Dissecting the impact of protein versus energy host nutrition on the expression of immunity to gastrointestinal parasites during lactation.

Many mammals exhibit a periparturient relaxation of previously established immune responses (PPRI) to gastrointestinal nematodes culminating in increased worm burdens. It has been suggested that the extent of PPRI may have a nutritional basis as it is considerably augmented when protein supply is scarce. Subsequent studies have shown that increased dietary protein intake can ameliorate this phenomenon. However, this effect is often confounded with increased food intake and thus increased energy levels. Herein, we aimed to dissect the effects of protein and energy nutrition on the immune status and resistance to re-infection with gastrointestinal nematodes in the periparturient host. The lactating, Nippostrongylus brasiliensis re-infected rat was utilised as an established model for mammalian PPRI. Experimental animals were assigned to restricted feeding regimens designed to achieve four pre-determined levels of crude protein (CP) at one of two levels of metabolisable energy (ME) and parasitological and immunological measurements taken at either day 6 or day 9 post re-infection. We clearly show that increased supply of dietary CP, but not increased dietary ME, significantly reduced worm burdens. The increased magnitude of worm expulsion with increased dietary CP supply strongly correlated with mucosal mast cell accumulation in the small intestine. In addition, increased CP and not ME supply increased mucosal eosinophil numbers. Furthermore, increased CP led to higher levels of total IgG at high ME only and there were interactive effects of CP and ME on serum levels of IgG1 and IgG2a. Perhaps surprisingly, CP nutrition did not affect expression of either Th1 (IFN-γ) or Th2 (IL-4, IL-13) cytokines in the mesenteric lymph nodes. These data emphasise the role of immunonutrition, and particularly dietary protein, in combating infectious disease such as gastrointestinal parasitism.

Virulence attenuation and live vaccine potential of aroA, crp cdt cya, and plasmid-cured mutants of Salmonella enterica serovar Abortusovis in mice and sheep.

Three live vaccine candidates of Salmonella enterica subspecies I serotype Abortusovis (aroA, cya crp cdt, and plasmid-cured strains) have been developed, and their efficacies in inducing humoral antibodies and protecting against abortion after challenge with wild-type strain SS44 were evaluated in sheep. Following estrus synchronization, animals were immunized 3 weeks after fertilization and boosted once 3 weeks later. Following challenge with wild-type SS44, pregnancy failure of vaccinated ewes was reduced compared to that of nonimmunized controls. Attenuation of each vaccine was also assessed in challenge experiments with nonimmunized pregnant ewes and in BALB/c mice. All three vaccine candidates appear to be safe for use in sheep and provide a model for the development of live vaccine candidates against naturally occurring ovine salmonellosis.

Diversity of genome structure in Salmonella enterica serovar Typhi populations.

The genomes of most strains of Salmonella and Escherichia coli are highly conserved. In contrast, all 136 wild-type strains of Salmonella enterica serovar Typhi analyzed by partial digestion with I-CeuI (an endonuclease which cuts within the rrn operons) and pulsed-field gel electrophoresis and by PCR have rearrangements due to homologous recombination between the rrn operons leading to inversions and translocations. Recombination between rrn operons in culture is known to be equally frequent in S. enterica serovar Typhi and S. enterica serovar Typhimurium; thus, the recombinants in S. enterica serovar Typhi, but not those in S. enterica serovar Typhimurium, are able to survive in nature. However, even in S. enterica serovar Typhi the need for genome balance and the need for gene dosage impose limits on rearrangements. Of 100 strains of genome types 1 to 6, 72 were only 25.5 kb off genome balance (the relative lengths of the replichores during bidirectional replication from oriC to the termination of replication [Ter]), while 28 strains were less balanced (41 kb off balance), indicating that the survival of the best-balanced strains was greater. In addition, the need for appropriate gene dosage apparently selected against rearrangements which moved genes from their accustomed distance from oriC. Although rearrangements involving the seven rrn operons are very common in S. enterica serovar Typhi, other duplicated regions, such as the 25 IS200 elements, are very rarely involved in rearrangements. Large deletions and insertions in the genome are uncommon, except for deletions of Salmonella pathogenicity island 7 (usually 134 kb) from fragment I-CeuI-G and 40-kb insertions, possibly a prophage, in fragment I-CeuI-E. The phage types were determined, and the origins of the phage types appeared to be independent of the origins of the genome types.

Lattice-switch Monte Carlo method: application to soft potentials.

The lattice-switch Monte Carlo method, recently introduced and applied in the context of hard spheres, is extended to particles interacting through a soft potential. The method utilizes a transformation that switches between configurations of two different crystalline structures, allowing the phase space of both structures to be explored in a single simulation and the difference between their free energies to be determined directly. We apply the method to determine the fcc-hcp crystalline phase behavior of the classical Lennard-Jones solid.

Analysis of Cervico-vaginal (Papanicolaou) smears, in girls 18 years and under

The study was conducted retrospectively at the Queen Elizabeth Hospital and a private laboratory in Barbados to determine the types of epithelial abnormalities in cervico-vaginal Papanicolaou (Pap)-stained smears, and their clinical implications in Barbadian girls, 18 years and under, during the five-year period January 1995 to December 1999. Two hundred and sixty-five Pap smears from 236 patients were examined and the gynaecological history, initial and repeat Pap smear diagnoses, and histology reports of these patients were analyzed. Of the 236 first-visit smears, 94 (39.8 percent) were abnormal with 36 (15.3 percent) displaying cytological features of squamous intra-epithelial lesions (SIL), (33 low grade and 3 high grade). A diagnosis of atypical squamous cells of undetermined significance (ASCUS) was reported in the remaining 58 (24.5 percent) abnormal smears, of which 35 (60.3 percent) were suspected to be related to human papillomavirus (HPV) infection. Twenty-two (23.4 percent) of these 94 patients, who had abnormal smears of either ASCUS or low grade squamous intra-epithelial lesions (LSIL) were re-evaluated within six to twelve months of the initial abnormal Pap smear diagnosis. Eight of these 22 patients (36.4 percent) had histological diagnosis of LSIL inclusive of cervical intra-epithelial neoplasia grade 1 (CIN 1) and condylomata. High-risk HPV DNA types were detected in two of these eight patients (25 percent). The study confirms that sexually active teenage girls are at risk of developing SIL and high-risk HPV infection. Screening of sexually active teenage girls by Pap smears followed by other appropriate investigative procedures is recommended. (AU)

Critical-point finite-size scaling in the microcanonical ensemble.

