[A prospective study on association between sleep duration and the risk of chronic obstructive pulmonary disease in adults in Suzhou].

Objective: To investigate the prospective association of sleep duration with the development of chronic obstructive pulmonary disease (COPD) in adults in Suzhou. Methods: The study used the data of 53 269 participants aged 30-79 years recruited in the baseline survey from 2004 to 2008 and the follow-up until December 31, 2017 of China Kadoorie Biobank (CKB) conducted in Wuzhong District, Suzhou. After excluding participants with airflow limitation, self-reported chronic bronchitis/emphysema/coronary heart disease history at the baseline survey and abnormal or incomplete data, a total of 45 336 participants were included in the final analysis. The association between daily sleep duration and the risk for developing COPD was analyzed by using a Cox proportional hazard regression model, and the hazard ratio (HR) values and their 95%CI were calculated. The analysis was stratified by age, gender and lifestyle factors, and cross-analysis was conducted according to smoking status and daily sleep duration. Results: The median follow-up time was 11.12 years, with a total of 515 COPD diagnoses in the follow-up. After adjusting for potential confounders, multifactorial Cox proportional hazard regression analysis showed that daily sleep duration ≥10 hours was associated with higher risk for developing COPD (HR=1.42, 95%CI: 1.03-1.97). The cross analysis showed that excessive daily sleep duration increased the risk for COPD in smokers (HR=2.49, 95%CI: 1.35-4.59, interaction P<0.001). Conclusion: Longer daily sleep duration (≥10 hours) might increase the risk for COPD in adults in Suzhou, especially in smokers.

Strategies for patients with recurrent nasopharyngeal carcinoma involved internal carotid artery who are intolerant to embolization.

BACKGROUND: The surgical treatment of recurrent nasopharyngeal carcinoma (rNPC) involving the internal carotid artery (ICA) is challenging, as the massive bleeding caused by intraoperative rupture of the ICA is life-threatening. We reported that ICA embolization is an effective pretreatment to avoid fatal bleeding, but some patients cannot tolerate the procedure. We used endovascular vascular protection (ICA stents), vascular sacrifice (bypass grafting) and extravascular vascular protection (transcervical external stent placement) of the ICA to provide alternative options for these patients. METHODOLOGYy: This study enrolled patients with rNPC adjacent to or invading the ICA who were unsuitable for ICA embolization from January 2015 to June 2020. ICA pretreatment combined with endoscopic nasopharyngectomy (ENPG) was performed for the 30 patients. We report the survival outcome and incidence of complications after ICA pretreatment. RESULTS: ICA pretreatment was performed for the 30 enrolled patients, among whom 8 underwent endoscopic-assisted transcervical protection of the parapharyngeal ICA combined with ENPG, 6 underwent bypass grafting, and 16 underwent ICA stent implantation followed by ENPG. After pretreatment, at a median follow-up of 43 months (range, 2-80 months), the 3-year locoregional overall survival (OS), progression-free survival (PFS), locoregional recurrence-free survival (LRRFS), and distant metastasis-free survival (DMFS) were 62.9%, 61.3%, 70.2%, and 71.4%, respectively. CONCLUSIONS: ICA pretreatment combined with salvage ENPG enables the feasible and effective resection of rNPC lesions involving the ICA in patients who cannot tolerate ICA embolization. Therefore, this treatment may be an effective method for improving outcomes. Multidisciplinary therapy is needed to reduce operation-related complications.

[Three-dimensional finite element study on the effects of maxillary anterior two-step retraction and en-masse retraction with clear aligners].

Objective: To investigate the effects of two-step retraction and en-masse retraction on tooth movement pattern of anterior teeth and posterior anchorage with clear aligners using three-dimensional finite element analysis. Methods: A finite element model of maxillary first premolar extraction case undergoing clear aligner treatment was established based on maxillofacial cone-beam CT data of a 24-year-old adult male with individual normal occlusion, who visited Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine for impacted mandibular third molar in June, 2022. The initial tooth displacement of five anterior retraction protocols (two-step with canine retraction, two-step with incisor bodily retraction, two-step with incisor retraction-overtreatment, en-masse bodily retraction, and en-masse retraction-overtreatment) were evaluated. Results: Two step with canine retraction caused distal tipping of the canine and labial tipping of the incisors (0.18° for central incisor and 0.13° for lateral incisor). Two step with incisor retraction caused mesial tipping of the canine. In two step with bodily retraction protocol, uncontrolled lingual tipping was found in central incisor (0.29°) and lateral incisor (0.32°). In two-step with incisor retraction-overtreatment protocol, the movement pattern of the incisors didn't change, but the inclinations reduced to 0.21° and 0.18°. En-masse retraction caused distal tipping of the canine. In en-masse bodily retraction protocol, uncontrolled lingual tipping was also found in central incisor (0.19°) and lateral incisor (0.27°). In en-masse retraction-overtreatment protocol, the central incisor showed controlled lingual tipping (0.02°) and the lateral incisor showed palatal root movement (0.03° labial inclination). Posterior teeth exhibited mesial tipping in all five protocols. Conclusion: En-masse retraction with incisor overtreatment was beneficial to incisor torque control in clear aligner treatment.

