Differential visceral blood flow in the hyperdynamic circulation of patients with liver cirrhosis.

BACKGROUND: With advancing liver disease and the development of portal hypertension, there are major alterations in somatic and visceral blood flow. Using phase-contrast magnetic resonance angiography, we characterised alterations in blood flow within the hepatic, splanchnic and extra-splanchnic circulations of patients with established liver cirrhosis. AIM: To compare blood flow in splanchnic and extra-splanchnic circulations in patients with varying degrees of cirrhosis and healthy controls. METHODS: In a single-centre prospective study, 21 healthy volunteers and 19 patients with established liver disease (Child's stage B and C) underwent electrocardiogram-gated phase-contrast-enhanced 3T magnetic resonance angiography of the aorta, hepatic artery, portal vein, superior mesenteric artery, and the renal and common carotid arteries. RESULTS: In comparison to healthy volunteers, resting blood flow in the descending thoracic aorta was increased by 43% in patients with liver disease (4.31 ± 1.47 vs. 3.31 ± 0.80 L/min, P = 0.011). While portal vein flow was similar (0.83 ± 0.38 vs. 0.77 ± 0.35 L/min, P = 0.649), hepatic artery flow doubled (0.50 ± 0.46 vs. 0.25 ± 0.15 L/min, P = 0.021) and consequently total liver blood flow increased by 30% (1.33 ± 0.84 vs. 1.027 ± 0.5 L/min, P = 0.043). In patients with liver disease, superior mesenteric artery flow was threefold higher (0.65 ± 0.35 vs. 0.22 ± 0.13 L/min, P < 0.001), while total renal blood flow was reduced by 40% (0.37 ± 0.14 vs. 0.62 ± 0.22 L/min, P < 0.001) and total carotid blood flow unchanged (0.62 ± 0.20 vs. 0.65 ± 0.13 L/min, P = 0.315). CONCLUSIONS: Rather than a generalised systemic hyperdynamic circulation, liver disease is associated with dysregulated splanchnic vasodilatation and portosystemic shunting that, while inducing a high cardiac output, causes compensatory extra-splanchnic vasoconstriction - the 'splanchnic steal' phenomenon. These circulatory disturbances may underlie many of the manifestations of advanced liver disease.

One-stage versus two-stage bilateral unicompartmental knee replacement: a comparison of immediate post-operative complications.

We retrospectively studied the major complications occurring after one- and two-stage bilateral unicompartmental knee replacements (UKR). Between 1999 and 2008, 911 patients underwent 1150 UKRs through a minimally invasive approach in our unit. Of these, 159 patients (318 UKRs) had one-stage and 80 patients (160 UKRs) had two-stage bilateral UKRs. The bilateral UKR groups were comparable in age and American Society of Anaesthesiology grade, but more women were in the two-stage group (p = 0.019). Mechanical thromboprophylaxis was used in all cases. Major complications were recorded as death, pulmonary embolus, proximal deep-vein thrombosis and adverse cardiac events within 30 days of surgery. No statistical differences between the groups were found regarding the operating surgeon, the tourniquet time or minor complications except for distal deep-vein thrombosis. The anaesthetic times were longer for the two-stage group (p = 0.0001). Major complications were seen in 13 patients (8.2%) with one-stage operations but none were encountered in the two-stage group (p = 0.005). Distal deep-vein thrombosis was more frequent in the two-stage group (p = 0.036). Because of the significantly higher risk of major complications associated with one-stage bilateral UKR we advocate caution before undertaking such a procedure.

Positive cone biopsy specimen margins in women infected with the human immunodeficiency virus.

OBJECTIVES: The purpose of this study was to compare the positive margin rate associated with cervical conization among women who are seropositive for human immunodeficiency virus with that among women who are seronegative. STUDY DESIGN: This was a cross-sectional study of 245 women who underwent cervical conization for the following indications: biopsy-proven cervical intraepithelial neoplasia grade 2 or 3, abnormal endocervical curettage specimen, cytologic-histologic examination discrepancy, persistent cervical intraepithelial neoplasia grade 1, or abnormal cytologic characteristics with inadequate colposcopic examination. RESULTS: Twenty-two (47.8%) of 46 women who were seropositive for human immunodeficiency virus and 65 (32.7%) of 199 women who were seronegative had positive cone biopsy specimen margins. In a multivariable logistic regression the human immunodeficiency virus-seropositive women had a 2-fold increased risk of having a positive cone biopsy margin (odds ratio, 2.25; 95% confidence interval, 1.07-4.76). CONCLUSION: If the presence of positive cone biopsy specimen margins represents the potential for disease progression, then our findings of a positive margin rate of nearly 50% in a human immunodeficiency virus-positive population may argue against the kind of conservative management of colposcopic follow-up that has been proposed for immunocompetent women.

Bacterial vaginosis as a risk factor for upper genital tract infection.

