Thyroidectomy: is it safe to be performed by general surgery residents? - single centre experience.

BACKGROUND: Thyroidectomy carries a risk of two crucial complications - recurrent nerve palsy and hypocalcaemia. The aim of the study was to assess the safety of thyroidectomy performed by general surgery residents. METHODS: Data of 515 patients, who underwent total thyroidectomy between the years 2015 and 2019, were prospectively collected. Inclusion criteria were as follows: age >18 years old, patients who underwent total thyroidectomy, no change of operator during the surgery. The study group was divided into two groups: operated by general surgery specialists (385 patients-group 1) and operated by residents with the supervision of experienced general surgery specialists as assistants (130 patients-group 2). RESULTS: Demographic factors did not differ statistically between groups. Median operative time was 65 min (55-85 IQR) and 90 min (75-110 IQR) in groups 1 and 2, respectively (p < 0.001). Complications occurred in 97 (18.7%) patients in group 1 and 25 (19.3%) patients in group 2 (p = 0.893). Recurrent nerve palsy diagnosed with laryngoscopy was the most common complication - 10.2% and 9.2% of patients, respectively (p = 0.754). Permanent vocal paresis occurred in 2.3% and 3.2%, respectively (p = 0.786). Postoperative symptomatic hypocalcaemia occurred in 7% of patients in group 1 and 10% of patients in group 2 (p = 0.271). Logistic regression did not show that resident as the operator with or without intraoperative neuromonitoring is a risk factor for any complications. CONCLUSION: The results of the present study show that thyroidectomy performed by a general surgery resident under supervision can be as safe as the one performed by a specialist.

IMUMETER-A Convolution Neural Network-Based Sensor for Measurement of Aircraft Ground Performance.

The paper presents the development of the IMUMETER sensor, designed to study the dynamics of aircraft movement, in particular, to measure the ground performance of the aircraft. A motivation of this study was to develop a sensor capable of airplane motion measurement, especially for airfield performance, takeoff and landing. The IMUMETER sensor was designed on the basis of the method of artificial neural networks. The use of a neural network is justified by the fact that the automation of the measurement of the airplane's ground distance during landing based on acceleration data is possible thanks to the recognition of the touchdown and stopping points, using artificial intelligence. The hardware is based on a single-board computer that works with the inertial navigation platform and a satellite navigation sensor. In the development of the IMUMETER device, original software solutions were developed and tested. The paper describes the development of the Convolution Neural Network, including the learning process based on the measurement results during flight tests of the PZL 104 Wilga 35A aircraft. The ground distance of the test airplane during landing on a grass runway was calculated using the developed neural network model. Additionally included are exemplary measurements of the landing distance of the test airplane during landing on a grass runway. The results obtained in this study can be useful in the development of artificial intelligence-based sensors, especially those for the measurement and analysis of aircraft flight dynamics.

Application of the TDR Soil Moisture Sensor for Terramechanical Research.

This paper presents examples of the application of the TDR (Time-Domain Reflectometry) sensor in terramechanical research. Examples include the determination of soil moisture content during off-road vehicle mobility tests, the determination of snow density before and after the wheeling of a snow grooming machine and an airplane, as well as the monitoring of turf moisture on a grassy airfield for the analysis and prediction of safe and efficient flight operations (takeoff and landing). A handheld TDR meter was used in these experiments. Soil moisture data were correlated with the vehicle mobility index and a simple model for this correlation was derived. Using grassy airfield research, soil moisture data were related to meteorological impacts (precipitation, sunlight, etc.). Generally, it was concluded that the TDR meter, in its handheld version, was a useful tool in the performed research, but a field sensor that operates autonomically would be an optimal solution for the subject applications.

Application of GNSS/INS and an Optical Sensor for Determining Airplane Takeoff and Landing Performance on a Grassy Airfield.