[Incidence of chronic obstructive pulmonary disease and risk factors in the Suzhou cohort].

Objective: To understand the incidence of chronic obstructive pulmonary disease (COPD) in the Suzhou cohort, and explore the risk factors for the development of COPD in Suzhou, and provide a scientific basis for COPD prevention. Methods: This study was based on the China Kadoorie Biobank project in Wuzhong District, Suzhou. After excluding individuals with airflow obstruction and self-reported chronic bronchitis, emphysema, or pulmonary heart disease at baseline, 45 484 individuals were finally included in the analysis. Cox proportional risk models were used to analyze risk factors of COPD and calculate hazard ratios and 95% confidence interval (CI) in the Suzhou cohort. The effect modifications of smoking on the association between other risk factors and COPD were evaluated. Results: Complete follow-up was available through December 31, 2017. Participants were followed up for a median of 11.12 years, and 524 individuals were diagnosed with COPD during the follow-up period; the incidence was 105.54 per 100 000 person-years. Multivariate Cox proportional risk regression models showed that age (HR=3.78, 95%CI:3.32-4.30), former smoking (HR=2.00, 95%CI:1.24-3.22), current smoking (<10 cigarettes/day, HR=2.14, 95%CI:1.36-3.35;≥10 cigarettes/day, HR=2.69, 95%CI:1.60-4.54), history of respiratory disease (HR=2.08, 95%CI:1.33-3.26), daily sleep duration ≥10 hours (HR=1.41, 95%CI:1.02-1.95) were associated with increased risk of COPD. However, education level of primary school and above (primary or junior high school, HR=0.65, 95%CI:0.52-0.81; high school and above, HR=0.54, 95%CI:0.33-0.87), consuming fresh fruit daily (HR=0.59, 95%CI:0.42-0.83) and consuming spicy food weekly (HR=0.71, 95%CI:0.53-0.94) were associated with reduced risk of COPD. Conclusions: The incidence of COPD is low in Suzhou. Older age, smoking, history of respiratory disease, and long sleep duration were risk factors for the development of COPD in the Suzhou cohort.

Stent pretreatment for internal carotid artery exposed to necrotic lesions in nasopharyngeal carcinoma.

BACKGROUND: Post radiation nasopharyngeal necrosis (PRNN) invading the internal carotid artery (ICA) contributes to the death of 69.2-72.7% of PRNN patients. ICA occlusion is an effective treatment to avoid fatal bleeding, while some patients are intolerant. We present a novel method that allows for these patients without interrupting blood flow through the ICA. METHODOLOGY: This study enrolled patients with PRNN-invaded ICA who were not suitable for ICA occlusion from April 2020 to November 2022. ICA stent pretreatment was performed in the 36 patients and followed the endoscopic nasopharyngectomy (ENPG) or conservative treatment for PRNN. We report the survival outcome and incidence of complications after stent implantation and compare the survival outcomes of ENPG and conservative treatment for PRNN followed by stent implantation. RESULTS: ICA stent pretreatment was performed in the 36 enrolled patients, among which 14 underwent ENPG, and 22 received conservative treatment. 27.8% patients died after a median follow-up of 15 months. The Kaplan-Meier estimates of overall survival were higher in the ENPG group than in the conservative treatment group. Karnofsky performance status (KPS) was significantly higher in the ENPG group than in the non-ENPG group. CONCLUSIONS: The innovative application of ICA stents is a promising treatment to improve outcomes in patients with PRNN invading the ICA who are unsuitable for ICA embolization, especially when followed by endoscopic surgery. However, methods to avoid postoperative cerebral ischemia and nasopharyngeal hemorrhage still require further study.

[Incidence of gastric cancer and risk factors in Suzhou cohort].

