Selective conservatism in trauma management: a South African contribution

Trauma in South Africa has been termed the malignant epidemic. This heritage was the result of a violent colonial legacy which spawned the apartheid system of injustice and the struggle against it The Apartheid regime created overcrowding, unemployment, social stagnation, and the disruption of normal family life. These were the catalysts for the incredible amount of criminal and interpersonal conflict in South Africa over the last 50 years. African townships such as Soweto in Johannesburg and Umlazi in Durban were crime-ridden ghettoes where the apartheid police were more interested in fueling the "black on black" violence rather than trying to curb it. Baragwanath (Chris Hani-Baragwanath) and King Edward the VIII Hospital in Durban were the "trauma care epicenters" on the fringes of these huge urban conurbations. Both were designated black hospitals and both were underfunded and dilapidated. Even the architecture was similar, with prefabricated, poorly ventilated structures serving as wards and clinics in both institutions. Trauma volumes consisted of between 10 and 20 laparotomies on weekend nights at the height of political unrest. This led to vast individual experience in several areas of trauma typified by Demetriades' experience with 70 penetrating cardiac injuries. In this setting of limited resources and an overwhelming volume of trauma, selective conservatism as a surgical philosophy took root and has profoundly influenced the way the world manages trauma. We detail and illustrate the evolution of this approach and its continued application.

Prostanoid receptor expression by human airway smooth muscle cells and regulation of the secretion of granulocyte colony-stimulating factor

The prostanoid receptors on human airway smooth muscle cells (HASMC) that augment the release by IL-1β of granulocyte colony-stimulating factor (G-CSF) have been characterized and the signaling pathway elucidated. PCR of HASM cDNA identified products corresponding to EP2, EP3, and EP4receptor subtypes. These findings were corroborated at the protein level by immunocytochemistry. IL-1β promoted the elaboration of G-CSF, which was augmented by PGE2. Cicaprost (IP receptor agonist) was approximately equiactive with PGE2, whereas PGD2, PGF2α, and U-46619 (TP receptor agonist) were over 10-fold less potent. Neither SQ 29,548 nor BW A868C (TP and DP1receptor antagonists, respectively) attenuated the enhancement of G-CSF release evoking any of the prostanoids studied. With respect to PGE2, the EP receptor agonists 16,16-dimethyl PGE2(nonselective), misoprostol (EP2/EP3selective), 17-phenyl-ω-trinor PGE2(EP1selective), ONO-AE1-259, and butaprost (both EP2selective) were full agonists at enhancing G-CSF release. AH 6809 (10 μM) and L-161,982 (2 μM), which can be used in HASMC as selective EP2and EP4receptor antagonists, respectively, failed to displace to the right the PGE2concentration-response curve that described the augmented G-CSF release. In contrast, AH 6809 and L-161,982 in combination competitively antagonized PGE2-induced G-CSF release. Augmentation of G-CSF release by PGE2was mimicked by 8-BrcAMP and abolished in cells infected with an adenovirus vector encoding an inhibitor protein of cAMP-dependent protein kinase (PKA). These data demonstrate that PGE2facilitates G-CSF secretion from HASMC through a PKA-dependent mechanism by acting through EP2and EP4prostanoid receptors and that effective antagonism is realized only when both subtypes are blocked concurrently.

Incidence of benign pathology in patients undergoing hepatic resection for suspected malignancy

BACKGROUND

Confirming the presence of hepatic or proximal bile duct malignancy pre-operatively remains difficult and some patients may undergo surgical resection for suspected malignant lesions which subsequently turn out to be benign. The aim of this study was to establish whether improvements in pre-operative staging might better identify this patient population.

METHODS

Analysis of a prospectively collected database, which has been maintained in our unit since 1988.

RESULTS

Of 250 consecutive patients undergoing hepatic resection for presumed malignancy, 18 (7.2%) were shown to have benign pathology. These "false positive" rates were 4 out of 160 (2.5%) resections for colorectal metastases, 4 out of 49 (8.2%) resections for other solid hepatobiliary tumours and 10 out of 41 (24.4%) resections for hilar cholangiocarcinoma. Four of the 18 patients (22%) developed post-operative complications but there was no postoperative mortality.

CONCLUSION

Although hepatic resection remains a potentially curative procedure for patients with tumours involving the liver parenchyma or proximal bile ducts, pre-operative confirmation of malignancy remains difficult. Despite appropriate investigation a subset of patients with benign disease will still be subjected to major hepatic resection which should be undertaken in a specialist unit.

Colorectal foreign bodies

OBJECTIVE

A pictorial review of colorectal foreign bodies and their extraction.

METHODS

A prospective data-base and photographic record of patients who presented with retained colorectal foreign bodies at our institution has been maintained since 1995. Information regarding the foreign body, clinical presentation and extraction technique were documented.

