Eradication of Helicobacter pylori affects symptoms in non-ulcer dyspepsia

The efficient production of polyprotonated oligonucleotides, studied at n < or = 19, occurs from water/propan-2-ol solutions over an ammonium acetate concentration range between 2.5 and 40 mm and a pH range from 5 to 11. Average charge-state levels observed were approximately half of those found in mass spectra of polyanionic oligonucleotides, reflecting differences in sites of ionization: heterocyclic bases for protonation and phosphodiester backbone for deprotonation. Collision-induced dissociation mass spectra show three principal reaction paths: (1) release of protonated bases, with abundances dictated largely by base proton affinity; (2) phosphodiester chain cleavage at C3'-O3' indicative of sequence in the 3'-->5' direction; and (3) chain cleavage concomitant with base loss giving furan-type ions indicative of sequence in the 5'-->3' direction, analogous to reactions of polyanionic oligonucleotides. Thymine residues undergo very little protonation, resulting in characteristic absence of phosphodiester cleavage on the 3' side of T sites, producing mass-ladder gaps representing dinucleotides.     

A study of hepatic mitochondrial respiration and microsomal cytochrome P450 content in mice infected with the liver fluke Fasciola hepatica

Previous studies of the effects of infection of Wistar rats with the common liver fluke, Fasciola hepatica, on liver bioenergetic and drug metabolism have demonstrated a loss of respiratory control in isolated mitochondria and reduced microsomal cytochrome P450 content, respectively, from 2 weeks post-infection throughout the acute phase of the infection. In the present study male Balb/c mice infected with F. hepatica showed a loss of respiratory control in isolated liver mitochondria only at 4 weeks post-infection. A similar time course was demonstrated for a reduction in hepatic microsomal cytochrome P450 content. Preparations from infected CBA mice showed similar changes to Balb/c mice but mitochondrial respiration in preparations from infected Swiss outbred mice was normal. A host difference between strains of mice and between mice and rats is therefore evident in the timing and extent of liver mitochondrial dysfunction and in the timing of the decrease in the cytochrome P450 content of hepatic microsomes. This difference between hosts may be related to the reported differences in cellular inflammatory responses to the migrating juvenile flukes in the livers of rats and mice.     

A cell switching WDM broadcast LAN with bandwidth guarantee andfair access

This paper presents the design of a cell-switching wavelength division multiplexing (WDM) local area network (LAN), which constitutes a key component of a next-generation internet (NGI) consortium project recently funded by DARPA. An important goal of the NGI project is to support bandwidth-on-demand services with quality-of-service (QOS) guarantee over WDM networks. As a first step toward this goal, we have developed several fast scheduling algorithms for flexible bandwidth reservations and fair sharing of unreserved bandwidth in a WDM broadcast network with fast-tunable transceivers. Unlike circuit-based bandwidth reservation schemes that impose a fixed schedule precomputed on setup, our scheme deals with bursty traffic by allocating network resources dynamically using very efficient algorithms. Our algorithms are based on a new concept of computing maximal weighted matchings, which is a generalization of maximal matchings on unweighted graphs. We prove that our algorithms can support total reserved bandwidth of up to 50% of the network capacity, and in that case constant delay bounds are also established. Simulations show that our algorithms can in practice support much higher reserved bandwidth-up to 90% of network capacity, and with much better delay bounds, even for burst traffic. In addition to the bandwidth guarantee, the unreserved bandwidth can be shared fairly among the users using our fair access algorithms with case to 100% network utilization in simulations     

Breast Cancer Screening among Employed American Women

From the 1990 National Health Interview Survey Health Promotion and Disease Prevention supplement, the authors estimated the 1990 baseline prevalence of breast cancer screening among employed U.S. women aged 50-70 years. Proportions of women screened for breast cancer were calculated by occupational category and demographic characteristics, and were compared with the Healthy People 2000 objective that 60% of women aged 50 and older have had mammography and a clinical breast examination within the preceding two years. The objective was exceeded for white-collar workers (61.8%) and workers with some college (64.1%), but was not met by any blue-collar/service workers (40.8%); or any workers with only a high school diploma (54.7%) or less than a high school diploma (38.5%). Identification of occupational categories and demographic subgroups among working women will be helpful to those planning breast cancer screening programs, in both the public and the private sectors.     

The detection of endocervical gland involvement by high grade squamous intraepithelial lesions in smears prepared from endocervical brush specimens

The cytologic features of squamous cell carcinoma in situ with endocervical gland involvement have been described in cervical smears. We evaluated the presence of two types of cellular fragments in 43 cervical smears of high grade squamous intraepithelial lesions (HGSIL) to assess their ability to predict glandular involvement by HGSIL in subsequent cone biopsies. An endocervical brush was used to obtain all endocervical specimens. Of 16 cases without glandular involvement, fragments were present in 13 smears. Of 27 cases with glandular involvement, fragments were absent in 11 smears. No statistical association was identified between the presence of abnormal cellular fragments on cervical smears of HGSIL and endocervical gland involvement on cone biopsies.     

