Genotype-phenotype relationship in human ATP6i-dependent autosomal recessive osteopetrosis

Autosomal-recessive osteopetrosis is a severe genetic disease caused by osteoclast failure. Approximately 50% of the patients harbor mutations of the ATP6i gene, encoding for the osteoclast-specific a3 subunit of V-ATPase. We found inactivating ATP6i mutations in four patients, and three of these were novel. Patients shared macrocephaly, growth retardation and optic nerve alteration, osteosclerotic and endobone patterns, and high alkaline phosphatase and parathyroid hormone levels. Bone biopsies revealed primary spongiosa lined with active osteoblasts and high numbers of tartrate-resistant acid phosphatase (TRAP)-positive, a3 subunit-negative, morphologically unremarkable osteoclasts, some of which located in shallow Howship lacunae. Scarce hematopoietic cells and abundant fibrous tissue containing TRAP-positive putative osteoclast precursors were noted. In vitro osteoclasts were a3-negative, morphologically normal, with prominent clear zones and actin rings, and TRAP activity more elevated than in control patients. Podosomes, alphaVbeta3 receptor, c-Src, and PYK2 were unremarkable. Consistent with the finding in the bone biopsies, these cells excavated pits faintly stained with toluidine blue, indicating inefficient bone resorption. Bone marrow transplantation was successful in all patients, and posttransplant osteoclasts showed rescue of a3 subunit immunoreactivity.     

Intravenous immune globulin in lysinuric protein intolerance

In addition to systemic manifestations with skeletal, pulmonary, renal, and haematological signs, lysinuric protein intolerance (LPI), a membrane transport defect of cationic amino acids, is often complicated by severe life-threatening immunological manifestations. A 10-year-old boy with LPI who exhibited a severe systemic immunohaematological disease is described here. This patient showed cutaneous lesions similar to the subacute form of systemic lupus erythematosus, severe anaemia and dysproteinaemia, and a marked reduction of circulating T lymphocytes, mainly the CD4⁺ cells. In vitro bone marrow cell culture studies showed that addition of patient's serum induced macrophage proliferation and inhibited erythroid progenitor cell growth. Treatment with high-dose intravenous immune globulin resolved most of the clinical and laboratory abnormalities.     

Bilirubin protects astrocytes from its own toxicity by inducing up-regulation and translocation of multidrug resistance-associated protein 1 (Mrp1)

Unconjugated bilirubin (UCB) causes encephalopathy in severely jaundiced neonates by damaging astrocytes and neurons. Astrocytes, which help defend the brain against cytotoxic insults, express the ATP-dependent transporter, multidrug resistance-associated protein 1 (Mrp1), which mediates export of organic anions, probably including UCB. We therefore studied whether exposure to UCB affects the expression and intracellular localization of Mrp1 in cultured mouse astroglial cells (>95% astrocytes). Mrp1 was localized and quantitated by confocal laser scanning microscopy and double immunofluorescence labeling by using specific antibodies against Mrp1 and the astrocyte marker glial fibrillary acidic protein, plus the Golgi marker wheat germ agglutinin (WGA). In unexposed astrocytes, Mrp1 colocalized with WGA in the Golgi apparatus. Exposure to UCB at a low unbound concentration (Bf) of 40 nM caused rapid redistribution of Mrp1 from the Golgi throughout the cytoplasm to the plasma membrane, with a peak 5-fold increase in Mrp1 immunofluorescence intensity from 30 to 120 min. Bf above aqueous saturation produced a similar but aborted response. Exposure to this higher Bf for 16 h markedly decreased Trypan blue exclusion and methylthiazoletetrazoilum activity and increased apoptosis 5-fold by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay. These toxic effects were modestly increased by inhibition of Mrp1 activity with 3-([3-(2-[7-chloro-2-quinolinyl]ethenyl)phenyl-(3-dimethylamino-3-oxopropyl)-thio-methyl]thio)propanoic acid (MK571). By contrast, Bf=40 nM caused injury only if Mrp1 activity was inhibited by MK571, which also blocked translocation of Mrp1. Our conclusion is that in astrocytes, UCB up-regulates expression of Mrp1 and promotes its trafficking from the Golgi to the plasma membrane, thus moderating cytotoxicity from UCB, presumably by limiting its intracellular accumulation.     

Perioperative outcomes of laparoscopic and robot-assisted major hepatectomies: an Italian multi-institutional comparative study

Background

Laparoscopic major hepatectomy (LMH), although safely feasible in experienced hands and in selected patients, is a formidable challenge because of the technical demands of controlling hemorrhage, sealing bile ducts, avoiding gas embolism, and maintaining oncologic surgical principles. The enhanced surgical dexterity offered by robotic assistance could improve feasibility and/or safety of minimally invasive major hepatectomy. The aim of this study was to compare perioperative outcomes of LMH and robotic-assisted major hepatectomy (RMH).

Methods

Pooled data from four Italian hepatobiliary centers were analyzed retrospectively. Demographic data, operative, and postoperative outcomes were collected from prospectively maintained databases and compared.

