Hysteroscopic suture of levonorgestrel-releasing intrauterine system: learning curve for in vitro simulation training

OBJECTIVE

To simulate hysteroscopic suturing in vitro and analyze the learning curve of gynecologists with different experience levels.

METHODS

Three gynecologists were trained on uterine models in a circulating water box. The posterior uterine wall was sutured 10 times under hysteroscopy for 5 consecutive days, and the time of each suture procedure was recorded.

RESULTS

Doctors A, B, and C completed 50 posterior uterine sutures. After Dr. C completed 50 sutures on the posterior wall, he added 50 sutures on the anterior wall (Group D). The mean suturing time was 71.54 ± 68.158 s in Group A, 50.10 ± 28.060 s in Group B, 34.04 ± 10.457 s in Group C, and 30.38 ± 8.734 s in Group D. The difference between Groups C and B and between Groups B and A was statistically significant. There was no statistically significant difference between Groups C and D. Simulation curves were created using the number of features as the abscissa and cumulative sum as the coordinate, with peak curves of 19, 27, and 18 cases for Group A, B, and C, respectively.

CONCLUSION

Doctors with experience in single-hole laparoscopic surgery or hysteroscopic suture surgery can significantly shorten the hysteroscopic suturing time.

The effect of aminolevulinic acid hydrochloride topical powder photodynamic therapy versus nocardia rubra cell wall skeleton and observers group in the treatment of cervical low-grade squamous intraepithelial lesions with human papillomavirus infection: A non-randomized study, controlled pilot study

There are insufficient studies comparing the efficacy of aminolevulinic acid hydrochloride topical powder (ALA) photodynamic therapy (PDT) against Nocardia rubra cell wall skeleton (Nr-CWS) therapy in the treatment of cervical low-grade squamous intraepithelial lesion (LSIL) with human papillomavirus (HPV), especially for long-term efficacy. Patients with cervical LSIL and HPV infection were divided into 3 treatment groups based on their own choice. All patients had a follow-up test including HPV testing, cytology and colposcopy at 4 to 6 months and 12 months after the treatment. Among142 patients, patients received 51 ALA PDT and 41 patients received Nr-CWS. Another 50 patients who refused treatment were included in the Observers group. Four to six months or 12 months after treatment, there was significant difference between 3 groups in the clearance rate of HR-HPV infection and the complete remission (CR) rates of cervical LSIL; the CR rates of cervical LSIL in the ALA PDT group was significantly higher than the Nr-CWS group; but there was no significant difference between 2 groups in the clearance rate of HPV infection. The CR rates of cervical LSIL and the clearance rate of HPV infection in the ALA PDT group was significantly higher than the Observers group; the CR rates of cervical LSIL and the clearance rate of HPV infection in the Nr-CWS group was significantly higher than the Observers group; there was no significant difference in the recurrence rates in ALA PDT and Nr-CWS group after 12 months. Both of ALA PDT and Nr-CWS group had lower recurrence rate than the Observers group. The effect of ALA PDT is similar to Nr-CWS in the clearance rate of HR-HPV infection. Compared to the Nr-CWS group, the CR rates of cervical LSIL were considerably greater in the ALA PDT group. The effect of ALA PDT in the clearance rate of HPV infection and CR rates of cervical LSIL was significantly higher than the follow-up group; Both of ALA PDT and Nr-CWS group had lower recurrence rate than the Observers group. For cervical LSIL with HPV infection, ALA PDT is a very successful therapeutic method that is noninvasive.

Lower alanine aminotransferase levels are associated with increased all-cause and cardiovascular mortality in nonalcoholic fatty liver patients

BACKGROUND

Serum alanine aminotransferase (ALT) levels are often considered a marker to evaluate liver disease and its severity.

AIM

To investigate the association between ALT levels and all-cause and cause-specific mortality in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

The Third National Health and Nutrition Examination Survey (NHANES-III) from 1988 to 1994 and NHANES-III-related mortality data from 2019 onward were used to obtain the necessary data for the study. NAFLD was defined as hepatic steatosis, as diagnosed by ultrasound, with no other liver diseases. ALT levels were categorized into four groups according to the different recommended upper limits of normal (ULN) in men and women: < 0.5 ULN, 0.5-1 ULN, 1-2 ULN, and ≥ 2 ULN. The hazard ratios for all-cause mortality and cause-specific mortality were analyzed using the Cox proportional hazard model.

RESULTS

Multivariate logistic regression analysis demonstrated that the odds ratio of NAFLD correlated positively with increased serum ALT levels. In patients with NAFLD, all-cause mortality and cardiovascular mortality were the highest when ALT was < 0.5 ULN, yet cancer-related mortality was the highest when ALT was ≥ 2 ULN. The same results could be found in both men and women. Univariate analysis showed that severe NAFLD with normal ALT levels had the highest all-cause and cause-specific mortality, but the difference was not statistically significant after adjustment for age and multivariate factors.

CONCLUSION

The risk of NAFLD was positively correlated with ALT level, but all-cause and cardiovascular mortality were the highest when ALT was < 0.5 ULN. Regardless of the severity of NAFLD, normal or lower ALT levels were associated with higher mortality than elevated ALT levels. Clinicians should be aware that high ALT levels indicate liver injury, but low ALT levels are associated with a higher risk of death.

Hysteroscopic presentation of endometrial vascular dystrophy: a case report

Endometrial vascular dystrophy is quite rare, and there is very little literature regarding this subject. We present the unusual case of a 38-year-old woman who experienced vaginal bleeding after menstruation for 3 months. Hysteroscopically, the uterine cavity was filled with tiny, curved blood vessels, the bottom of the cavity was obvious, and polyps were visible. No curved vessels or polyps were identified after curettage. The diagnosis was endometrial hemodystrophy with endometrial polyps. Endometrial vascular dystrophy is a hysteroscopically uncommon benign lesion of the endometrial vessels.

