Transition in sexual system and sex chromosome evolution in the tadpole shrimp Triops cancriformis.

Transitions in sexual system and reproductive mode may affect the course of sex chromosome evolution, for instance by altering the strength of sexually antagonistic selection. However, there have been few studies of sex chromosomes in systems where such transitions have been documented. The European tadpole shrimp, Triops cancriformis, has undergone a transition from dioecy to androdioecy (a sexual system where hermaphrodites and males coexist), offering an excellent opportunity to test the impact of this transition on the evolution of sex chromosomes. To identify sex-linked markers, to understand mechanisms of sex determination and to investigate differences between sexual systems, we carried out a genome-wide association study using restriction site-associated DNA sequencing (RAD-seq) of 47 males, females and hermaphrodites from one dioecious and one androdioecious population. We analysed 22.9 Gb of paired-end sequences and identified and scored >3000 high coverage novel genomic RAD markers. Presence-absence of markers, single-nucleotide polymorphism association and read depth identified 52 candidate sex-linked markers. We show that sex is genetically determined in T. cancriformis, with a ZW system conserved across dioecious and androdioecious populations and that hermaphrodites have likely evolved from females. We also show that the structure of the sex chromosomes differs strikingly, with a larger sex-linked region in the dioecious population compared with the androdioecious population.

[Perihilar cholangiocarcinoma (Klatskin tumor)]. / Zentrales Gallengangskarzinom (Klatskin-Tumor).

Perihilar cholangiocarcinoma or Klatskin tumors are a rare entity arising from the extrahepatic bile duct bifurcation. Considering the close anatomical relationship of the bile duct bifurcation with the portal vein bifurcation and hepatic arteries, surgical treatment is demanding. With an incidence of only 2-4 cases/100,000 population/year patients should be referred to a specialized center. The tumors are usually poorly differentiated adenocarcinomas growing diffusely along the duct and also the perineural sheath. Only radical surgery offers a curative option and currently surgical strategy usually consists of en bloc resection of the bile duct, extended liver resection and portal vein resection. Proximal and lateral safety margin R0 resections are technically very demanding procedures because of the local anatomy.

Spontaneous pneumopericardium, pneumomediastinum and subcutaneous emphysema: unusual complications of asthma in a 2-year-old boy.

A 2-year-old boy presented to the emergency department with a history of sudden onset of cough, dyspnoea and a slight expiratory wheeze on the right lung base. He also had subcutaneous emphysema on the left side of the chest anteriorly. Chest x ray confirmed subcutaneous emphysema and also revealed pneumomediastinum and pneumopericardium. He had had no previous episode and was not known to have asthma. He was apyrexial but had a raised white cell count. The eosinophil count was within normal limits. He was successfully treated with nebulised salbutamol, steroids, antibiotics and high flow oxygen. He made a good recovery and was discharged after 7 days. This case highlights the need for a high index of suspicion of asthma in very young children presenting for the first time with such complications.

Kaposi's sarcoma-associated herpesvirus latent and lytic gene expression as revealed by DNA arrays.

Kaposi's sarcoma-associated herpesvirus (KSHV; human herpesvirus 8) is associated with three human tumors, Kaposi's sarcoma, primary effusion lymphoma (PEL), and multicentric Castleman's disease. KSHV encodes a number of homologs of cellular proteins involved in the cell cycle, signal transduction, and modulation of the host immune response. Of the virus complement of over 85 open reading frames (ORFs), the expression of only a minority has been characterized individually. We have constructed a nylon membrane-based DNA array which allows the expression of almost every ORF of KSHV to be measured simultaneously. A PEL-derived cell line, BC-3, was used to study the expression of KSHV during latency and after the induction of lytic replication. Cluster analysis, which arranges genes according to their expression profile, revealed a correlation between expression and assigned gene function that is consistent with the known stages of the herpesvirus life cycle. Furthermore, latent and lytic genes thought to be functionally related cluster into groups. The correlation between gene expression and function also infers possible roles for KSHV genes yet to be characterized.

Evolution of animal body plans: the role of metazoan phylogeny at the interface between pattern and process.