RESULTS

All 13 patients were male: age range 2-66 years. Seven were Caucasian, 4 African and 1 Asian. The foreign bodies included a penknife, an aerosol deodorant spray can, a blue plastic tumbler, a plastic bag containing two bank-notes and some marijuana, a plastic packet containing fish hooks, a penlight torch, a broomstick, a battery powered vibrator, a primus stove, a cap of an aerosol can, a piece of wire, a piece of hosepipe wrapped with wire and an iron bar. They entered the alimentary tract for a variety of reasons; anal autoeroticism (3), concealment (2), attention seeking behaviour (3), accidental (1), assault (2) and to alleviate constipation (2). Plain radiographs accurately demonstrated the site of the foreign body in 8 patients. Extraction was at laparotomy in 2 patients with peritonitis and in 3 who required extraction by colotomy. In 7 patients who had transanal extraction, four required general anaesthesia to facilitate extraction and extraction was possible under conscious sedation in the emergency room in three. The remaining patient extracted the foreign body himself and presented to hospital with a rectal perforation.

CONCLUSION

The emergency room physician must confirm the presence of a rectal foreign body. Extraction in the emergency room is usually not possible and patient's with retained rectal foreign bodies should be referred to a colorectal surgeon.

E-ring 8-isoprostanes are agonists at EP2- and EP4-prostanoid receptors on human airway smooth muscle cells and regulate the release of colony-stimulating factors by activating cAMP-dependent protein kinase

8-Isoprostanes are bioactive lipid mediators formed via the nonenzymatic peroxidation of arachidonic acid by free radicals and reactive oxygen species. However, their cognate receptors, biological actions, and signaling pathways are poorly studied. Here, we report the effect of a variety of E- and Falpha-ring 8-isoprostanes on the release of granulocyte/macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) from human airway smooth muscle (HASM) cells stimulated with interleukin-1beta (IL-1beta). The elaboration of GM-CSF and G-CSF by IL-1beta was inhibited and augmented, respectively, in a concentration-dependent manner by 8-iso-prostaglandin (PG) E(1) and 8-iso-PGE(2), but not by 8-iso-PGF(1alpha), 8-iso-PGF(2alpha), and 8-iso-PGF(3)alpha. AH 6809 (6-isopropoxy-9-oxoxanthine-2-carboxylic acid), an EP(1)-/EP(2)-/DP-receptor blocking drug, antagonized the inhibitory effect of 8-iso-PGE(1) and 8-iso-PGE(2) on GM-CSF output with an affinity consistent with an interaction at prostanoid receptors of the EP(2)-subtype. In contrast, the facilitation by 8-iso-PGE(1) and 8-iso-PGE(2) of G-CSF release was unaffected by AH 6809 and the selective EP(4)-receptor antagonist L-161,982 [4'-[3-butyl-5-oxo-1-(2-trifluoromethyl-phenyl)-1,5-dihydro-[1,2,4]triazol-4-ylmethyl]-biphenyl-2-sulfonic acid (3-methyl-thiophene-2-carbonyl)-amide]. However, when used in combination, AH 6809 and L-161,982 displaced 5-fold to the right the 8-iso-PGE and 8-iso-PGE concentration-response curves. The opposing (1)effect of E-ring (2)8-isoprostanes on GM-CSF and G-CSF release was mimicked by 8-bromo-cAMP and abolished in cells infected with an adenovirus vector encoding an inhibitor protein of cAMP-dependent protein kinase (PKA). Together, these data demonstrate that E-ring 8-isoprostanes regulate the secretion of GM-CSF and G-CSF from HASM cells by a cAMP- and PKA-dependent mechanism. Moreover, antagonist studies revealed that 8-iso-PGE(1) and 8-iso-PGE(2) act solely via EP(2) -receptors to inhibit GM-CSF release, whereas both EP(2)- and EP(4)-receptor subtypes positively regulate G-CSF output.

Preoperative biliary stenting--a prequel to pancreatic resection in selected patients

INTRODUCTION

Biliary drainage is necessary to improve immediate survival in patients with profound co-morbidities associated with jaundice. We report on our experience with this category of patients in whom subsequent pancreaticoduodenectomy was performed.

PATIENTS AND METHODS

In the period January 2001-June 2002, 6 patients underwent biliary drainage to reverse potentially fatal complications or to optimise nutritional status. There were 2 female and 4 male patients (age range 50-70 years). The reasons for biliary drainage were suboptimal albumin levels in all patients, cholangitis in 4 patients and renal impairment in 2 male patients and profound acute jaundice in 1.

RESULTS

There was failure of stent placement at endoscopic retrograde cholangiopancreatography (ERCP) in 3 patients. Two had an ERCP performed before referral and had a metal stent deployed at percutaneous transhepatic cholangiography (PTC). In the other a plastic stent was placed at a combined PTC/ERCP session. The 3 others had stents placed by ERCP. None of the patients had complications related to the stenting procedure. All the lesions were deemed resectable following imaging by ultrasound and computed tomography (CT) scan. Laparotomy with intent to resect was planned once the complications had resolved. The average duration of stenting before surgery was 46 days (range 12-100 days). All patients underwent pancreatoduodenectomy. One patient developed postoperative superficial wound sepsis, which resolved with topical management. There were no perioperative deaths. The postoperative hospital stay ranged from 10 to 21 days. Histological examination revealed pancreatic adenocarcinomas in 4 patients, an ampullary tumour in 1 patient and a non-functioning islet cell tumour in the other.