We develop a scaling theory for the finite-size critical behavior of the microcanonical entropy (density of states) of a system with a critically divergent heat capacity. The link between the microcanonical entropy and the canonical energy distribution is exploited to establish the former, and corroborate its predicted scaling form, in the case of the 3d Ising universality class. We show that the scaling behavior emerges clearly when one accounts for the effects of the negative background constant contribution to the canonical critical specific heat. We show that this same constant plays a significant role in determining the observed differences between the canonical and microcanonical specific heats of systems of finite size, in the critical region.

An analysis of cervico-vaginal (Papanicolaou) smears in girls 18 years and under

During the two year period, January 1995 to December 1996 124 cervico-vaginal smears from 109 girls 18 years old and younger were examined. The gynaecological history, cytology reports, histological and cytological follow-up reports were analyzed to determine the demographics, common infections, epithelial abnormalities and follow-up management in this age group. The mean age was 17.4 with a range of 15-18 years. Twenty-five percent were gravid and 4.5 percent multigravida. The teen delivery/termination ratio was 0.73:1. The most common specific infection was yeast and, suspected infection, HPV .39 percent had normal smears, 14.7 percent inflammatory epithelial changes, 36 percent atypical squamous cells of undetermined significance (ASCUS), 8.3 percent low grade squamous intra-epithelial lesions (LGSIL) and 1.0 percent high grade intra-epithelial lesions (HGSIL). The ASCUS/SIL ratio was 3.9. Only 40 percent of patients with cytologic diagnosis of SIL and 28 percent with ASCUS had follow-up by repeat smear and/or colposcopy, endocervical curettage and guided cervicals biopsy. Five (45 percent) of the followed up patients had LGSIL inclusive of CIN 1 and condyloma. These results indicate that sexually active girls are risk of developing SIL and those with a diagnosis of ASCUS should be adequately followed up.(AU)

Cervical cytology quality control cytological and histological correlation at a private laboratory in Barbados - abstract

In this study, the cytological and histological diagnoses made during a six and a half-year period were compared with the aim of assessing the diagnostic accuracy of cervical cytology in a small private laboratory. There were 3486 cases biopsied, 40 (1.2 percent) cases with previous inadequate cervical smears, 195 (5.6 percent) cases with normal cytology and the remaining 3251 (93.2 percent) with abnormal cytological diagnoses. The overall concordance between the cytological and histological diagnoses was 63.9 percent. The greatest concordance was in cases with cytodiagnosis of CIN grade 3 (CIS) and invasive carcinoma combined 100/112 (89.3 percent), and the lowest with normal cytodiagnosis 75/195 (38.5 percent) cases. The significant histological diagnoses of the discordant cases were CIN 22.6 percent, condyloma 15.3 percent and carcinoma 1.1 percent. Fifty percent of the carcinomas diagnosed by cytology were of endometrial origin. Significant discordance occurred in cases with cytodiagnosis of HPV infection and CIN, in that 113 cases with cytodiagnosis of HPV infection/codyloma had histological diagnosis of CIN, and 156 cases with the cytodiagnosis of CIN had histological diagnosis of condyloma. The sensitivity rate for the diagnosis of HPV infection or condyloma by cytology was 632/1214 (52 percent). Most of the cases with inadequate smears had histodiagnosis of cervicitis with inflammatory atypia. This study has shown that the cytological evaluation of the severity of significant cervical abnormalities was a reliable guide for the clinician to the proper management of the patient (AU)

What is the significance of the class II Papanicolaou-stained cervical smear in Barbados? - abstract

At the Barbados Reference Laboratory (BRL), Papanicolaou-stained cervical smears are reported by a modified Papanicolaou system of Classes I to V, accompanied by a description of the significant findings. Concerns and criticisms of too many Class II reports, quality assurance rate and management of such patients were addressed in this study. From 1986 to 1989, of 27,327 smears screened at the BRL, 8,581 (31.4 percent) were given a Class II report and 984 (11.5 percent) of these patients were biopsied; 60.1 percent (591) of the biopsies showed evidence of cervicitis with and without inflammatory epithelial atypia, 24.2 percent (238) had no diagnostic abnormality, 15.2 percent (150) had evidence of cervical intraepithelial neoplasia (CIN) and 0.4 percent (4) had frank malignancy. There were 3 cases of endometrial adenocarcinoma and one of invasive squamous cell carcinoma. The false negative rate for CIN was 15 percent. On reviewing 74 (48 percent) of the smears with corresponding histologic diagnosis of CIN/carcinoma, 22 (29.7 percent), including the case of invasive carcinoma, were missed. All these smears had a marked acute inflammatory exudate making assessment difficult. In conclusion, this study showed that a Class II smear indicated a reasonable chance (75.7 percent) of an abnormality in the cervix, ranging from cervicitis (high risk) to invasive cancer (low risk), and that the quality assurance for cytologic diagnosis of CIN was low (AU)