Comprehensive integrative studies are the hallmark of evolutionary developmental biology. A properly defined phylogenetic framework takes a central place in such analyses as the meeting ground for observation and inference. Molecular phylogenies take this place in many current studies on animal body plan evolution. In particular, 18S rRNA/DNA sequence analyses have yielded a new view of animal evolution that is often contrasted with a presumed traditional or classical view. First, I expose this traditional view to be a simplified historical abstraction that became textbook dogma. Second, I discuss how two recent important studies of animal body plan evolution, examining the evolution of the platyhelminth body plan and the evolutionary significance of indirect development and set-aside cells, have actively incorporated two problematic aspects of the newly emerging molecular view of animal evolution: incomplete and unresolved phylogenies.

Transthoracic endoscopic sympathectomy for hyperhidrosis and Raynaud's phenomenon.

Over an 80 month period, 53 transthoracic endoscopic sympathectomies were performed in 34 patients. The indications for surgery were palmar hyperhidrosis in 20 procedures (38%), palmar and axillary hyperhidrosis in eight procedures (15%), Raynaud's phenomenon in 23 procedures (43%), and combined palmar hyperhidrosis and Raynaud's phenomenon in two procedures (4%). Follow-up data, obtained by a self-assessment postal questionnaire, was available for 47 procedures in 30 patients (91%). Fourteen out of 15 procedures (93%) performed for palmar hyperhidrosis, all eight procedures (100%) for palmar and axillary hyperhidrosis and 14 out of 22 procedures (64%) performed for Raynaud's phenomenon produced an immediate improvement in symptoms. These improvements were sustained in 13 procedures (87%) performed for palmar hyperhidrosis, all procedures performed for palmar and axillary hyperhidrosis (100%) but only 10 procedures (45%) performed for Raynaud's phenomenon at a median follow-up of 16, 34 and 44.5 months respectively. There were no deaths nor postoperative Horner's syndrome in these patients. The only minor complications were two small pneumothoraces. Compensatory sweating was observed after 24 procedures (51%). These results confirm that transthoracic endoscopic sympathectomy is a simple, safe and effective procedure. In patients with hyperhidrosis, the results are excellent and prolonged; in patients with Raynaud's phenomenon, immediate improvement can be achieved but the symptoms may return with time.

Intracranial pressure in pigs with surgically induced acute liver failure.

Cerebral edema has now been noted to occur frequently in patients dying of fulminant hepatic failure. In the present study, intracranial pressure was monitored in an animal model of acute liver failure. Acute liver failure was induced surgically by hepatic devascularization. Serial monitoring of the electroencephalogram revealed progressive slowing of the frequency with decreasing amplitude. Elevation of the blood ammonia was also observed from baseline values of 64 +/- 12 SE to 744 +/- 97 mumol/liter. Monitoring of the intracranial pressure with a subdural pressure transducer demonstrated a progressive and reproducible rise from 12.8 +/- 2.5 mm Hg immediately after the operation to a mean value of 51.6 +/- 11.8 mm Hg just before death 6--12 hr later. At autopsy, the brains of the test animals were found to be swollen with flattened cortical gyri. In the control animals, intracranial pressure rose slightly but returned toward normal levels (8.0 +/- 2.5 mm Hg) 8 hr after laparotomy and remained normal until their death. There was a statistically significant difference between intracranial pressure levels of the test animals and those of the controls (P less than 0.01). Intravenous methylprednisolone (2.0 g initially followed by 0.5 g every 2 hr) administered immediately before and after hepatic devascularization prevented rises in intracranial pressure but had no effect when given 4 hr after operation. The early and progressive increase in intracranial pressure was an unexpected finding, and an assessment of such a sequence in patients with fulminant hepatic failure is currently in progress.

Hepatobiliary imaging: a comparison of 99Tcm-dihydrothioctic acid and 99Tcm-pyridoxylidene glutamate in the non-jaundiced patient.

