Stability of the m.8993T->G mtDNA mutation load during human embryofetal development has implications for the feasibility of prenatal diagnosis in NARP syndrome

Background

Mitochondrial DNA (mtDNA) mutations cause a wide range of serious genetic diseases with maternal inheritance. Because of the high transmission risk and the absence of therapy in these disorders, at‐risk couples often ask for prenatal diagnosis (PND). However, because heteroplasmy load (coexistence of mutant and wild‐type mtDNA) may vary among tissues and with time, the possibility that a single fetal sample may not reflect the whole neonate impedes prenatal diagnosis of mtDNA diseases.

Methods

We performed 13 prenatal diagnoses for the NARP (neurogenic weakness, ataxia, retinitis pigmentosa) m.8993T→G mtDNA mutation (p.Leu156Arg) in the ATP synthase subunit 6 gene. Analyses were performed on chorionic villous (CVS) and/or amniocyte samples carried out at various stages of pregnancy, using a method enabling quantification of low DNA amounts.

Results

Maternal mutant loads ranged from 0 to 75% in blood and had no predictive value for the fetus status, except for women with no detectable mutant DNA, whose fetuses were consistently mutation‐free. In 8/13 PND, mutant load was <30%. These children are healthy at 2–7 years of age. In 5/13 PND, mutant load ranged from 65 to 100%, and parents preferred to terminate the pregnancies (15–22 weeks of gestation). Single‐cell analysis of 20 trophoblastic cells and 21 amniocytes isolated from two affected fetuses found an average mutant load close to the overall CVS and amniocyte mutant load, despite striking intercellular variation. The m.8993T→G mutant loads, assessed in 7, 17, 11, and 5 different tissues from 4 terminations, respectively, were identical in all tissues from a given individual (mean (SD) 78 (1.2)%, 91 (0.7)%, 74 (2)%, and 63 (1.6)% for the 4 fetuses, respectively).

Conclusions

Our results indicate that the placental/amniotic mutant loads do reflect the NARP mutant mtDNA load in the whole fetus, even when the sample amount is small, and suggest that heteroplasmy level remains stable during pregnancy, at least after 10 weeks of gestation. Although these data establish the feasibility of PND for this mutation, assessing more precisely the correlation between mutant load and disease severity should further help in interpreting PND results.     

Plasma-exchange in immunologically mediated glomerular diseases

International Journal of Clinical and Laboratory Research - Intensive plasma-exchange, usually combined with steroids and cyclophosphamide, was carried out in 10 patients with rapidly progressive...     

Penetration enhancer containing vesicles as carriers for dermal delivery of tretinoin

The ability of a recently developed novel class of liposomes to promote dermal delivery of tretinoin (TRA) was evaluated. New penetration enhancer-containing vesicles (PEVs) were prepared adding to conventional phosphatidylcholine vesicles (control liposomes) different hydrophilic penetration enhancers: Oramix NS10 (OrNS10), Labrasol (Lab), Transcutol P (Trc), and propylene glycol (PG). Vesicles were characterized by morphology, size distribution, zeta potential, incorporation efficiency, stability, rheological behaviour, and deformability. Small, negatively charged, non-deformable, multilamellar vesicles were obtained. Rheological studies showed that PEVs had fluidity higher than conventional liposomes. The influence of the obtained PEVs on (trans)dermal delivery of tretinoin was studied by ex vivo diffusion experiments through new born pig skin using formulations having the drug both inside and outside the vesicles, having TRA only inside, in comparison with non-incorporated drug dispersions of the same composition used to produce the studied vesicles. Main result of these experiments was an improved cutaneous drug accumulation and a reduced transdermal TRA delivery (except for PG-PEVs). TRA deposition provided by PEVs was higher for dialysed than for non-dialysed vesicles. Further, the accumulation increased in the order: control liposomes相似文献   

Antinucleosome antibodies in primary antiphospholipid syndrome: a hint at systemic autoimmunity?

BACKGROUND: Antinucleosome antibodies (anti-NCS) are reported to be highly sensitive and specific for systemic lupus erythematosus (SLE) and to correlate with disease activity. They may appear in early stages of the disease, in particular before anti-dsDNA antibodies, being a potential marker for identifying patients susceptible to SLE. Patients with primary antiphospholipid syndrome (PAPS) may develop full-blown SLE but there is no evidence for markers predictive for that. AIM: To evaluate whether anti-NCS may be predictors for full-blown or lupus like disease (LL) in a cohort of PAPS patients. METHODS: A multicentric cohort of 105 PAPS patients was tested for IgG/IgM anti-NCS by using a home made assay with H1-stripped chromatin as antigen. RESULTS: Eighty-one out of 105 (77%) of the patients were positive for anti-NCS; medium-high titre results were present only in 49/105 (46%). Anti-NCS were more frequently detected in PAPS+LL, but no relationship with clinical/serological features was found, except for a weak correlation with anti-dsDNA antibodies. Two PAPS patients evolved into full-blown SLE during the follow-up and displayed high titre anti-NCS many years before. CONCLUSIONS: Our findings suggest that anti-NCS might be added to the mosaic of autoimmune phenomena characterizing PAPS patients and in particular those with more chance to evolve to SLE.     