The performance of a PZL 104 Wilga 35A airplane was determined and analyzed in this work. Takeoff and landing distances were determined by means of two different methods: one which utilized a Global Navigation Satellite System/Inertial Navigation System (GNSS/INS) sensor and another in which airplane ground speed was measured with the use of an optical non-contact sensor. Based on the airfield measurements, takeoff and landing distances as well as rolling resistance coefficients were determined for the used airplane on a grassy runway at the Radawiec airfield, located near Lublin, southeast Poland. The study was part of the "GARFIELD" project that is expected to deliver an online information system on grassy airfield conditions. It was concluded that both sensors were suitable for the aimed research. The results obtained in this study showed the effects of high grass upon the takeoff and landing performances of the test airplane. Also, the two methods were compared against each other, and the final results were compared to calculations of ground distances by means of the chosen analytical models.

Determining Wheel Forces and Moments on Aircraft Landing Gear with a Dynamometer Sensor.

This paper describes airfield measurement of forces and moments that act on a landing gear wheel. For the measurement, a wheel force sensor was used. The sensor was designed and built based on strain gage technology and was embedded in the left landing gear wheel of a test aircraft. The sensor is capable of measuring simultaneously three perpendicular forces and three moments and sends data to a handheld device wirelessly. For the airfield tests, the sensor was installed on a PZL 104 Wilga 35A multipurpose aircraft. The aircraft was towed at a "marching man" speed and the measurements were performed at three driving modes: Free rolling, braking, and turning. The paper contains results obtained in the field measurements performed on a grassy runway of the Rzeszów Jasionka Aerodrome, Poland. Rolling resistance of aircraft tire, braking friction, as well as aligning moment were analyzed and discussed with respect to surface conditions.

Is ITP really a desirable indication for teaching laparoscopic splenectomy? Cohort study.

Background: We aimed to evaluate the outcomes of laparoscopic splenectomy (LS) in patients with immune thrombocytopenic purpura (ITP) compared with operated for other indications. Methods: Retrospective cohort study of patients who underwent LS in 1998-2017. Group 1 consisted of 256 patients operated for ITP, and Group 2 of 231 operated for other indications. Primary outcome was procedure difficulty. Secondary was perioperative course (30 days of surgery). Results: Patients in Group 1 were younger (p < .001) with lower ASA (p < .001). The spleen was larger in Group 2 (p < .001). Operative time was longer in Group 2 [110 (80-150) vs. 90 (65-115) min; p < .001)]. Intraoperative blood loss was greater in Group 2 (p < .001). Conversions were higher in Group 2 (4.76 vs. 6.93%, p = .037), as were intraoperative complications (7.79 vs. 3.91%, p = .048). Morbidity, reoperations and mortality did not differ between groups (respectively, p = .899, .697, and .999). Median length of stay was similar (p = .211). Among the first 10 LSs performed by trainees, 63.66% were done for ITP. Later (after 11+ procedures) this dropped to 48.12% (p = .002). Conclusions: ITP may be a preferred indication for surgeons training for LS. Patients' characteristics and intraoperative factors allow an expectation for a relatively easy and hassle-free operation in those patients.

Laparoscopic Gastrectomy with Enhanced Recovery After Surgery Protocol: Single-Center Experience.

BACKGROUND Surgery remains the mainstay of gastric cancer treatment. It is, however, associated with a relatively high risk of perioperative complications. The use of laparoscopy and the Enhanced Recovery After Surgery (ERAS) protocol allows clinicians to limit surgically induced trauma, thus improving recovery and reducing the number of complications. The aim of the study is to present clinical outcomes of patients with gastric cancer undergoing laparoscopic gastrectomy combined with the ERAS protocol. MATERIAL AND METHODS Fifty-three (21 female/32 male) patients who underwent elective laparoscopic total gastrectomy due to cancer were prospectively analyzed. Demographic and surgical parameters were assessed, as well as the compliance with ERAS protocol elements, length of hospital stay, number of complications, and readmissions. RESULTS Mean operative time was 296.4±98.9 min, and mean blood loss was 293.3±213.8 mL. In 3 (5.7%) cases, conversion was required. Median length of hospital stay was 5 days. Compliance with ERAS protocol was 79.6±14.5%. Thirty (56.6%) patients tolerated an early oral diet well within 24 h postoperatively; in 48 (90.6%) patients, mobilization in the first 24 hours was successful. In 17 (32.1%) patients, postoperative complications occurred, with 7 of them (13.2%) being serious (Clavien-Dindo 3-5). The 30-day readmission rate was 9.4%. CONCLUSIONS The combination of laparoscopy and the ERAS protocol in patients with gastric cancer is feasible and allows achieving good clinical outcomes.