A comparison of two hepatobiliary imaging agents, 99Tcm-dihydrothioctic acid (99Tcm-DHT) and (99Tcm-pyridoxylidene glutamate (99Tcm-PG) has been carried out in 44 non-jaundiced patients. Thirty-one patients were admitted for investigation of upper abdominal pain and 13 patients were volunteers who were undergoing treatment for unrelated conditions. Satisfactory liver images were obtained with both agents in patients without liver disease, but they were inferior to those seen after 99Tcm-sulphur colloid. 99Tcm-PG produced clearer images of the gall-bladder and bile ducts than 99Tcm-DHT. Non-visualization of the gall-bladder was interpreted as gall-bladder disease; in patients with inflammatory gall-bladder disease no gall-bladder image was seen (nine 99Tcm-DHT, nine 99Tcm-PG). The gall-bladder was also not demonstrated in two of the volunteers' group (one 99Tcm-DHT, one 99Tcm-PG), nor was a gall-bladder seen in five patients whose abdominal pain was not due to acute cholecystitis. Despite this, there was agreement between the results of imaging and oral cholecystography in 21 out of 22 subjects. 99Tcm-PG is non-toxic, cheap and rapidly excreted by the liver into the bile. A 99Tcm-PG scan would be useful when rapid diagnosis is required in suspected acute cholecystitis when conventional contrast radiology is unlikely to be of value.

Hepatobiliary imaging: the use of 99Tcm-pyridoxylidene glutamate scanning in jaundiced adults and infants.

99Tcm-pyridoxylidene glutamate (99Tcm-PG) scans have been carried out in 24 jaundiced adults (mean total bilirubin 255 mumol/l and 11 infants with prolonged obstructive jaundice (mean total bilirubin 165 mumol/l). Absence of radioactivity in the gut was interpreted as complete biliary obstruction which was the cause of jaundice in ten adults and six infants. Using this criterion occlusion or patency of the bile ducts was correctly determined in 21 adults and eight infants. False-negative gut images were found in one adult and two infants, and three scans were inconclusive (two adults, one infant). The scan was unable to show details of the site of obstruction or pathology but the technique was simple and atraumatic and was safely performed in patients with serious complications, e.g. renal failure, coagulation defects, septicaemia. In infants the 99Tcm-PG scan compared well with the 131I rose bengal faecal excretion test and with liver biopsy in the investigation of prolonged obstructive jaundice. Repeat scans in infants with biliary atresia were used to assess postoperative bile drainage. It is suggested that 99Tcm-PG scanning is useful screening test in difficult cases of jaundice. It is especially useful in frail patients, and patients with complications.

New perspectives on biliary atresia.

An investigation into the aetiology, diagnosis, and treatment of biliary atresia was carried out because the prognosis remains so poor.In an electron microscopical study no viral particles or viral inclusion bodies were seen, nor were any specific ultrastructural features observed. An animal experiment suggested that obstruction within the biliary tract of newborn rabbits could be produced by maternal intravenous injection of the bile acid lithocholic acid.A simple and atraumatic method of diagnosis was developed using(99) (m)Tc-labelled compounds which are excreted into bile. Two compounds, (99m)Tc-pyridoxylidene glutamate ((99m)Tc-PG) and (99m)Tc-dihydrothioctic acid ((99m)Tc-DHT) were first assessed in normal piglets and piglets with complete biliary obstruction. Intestinal imaging correlated with biliary tract patency, and the same correlation was found in jaundiced human adults, in whom the (99m)Tc-PG scan correctly determined biliary patency in 21 out of 24 cases. The (99m)Tc-PG scan compared well with liver biopsy and (131)I-Rose Bengal in the diagnosis of 11 infants with prolonged jaundice.A model of extrahepatic biliary atresia was developed in the newborn piglet so that different methods of bile drainage could be assessed. Priorities in biliary atresia lie in a better understanding of the aetiology and early diagnosis rather than in devising new bile drainage procedures.

Validation of "transit renography" for the determination of the intrarenal distribution of plasma flow: comparison with the microsphere method in the anaesthetized rabbit and pig.

1. The spectrum of transit times of sodium o-iodohippurate (Hippuran) through the kidney can be derived from an 131I- (or 123I-) labelled Hippuran renogram by deconvolution. In the rabbit and pig, as has previously been shown in man, the frequency distribution curve for the transit times was bimodal. Since the transit time is likely to be proportional to the nephron length, the area of the first mode is likely to represent plasma flow to the shorter outer cortical nephrons whereas the delayed mode represents flow to the long juxtamedullary nephrons. 2. This interpretation was tested by simultaneously comparing renography with the microsphere method of measuring intrarenal plasma flow distribution in 12 rabbits and two pigs with a variety of anaesthetics. A close agreement was found between both methods for the percentage of plasma flow distributed to the outer cortical nephrons, thus supporting the use of "transit renography" to determine the intrarenal distribution of plasma flow.