CONCLUSION

Biliary drainage for complications should not be regarded as definitive treatment. It optimises co-morbidity factors and allows staging so that resection can be carried out successfully in selected patients.

Identification in human airways smooth muscle cells of the prostanoid receptor and signalling pathway through which PGE2 inhibits the release of GM-CSF

1. The prostanoid receptor(s) on human airways smooth muscle (HASM) cells that mediates the inhibitory effect of PGE(2) on interleukin (IL)-1 beta-induced granulocyte/macrophage colony-stimulating factor (GM-CSF) release has been classified. 2. IL-1 beta evoked the release of GM-CSF from HASM cells, which was suppressed by PGE(2), 16,16-dimethyl PGE(2) (nonselective), misoprostol (EP(2)/EP(3)-selective), ONO-AE1-259 and butaprost (both EP(2)-selective) with pIC(50) values of 8.61, 7.13, 5.64, 8.79 and 5.43, respectively. EP-receptor agonists that have selectivity for the EP(1)-(17-phenyl-omega-trinor PGE(2)) and EP(3)-receptor (sulprostone) subtypes as well as cicaprost (IP-selective), PGD(2), PGF(2 alpha) and U-46619 (TP-selective) were poorly active or inactive at concentrations up to 10 microM. 3. AH 6809, a drug that can be used to selectively block EP(2)-receptors in HASM cells, antagonised the inhibitory effect of PGE(2), 16,16-dimethyl PGE(2) and ONO-AE1-259 with apparent pA(2) values of 5.85, 6.09 and 6.1 respectively. In contrast, the EP(4)-receptor antagonists, AH 23848B and L-161,982, failed to displace to the right the concentration-response curves that described the inhibition of GM-CSF release evoked by PGE(2) and ONO-AE1-259. 4. Inhibition of GM-CSF release by PGE(2) and 8-Br-cAMP was abolished in cells infected with an adenovirus vector encoding an inhibitor protein of cAMP-dependent protein kinase (PKA) but not by H-89, a purported small molecule inhibitor of PKA. 5. We conclude that prostanoid receptors of the EP(2)-subtype mediate the inhibitory effect of PGE(2) on GM-CSF release from HASM cells by recruiting a PKA-dependent pathway. In addition, the data illustrate that caution should be exercised when using H-89 in studies designed to assess the role of PKA in biological processes.

E-ring 8-isoprostanes inhibit ACh release from parasympathetic nerves innervating guinea-pig trachea through agonism of prostanoid receptors of the EP3-subtype

1. In the present study, we examined the effect of E-ring 8-isoprostanes on cholinergic neurotransmission in guinea-pig trachea and identified the receptor(s) involved. As isoprostanes are isomeric with prostaglandins, PGE(2) and sulprostone (a selective EP(3)-receptor agonist) were examined in parallel. 2. 8-Iso-PGE(1), 8-iso-PGE(2) (0.1 nm-1 microM), sulprostone (1 nm-1 microM) and PGE(2) (1 microM) suppressed EFS-evoked [(3)H]ACh release from guinea-pig trachea in a concentration-dependent manner, producing 39.5, 53.9, 61.2 and 59.9% inhibition, respectively, at 1 microM. It should be noted that an established maximum effective concentration was not determined. 3. Neither SQ 29,548 (1 microm; a TP-receptor antagonist) nor AH 6809 (10 microM; an EP(1)-/EP(2)-/DP-receptor antagonist) reversed the inhibitory effect of these compounds. 4. L-798,106, a novel and highly selective EP(3)-receptor antagonist, produced a parallel shift to the right of the concentration-response curves that described the inhibitory action of sulprostone on EFS-evoked contractile responses in guinea-pig vas deferens (an established EP(3)-receptor-expressing tissue), from which a mean pA(2) of 7.48 was derived. On guinea-pig trachea, L-798,106 also antagonised sulprostone-induced inhibition of EFS-induced twitch responses, with similar potency (mean pA(2)=7.82). 5. The inhibitory effects of 8-iso-PGE(1), 8-iso-PGE(2), sulprostone and PGE(2) on EFS-induced [(3)H]ACh release was blocked by L-798,106 at a concentration (10 microM) that binds only weakly to human recombinant EP(1)-, EP(2)- and EP(4)-receptor subtypes expressed in HEK 293 cells. 6. These data suggest that E-ring 8-isoprostanes, PGE(2) and sulprostone inhibit EFS-evoked [(3)H]ACh release from cholinergic nerves innervating guinea-pig trachea, by interacting with prejunctional prostanoid receptors of the EP(3)-subtype.

