Biomedical subjects

I Tsiaoussis

Publications and source records attributed to I Tsiaoussis.

4 recordsLinked to original sources

PubMed2006

Well-orientated cubic boron nitride nanocrystals as studied by high-resolution transmission electron microscopy.

In a boron nitride thin film, grown on a Si (100) substrate by radio frequency magnetron sputtering, a striking nanostructure is observed by high-resolution transmission electron microscopy. It consists of cubic boron nitride nanocrystals with a rather good triangular shape, pointing always to the substrate. The nanocrystals are usually highly defected and present their own interesting internal structure. Texture formation is observed within a nanocrystal, with all the subgrains observed to have a common <011> axis, which is also approximately parallel to a <011> axis of the Si substrate, i.e. the nanocrystals are very well structurally orientated in relation to the Si substrate (self-organized). Dislocations and stacking faults are also found in the nanocrystals.

Journal Article↗

PubMed2006

Structural models for twin interfaces in Pd thin films.

In a Pd thin film grown on a 6H-SiC (0001) substrate, several twin interfaces have been observed, classified as (1) {111}Sigma = 3 twin interfaces and (2) {221}Sigma = 3 twin interfaces. The first ones are coherent twin interfaces and in some cases exhibit steps of one or more atomic layers in height. The second ones are perpendicular to the first ones. They usually appear with a rigid-body displacement, but in some cases no displacement was observed. Models for the interfaces are proposed.

Journal Article↗

PubMed1999

Impairment of anorectal function in diabetes mellitus parallels duration of disease.

PURPOSE: The aim of this study was to investigate any possible relation between the severity of anorectal dysfunction in diabetes mellitus and duration of disease and presence of microangiopathy or neuropathy or both. METHODS: Standard multiport anorectal manometry was performed in 25 healthy control subjects (10 males; age (mean +/- 1 standard deviation), 62 +/- 14 years) and 38 patients with diabetes mellitus. Patients were divided into two groups according to the duration of the disease: Group A (19 patients) with a duration less than 10 years (7.2 +/- 2.5; 8 males; age, 57 +/- 18) and Group B (19 patients) with a duration longer than 10 years (19.8 +/- 5.6; 6 males; age, 62 +/- 15). RESULTS: Results are reported as mean +/- one standard deviation. Patients showed lower resting and squeeze anal pressures (P < 0.01), impaired rectoanal inhibitory and anocutaneous reflexes, and reduced sensitivity in rectal distention (P = 0.004) as compared with controls. In addition, Group B showed a significantly increased incidence of microangiopathy (P = 0.04) and autonomic and peripheral neuropathy (P = 0.002), significantly reduced basal and squeeze anal pressures (52 +/- 16 vs. 64 +/- 24 mmHg; P = 0.03 and 98 +/- 39 vs. 124 +/- 54 mmHg; P = 0.04, respectively), reduced amplitude of slow waves (7.3 +/- 3 ts. 9.5 +/- 3.7 mmHg; P = 0.03), anal leak in smaller rectal volumes (P = 0.003), and reduced response of the anal sphincter at the anocutaneous reflexes (29 +/- 14 vs. 39 +/- 14 mmHg; P = 0.05) compared with Group A. The former group of patients exhibited a significantly higher incidence of fecal incontinence (P = 0.008). CONCLUSION: Patients with long-standing diabetes mellitus have increased incidence of fecal incontinence and severely impaired function of both the anal sphincters and the rectum. These findings could be attributed to the increased incidence of microangiopathy and autonomic and peripheral neuropathy observed in this subset of diabetic patients.

Anal Canal↗

PubMed1998

Gallbladder fasting volume is reduced and gallbladder postprandial emptying is enhanced by intravenous erythromycin.

It has been recently shown that erythromycin, a macrolide antibiotic, exhibits prokinetic properties, by enhancing gastric emptying in health and disease and by inducing gallbladder contraction. The aim of the study was to further investigate the effect of intravenous erythromycin on gallbladder motility during fasting and postprandial states. In 10 healthy male subjects gallbladder emptying was assessed by ultrasonography on three different occasions, each in a random sequence, as follows: (1) after giving 300 ml of fresh milk and infusing normal saline as placebo (postprandial emptying), (2) after infusing 200 mg of erythromycin during the fasting state, and (3) after infusing 200 mg of erythromycin along with ingestion of 300 ml of fresh milk. Infusion of erythromycin and placebo lasted 10 min. From the emptying curves, the duration of the lag phase of emptying, the ejection fraction of emptying, and the time by which maximal emptying was achieved were calculated. Infusion of erythromycin induced an immediate contraction [lag phase (+/-SD): 1.3+/-2.6 SD min] of the gallbladder by 42.1+/-22% of its initial volume. Infusion of erythromycin during the postprandial state significantly decreased the duration of the lag phase (1.3+/-3.5 min after erythromycin plus test meal versus 3.6+/-4.2 min after test meal only, P < 0.04) and significantly increased the ejection fraction (78+/-8.5% after erythromycin plus test meal versus 60.6+/-8.5% after test meal only, P < 0.0008). It is concluded that intravenously given erythromycin induces contraction of the gallbladder during the fasting state and enhances postprandial gallbladder emptying by accelerating the initiation and increasing the extent of emptying.

Adult↗