Nanoscale electronic order in iron pnictides.

The charge distribution in RFeAsO1-xFx (R=La,Sm) iron pnictides is probed using As nuclear quadrupole resonance. Whereas undoped and optimally doped or overdoped compounds feature a single charge environment, two charge environments are detected in the underdoped region. Spin-lattice relaxation measurements show their coexistence at the nanoscale. Together with the quantitative variations of the spectra with doping, they point to a local electronic order in the iron layers, where low- and high-doping-like regions would coexist. Implications for the interplay of static magnetism and superconductivity are discussed.

Measuring the effect of risk factors on coronary atherosclerosis: coronary calcium score versus angiographic disease severity.

OBJECTIVES: This study sought to determine whether noninvasive quantification of coronary calcium is comparable to selective coronary angiography in measuring the effect of cardiovascular risk factors on coronary atherosclerosis. BACKGROUND: Electron beam computed tomography (EBCT) allows the delineation of anatomic coronary atherosclerotic disease and may be useful for noninvasively defining the role of established and new cardiovascular risk factors in selected patient groups. METHODS: A total of 211 consecutive patients, 26 to 79 years old, referred for evaluation of suspected or recently diagnosed coronary artery disease were examined. Selective coronary angiography was used to define five angiographic disease categories: normal coronary arteries, nonobstructive disease and one-, two- or three-vessel disease. EBCT was used to calculate coronary calcium scores, and cardiovascular risk, including lipid variables and fibrinogen levels, was assessed. RESULTS: Coronary calcium score and angiographic disease severity categories were largely predicted by identical risk factors (i.e., age, male gender, total/high density lipoprotein cholesterol ratio, fibrinogen) and, to a lesser degree, hypertension. Only smoking predicted angiographic disease severity but not calcium scores. The risk factors together explained a comparable proportion of the variability in angiographic disease categories and in calcium score quintiles (33% vs. 41%, p=0.16 by bootstrap analysis). An overall risk score composed of these risk factors separated angiographic disease categories and calcium score quintiles with a similar area under the receiver operating characteristic curve ([mean+/-SE] 0.81+/-0.03 vs. 0.83+/-0.03, p=NS). CONCLUSIONS: Quantification of coronary calcium is comparable to selective coronary angiography in measuring the effect of established cardiovascular risk factors on coronary atherosclerosis. Thus, EBCT may be useful for the noninvasive evaluation of the relations between conventional or developing cardiovascular risk factors and coronary atherosclerosis.

Transient or occult HIV infections may occur more frequently than progressive infections: changing the paradigm about HIV persistence.

Evidence of transient HIV infections was found in 8 subjects at high-risk for HIV infection among 47 longitudinally studied over 2-5 (average approximately 3.5) years, whereas only two subjects developed progressive infection. All of these subjects developed serum antibodies (Ab) to conformational epitopes of HIV gp41 (termed "early HIV Ab"), but the 8 transiently infected subjects lost this Ab within 4-18 months, and did not seroconvert to positivity in denatured antigen EIA or Western Blot (WB). However, the two progressively infected subjects eventually seroconverted in the EIA and WB tests within one to two months after the appearance of "early HIV Ab". HIV env and nef sequences were directly PCR amplified from the peripheral blood mononuclear cells (PBMCs) of two of the eight transiently infected subjects during the time of "early HIV Ab"-postivity, and these showed significant sequence divergence from the HIV strains in the laboratory, indicating that they were not laboratory contaminants. Genome identity typing ("paternity-typing") of PBMC samples obtained at the time of "early HIV Ab"-positivity, and later when Ab was absent from each of the 8 subjects, showed that blood samples were not mixed-up. This provides further evidence that transient or occult infection with HIV does occur, and perhaps at a greater frequency than do progressive infections.

Comparative studies of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine.

OBJECTIVES: To compare the efficacy and safety of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine. DESIGN: Two multicenter, open-label, randomized 24-week studies. METHODS: Adults HIV-1 infection, HIV-1 RNA greater than 10000 copies/ml, and no prior lamivudine or protease inhibitor therapy were eligible. In a pilot study (Study A), patients received indinavir at 800 mg every 8 h, 1000 mg every 12 h, or 1200 mg every 12 h. In a subsequent study (Study B), patients received indinavir at 800 mg every 8 h or 1200 mg every 12 h. All subjects received zidovudine (300 mg) and lamivudine (150 mg) every 12 h. An intent-to-treat analysis was used. RESULTS: In Study A, which enrolled 88 patients, neither HIV-1 RNA nor CD4 cell responses differed significantly between treatment groups at 24 weeks when corrected for multiple comparisons. Study B enrolled 433 patients, but was prematurely discontinued when interim analysis suggested greater efficacy of three-times-daily indinavir. Of the first 87 patients reaching week 24, HIV-1 RNA was less than 400 copies/ml in 91% receiving three-times-daily versus 64% receiving two-times-daily indinavir (P < 0.01). CONCLUSION: Three-times-daily indinavir appears more efficacious than two-times-daily dosing when administered with zidovudine and lamivudine. Two-times-daily indinavir dosing should only be considered in situations characterized by favorable pharmacokinetic drug-drug interactions.

