PATHWAYS OF MEDICAL PROGRESS

During the three decades that have passed, medical science has ascended to a high plateau of achievement. The climb has involved several pathways; among them: (1) the physiological approach toward disease as experiments which nature performs on organisms, (2) the more intelligent interpretation of the functional reactions of the body in disease in accordance with latest discoveries in physiology, (3) the supplementation of observable phenomena through use of laboratory instruments, (4) the assumption of active investigation both on patients and experimental animals by clinicians themselves, (5) the shuttling of problems between clinical and experimental laboratories and (6) correlated research in clinical and physiological departments. As we look down from the heights we have reached, we have reason to be pleased with our progress; but when we look ahead we become aware that there are still high mountain ranges to be climbed. We realize that their ascent can not be accomplished by employing merely the methods, equipment and strategy that have proved successful so far; we must improve the application of principles that are old and well established, and evolve others that are new. Above all, we from laboratories and clinics must join hands to help each other climb; and through correlated team-work overcome the great obstacles that jealous nature places in our way. I have ventured to suggest a few directions which such mutual help may take. They include (1) means by which new fundamental discoveries can be utilized more quickly by clinicians and practitioners of medicine; (2) plans by which younger clinical investigators can be given approximately the same opportunity for training in research technique as their colleagues entering experimental sciences; (3) pleas that the shuttling of problems between hospitals and laboratories of fundamental science may continue in order that the ultimate significance of clinical results may be better understood and that the applicability of fundamental discoveries to nature's experiments may be tested; (4) judicious combination of talents of laboratory and clinical workers, whenever this leads to greater economy of effort and does not infringe upon the primary duties of each participant to his calling. The spirit of correlation which is involved in all these plans of advance is a silent force which grows not only through mutual interest in each other's problems but also through frank respectful criticism of each other's trends. With such a spirit of correlated effort science marches on.     

Disease of geese caused by a new herpesvirus

A goose flock farmed outdoors in south-eastern Queensland suffered an outbreak of peracute disease with high death rate (97%). Small button ulcers and large plaques overlying lymphocyte aggregates were present on the mucosa of the small intestine of affected birds. Small white foci of necrosis and focal haemorrhages were seen in the livers. Numerous intranuclear inclusion bodies were observed microscopically in hepatocytes and a herpesvirus which grew rapidly in chicken kidney cells was isolated from tissues. Duck virus enteritis (DVE) was suspected but DVE antiserums failed to neutralise the virus. Further serological studies with a limited range of known avian herpesviruses have failed to identify the virus. Experimental transmission resulted in high mortality in geese (100%), lower mortality in ducklings and nil mortality in chickens. Surveillance studies showed no evidence of infection in domestic and wild birds beyond the original farm and the infection appears not to have been established in the area. Wild ducks, which were frequent visitors to the farm dam, were considered the most likely source of the infection.     

甘蓝型油菜(Brassica napus)无花瓣突变体“ Ap-Tengbe ”花瓣性状的遗传规律

本项研究旨在探明甘蓝型油菜突变体Ａｐ－Ｔｅｎｇｂｅ无花瓣性状的遗传规律,‘Ａｐ－Ｔｅｎｇｂｅ’和德国栽培品种‘Ｆａｌｃｏｎ’之间通过正反交产生两个方向的Ｆ１,ＢＣ１－１（Ｆ１和‘Ａｐ－Ｔｅｎｇｅｂｅ’之间）,ＢＣ１－２（Ｆ１和‘Ｆａｌｃｏｎ’之间）以及Ｆ２各遗传群体,根据田间各遗传群体ＰＤｇｒ（花瓣度）的观察和统计,作者提出‘Ａｐ－Ｔｅｎｇｅ’突变体无花瓣性状的遗传由细胞质和两对核隐性基因共同控制     

The impact of naturally-occurring,trans-placental bluetongue virus serotype-8 infection on reproductive performance in sheep

Infection with bluetongue virus serotype (BTV)-8 occurred in ruminants in 2006 in Central-Western Europe. The trans-placental passage of this virus has been demonstrated in naturally- and experimentally-infected cattle and in experimentally-infected sheep. Trans-placental transmission is potentially important in the ‘over-wintering’ of this virus and its subsequent impact on reproductive performance. This epidemiological study was carried out on a sheep flock in Belgium that had experienced a severe outbreak of BTV-8 infection, and where the seroprevalence had increased from 1.3% to 88% between January and November 2007. In total, 476 lambs and 26 aborted fetuses from 300 ewes, lambing at four distinct time periods, were investigated between November 2007 and May 2008.The following evidence suggested that BTV-8 infection occurred in utero: (1) positive PCR results from splenic tissue from aborted fetuses (n = 4); (2) fetal malformations suggestive of BTV infection (n = 10); (3) positive PCR results from red blood cells in-lambs (n = 7), and (4) the presence of antibody at birth in viable lambs prior to the intake of colostrum (n = 9). The evidence provided by this investigation strongly suggests that trans-placental BTV-8 infection occurs in naturally-infected sheep and the impact of infection on the reproductive performance of such a naïve flock was considerable, with up to 25% of ewes aborting and with flock fertility reduced by 50%. The contribution of in utero-infected lambs to the over-wintering of BTV appears limited.     

Vascular Endothelial (VEGF) and Epithelial Growth Factor (EGF) as Well as Platelet‐Activating Factor (PAF) and Receptors are Expressed in the Early Pregnant Canine Uterus

The aim of this study was to investigate the course of expression of platelet‐activating factor (PAF), PAF‐receptor (PAF‐R), epidermal growth factor (EGF), EGF‐R, vascular endothelial growth factor (VEGF), VEGF‐R1 and VEGF‐R2 in uterine tissue during canine pregnancy. For this purpose, 20 bitches were ovariohysterectomized at days 10–12 (n = 10), 18–25 (n = 5) and 28–45 (n = 5) days after mating, respectively. The pre‐implantation group was proven pregnant by embryo flushing of the uterus after the operation, the others by sonography. Five embryo negative, that is, non‐pregnant, bitches in diestrus (day 10–12) served as controls. Tissue samples from the uterus (placentation sites and horn width, respectively) were excised and snap‐frozen in liquid nitrogen after embedding in Tissue Tec^®. Extraction of mRNA for RT‐PCR was performed with Tri‐Reagent. In the embryos, mRNA from all factors except VEGF was detected. In the course of pregnancy, significantly higher expression of PAF and PAFR as well as VEGF and VEGFR2 during the pre‐implantation stage than in all other stages and a strong upregulation of EGF during implantation were characteristic. The course of EGF was in diametrical opposition to the course of the receptor. These results point towards an increased demand for VEGF, EGF and PAF during the earliest stages of canine pregnancy.