[Analysis of etiology and complications in children with stage 5 chronic kidney disease]

Objective: To investigate the etiology, complications, and prognostic factors of stage 5 chronic kidney disease (CKD5) in children. Methods: A case series study was conducted to retrospectively analyze the general situation, clinical manifestations, laboratory tests, genetic testing, and follow-up data (until October 2022) of 174 children with CKD5 who were diagnosed and hospitalized at the Children's Hospital of Chongqing Medical University from April 2012 to April 2021. The characteristics of complications in the children were compared based on age, gender, and etiology. Based on the presence or absence of left ventricular hypertrophy (LVH), patients were divided into LVH group and non LVH group for analyzing the influencing factors of cardiovascular disease. Patients were also divided into death group and survival group, peritoneal dialysis group and hemodialysis group based on the follow-up data for analyzing the prognostic factors. The chi-square test, independent sample t-test, Fisher exact probability test, Mann-Whitney U test and Kruskal Wallis test were used to analyze data among different groups. Multivariate Logistic regression analysis was used to identify the prognostic factors. Results: A total of 174 children with CKD5 were enrolled in the study (96 boys and 78 girls), aged 11.2 (8.2, 13.0) years. Congenital kidney and urinary tract malformations (CAKUT) were the most common causes of the CKD5 (84 cases, 48.3%), followed by glomerular diseases (83 cases, 47.7%), and among which 28 cases (16.1%) were hereditary glomerular diseases. The common complications of CKD5 included anemia (98.2%, 165/168), mineral and bone disorder in chronic kidney disease (CKD-MBD) (97.7%, 170/174), lipid metabolism disorders (87.5%, 63/72), hypertension (81.4%, 127/156) and LVH (57.6%,57/99). The incidences of hypertension in primary glomerular disease were higher than that in CAKUT(93.8%(30/32) vs.73.7%(56/76),χ2=5.59,P<0.05). The incidences of hypertension in secondary glomerular disease were higher than that in CAKUT and that in hereditary kidney disease (100.0%(20/20) vs. 73.7%(56/76), 68.2%(15/22), both P<0.05). The incidence of hypocalcemia in CAKUT, primary glomerular disease, and hereditary kidney disease was higher than that in secondary glomerular disease (82.1%(69/84), 88.2%(30/34), 89.3%(25/28) vs. 47.6%(10/21), χ2=10.21, 10.75, 10.80, all P=0.001); the incidence of secondary hyperparathyroidism in women was higher than that in men (80.0%(64/80) vs. 95.0%(57/60), χ2=6.58, P=0.010). The incidence of LVH in children aged 6-<12 was higher than that in children aged 12-18 (73.5%(25/34) vs. 43.1%(22/51), χ2=7.62, P=0.006). Among 113 follow-up children, the mortality rate was 39.8% (45/113). Compared to the survival group, the children in the death group had lower hemoglobin, higher blood pressure, lower albumin, lower alkaline phosphatase and higher left ventricular mass index ((67±19) vs. (75±20) g/L, 142 (126, 154) vs. 128(113, 145) mmHg(1 mmHg=0.133 kPa), (91±21) vs. (82±22) mmHg, 32 (26, 41) vs. 40 (31, 43) g/L, 151 (82, 214) vs. 215 (129, 37) U/L, 48 (38, 66) vs. 38(32, 50) g/m2.7,t=2.03, Z=2.89, t=2.70, Z=2.49, 2.79, 2.29,all P<0.05), but no independent risk factors were identified (all P>0.05). The peritoneal dialysis group had better alleviation for anemia, low calcium, and high phosphorus than the hemodialysis group ((87±22) vs. (72±16) g/L, (1.9±0.5) vs. (1.7±0.4) mmol/L, (2.2±0.7) vs. (2.8±0.9) mmol/L, t=2.92, 2.29, 2.82, all P<0.05), and the survival rate of the peritoneal dialysis group was significantly higher than that of the hemodialysis group (77.8% (28/36) vs. 48.4% (30/62), χ2=8.14, P=0.004). Conclusions: CAKUT is the most common etiology in children with CKD 5, and anemia is the most common complication. The incidence of complications in children with CKD 5 varies with age, gender and etiology. Anemia, hypertension, hypoalbuminemia, reduced alkaline phosphatase and elevated LVMI may be the prognostic factors in children with CKD5. Peritoneal dialysis may be more beneficial for improving the long-term survival rate.