The role of preoperative biopsy in pancreatic cancer

BACKGROUND

Cyto-histological diagnosis of pancreatic pathology in the management of suspected pancreatic malignancy is re-evaluated in the light of evolving trends in management and tissue sampling.

METHODS

The literature on cyto-histological diagnosis of pancreatic pathology was reviewed over the period 1977-2003.

RESULTS AND CONCLUSION

Endoluminal techniques of tissue sampling carry less risk of tumour seeding and are the sampling methods of choice for potentially resectable lesions if a tissue diagnosis will alter therapy. Endosonar-guided biopsy in expert hands appears to be the most reliable tissue sampling technique. Transcoelomic sampling methods should be reserved for those with un-resectable disease. All methods of cyto-histological diagnosis have high specificity but have a low negative predictive value. Therefore, potentially resectable lesions that are highly suspicious for malignancy should be explored even if pre-operative histology or cytology is negative.

Hepatic resection for benign non-cystic liver lesions

BACKGROUND

Hepatic resection is indicated for a variety of benign conditions because of persistent symptoms, uncertainty regarding the diagnosis or the risk of malignant transformation. The aim of this study was to assess the indications for and outcome of hepatic resection for benign non-cystic liver lesions in a specialist hepatobiliary unit.

PATIENTS AND METHODS

All patients who had undergone hepatic resection for benign non-cystic hepatic lesions between 1989 and 2001 were identified from a prospective database for analysis.

RESULTS

A total of 49 patients (40 women, 9 men) with a mean age of 43 years (range 21-75 years) underwent resection of non-cystic benign lesions. Indications for operation included suspected liver cell adenoma (n=11), suspicion of malignancy (11), persistent symptoms attributable to the lesion (20) or chronic sepsis (7). The final diagnosis was focal nodular hyperplasia (n=12), haemangioma (12), adenoma (8), sclerosing cholangitis (5), inflammatory pseudotumour (4), intrahepatic cholelithiasis (3), chronic hepatic abscess (3), benign biliary fibrosis (I) and leiomyoma (I). Major anatomical hepatic resections were performed in 44 patients, and 5 patients underwent a segmentectomy or minor atypical resection. Median operating time was 215 min (range 45-450 min) and median blood loss was 875 ml (range 200-4000 ml). Ten patients (20%) required a median blood transfusion of 2 units (range 2-8 units). The median postoperative stay was 10 days (range 4-33 days). There were no deaths, but complications occurred in 15 patients (27%).

CONCLUSIONS

Hepatic resection can be safely recommended for selected patients with a variety of benign non-cystic hepatic lesions. A small group of patients undergo resection as a result of inability to rule out a malignant process, but the large majority will be operated on because of either their malignant potential or related symptoms.

Octreotide lowers gastric mucosal blood flow in normal and portal hypertensive stomachs

BACKGROUND

The vasoactive peptide octreotide has an established role in controlling variceal hemorrhage. The mechanism of action is believed to be a reduction in splanchnic blood flow. A decrease in splanchnic blood flow should be mirrored by a decrease in gastric mucosal blood flow (GMBF). Laser Doppler flowmetry (LDF) should detect changes in GMBF.

METHODS

In seven normal volunteers and four patients with portal hypertension, 100 micro g of octreotide was administered as an intravenous bolus. Continuous LDF measurements were then made at a single point on the midantrum for at least 10 min and plotted against time for each subject.

RESULTS

After a variable period of stabilization, GMBF decreased in all subjects except one. This was statistically significant in both the controls and the patients with portal hypertension.

CONCLUSIONS

Octreotide decreases GMBF in normal and portal hypertensive stomachs. Laser Doppler is a useful and minimally invasive tool to assess the effect of drugs on GMBF.

Neural stem cells

The adult vertebrate central nervous system (CNS) consists of four major differentiated cell types: neurons, astrocytes, oligodendrocytes and ependymal cells. Historically, there has been a disagreement on how these differentiated cell types are generated in the CNS. Progress remains hindered by the complexity of cell structure in this system, the lack of specific cell surface markers to identify distinct cell types and the presence of numerous transit amplifying cell populations that rapidly generate early progenitors. At present, it is clear that some cells, termed neural stem cells, can generate neurons as well as astrocytes and oligodendrocytes of the glial lineage both in vitro and in vivo. Additionally, specific neural stem cell populations have also exhibited tissue lineage plasticity.

Attenuated gastric mucosal blood flow predicts non-healing of benign gastric ulcers

BACKGROUND

A subset of benign gastric ulcers do not respond to therapy and may require surgery. A predictor of non-healing may allow modification of therapy. Gastric mucosal blood flow plays an important role in gastric ulcer pathogenesis and healing.

AIMS

Mucosal blood flow was measured with Laser Doppler flowmetry at initiation of and during therapy to assess the variability of mucosal blood flow in healing and non-healing ulcers as a possible predictor of healing.

