Screening for carriers of Tay-Sachs disease among Ashkenazi Jews. A comparison of DNA-based and enzyme-based tests

BACKGROUND AND METHODS. The prevention of Tay-Sachs disease (GM2 gangliosidosis, type 1) depends on the identification of carriers of the gene for this autosomal recessive disorder. We compared the enzyme-based test widely used in screening for Tay-Sachs disease with a test based on analysis of DNA. We developed methods to detect the three mutations in the HEXA gene that occur with high frequency among Ashkenazi Jews: two mutations cause infantile Tay-Sachs disease, and the third causes the adult-onset form of the disease. DNA segments containing these mutation sites were amplified with the polymerase chain reaction and analyzed for the presence of the mutations. RESULTS. Among 62 Ashkenazi obligate carriers of Tay-Sachs disease, the three specific mutations accounted for all but one of the mutant alleles (98 percent). In 216 Ashkenazi carriers identified by the enzyme test, DNA analysis showed that 177 (82 percent) had one of the identified mutations. Of the 177, 79 percent had the exon 11 insertion mutation, 18 percent had the intron 12 splice-junction mutation, and 3 percent had the less severe exon 7 mutation associated with adult-onset disease. The results of the enzyme tests in the 39 subjects (18 percent) who were defined as carriers but in whom DNA analysis did not identify a mutant allele were probably false positive (although there remains some possibility of unidentified mutations). In addition, of 152 persons defined as noncarriers by the enzyme-based test, 1 was identified as a carrier by DNA analysis (i.e., a false negative enzyme-test result). CONCLUSIONS. The increased specificity and predictive value of the DNA-based test make it a useful adjunct to the diagnostic tests currently used to screen for carriers of Tay-Sachs disease. Although some false positive results may be desirable on an enzyme-based test that is used in screening, the DNA test allows precise definition of the carrier state for the known mutations.     

METHODS FOR ESTIMATION OF BLOOD GLUCOSE : A COMPARATIVE EVALUATION

Glucose in blood is the most frequent analyzed parameter in a clinical chemistry laboratory. In Armed Forces Laboratories, copper reduction method (Modified Folin Wu) is commonly used. Here we have compared this method as well as O-Toluidine and GOD-POD method with reference UV-Hexokinase method. Both Modified Folin Wu and O-Toluidine showed upward deviation with substantial imprecision (CV=4.9% – 3.5% and 6% – 5.8% respectively) and inaccuracy (Average deviation = 5.76% and 10.68% respectively). GOD-POD method was found linear (up to 500 mg/dl), with good precision (CV=0.7% to 1.4%) and accuracy (Average deviation= −0.97%). This method is simple, rapid, economical and sensitive, and can be adopted to a routine colorimeter.KEYWORDS: Blood glucose, Diabetes mellitus, Glucose oxidase     

应用Sihler氏染色研究人喉神经分支分布类型

采用Sihler氏染色,经过染色后,在立体显微解剖镜下、可清晰地观察到喉内肌肌肉神经支配类型及神经间的联系,结果:(1)喉返神经支配除环甲肌以外的所有喉内肌,环甲肌由喉上神经外支支配.(2)喉上神经内支不仅支配声门上粘膜,也支配杓间肌(包括的横肌和杓斜肌)和声门下粘膜.(3)在每侧杓间肌肉.喉返神经和喉上神经内支之间百多个吻合支.(4)喉返神经的杓间肌神经和环杓后肌神经之间常有交通支.     

Sustained Recreational Use of Ecstasy Is Associated with Altered Pre and Postsynaptic Markers of Serotonin Transmission in Neocortical Areas: A PET Study with [11C]DASB and [11C]MDL 100907

3,4-Methylenedioxymethamphetamine (MDMA), the main psychoactive component of the recreational drug ecstasy, is a potent serotonin (5-HT) releaser. In animals, MDMA induces 5-HT depletion and toxicity in 5-HT neurons. The aim of this study was to investigate both presynaptic (5-HT transporter, SERT) and postsynaptic (5-HT_2A receptor) markers of 5-HT transmission in recently abstinent chronic MDMA users compared with matched healthy controls. We hypothesized that MDMA use is associated with lower SERT density and concomitant upregulation of 5-HT_2A receptors. Positron emission tomography studies using the SERT ligand [¹¹C]DASB and the 5-HT_2A receptor ligand [¹¹C]MDL 100907 were evaluated in 13 current and recently detoxified MDMA users and 13 matched healthy controls. MDMA users reported a mean duration of ecstasy use of 8 years, regular exposure, and at least 2 weeks of abstinence before the scans. SERT and 5-HT_2A receptor availability (binding potential, BP_ND) were analyzed with a two-tissue compartment model with arterial input function. Current recreational MDMA use was significantly associated with lower SERT BP_ND and higher 5-HT_2A receptor BP_ND in cortical, but not subcortical regions. Decreased SERT BP_ND was regionally associated with upregulated 5-HT_2A receptor BP_ND. In light of the animal literature, the most parsimonious interpretation is that repeated exposure to MDMA in humans, even in moderate amounts, leads to damage in 5-HT neuron terminals innervating the cortex. Alterations in mood, cognition, and impulse control associated with these changes might contribute to sustain MDMA use. The reversibility of these changes upon abstinence remains to be firmly established.     