[Intravenous infusion of methylene blue to visualize the ureter in laparoscopic colorectal surgery]

Objective: Intraoperative localization of the ureter can contribute to accurate dissection and minimize ureteral injury in colorectal surgery. We aim to summarize a single center's experience of fluorescence ureteral visualization using methylene blue (MB) and explore its visualization efficiency. Methods: This is a descriptive case-series-study. Clinical data of patients who had undergone laparoscopic colorectal surgery and fluorescence visualization of the ureter in the Gastrointestinal Surgery Department of Guangdong Provincial People's Hospital from March 2022 to May 2022 were retrospectively collected. Patients with incomplete surgery videos, renal insufficiency, or allergic reactions were excluded. MB was infused with 0.9% NaCl at 1.0 mg/kg in 100 mL of normal saline for 5 to 15 minutes during laparoscopic exploration. Imaging was performed using a device developed in-house by OptoMedic (Guangdong, China) that operates at 660nm to achieve excitation of MB. Clinical information, MB dosage, rate of successful fluorescence, time to fluorescence, operation time, blood loss, intraoperative blood oxygen levels, pathological staging, changes in renal function, and post-operative complications were retrospectively analyzed. Results: The study cohort comprised 27 patients (24 men and 3 women) with an average age of (60.25±16.95) years and an average body mass index of (21.72±3.42) kg/m². The dosage of MB was 0.3-1.0 mg/kg and the infusion time was 5-15 minutes. Fluorescence signals were detected in all patients. The median time to signal detection was 20 (range, 10 to 40) minutes after MB infusion. The range of intraoperative blood oxygen fluctuation averaged 2.5% (range, 0 to 7.0%). The median change in creatine concentration was -1.3 (range, -17.2 to 29.2) µmol/L. No patients had complications associated with use of MB. Fluorescence visualization of the ureter was very valuable clinically in two patients (thick mesentery, stage T4). Conclusion: MB is a safe and effective means of visualizing the ureter by fluorescence during laparoscopic colorectal surgery, especially when the procedure is difficult. MB in a dosage of less than 1 mg/kg can slowly infused for more than 5 minutes during laparoscopic exploration. During the infusion, attention must be paid to blood oxygen fluctuations.

Diets varying in ratio of sweet sorghum silage to corn silage for lactating dairy cows: Feed intake, milk production, blood biochemistry, ruminal fermentation, and ruminal microbial community