METHODS AND SUBJECTS

Mucosal blood flow was measured at the mid-antrum in 105 normal human stomachs and on the circumference of 26 benign gastric ulcers. The gastric ulcers were followed up with repeat endoscopy and repeat measurements were made.

RESULTS

The ulcers that healed had significantly higher mucosal blood flow than normal stomachs at both initial and follow-up measurement (59.8 +/- 26.1 vs. 75.7 +/- 17.5 and 69.8 +/- 13.7). The refractory ulcers persistently had significantly lower mucosal blood flow than normal stomachs and healing ulcers (59.8 +/- 26.1 vs. 45.2 +/- 21.9 and 39.2 +/- 6.7).

CONCLUSIONS

Gastric mucosal blood flow seems to increase in response to mucosal injury and healing. Attenuation of this response is associated with delayed healing. Attenuated peri-ulcer mucosal blood flow may predict non-healing of a benign gastric ulcer.

Origin of Cryptococcus neoformans var. neoformans diploid strains

The basidiomycetous yeast Cryptococcus neoformans is an important human fungal pathogen. Two varieties, C. neoformans var. neoformans and C. neoformans var. gattii, have been identified. Both are heterothallic with two mating types, MATa and MATalpha. Some rare isolates are self-fertile and are considered occasional diploid or aneuploid strains. In the present study, 133 isolates, mostly from Italian patients, were investigated to detect the presence of diploid strains in the Igiene Università Milano culture collection. All of the diploid isolates were further investigated by different methods to elucidate their origins. Forty-nine diploid strains were identified by flow cytometry. PCR fingerprinting using the (GACA)(4) primer showed that the diploid state was associated with two specific genotypes identified as VN3 and VN4. Determination of mating type on V8 juice medium confirmed that the majority of the strains were sterile. PCR and dot blotting using the two pheromone genes (MFa and MFalpha) as probes identified 36 of the 49 diploid isolates as MATa/alpha. The results of pheromone gene sequencing showed that two allelic MFalpha genes exist and are distinct for serotypes A and D. In contrast, the MFa gene sequence was conserved in both serotype alleles. Amplification of serotype-specific STE20 alleles demonstrated that the diploid strains contained one mating locus inherited from a serotype A parent and one inherited from a serotype D parent. The present results suggest that diploid isolates may be common among the C. neoformans population and that in Italy and other European countries serotype A and D populations are not genetically isolated but are able to recombine by sexual reproduction.

The Cryptococcus neoformans STE11alpha gene is similar to other fungal mitogen-activated protein kinase kinase kinase (MAPKKK) genes but is mating type specific

Partial sequence analysis of the Cryptococcus neoformans MATalpha mating type locus revealed the presence of a gene with substantial sequence similarity to other fungal mitogen-activated protein (MAP) kinase kinase kinase (MAPKKK) genes. The C. neoformans gene, designated STE11alpha, showed the highest degree of similarity to the Neurospora crassa nrc-1, Schizosaccharomyces pombe byr2 and Saccharomyces cerevisiae STE11 genes. A polymerase chain reaction-mediated sib-selection technique was successfully adapted for the purpose of disrupting STE11alpha. C. neoformans ste11alphaDelta mutants were found to be sterile, consistent with the phenotypes of ste11 and byr2 mutants in S. cerevisiae and S. pombe respectively. Haploid ste11alphaDelta mutants were also found to be unable to produce hyphae, suggesting that the C. neoformans gene is functionally conserved when compared with its S. cerevisiae MAPKKK counterpart. Comparison of the wild-type STE11alpha strain with a ste11alphaDelta disruptant for virulence using the mouse model showed that the ste11alphaDelta strain was less virulent, but the difference was only minor. In spite of some of the conserved functions of STE11alpha, linkage analysis showed that STE11alpha is only found in mating type alpha strains. These results demonstrate that, although functionally conserved, the mating pathway in C. neoformans has a unique organization.

Regulation of repulsion versus adhesion by different splice forms of an Eph receptor

Eph tyrosine kinase receptors and their membrane-bound ephrin ligands mediate cell interactions and participate in several developmental processes. Ligand binding to an Eph receptor results in tyrosine phosphorylation of the kinase domain, and repulsion of axonal growth cones and migrating cells. Here we report that a subpopulation of ephrin-A5 null mice display neural tube defects resembling anencephaly in man. This is caused by the failure of the neural folds to fuse in the dorsal midline, suggesting that ephrin-A5, in addition to its involvement in cell repulsion, can participate in cell adhesion. During neurulation, ephrin-A5 is co-expressed with its cognate receptor EphA7 in cells at the edges of the dorsal neural folds. Three different EphA7 splice variants, a full-length form and two truncated versions lacking kinase domains, are expressed in the neural folds. Co-expression of an endogenously expressed truncated form of EphA7 suppresses tyrosine phosphorylation of the full-length EphA7 receptor and shifts the cellular response from repulsion to adhesion in vitro. We conclude that alternative usage of different splice forms of a tyrosine kinase receptor can mediate cellular adhesion or repulsion during embryonic development.

