Croblongifolin, a new anticancer clerodane from Croton oblongifolius

A new furoclerodane, croblongifolin, together with one known clerodane, crovatin and one known labdane, nidorellol, were isolated from the stem bark of Croton oblongifolius. Structures were established based on spectroscopic and X-ray analysis. Croblongifolin showed a significant cytotoxicity against various human tumor cell lines including HEP-G2, SW620, CHAGO, KATO3 and BT474.     

Four new sesquiterpenoid derivatives from the heartwood of Mansonia gagei

Four new sesquiterpenoid derivatives named mansonones N (1), O (2), P (3), and Q (4) were isolated from a dichloromethane extract of the heartwood of Mansonia gagei, a plant used in folk medicine in Thailand. Their structures were resolved on the basis of spectrometric data interpretation and the single-crystal X-ray analysis of 1 and 2.     

A longitudinal study of LH, gonadal and adrenal steroids in four intact Asian bull elephants (Elephas maximus) and one castrate African bull (Loxodonta africana) during musth and non-musth periods

During their annual musth cycle, adult African and Asian bull elephants have increased gonadal androgens (testosterone [T], dihydrotestosterone [DHT], androstenedione [A4]). Because musth is a physiologically and psychologically stressful time, this study was conducted to investigate whether the adrenal glands (stimulated by stress) increase production of both glucocorticoids and androgens during musth. Weekly serum samples were taken for 11-15 months from four intact adult Asian bull elephants, and from a castrate African bull elephant who exhibits musth. Testosterone, androstenediol (A5), A4, luteinizing hormone (LH), cortisol, and dehydroepiandrosterone (DHEA) were measured in each sample. In three of the four intact bulls, all hormones measured increased during musth. Adrenal androgens were strongly correlated with LH and testicular androgens, though not to cortisol. None of the hormones measured in the castrate bull increased during his musth cycles. While the significance of adrenal activity in the elephant during musth has yet to be determined, this study provides evidence that the adrenal gland actively produces both glucocorticoids and androgens during musth in the Asian elephant.     

ACTH stimulation in four Asian bull elephants (Elephas maximus): an investigation of androgen sources in bull elephants

The phenomenon of musth is a very stressful event, both behaviorally and physiologically. An ACTH stimulation test was conducted in four adult Asian bull elephants to investigate the possibility that the classical hypothalamic-pituitary-adrenal (HPA) axis is active during musth, resulting in an increase in adrenally produced steroids. Serum cortisol, testosterone (T), androstenedione (A4), androstenediol (A5), and dehydroepiandrosterone (DHEA) were measured. Cortisol increased 3-10 times above baseline in response to ACTH stimulation, and DHEA doubled. A4 and A5 were erratic, while testosterone decreased significantly in all bulls. The pattern of results suggests that the adrenal steroid increase which occurs during musth results from some mechanism other than the classical HPA axis.     

Effects of Russell's viper venom fractions on systemic and renal hemodynamics.

Changes in systemic and renal hemodynamics induced by Russell's viper venom are well established. The component of the venom responsible for hemodynamic alteration has not been identified. By Sephadex column chromatography five fractions of Russell's viper (Daboia russellii siamensis) venom were isolated. Each venom fraction consisted of phospholipase A2, proteolytic enzyme, phosphomonoesterase, phosphodiesterase, arginine ester hydrolase and hyaluronidase of varying activities. Hemodynamic effects of each venom fraction including mean arterial pressure, cardiac output, systemic and renal vascular resistance, renal blood flow and glomerular filtration rate were studied in five groups of dogs; each group had four dogs. Minimal hemodynamic changes were observed in dogs receiving venom fraction I. Increased renal vascular resistance with diminution of renal blood flow and glomerular filtration rate was observed in dogs receiving venom fractions II, III, IV and V. A markedly increased renal vascular resistance with maximal decrease in renal blood flow and glomerular filtration rate was caused by fraction III of the venom with highest PLA2 and proteolytic enzyme activities. However, renal hemodynamic changes appeared to correlate better with proteolytic enzyme activity than PLA2 activity. The findings suggested the proteolytic enzyme as an important determinant of hemodynamic alteration. Fractional excretion of Na was increased in dogs injected with venom fraction IV, and is presumed to be due to the inhibition of tubular reabsorption of Na by a natriuretic factor in this venom fraction.     