Two Paths of Suture Fixation for Levonorgestrel-Releasing Intrauterine Devices Under Hysteroscopy

For patients with adenomyosis who are treated with a levonorgestrel-releasing intrauterine device (LNG-IUD), is there a better way to keep LNG-IUD from falling off? This paper introduced two ways to suture fixation of LNG-IUD under hysteroscopy. One way was to use the instrument channel in the hysteroscopic cold-knife surgery system (Zhu et al. in Fertil steril 116:1191-1193, 1), and the other way was to enter the uterine cavity from the side of the hysteroscope. A video description of the surgical procedure demonstrates the detailed technique. We sutured the LNG-IUD in two different ways as shown in the video. One method was to suture with a 3 mm needle holder through the operating channel; another option was to suture from the bypass. After the intrauterine suture, the suture needle was pulled out, and the middle part of the thread was tied to the top of the LNG-IUD. The knot was tied with a knot push device, and the hysteroscopy was performed again to determine the position of the knot and LNG-IUD, and the end of the suture was cut 1 cm from the knot. Case 1: A 42-year-old patient, gravida 4, para 2, underwent hysteroscopy 1 year ago due to adenomyosis. Postoperative pathology was endometrial hyperplasia. She was treated with LNG-IUD but unfortunately fell off twice due to cervical insufficiency. Case 2: A 47-year-old patient, gravida 3, para 2, was admitted to LNG-IUD 1 year ago because of adenomyosis, and the volume of menstruation decreased. The LNG-IUD fell off 3 months ago, and the LNG-IUD moved down after re-admission. LNG-IUD was successfully sutured and fixed in the intrauterine cavity in both patients within 30 min. The distending media of these two paths were 4000 ml and 6000 ml, respectively. The mean blood loss was about 5 ml for both patients, and they left the hospital after 2 h of observation. The menstrual volume of these two patients decreased, and the ultrasound showed that the LNG-IUD was in the right position at 1 and 3 months postoperatively. For patients with adenomyosis who have previously lost the LNG-IUD, these two methods of LNG-IUD fixation under hysteroscopy are both reliable to avoid the risk of the LNG-IUD being discharged again. The bypass method for LNG-IUD suture requires only an intrauterine laparoscope, which requires less instrumentation but higher suture skills.

A novel ent-pimarane-type diterpenoid from Sigesbeckia glabrescens with anti-inflammatory activity

A novel ent-pimarane-type diterpenoid, sigesbeckia J (1), along with two known diterpenoids, siegesbeckia acid (2) and ent-18-acetoxy-16R,17-dihydroxykauran-19-oic acid (3), were isolated from the aerial parts of Sigesbeckia glabrescens Makino. Their chemical structures were elucidated based on extensive spectroscopic interpretation. The absolute configuration of ent-pimarane-type diterpenoid (1) was determined by comparing experimental and calculated ECD spectra. Compared with the positive control minocycline (IC₅₀ 32.84 μM), compound 1 exhibited moderate cell growth anti-inflammatory activities in vitro by testing their inhibition of LPS-induced NO production in BV2 microglial cells, with IC₅₀ value of 58.74 μM.

Clinical practice guidelines for the nutritional risk screening and assessment of cancer patients: a systematic quality appraisal using the AGREE II instrument

PURPOSE

To evaluate the quality of published clinical practice guidelines (CPGs) regarding the nutritional risk screening and assessment of cancer patients and to identify high-quality CPGs for clinical healthcare professionals.

METHODS

Guidelines for the nutritional risk screening and assessment of cancer patients were comprehensively searched in eight electronic databases, including The Lancet, PubMed, Cochrane Library, Excerpta Medica dataBASE (EMBASE), Web of Science, China National Knowledge Infrastructure (CNKI), China Biology Medicine disc (CBMdisc), and Wan Fang Data, through August 2020. Six relevant guideline databases, including the National Comprehensive Cancer Network (NCCN), the National Guideline Clearinghouse (NGC), the Guideline International Network (GIN), the New Zealand Guidelines Group (NZGG), the China Guideline Clearinghouse (CGC), and Medlive, and relevant nutrition society websites, were also searched through August 2020. The methodological quality of the included CPGs was appraised independently by three assessors using the Appraisal of Guidelines for Research and Evaluation, 2nd edition (AGREE II) tool.

RESULTS

Seven CPGs were located, and the domain with the highest percentage was "clarity of presentation" (85.44%), while the domain with the lowest percentage was "applicability" (40.26%). From the AGREE II results, two guidelines were rated as "strongly recommended," three were assessed as "recommended with modifications," and two were deemed as "not recommended."

CONCLUSION

Considering that the two "strongly recommended" guidelines were developed within the American and European contexts, translation, validation, and cultural adaptation are recommended prior to implementing these guidelines in other countries or healthcare contexts to improve their effectiveness and sensitivity for local cancer patients.

TRIAL REGISTRATION

PROSPERO registration of the study protocol: CRD42020177390 (July 5, 2020).

Effect of maternal canthaxanthin and 25-hydroxycholecalciferol supplementation on the performance of ducklings under two different vitamin regimens

This study investigated the effects of maternal canthaxanthin (CX, 6 mg/kg) and 25-hydroxycholecalciferol (25-OH-D₃ , 0.069 mg/kg) supplementation on the performance of Cherry Valley ducklings under two different vitamin regimens. A total of 780 duck breeder females and 156 males were randomly allotted to two diets with or without the addition of the mixture of CX and 25-OH-D₃ (CX+25-OH-D₃ ) for 32 weeks. Ducklings (males and females separately) hatched from eggs laid at 24 weeks of the duck breeder trial were fed with a NRC vitamin regimen, and ducklings (males and females separately) hatched from eggs laid at 32 weeks of the duck breeder trial were fed with a HIGH vitamin regimen (had higher levels of all vitamins except biotin than NRC vitamin regimen), for 14 days. The results showed that, maternal CX+25-OH-D₃ supplementation increased the shank pigmentation for 7-days post hatch in ducklings under a NRC vitamin regimen, and for 14-days post hatch in ducklings under a HIGH vitamin regimen. Growth performance, antioxidant status and serum phosphorus of ducklings under a NRC vitamin regimen were increased by maternal CX+25-OH-D₃ supplementation; however, these positive effects were not observed in ducklings under a HIGH vitamin regimen. Males revealed increased growth performance in ducklings under both NRC and HIGH vitamin regimens. Sexual differences in shank pigmentation, antioxidant status, tibia strength and serum phosphorus were not consistent as they were dependent on maternal CX+25-OH-D₃ status or dietary vitamin regimens. Data suggest that maternal CX+25-OH-D₃ supplementation is important for starter ducklings under a NRC vitamin regimen, but not HIGH vitamin regimen.