Mapping of the Cryptococcus neoformans MATalpha locus: presence of mating type-specific mitogen-activated protein kinase cascade homologs

In this study we investigated the relationship between the MATalpha locus of Cryptococcus neoformans and several MATalpha-specific mitogen-activated protein (MAP) kinase signal transduction cascade genes, including STE12alpha, STE11alpha, and STE20alpha. To resolve the location of the genes, we screened a cosmid library of the MATalpha strain B-4500 (JEC21), which was chosen for the C. neoformans genome project. We isolated several overlapping cosmids spanning a region of about 71 kb covering the entire MATalpha locus. It was found that STE12alpha, STE11alpha, and STE20alpha are imbedded within the locus rather than closely linked to the locus. Furthermore, three copies of MFalpha, the mating type alpha-pheromone gene, a MATalpha-specific myosin gene, and a pheromone receptor (CPRalpha) were identified within the locus. We created a physical map, based on the restriction enzyme BamHI, and identified both borders of the MATalpha locus. The MATalpha locus of C. neoformans is approximately 50 kb in size and is one of the largest mating type loci reported among fungi with a one-locus, two-allele mating system.

Generalized potential of adult neural stem cells

The differentiation potential of stem cells in tissues of the adult has been thought to be limited to cell lineages present in the organ from which they were derived, but there is evidence that some stem cells may have a broader differentiation repertoire. We show here that neural stem cells from the adult mouse brain can contribute to the formation of chimeric chick and mouse embryos and give rise to cells of all germ layers. This demonstrates that an adult neural stem cell has a very broad developmental capacity and may potentially be used to generate a variety of cell types for transplantation in different diseases.

Inferior vena caval injury in the firearm era

BACKGROUND

This study compared the outcome of intra-abdominal caval injuries in the current era of firearm injuries with the outcome during the previous era of stab wounds.

METHODS

Patients with intra-abdominal vena caval injuries treated at King Edward VIII Hospital, Durban, from December 1990 to December 1995 were reviewed. This group was compared with a similar cohort reviewed a decade earlier.

RESULTS

The historical group consisted of 28 patients and the current group of 26 patients. Modes of injury in the historical group were: stabs (15, 53%), firearm injuries (7, 33%), blunt trauma (4, 14%) and iatrogenic injuries (2, 7%). Modes of injury in the current group were: stabs (5, 19%), firearm injuries (17, 65%) and blunt trauma (4, 16%). Mortality rose from 35.7% in the historical group to 88% in the current series. This mortality figure included 5 patients who died later from complications of the associated injuries.

CONCLUSIONS

Firearm injuries are more destructive than stab wounds. The increase in firearm injuries partly explains this higher mortality. However, the failure to apply current concepts of abbreviated laparotomy and damage control combined with excessive delays in transferring patients to theatre have contributed to this high mortality.

Identification of a neural stem cell in the adult mammalian central nervous system

New neurons are continuously added in specific regions of the adult mammalian central nervous system. These neurons are derived from multipotent stem cells whose identity has been enigmatic. In this work, we present evidence that ependymal cells are neural stem cells. Ependymal cells give rise to a rapidly proliferating cell type that generates neurons that migrate to the olfactory bulb. In response to spinal cord injury, ependymal cell proliferation increases dramatically to generate migratory cells that differentiate to astrocytes and participate in scar formation. These data demonstrate that ependymal cells are neural stem cells and identify a novel process in the response to central nervous system injury.

Universal primary colonic repair in the firearm era

All patients with colonic trauma treated at King Edward VIII Hospital, Durban, from August 1993 to May 1994 underwent primary repair of the colonic wound. They were evaluated prospectively to assess the mode of injury and outcome variables. Colonic injuries were sustained by 102 patients. These were inflicted by gunshots (62), stabs (22), shotguns (14), and blunt trauma (4). The transverse colon was injured most frequently (53). All shotgun injuries were multiple. Average time from admission to theatre was similar for shocked and non-shocked patients. Eighty-seven patients had simple closure (18 deaths) and 15 required resection and anastomosis (eight deaths). Ten patients died in the first 48 h, and 16 died subsequently owing to multiple-organ systems dysfunction. The mortality rates were stabs 9% (2), gunshots 27% (17), shotguns 50% (7), and 0% for blunt trauma. Septic morbidity was seen in 16 but was not related to breakdown of the colonic repair. Implementation of strategies to reduce preoperative time delays and use damage control principles for the management of massive trauma should be evaluated as methods of reducing mortality.

Cloning and characterisation of the adenosyl phosphosulphate kinase gene from Aspergillus nidulans

The sD gene of Aspergillus nidulans has been cloned by heterologous screening of rationally selected cosmids. Co-transformation of the sD50 mutant JMP1 confirmed the presence of a functional gene. Sequence analysis determined this gene to be 680 bp in length, containing a 59-bp intron and encoding a protein of 206 amino acids. A protein-sequence comparison revealed a similarity to the C-terminal region of ATP sulphurylase, the sC gene product. Further sequence comparison revealed differences in a consensus sequence ATP-binding motif, indicating non-functionality of the APS kinase-like domain of ATP sulphurylase, and confirms sD as the gene encoding APS kinase in A. nidulans.