The objective of this study was to investigate the effects of partial substitution of corn silage (CS) with sweet sorghum silage (SS) in the diets of lactating dairy cows on dry matter (DM) intake, milk yield and composition, blood biochemistry, and ruminal fermentation and microbial community. Thirty mid-lactation Holstein dairy cows [mean ± standard deviation; 639 ± 42.0 kg of body weight; 112 ± 24.0 d in milk (DIM)] were assigned to 3 groups (n = 10/treatment) by considering parity, milk yield, and DIM. The cows were fed ad libitum total mixed rations containing 55% forage and 45% concentrate, with only the proportion of CS and SS varying in 3 treatments (DM basis): SS0 (0% substitution of CS), 40% CS and 0% SS; SS25 (25% substitution of CS)_, 30% CS and 10% SS; and SS50 (50% substitution of CS)_, 20% CS and 20% SS. Dry matter intake and milk protein concentration tended to linearly decrease with increasing proportion of SS in the diet. Yields of milk (mean ± standard deviation, 30.9 ± 1.12 kg/d), 4% fat-corrected milk (30.0 ± 0.81 kg/d), energy-corrected milk, milk protein, lactose, and total solids, concentrations of milk fat, lactose, somatic cell counts, and milk efficiency did not differ among diets. The concentrations in blood of urea nitrogen, phosphorus, aspartate aminotransferase, and malondialdehyde linearly increased with increasing SS proportion. Blood IgA decreased with increasing SS substitution rate, but blood IgG and IgM were not different among diets. Ruminal pH did not differ among diets, whereas ruminal NH₃-N concentration quadratically changed such that it was greater for SS50 than for SS0 and SS25. Molar proportions of propionate and acetate to propionate ratio were less for SS25 than for SS0. Although the diversity and general ruminal microbial community structure were not altered by partially replacing CS with SS, the relative abundances of predominant bacteria were affected by diets at the phylum and genus levels. Firmicutes and Bacteroidetes were dominant phyla in the ruminal bacterial community for all diets, and their relative abundance linearly decreased and increased, respectively, with increasing SS substitution rate. Prevotella_1 and Ruminococcaceae_NK4A214_group were detected as the most and the second most abundant genera, with their relative abundance linearly increased and decreased, respectively, with increasing SS substitution rate. The relative abundance of Fibrobacter linearly increased with increasing dietary SS proportion, with greater abundance observed for SS25 and SS50 than for SS0. These results suggest that substitution of CS with SS altered the relative abundances of some predominant bacteria; however, these changes had little effect on ruminal fermentation and milk yield. Under the current experimental conditions, substituting up to 50% of CS with SS had no negative effects on milk yield, indicating that SS can partially replace CS in the diets of high-producing lactating dairy cows without adding extra grain, when diets are fed for a short time. As the effects of substituting CS with SS depend upon the chemical composition and digestibility of these silages and the nutrient requirements of the cows, additional grain may be required in some cases to compensate for the lower starch content of SS.

[Safety and feasibility of indocyanine green injection through accessory incision in laparoscopic right hemicolectomy]

Objective: To explore the safety and feasibility of indocyanine green (ICG) injection through accessory incision in laparoscopic right hemicolectomy. Methods: A descriptive case series study was carried out. Clinicopathological data of 29 patients with colon cancer undergoing right hemicolectomy at Department of General Surgery, Guangdong Provincial People's Hospital were retrospectively analyzed. All the patients received ICG injection through accessory incision at the beginning of operation. Results: Among 29 patients, 13 were male and 16 were female with a mean age of (60.8±7.7) years and mean body mass index of (24.3±2.8) kg/m(2); 3 were stage I, 19 were stage II, 7 were stage III. Pericolic, intermediate and main lymph nodes could be detected under near infrared fluorescence imaging (NIRFI) in all the cases. No.6 lymph nodes were observed in 3 cases, while no lymph nodes around superior mesenteric vein (SMV) were found. The average number of fluorescent lymph node was 14.2±6.1. The average developing time of fluorescence was (36.2±3.7) minutes. The average number of harvested lymph nodes was 22.4±8.2. There was no extravasation of imaging agent during the operation, and there were no intraoperative complications such as allergies, massive abdominal bleeding, peripheral organ damage, etc. Operative time was (113.1±10.7) minutes, blood loss during operation was (22.4±3.9) ml, ambulatory time was (1.2±0.4) days, time to the first flatus was (1.7±0.7) days, time to the first fluid diet was (0.7±0.4) days, and postoperative hospital stay was (5.8±1.5) days. No operation-associated complications such as anastomotic bleeding, anastomotic leakage, peritoneal bleeding, peritoneal infection, incision infection occurred after operation. Conclusion: ICG injection through accessory incision in laparoscopic right hemicolectomy is safe and feasible.