Effects of dietary canthaxanthin and 25-hydroxycholecalciferol supplementation on the antioxidant status and tibia quality of duck breeders and newly hatched ducklings

This study evaluated the effects of dietary canthaxanthin (CX) and 25-hydroxycholecalciferol (25-OH-D3) supplementation on the antioxidant status and tibia quality of duck breeders and newly hatched ducklings. In total, 780 female and 156 male duck breeders were randomly allotted to 2 treatments. Duck breeders were fed either a commercial diet (containing 3,000 IU/kg vitamin D3) or the same diet plus a mixture of CX (6 mg/kg) and 25-OH-D3 (0.069 mg/kg) for 40 wk. The antioxidant status of duck breeders, egg yolk, and ducklings; tibia quality of duck breeders and ducklings; and shell quality of breeder eggs were investigated. The total antioxidant capacity of breeder female liver (P = 0.028), breeder male testis (P = 0.049), egg yolk (P = 0.032), one-day-old duckling liver (P = 0.024), and one-day-old duckling yolk sac (P = 0.012) were increased by dietary supplementation of the mixture of CX and 25-OH-D3 The inclusion of CX and 25-OH-D3 decreased liver protein carbonyl of breeder females (P = 0.030), and liver malonaldehyde (P = 0.050) and protein carbonyl (P = 0.030) of breeder males. Yolk (P < 0.001), shank (P < 0.001), and yolk sac pigmentation (P < 0.001) of one-day-old ducklings were increased by the supplementation of the CX and 25-OH-D3 mixture. No differences (P > 0.05) were observed in tibia quality or eggshell quality between treatments. In conclusion, the inclusion of the mixture of CX and 25-OH-D3 in a diet sufficient in vitamin D3 increased antioxidant status but not tibia quality of duck breeders and newly hatched ducklings.

Diets of differentially processed wheat alter ruminal fermentation parameters and microbial populations in beef cattle

The influences of differently processed wheat products on rumen fermentation, microbial populations, and serum biochemistry profiles in beef cattle were studied. Four ruminally cannulated Limousin × Luxi beef cattle (400 ± 10 kg) were used in the experiment with a 4 × 4 Latin square design. The experimental diets contained (on a DM basis) 60% corn silage as a forage source and 40% concentrate with 4 differently processed wheat products (extruded, pulverized, crushed, and rolled wheat). Concentrations of ruminal NH-N and microbial protein (MCP) in cattle fed crushed and rolled wheat were greater ( < 0.05) than the corresponding values in cattle fed pulverized and extruded wheat. Ruminal concentrations of total VFA and acetate and the ratio of acetate to propionate decreased ( < 0.05) with increased geometric mean particle size (geometric mean diameter) of processed wheat, except for extruded wheat; cattle fed extruded wheat had the lowest concentrations of total VFA and acetate among all treatments. The relative abundance of , , ciliated protozoa, and was lower in cattle fed the pulverized wheat diet than in the other 3 diets ( < 0.05), whereas the relative abundance of was decreased in cattle fed extruded wheat compared with cattle fed crushed and rolled wheat ( < 0.05). No treatment effect was obtained for serum enzyme activity and protein concentration ( > 0.05). Our findings suggest that the method of wheat processing could have a significant effect on ruminal fermentation parameters and microbial populations in beef cattle and that crushed and rolled processing is better in terms of ruminal NH-N and MCP content, acetate-to-propionate ratio, and relative abundance of rumen microorganisms.

SERS detection of R6G based on a novel graphene oxide/silver nanoparticles/silicon pyramid arrays structure

We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/silicon pyramid arrays structure (GO/Ag/PSi). The SERS behaviors are discussed and compared by the detection of R6G. Based on the contrast experiments with PSi, GO/PSi, Ag/PSi and GO/AgA/PSi as SERS substrate, the perfect bio-compatibility, good homogeneity and chemical stability were confirmed. We also calculated the electric field distributions using Finite-difference time-domain (FDTD) analysis to further understand the GO/Ag/PSi structure as a perfect SERS platform. These experimental and theoretical results imply that the GO/Ag/PSi with regular pyramids array is expected to be an effective substrate for label-free sensitive SERS detections in areas of medicine, food safety and biotechnology.

Toxicity of Mycotoxins from Contaminated Corn with or withoutYeast Cell Wall Adsorbent on Broiler Chickens

This study investigated the effects of feeds naturally contaminated with mycotoxins on growth performance, serum biochemical parameters, carcass traits, and splenic heat shock protein 70 (Hsp70) mRNA expression levels in broiler chickens. The efficacy of yeast cell wall (YCW) adsorbent in preventing mycotoxicosis was also evaluated. Three hundred 1-d-old Arbor Acres broiler chicks were randomly allotted to 3 treatments in completely randomized design for 42 d. Each treatment group had 5 replicate pens with 20 birds. The treatments were as follows: i) basal diet (control), ii) naturally contaminated diet (NCD), and iii) NCD+0.2% YCW adsorbent (NCDD). The NCD decreased average daily gain (ADG) (p<0.01) of 0 to 21 d, 22 to 42 d, and 0 to 42 d, and increased feed conversion ratio (p<0.01) of 22 to 42 d and 0 to 42 d. Both the breast meat percentage and thigh meat percentage of the NCD group were significantly higher (p<0.01) than that of the control group on d 21. The NCD group showed significantly increased levels of triglycerides (p<0.05) and cholesterol (p<0.05) on both d 21 and d 42 compared to the control group. However, the NCD significantly reduced (p<0.01) the high-density lipoprotein (HDL) on d 42 compared to controls. Compared with the NCD, supplementation with YCW significantly improved (p<0.01) the ADG of 0 to 21 d and 0 to 42 d, and increased (p<0.01) concentrations of HDL on d 42, and on d 21, and triglycerides (p<0.05) on d 21 and d 42. Supplementation with YCW reduced (p<0.01) the breast meat percentage, the thigh meat percentage, the concentrations of cholesterol (p<0.01) and the low-density lipoprotein (p<0.05) on d 21, and improved (p<0.01) the splenic Hsp70 mRNA expression levels compared with the NCD group. The results of this study indicated that feeding NCD for 42 d had adverse effects on broiler chickens, and that YCW might be beneficial in counteracting the effects of mycotoxins.

