Haematocrit heterogeneity in blood flows past microfluidic models of oxygenating fibre bundles.

Blood oxygenators act as an extracorporeal artificial lung during certain types of cardiac surgery and intensive care therapies. Inside these devices, blood is forced to flow across an oxygenating bundle, encountering interstitial gaps comparable to those typical of the microvasculature. Despite the well-known effects of such length scales on haemorheology and red blood cell (RBC) behavior, these are generally overlooked in oxygenator modeling and design; it is persistently assumed that RBCs are homogeneously distributed throughout the oxygenating bundle, independently of their microstructure arrangement or main flow directions. The goal of this study is to provide preliminary experimental evidence of heterogeneous RBC distributions inside oxygenating fibre bundles. To this end, a number of microchannels were manufactured inspired by actual oxygenating devices, considering simplified versions of their microstructure. These comprise staggered arrays of micro pillars, which were perfused with RBC suspensions, with feed haematocrit (Ht) and velocities relevant for clinical use. The microchannels were imaged using a microscope and high-speed camera to accurately capture cell distribution. The imaged blood flows revealed the non-uniform nature of RBC distributions in the arrays, characterized by local Ht gradients particularly around the O2 sources inside the bundle. These heterogeneous distributions should be accounted for during oxygenator design, as RBC concentration plays a key role in O2 transport and, ultimately, overall device performance.

Modular implant design affects metal ion release following metal-on-metal hip arthroplasty: a retrospective study on 75 cases.

Metal-on-Metal (MoM) total hip arthroplasty (THA) has been associated to wear and metal-ions release, controversially related to a variety of clinical complications. Little is known about the relevant design-dependent parameters involved in this process. The present study investigated the correlation between metal ion release in blood and revision rate as a function of: (i) specific MoM implant modular design parameters, (i.e. acetabular cup and femoral head diameters, taper adapter material and size, femoral neck material and modularity and stem size); (ii) MoM bilaterality. Co and Cr ions concentration levels in blood of 75 patients were retrospectively-evaluated with a mean follow-up of 4.8 years (range: 1.8-6.3). Patients were divided in a unilateral and a bilateral group. Statistical analysis was performed to find any significant difference related to acetabular cup diameter, femoral head diameter, taper adapter material/size, neck material/size and stem size. The bilateral MoM group had 4-times higher metal ion levels in blood than the unilateral one (p=0.017 only Cr), related to a higher revision rate (30% vs 20%): differences were 10-times higher particularly with a 48 mm femoral head diameter (p=0.012) and a Ti-alloy neck (p=0.041). Within the monolateral group using a shorter taper adapter and a shorter neutrally-oriented neck demonstrated higher ion levels (p=0.038 only Cr and p=0.008 only Co, respectively). The aforementioned design-features and MoM bilaterality are important risk-factors for metal-ion release in modular MoM THA.

Ureteral and bladder lesions after ballistic, ultrasonic, electrohydraulic, or laser lithotripsy.

Four techniques of intracorporeal lithotripsy are now available: ballistic, ultrasonic, electrohydraulic, and laser. Their therapeutic efficacies have generally been evaluated and compared, but very few data have been available on their relative risks of iatrogenic trauma to the urothelial wall. We conducted a comparative analysis of this risk by testing the pig ureteral and bladder wall with the EMS Lithoclast, Olympus ultrasonic lithotripter, Walz Lithotron EL 23, and Versa Pulse Ho:YAG Coherent Laser. We measured the number of shockwaves or the energy required to perforate the ureter and bladder by delivering shocks perpendicular to the walls. Ureteral perforation was impossible with the 1.0-mm Lithoclast transducer and the 1.5-mm ultrasound transducer. Perforation was induced after 250 shocks with the 0.8-mm Lithoclast transducer, after 110 shocks with the 3F electrohydraulic electrode, and after 0.02 kJ with the laser. Bladder perforation was impossible with the 2.0-mm Lithoclast device and the 3.4-mm ultrasound transducer but was induced after 0.04 kJ had been delivered with the laser. We evaluated the iatrogenic risk under normal conditions of use by delivering the shocks tangentially to the ureteral wall and perpendicular to the bladder wall. We sacrificed animals on days 0, 1, and 6. The immediate histologic lesions induced by the Lithoclast and the ultrasound lithotripter were similar, consisting of a moderate reduction of the epithelial layers or intraepithelial detachments. Electrohydraulic shocks induced almost complete abrasion of the urothelium, and the laser induced extensive lesions of partial or complete necrosis of the urothelial wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Endourological treatment of lumbar and iliac ureteral stones. A comparative study of 49 cases.