Results

Between January 2009 and December 2012, 25 patients underwent LMH and 25 RMH. The two groups were comparable for all baseline characteristics including type of resection and underlying pathology. Conversion to open surgery was required in one patient in each group (4 %). No difference was noted in operative time, estimated blood, and need for allogenic blood transfusions. Intermittent pedicle occlusion was required only in LMH (32 % vs. 0; p = 0.004). Length of hospital stay, including time spent in intensive care unit, was similar between the two groups, but patients undergoing LMH showed quicker recovery of bowel activity, with shorter time to first flatus (1 vs. 3 days; p = 0.023) and earlier tolerance to oral liquid diet (1 vs. 2 days; p = 0.001). No difference was noted in complication rate, 90-day mortality, and readmission rate.

Conclusions

This retrospective multi-institution study confirms that selected patients can safely undergo minimally invasive major hepatectomy, either LMH or RMH. The fact that intermittent pedicle occlusion could be avoided in RMH suggests improved surgical ability to deal with bleeding during liver transection, but further studies are needed before any final conclusion can be drawn.     

Longitudinal study of 94 symptomatic infants with perinatally acquired human immunodeficiency virus infection. Evidence for a bimodal expression of clinical and biological symptoms

To better define the clinical and biological evolution of infants after vertical human immunodeficiency virus type 1 infection, we analyzed 94 consecutive infected patients followed up after their first clinical symptoms. The expression of clinical symptoms and biological abnormalities followed a bimodal distribution, some patients having an early and severe disease and the others having a slowly progressive one. One third of our patients suffered from early onset of opportunistic infection (OI). These patients had a significantly higher incidence of severe encephalopathy compared with patients without OI. The rate of survival at 3 years was 48% +/- 24%. In contrast, the patients without early OI or severe encephalopathy had a probability of survival at 3 years of 97% +/- 3%. This probability was not modified by the occurrence of bacterial infection or lymphoid interstitial pneumonitis. Lymphoid interstitial pneumonitis occurred at a mean age of 29 months, significantly later than OI or severe encephalopathy. Laboratory results at initial examination were correlated with clinical symptoms. Thus, when the number of CD4 lymphocytes was less than 500/mm3, children suffered more frequently from life-threatening symptoms (OI and severe encephalopathy): 15 of 22 vs 14 of 69. The same was true when the lymphocytes did not proliferate after antigenic stimulation, when anti-p18 and/or anti-p25 antibodies were absent in the serum, and when p24 antigen was detected in serum. Finally, severe encephalopathy was associated with low anti-human immunodeficiency virus cerebrospinal fluid antibody titer, whereas 88% of patients with moderate or no encephalopathy had signs of intrathecal anti-human immunodeficiency virus antibody synthesis. In conclusion, a subgroup of patients expressed very early signs of severe immunodeficiency and encephalopathy, whereas the majority of patients had a longer survival and less severe clinical symptoms during their first years of life than previously thought.     

Immunohistochemical and molecular study of radiation-induced multiple meningiomas with pleural and pulmonary metastasis

In the present study, the telomerase activity and the putative alterations of genes involved in cell-cycle control (p53, Fas and pRb) were investigated in a radiation-induced meningioma with multiple recurrences and pleural-pulmonary metastases (the patient, a 34-year-old male, had a history of carcinoma of the tongue of testicular lymphocytic lymphoma). Expression of VEGF and vasculature pattern were also studied. Expression of VEGF, pRb and p53 were evaluated by immunohistochemistry on formalin-fixed, paraffin-embedded samples of the tumor. VEGFmRNA was determined by competitive PCR. Fas, FasL and hTERT were evaluated by RT-PCR. Telomerase activity was examined by the TRAP assay. An intense vascularization was observed, supported by high expression of VEGFmRNA (isoforms 121 and 165). pRb and p53 were overexpressed. Fas was undetectable with PCR, whereas FasL was positive. Furthermore, the lesion showed an elevated telomerase activity (TPG, 22), according to the high expression of hTERT. These findings emphasized that even among generally benign neoplasms, such as meningiomas, some highly malignant tumors may develop, as in our case, in which several mechanisms were activated in the cancer progression to guarantee the immortalization of cellular clones (angiogenic phenomenon, activation of telomerase and of anti-apoptotic mechanisms) and the blood spread. Thus, the data illustrate the importance of searching for genetic aberrations (which are a hallmark of malignancy) in meningiomas, as predictive and reliable factors of the possibility to recur and to metastasize.     

X-linked thrombocytopenia and Wiskott-Aldrich syndrome: similar regional assignment but distinct X-inactivation pattern in carriers

While inherited X-linked (XL) isolated thrombocytopenia is a mild condition, the Wiskott-Aldrich syndrome (WAS) associates severe thrombocytopenia with an immunodeficiency component and has a poor prognosis. Whether these conditions correspond to separate genetic entities or to different mutations of the same gene(s) remains unresolved. The Wiskott-Aldrich syndrome locus has been assigned to Xp 11.2 by means of RFLP studies. The X-inactivation pattern in female carriers has been found to follow a skewed pattern in the hematopoietic cells, thus allowing carrier detection. We studied a family with four members affected by XL thrombocytopenia and report the results of genetic segregation analysis, together with the X-inactivation pattern of hematopoietic cells from an obligate female carrier. Although the affected locus mapped to the same region as that of WAS, lymphocytes presented a skewed pattern of X-inactivation, whereas polymorphonuclear lymphocytes (PMN) did not. These results provide further evidence that the Wiskott-Aldrich syndrome and XL thrombocytopenia are different expressions of mutations within a single locus and that the severity of the disease corresponds to distinct hematopoietic cell selections in obligate carriers.