Vitamin D deficiency in Iranian mothers and their neonates: a pilot study

We conducted a pilot study to assess the prevalence of hypovitaminosis D among Iranian women and their newborns. Blood samples were taken from 50 mothers (age 16-40 yr) and their neonates at term delivery in the largest Tehran hospital. The results showed that 80% of the women had 25-hydroxyvitamin D (25-OHD) concentrations of less than 25 nmol/l. Mean maternal plasma calcium and phosphatase alkaline concentrations were in the normal range. The mean maternal serum immunoreactive parathyroid hormone concentration of women with hypovitaminosis D (i.e., 25-OHD levels <25 nmol/l) was above normal range and significantly different from that of women without hypovitaminosis D. CONCLUSION: The mean cord serum 25-OHD concentration was very low (4.94+/-9.4 nmol/l) and that of infants of mother with hypovitaminosis D were almost undetectable (1.2+/-1.2 nmol/l).     

A novel pathogenic MLH1 missense mutation, c.112A > C, p.Asn38His, in six families with Lynch syndrome

Background

An unclassified variant (UV) in exon 1 of the MLH1 gene, c.112A > C, p.Asn38His, was found in six families who meet diagnostic criteria for Lynch syndrome. The pathogenicity of this variant was unknown. We aim to elucidate the pathogenicity of this MLH1 variant in order to counsel these families adequately and to enable predictive testing in healthy at-risk relatives.

Methods

We studied clinical data, microsatellite instability and immunohistochemical staining of MMR proteins, and performed genealogy, haplotype analysis and DNA testing of control samples.

Results

The UV showed co-segregation with the disease in all families. All investigated tumors showed a microsatellite instable pattern. Immunohistochemical data were variable among tested tumors. Three families had a common ancestor and all families originated from the same geographical area in The Netherlands. Haplotype analysis showed a common haplotype in all six families.

Conclusions

We conclude that the MLH1 variant is a pathogenic mutation and genealogy and haplotype analysis results strongly suggest that it is a Dutch founder mutation. Our findings imply that predictive testing can be offered to healthy family members. The immunohistochemical data of MMR protein expression show that interpreting these results in case of a missense mutation should be done with caution.     

Implantable total artificial heart: history and present status at the University of Tokyo

The University of Tokyo has been involved in research and development of the artificial heart since 1959. This paper is a brief review of 40 years of total artificial heart research in the University of Tokyo. Many types of artificial heart and various kinds of materials, blood pumps, valves, drive units, control methods, and pathophysiology have been investigated in our original fashion. The longest survival was 532 days for a goat with a total artificial heart (TAH) placed on the chest wall. These results made us take a step toward the development of an implantable TAH. Two kinds of implantable TAH are now being developed: FTPTAH (flow-transformed pulsatile total artificial heart) and UPTAH (undulation pump total artificial heart). Recently, a goat survived for 31 days with an UPTAH.     

Utility of the low-accelerating-dose regimen in 182 liver recipients with recurrent hepatitis C virus

AIM: To describe our experience using a low-acceleratingdose regimen(LADR) with pegylated interferon alpha-2a and ribavirin in treatment of hepatitis C virus(HCV) recurrence. METHODS: From 2003, a protocolized LADR strategy was employed to treat liver transplant(LT) recipients with recurrent HCV at our institution. Medical records of 182 adult patients with recurrent HCV treated with LADR between 1/2003 and 1/2011 were reviewed. Histopathology from all post-LT liver biopsies were reviewed in a blinded fashion. Paired recipient and donor IL28 B status were assessed. A novel technique was employed to ascertain recipient and donor IL28B(rs12979860) Gt data using DNA extracted from archival FFPE tissue from explanted native livers and donor gallbladders respectively. The primary endpoint was SVR; secondary endpoints examined include(1) patient and graft survival;(2) effect of anti-viral therapy on liver histology(fibrosis and inflammation);(3) incidence of on-treatment development of ACR, CDR, or PCH;(4) association of recipient and donor IL28 B genotype with SVR; and(5) incidence of antiviral therapy-associated adverse events(anemia, leukopenia, thrombocytopenia, depression) and hepatic decompensation.RESULTS: The overall SVR rate was 38%(29% Gt1, 67% Gt2, 86% Gt3 and 58% Gt4). HCV Gt(P 0.0001), donor age(P = 0.003), cytomegalovirus mismatch(P = 0.001), baseline serum bilirubin(P = 0.002), and baseline viral load(P = 0.04) were independent predictors for SVR. SVR rates were significantly higher in the recipient-CC/donor-non CC pairs(P = 0.007). Neither baseline fibrosis nor change in fibrosis stage after anti-viral therapy were associated with SVR. Fibrosis progressed in 72% of patients despite SVR. Median graft survival was 91 mo. Five-year patient survival was superior in patients who achieved SVR(97% vs 82%, P = 0.001). Pre-treatment ALP ≥ 150 U/L(P = 0.01), total bilirubin ≥ 1.5 mg/d L(P = 0.001) and creatinine ≥ 2 mg/d L(P = 0.001) were independently associated with patient survival. Only 13% of patients achieving SVR died during the followup period. Treatment discontinuation and treatmentrelated mortality occurred in 35% and 2.2% of patients, respectively. EPO, G-CSF and blood transfusion were needed in 89%, 40% and 23% of patients, respectively. Overall hospitalization rate for treatment-related serious adverse events was 21%. Forty-six(25%) of the patients were deceased; among those who died, 25(54%) were due to liver-related complications, and 4 deaths(9%) occurred while receiving therapy(2 patients experienced hepatic decompensation and 2 sepsis). CONCLUSION: LADR strategy remains relevant in managing post-LT recurrent HCV where access to DAAs is limited. SVR is associated with improved survival, but fibrosis progression still occurs.