The different forms of the prolactin receptor in the rat corpus luteum: developmental expression and hormonal regulation in pregnancy

The corpora lutea of pregnancy in the rat are highly dependent on the action of PRL and PRL-like hormones to hypertrophy and to produce progesterone needed for the maintenance of gestation. Two forms of the PRL receptor (PRL-R), designated as long (PRL-RL) and short (PRL-RS), have been described in rat tissues. To determine whether both forms are present in the corpus luteum during pregnancy and to examine the developmental and hormonal regulation of their expression, total RNA isolated from corpora lutea at different stages of pregnancy and from highly luteinized granulosa cells subjected to different hormonal treatments were analyzed by semiquantitative RT-PCR. Immunoblotting of luteal proteins from early and late pregnancy was also performed to determine if the pattern of PRL-R proteins follows that of PRL-R messenger RNA (mRNA) expression. In addition, the correlation between the well characterized PRL-regulated gene, 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD), and PRL-R gene expression was investigated during the time of luteolysis. Both PRL-RL and PRL-RS mRNA and protein were expressed in corpora lutea of pregnancy, with the long form being the most dominant at all stages. Whereas no changes in mRNA level of either PRL-RL or PRL-RS were found until day 20 of gestation, a profound decline in PRL-R mRNA and protein for both receptor types occurred at the end of pregnancy. This drop in PRL-R expression was accompanied by a sharp and abrupt expression of 20alpha-HSD mRNA. Studies performed in vivo and in luteinized cells in culture indicate that PRL can up-regulate the expression of the PRL-RL mRNA, an effect prevented by the tyrosine kinase inhibitor, genistein. PRL-RL mRNA was also selectively increased by cAMP. In summary, the results of this investigation have established that: 1) the corpus luteum of pregnancy expresses both the short and long forms of the PRL-R with the long form being more abundant; 2) the mRNA for both forms of the PRL-R remains at constant levels throughout pregnancy but drops before parturition; 3) the decline in PRL-R mRNA at the end of pregnancy is accompanied by a dramatic rise in 20alpha-HSD; 4) PRL is able to increase the expression of PRL-R mRNA; and that 5) both A kinase and tyrosine kinase mediated pathways appear to participate in the up-regulatory mechanism involved in PRL-R mRNA expression.

Merging a PICU and MICU: a debate

One of the possible combinations when merging specialty units is combining a pediatric intensive care unit with an adult intensive care unit. The response related to the merging of these specialty units solicits very intense, diverse opinions. The authors address this controversial issue in a debate forum to present both sides of the issue.

The decidual prolactin receptor and its regulation by decidua-derived factors

Decidualization of the endometrial stroma in the rat gives rise to two different cell populations, located either mesometrially or antimesometrially in the uterus. We have previously shown that the rat decidua is the site of production and action of a PRL-like hormone. In this investigation we examined, using reverse transcription-PCR, whether and which type of PRL receptor (PRL-R) messenger RNA (mRNA) is expressed in the decidua, whether the receptor is confined only to one cell population, and whether the PRL-R expression is regulated by decidua-derived factors. The results indicate that the uterus of pseudopregnant rats does not express the PRL-R and that decidualization does not trigger a rapid appearance of PRL-R mRNA. It is only 3 days after the induction of decidualization that the long form of the PRL-R was first expressed. Thereafter, mRNAs for both the short (PRL-RS) and the long (PRL-RL) form became detectable in both antimesometrial and mesometrial decidua, although PRL-RL mRNA was much more abundant than PRL-RS. As development proceeded, PRL-R mRNA decreased and disappeared specifically from the antimesometrial decidua, whereas the mesometrial decidua continued to express this receptor mRNA. Concomitant with down-regulation of the PRL-R in the antimesometrial tissue was a rather abrupt expression of activin A. In contrast, the mesometrial tissue that maintained high levels of PRL-R mRNA expressed little activin A, but produced an activin-binding protein, alpha(2)-macroglobulin (alpha(2)MG). To determine whether activin A and alpha(2)MG regulate PRL-R expression, antimesometrial and mesometrial cells were separated by elutriation and maintained in culture in the presence or absence of activin A, alpha(2)MG, or follistatin. Just after cell separation, both cell populations expressed PRL-R, but not activin A. Within 6 h, activin A mRNA and protein became highly expressed in the mesometrial cells, whereas PRL-RL mRNA became undetectable. In contrast, activin A mRNA was at very low levels in the antimesometrial cells, and no activin A protein could be detected in the medium for at least 12 h. In these cells PRL-RL mRNA remained elevated. Addition of activin A to antimesometrial cells caused a marked down-regulation of PRL-RL mRNA expression, whereas addition of alpha(2)MG and follistatin to mesometrial cells prevented the disappearance of PRL-R. In summary, the results of this investigation 1) indicate that decidualization of the endometrial stroma induces the appearance of both forms of the PRL-R mRNAs; 2) show differential expression of the PRL-R mRNA in the two-cell population forming the decidua; 3) establish that this differential expression is due to two key decidual molecules, activin A and alpha(2) macroglobulin; and 4) demonstrate that activin A can cause the decidual cells to lose the PRL-R and that the disappearance of the decidual PRL-R can be prevented by addition to the culture of two activin binding proteins, follistatin and alpha(2) MG.