Zearalenone Altered the Serum Hormones, Morphologic and Apoptotic Measurements of Genital Organs in Post-weaning Gilts

The present study was aimed at investigating the adverse effects of dietary zearalenone (ZEA) (1.1 to 3.2 mg/kg diet) on serum hormones, morphologic and apoptotic measurements of genital organs in post-weaning gilts. A total of twenty gilts (Landrace×Yorkshire×Duroc) weaned at 21 d with an average body weight of 10.36±1.21 kg were used in the study. Gilts were fed a basal diet with an addition of 0, 1.1, 2.0, or 3.2 mg/kg purified ZEA for 18 d ad libitum. Results showed that 3.2 mg/kg ZEA challenged gilts decreased (p<0.05) the serum levels of luteinizing hormone, however, serum levels of prolactin in gilts fed the diet containing 2.0 mg/kg ZEA or more were increased (p<0.05) compared to those in the control. Linear effects on all tested serum hormones except progesterone were observed as dietary ZEA levels increased (p<0.05). Gilts fed ZEA-contaminated diet showed increase (p<0.05) in genital organs size, hyperplasia of submucosal smooth muscles in the corpus uteri in a dose-dependent manner. However, the decreased numbers of follicles in the cortex and apoptotic cells in the ovarian were observed in gilts treated with ZEA in a dose-dependent manner. Degeneration and structural abnormalities of genital organs tissues were also observed in the gilts fed diet containing 1.1 mg/kg ZEA or more. Results suggested that dietary ZEA at 1.1 to 3.2 mg/kg can induce endocrine disturbance and damage genital organs in post-weaning gilts.

Effects of naturally mycotoxin-contaminated corn on nutrient and energy utilization of ducks fed diets with or without Calibrin-A

One hundred sixty-two 21-d-old ducks were randomly allotted to 6 treatments with 3 levels of mycotoxin-contaminated corn (0, 50, and 100% M) and 2 levels of Calibrin-A (CA, a clay mycotoxin adsorbent, 0 and 0.1%) to evaluate the effects of increasing levels of mycotoxin-contaminated corn on nutrient utilization in ducks fed diets with or without CA. Endogenous losses were obtained from another 27 ducks. Excreta samples were collected to determine DM, OM, CP, amino acids, and gross energy. Gross energy was analyzed for computation of AME and TME. The apparent digestibility (AD) and true digestibility (TD) of the nutrients in all treatments with and without CA had common (P > 0.05) intercepts and slopes except Pro (P < 0.05). The AME, TME, AD, and TD of DM, OM, Phe, and Gly were linearly (P < 0.05) decreased as the concentration of contaminated corn in the diet increased. Ducks fed the 100% M diet supplemented with 0.1% CA increased AD and TD of Gly compared with the 100% M diet, and ducks fed 50 and 100% M diet supplemented with 0.1% CA increased AD and TD of Pro compared with 50% M and 100% M diet, respectively. In the present study, ducks fed mycotoxin-contaminated corn decreased nutrient digestibility in dose-dependent manner, and 0.1% CA supplementation improved AD and TD of Gly and Pro.

Sapphire-based graphene saturable absorber for long-time working femtosecond lasers

We report a long-time working femtosecond laser using metal-free sapphire-based graphene as a saturable absorber (SA). The sapphire-based graphene yielded excellent nonlinear saturable absorption properties and was demonstrated to be suitable as an SA for an ultrafast solid-state laser. Stable mode-locked pulses of 325 fs were obtained at a central wavelength of 1032 nm with a repetition rate of 66.3 MHz. At pump power of 8.23 W the average output power was 1.78 W and the highest pulse energy reached 26.8 nJ with a peak power of 72.6 kW. Our work opens up a facile route for making reliable graphene SA in the mode-locking technique and also displays an exciting prospect in making low-cost and ultrafast lasers.

Facile synthesis of graphene on dielectric surfaces using a two-temperature reactor CVD system

Direct deposition of graphene on a dielectric substrate is demonstrated using a chemical vapor deposition system with a two-temperature reactor. The two-temperature reactor is utilized to offer sufficient, well-proportioned floating Cu atoms and to provide a temperature gradient for facile synthesis of graphene on dielectric surfaces. The evaporated Cu atoms catalyze the reaction in the presented method. C atoms and Cu atoms respectively act as the nuclei for forming graphene film in the low-temperature zone and the zones close to the high-temperature zones. A uniform and high-quality graphene film is formed in an atmosphere of sufficient and well-proportioned floating Cu atoms. Raman spectroscopy, scanning electron microscopy and atomic force microscopy confirm the presence of uniform and high-quality graphene.

Toxicity of increasing aflatoxin B1 concentrations from contaminated corn with or without clay adsorbent supplementation in ducklings

A total of 1,280 1-d-old ducks were used in a study to investigate the effects of increasing aflatoxin B1 (AFB1) concentrations from naturally contaminated corn on young ducklings, and the effectiveness of a clay adsorbent (CA) to protect against those effects. Ducks were randomly allotted to 8 treatments (TRT) in a 4 × 2 factorial arrangement with 4 levels of AFB1 (0, 25, 50, and 100 μg/kg) and 2 levels of CA (0 and 0.1%) with 8 pens per TRT and 20 ducks per pen. All ducks were allowed ad libitum access to feed and water during the 21-d experiment. The ADG, ADFI, feed conversion rate, mortality, bill color, and CV of BW of each replicate were measured at the end of the study. Blood and tissue samples from 8 ducks per TRT were obtained on d 21 of the experiment to determine the serum immunoglobulin and protein concentrations, relative organ weights, and intestinal morphology. Average daily gain and relative weights of the liver, spleen, thymus, and bursa of Fabricius decreased linearly (P < 0.05) as dietary AFB1 increased. Serum proteins and intestinal villi heights and villus/crypt ratio followed the same pattern. Bill decolorization ratio, CV of BW, and mortality increased linearly (P < 0.05) as dietary AFB1 increased. Adding 0.1% CA to the diet improved (P < 0.05) the relative weights of the small intestine, spleen, and thymus, and the villus height and villus/crypt ratio of the duodenum and jejunum, as well as the serum IgG and IgM concentrations. Adding CA also reduced (P < 0.05) bill decolorization ratio, CV of BW, mortality, and serum IgA concentration. Therefore, duck performance was negatively affected by increasing AFB1 concentrations in diets. But the addition of 0.1% CA can protect against the detrimental effects caused by AFB1-contaminated corn in diets for ducks.