[Current practice patterns of preoperative bowel preparation in elective colorectal surgery: a nation-wide survey of Chinese surgeons]

Objective: To understand the current practice of preoperative bowel preparation in elective colorectal surgery in China. Methods: A cross-sectional questionnaire survey was conducted through wechat. The content of the questionnaire survey included professional title of the participants, the hospital class, dietary preparation and protocol, oral laxatives and specific types, oral antibiotics, gastric intubation, and mechanical enema before elective colorectal surgery. A stratified analysis based on hospital class was conducted to understand their current practice of preoperative bowel preparation in elective colorectal surgery. Result: A total of 600 questionnaires were issued, and 516 (86.00%) questionnaires of participants from different hospitals, engaged in colorectal surgery or general surgeons were recovered, of which 366 were from tertiary hospitals (70.93%) and 150 from secondary hospitals (29.07%). For diet preparation, the proportions of right hemicolic, left hemicolic and rectal surgery were 81.59% (421/516), 84.88% (438/516) and 84.88% (438/516) respectively. The average time of preoperative dietary preparation was 2.03 days. The study showed that 85.85% (443/516) of surgeons chose oral laxatives for bowel preparation in all colorectal surgery, while only 4.26% (22/516) of surgeons did not choose oral laxatives. For mechanical enema, the proportions of right hemicolic, left hemicolic and rectal surgery were 19.19% (99/516), 30.04% (155/516) and 32.75% (169/516) respectively. Preoperative oral antibiotics was used by 34.69% (179/516) of the respondents. 94.38% (487/516) of participants were satisfied with bowel preparation, and 55.43% (286/516) of participants believed that preoperative bowel preparation was well tolerated. In terms of preoperative oral laxatives, there was no statistically significant difference between different levels of hospitals [secondary hospitals vs. tertiary hospitals: 90.00% (135/150) vs. 84.15% (308/366), χ(2)=2.995, P=0.084]. Compared with the tertiary hospitals, the surgeons in the secondary hospitals accounted for higher proportions in diet preparation [87.33% (131/150) vs. 76.78% (281/366), χ(2)=7.369, P=0.007], gastric intubation [54.00% (81/150) vs. 36.33% (133/366), χ(2)=13.672, P<0.001], preoperative oral antibiotics [58.67% (88/150) vs. 24.86% (91/366), χ(2)=12.259, P<0.001] and enema [28.67% (43/150) vs. 15.30% (56/366), χ(2)=53.661, P<0.001]. Conclusion: Although the preoperative bowel preparation practice in elective colorectal surgery for most of surgeons in China is basically the same as the current international protocol, the proportions of mechanical enema and gastric intubation before surgery are still relatively high.

[Feasibility and safety of the medial approach "four-step method" in the laparoscopic mobilization of splenic flexure]

Objective: To investigate the feasibility and safety of the medial approach "four-step method" in the laparoscopic mobilization of splenic flexure. Methods: A retrospective cohort study was performed. Clinical data of 157 colorectal cancer patients undergoing the medial approach "four-step method" in the laparoscopic mobilization of splenic flexure at Gastrointestinal Surgical Department of Guangdong Provincial People's Hospital from July 2015 to June 2018 were retrospectively analyzed. Of 157 cases, 17 were transverse colon cancer, 94 were descending colon cancer, 25 were sigmoid cancer and 21 were rectal cancer; 89 were male and 68 were female; mean age was (61.8±10.3) years and mean body mass index was (23.2±3.7) kg/m(2). The medial approach "four-step method" in the laparoscopic mobilization of splenic flexure was performed as follows: (1) The root vessels were treated with the "provocation" technique to expand the Toldt's gap. This expansion was extended from the lateral side to the peritoneum reflex of left colonic sulcus, from the caudal side to the posterior rectal space, and from the cephalad side to the lower edge of pancreas. (2) The left colonic sulcus was mobilized, converging with the posterior Toldt's gap. Mobilization was carried out from cephalad side to descending colon flexure, freeing and cutting phrenicocolic ligament and splenocolic ligament, and from caudal side to peritoneal reflex. (3) Gastrocolic ligament was moblized. Whether to enter the great curvature of stomach omentum arch when the gastrocolic ligament was cut, that was, whether to clean the fourth group of lymph nodes, should be according to the tumor site and whether serosal layer was invaded. (4) Transverse mesocolon was moblized and transected at the lower edge of the pancreatic surface, merging with the posterior Toldt's gap, and from lateral side to lower edge of the pancreatic body, merging with the lateral left paracolonic sulcus. Safety and short-term clinical efficacy of this surgical procedure was summarized. Results: All the patients completed this procedure. During operation, 3 cases were complicated with organ injury, including 1 case of colon injury, 1 case of spleen injury and 1 case of pancreas injury. No operative death and conversion to open surgery was found. The average operation time was (147.5±35.1) minutes, the average intra-operative blood loss was (40.8±32.7) ml and the average number of harvested lymph node was (16.1±5.8), including (4.0±2.3) of positive lymph nodes. The first exhaust time after surgery was (41.3±20.6) hours, the fluid intake time was (1.5±1.3) days, the postoperative hospital stay was (5.2±2.3) days. Eight (5.1%) cases developed postoperative complications, and all were improved and discharged after conservative treatments. According to the TNM classification system, postoperative pathology revealed that 31 patients were stage I, 51 were stage II, 53 were stage III, 22 were stage IV. Conclusion: The medial approach "four-step method" is safe and feasible, which can effectively decrease the operation difficulty of the laparoscopic mobilization of the splenic flexure.

