Biomedical subjects

Yu Chang

Publications and source records attributed to Yu Chang.

27 records · Page 2Linked to original sources

PubMed2003

An unexpected quadruplet heterotopic pregnancy after bilateral salpingectomy and replacement of three embryos.

OBJECTIVE: To report a case of combined intrauterine and interstitial twin pregnancies after bilateral salpingectomy and IVF with replacement of three embryos. DESIGN: Case report. SETTING: University hospital. PATIENT(S): A 31-year-old woman known to have bilateral salpingectomy for ectopic pregnancies who underwent IVF. INTERVENTION(S): Laparotomy. MAIN OUTCOME MEASURE(S): Postoperation intrauterine monozygotic twins survival and birth. RESULT(S): After removing the interstitial monozygotic twin pregnancy, the patient had an uneventful postoperative course and delivered two healthy girls by cesarean section at 38 weeks' gestation. CONCLUSION(S): Heterotopic pregnancy can still occur in women treated by IVF after bilateral salpingectomy. The early sonography follow-up of IVF pregnancy would be of value because of the reported higher incidence of pathological pregnancies and especially monozygotic twinning.

Adult↗

PubMed2003

Multilobular cyst as endosalpingiosis of uterine serosa: a case report.

A case of endosalpingiosis presented as a multilobular cyst on sonography. The tentative clinical diagnosis was an ovarian tumor; however, laparotomy revealed a degenerative cyst of the uterine myoma with a stalk connecting to the uterus. Histopathologically, it showed characteristics of endosalpingiosis. To our knowledge, such a multilobular cyst of endosalpingiosis originating solely from the uterine serosa has not been reported.

Cysts↗

PubMed2003

Detecting forest landscape boundary between mountain birch and evergreen coniferous forest in the northern slope of Changbai Mountain.

Boundaries between different forest types in Changbai Mountain Eastern China are results from complex interactions between forest ecosystems, topography, and geomorphology. Detecting and quantifying the transitional zones are highly important since high environmental heterogeneity and biodiversity are often found within these zones. In this study, we used GIS and multivariate statistics techniques (PCA and MSWA) to analyze data from Landsat TM satellite imageries and quantitatively determined the positions and widths of the landscape boundary between mountain birch and evergreen coniferous forests in the northern slope of Changbai Mountain. The results showed that the widths of the landscape boundary ranges from 30-50 m while using the MSWA or/and PC method. Such detected widths are consistent with field transect data that suggests a 50 m transitional zone width. The results further suggest that TM data can be used in combination with GIS and statistical techniques in determining forest landscape boundaries; MSWA is more reliable than PCA, while PCA can also be used to determine the landscape boundary when transects are properly located.

Altitude↗

PubMed2003

[GIS and RS determination of abiotic range of forest landscape distribution in Changbai Mountain Natural Reserve].

Based on landscape classification of remote sensing data and spatial expression of environmental factors, the abiotic ranges of forest landscape distribution in Changbai Mountain Natural Reserve were determined by using GIS. The results showed that the optimum elevation range of tundra, mountain birch forest, evergreen coniferous forest, and broad-leaved Korean pine forest were 1780-2212 m, 1705-1956 m, 1042-1625 m, and 823-1184 m, respectively. The corresponding optimum annual average temperature ranges were -4.75(-)-2.40 degrees C, -3.42(-)-2.07 degrees C, -1.49-1.39 degrees C, and 0.71-2.37 degrees C, and the optimum ranges of annual precipitation were 1034-1110 mm, 1014-1060 mm, 883-1017 mm, and 824-925 mm, respectively. The forest landscapes in Changbai Mountain Natural Reserve were mainly distributed in flat and gentle areas. This distribution pattern was closely related to aspect. Tundra was almost evenly present in various aspects. In northern and northwestern direction, most forest landscapes were distributed, including mountain birch forest, evergreen coniferous forest, broad-leaved Korean pine forest, aspen and Betula forest. Most larch forest was in favor of northeastern direction with small amount facing eastern and northern way. Sparse forest briefly occupied west aspect with some orienting in southwest, northwest and south, while all wind-thrown areas were facing west, southwest and northwest aspects.

Conservation of Natural Resources↗

PubMed2003

[Scaling effects on landscape pattern indices].

The methods of spatial data aggregation based on majority and random rules were used in this study to reveal the scaling effects on landscape pattern in a classified TM imagery with 8 land cover types. For the majority rule-based aggregations, the proportion of most common cover types increased slowly, while that of less common cover types decreased rapidly with increasing grain. For random rule-based aggregation, each cover remained its original area on the aggregated maps. The largest patch sizes of shrub decreased, and those of the others increased in the majority rule-based aggregations with increasing scales. For random rule, the largest patch size of water (smallest cover type) decreased, but that of the others increased. The smallest patch size of each cover type was equal to the square of grain sizes. The average patch size of each cover type increased with increasing scales. However, the average patch size of dominant cover types increased rapidly in majority rule-based aggregations, while that of less common cover types increased rapidly in random rule-based aggregation. The patch count of each cover types decreased substantially with increasing grain. Random rule-based aggregation made landscape more fragmented and remained more patches. The diversity decreased in majority rule-based aggregation, and maintained its original value in random rule-based aggregation with increasing scales. Aggregation indices decreased with increasing map and measurement resolution, and the landscape became more aggregated in majority rule-based aggregation. However, under fixed measurement resolution (e.g., 30 m), aggregation indices increased and cover types were more clustered with increasing resolution. Moran's I decreased rapidly with increasing measurement and map resolution, and each cover type tended to be arranged randomly and independently in space. However, under fixed measurement resolution (e.g., 30 m), Moran's I increased and cover types were more clustered on aggregated maps than on original map with increasing map resolution.

