Solution properties and light scattering measurements of poly(2,5-pyrimidinediylterephthalamide)

A Series of chains of different molecular weight of the fully aromatic polyamide poly(2,5-pyrimidinediylterephthalamide)

1 IUPAC name: poly(2,5-pyrimidinediyliminoterephthaloylimino).

(PPYMT) in the solvents 96 wt.-% sulfuric acid and methanesulfonic acid have been characterized by means of static and dynamic light scattering, dilute solution viscosimetry and measurements of the critical polymer volume fraction for the onset of a nematic phase. The experimental results are in good agreement with a model of stiff worm-like chains for the solution conformation of PPYMT, and the persistence length is estimated to be ca. 150 Å (lower limit: 50–100 Å).     

Differences in the response of Sprague-Dawley and Lewis rats to bezafibrate: The hypolipidemic effect and the induction of peroxisomal enzymes

The effects of bezafibrate administered at 10 and 50 mg/kg/day for 7 days to male Sprague-Dawley (SD) and Lewis rats were investigated in order to determine the interrelation between the changes in serum and hepatic lipid contents and activities of selected peroxisomal, microsomal and mitochondrial enzymes in the two rat strains. In both strains, bezafibrate effectively reduced serum and hepatic lipids, increased the liver weight, induced a proliferation of peroxisomes, and selectively elevated the activities of carnitine acetyltransferase and of the enzymes of the peroxisomal -oxidation system. Moreover, immunoblotting revealed that the drug specifically enhanced the concentration of only those peroxisomal enzymes involved in fatty acid -oxidation. The data obtained demonstrate that although the responses initiated by bezafibrate are qualitatively similar in both strains, they differ in their magnitude in a dose-dependent manner, with the Lewis strain exhibiting a more pronounced response than the SD rats. These results show that dose-dependent strain differences as well as the generally known species differences should be taken into account in pharmacological and toxicological evaluations of fibrates in rodents. Furthermore, generalization and extrapolation from rodent studies should be treated with great caution.     

Endometrial volume change during spontaneous menstrual cycles: volumetry by transvaginal three-dimensional ultrasound

Objective: At present, only limited data are available on endometrial volume during the menstrual cycle. Most of these studies deal with animal models and use magnetic resonance imaging for volume measuring. The application of three-dimensional ultrasound in endometrial volume estimation is the subject of this study.Setting: Patients visiting the outpatient unit of the division of endocrinology and reproductive medicine of a university hospital.Patient(s): Twenty patients with a history of a normal menstrual cycle were selected.Intervention(s): Ultrasound examinations were performed during a single menstrual cycle in addition to routine laboratory tests.Main Outcome Measure(s): Uterus-endometrial volume ratio.Result(s): Data from 18 patients could be evaluated. In 81 examinations the endometrium volume could be determined. Mean endometrial volume measured by three-dimensional ultrasound was 1.23 cm'. Mean uterus volume was 48.93 cm3. The change of the uterus-endometrial volume ratio showed a good correlation with the day of menstrual cycle. Quadratic regression analysis of volume and cycle length was R² = 0.432.Conclusion(s): Three-dimensional ultrasound allows assessment of volume data of the female internal genitalia. In this study changes of the endometrial volume in menstrual cycles were measured. Additional studies are required to give information on the clinical impact of this new technique of endometrial volume estimation.     

Evaluating sex chromosome content of sorted human sperm samples with use of dual-color fluorescence in situ hybridization

OBJECTIVE: Although most methods for selecting the sex of offspring by sorting spermatozoa are ineffective at shifting the ratio of Y- to X-containing cells, some commercial sources continue to offer such services. Our objective was to evaluate commercially “sorted” samples with use of dual-color fluorescence in situ hybridization and to identify variations in assessment by comparing motile and total sperm populations, donors, observers, and fluorescence in situ hybridization probes.STUDY DESIGN: Cryopreserved sperm from seven anonymous donors were processed as for insemination. Sperm cells from each total sample or motile subfraction were prepared for fluorescence in situ hybridization by incubation with disulfide-reducing agents to expand sperm nuclei. Two sets of X and Y chromosome–specific, fluorophore-labeled deoxyribonucleic acid probes were used. At least 400 nuclei from each preparation were classified independently by three blinded observers. Hybridization efficiency, aneuploidy, and sex chromosome content were evaluated in subsets of five unsorted, five female-oriented, and five male-oriented samples. Total and motile subfractions were compared with eight samples. Fluorescence in situ hybridization probes were compared in five paired unsorted samples.RESULTS: No differences were detected between washed samples and paired motile subfractions. No differences in hybridization and aneuploidy were detected between groups of sorted samples. The Y/X ratio was significantly different between the sorted groups. However, male-oriented samples had a lower Y/X ratio than female-oriented samples did. Observer and probe choice accounted for small but significant variations that did not alter conclusions about the Y/X ratio for sorted samples.CONCLUSION: In a series of 10 sorted samples from one commercial source, dual-color fluorescence in situ hybridization demonstrated a small but significant shift in the sex chromosome ratios among samples. However, this shift was opposite to that expected by the orientation of the sorted samples. (Am J Obstet Gynecol 1997;176:1172-80.)     

