Accumulation of human immunodeficiency virus-specific cytotoxic T lymphocytes away from the predominant site of virus replication during primary infection

Down-regulation of the initial burst of viremia during primary human immunodeficiency virus (HIV) infection is thought to be mediated predominantly by HIV-specific CD8+ cytotoxic T lymphocytes (CTL). This response is associated with major perturbations in the T cell receptor (TCR) repertoire. To investigate the failure of the cellular immune response to adequately control viral spread and replication and to prevent establishment of HIV infection, changes in the TCR repertoire and in the distribution of virus-specific CTL between blood and lymph node were analyzed in three patients with primary infection. By the combined use of clonotype-specific polymerase chain reaction and analysis of the frequency of in vivo activated HIV-specific CTL, it was shown that HIV-specific CTL clones preferentially accumulated in blood as opposed to lymph node. Accumulation of HIV-specific CTL in blood occurred prior to effective down-regulation of virus replication in both blood and lymph node. These findings should provide new insights into how HIV, and possibly other viruses, elude the immune response of the host during primary infection.     

Methane Transformation in Presence of Carbon Dioxide on Activated Carbon Supported Nickel–calcium Catalysts

The objective of the present work was to study the catalytic reformation of methane in presence of carbon dioxide on activated carbon-supported nickel and calcium catalysts. Results are very promising ones because they suggests that it is possible to transform methane on these catalysts by using mild reaction conditions.     

Local Order and Structure in Mn-Substituted Manganites Studied by EXAFS

We report extended X-ray absorption fine structure measurements at the Mn K edge on La_0.25Ca_0.75Mn_0.92Cr_0.08O₃ samples. Macroscopically, the Mn substitution induces a short-range charge-ordered state in spite of the long-range one present in the parent manganite La_0.25Ca_0.75MnO₃. We show how on a local scale the structural EXAFS parameters still confirm the presence, with only a slight reduction, of the features characteristic of the charge ordered un-substituted compounds.     

45S5 bioactive glass coatings by atmospheric plasma spraying obtained from feedstocks prepared by different routes

45S5 bioactive glass powders with the composition of 45 SiO₂, 6 P₂O₅, 24.5 CaO and 24.5 wt% Na₂O were melted and quenched in water to obtain a frit. The frit was milled using two different routes: dry milling followed by sieving to obtain glass particles and wet milling followed by spray drying to obtain a powder comprising porous agglomerates. All feedstocks showed adequate characteristics that make them suitable to be deposited by atmospheric plasma spraying. The powders and coatings were characterised by field-emission gun environmental scanning electron microscope and X-ray diffraction. The roughness and the contact angle of the coatings were also determined. The bioactivity of the powders and coatings was assessed by immersion in simulated body fluid. It was found that bioactive glass prepared from bioglass frit by dry milling exhibited similar bioactivity as that of a commercial bioactive glass. All coatings produced showed good adhesion to the substrate as well as suitable surface properties to ensure efficient contact with body fluid. Regardless of the characteristics of the feedstocks or plasma spray conditions used, all coatings were exclusively made up of an amorphous phase. On the other hand, micrographs revealed that the characteristics of the feedstock strongly impact on the final coating microstructure. The most homogeneous microstructure was obtained when the feedstock was prepared by fine dry grinding of the frit. For this coating, the formation of a bioactive layer was also proved by Fourier transform infrared spectroscopy and X-ray diffraction.     