Objective: To describe gastric cancer incidence in Suzhou cohort, explore the environmental risk factors of gastric cancer in Suzhou, and provide appropriate suggestions for gastric cancer prevention and control. Methods: The participants were from the Suzhou cohort of China Kadoorie Biobank. Baseline survey was conducted from 2004 to 2008, followed by long-term follow-up until December 31, 2013. After the exclusion of those who had been previously diagnosed with peptic ulcer and malignant tumor reported at baseline survey and gastric cancer within six months after enrollment, a total of 50,136 participants were included. Cox proportional risk models were used to identify risk factors of gastric cancer and their hazard ratios in Suzhou. The effect modifications of gender on the association between risk factors and gastric cancer were analyzed. Results: In the follow-up of 7.19 years (median), 374 gastric cancers cases occurred. The standardized incidence was 94.57 per 100 000 person-years. Multivariate Cox proportional risk model analysis found that age (10 years old as a age group, HR=2.20, 95%CI: 1.92-2.53, P<0.001), current smoking (HR=1.84, 95%CI: 1.10-3.07 P=0.020), consumption of preserved vegetables weekly (HR=2.28, 95%CI: 1.28-4.07, P=0.005) and daily (HR=2.05, 95%CI: 1.16-3.61, P=0.013) were risk factors for gastric cancer. Female (HR=0.44, 95%CI: 0.25-0.76, P=0.003) and refrigerator use (10 years as a limit, HR=0.85, 95%CI: 0.74-0.97, P=0.016) were protective factors for gastric cancer. Further analysis showed that there was heterogeneity between males and females in the association between refrigerator use years and the incidence of gastric cancer (P=0.009), and there was an interaction effect between gender and refrigerator use on the incidence of gastric cancer (P=0.010). Conclusions: The incidence of gastric cancer in Suzhou cohort was high. The risk factors of gastric cancer varied. There was a synergistic interaction effect between gender and refrigerator use years on the incidence of gastric cancer.

[Mediating effect of physical activity on association between sedentary leisure-time and obesity indexes among hypertensive individuals].

Objective: To explore the mediating effect of physical activity on association between sedentary leisure-time and obesity indexes among hypertensive individuals. Methods: After excluding of those with a prior history of heart disease, stroke and cancer, a total of 20 178 hypertensive participants in the China Kadooire Biobank (CKB) study from Wuzhong district of Suzhou city were included. Mediating effect analysis was used to analyze the mediating effect of physical activity (PA) on correlation between sedentary leisure-time and body fat percentage (BFP), waist circumference (WC) and body mass index (BMI). Results: After adjusted for age, gender, smoking status, alcohol consumption, education levels, intake frequencies of meat and intake frequencies of fresh fruit, sedentary leisure-time (SLT) was negatively correlated with PA (ß=-0.246, P<0.001), but positively associated with BFP (ß=0.061, P<0.001), WC (ß=0.087, P<0.001) and BMI (ß=0.071, P<0.001). After including the mediator variable PA, the direct effect of SLT on obesity index was still significant. PA was negatively correlated with BFP, WC and BMI (ß=-0.052, -0.083 and -0.028, respectively, P<0.001). Analysis of mediating effect indicated that the association of SLT with BFP, WC and BMI were partly mediated by PA, the proportion of mediating effect was 20.820%, 23.421% and 9.915%. Stratified by gender, PA had mediating effect on SLT and all obesity indexes in women, while only on SLT and BFP and WC in men. Conclusions: There is a significant mediating effect of PA on correlation between SLT and obesity indexes among hypertensive individuals. Hypertensive patients should increase the level of physical activity and reduce sedentary behavior to achieve a profounder healthy effect.

[Association between perception of community environment and physical activity in residents in Suzhou].

Objective: To estimate physical activity level in residents in Suzhou and explore the association between community environment and physical activity level in local residents. Methods: Through multistage stratified random sampling, residents aged 25-64 years in Suzhou were surveyed by face-to face interview in 2017. Physical activity levels were assessed by the international physical activity questionnaire-long version (IPAQ-L). Perceptions of community environment were assessed by Neighborhood Environment Walkability Scale-Abbreviated (NEWS-A). Results: Among the local residents surveyed in Suzhou,the median of weekly total physical activity level was 3 610.42 MET-min/w. The level of occupational physical activity was higher than that of transportation, household and leisure-time related physical activity levels. After controlling for socio-demographic factors, public service access was negatively associated with the overall physical activity level (OR=0.522,95%CI:0.329-0.830), land-use mix-diversity was negatively associated with the level of occupational physical activity level (OR=0.701,95%CI: 0.492-0.999), infrastructure of walk and cycle ways was positively associated with occupational physical activity level (OR=1.603,95%CI:1.004-2.559); traffic hazards were negatively associated with the transportation physical activity level (OR=0.642,95%CI: 0.416-0.990); residential building density was positively associated with leisure-time physical activity level (OR=1.001,95%CI: 1.000-1.002), and the perceptions level of community environment were positively associated with the occupational, transportation, household and overall physical activity levels (OR=1.889,95%CI: 1.176-3.033;OR=1.671,95%CI: 1.120-2.495;OR=1.775,95%CI: 1.143-2.756;OR=1.593,95%CI: 1.079-2.350). Conclusion: Improving infrastructure of walk and cycle ways and beautifying community environment play an important role in increasing the physical activity level of the residents.