Propranolol stereoisomer plasma concentrations and portal haemodynamic response in patients with liver cirrhosis.

BACKGROUND: The haemodynamic effect of propranolol on portal pressure in patients with portal hypertension is highly variable and does not correlate with propranolol racemate plasma concentrations. AIM: To investigate the stereoselective metabolism of the propranolol enantiomers and its impact on portal haemodynamics in patients with liver cirrhosis since only S-propranolol is haemodynamically active. METHODS: Twenty patients with liver cirrhosis and portal hypertension received 40 mg propranolol orally. Portal blood velocity (PBV) and propranolol stereoisomer plasma concentrations were determined. RESULTS: During the 4 h examination period we observed a significant reduction in PBV (18.3 +/- 2.2%, P < 0.0001) vs. baseline. The area under the curve (AUC) during the study period was significantly different for the two isomers (S-propranolol 1217.0 +/- 118.5 nmol.h/L; R-propranolol 728.8 +/- 103.8 nmol.h/L, P < 0.0001). Seven patients (35%) were portal haemodynamic non-responders to propranolol. Propranolol stereoisomer AUC values were no different between responders (S-propranolol 1133. 3 +/- 132.0 nmol.h/L; R-propranolol 718.0 +/- 129.7 nmol.h/L) and non-responders (S-propranolol 1371.8 +/- 250.5 nmol.h/L; R-propranolol 746.9 +/- 200.3 nmol.h/L); neither was there a correlation between propranolol enantiomer plasma concentrations and the portal haemodynamic effect. CONCLUSIONS: Our data demonstrate a stereoselective metabolism of propranolol enantiomers in liver cirrhosis. However, following oral propranolol administration, stereoisomer plasma concentrations do not predict the portal haemodynamic effect.

Risk factors for colonization or infection due to methicillin-resistant Staphylococcus aureus in HIV-positive patients: a retrospective case-control study.

OBJECTIVE: To determine the risk factors for colonization or infection with methicillin-resistant Staphylococcus aureus in human immunodeficiency virus (HIV)-infected patients. DESIGN: Retrospective matched-pair case-control study. SETTING: Continuity clinic and inpatient HIV service of a university medical center. POPULATION: Patients with HIV infection from the general population of eastern and coastal Texas and from the Texas Department of Criminal Justice. DATA COLLECTION: Patient charts and the AIDS Care and Clinical Research Program Database were reviewed for the following: age, race, number of admissions, total hospital days, presence of a central venous catheter, serum albumin, total white blood cell count and absolute neutrophil count, invasive or surgical procedures, any cultures positive for S. aureus, and a history of opportunistic illnesses, diabetes, or dermatologic diagnoses. Data also were collected on the administration of antibiotics, antiretroviral therapy, steroids, cancer chemotherapy, and subcutaneous medications. RESULTS: In the univariate analysis, the presence of a central venous catheter, an underlying dermatologic disease, lower serum albumin, prior steroid therapy, and prior antibiotic therapy, particularly antistaphylococcal therapy or multiple courses of antibiotics, were associated with increased risk for colonization or infection with methicillin-resistant S. aureus. Multivariate analysis yielded a model that included presence of a central venous catheter, underlying dermatologic disease, broad-spectrum antibiotic exposure, and number of hospital days as independent risk factors for colonization or infection with methicillin-resistant S. aureus. CONCLUSIONS: In our HIV-infected patient population, prior hospitalization, exposure to broad-spectrum antibiotics, presence of a central venous catheter, and dermatologic disease were risk factors for acquisition of methicillin-resistant S. aureus.

Hemostatic changes due to the venom gland extract of the red-necked keelback snake (Rhabdophis subminiatus).

After a bite by the aglyphous red-necked keelback snake Rhabdophis subminiatus a complete defibrinogenation syndrome with severe hemorrhagic diathesis developed in a 25-year-old man. In vitro studies showed that the venom gland extract of the snake contains a very active prothrombin (Factor II) activator. The thrombin generated is inhibited neither by antithrombin III nor the antithrombin-III-heparin complex. The venom gland extract stimulated also the tissue plasminogen activator; however, it did not cause direct activation of plasminogen, protein C, Factor X or direct degradation of fibrinogen.

Intraperitoneal fibrin-formation and its inhibition in CAPD.