Foxp3+ lymphocyte count in Barrett's esophagus tissue is higher than in in amed esophageal tissue.

INTRODUCTION: The number of Foxp3+ lymphocytes is increased in patients with esophageal carcinoma. Little is known about Foxp3+ cells count in Barret's esophagus, which is a precancerous state for esophageal cancer. A i m: To count the number of Foxp3+ lymphocytes in tissue samples from patients with Barrett's and compare it with samples from individuals with esophagitis and esophageal cancer. MATERIALS AND METHODS: 43 patients were enrolled to the study: 14 with esophageal carcinoma, 15 with Barrett's esophagus and 14 with non-metaplastic esophagitis. Every patient undergone gastroscopy during which a tissue sample was taken. Foxp3+ lymphocytes and CD4+ lymphocytes were detected by using immunohistochemistry. RESULTS: Mean density of Foxp3+ cells in patients with esophagitis was 7.37/10HPF (range: 1-9), 18.5/10HPF (range: 5-29) and 26.8/10HPF (range: 16-40) in patients with dysplastic and non-dysplastic BE, respectively and 47.92/10HPF in individuals with esophageal a carcinoma. These intergroup differences turned out to be statistically significant (p = 0.000; Fig. 3). Patients, either with dysplasia or without, presented with significantly higher Foxp3+ cell counts than the subjects with esophagitis (p = 0.0003 and p = 0.0006, respectively). Also the number of Foxp3+ lymphocytes in esophageal adenocarcinoma specimens turned out to be significantly higher than in esophagitis (p = 0.0001), non-dysplastic and dysplastic BE tissue (p = 0.016 and p = 0.00047, respectively). CONCLUSIONS: Barrett's metaplasia, either with dysplasia or without, is associated with an evident increase in the number of Foxp3 lymphocytes within the esophagogastric junction mucosa. Restoration of lymphocyte balance in esophageal tissue might prevent malignant transformation of Barrett's metaplasia.

One hundred seventy-nine consecutive bariatric operations after introduction of protocol inspired by the principles of enhanced recovery after surgery (ERAS®) in bariatric surgery.

BACKGROUND: Obese patients are a very large high-risk group for complications after surgical procedures. In this group, optimized perioperative care and a faster recovery to full activity can contribute to a decreased rate of postoperative complications. The introduction of ERAS®-based protocol is now even more important in bariatric surgery centers. The results of our study support the idea of implementation of ERAS®-based protocol in this special group of patients. MATERIAL AND METHODS: This analysis included 170 patients (62 male/108 female, mean BMI 46.7 kg/m2) who had undergone laparoscopic bariatric surgery, and whose perioperative care was conducted according to a protocol inspired by ERAS® principles. Examined factors included oral nutrition tolerance, time until mobilization after surgery, requirements for opioids, duration of hospitalization, and readmission rate. RESULTS: During the first 24 postoperative hours, oral administration of liquid nutrition was tolerated by 162 (95.3%) patients and 163 (95.8%) were fully mobile. In 44 (25.8%) patients it was necessary to administer opioids to relieve pain. Intravenous liquid supply was discontinued within 24 hours in 145 (85.3%) patients. The complication rate was 10.5% (mainly rhabdomyolysis and impaired passage of gastric contents). The average time of hospitalization was 2.9 days and the readmission rate was 1.7%. CONCLUSIONS: The introduction of an ERAS® principles-inspired protocol in our center proved technically possible and safe for our patients, and allowed for reduced hospitalization times without increased rate of complications or readmissions.

Laparoscopic transperitoneal lateral adrenalectomy for malignant and potentially malignant adrenal tumours.

