Semi-solid albumin solder improved mechanical properties for laser tissue welding.

BACKGROUND AND OBJECTIVE: A semi-solid albumin solder formulated with hydroxypropylmethylcellulose (HPMC) was designed to improve the characteristics of liquid and solid solders. STUDY DESIGN/MATERIALS AND METHODS: Acute tensile strengths were determined on canine small bowel in vitro by using liquid 50% bovine serum albumin (BSA), semi-solid 48% BSA with HPMC, and solid 60% BSA solder. Long-term healing of liquid and semi-solid solders, compared with a suture control, was evaluated in a porcine skin model, with tensile strength as well as histologic findings obtained on postoperative day 7. RESULTS: Acutely, semi-solid solder demonstrated a significantly (P < 0.05) higher tensile strength when compared with liquid or solid solder. At 7 days, HSA semi-solid and BSA semi-solid had significantly (P < 0.05) higher tensile strength than suture control; however, no differences were seen for liquid or solid solder groups. No differences in histology were appreciable between any of the solder groups in a porcine skin model. CONCLUSION: Acutely and at 7 days, semi-solid solder was stronger than 50% liquid albumin with better handling characteristics.

Are the cytokines interleukin-6 and angiogenin stable in frozen amniotic fluid?

OBJECTIVE: To determine the stability of cytokines in frozen stored amniotic fluid samples, we measured angiogenin, a potent inducer of neovascularization and interleukin-6, an inflammatory cytokine, in the same sample of midtrimester amniotic fluid 1 year apart. STUDY DESIGN: In this study paired aliquots of amniotic fluid kept at -70 degrees C were immunoassayed for angiogenin and interleukin-6 at two different time periods 1 year apart. Inclusion criteria were (1) samples with clearly identifiable numbers, (2) no evidence of breaks in sealing of samples, and (3) singleton gestation. Amniotic fluid was immunoassayed for angiogenin and interleukin-6 in July 1995 and 1996. Angiogenin sensitivities were 0.078 and 0.026 ng/ml, interassay coefficients of variation were 3.8% and 4.6%, and intraassay coefficients of variation were 2.7% and 2.9%, respectively, in 1995 and 1996. Interleukin-6 sensitivities were 1.74 and 2.37 pg/ml, interassay coefficients of variation were 8.9% and 2.6%, and intraassay coefficients of variation were 3.5% and 1.9%, respectively, in 1995 and 1996. Statistical analysis included paired t test, Wilcoxon signed-rank test, and regression with p < 0.05 significant. Angiogenin and interleukin-6 values were normalized with natural log transformation for statistical analysis. RESULTS: Paired amniotic fluid samples from 30 patients were immunoassayed from 1993 to 1995. The values of angiogenin were significantly lower in the 1996 assay compared with the 1995 assay (median 12.4 [range 5.6 to 61.3] vs 26.7 [range 13.6 to 159.2] ng/ml, p < 0.001). A significant correlation was found between the change in angiogenin levels and the year of the sample, with older samples having the greatest change in values (r=0.5, p=0.008). The values of interleukin-6 were significantly lower in the 1996 assay compared with the 1995 assay (median 230.8 [range 40.9 to 3711.3] vs 289.2 [range 53.7 to 19100.0] pg/ml, p < 0.001). CONCLUSIONS: Angiogenin and interleukin-6 values in amniotic fluid appear to decrease with time despite optimal freezing conditions. The year of sampling and length of storage should be taken into consideration when evaluating amniotic fluid cytokine levels from stored samples.

Is maternal serum triple screening a better predictor of Down syndrome in female than in male fetuses?

Among euploid gestations, female fetuses have been reported to have significantly lower maternal serum alpha-fetoprotein (MSAFP) and higher human chorionic gonadotropin (hCG) levels than male fetuses. Since in maternal serum triple screening, low MSAFP and high hCG MOM independently confer greater risk of a Down syndrome fetus, we investigated the hypothesis that maternal serum triple screening is more efficacious at detecting female than male Down syndrome fetuses. A database containing all karyotypes from amniocentesis performed between August 1994 and August 1996 was accessed. All trisomy 21 cases were identified. The male-to-female ratio among trisomy 21 fetuses detected at amniocentesis after abnormal maternal serum triple screening was compared with that among trisomy 21 fetuses detected at amniocentesis for advanced maternal age (AMA), which served as the control group. Statistical analysis utilized chi-square, Fisher's exact test, and Student's t-test. A P value of less than 0.05 was considered statistically significant. Forty-nine trisomy 21 fetuses were detected in the women who underwent amniocentesis because of abnormal triple screening and 311 were detected in the control group. The proportion of male fetuses among the triple screening group was not significantly different from that of the AMA group (55 per cent vs. 57 per cent; P=0.9). Our study had a power of 80 per cent to detect a difference of 25 per cent in the male-to-female ratio (alpha=0.05, beta=0.20). The reported differences in MSAFP and hCG levels between male and female euploid fetuses do not appear to affect the sex ratio among Down syndrome fetuses detected because of an abnormal maternal serum triple screening.