Acoustical modulation of electrically evoked otoacoustic emission in intact gerbil cochlea

In order to study the interaction between mechanical-electrical and electrical-mechanical transductions of outer hair cells (OHCs) in vivo, we observed the acoustically induced changes in the electrically evoked otoacoustic emission (EEOAE). One pole of a bipolar electrode was placed in the round window niche and the other pole on the surface of the first cochlear turn in the gerbil. A microphone and a speaker were used to monitor the EEOAE and to deliver an acoustical tone, respectively. It was found that a high sound level acoustical tone enhanced the EEOAE fine structure at frequencies below the acoustical frequency, and suppressed the overall level of the EEOAE at frequencies above the acoustical frequency. In addition, the EEOAE at frequencies approximately one half octave lower than the acoustical frequencies were relatively more enhanced or showed relatively less suppression than at other frequencies. The amplitudes of these changes had a positive relationship with acoustical tone levels. Furosemide eliminated the acoustically caused EEOAE change indicating that the acoustically caused change in the EEOAE is a phenomenon of the normal cochlea. One possible mechanism for the results is that the electrically and acoustically evoked basilar membrane (BM) vibrations interact at the EEOAE generation site and change the local mechanical and electrical properties. The second possible mechanism is that the acoustical stimulus creates an impedance discontinuity at its characteristic frequency location leading to a change in the reflected electrically evoked traveling wave, which may enhance or suppress the EEOAE by the vector summation of two waves.     

Surgical Variables Affecting Speech in Treated Patients With Oral and Oropharyngeal Cancer

Postoperative speech function may be influenced by a number of treatment variables. The objective of this study was to examine the relationships among various treatment factors to determine the impact of these measures on speech function. Speech function was tested prospectively in 142 patients with surgically treated oral and oropharyngeal cancer 3 months after treatment. Each patient's speech was recorded during a 6- to 7-minute conversation and while performing a standard articulation test, producing speech outcome measures of percent correct consonant phonemes and percent conversational understandability. Correlational analyses were used to determine the relationships among the speech outcome measures and 14 treatment parameters. Speech function was mildly to moderately negatively correlated with most surgical resection variables, indicating that larger amounts of tissue resected were associated with worse speech function. Overall measures of conversational understandability and percent correct consonant phonemes were related to extent of oral tongue resection, floor of mouth resection, soft palate resection, and total volume of tissue resected. These relationships varied depending on the method of surgical closure. Method of surgical reconstruction had a profound impact on postoperative speech function 3 months after treatment and was an important factor in determining how oral tongue resection influenced articulation and intelligibility. The combination of closure type, percent oral tongue resected, and percent soft palate resected had the strongest relationship with overall speech function for patients with surgically treated oral and oropharyngeal cancer 3 months after treatment.     

Marked abnormal quadruple screen in a patient with severe preeclampsia at 20 weeks with a triploid fetus.

Severe preeclampsia rarely occurs prior to 20 weeks of gestation except in pregnancies with triploidy. The patient reported herein is a 29-year-old primigravida who developed severe preeclampsia at 20 weeks of gestation. Evaluation of the pregnancy demonstrated a markedly abnormal quadruple screen. Amniocentesis demonstrated a fetus with triploidy, despite a normal appearance.     

Enhancement of manumycin A-induced apoptosis by methoxyamine in myeloid leukemia cells.

Farnesyltransferase inhibitors (FTIs) are currently under investigation for leukemia treatment. We evaluated the FTI manumycin A (manumycin) in two myeloid leukemia cell lines (U937 and HL-60). Manumycin induced nitric oxide production and apoptosis of the leukemia cells. Nitric oxide or other reactive oxygen species may induce oxidative DNA damage, and the number of apurinic sites increased after manumycin treatment, which was reversed by concurrent treatment with N-acetyl-L-cysteine. Since repair of DNA damage is important to cell survival, we hypothesized that methoxyamine, an inhibitor of base-excision repair, would enhance the antineoplastic effect of manumycin. The combination of manumycin and methoxyamine resulted in enhanced apoptosis by six criteria increased annexin V binding, release of mitochondrial cytochrome c into the cytosol, activation of caspase-9, activation of caspase-3, specific cleavage of poly-adenosyl ribose polymerase, and increase in the sub-G1 cell cycle fraction. The drug combination enhanced inhibition on the soft agar clonogenic assay and on the formazan dye cell viability assay. The effects of manumycin or manumycin plus methoxyamine on apoptosis were blocked by N-acetyl-L-cysteine, and partially by nitric oxide synthase inhibitors or scavenger of peroxide. We conclude that methoxyamine enhances manumycin-induced apoptosis in myeloid leukemia cells.