Effects of ginger root (Zingiber officinale) on laying performance and antioxidant status of laying hens and on dietary oxidation stability

To investigate the effects of ginger root (Zingiber officinale) on laying performance and antioxidant status of laying hens and on dietary oxidation stability, 675 Hy-Line brown laying hens at 27 wk of age were randomly allocated to 5 treatments with 5 replicates in a complete randomized design. Laying hens were fed corn-soybean meal based diets and supplemented with 0, 5, 10, 15, or 20 g of ginger powder/kg of diet for 10 wk. The ADFI, laying rate, average egg weight, egg mass, and feed conversion of each replicate were measured weekly. Blood samples from 10 laying hens and 15 egg samples/treatment were obtained on d 35 and 70 of the experiment to determine the serum or egg yolk antioxidant enzymatic activities. Three separate batches of each treatment diet were also made at the beginning of the experiment and stored at 20°C. Subsamples were taken at 10-d intervals to determine the dietary oxidation stability over a 60-d period. All laying hens had similar ADFI, laying rate, average egg weight, and feed conversion. However, laying hens supplemented with ginger powder had higher (P = 0.024) egg mass than the control group. Supplementation of ginger powder increased (P < 0.05) the serum and egg yolk antioxidant enzymatic activities of laying hens on d 35 and 70. Increasing ginger powder from 0 to 20 g/kg of diet linearly increased (P < 0.05) the peroxide value but linearly reduced (P < 0.05) the acid value of lipid extracted from stored diets for the first 30 d, but not for the second 30 d. Dietary supplementation of ginger powder improved laying performance and serum and egg yolk antioxidant status and enhanced dietary oxidation stability in a dose-dependent manner. The optimum supplementation rate of ginger powder in the diet of laying hens appeared to be between 10 and 15 g/kg of diet.

Effects of purified zearalenone on growth performance, organ size, serum metabolites, and oxidative stress in postweaning gilts

Zearalenone (ZEA), an estrogenic mycotoxin, is produced mainly by Fusarium fungi. Previous studies indicated that acute ZEA exposure induced oxidative stress and damage in multiple organs. Therefore, the present study was designed to investigate the adverse effects of dietary ZEA (1.1 to 3.2 mg/kg of diet) on oxidative stress and organ damage in postweaning gilts. A total of 20 gilts (Landrace × Yorkshire × Duroc) weaned at d 21 with an average BW of 10.36 ± 1.21 kg was used in the study. Gilts were housed in a temperature-controlled room, divided into 4 treatments, and fed a basal diet only (control) or basal diet supplemented with purified ZEA at a dietary concentration of 1 (ZEA1), 2 (ZEA2), or 3 (ZEA3) mg/kg of diet for 18 d ad libitum. The actual ZEA contents (analyzed) were 0, 1.1 ± 0.02, 2.0 ± 0.01, and 3.2 ± 0.02 mg/kg for control, ZEA1, ZEA2, and ZEA3, respectively. Gilts fed different amounts of dietary ZEA grew similarly with no difference (P > 0.05) in feed intake. Vulva size increased linearly over the 18 d of feeding in gilts fed diets containing 1.1 mg of ZEA/kg or greater (P < 0.001). Relative weight of genital organs, liver, and kidney increased linearly (P < 0.05) in a ZEA-dose-dependent manner. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, γ-glutamate transferase, urea, and creatinine (P < 0.05), and malondialdehyde concentrations in both serum and liver (P < 0.001) were also increased linearly in a ZEA-dose-dependent manner. However, spleen relative weight (P = 0.002) and activities of total superoxide dismutase and glutathione peroxidase (in both serum and liver (P < 0.05) were decreased linearly as dietary ZEA increased. Results showed that besides genital organs, the liver, kidney, and spleen may also be target tissues in young gilts fed diets containing 1.1 to 3.2 mg of ZEA/kg for 18 d. Increased key liver enzymes in the serum suggest progressive liver damage caused by feeding ZEA, and an increase in oxidative stress in gilts is another potential impact of ZEA toxicity in pigs.

T3098C and T53C mutations of HBV genotype C is associated with HBV infection progress

OBJECTIVE

To analyze the association between mutation(s) in preS region of HBV and hepatitis B disease progress in Chinese patients with genotype C chronic HBV infection.

METHODS

Ninety-three patients with chronic genotype C HBV infection, including 24 asymptomatic carriers (ASC), 26 patients with chronic hepatitis B (CHB), 22 patients with liver cirrhosis (LC) and 21 HCC patients were investigated. Levels of HBV DNA, HBeAg, alanine aminotransferase (ALT), asparate transaminase (AST) were measured. HBV preS region was analyzed by PCR direct sequencing.

RESULTS

The prevalence of preS T3098C and T53C mutations of genotype C HBV was significantly higher in LC and HCC patients than ASC and CHB patients. The rate of T3098C mutation in ASC, CHB, LC, and HCC patients were 0.00% (0/24), 3.85% (1/26), 9.09% (2/22), and 30.77% (8/22), respectively (P=0.0015), while the rate of T53C mutation was 12.50% (3/24), 3.85% (1/26), 40.91% (9/22), and 42.31% (11/26), respectively (P=0.0012).

CONCLUSION

The frequency of genotype C HBV preS T3098C and T53C mutations is associated with hepatitis B infection progression

Effects of ginger root (Zingiber officinale) processed to different particle sizes on growth performance, antioxidant status, and serum metabolites of broiler chickens

A study using 144 one-day-old Arbor Acres broilers was conducted to assess the effects of dried ginger root (Zingiber officinale) that was processed to particle sizes of 300, 149, 74, 37, and 8.4 microm on growth performance, antioxidant status, and serum metabolites of broiler chickens. The birds were housed in 24 wire cages in an environmentally controlled room. Dietary treatments were no supplementation (control) and supplementation with ginger root processed to 5 particle sizes at the level of 5 g/kg of diet. Average daily gain, ADFI, and feed conversion rate of chicks of each cage were measured weekly. Blood samples from 8 broilers per treatment were obtained at d 21 and 42 of the experiment to determine antioxidant enzymatic activities and metabolites in the serum, and the birds were subsequently killed to determine carcass yield and abdominal fat content. All broilers had similar ADFI or feed conversion rate over the entire experimental period. However, broilers supplemented with ginger powder tended to have higher ADG and had greater (P=0.014) carcass yield compared with that of the control. Supplementation of ginger increased (P<0.001) activities of total superoxide dismutase and glutathione peroxidase but reduced (P<0.01) concentrations of malondialdehyde and cholesterol in serum of broilers at 21 and 42 d of age. Concentration of total protein in serum of ginger-supplemented broilers tended (P=0.092) to be higher at 21 d and was higher (P=0.002) at 42 d of age compared with that of control broilers. Reducing particle size of ginger powder linearly reduced (P<0.05) cholesterol (d 21) and linearly increased (P<0.05) glutathione peroxidase (d 21), total superoxide dismutase (d 42), and total protein (d 21 and 42). Supplementation of ginger at the level of 5 g/kg improved antioxidant status of broilers and the efficacy was enhanced as the particle size was reduced from 300 to 37 microm.