BACKGROUND: Laparoscopic adrenalectomy is still controversial in cases where malignancy is suspected. However, many proponents of this technique argue that in the hands of an experienced surgeon, laparoscopy can be safely performed. The aim of this study is to present our own experience with the application of laparoscopic surgery for the treatment of malignant and potentially malignant adrenal tumours. METHODS: Our analysis included 52 patients who underwent laparoscopic adrenalectomy in 2003-2014 due to a malignant or potentially malignant adrenal tumour. Inclusion criteria were primary adrenal malignancy, adrenal metastasis or pheochromocytoma with a PASS score greater than 6. We analyzed the conversion rate, intra- and postoperative complications, intraoperative blood loss and R0 resection rate. Survival was estimated using the Kaplan-Meier method. RESULTS: Conversion was necessary in 5 (9.7%) cases. Complications occurred in a total of 6 patients (11.5%). R0 resection was achieved in 41 (78.8%) patients and R1 resection in 9 (17.3%) patients. In 2 (3.9%) cases R2 resection was performed. The mean follow-up time was 32.9 months. Survival depended on the type of tumour and was comparable with survival after open adrenalectomy presented in other studies. CONCLUSIONS: We consider that laparoscopic surgery for adrenal malignancy can be an equal alternative to open surgery and in the hand of an experienced surgeon it guarantees the possibility of noninferiority. Additionally, starting a procedure with laparoscopy allows for minimally invasive evaluation of peritoneal cavity. The key element in surgery for any malignancy is not the surgical access itself but the proper technique.

Microstructural, Electrical, and Tribomechanical Properties of Mo-W-C Nanocomposite Films.

This study investigates the phase composition, microstructure, and their influence on the properties of Mo-W-C nanocomposite films deposited by dual-source magnetron sputtering. The synthesised films consist of metal carbide nanograins embedded in an amorphous carbon matrix. It has been found that nanograins are composed of the hexagonal ß-(Mo2 + W2)C phase at a low carbon source power. An increase in the power results in the change in the structure of the carbide nanoparticles from a single-phase to a mixture of the ß-(Mo2 + W2)C and NaCl-type α-(Mo + W)C(0.65≤k≤1) solid-solution phases. The analysis of electrical properties demonstrates that the nanograin structure of the films favours the occurrence of hopping conductivity. The double-phase structure leads to a twofold increase in the relaxation time compared to the single-phase one. Films with both types of nanograin structures exhibit tunnelling conductance without the need for thermal activation. The average distance between the potential wells produced by the carbide nanograins in nanocomposite films is approximately 3.4 ± 0.2 nm. A study of tribomechanical properties showed that Mo-W-C films composed of a mixture of the ß-(Mo2 + W2)C and α-(Mo + W)C(0.65≤k≤1) phases have the highest hardness (19-22 GPa) and the lowest friction coefficient (0.15-0.24) and wear volume (0.00302-0.00381 mm2). Such a combination of electrical and tribomechanical properties demonstrates the suitability of Mo-W-C nanocomposite films for various micromechanical devices and power electronics.

Effect of 160 MeV Xenon Ion Irradiation on the Tribological Properties and Crystal Structure of 100Cr6 Bearing Steel.

This is the first study ever to show the impact of high-energy 160 MeV xenon ion irradiation on the properties of 100Cr6 bearing steel. The projected range (Rp) of xenon ions is 8.2 µm. Fluence-dependent variations in the coefficient of friction and wear of the 100Cr6 steel material have been observed. These changes correlate with shifts in the crystal lattice constant and variations in the oxygen, carbon, and iron content in the wear track. Fluence-dependent changes in these parameters have been observed for the first time. Irradiation reduces stresses in the crystal lattice, leading to crystallite size increase. The modifications in the properties of 100Cr6 steel result from radiation-induced defects caused by electronic ion stopping. The degree of these modifications depends on the applied irradiation fluence. Furthermore, the use of a higher irradiation fluence value appears to mitigate the effects produced by a lower fluence.

A case of bilateral persistent sciatic artery with unilateral aneurysm: an 18-year period of graft patency after excision of aneurysm.