[Association between perceived built environment attributes and adults' leisure-time physical activity in four cities of China].

Objective: To explore the associations between perceived built environment attributes and adults' leisure-time physical activity in four cities of China. Methods: Multistage cluster random sampling method was used to select adults aged 25 to 64 in Hangzhou, Suzhou, Chengdu, and Qingdao. Data were collected from June 2017 to July 2018. The perception of the urban built environment was assessed by the neighborhood environment walkability scale-abbreviated (NEWS-A), and the physical activity was assessed by the International Physical Activity Questionnaire. Generalized linear mixed models were used to explore the relationship between the perceived built environment and leisure-time physical activities. Results: A total of 3 789 participants were included in the analysis. After adjusting for potential confounders, better access to public services (OR=1.34, 95%CI: 1.02-1.75) and higher aesthetic quality (OR=1.37, 95%CI: 1.09-1.73) were positively associated with the possibility of engaging in leisure-time physical activity in the past week. Similarly, these two attributes were positively associated with leisure-time walking. Higher scores on the perception of street connectivity were positively associated with leisure-time walking [exp(ß)=1.09, 95%CI: 1.00-1.19]. Higher residential density [exp(ß)=1.000 4, 95%CI:1.000 0-1.000 8], better access to physical activity destinations[exp(ß)=1.09, 95%CI: 1.00-1.19], and better aesthetics [exp(ß)=1.11, 95%CI:1.00-1.22] were associated with higher leisure-time physical activity. Similarly, these three attributes were positively associated with the possibility of meeting the WHO recommendations. Conclusion: Changing some urban built environment attributes may increase leisure-time physical activity.

[Association between family history of diabetes and incident diabetes of adults: a prospective study].

Objective: To evaluate the association betweew family history of diabetes and incident diabetes of adults. Methods: A total of 49 266 participants in the China Kadoorie Biobank (CKB) study from Wuzhong district of Suzhou city were included in the analysis, after the exclusion of those with heart disease, stroke, cancer and diabetes at baseline survey. The person-year of follow-up was calculated from the date on completion of baseline survey to the date on any firstly-occurred event, i.e., diabetes incidence, death, loss of follow-up, or December 31, 2013. Cox regression model was used to estimate the hazards ratios of the association between family history of diabetes and incident diabetes. Results: During 348 677 person-years of the follow-up (median 7.08 years), a total of 423 men and 791 women were diagnosed as having diabetes. Compared to those without diabetic family history, participants with family history of diabetes showed a higher risk of diabetes, with a HR (95%CI) of 1.90 (1.57-2.29), and the risk increased with the number of relatives suffering from diabetes (Pfor trend<0.05). The family history of maternal type, sibling type, and sibling and parental type had a statistically significant association with the risk of diabetes. The adjusted HR (95%CI) was 2.03 (1.45-2.77), 2.07 (1.56-2.68) and 2.39 (1.14-4.34), respectively. Modification effects of tobacco smoking, alcohol drinking, body mass index and physical activity on the association between diabetic family history and risk of diabetes were not observed in the study (Pfor interaction >0.05). Conclusions: Diabetic family history is associated with the increased incident diabetes, and the risk increased with the number of relatives suffering from diabetes.

[Years of potential life lost due to premature death of cardiovascular diseases among residents in Suzhou from 1987 to 2017].

