Effects of Carbonation and Temperature on Voluntary Swallowing in Healthy Humans.

We investigated how swallowing behaviors are affected by the temperature and carbonation of water in healthy humans. Twenty-nine healthy volunteers were instructed to drink as much natural water, carbonated water, or cider as they wanted, and we recorded the volume of solution swallowed and electromyographic (EMG) activity of the masseter and suprahyoid muscles. Sensory tests regarding the ease of holding the solution in the mouth and ease of swallowing were also performed. The volume of carbonated water swallowed was significantly lower than that of natural water and cider. The ease of holding and swallowing the solution significantly differed between solution types such that natural water was the easiest solution to hold and swallow, followed by cider and then carbonated water in both tests. EMG activity was also affected by the solution type. Masseter EMG activity was significantly lower when swallowing natural water compared with carbonated water. Suprahyoid EMG activity was significantly lower when swallowing natural water compared with carbonated water and cider. The volume of solution swallowed was significantly correlated with the ease of holding and swallowing the solution, but not with masseter or suprahyoid EMG activities. The ease of holding and swallowing the solution significantly affected masseter and suprahyoid EMG activities. The results suggested that when participants experienced difficulty holding and swallowing the solution, masseter and suprahyoid EMG activity increased. Considering our findings that mechanical stimulation with bubbles decreased the volume of solution swallowed and increased EMG activities, carbonated water swallowing may be useful in treating deglutition disorders.

Delayed and acute hemolytic transfusion reactions resulting from red cell antibodies and red cell-reactive HLA antibodies.

BACKGROUND: It has been controversial whether HLA antibodies cause hemolytic transfusion reactions (HTR) or shortened red blood cell (RBC) survival. A patient is reported who had two episodes of HTR, the latter of which was likely due to RBC-reactive HLA antibodies. CASE REPORT: A 77-year-old woman, admitted for gastric varix rupture, had no RBC-irregular antibodies detected before transfusion. On Hospital Day 12, after transfusion of 2 units of RBCs and 2 units of fresh-frozen plasma, the first delayed hemolytic episode occurred and anti-E, anti-c, anti-Jk(a), and unidentified RBC-reactive antibodies were detected in a serum sample from Day 14. Two additional units of matched RBCs were transfused with a leukoreduction filter on Days 19 and 22. After 4 hours of starting a transfusion on Day 22, the patient had fever, and a second hemolytic episode was recorded. Multireactive HLA antibodies (reactive against 20 of 20 donor panel lymphocytes) were detected in serum samples from Day 15 to Day 21. These HLA antibodies reacted strongly with HLA-A2 and HLA-B7 antigens, corresponding to Bg(c) and Bg(a) antigens on RBCs, respectively. RBCs transfused on Day 22 were found to be HLA-A2 by genotyping. CONCLUSION: Strong HLA alloantibodies in this recipient appear to have caused a HTR. It is suggested that HLA antibodies be considered in patients with unexplained HTRs.

Evolution in the hypervariable region of the hepatitis C virus in two infants infected by mother-to-infant transmission.

BACKGROUND: There is little data on the evolution of hepatitis C virus (HCV) quasispecies in infants infected by mother-to-infant transmission during long-term follow up. The hypervariable region 1 (HVR1) of the HCV genome was investigated in two mother-infant pairs from birth to 7.6 and 10.2 years, respectively. METHODS: Ten cDNA clones of HVR1 generated from HCV-RNA and extracted from serum samples of both pairs were analyzed. The sequences were compared with regard to variability, identity, and hydrophobia profile, and analyzed by phylogenetic studies. RESULTS: The alanine aminotransferase (ALT) level was high with fluctuation in infant A and almost within the normal range in infant B. Sequence diversity was higher in infant A at 7.6 years than in infant B at 9.3 years (sequence identity with the mothers'; 69.3-70.7% vs 85.3-90.7% for nucleotides, and 48% vs 68-72% for amino acids, respectively). Compared to the first samples, amino acid changes greatly increased in infant A (35.2% at 4.9 years and 52% at 7.6 years), but not in infant B (4% at 5.6 years and 27.5% at 9.3 years). Phylogenetic studies revealed that quasispecies in infant A evolved to a greater extent than that in infant B. Hydrophobia profile analyses revealed that dynamic shifts between hydrophilia and hydrophobia occurred in both infants. CONCLUSIONS: As in adults, the evolution of HVR1 and variability of quasispecies increased in infants infected through mother-to-infant transmission for 10 years after birth. A large episode of ALT elevation suggested the emergence of escape mutants and the evolution of new quasispecies.

TT virus infection during childhood.

BACKGROUND: TT virus (TTV) is widespread in the general population, however, the mode of its transmission and the mechanism of maintaining it in the general population are unclear. STUDY DESIGN AND METHODS: To determine the possible mother-to-infant route of transmission, 54 infants bom to 50 anti-HCV-positive mothers were assessed longitudinally. Nucleotide sequences amplified by seminested PCR with primers targeting the N22 variable coding region of genotypes 1 through 6 were compared in mothers and their infants. RESULTS: The prevalence of TTV DNA was 30 percent (15/50; 95% CI, 18-45) in mothers and 44 percent (24/54; 95% CI, 31-59) in their infants. TTV DNA was detected during a follow-up period in 13 (87%; 95% CI, 60-98) of 15 infants born to infected mothers and in 11 (28%; 95% CI, 15-45) of 39 infants bom to DNA-negative mothers. None of 38 cord blood samples, but one of 14 blood samples, obtained at 1 month of age had detectable TTV DNA. The lowest infection rate at the earliest ages and the subsequent increasing prevalence of infection (22% at 6 months and 33% [43% cumulative rate] at 2 years) is consistent with an age-dependent acquisition of TTV by nonparenteral routes. In 13-mother-infant pairs positive for TTV DNA, six showed a high degree of nucleotide sequence similarity (99.1-100%), whereas the remaining seven pairs differed more than 10 percent from each other (46.8-89.2%). The viral load of matemal blood was not a plausible risk factor for transmission. Genotype 1, of which pathogenicity failed to be shown by measurement of hepatic enzymes, was more rapidly cleared (88 vs. 8% other genotypes, p < 0.001) among infants. CONCLUSIONS: These observations strongly suggest that the main factor for TTV acquisition in children involves their age-associated increase in environmental interactions with infectious materials. Genotype 1 might be involved in a weak or a limited pathologic role, which can possibly be diluted by other harmless genotypes.