Effect of cerebral ischaemia on the cerebrovascular and cardiovascular response to haemorrhage

Reports studying the combination of low blood pressure and cerebral ischaemia are few, and it remains to be determined how cerebral circulatory insufficiency modifies the cerebral perfusion and the central haemodynamic response to blood loss. We hypothesised that occlusion of arteries to the brain modifies the cerebrovascular and cardiovascular responses to blood loss. Continuous measurements of the cerebral microcirculation with laser Doppler microprobes in the cerebral cortex were performed in anaesthetised pigs during cerebral ischaemia and haemorrhagic hypotension. The response to rapid bleeding (25% of the blood volume) was recorded during normal conditions and during cerebral ischaemia induced by bilateral occlusion of the common carotid arteries. During normal conditions haemorrhage caused insignificant decreases in cerebral microcirculation. Haemorrhage during bilateral carotid artery occlusion, however, caused significantly greater changes in cerebral microcirculation and a greater posthaemorrhagic increase in cerebrovascular resistance shortly after the blood loss. Haemorrhage during bilateral carotid artery occlusion also caused greater reductions in cardiac output and arterial pressure than similar blood loss caused during normal conditions. This study showed a disproportionate decrease in cerebral blood flow with haemorrhage during bilateral carotid occlusion, caused by an immediate increase in cerebrovascular resistance. The results suggest that even a moderate blood loss in patients with impaired cerebral circulation could be dangerous, because normal compensatory mechanisms to haemorrhage are impaired.     

Transrectal ultrasonography to assess local extent of prostatic cancer before radical prostatectomy

BACKGROUND: The safety and efficacy of operations for gastrointestinal diseases in very elderly patients has been a matter of debate in recent years. STUDY DESIGN: One hundred seventy-seven instances of carcinoma of the colon and rectum in patients more than 80 years of age who wee surgically treated between 1961 and 1987 were reviewed. They were compared with 623 similar instances in patients younger than 80 years of age who were treated during the same time period. RESULTS: Octogenarians and nonagenarians significantly more often displayed obstruction or perforation, elevated preoperative carcinoembryonic antigen, right-sided lesions, and solitary hepatic metastases, when present. Patients more than 80 years of age received adjuvant chemotherapy or radiotherapy less often. Carcinoma recurrence in very elderly patients implied a very poor prognosis, with only a 4 percent salvage rate. The actuarial five year survival rate was 32 percent for the older patients and 48 percent in the younger group (p < 0.05). There was no significant difference in operative mortality between the two groups. CONCLUSIONS: In general, age alone should not alter treatment strategy in patients with carcinoma of the colon and rectum.     

Uretero-iliac fistula

OBJECTIVE: To describe a case of uretero-iliac fistula, an extremely rare condition that is not easily diagnosed. METHODS/RESULTS: Herein we describe a 76-year-old female who had undergone repeated pelvic surgery for adenocarcinoma of the sigmoid. She had a right ureteral fistula that had been managed conservatively by insertion of a ureteral catheter. Diagnosis was made by selective arteriography of the iliac arteries. The patient was submitted to surgery; primary closure of the arterial fistula and nephroureterectomy were performed. CONCLUSIONS: Uretero-iliac fistula should be suspected in patients with a history of repeated pelvic surgery and ureteral catheter placement that present with massive hematuria.     

Pacing impedance variability in tined steroid eluting leads

The aim of the study was to investigate pacing impedance (PI) behavior in ambulatory patients. Eighteen atrial and 18 ventricular tined steroid eluting leads with 1.2-mm2 and 5.6-mm2 electrodes were implanted in 20 patients. At 9-27 months after implantation PI was measured automatically by means of additional algorithms downloaded via telemetry links into implanted Thera pulse generators. PI was determined based on the voltage drop on the output capacitor during the 5 V-1 ms pacing impulse, at the programmable sampling rates from 1 second to 30 minutes. The study examined in particular: (1) PI trends and variations associated with different breathing patterns, body postures, provocative maneuvers, bike exercise, and during 24 hours; (2) impact of pacing rate and AV-delay on PI; (3) correlation between PI variability and pacing threshold, lead configuration, absolute PI value, age, gender, disease, and cardiac chamber. The most important findings were: (1) large PI variations of up to 450 omega were observed in properly functioning leads, (2) PI variability exhibited a weak negative correlation with pacing thresholds as if electrode positional stability was not a major factor underlying PI variations, (3) unipolar and bipolar PI variations were equivalent to each other (correlation factor = 0.93) implying that PI was mostly dependent on the circumstances around the lead tip.