Effect of repeated +Gz exposures on energy metabolism and some ion contents in brain tissues of rats

BACKGROUND

It has been demonstrated that during +Gz exposure cerebral blood flow is significantly reduced, resulting in brain ischemia. In pilots, such conditions could recur several times during centrifuge training and combat maneuvers and could possibly cause reversible change in brain energy metabolism.

HYPOTHESIS

In rats there is an association between +10 Gz exposure and the decreased brain metabolism, as indicated by decreased adenosine triphosphate (ATP) and ATPase activity, and increased adenosine diphosphate (ADP) and lactate, etc. The aim of the present study was to examine the time course and recovery of brain energy metabolism, lactate, ATPase activity, Na+, K+, Ca2+ and water contents after three +10 Gz exposures in rats.

METHODS

There were 64 male Sprague-Dawley rats that were restrained and placed on an animal centrifuge. They were divided into groups of 16. Control rats were exposed to +1 Gz and experimental rats were exposed to +10 Gz three times each for 3 min at 30-min intervals. After being euthanized, rat brains were removed 0 h, 1 h, or 6 h after the last centrifuge run. Brain samples were analyzed for energy metabolism, lactate, Na+-K+-ATPase activity, water and electrolytes contents.

RESULTS

The cortical ATP content, Na+-K+-ATPase and lactate dehydrogenase (LDH) activities decreased significantly, whereas the cortical ADP, adenosine monophosphate (AMP) and lactate contents increased significantly 0 h after three +10 Gz exposures, as compared with those of control. The ATP, ADP, and AMP contents returned to their control levels 1 h after the +10 Gz exposures, however, lactate content, Na+-K+-ATPase and LDH activities delayed recovery 6 h after +10 Gz exposures. The cortical K+ content increased significantly 0 h and 1 h after +10 Gz exposures, and returned to the control level 6 h after +Gz exposures. Na+ and water contents increased significantly 1 h and 6 h after the +10 Gz exposures. There was no significant change in Ca2+ content after +Gz exposures.

CONCLUSIONS

Three +10 Gz (3 min each) exposures were associated with transient depression of brain metabolism as indicated by a decrease in ATP, Na+-K+-ATPase activity, and an accumulation of lactate, and disturbance of ion homeostasis. It is suggested that a causal relationship might exist between repeated high +Gz exposures and brain metabolism.

[Human dynamic response to landing impact in selected body orientations]

Objective. To study changes of human dynamic response to landing impact in selected body orientations. Method. Five healthy young men were exposed to 10 G, 50 ms half-sine acceleration pulses. The angle included between human head-ilium axis and impact force direction was 30 degrees-70 degrees. The acceleration responses at head, shoulder, chest and ilium of the subjects were recorded along head-ilium and chest-back directions. Result. Within limits of the experiments, the minimum peak response at the head along head-ilium direction was 10.36 +/- 2.44 G at 50 degrees, and the maximum was 18.07 +/- 3.29 G at 70 degrees. The minimum peak response at the chest along head-ilium direction was 10.39 +/- 3.97 G at 70 degrees, and the maximum was 15.42 +/- 3.61 G at 60 degrees. The minimum peak response at the head along chest-back direction was 7.58 +/- 1.18 G at 30 degrees, and the maximum was 18.89 +/- 1.85 G at 70 degrees. The minimum peak response at the chest along chest-back direction was 7.21 +/- 1.99 G at 30 degrees, and the maximum was 17.67 +/- 2.16 G at 70 degrees. Conclusion. It was inferred that the best body orientation angle for landing impact might be 50 degrees.

[Changes of cerebral blood flow during 21 d head-down tilt bed rest and the effect of lower body negative pressure during the last week]

Objective. To investigate the changes of cerebral blood flow (CBF) during 21 d head-down tilt (HDT) bed rest and the effect of lower body negative pressure (LBNP) in the last week. Method. Twelve healthy male subjects were randomly divided into control and LBNP groups, with 6 in each group. All of them were exposed to -6 degrees HDT for 21 d. The LBNP group received -4.0 kPa LBNP training 1 h/d in the last week of HDT while the control group did not. CBF and cerebral vascular resistance were measured by rheoencephalogram in pre-HDT, day 3, 10 and 21 of HDT. Result. In control group, left cerebral I quadrant area and inrush velocity decreased significantly during HDT, and left cerebral delta Gy wave crest height decreased significantly, whereas left cerebral resistance index increased significantly on day 3 and 21 of HDT as compared to those of pre-HDT. In LBNP group, left cerebral I quadrant area decreased significantly, and left cerebral delta Gy wave crest height and inrush velocity tended to decrease on day 3 and 21 of HDT, whereas left cerebral resistance index increased significantly during HDT as compared to those of pre-HDT. There were no significant differences between above indexes in control group and LBNP group. Conclusion. It is suggested that 21 d HDT may increase cerebral vascular resistance and decrease CBF, which can not be prevented by LBNP training in the last week of 21 d HDT.

[Changes of cardiac function during 21 d head-down tilt bed rest and the effect of lower body negative pressure in the last week]

OBJECTIVE

To investigate the change of cardiac function during 21 d head-down tilt (HDT) bed rest and the effect of lower body negative pressure (LBNP) in the last week in human.

METHOD

12 healthy male served as subjects which were randomly divided into control and LBNP groups, with 6 in each group. All of them were exposed to -6 degrees HDT for 21 d. The LBNP group received -4.0 kPa LBNP training 1 h/d in the last week of the test. The cardiac pump function and cardiac systole function were measured before, during and after HDT.

