest sensitization to mutagenesis by this compound. T-ada and Ada ATases were in general less effective than the mammalian versions, with the exception of the rat recombinant ATase. The effectiveness of the different mammalian and bacterial ATases in promoting the deleterious actions of dibromoalkanes was compared with the effectiveness of these proteins in suppressing the lethal and mutagenic effects induced by N-nitroso-N-methylurea. The ability to sensitize E. coli to the lethal and mutagenic effects of DBE and DBM seems restricted to DNA alkyltransferase, since overexpression of thioredoxin (Trx) or glutaredoxin (Grx1) in ogt- ada- cells showed no effect, in spite of the reported potential of bioactive dihaloethane- derived species to alkylate Trx.      

Dibenzo[a,l]pyrene-induced DNA adduction, tumorigenicity, and Ki-ras oncogene mutations in strain A/J mouse lung

Dibenzo[a,l]pyrene (DB[a,l]P), an environmental polycyclic aromatic hydrocarbon, is the most potent carcinogen ever tested in mouse skin and rat mammary gland. In this study, DB[a,l]P was examined for DNA adduction, tumorigenicity, and induction of Ki-ras oncogene mutations in tumor DNA in strain A/J mouse lung. Groups of mice received a single i.p. injection of 0.3, 1.5, 3.0, or 6.0 mg/kg DB[a,l]P in tricaprylin. Following treatment, DNA adducts were measured at times between 1 and 28 days, while tumors were counted at 250 days and analyzed for the occurrence of point mutations in codons 12 and 61 of the Ki-ras oncogene. DB[a,l]P in strain A/J mouse lung induced six major and four minor DNA adducts. Maximal levels of adduction occurred between 5 and 10 days after injection followed by a gradual decrease. DB[a,l]P-DNA adducts in lung tissue were derived from both anti- and syn-11,12- dihydroxy-13,14-epoxy- 11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE) and both deoxyadenosine (dAdo) and deoxyguanosine (dGuo) residues in DNA as revealed by cochromatography. The major adduct was identified as a product of the reaction of an anti-DB[a,l]PDE with dAdo in DNA. DB[a,l]P induced significant numbers of lung adenomas in a dose- dependent manner, with the highest dose (6.0 mg/kg) yielding 16.1 adenomas/mouse. In tricaprylin-treated control animals, there were 0.67 adenomas/mouse. Based on the administered dose, DB[a,l]P was more active than other environmental carcinogens including benzo[a]pyrene. As a function of time-integrated DNA adduct levels, DB[a,l]P induced lung adenomas with about the same potency as other PAHs, suggesting that the adducts formed by DB[a,l]P are similar in carcinogenic potency to other PAHs in the strain A/J mouse lung model. Analysis of the Ki- ras mutation spectrum in DB[a,l]P-induced lung tumors revealed the predominant mutations to be G-->T transversions in the first base of codon 12, A-->G transitions in the second base of codon 12, and A-->T transversions in the second or third base of codon 61, concordant with the DNA adduct profile.      

Comparison of the morphological transforming activities of dibenzo[a,l]pyrene and benzo[a]pyrene in C3H10T1/2CL8 cells and characterization of the dibenzo[a,l]pyrene-DNA adducts

C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts were used to study the in vitro carcinogenic activities of dibenzo[a,l]pyrene (DB[a,l]P) and benzo[a]pyrene (B[a]P). The morphological transforming activities of these rodent carcinogens were compared using replicate concentration- response studies. In concentration ranges where both polycyclic aromatic hydrocarbons (PAHs) were active, DB[a,l]P proved to be four to 12 times as potent as B[a]P based on concentration. At lower concentrations DB[a,l]P was active at 0.10 and 0.20 microM, concentrations where B[a]P was inactive. This makes DB[a,l]P the most potent non-methylated PAH evaluated to date in C3H10T1/2 cells. DNA adducts of DB[a,l]P in C3H10T1/2 cells were analyzed by both TLC and TLC/HPLC 32P-postlabeling methods using mononucleotide 3'-phosphate adduct standards derived from the reactions of anti-DB[a,l]P-11,12-diol- 13,14-epoxide (anti-DB[a,l]PDE) and syn-DB[a,l]P-11,12-diol-13,14- epoxide (syn-DB[a,l]PDE) with deoxyadenosine 3'-monophosphate and deoxyguanosine 3'-monophosphate. All of the DNA adducts observed in C3H10T1/2 cells treated with DB[a,l]P were identified as being derived from the metabolism of DB[a,l]P to its fjord region diol epoxides through DB[a,l]P-11,12-diol. The predominant adduct was identified as an anti-DB[a,l]PDE-deoxyadenosine adduct. Other major adducts were anti- DB[a,l]PDE-deoxyguanosine and syn-DB[a,l]PDE-deoxyadenosine adducts with minor amounts of syn-DB[a,l]PDE-deoxyguanosine adducts. These DNA adduct data are consistent with similar findings of DB[a,l]PDE- deoxyadenosine adducts in mouse skin studies and human mammary cells in culture.