[The significance of lymphocyte to monocyte ratio in peripheral blood of patients with benign and malignant laryngeal lesions]

Objective:The aim of this study is to investigate the value of preoperative peripheral blood lymphocyte to monocyte ratio (LMR) in differentiating laryngeal squamous cell carcinoma (LSCC), laryngeal precancerous lesions (LPL) and laryngeal benign lesions (LBL). Method:Four hundred and five cases of laryngeal lesions diagnosed by pathology (154 cases of LSCC, 83 cases of LPL and 168 cases of LBL) were collected. LSCC group was further divided into T1 group, T2 group and T3-4 group based on T stage. The levels of neutrophils, lymphocytes, monocytes, hemoglobin, platelet and other blood indexes were measured, as well as compared the LMR, neutrophil to lymphocyte ratio (NLR) and other parameters in each group. Result:The LMR and NLR in LBL, LPL and LSCC groups was 4.88±1.65 and 4.61±1.59, 3.92±1.77 and 2.11±0.79, 2.08±0.77 and 2.63±1.69, respectively. The LMR in the LSCC group was significantly lower than those in the LBL and LPL group (P<0.01), whereas the NLR was significantly higher than those in LBL and LPL group (P<0.05). Either LMR or NLR between the LBL and LPL group was not statistically different (P>0.05). The LMR of patients with local advanced (T3-4) stage in the LSCC group was lower than that in the early or medium stage (T1-2), while the NLR was higher and the difference was statistically significant (P<0.05). There was no significant difference in platelet, white blood cell and neutrophil count between LBL, LPL and LSCC (P>0.05). Conclusion:We, for the first time, compared LMR in different laryngeal lesions and found that LMR and NLR as a systemic inflammatory index have a certain reference value for to differentiate LSCC from LPL and LBL.

Effects of maternal protein or energy restriction during late gestation on antioxidant status of plasma and immune tissues in postnatal goats