RESULT

Cardiac output, cardiac index and stroke volume decreased significantly, whereas total peripheral resistance, pre-ejection period (PEP), isovolumetric contraction time/left ventricular ejection time (LVET) and PEP/LVET increased significantly during HDT in both control and LBNP groups, compared to pre-HDT values, and they returned to normal level on day 2 post HDT. PEP and PEP/LVET in LBNP group were significantly higher than those in control group on day 21 of HDT and day 2 post HDT.

CONCLUSION

The reduction of cardiac pump function and cardiac systole function induced by 21 d HDT could not be prevented by LBNP training in the last week of 21 d HDT.

Changes of human cerebral bottom arterial hemodynamics during 21 d head-down tilt (-6 degrees) bed-rest

OBJECTIVE

To investigate the change of human cerebral bottom arterial hemodynamics during 21 d simulated weightlessness.

METHOD

21 d -6 degrees head-down tilt bed rest (HDT) were used to simulate weightlessness. 6 healthy male, aged 24.8 +/- 6.1 served as subjects. Systolic blood velocity (Vs), diastolic blood velocity (Vd), mean blood velocity (Vm), pulsatility index (PI), resistance index (RI) and other indices of middle cerebral arteries (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA) were measured by transcranial ultrasound Doppler before HDT and on day 0 (D0), 1, 3, 7, 10, 21 of HDT. HUT +75 degrees 20 min orthostatic tolerance tests were done on day -1, 10, and 21 of HDT.

RESULT

During HUT +75 degrees 20 min orthostatic tolerance test on day 10 and 21 of HDT, the average standing time were shorter than that of the pre-HDT values (P<0.05). On day 3 and 21 of HDT, Vs of right MCA reduced significantly than pre-HDT (P<0.05 or P<0.01). On day 1, 3, 7, 10 and 21 of HDT, Vs of right MCA were obviously lower than that on D0 (P<0.05 or P<0.01). Left MCA Vs on D0 increased significantly than that of pre-HDT (P<0.05), and both were significantly higher than those of the 3rd day of HDT (P<0.01). Right MCA Vm on the 3rd and 21st day of HDT were significantly lower than those pre-HDT and D0 (P<0.05 or P<0.01). On day 10 of HDT, Vm of right MCA were significantly reduced than that on D0 (P<0.05). Both MCA bilateral velocity difference (right Vm-left Vm) on the 3rd, 10th, 21st day of HDT, and MCA inter-hemispheric asymmetry index on the 10th, 21st day of HDT were significantly lower than that of pre-HDT (P<0.05 or P<0.01).

CONCLUSION

21 d HDT bed-rest decreased orthostatic tolerance, Vs of both side MCA, and Vm of right MCA. Lower Vs of both side MCA and the inter-hemispheric asymmetry of MCA during HDT maybe responsible, in part, for the increased risk of orthostatic intolerance.

[The artificial liver's studies and progress]

This describes new achievements and progress in artificial liver studies.

[Effect of extremity cuffs as a countermeasure against the cardiovascular deconditioning during 21 d head-down bedrest]

OBJECTIVE

To affirm the protective effect of inflated cuffs.

METHOD

The protective effect against the cardiovascular deconditioning of inflated cuffs on the upper parts of thighs and arms during the 1st through 10th days of 21 d bedrest has been reported previously. The effect of the cuffs during the rest of the 21 d bedrest were studied in this paper. Five subjects in cuffs group whose orthostatic tolerance were well maintained continued bed rest for 7 d without inflated cuffs. For the last 4 days of this period, inflated cuffs were again applied. Orthostatic tolerance of subjects in cuffs group with and without cuffs were measured.

RESULT

Two of the five subjects suffered orthostatic intolerance on the 17th day. No sign of orthostatic intolerance were observed by the end of bedrest.

CONCLUSION

(1) the cardiovascular deconditioning developed when inflated cuffs were not used, and (2) the use of inflated cuffs for 4 d improves the orthostatic tolerance.

[Variation of several volume regulating hormones during 21 d - 6 degrees head-down bed rest]

Objective To investigate variations of plasma renin activity, a prostaglandin I2 (PGI2) during 21 d -6 degrees head-down tilt (HDT) with and without lower body negative pressure (LBNP).

METHOD

-6 degrees head-down tilt for 21 d were used to simulate weightlessness. 12 healthy male, aged 23.7 +/- 5.0, were equally and randomly divided into control group (CON) and LBNP group. The latter subjected to LBNP (-30 mm Hg, 1 h/d) in the last week of HDT. Samples of plasma were taken before HDT and on the 2nd, 4th, 11th and 22nd day during HDT.

RESULT

Compare to control levels, Ald declined significantly on the 2nd (CON -30%, P < 0. 05; V. S. LBNP -38%, P < 0.01), and increased significantly on the 11th day (CON +30%, P < 0.05; LBNP +48%, P < 0.01). PRA reached peak value on the 4th day (P < 0.05), and declined to below the control level on the 22nd day. PGI2 increased constantly during HDT, and increased significantly on the 22nd day (CON P < 0.01), 11th, 22nd (LBNP P < 0.05). No apparent difference was found between groups after LBNP concerning PRA and Ald; and PGI2 didn't increase further in LBNP group. Conclusion HDT induced a timely increasing in PRA and Ald, constant increasing in PGI2.

[Countermeasuring effect of lower body negative pressure against orthostatic intolerance induced by 21 d -6 degrees head down tilt in humans]

Objective. To investigate whether LBNP during 21 d -6 degrees head-down tilt (HDT) would modify orthostatic tolerance. Method. 12 healthy males, age 23.7 +/- 5.0, were exposed to -6 degrees HDT for 21 d. 6 of them received -4.0 kPa LBNP sessions for 1 h/d from 15th day to 21st day of HDT. The other 6 served as control. HUT + 75 degrees, 20 min orthostatic tolerance test were done before, on day 10 and on day 21 of HDT. Result. During HUT + 75 degrees, 20 min orthostatic tolerance test on day 10 of HDT, 5 subjects of the control group and 4 of the LBNP group presented presyncopal or syncopal signs and symptoms, the average standing time of both groups were shorter than those of the pre-HDT (p<0.05). During HUT + 75 degrees, 20 min orthostatic tolerance test on day 21 of HDT, 5 subjects of the control group and one subject of the LBNP group presented presyncopal or syncopal signs and symptoms, the average standing time of control group reduced significantly as compared with those of pre-HDT(P<0.05), also significantly shorter than those of LBNP group (P<0.05). Conclusion. The present study clearly shows that the use of LBNP could alleviate the bed rest-induced orthostatic intolerance.