BACKGROUND: A persistent sciatic artery (PSA) is a rare vascular anomaly with an estimated incidence of 0.02-0.04% and with a high rate of complications such as aneurysm formation, thromboembolism, and ischemia, that may lead to amputation. CASE REPORT: We present a case of a female patient with complete symptomatic ambilateral PSA and with unilateral aneurysm. The aneurysm was excised and the PTFE graft was interposed at the aneurismal sac (femoro-popliteal bypass could not be performed because of the high degree hypoplasia of the superficial femoral artery). The graft endured continuous compression and stretching during regular daily life of the patient. At check-up 18 years after the operation, the Doppler ultrasound showed a patent graft and no new aneurismal dilatation of the sciatic artery. CONCLUSIONS: To our knowledge the follow-up of the presented case is the longest reported so far in the literature. The uneventful course of the patient confirms that classical aneurysmectomy still constitutes one of the treatment options of PSA aneurysm.

[An attempt to objectify the assessment of extension or recurrence of Dupuytren's disease on the basis of ultrasound]. / Próba obiektywizacji oceny nawrotu lub wznowy choroby Dupuytrena w oparciu o badanie ultrasonograficzne.

Dupuytren's contracture is a disease of unknown etiology, leading with time to decreased hand function caused by increasing contracture of fingers. Excision of contracted longitudinal palmar fascia constitutes the most important way of treatment. Due to fact that disease has progressive course in many patients recurrence (i.e. overgrowth of longitudinal palmar aponeurosis apart from the operated site) or extension (i.e. similar process affecting formerly operated site) occurs. An attempt to objectify the assessment of recurrence or extension of Dupuytren's disease on the basis of sonographic examination of palmar surface of the hand during distant (at least 24 months from surgery) followup constituted the aim of the study. 41 patients operated on from January 2000 to February 2009 in 2nd Department of General Surgery in Krakow due to Dupuytren's contracture constituted the study material. Mean age of the patients reached 62,78 years (SD +/- 9,32), and mean follow up time 5,74 years (SD +/- 2,90). Sonographic assessment was performed in 26 operated on left hands and 24 right hands. 9 patients had both hands operated on. In most of the patients during surgery the contralateral hand was also affected by the disease. Extension of Dupuytren's disease was found in 11 hands, recurrence--in 18 hands, while concurrent extension and recurrence was found in 17 hands. Extension usually was found on the radial side and affected mainly I interphalangeal space followed by disease affecting I and III ray of the hand. In one patient 2 independent foci of the disease were found within I interphalangeal space. Recurrences affected mainly ulnar side of the hand: V and IV rays of the hand. Concurrently found extension and recurrence affected 2 or 3 rays. In the cases of 3 rays affected extension dominated (2 rays vs. 1 ray of recurrence). On sonographic assessment mean diameters of lesions during distant follow- up were 12,69 x 4,62 x 3,95 [mm] with recurrent lesions being larger than mean values found in extensions. With partial fasciectomy being the most commonly performed operation in cases of Dupuytren's disease ultrasound can constitute very important technique of assessment of exacerbation of the lesions of palmar aponeurosis allowing for the choice of appropriate surgical technique for particular case, detection of postoperative extension and/or recurrence and for the cases clinically doubtful.

[Concomitance of Ledderhose's disease with Dupuytren's contracture. Own experience]. / Wspólistnienie choroby Ledderhose'a z przykurczem dupuytrena. Doswiadczenia wlasne.

INTRODUCTION: Ledderhose's disease is a rare fibromatosis affecting plantar aponeurosis. Clinical picture and risk factors resemble the ones found in much more common cases of Dupuytren's disease. MATERIAL AND METHODS: The group of 101 patients with Dupuytren's disease qualified for surgical treatment constituted material for the study. Within that group incidence of Ledderhose's disease was assessed on the basis of clinical and ultrasound examination. Estimation of the presence of risk factors common for both forms of fibromatosis was also evaluated. RESULTS: Ledderhose's disease was found in 15 patients (14.85%) suffering from Dupuytren's contracture. Bilateral Ledderhose's disease was found in 10 of them. Established risk factors were similar to the ones found in Dupuytren's disease--tobacco and alcohol dominated. Indications for the surgical treatment were limited to the symptomatic cases of the disease. Two feet in 4 patients were operated on. Surgical technique was presented in broad outline. Pain relief on walking and normalization of feet pressure distribution were achieved in all cases.