A pilot experiment for production of Malayan krait antivenom: immunization of rabbits with Bungarus candidus venom

Immunization with Bungarus candidus venom was performed in four rabbits at high dose (initial dose, 75 microg/kg) and low dose (initial dose, 50 microg/kg). Each dose group consisted of two rabbits; one rabbit received the venom subcutaneously (s.c.) and the other intradermally (i.d.). The venom was injected as emulsified solutions with the same volume of Freund's complete adjuvant until the 4th immunization, thereafter as plain solutions. By stepwise increments of the immunizing dose, the higher dose group received a dose of 200 microg/kg and the lower dose group 150 microg/kg after the 5th immunization, respectively. Thereafter, seven additional immunizations were performed within six months. All rabbits were sacrificed two weeks after the last immunization (12th). Antilethal activity of the immunized antisera thus obtained was determined not only with the homologous venom but also with two heterologous venoms from Bungarus fasciatus and Bungarus flaviceps. Immunodiffusion analysis was also performed with these venoms. The results obtained in this pilot trial provided useful information for production of Malayan krait antivenom at Queen Saovabha Memorial Institute.     

A potential new serotype of Riemerella anatipestifer isolated from ducks in Thailand

Eighty isolates of Riemerella anatipestifer representing 71 outbreaks of riemerellosis in Thailand between 1994 and 1999 were serotyped using the gel diffusion precipitin test. Based on the precipitation patterns, 25 serological profiles containing one to three antigenic determinants were recognized. Heat-stable antigens of the organism reacted with antisera raised against 16 known serotypes and an untypable strain 698/95. The most prevalent serotype appeared to be serotype 7, followed by serotypes 5, 10, 21 and 1. Further study demonstrated that the untypable strain probably represents a new serotype. Analysis of the polymerase chain reaction-amplified rrs genes for restriction fragment length polymorphisms verified the inclusion of strain 698/95 within the species R. anatipestifer and supported earlier work excluding strain 670/89, which had originally been designated the reference strain of serotype 20. Therefore, it is suggested that the strain 698/95 could be adopted as a replacement for the reference strain of serotype 20. Attention should be paid to strains with multiple antigenic factors as they may be useful for the preparation of vaccines.     

Acute kidney injury and pneumothorax are risk factors for mortality in persistent pulmonary hypertension of the newborn in Thai neonates

Objectives: To describe the clinical characteristics, diagnostic methods, treatment modalities, and complications, and identify the mortality risk factors, of infants with short-term persistent pulmonary hypertension of the newborn (PPHN).

Methods: The clinical data of infants diagnosed with PPHN at Hat Yai Hospital from January 2010 to February 2014 were retrospectively reviewed. Cox proportional hazard regression analysis was performed to assess factors associated with mortality.

Results: The records of 119 infants were analyzed. Of these, 47 died giving an in-hospital mortality rate of 39.5%. The prevalence of PPHN (based on inborn births) was 2.8 per 1000 live births. The mean gestational age and birth weight were 39.1?±?1.6 weeks and 3044?±?563?g, respectively. Multivariate Cox regression analysis indicated that pneumothorax [adjusted hazard ratio (HR)?=?2.07 (95% CI 1.09–3.93)] and acute kidney injury [adjusted HR?=?2.99 (95% CI 1.59–5.61)] were factors associated independently with an increased risk for death, while infants who received total parenteral nutrition [adjusted HR?=?0.22 (95% CI 0.10–0.50)] had lower mortality.

Conclusion: A high mortality rate of PPHN was observed in this study. Significantly higher mortality was noted in infants complicated with pneumothorax and acute kidney injury.