Elevated maternal serum midtrimester alpha-fetoprotein levels are associated with fetoplacental ischemia.

OBJECTIVE: Elevation of maternal serum alpha-fetoprotein in the second trimester is associated with poor pregnancy outcome, including fetal death, preterm delivery, and fetal growth restriction. We hypothesized that placental ischemia may be the common underlying pathogenesis of these outcomes. Thus we tested angiogenin, a potent inducer of neovascularization, in midtrimester amniotic fluid of patients with elevated maternal serum alpha-fetoprotein values to determine whether alpha-fetoprotein elevation is due to ischemia with subsequent stimulation of angiogenesis. STUDY DESIGN: In this case-control study, patients with elevated maternal serum alpha-fetoprotein levels (> or = 2.0 multiples of the median, n = 9) at triple screen were matched with two controls (n = 18) on the basis of year of amniocentesis and maternal age, race, and parity. The median elevation of maternal serum alpha-fetoprotein in the study population was 4.01 multiples of the median (range 2.65 to 7.24 multiples of the median). Inclusion criteria were (1) singleton gestation, (2) no evidence of fetal structural or chromosomal anomalies, and (3) genetic amniocentesis. Amniotic fluid was immunoassayed for angiogenin (Quantikine, R&D Systems; sensitivity 0.026 ng/ml, interassay and intraassay coefficients of variation 4.6% and 2.9%, respectively). Statistical analysis included one-way analysis of variance and regression with p < 0.05 significant. Angiogenin and maternal serum alpha-fetoprotein values were normalized with use of natural log transformation for statistical analysis. RESULTS: Angiogenin values were significantly elevated in patients with high maternal serum alpha-fetoprotein levels (median 31.1 [range 9.2 to 54.6] vs 17.1 [range 9.0 to 29.2] ng/ml, p = 0.02). Mean gestational age at sampling, maternal age, and year of amniocentesis were not significantly different between the study and control groups (each p > 0.05). As anticipated, there was a significant increase in preterm deliveries and small-for-gestational-age neonates in the patients with elevated maternal serum alpha-fetoprotein levels (each p < 0.01). CONCLUSIONS: Midtrimester amniotic fluid angiogenin levels are significantly elevated in patients with elevated midtrimester maternal serum alpha-fetoprotein levels. Because angiogenin is a known marker of tissue ischemia, resulting in neovascularization, we hypothesize that elevation of maternal serum alpha-fetoprotein levels at triple screen is due to placental ischemia.

Perception of syllable stress in esophageal speech.

This study is part of a larger investigation designed to assess the ability of esophageal speakers to effect systematic changes in listener perceptions of syllable stress. Ten male functional esophageal speakers and ten normal speakers were instructed to produce 25 repetitions of the disyllable/mama/ using five different conditions of syllable stress, ranging from strong first syllable stress through strong second syllable stress. Nine normal listeners judged both relative and absolute syllable stress of the disyllables, using a nine-point scale for each syllable. The results indicated that highly reliable judgments can be made when judging relative and absolute syllable stress in disyllables produced by both normal and esophageal speakers. In response to experimenter direction, both normal and esophageal speakers are able to effect systematic changes of direction and degree in listener perceptions of relative stress.

Ampicillin resistance in Hemophilus parainfluenzae.

Ampicillin resistance among strains of Hemophilus is usually due to production of beta-lactamase. This paper reports the isolation of a strain of H. parainfluenzae resistant to ampicillin with no detectable beta-lactamase or amidase activity. The organism, isolated from the blood of a patient who had aortic valve endocarditis, gave a zone diameter consistent with ampicillin sensitivity when tested by disc diffusion in Mueller-Hinton agar supplemented with 1% IsoVitaleX and 1% hemoglobin. Broth dilution testing in Levinthal medium, however, revealed the following minimal inhibitory cencentrations: ampicillin, 32 micrograms/ml; penicillin, 256 micrograms/ml; methicillin, 128 micrograms/ml; carbenicillin, 128 micrograms/ml; and cephalothin and chloramphenicol, 1.0 micrograms/ml. The results of acidimetric, iodometric, and chromogenic cephalosporin methods for detection of beta-lactamase were negative. Beta-lactamase activity could not be demonstrated in cell sonicates or induced by growth of the cells in antibiotic-containing medium. In addition, no extracellular degradation of either ampicillin or penicillin could be demonstrated.

Bioassay for determination of vancomycin in the presence of rifampin or aminoglycosides.

Vancomycin determinations were performed in the presence of an aminoglycoside or rifampin. A previously reported bioassay method was modified by using a rifampin-resistant strain and increasing the NaCl concentration in the minimal salts-glucose assay agar from 0.2 to 6.0%.