Changes in the localization of perforated peptic ulcer and its relation to gender and age of the patients throughout the last 45 years.

BACKGROUND: Throughout recent decades there has been noticeable change in the incidence of peptic ulcer disease and its complications. The aim of the present study was to determine the character of changes over the last 45 years in the localization of perforation, in patient age, and in patient gender. METHODS: A group of 881 patients admitted to the Second Department of General Surgery in Krakow, Poland, from 1962 to 2006 were included in the study and constituted the material for the analysis. The study was divided into three time periods (1962-1976, 1977-1991, and 1992-2006) to allow statistical analysis of trends. RESULTS: The general incidence of perforations of peptic ulcer did not show changes; however, the percentage of women with perforated duodenal ulcer markedly increased. Patients with perforated stomach ulcer--regardless of gender--and females suffering from perforated duodenal ulcer were, on the average, about 10 years older than males with perforated duodenal ulcers. The mean age of male and female patients with perforated duodenal ulcer over the last 45 years showed an insignificant upward trend. CONCLUSIONS: (1) The percentage of women with perforated duodenal ulcer continuously and statistically significantly rose. (2) Men with perforated duodenal ulcer were significantly younger than other patients. (3) The mean ages of male and female patients with perforated duodenal ulcer over the last 45 years showed an insignificant upward trend.

[Use of the percutaneous drainage in the treatment of patients with hepatic abscesses]. / Zastosowanie drenazu przezskórnego w leczeniu chorych z ropniami watroby.

AIM OF THE STUDY: The aim of this study was to review our results in managing liver abscess with the use of sonographically-guided percutaneous drainage. MATERIAL AND METHODS: There were 24 patients (including 12 male and 12 female patients) with liver abscesses treated from 1993 to 2009 in our department. Mean age in the male group amounted to 52 (17-70), while in the female group - 60 (46-72). The group of 22 patients (91,6%) were treated with the use of percutaneously inserted "pigtail drain". RESULTS: The group of 22 patients (11 male and 11 female patients) was treated with the use of percutaneous sonographically-guided drainage. Eschericha coli constituted the most common etiological factor isolated from the purulent content. An average drainage time amounted to 9,5 days. Percutaneous drainage proved ineffective only in 4 patients (2 male and 2 female). In 2 of those cases failure was due to recurrent obstruction of the catheter and in remaining 2--due to migration of the drain outside the abscess. 2 of those patients were treated successfully with another sonographically-guided drainage, while 2 patients required open surgical operation. CONCLUSIONS: Percutaneous sonographically-guided drainage together with antimicrobial therapy constitutes valuable method of choice in the management of liver abscess. The technique has small morbidity and complication ratio allowing avoidance of more invasive surgical interventions.

[Tension-free technique for the repair of strangulated abdominal hernias]. / Beznapieciowa metoda leczenia uwieznietych przepuklin powlok brzucha.

There are just few studies regarding the use of tension-free techniques during the emergency operations of strangulated hernias among all the articles on the subject of surgical herniorrhaphy. Assessment of safety of the use of mono- or double-filament polypropylene mesh for the repair of strangulated hernia constituted the aim of the study. There were 81 inguinal and 34 other hernias (mostly incisional) in the group of 115 surgically treated patients with strangulated abdominal wall hernias. During the surgical operation in 84 patients strangulated bowel loop was reduced, 22 patients were treated with reduction of larger omentum, 7 patients required bowel resection (including 2 resections of Meckel diverticulum) and 2 resections of the omentum. All patients received prophylactic dose of broad-spectrum antibiotic during the surgical procedure and for 2-4 days after the operation. There were 15 cases of surgical site complications noted. Only two such cases (purulent infection in two patients and necrosis of wound margins in one) constituted potential threat to the implant. The incidence of local surgical complications was somewhat lower in the group of inguinal hernias as compared to the others (11.1% vs. 17.6%). The data from our study confirm the fact that mono- or double-filament polypropylene mesh can be safely used for the repair of strangulated hernia and the risk of local surgical complications is scant.