Preparation and characterization of the monoclonal antibodies against Japanese encephalitis virus

Six mouse monoclonal antibodies (MoAbs) against Japanese encephalitis virus (JEV) were prepared and analyzed with indirect immunofluorescence assay (IFA), enzyme linked immunosorbent assay (ELISA), haemagglutination inhibition test (HI), neutralization test (NT), antibody dependent cell mediated cytotoxicity (ADCC) assay, antigenic site specific analysis and relative affinity measurement. These MoAbs could be divided into three classes by indirect immunofluorescence cross reactivity among four flaviviruses, 2H4, 2F2, and nG2 were type specific; 2D2 and mC3 were subgroup specific; and mG9 was family specific. 2H4 and 2F2 had higher neutralization activity, 2D2 and mC3 had the function of inducing ADCC effect, mG9 had higher titer in HI. The six MoAbs recognized five antigenic sites on JEV envelope glycoprotein, 2H4 and 2F2 recognized the same or very similar antigenic site and their relative affinity was ranked as: nG2 > 2H4 > 2D2 > mG9 > 2F2 > mC3.

Identification and characterization of a 30K glycoprotein of herpes simplex virus type 2

A herpes simplex virus type 2 (HSV-2) type-specific monoclonal antibody (MAb), CH-A9, precipitated a glycoprotein with an M(r) of approximately 30,000 (g30K) from extracts of HSV-2-infected BHK cells labelled with [3H]leucine, [14C]fructose or [3H]glucosamine. The M(r) of this glycoprotein is lower than those of other HSV glycoproteins. Immunoassays of BHK cells infected with HSV-1-HSV-2 intertypic recombinants localized the gene encoding the target antigen of MAb CH-A9 to the unique long (UL) region at map units 0.490 to 0.564. Tunicamycin effectively inhibits N-linked glycosylation of g30K, which suggests that g30K may be modified by addition of N-linked oligosaccharides and that the amino acid sequence may contain Asn-X-Ser or Asn-X-Thr. The g30K was also purified on an immunoadsorbent column consisting of MAb CH-A9 linked to Sepharose 4B and was shown to be an HSV-2 type-specific antigen by indirect ELISA. The glycoprotein could induce HSV-2 type-specific neutralizing antibody in BALB/c mice. This evidence suggests that g30K may be a novel glycoprotein of HSV-2.

Effects of hyperthermia and/or hyperglycemia on pH and pO2 in well oxygenated xenotransplanted human sarcoma

The heat-induced interdependent changes of tumor blood flow, pO2, and pH decisively influence the therapeutic effect of hyperthermia (HT). This fact has induced us to determine simultaneously the frequency distribution of local pO2 values and the intratumoral pH in a xenotransplanted human sarcoma cell line at a normal blood glucose level and under hyperglycemic conditions before, during, and after HT. Two groups, one of 10 and one of 9 congenitally athymic nude rats with a subcutaneously implanted S117 human sarcoma into the right hind paw (mean tumor volume 5.3 cm3) were treated with local waterbath HT (tumor temperature 43 degrees C, 1 hr) alone or in combination with i.p. glucose injections (6 g/kg, 2 hr before the onset of HT). Tumor oxygenation remained improved throughout HT. Tumor pH did not decrease during HT. Hyperglycemia alone elicited a decrease of intratumoral pH and pO2, probably mainly due to hemoconcentration. The additional warming of the tumors (43 degrees C) during hyperglycaemia did not further decrease pO2 and pH. Silver stained sections of the tumors showed only a few very small necrotic areas, even in tumors of volumes up to 8 cm3. Our results indicate a well oxygenated tumor. In contrast to most tumors studied so far, hyperthermia in this tumor induces not only an initial increase of oxygenation but a lasting elevation of mean tumor pO2 for the duration of HT (up to 60 min).

Passive protection of mice, goats, and monkeys against Japanese encephalitis with monoclonal antibodies

Six monoclonal antibodies (McAbs) against Japanese encephalitis virus (JEV) were tested for passive protection in JEV-infected mice, goats, and rhesus monkeys. mG9 and nG2 had no protective effect; mG3 and 2D2 had some protective effect, but not sufficient to be of therapeutic significance; and 2H4 and 2F2 had excellent protective efficacy in mice even 120 hr after infection when most of the mice in the virus control group were sick. The mixture of 2H4, 2F2, mC3 (M-McAb), and their F(ab')2 fragments showed excellent protection in mice, goats, and monkeys and was safe. The protective effects of McAbs correlated with their neutralization titers, but cytotoxicity-mediated activities also played a role in protection.

Multistage evaluation scale, differential threshold steps and equivalent sensation contours of respiratory flow-resistive load sensation

This paper presents and discusses the methodology and results of studies on respiratory sensation by using a fuzzy set category judgement model and applying the concept of just noticeable difference (JND) step and equivalent sensation. A new kind of category scale, the multistage evaluation scale (MES), based on a fuzzy set category judgement model for quantifying respiratory sensory magnitude has been put forward and verified in 37 subjects. The perceived magnitude of added resistance estimated using MES could reflect properly the difference in sensory perception caused by added loads with equal intensity but applied to different phases of the breathing cycle. In addition, the psychophysical function obtained conforms to the Stevens' power law. On the contrary, the classical category scale does not possess some of these attributes. In 9 subjects, we determined that the sensory continuum corresponding to either inspiratory or expiratory added resistive load, ranging 10-500 mm H2O.1(-1).s, consisted of 6 or 7 JND steps. The sensory magnitude corresponding to each step was estimated by the MES. Relating the results of JND step measurements with that of magnitude estimation using MES, we could elucidate systematically the relationship between perceived magnitude and discrimination for respiratory sensation. In 13 subjects, the equivalent respiratory resistive load sensation contours of 2, 3 and 4 JND step above basal level, respectively, were obtained through experimentation and by quadratic polynomial approximation of experimental data. The results suggest that as regards the human tolerance to various added resistive loads the combined resistive load is the most tolerable among the three; the expiratory, the least. The equivalent sensation contour can be used to predict the changes in respiratory sensation determined by both the intensity of the total added load and the ratio of inspiratory versus expiratory load. In brief, we have proposed a new way to elucidate the physiological and psychophysical effects of various added resistive loads.