The intraperitoneal fibrin formation and its inhibition by intraperitoneal heparin (5000 U) was investigated in six patients on CAPD. The intraperitoneal heparin concentration decreased linearily from 1.78 U/ml to 1.13 U/ml during a 4-hour dwell time. The antithrombin III-concentration increased to 0.56 +/- 0.1 mg/dl, reaching 1.87% of normal plasma values. The antithrombin III-portion of total protein was 0.62% in plasma and 0.79% in dialysate. The fibrinopeptide A-concentration, a specific product of thrombin action on fibrinogen was 37.1 +/- 11.8 ng/ml in plasma (normal range: less than 2.5 ng/ml) and 153.4 +/- 16.8 ng/ml in dialysate during regular CAPD. After the addition of 5000 U heparin the fibrinopeptide A-concentration in dialysate decreased to 11.6 +/- 2.6 ng/ml during a 4-hour dwell time. In vitro experiments showed no remarkable inhibition of fibrin formation by heparin without antithrombin III in dialysate. We suggest that the fibrinopeptide A is produced intraperitoneally and the antithrombin III-concentration in dialysate is sufficient to inhibit the fibrin formation after acceleration by heparin.

Effect of hemodialysis and antiretroviral therapy on plasma viral load in HIV-1 infected hemodialysis patients.

BACKGROUND: Plasma viral load has become an important test in predicting the progress of HIV-1 infected patients. The higher the viral load the faster is the progression to AIDS. As HIV-1 infected hemodialysis (HD) patients have higher mortality and morbidity than HIV-1 infected non-dialysis patients, and as all the blood tests in the HD patients are drawn during HD, we measured the effect of HD and antiretroviral therapy on viral load in HIV-1 infected HD patients. PATIENTS AND METHODS: We measured plasma viral load pre-dialysis and post-dialysis in 10 HIV-1 infected HD patients. The viral load was measured using an in vitro quantitative nucleic acid amplification test. We also compared viral load in 8 HIV-1 infected HD patients on one antiretroviral drug with 8 HIV-1 patients on two (6) or three (2) antiretroviral drugs. RESULTS: There was a small reduction in plasma viral load postdialysis in all HIV-1 infected HD patients (45% +/- 5.4, 0.3 log +/- 0.05, p < 0.0004). However, HIV-1 RNA could not be detected in the ultrafiltrate. The patients who were on two or three antiretroviral drugs had lower viral load (8915 +/- 3702 vs. 351440 +/- 101237, p < 0.004) and higher CD4 count (355 +/- 81 vs 82 +/- 39, p < 0.009) than patients on only one antiretroviral drug. CONCLUSION: We conclude that there is a small reduction in plasma viral load in HIV-1 infected hemodialysis patients post-dialysis. As no viral RNA could be detected in the ultrafiltrate, the reduction could be due to nonspecific adsorption of the viral RNA to the dialysis membrane. HIV-1 infected hemodialysis patients who are on two or three antiretroviral drugs had significantly lower viral load and higher CD4 count than patients on only single antiretroviral drug. Therefore a single antiretroviral drug should not be used in treating HIV-1 infected HD patients.

[Ultrasound controlled puncture of renal cysts: biochemical and radiological findings (author's transl)]. / Ultraschallgeführte Nierenzystenpunktion. Biochemische und röntgenologische Befunde.

Ultrasonographically-guided renal cyst puncture was done in 128 patients on outpatient basis. Cortical renal cysts were seen in both male and female patients in an equal ratio. Mean age was 59.6 years. Complication rate of percutaneous puncture was low. Only twice transient haematuria was observed, needing no treatment. Aspirated fluids were examined cytologically and biochemically. None of the aspirated specimens showed malignant cells. Biochemically lactate dehydrogenase activity and concentrations of total protein, cholesterol, triglycerides, potassium and creatinine were determined. Potassium and creatinine determination were found to be valuable in distinguishing between cystic-like lesions containing secondary urine (like caliceal cysts, hydronephrosis, urinoma) and those containing primary urine (like cortical renal cysts). Thus measurement of potassium and creatinine in aspirated fluids may be helpful in determining the need for open exploratory surgery. In cases where cystic lesions produce urographically visible defects of the pelvic system, a dilatation of this area after evacuation of the cyst can be demonstrated via intravenous urography.

Immunotherapy of CMV infections.

Immunotherapy has not only become the accepted standard for some CMV infections, but also remains an area of active investigation for the treatment and prophylaxis of CMV infections. Polyclonal immunoglobulin administration has improved the survival of CMV pneumonitis in BMT recipients, and monoclonal anti-CMV antibodies, notably MSL-109, appear to increase the time to relapse of CMV retinitis in patients with AIDS. The adoptive transfer of CMV-specific CD8 cells is under investigation as another CMV prophylactic strategy in BMT recipients, and it is hopeful that this methodology can be applied to the therapy of established CMV infections.

TORCH infections. Diagnosis in the molecular age.

TORCH agents cause a varied spectrum of disease. Advances in ultrasound, invasive perinatal procedures and molecular diagnostics have allowed in utero evaluation. Infected fetuses, especially those which are sonographically abnormal, may be treated in utero depending upon the pathogen and attendant pathophysiology. Subclinical perinatal infections may lead to later childhood deficits. Such infected fetuses may benefit from early diagnosis and prompt initiation of rehabilitative measures.