Formation of Si-Rich Interfaces by Radiation-Induced Diffusion and Microsegregation in CrN/ZrN Nanolayer Coating.

A combination of coating deposition and consequent ion implantation could be beneficial in wear-resistant antifriction surface design and modification. In the present paper, the effects of low-energy 60 keV Si-ion implantation on multinanolayered CrN/ZrN grown on a stainless-steel substrate have been investigated. Complementary experimental (X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive spectroscopy, secondary ion mass spectrometry) and theoretical (first-principles) methods have been employed to investigate the structure, phase, and composition under a 1 × 10-17 cm-2 irradiation dose. This study has revealed a moderate radiation-tolerance of the CrN/ZrN system, with a 26 nm bilayer period, where the effective ion range after irradiation was below 110 nm. Within the ion range, a decrease in composition homogeneity and structure crystallinity has been found. Si negative ions have been distributed asymmetrically with peak concentrations (10 and 6%) occupying the interfaces between the CrN and ZrN layers. First-principles investigations of the CrN/ZrN(001) heterostructures were carried out to validate the experimental results, which showed that the alignment of Si-rich interfaces closer to chromium layers is a consequence of the lower substitution energy of CrN rather than ZrN. Thus, strong Si-Cr bindings and difference in displacement energies of ZrN and CrN have been attributed as the main factors in Si-rich interface formation. The pin-on-ball tribological test results have exposed the enhancement in wear resistance and the friction coefficient of nanoscale coating via amorphous Si particles descending from interfacial areas and acting as a third-body.

Ghrelin in diseases of the gastric mucosa associated with Helicobacter pylori infection.

BACKGROUND: Ghrelin is a hormone produced by neuroendocrine cells of gastric mucosa. Its concentration changes in cases of Helicobacter pylori (H. pylori) infection of stomach, but the relation between the expression of plasma and mucosal ghrelin content and H. pylori infection is not completely defined. This study was designed to determine the changes in plasma and gastric mucosa ghrelin concentrations in diseases of gastric mucosa depending upon the H. pylori infection. MATERIAL/METHODS: The following groups were included; Group 1. patients with gastric cancer and concomitant H. pylori infection (N=25); Group 2. patients with antral gastritis with H. pylori infection and concomitant duodenal peptic ulcer (N=18); Group 3. patients with atrophic gastritis of both the fundus and the body of the stomach without H. pylori infection (N=10); Group 4. control group consisting of patients without morphological and histological lesions of gastric mucosa and without H. pylori infection (n=25). Endoscopic biopsies of gastric mucosa of fundus, body and pyloric region were obtained in all tested groups. In patients suffering from gastric cancer biopsies of tumor were also taken. The ghrelin concentrations were measured by specific RIA. Biopsy specimens were examined to assess ghrelin mRNA expression in intact gastric mucosa and gastric cancer. RESULTS: The study showed significant influence of H. pylori infection on ghrelin plasma concentrations. The highest ghrelin concentrations were found in patients of the group 2 (average 503 pg/mL (95% CI: 285-886). Ghrelin concentrations were found to fall to the lowest values in the group 3 (average 144 pg/mL (95% CI: 93-222). In the group 1, the ghrelin concentration averaged 203 pg/mL (95% CI: 161-257), while in the group 4 (control group) - 255 pg/mL; 95% (CI: 160-406). The study proved that gastric cancer does not exert any ghrelin-production activity, as confirmed by RT-PCR examination of biopsy specimens of the cancer. CONCLUSIONS: This study shows that the presence of H. pylori in the stomach with peptic ulcer increases plasma ghrelin levels, whereas in gastric cancer and atrophic gastritis it is accompanied by a marked decrease in plasma and cancer tissue levels of ghrelin.