Maternal malnutrition can have temporary or long-lasting effects on development and physiological function of offspring. Our objective was to investigate whether maternal protein or energy restriction in late gestation affects the antioxidant status of plasma, immune organs (thymus and spleen), and natural barrier organs (jejunum) in neonatal goats and whether the effects could be reversed after nutritional recovery. Forty-five pregnant goats (Liuyang Blacks) of similar age (2.0 ± 0.3 yr) and BW (22.2 ± 1.5 kg at d 90 of gestation) were assigned to 3 dietary treatments during late gestation: control (ME = 9.34 MJ/kg and CP = 12.5%, DM basis), 40% protein restricted (PR), and 40% energy restricted (ER) until parturition, after which offspring received the normal diet for nutritional recovery. Plasma and tissues of kids were sampled to determine antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and catalase (CAT)] and gene expression of antioxidant enzymes (Cu/Zn-SOD [SOD1], CAT, and peroxiredoxin 2 [PRDX2]). Maternal protein or energy restriction decreased (P < 0.05) SOD activities in plasma, liver, thymus, and spleen and SOD1 expression in thymus, and maternal energy restriction also decreased (P < 0.05) plasma GSH-Px activity and expressions of SOD1 and CAT in liver at birth. After nutritional recovery of 6 wk, SOD activities in thymus (both in PR and ER) and spleen (only in PR) were greater (P < 0.05), but CAT activity of thymus (both in PR and ER) and CAT expression (only in ER) were less (P < 0.01) than those in control. After nutritional recovery of 22 wk, SOD1 and PRDX2 expression in thymus (both in PR and ER) and SOD1 expression in liver (only in ER) were greater (P < 0.05) whereas CAT expression in thymus (both in PR and ER) was less (P < 0.001) than in control. The current results indicate that maternal protein or energy restriction can decrease the antioxidant capacity of the neonatal kids and result in an imbalance of SOD and hydrogen peroxide-inactivating systems in thymus, even after 6 or 22 wk of nutritional recovery.

Polysaccharide-K (PSK) in cancer--old story, new possibilities?

Polysaccharide-K (PSK, Krestin) is one of the most commonly used medicinal mushroom extracts with a long history as an additive in cancer therapy in Asia, especially in Japan. PSK has a documented anti-tumor activity both in vitro and in vitro, in various types of cancers, including colorectal, gastric, breast, liver, pancreatic, and lung cancer. Despite PSK having been studied for about 40 years as an immune modulator and biological response modifier, the mechanisms of action by PSK have not yet been clearly and completely elucidated. This review aims to provide an up-to-date account for the effects of PSK in cancer with the hope of thereby providing an increased understanding of the molecular mechanisms of PSK and also its potential as an additive in modern cancer therapy.

Using Carbon Nanotubes to Absorb Low-Concentration Hydrogen Sulfide in Fluid

Hydrogen sulfide is a colorless and flammable gas under room temperature. Usually hydrogen sulfide is considered to be toxic; however, the recent research revealed that hydrogen sulfide in the cardiovascular system plays the role of a vascular dilator. The physiological role of hydrogen sulfide depends on its in vivo level. As such, the measurement of hydrogen sulfide with nano-quantity resolution becomes an important subject. Existing methods generally require bulky samples and are invasive and offline. It will be significantly helpful to measure hydrogen sulfide with a small amount of tissue in a noninvasive method The first attempt was to take a blood or serum sample with a trace amount to examine the interaction between hydrogen sulfide and carbon nanotube. The carbon nanotube is chosen because of a known fact that hydrogen sulfide can be adsorbed by activated carbon. The carbon nanotube is an excellent activated carbon in this regard. Fluorescence intensity of the carbon nanotube with and without immersion of it in a hydrogen sulfide medium was examined in the study. It was found that the intensities increase as the concentrations of hydrogen sulfide increase. Furthermore, the concentration of 10 microM hydrogen sulfide in water was successfully measured.

Genetic profile of 15 STR loci in the Min Nan population in Southeast China

Genetic profile of 15 short tandem repeats (STR) loci were determined in a Chinese Han population from the Min Nan mountainous area, Southeast China.

Characterization of diatomaceous silica by Raman spectroscopy

The network characteristic of a selection of diatomaceous silica derived from China has been investigated using Raman spectroscopy. Before any thermal treatment of the sample, two prominent bands of 607 and circa 493 cm(-1) are resolved in the Raman spectra of diatomaceous silica, corresponding to the (SiO)3-ring breathing mode of D2-line and the O3SiOH tetrahedral vibration mode of D1-line, respectively. This is more similar to the pyrogenic silica rather than the silica gel. For the latter, to obtain a (SiO)3-ring, the sample must be heated between 250 and 450 degrees C. Significant difference is also found between the diatomaceous silica and other natural silicas, e.g. in the Raman spectra of sedimentary and volcanic opals, neither D1 nor D2 band is detected in previous reports.