From 1987 to 2017, cardiovascular disease (CVD) had been ranking the first cause of death in Suzhou, and the mortality rate showed an upward trend annual percentage changes (APC=0.62%, P=0.001), while the standardized mortality rate showed a downward trend (APC=-2.65%, P<0.001). The probability of premature death of CVD declined consistently from 7.06% in 1987 to 2.00% in 2017 (APC=-4.45%, P<0.001). When the life expectancy was set at 70, the potential years of life lost rate (PYLLR) decreased from 6.35‰ in 1987 to 3.30‰ in 2017, and the standardized PYLLR decreased from 7.30‰ to 2.68‰. When the life expectancy was set at 75, the PYLLR decreased from 10.12‰ to 5.19‰, and the standardized PYLLR decreased from 11.44‰ to 3.88‰. With the increase of years, all PYLLR and standardized PYLLR showed a significantly downward trend (APC=-2.51%--3.89%, P<0.001).

[Impact of menarche age on the near-term and long-term obesity of adult females].

Objective: To study the relationship between the age of menarche and the near-term/long-term obesity in adult women. Methods: We analyzed the baseline data of 30 895 women with complete data on menarche and body measurement that was from the China Kadoorie Biobank (CKB) study from 2004 to 2008. The age of menarche was divided into three groups: ≤12, 13-16 and ≥17 years old. Prematurity was set at age ≤12 years. Multivariate logistic regression was used to analyze the effects of menarche age on the near/long-term obesity in female adults. Results: The average menarche age of respondent appeared as (15.64±1.92) years old, with prematurity number as 1 421, accounting for 4.6% of the total numbers. Regarding the postponing of dates of birth, the age of menarche in women showed an advancing tendency. Among all the adult women under study, 803 developed near-term obesity, with the prevalence as 2.6%, while the number of long-term obesity was 3 738, accounting for 12.1%. Refining factors of age, lifestyle, menopausal status, hypertension and diabetes showed that the menarche age was related to the risks of both short-term and long-term obesity in women and the ORs (95%CI) were 2.45 (1.74-3.45) and 1.99 (1.69-2.34), respectively. There was no multiplicative interaction shown between the menarche age and menopausal status on long-term obesity (P=0.324). Conclusion: Premature menarche appeared a risk factor for near-term/long-term obesity in adult females.

[Association between psychosocial work environment and workplace bullying among office workers].

OBJECTIVE: To assess the prevalence of bullying in companies and health care center and identify the association between psychosocial environment and workplace bullying. METHODS: A total of 847 employees at in business building companies and 146 employees at one community health service center were invited to this survey by cluster sampling during October to December 2014, using anonymous questionnaires including the general demographic information, job characteristics, job stress core scale, the social capital scale, and NAQ-R. RESULTS: The rate of targets of bullying in the two kinds of workplaces were 13.1% and 5.6% respectively. Workplace bullying was associated with employee's education level(χ(2)=11.17, P=0.019)and the area his or her families live in(χ(2)=5.66, P=0.017). In addition, workplace bullying was significantly associated with psychosocial work environment. Job demand was positively correlated with workplace bullying (OR=2.24, 95% CI=1.34~3.74), and workplace social support was negatively associated with workplace bullying (OR= 0.33, 95% CI=0.18~0.60). CONCLUSION: Workplace bullying can be reduced by adjusting certain working conditions that negatively affect employees who are susceptible to being bullied, giving their individual and job characteristic. Moreover, workplace bullying could also be reduced if job demands are limited and job control and social capital are increased.

Corazonin reduces the spinning rate in the silkworm, Bombyx mori.

The insect neuropeptide, [Arg(7)]-corazonin was injected into larvae of the silkworm, Bombyx mori to investigate its influence on development and behavior. A single injection of 50 pmol of corazonin into the fourth and fifth instar larvae induced prolongation of the spinning period in all experimental groups except for those injected on day 10 of the fifth instar. The injection also caused a prolongation of the pupal period in some experimental groups, while it had no effect on the timing of larval ecdysis and the length of feeding period of the fifth instar. The spinning period was significantly prolonged even at a low dose of 1 pmol. Both the spinning rate and the rate of increase in hemolymph ecdysteroid level during the spinning stage were reduced by injection of corazonin. However, corazonin injection during days 5-7 of the fifth instar reduced the spinning rate without influencing the ecdysteroid level until the end of day 8, thereafter the rate of increase in hemolymph ecdysteroid level was slower in the corazonin-injected larvae than in the control larvae. Therefore, the suppressed ecdysteroid level observed in the corazonin-injected larvae appears to be a result rather than a cause of the reduced spinning rate. This study is the first published report for the corazonin effect on the behavior in insects.

[A study on breeding of "Ganzaoxian 47" from dry seeds of rice carried by recoverable satellite].