OBJECTIVE: The objective of this study was to determine whether the clinical diagnosis of bacterial vaginosis is associated with objective evidence of acute upper genital tract infection. STUDY DESIGN: Women who either met the Centers for Disease Control and Prevention's minimal criteria for acute pelvic inflammatory disease or had other "nonclassic" signs of upper genital tract infection (i.e., atypical pelvic pain, abnormal uterine bleeding, or cervicitis) were evaluated with either an endometrial biopsy or a laparoscopy with endometrial and fimbrial biopsies for objective evidence of upper genital tract infection. Bacterial vaginosis was considered present if three of the four following criteria were found: (1) homogeneous gray-white vaginal discharge, (2) vaginal pH > 4.5, (3) positive "whiff" test result, and (4) the presence of > 20% of epithelial cells classified as clue cells. Patients were considered to have upper genital tract infection if they had histologic, microbiologic, or laparoscopic evidence of upper tract infection. RESULTS: One hundred sixteen women were evaluated between August 1993 and March 1997 with complete evaluations. Objective evidence of upper tract infection was present in 56% (14/25) of women with the clinical diagnosis of bacterial vaginosis compared with 30% of women (27/91) who did not meet the clinical criteria (p = 0.015). Using logistic regression to control for confounding variables, we found that the presence of bacterial vaginosis was associated with a threefold increased risk of upper genital tract infection (adjusted odds ratio = 3.0, 95% confidence interval 1.2 to 7.6). CONCLUSIONS: Bacterial vaginosis is associated with an increased risk of objective evidence of acute upper genital tract infection. Future prospective studies are needed to determine whether treatment of bacterial vaginosis can reduce the risk of ascending infection.

Endovaginal sonography for the diagnosis of upper genital tract infection.

OBJECTIVE: To determine the clinical utility of transvaginal sonography for the diagnosis of upper genital tract infection. METHODS: Fifty-five women who either met the Centers for Disease Control and Prevention's minimal criteria for acute pelvic inflammatory disease or were being seen for non-classic signs of upper genital tract infection were evaluated. During abdominal and endovaginal ultrasound testing, fluid in the cul-de-sac, discrete tubes with or without tubal fluid, multicystic ovaries, and adnexal masses were noted. Upper genital tract infection was confirmed by laparoscopic visualization or histologic or microbiologic evidence of salpingitis of endometritis. RESULTS: The specificity of identifying fallopian tubes with or without intraluminal fluid on ultrasound was 97% (35 of 36); the sensitivity, however, was only 32% (six of 19). Calculated using Bayes theorem and based on a prevalence rate of 50%, the positive predictive value of visualizing fallopian tubes was 91%. The sensitivities associated with the visualization of a multicystic ovary or tubo-ovarian abscess were 42% (eight of 19) and 32% (six of 19), with specificities of 86% (31 of 36) and 97%, (35 of 36), and positive predictive values of 75% and 91%, respectively. Cul-de-sac fluid was associated with low sensitivity (37%; seven of 19), low specificity (58%; 21 of 36), and the lowest positive predictive value (47%). CONCLUSION: Endovaginal sonography has limited clinical utility in the diagnosis of upper genital tract infection due to its low sensitivity.

Cytologic-histologic discrepancy in human immunodeficiency virus-positive women referred to a colposcopy clinic.

OBJECTIVE: To evaluate the rate of discrepancy between cytology and histology in a referral-based population of human immunodeficiency virus (HIV)-positive women compared to HIV-negative women and women whose HIV status was unknown. METHODS: From January 1, 1990 to December 31, 1993, approximately 830 women underwent evaluation at Women and Infants' Hospital colposcopy clinic. Women who had histologic diagnosis and recent cytologic evaluation during this interval (N = 678) were selected for study. Forty-one HIV-positive women were compared to 228 HIV-negative women and 409 women whose HIV status was unknown. RESULTS: Of the 41 HIV-positive women, seven (17%) were noted to have a discrepancy between cytologic and histologic findings. In HIV-negative and HIV-unknown women, 15% (34 of 228) and 22% (91 of 409) were discrepant, respectively. Using HIV-negative women as the reference group, the relative risk of cytologic-histologic discrepancy was 1.1 (95% confidence interval [CI] 0.51-2.41) for HIV-positive women and 1.5 (95% CI 1.04-2.14) for women whose HIV status was unknown. CONCLUSION: Human immunodeficiency virus-positive women referred for colposcopic evaluation have no more cytologic-histologic discrepancy than HIV-negative women or women whose HIV status is unknown.

High-temperature superconductors, the first ternary system.

A new system of high-temperature superconductors is reported. The compounds, Mo(6 - x)A(x)S(6) where A is Cu, Zn, Mg, Ag, Cd, Sn, or Pb, are rhombohedral with a approximately 6.5 angstroms and approximately 90 degrees . The transition temperatures range from approximately 2.5 degrees K for the Cd compound to approximately 13 degrees K for the Pb compound.

Superconductivity of Double Chalcogenides: Lix Ti1.1S2.

Lithium titanium sulfides, Li(x)Ti(1.1)S(2)(0.1 x

Instabilities of high temperature superconductors.

We have observed the transition temperature of both the cubic and tetragonal phases of several high-temperature beta-W superconductors. The instability of the cubic lattice appears to be characteristic of high-temperature superconductors.

Superconductivity: the transition temperature peak below four electrons per atom.

It is shown that the superconducting transition temperature for compounds in seven different structure types exhibits a peak at about 3.7 to 3.9 valence electrons per atom.

Magnetic ordering in the rare-Earth hexaborides.

Magnetic ordering in the rare-earth hexaborides has been studied by a variety of methods, and a clear correlation with the presence of conduction electrons has been found.