Roles of PI3K in neutrophil function

Neutrophils are terminally differentiated cells that play a vital role in host defense. It has recently become evident that phospholipid regulation plays an import role in many neutrophil functions. We review the regulation of neutrophil functions such as chemotaxis, superoxide production, and phagocytosis by phosphatidylinositol-3,4,5-trisphosphate (PIP3), which is generated in neutrophils by PI3K(gamma). Several lines of evidence are presented demonstrating the importance of this kinase in regulating chemotaxis, in particular the directionality of chemotactic migration. Evidence suggesting that this kinase is important for phagocytosis, especially during engulfment and the internalization of large particles, is also reviewed. Finally, it is suggested that PI3K is important for superoxide production and neutrophil priming. The common link between these seemingly diverse functions is that PI3K(gamma), via its phospholipid products, appears to be providing spatial-temporal cues for the binding of actin-organizing proteins.

[Study on the surface hydroxyl species of diatomite using DRIFT spectroscopy]

Using DRIFT spectroscopy, we detected surface hydroxyl structure of diatomite in this study. There were either isolated hydroxyl groups or H-bonded hydroxyl groups on the surface of the diatomite. At room temperature, the diatomite surface was predominantly covered by weakly adsorbed water in cavity and water bonded to surface hydroxyl groups via H-bonds. There appeared a broad band with middle wavenumber at 3,400-3,500 cm-1 as a result in the corresponding DRIFT spectra. With driving off adsorbed water by heating the sample from 200 degrees C to 1000 degrees C, the broad band fade away gradually, and a single band at about 3,745 cm-1, which is attributed to both isolated hydroxyl groups and partial H-bonded hydroxyl groups, became more and more intense with increasing temperature. Under the heat treatment conditions of 1,100 degrees C for one hour, the isolated hydroxyl groups were mostly desorbed from the surface, and the H-bonded hydroxyl groups that existed above the inner wall of micropores with diameter of circa 10 nm, however, had not yet condensed thoroughly. The thermal behavior was supposed to be a speciality of diatomite.

Isolation and characterization of a new bacteriocin from Lactobacillus gasseri KT7

A bacteriocin-producing Lactobacillus gasseri strain, KT7, was isolated from infant faeces. The supernatant fluid showed inhibitory activity not only against some lactic acid bacteria but also, against some pathogenic and food-spoilage species, including Clostridium, Listeria and Enterococcus. An antimicrobial peptide designated gassericin KT7 was isolated from Lactobacillus gasseri KT7. It was purified to homogeneity by a single four-step procedure: a crude supernatant fluid obtained from early stationary-phase culture in MRS medium was subjected to ammonium sulphate fractionation, CM-Sephadex cation-exchange chromatography, Phenyl-Sepharose hydrophobic chromatography and reverse-phase HPLC chromatography. Gassericin KT7 was sensitive to proteolytic enzymes, resistant to heat, active over a wide range of pH, and migrated as a 4.5-5.0 kDa peptide on SDS-PAGE. The bacteriocin was produced constitutively during exponential growth. It was bactericidal to sensitive cells and the bactericidal effect was not produced by cell lysis. The amino acid composition of the bacteriocin was determined and no modified amino acid was found among the residues identified.

Activation of phospholipase C by the alpha subunits of the Gq and G11 proteins in transfected Cos-7 cells