Presence of papilloma virus type 11 in condyloma acuminatum of bladder in female renal transplant recipient

A case is reported of a female renal transplant recipient in whom, after two years of immunosuppression, condylomata acuminata of the genital tract with urethral and bladder extension developed. The condyloma of the bladder was resected endoscopically with no relapse. Virologic examination revealed a human papilloma virus type 11.     

Experimental autoimmune glomerulonephritis induced by homologous and isologous glomerular basement membrane in Brown-Norway rats

In order to study disease mechanisms and potential forms of therapy in glomerulonephritis, a model of experimental autoimmune glomerulonephritis (EAG) has been developed in the rat. We have examined the response of Brown-Norway (BN) rats to a single i.m. injection of collagenase-solubilised homologous (Sprague-Dawley, SD) or isologous (BN) glomerular basement membrane (GBM), with and without complete Freund's adjuvant (CFA). There was a dose-dependent circulating anti-GBM antibody response to all preparations of rat GBM. Animals given either antigen alone at a dose of 2 mg/kg developed circulating anti-GBM antibodies, which reached peak values by 6 weeks (63 +/- 5% following SD GBM; 53 +/- 8% following BN GBM), but did not develop glomerular deposits of IgG or nephritis. Animals given 2 mg/kg SD GBM in CFA developed greater concentrations of anti-GBM antibody by 6 weeks (122 +/- 20%) together with linear deposits of IgG on glomerular and tubular basement membranes (TBM), albuminuria (mean 7 mg/24 h), and variable focal segmental necrotising glomerulonephritis with mild interstitial nephritis. The same dose of BN GBM in CFA produced similar concentrations of circulating antibody (144 +/- 26%), with linear deposits of IgG on GBM but rarely TBM, little albuminuria, and variable mild focal glomerulonephritis. Other strains injected with SD GBM in CFA showed a variable circulating anti-GBM antibody response, which was similar to that of BN rats in PVG and DA rats but lower in LEW and WAG rats. Linear deposits of IgG on the GBM were detected in a proportion of PVG and DA rats, but not in LEW or WAG rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hepatoblastoma and hepatocarcinoma in children: analysis of a series of 29 cases

Twenty-nine cases of liver malignancies, 26 hepatoblastomas (HB) and 3 hepatocarcinomas (HC), were treated in a 13-year period. All children were submitted to operation but four had nonresectable tumors, even after chemotherapy. Surgery in the 25 cases consisted of right lobectomy in 14, a left lobectomy in 9, and a tumorectomy in 2; a secondary operation had to be performed in 5 cases, either because of histologic doubt on the cut section of the presumed normal parenchyma, or for local recurrence. Preoperative chemotherapy, instituted on a routine basis since 1982, did appear to facilitate surgery in otherwise inoperable tumors. The benefits of preoperative embolization, done for three children, were minimal. Ten children died, one in the immediate postoperative period, eight others from the disease, and one from a complication of chemotherapy. Follow-up for the 18 surviving children, all recurrence and metastasis-free, with normal alphafetoprotein (AFP) is less than 2 years for four and from 2 to 11 years for 14. One teen-age girl, with a fibrolamellar carcinoma has just recently been reoperated because of recurrence three years later. In spite of the fact that 6 out of 7 children operated without adjunctive treatment are cured, a systematic course of preoperative chemotherapy has been prescribed in the more recent cases. Follow-up for these is yet too short.     

Increased serum levels of IgA1-IgG immune complexes and anti-F(ab')2 antibodies in patients with primary IgA nephropathy

A solid-phase ELISA was used to detect IgA1 immune complexes (IgA1 ICs) containing IgG and IgM in 38 serum samples from 30 patients with primary IgA nephropathy (IgAN) and 14 subjects with non-IgA chronic glomerulonephritis. A jackfruit lectin, jacalin, was used as the substrate for the selective binding of human IgA1 ICs in serum PEG precipitate (7%). The presence of IgG, A and M antibodies against the F(ab')2 region of IgG was also investigated by the solid-phase ELISA. Six patients were studied during remission and relapse (fever, upper respiratory tract infection and macroheamaturia). The results showed significant increases in serum levels of IgA1 ICs (P less than 0.001) in 39.4% of the IgAN patients, IgA1-IgG ICs (P less than 0.001) in 68.4%, and IgA1-IgM ICs (P less than 0.002) in 10.5% of the patients. A significant increase in IgA1-IgG ICs was observed during relapse (P less than 0.02). Significantly high values of IgG (P less than 0.003) and IgA (P less than 0.001) antibodies directed at the F(ab')2 region of IgG were found. A significant increase in anti F(ab')2 antibodies (class IgA and IgM) was seen in the acute phase of the disease. The data suggest that an increased production of IgA1 ICs occurs in IgAN patients; ICs are mainly IgA1-IgG ICs during relapse. The presence of high serum levels of IgG and IgA antibodies against the F(ab')2 region of IgG indicates that in addition to the multiple anomalies of IgA regulation described in IgAN patients there may be further aberrances.