Ecosystem↗

PubMed2002

[Comparative study of tissue cultured Dendrobium protocorm with natural Dendrobium candidum on immunological function].

OBJECTIVE: To compare the immunological function and acute toxicity of the tissue cultured protocorm from Dendrobium candidum with natural medicinal materials from Dendrobium candidum. METHODS: The effect on immunological function was examined by counting white blood cells, weighing the weight of immune organs, and using carbon granules clearance and lymphocyte transformation test in mice treated with cyclophospamide. The acute toxicity was studied by giving maximum tolerated dose. RESULTS: The tissue cultured protocorm could increase the quantity of white blood cells, the ratios of thymus weight to body weight and spleen weight to body weight, promote the function of phagocytes and enhance the lymphocyte transformation rate. The mice could tolerate the dose of 54.56 g/kg(dried herbs) by oral administration. The functions were similar to those of natural medicinal materials from Dendrobium candidum. CONCLUSION: Both tissue cultured protocorm and natural medicinal materials from Dendrobium candidum could improve immunological function with similar potency. The maximum tolerated dose was 227 times as high as the effective clinical.

Adjuvants, Immunologic↗

PubMedDate not supplied

Chronic administration of atrial natriuretic peptide reduces testosterone production of testes in mice.

The purpose of the present study was to examine the effect of the long-term administration of human atrial natriuretic peptide (ANP) on testosterone production in male mice. Twenty-five mice received ANP (20 ng/hour/g body weight) for 7 days via mini-osmotic pump, and the other group (n = 25) received twice-daily intraperitoneal injections. After death, levels of follicle-stimulating hormone, luteinizing hormone (LH), and testosterone in plasma, pituitary gland, and testis were measured by radioimmunoassay. Five mice from each group were examined histologically. In the minipump group, pituitary and plasma levels were significantly higher than those in the control group (771.2 +/- 43.6 vs 644.8 +/- 24.9 ng/mg and 6.7 +/- 0.6 ng/mg vs 2.5 +/- 0.6 ng/mL, respectively). In the intraperitoneal group, plasma LH levels were significantly higher in the ANP-treated group than that in control mice (9.6 +/- 0.3 ng/mg vs 3.8 +/- 0.5 ng/mL), whereas pituitary levels did not differ significantly. In both studies, testicular and plasma testosterone levels were significantly lower than those in control mice (P <.02). Histological features of the testes in ANP-treated mice revealed structural disorganization and inhibition of spermatogenesis. We conclude that the chronic administration of ANP may result in reduced testosterone production due to testicular damage.

Animals↗

PubMedDate not supplied

A randomized comparison of vesicourethral function after laparoscopic hysterectomy with and without vaginal cuff suspension.

STUDY OBJECTIVE: To compare vesicourethral function following laparoscopic hysterectomy (LH) with and without vaginal cuff suspension. DESIGN: Prospective study (Canadian Task Force classification I). SETTING: Tertiary teaching hospital. PATIENTS: Sixty-eight women scheduled for LH randomly assigned to either LH without vaginal cuff suspension (LH group; n = 36) or LH with suspension (LHS group; n = 32). INTERVENTION: All subjects received urinalysis, pelvic examination, Q-tip test, introital ultrasonography, and a urinary questionnaire before and 6 months after surgery. MEASUREMENTS AND MAIN RESULTS: The prevalence of stress urinary incontinence (SUI) decreased significantly from 46.9% (n = 15) preoperatively to 18.8% (n = 6) postoperatively in the LHS group (p = .022), but this was not so in the LH group. Similarly, the mean straining urethral angle and the number of women exhibiting bladder neck (BN) hypermobility significantly decreased after surgery in only the LHS group (p <.05; p <.01, respectively). During straining, the postoperative position of the BN localized more dorsally (p <.01), and its ventral mobility decreased significantly (p <.01) in the LH group. In the LHS group, significant postoperative reduction was found in both ventral and caudal movements of the BN during stress (p <.01), causing a more cranial and dorsal position of the BN (p <.01). CONCLUSION: Laparoscopic hysterectomy with cuff suspension strengthens the traction effect on the endopelvic fascia, reducing both BN mobility during stress and the chance of SUI. However, simply performing a cuff suspension is not adequate for the treatment of severe SUI.

Adult↗

PubMedDate not supplied

A modified method of laparoscopic presacral neurectomy for the treatment of midline dysmenorrhea.

STUDY OBJECTIVE: To describe the modified surgical technique of laparoscopic presacral neurectomy. DESIGN: A prospective trial (Canadian Task Force classification II-1). SETTING: University hospital. PATIENTS: Forty-two women with severe midline dysmenorrhea. INTERVENTION: Laparoscopic modified presacral neurectomy (LMPSN). MEASUREMENTS AND MAIN RESULTS: We designed a prospective study and used a zero-to-10 pain score system to evaluate 42 patients before and after LMPSN. Before surgery, each patient had pain scores ranging from 7 to 10 and had failed medical management. Mean time required to perform LMPSN was 7.33 +/- 1.76 minutes, and most women were discharged the day after surgery. The mean postoperative pain score of 2.02 +/- 2.25 was obtained 6 months after surgery and again at 12 months. No patient had intraoperative or long-term complications. CONCLUSION: When a patient requires surgical treatment for chronic midline pelvic pain or severe dysmenorrhea, LMPSN is an alternative choice. It is relatively safe, simple to perform, and satisfactory. This modified surgical procedure appears to increasingly succeed in treatment of midline dysmenorrhea.

Adult↗