High efficiency transient transfection was used to introduce cDNA corresponding to various G protein alpha subunits into Cos-7 cells. The proteins that were subsequently synthesized were detected with specific G protein alpha subunit antipeptide antiserum and were localized in the membrane fraction of the cell. Cells that were prelabeled with the [3H]inositol and transfected with G alpha q and G alpha 11 cDNA showed marked increases in formation of [3H]inositol phosphates after stimulation with aluminum fluoride. Co-transfection with cDNAs corresponding to phosphoinositide specific phospholipase C beta 1 (PI-PLC beta 1) and to G alpha q or G alpha 11 resulted in even higher levels of inositol phosphate formation. The introduction of mutations that convert residue glutamine 209 to leucine in G alpha q and G alpha 11 resulted in persistent activation of PI-PLC and high steady state levels of inositol phosphates. On the other hand, transfection with a variety of other G alpha subunit cDNAs, i.e. G alpha Z, G alpha OA, G alpha OB, transducin, and the glutamine 205 to leucine mutants of G alpha Z and of G alpha OA did not increase inositol phosphate formation. To further test the specificity of G protein activation of PI-PLC, a cell-free system was prepared by using washed membranes of transiently transfected cells and purified PI-PLC beta 1. Membranes derived from G alpha q and G alpha 11, but not G alpha OA transfected cells, showed guanosine 5-O-thiotriphosphate (GTP gamma S)-stimulated PIP2 hydrolysis. The activity seen in the system reconstituted with membranes derived from G alpha 11-transfected cells was blocked by preincubation with specific G alpha 11 antipeptide antibodies. All of these results are consistent with the conclusion that G alpha q and G alpha 11 cDNA encode proteins that in the presence of GTP gamma S specifically activate PI-PLC.

Characterization and molecular cloning of a putative binding protein for heparin-binding growth factors

A novel Mr 17,000 heparin-binding protein was purified from culture medium conditioned by A431 human epidermoid carcinoma cells. This protein, designated HBp17, was found to bind the heparin-binding peptide growth factors HBGF-1 and HBGF-2 in a noncovalent, reversible manner. In addition HBp17 was found to inhibit the biological activities of both HBGF-1 and HBGF-2. Both the binding and inactivation of HBGF-1 and HBGF-2 by HBp17 were abolished by heparin. Full-length 1163-base pair HBp17 cDNA was cloned and sequenced by using the polymerase chain reaction technique. The deduced primary structure of HBp17 consisted of 234 amino acids including each of five partial peptide sequences obtained from proteolytic fragments of purified HBp17. The encoded protein included a 33-residue N-terminal signal sequence for secretion and a single potential N-linked glycosylation site. No homology with any known protein was found for the deduced primary structure of HBp17. The expression of HBp17 mRNA was found to occur preferentially in normal human keratinocytes and in squamous cell carcinomas. This pattern of HBp17 gene expression suggests that this binding protein for HBGFs 1 and 2 has a physiological role in squamous epithelia.

Effect of ouabain on the relation between left ventricular oxygen consumption and systolic pressure-volume area (PVA) in dog heart

We studied the effect of ouabain (digitalis) on the relation between left ventricular (LV) O2 consumption (VO2) and pressure-volume (P-V) area (PVA) in 7 excised cross-circulated canine heart preparations. PVA is a measure of the total mechanical energy generated by LV contraction and was obtained as the specific area in the P-V diagram circumscribed by the end-systolic P-V line, end-diastolic P-V curve, and the systolic P-V trajectory. Ouabain (0.11 mg, intracoronary-arterially) increased Emax (LV contractility index) by 58 +/- 44% (mean +/- SD) from 7.8 +/- 3.4 to 12.0 +/- 4.8 mmHg/(ml/100 g LV). PVA correlated linearly with LV VO2 per beat in either the control (r greater than 0.97) or the ouabain run (r greater than 0.96) in individual hearts. Ouabain increased the VO2-axis intercept of the regression line of VO2 on PVA from 0.029 +/- 0.004 in the control run to 0.036 +/- 0.009 ml O2/beat/100 g LV without significantly changing the slope [(1.53 +/- 0.24).10(-5) ml O2/(mmHg/ml)] of the regression line. This slope is equivalent to the contractile efficiency value of 44 +/- 6% from the excess VO2 above unloaded VO2 to PVA. The parallel elevation of the VO2-PVA relation with ouabain was similar to the results produced by epinephrine and Ca2+ in our previous studies. Ouabain, like epinephrine and Ca2+, did not change the contractile efficiency from the PVA-dependent fraction of VO2 to PVA.