The efficacy of the Lithoclast has been described extensively in the recent literature. However, to our knowledge, few articles have dealt with the safety of this technique. We present a retrospective study of 49 patients with stones of the lumbar and iliac ureter treated between 1989 and 1992 either by means of the Lithoclast (17 patients), by electrohydraulic shock waves (16 patients), or by trapping the stones in a wire stone basket (16 patients). The success rates were 88% for the Lithoclast and wire stone baskets and 62% for electorhydraulic shock waves. The mean dimensions of the stones were 10 mm for the Lithoclast and electrohydraulic shock wave groups, and 7 mm for the wire stone basket group. Complications consisted of 7 ureteral lesions (2 cases with the Lithoclast, 4 cases with electrohydraulic shock waves and 1 case with the wire stone basket) and 1 stripping of the lower ureter following stone extraction with a wire stone basket, which required open reimplantation. This study demonstrates the efficacy and safety of the Lithoclast for the treatment of large stones of the lumbar and iliac ureter.

Exploration and endoscopic treatment of unilateral primary haematuria: is non-specific diffuse pyelitis a real entity?

Chronic unilateral primary haematuria is rare and raises difficult problems of diagnosis and treatment as most of the knowledge in this field has been based on a very limited number of patients. This clinical entity needs critical reevaluation as recent progress in endourological investigations has revealed that lesions other than the classical submucosal haemangioma are just as frequently responsible for unilateral primary haematuria. These endoscopic lesions have generally been poorly defined up to now and our data based on a retrospective review of 8 patients emphasises the persistent gaps in our understanding of the pathophysiology of this disease. Among the lesions responsible for unilateral primary haematuria, diffuse petachiae of the renal pelvis and cavities represent the most frequent endoscopic lesion described in our experience (50% of cases). Histologically, these diffuse lesions correspond to non-specific pyelitis, consisting of simple oedema of the lamina propria. In addition to its diagnostic role, endoscopy can also be used to effectively treat the lesions responsible for unilateral primary haematuria, using either electrocoagulation or nitrate cautery, provided a retrograde approach can be completed by a percutaneous approach, with an overall success rate of 75% of cases with a mean follow-up of 16 months.

[Experience of a vaccination campaign using the Edmoston Zagreb strain (EZ 19) coinciding with reports about numerous cases of measles in the USL 23 region of Arezzo]. / Esperienza di una campagna di vaccinazione con ceppo Edmoston Zagreb (EZ 19) in contemporanea con la denuncia da parte della popolazione della U.S.L. 23 di Arezzo di numerosi casi di morbillo.

At the end of December 1990, a vaccination campaign with attenuated measles virus strain Edmoston Zagreb was started at USL 23, Arezzo. Subjects to be vaccinated as identified by assessment of individual susceptibility represented 45% of 9609 children aged between 13 month and 10 years. At the end of January 1991, with the vaccination campaign in full swing, two cases of measles were reported. Subsequently, the number of cases reported grew steadily with differences in number of cases and age of sick children between the various districts of USL 23. Variability of susceptibility to measles had in fact been observed between these districts associated with the different degree of compliance with the vaccination campaign. Therefore, by active motivation of the population, the vaccination campaign was stepped up, and after June 1991 no further cases of measles were recorded.

The Swiss Lithoclast: a new device for endoscopic stone disintegration.

Even in the presence of extracorporeal shock wave lithotripsy there is still the need for endourological treatment of stones in the urinary tract. Stone fragmentation usually is achieved with either ultrasonic, electrohydraulic or laser lithotripsy. We report our early experience with a new, simply constructed machine at a reasonable cost for endoscopic stone disintegration--the Swiss Lithoclast. The principle of this lithotriptor is based on pneumatic shock waves induced by the central compressed air system of a hospital or by a compressor. This device was used to treat 151 patients with stones in the kidney, ureter, bladder or a Kock pouch continent urinary diversion. Endoscopic fragmentation was successful in all patients. Independent of the composition, all stones were disintegrated within a short period, indicating that the device may well represent an attractive alternative to standard endoscopic lithotriptors.

[Urinary catheterization: transurethral or suprapubic approach?]. / Sondage urinaire: voie transurétrale ou suspubienne?

75 patients, needing a bladder drainage for nonurological indications and having sterile urines were studied after randomization into two groups. In the first group, drained with an urethral catheter, urinary infection took place in 12 (= 30%) patients, while it was detected in 4 (= 11%) drained with a suprapubic catheter. In this latter group, patients felt more comfortable, had less pain; the duration of urinary drainage and hospital stay was shorter.

[Anthropometric state of nutrition in students of various elementary and secondary schools in Ancona]. / Stato di nutrizione antropometrico degli studenti di alcune scuole elementari e medie di Ancona.

An anthropometric assessment was made of the nutritional state of children from Ancona elementary and middle schools. It was found that the girls had more body fat than the boys, though the latter, too, displayed values above those reported in U.S. and Italian studies. The view is expressed that this excess fat requires counteraction through nutritional education. Diet and physical exercise are known to be important in the prevention of degenerative diseases of a metabolic nature. Such prevention must be undertaken as soon as possible.