Rapidly progressive herpetic retinal necrosis: a blinding disease characteristic of advanced AIDS

Eleven patients with rapidly progressive herpetic retinal necrosis (RPHRN) complicating AIDS were investigated retrospectively to study the disease spectrum, systemic involvement, and therapy. The mean CD4 cell count was 24/microL. There was a characteristic disease pattern with rapid progression, 82% bilaterality, relative resistance to intravenous antiviral therapy, and 70% retinal detachment. Varicella-zoster virus was the probable cause in 10 patients (detected by polymerase chain reaction in two eyes investigated), and herpes simplex virus was the probable cause in one. Cutaneous zoster occurred previously in 73% but was not concurrent. Seventy-three percent had central nervous system disease, possibly virus-related. RPHRN may be a local herpetic recrudescence in an immune-privileged site with transneural spread. Only four of 20 affected eyes retained useful vision. Poor ocular bioavailability, retinal ischemia, acquired drug resistance, and strain pathogenicity may underlie treatment failure. Acyclovir therapy appears relatively ineffective. Combined intravenous and intravitreal therapy with foscarnet and ganciclovir may be the best current management. Research advances are needed urgently.     

Frequency response of multi-phase segmented k-space phase-contrast

A theoretical analysis of the temporal frequency response of multi-phase segmented k-space phase-contrast was developed. This includes the effects of both segment duration and the number of cardiac phases that are reconstructed. An increase in the number of views per segment and the corresponding increase in segment duration results in an increased smoothing or low-pass filtering of the time-resolved flow waveform. Reconstruction of all intermediate cardiac phases makes the Nyquist sampling frequency independent of the number of views per segment. This analysis was verified experimentally using a multi-phase phase-contrast segmented k-space MR pulse sequence. This sequence reconstructs all intermediate cardiac phases and uses fractional segments at the end of the cardiac cycle if an entire segment does not fit. The use of fractional segments increases the portion of the cardiac cycle over which data are acquired.     

Diagnosis of Trichomonas vaginalis infection by PCR using vaginal swab samples

Trichomonas vaginalis infection is the most prevalent nonviral sexually transmitted disease (STD) in the world. A PCR test using vaginal swab samples for the detection of T. vaginalis was developed to add T. vaginalis infection to the growing list of STDs that can be detected by DNA amplification techniques. A primer set, BTUB 9/2, was designed to target a well-conserved region in the beta-tubulin genes of T. vaginalis. All strains (15 of 15) of T. vaginalis tested were successfully detected by PCR giving a single predicted product of 112 bp in gel electrophoresis. No such targeted product was amplified with DNA from Trichomonas tenax, Trichomonas gallinae, Chlamydia trachomatis, Neisseria gonorrhoeae, Giardia lamblia, Chilomastix sulcatus, Dientamoeba fragilis, and Entamoeba histolytica. An optimal analytical sensitivity of one T. vaginalis organism per PCR was achieved. Culture, performed with the Inpouch TV culture system, was examined daily with a light microscope to identify T. vaginalis. Twenty-three of 350 (6.6%) vaginal swab samples from women attending an army medical clinic were culture positive for T. vaginalis. Of these culture positive specimens, PCR detected 22 of 23 (96%) with primer set BTUB 9/2, and wet preparation detected only 12 of 23 (52%). Seventeen specimens were BTUB 9/2-PCR positive and culture negative. Ten of these discordant specimens were determined to be as true positive by PCR using primer sets TVA 5-1/6 and/or AP65 A/B, which target different regions in the T. vaginalis genome, and seven were determined to be false positive. The sensitivity of BTUB 9/2-PCR was 97% and the specificity was 98%. The sensitivities of culture and wet preparation were 70 and 36%, respectively. The diagnosis of T. vaginalis infection by PCR is a sensitive and specific method that could be incorporated into a joint strategy for the screening of multiple STDs by using molecular amplification methods.     

Conformational changes of the H+-ATPase from Escherichia coli upon nucleotide binding detected by single molecule fluorescence

BACKGROUND: An antiendomysium antibody test using human umbilical cord as antigen has recently been introduced. METHODS: We determined IgA- and IgG-class antihuman umbilical cord (HUC-ab), antireticulin (ARA), and antigliadin antibodies (AGA) in 92 untreated adult coeliac patients, in 95 non-coeliac subjects, and in 4 coeliac patients with selective IgA deficiency. Tissue antibodies were measured with an indirect immunofluorescence method and AGA with an enzyme-linked immunosorbent assay. RESULTS: Of adult coeliac patients 85% were positive for IgA-class HUC-ab, 78% were positive for ARA, and 80% for AGA; the specificity for HUC-ab and ARA was 100%, and for AGA 86%. Combination of HUC-ab, ARA, and high-titre AGA increased the sensitivity to 96% without loss of specificity. IgG-class HUC-ab was positive in 12% of coeliac patients, in all four coeliac patients with IgA deficiency, and in none of the controls. CONCLUSIONS: The HUC-ab test is highly specific but not 100% sensitive for detecting adult coeliac disease. A combination of the IgA-class HUC-ab, ARA, and high-titre AGA tests is recommended. In selective IgA deficiency the IgG-class HUC-ab test seems to work well.     

Unequal subfamily proportions among honey bee queen and worker brood

Queens from three colonies of feral honey bees, Apis mellifera were removed and placed in separate nucleus colonies. For each colony, eggs and larvae were taken from the nucleus and placed in the main hive on each of 3-4 consecutive weeks. Workers in the queenless parts selected young larvae to rear as queens. Queen pupae, together with the surrounding worker pupae, were removed from each colony and analysed at two to three microsatellite loci to determine their paternity. In all three colonies, the paternity of larvae chosen by the bees to rear as queens was not a random sample of the paternities in the worker brood, with certain subfamilies being over-represented in queens. These results support an important prediction of kin selection theory: when colonies are queenless, unequal relatedness within colonies could lead to the evolution of reproductive competition, that is some subfamilies achieving greater reproductive success than others. The mechanism by which such dominance is achieved could be through a system of kin recognition and nepotism, but we conclude that genetically based differential attractiveness of larvae for rearing as queens is more likely.Copyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour.