[Effects of ionization of the air on some bacterial strains]

For some time a bactericidal activity is recognized by air ionization. Recently it has been demonstrated that while the bactericidal effect of the positive ions is due to physical factors, the negative ions operate either by physical or chemical effects. This depends on the presence of oxygen: negative air ionization consists mainly of oxygen ions with a strong oxidizing effect. Beneficial effects of negative air ionization on human health have been recently demonstrated in several studies. In this research the bactericidal effect of the negative air ionization on some strains of Gram+ and Gram- bacteria has been estimated. Trials with Escherichia coli ATCC and Staphylococcus aureus ATCC strains have been carried out using a point-acting tester as generator of negative oxygen ions. The ion concentration was estimated in 8-10(6) ion/cm3 air at a distance from the source of 0.5 metric. The tests were performed in a special room of the microbiology laboratory, equipped without metal furniture and in absence of people. Suspensions of bacterial cells were spread on a solid medium in Petri dishes and then placed, without cover, under the ion generator, at different distances from the source, for 24 hours. The results show a greater effect of the negative air ions on the Gram- than on the Gram+ cells; the number of colonies of Escherichia coli grown under ionization was estimated to be 15.1 times less than of the colonies grown without ionization, while the growth of Staphylococcus aureus in the same conditions was only 4.5. time less. No contamination of Petri dishes by environmental bacteria has ever been occurred during trials: this could demonstrate a biocidal effect of the negative ionization also on air bacteria.

Percutaneous fibercholangioscopies

This is a report on our experience in 309 percutaneous fiberendoscopies of the biliary tract done in 106 patients of the 115 scheduled for the procedure. We describe the relevant approaches, techniques, complications and results. In particular, percutaneous transhepatic cholangioscopies (PTCS) were accomplished on transhepatic percutaneous drainages located radiologically in 35 patients: in 13 for differential diagnosis to distinguish between malignant and benign stenoses (diagnostic accuracy in 92% of the biopsies), in 22 cases with therapeutic intent, including 14 lithotomies for extrahepatic biliary tract calculosis, combined in 4 cases with a simple dilatation of the papilla and a percutaneous "descending" papillotomy; in 7 patients a dilatation of the biliary tract (BT) or of the stenosis of a biliodigestive anastomosis was accomplished (malignant in 4 patients, benign in 3 patients). In 38 patients postoperative percutaneous transhepatic cholangioscopies were performed along surgically located transparietohepatic drains, both to assess the biliodigestive anastomosis healing process carried out by two different techniques (30 patients), and to complete the biliary tract drainage as part of the primary and secondary endoscopic surgical treatment of massive intrahepatic lithiasis. In two further patients affected by such pathology, PTCS was done in combination with fibercholangioscopy performed via a transjejunal approach using a Völker drain on a Y-shaped loop. Nine of these patients were treated successfully and one patient later underwent a left hepatectomy, since attempts to drain that area had remained unsuccessful. The transjejunal approach was carried out in 3 patients as a diagnostic measure: in two cases to check the lithotomy, and in one case to check a cholangiojejunal anastomosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous foveal and parafoveal electroretinograms in hereditary degeneration of the central retina

Simultaneous foveal and parafoveal electroretinograms (ERG) in response to two identical checks (6 degrees per side) alternating at constant mean luminance were recorded in 26 patients (52 eyes) affected by central hereditary chorioretinal diseases and in 14 age-matched normal subjects (14 eyes). Patients were divided into four groups according to clinical diagnoses: 1. Stargardt's disease; 2. cone dystrophy; 3. vitelliform degeneration; 4. pattern dystrophy. The amplitude and latency of the foveal ERG and the amplitude ratio between foveal and parafoveal ERG (F:PF ratio) were measured. The mean foveal ERG amplitude was significantly lower than the control mean in all patient groups. The foveal ERG latency showed a trend to a increase in all pathological groups. However, this difference was not statistically significant. The mean value of F:PF ratio was significantly reduced as compared with the control mean in Stargardt's disease and cone dystrophy only. In 46 of 52 affected eyes (88.5%) at least one of the electrophysiological parameters was abnormal. Our results suggest that the simultaneous foveal and parafoveal ERG recording may be a sensitive technique in hereditary degenerations of the central retina. This method may also contribute to a better understanding of cone degeneration pathophysiology.

Macular electroretinogram as a function of age of subjects

Macular and paramacular electroretinograms in response to two adjacent checks (6 deg/side), alternating at constant mean luminance, were recorded in 34 normal subjects ranging in age from 16 to 74 years. The macular electroretinogram declines progressively in amplitude with age (R = -0.42; P = 0.013). The amplitude ratio between macular and paramacular responses tends to be independent of age (R = -0.21; P = 0.22). Age-related changes in the macular electroretinogram shown in our study are consistent with previous anatomical and functional studies, which indicate a deterioration of photoreceptors beyond 20 years of age. These results suggest a possible use of this technique for future studies on macular degeneration.

Technique and endoscopic monitoring of the healing process in bilioenteric anastomoses

Thirty-three patients were given cholangiojejunoanastomoses: 13 for benign postoperative stenoses of the biliary tract (BT) with or without lithiasis; five for massive intra and extra-hepatic lithiasis; 15 for malignant stenoses on the upper third of the biliary ways. The 15 patients in Group A were given a muco-mucosal anastomosis and the 18 in Group B extramucosal anastomosis after excision of the excess mucosa on the jejunotomy. In both groups an interrupted suture using fine, slow-absorption thread was employed. Three patients (two from Group A and one from Group B) were excluded from the study due to postoperative filtration of the anastomosis. Transhepatic cholangioscopic monitoring of the healing process on the 15th, 20th, 30th and 40th day showed that while both types of anastomosis were equally secure, the extramucosal suture after excision of excess mucosa produced wider anastomoses and is therefore advisable in all cases of bilioenteric anastomosis (BEA) but especially when the biliary ways are narrow or tendentially thin-walled.

Pattern electroretinogram as a function of spatial frequency in ocular hypertension and early glaucoma

Pattern electroretinograms (PERGs) in response to 8.3 Hz alternating gratings (16.6 rev/sec) of different spatial frequencies were recorded in normal subjects as well as in patients affected by early glaucoma and ocular hypertension. In normal subjects the PERG response is spatially tuned, with a maximum at about 1.5 cycles/deg and attenuation at higher and lower spatial frequencies. In all cases of early glaucoma and in the great majority of cases of ocular hypertension the PERG was reduced, as compared with that of normal subjects, mainly in the medium range of spatial frequencies (at which the PERG has its maximal amplitude).

Simultaneous macular and paramacular ERGs recorded by standard techniques

A technique for the simultaneous recording of two small-field electroretinograms (ERGs), macular and paramacular, employing standard apparatuses for stimulation and analysis is described. The stimuli consisted of two adjacent checks (6 deg/side) obtained by masking the display of a commercially available TV pattern stimulator. The checks were square-wave-modulated in counterphase at 3.12 Hz. The subjects fixated the center of one of two checks. In one stimulus cycle, two ERGs could be distinguished: one from the macular area and the other from the adjacent area. The macular ERG is about twice as large as the paramacular. ERGs recorded by this technique can be considered focal since (i) they show a sharp fall-off in amplitude when the stimulus is displaced from the fovea, and (ii) they are no longer recordable when the stimulus is centered on the optic disk or on a large macular scar.