Temperature-dependent dielectric relaxation and hydrophobicity of aqueous alanine using time domain reflectometry

Physical, chemical and microbiological stability of the materials is affected by the rotational and translational mobility of free and hydrated water. The role of water in areas such as protein hydration and enzyme activity, food technology, lyophilization and polymers hydration is, therefore, important and can be well understood in terms of dielectric relaxation spectroscopy. Concentration and temperature-dependent hydrophobicity of amino acid is reflected in their tendencies to appear in appropriate positions in proteins. Therefore, to gain more insights on the temperature and concentration dependence of hydrophobicity and structural properties of amino acid, dielectric relaxation of aqueous alanine have been studied in the temperature region 303.15 K to 278.15 K. Time domain spectroscopy have been used in the frequency range of 10 MHz to 30 GHz and in the concentration range 0.18708 ≤ c/M ≤ 0.74831. Two relaxation processes namely the low-frequency relaxation (l) and the high-frequency relaxation (h) has been detected for the aqueous alanine. Dielectric parameters such as static dielectric constant (εj), relaxation time (τj) dipole moments (û) and correlation factor (g) have been studied to investigate molecular interaction between alanine and water. The number of water molecules irrotationally bond by the solute molecules (Zib) was also determined to examine the hydrophobicity of alanine which was found more hydrophobic towards low temperatures and concentrations. Thermodynamic parameters calculated are also supported well for the hydrophobic behaviour of alanine towards low temperatures and concentrations.Communicated by Ramaswamy H. Sarma.

The detection of microscopically disseminated cancer cells in the abdominal cavity by intraoperative lavage cytology combined with an immunocytochemical method in gastric cancer

This study was conducted to clarify the possible role of the immunocytochemical examination of intraoperative lavage cytology in gastric cancer. The expression of CA19-9, STN, SLX and CEA in tissues were examined in 70 patients with advanced gastric cancer who underwent gastric resection. The tissue sections were processed with the hematoxylin and eosin staining and immunostaining using the avidin-biotin-peroxidase complex (ABC) method. Fifty one patients underwent the lavage cytology. The cytologic samples were stained by the conventional Papanicolau method and ABC immunocytochemical method. Expression of CEA was detected at obviously higher frequency than those of the 3 carbohydrate antigens. The method combined with 4 antibodies increased the detection rate to 97.2%. Conventional lavage cytology was positive in 16 out of 51 patients. The diagnosis of class III in four patients was changed to class V through the immunocytochemical examination. The immunocytochemical examination of lavage cytology is very useful to verify the microscopically disseminated cancer cells in gastric cancer.

Postoperative functional evaluation of pylorus-preserving gastrectomy for early gastric cancer compared with conventional distal gastrectomy

BACKGROUND

Malnutrition, gallbladder dysfunction, dumping syndrome, reflux esophagitis, and gastritis of the remnant stomach are unfavorable sequelae in patients undergoing gastrectomy. Operative procedures should be improved to ensure such patients a satisfactory quality of life.

METHODS

After operation, gallbladder function, reflux gastritis, gastric emptying, and caloric intake were evaluated in 20 patients with early gastric cancer undergoing pylorus-preserving gastrectomy (PPG) and 25 patients undergoing conventional distal gastrectomy (CDG).

RESULTS

The resting gallbladder area increased significantly after CDG. In contrast, after PPG the gallbladder area showed no significant change and the contraction rate decreased slightly. After CDG, emptying was much more rapid for the first 30 minutes after ingestion of a meal. Although delayed emptying was observed early after PPG, the rate of emptying increased with time. Gastric pH was lower and gastric mucosal injury was milder in patients undergoing PPG. These results are attributed to preserved pyloric function. The caloric intake and changes in body weight after operation were similar in both the CDG and PPG groups.

CONCLUSIONS

PPG has advantages over CDG in terms of gallbladder function, the condition of the remnant stomach, and gastric emptying, PPG should be used in carefully selected patients with early gastric cancer to improve their quality of life.