OBJECTIVE: To observe and investigate the variation and heredity of the offspring of dry seeds of rice carried by satellite, hence to select early maturing mutants, and to cultivate directly "Ganzaoxian 47" new varieties for production application. Isozymes analyses and studies of the new varieties and its original CK varieties were made. METHOD: Dry seeds of rice restorer line were carried to the space on board a recoverable satellite for 7 d in 1992. After recovery the seeds were planted in the field to study the agricultural characters, yield, disease resistance, rice quality and peroxidase isozymes change. RESULT: Its agricultural characters, yield, disease resistance, rice quality and peroxidase isozymes all showed distinct changes, and new varieties were cultivate directively for production application. CONCLUSION: It could be considered that certain variations of the rice seeds induced by the space conditions were heritable to the offspring's, and directive cultivation of new varieties is possible for production application. It could be used as a new method for mutagenic seed breeding.

Identification of a prothoracicostatic peptide in the larval brain of the silkworm, Bombyx mori.

Prothoracicotropic hormone (PTTH) stimulates ecdysteroid biosynthesis in the prothoracic gland (PG) of insects. A peptide inhibiting ecdysteroid biosynthesis in the PG was isolated from the extracts of 2,000 larval brains of the silkworm, Bombyx mori, using a protocol that included four reversed-phase high performance liquid chromatography procedures. The primary structure of this prothoracicostatic peptide (Bom-PTSP) was determined to be H-Ala-Trp-Gln-Asp-Leu-Asn-Ser-Ala-Trp-NH(2). This neuropeptide has the same sequence as Mas-MIP-I, a myoinhibitory peptide previously isolated from the ventral nerve cord of the tobacco hornworm, Manduca sexta, and is highly homologous with the N-terminal portion of vertebrate peptides of the galanin family. This peptide inhibited PTTH-stimulated ecdysteroidogenesis in the PG at both the spinning and feeding stages, which indicates that Bom-PTSP interferes with PTTH-stimulated ecdysteroidogenesis.

Quantification of ecdysteroids by immunoassay: comparison of enzyme immunoassay and radioimmunoassay.

The performance of enzyme immunoassay (EIA) and radioimmunoassay (RIA) in the quantitative analysis of ecdysteroids was compared. The EIA was found to be at least equivalent to the RIA with respect to analytical range and sensitivity and to be more comfortable with respect to safety and time saving. When biological samples were analyzed by both assays a good correlation (r = 0.83) was found. Since the EIA has certain advantages over the RIA, we now recommend the use of the former assay for the quantification of ecdysteroids.

Folliculostatins, gonadotropins and a model for control of growth in the grey fleshfly, Neobellieria (sarcophaga) bullata.

The sequences of two folliculostatic peptides of the fleshfly Neobellieria bullata have been determined recently. The first peptide (Neb-TMOF: H-NPTNLH-OH), originates from a 75 kDa precursor protein found in vitellogenic oocytes. The hexapeptide directly inhibits the synthesis of trypsin-like enzymes in the gut, and thus lowers the concentration of yolk polypeptides in the hemolymph. It also inhibits the biosynthesis of ecdysone in the larval ring gland. Therefore, it could also be named prothoracicostatic hormone (Neb-PTSH). The second peptide (Neb-colloostatin: H-SIV-PLGLPVPIGPIVVGPR-OH) acts on previtellogenic follicles and is a cleaved product of a collagen-like precursor molecule. Our results indicate that peptides that are cleaved from matrix proteins could act as growth-inhibiting factors. Gonadotropin releasing hormone (GnRH)-immunolike peptides were not identified, but progress is being made in the isolation and characterization of factors which stimulate cAMP production by the ovary. Using these results, a novel model of growth control in which matrix proteins play an important role as a potential source of growth regulators has been developed.

An ecdysiostatin from flies.

A bioassay for compounds with ecdysiostatic activity ('ecdysiostatins') was developed in order to prove the existence of an ecdysiostatin in blowfly larvae. The factor eluted by HPLC like Neb-TMOF (trypsin modulating oostatic factor), a hexapeptide that inhibits ecdysone biosynthesis. The ecdysiostatic activity of Neb-TMOF is specific, related peptides were less active or inactive. TMOF inhibits ecdysone biosynthesis rather than its secretion. It increases the cAMP level of ring glands. Effectors that elevate the intracellular cAMP can mimic the inhibitory effect of the ecdysiostatin. This suggests that cAMP may control steroidogenesis in fly larvae by shutting ecdysone biosynthesis. Thus, the hexapeptide acts as a prothoracicostatic hormone (PTSH) that controls ecdysone biosynthesis.