Merging PICU and MICU: expanding nurse competencies

Unit mergers offer an opportunity for nurses to acquire additional skills. A model for unit mergers is presented. The authors describe how didactic and clinical competencies serve as a foundation upon which the nurse develops proficiency and expertise in a new subspecialty.

Prolactin receptor messenger ribonucleic acid expression in the ovary during the rat estrous cycle

We have investigated the relative amounts and sites of synthesis during the rat estrous cycle of the two ovarian mRNAs encoding the long and short PRL receptors (PRL-R). Quantitative analysis has revealed that the mRNA encoding the short PRL-R is consistently present throughout the cycle in lower quantities than the long receptor mRNA. Both receptor mRNAs are at maximal levels during proestrus, decline to their lowest level of expression during estrus, then gradually rise in metestrus and diestrus. By in situ hybridization, both receptor mRNAs are present during early proestrus in corpora lutea, in the granulosa cell layers of large Graafian follicles, and in the interstitial cells closely associated with these follicles. The short PRL-R mRNA was detected at significant levels in the granulosa-derived cumulus oophorus and in the thecal cell region at this time, whereas the long PRL-R mRNA was only weakly expressed in these cell types. In contrast, the long PRL-R mRNA was present at higher levels, compared to the short receptor mRNA, in the granulosa cells of preantral follicles in the interior of the ovary. On late proestrus, the long PRL-R mRNA was found predominantly in the mural granulosa cells of large Graafian follicles and in corpora lutea, but by estrous morning this mRNA appeared to be mostly restricted to the corpora lutea. This distribution was maintained through estrous evening and metestrous morning. On diestrus, both mRNAs were present in some corpora lutea and in the granulosa cell layer in a subset of the larger Graafian follicles, but were detected at even higher levels in the interstitial cells surrounding these follicles; again, the long receptor mRNA appeared to be only weakly expressed in the thecal cell region of these follicles. These results indicate that the levels and locations of PRL-R mRNA expression in the ovary, and therefore, the potential responsiveness of the ovary to PRL, change throughout the reproductive cycle. Furthermore, the presence of both receptor mRNAs in several different ovarian cell types suggests that both of these receptor forms play important roles in PRL physiology in the ovary.

Changes in prolactin receptor expression during pregnancy in the mouse ovary

We have isolated the cDNA encoding the cytoplasmic domain of a long form of the mouse PRL receptor (PRL-R). The mRNA for this long form PRL-R and the three mRNAs encoding short mouse PRL-R that have been previously characterized are all expressed in both the liver and ovary. The relative amounts of these receptor forms differ between tissues, however. In addition, the structure of one of the short receptor forms may not be identical in the liver and ovary. Within the ovary, the abundance and sites of synthesis of the four PRL-R mRNAs vary during pregnancy. Expression of the two most abundant PRL-R mRNAs increases significantly at midgestation. Expression of PRL-R mRNA is detected in the corpus luteum throughout pregnancy, while increased receptor mRNA levels are evident in the granulosa cells of a subset of Graafian follicles toward the end of pregnancy and during lactation. Some differences are also observed in the expression patterns of the individual receptor forms. Most notably, one of the short form PRL-R mRNAs is uniquely detected in atretic follicles in early to midgestation.

Simulation of coherent energy transfer in an alpha-helical peptide by Fermi resonance

A mechanism by which NH stretching quanta are coherently transported along a chain of hydrogen bonded peptide groups is demonstrated by classical simulation of a section of the alpha-helical peptide poly(L-alanine). Vibrational motion takes place on a complex energy surface constructed from earlier ab initio and empirical surfaces. A speculative hypothesis of the biological role of this mechanism is presented, and the critical parameters governing the dynamics are identified and discussed.

Rocking promotes differentiated properties in LLC-PK cells by improved oxygenation

Previous studies from our laboratory indicated that in contrast to cells cultured under still conditions, LLC-PK cells cultured under conditions of continuous rocking exhibit pH-modulated ammonia production and also manifest lower levels of lactate dehydrogenase activity. In the present studies, we assessed whether other metabolic features and parameters of differentiation are modified by rocking. Rocked, as contrasted with still, cultures exhibited decreased medium lactate production and increased cellular ATP content consistent with heightened oxidative metabolism. Still cultures did not exhibit either dome formation or sodium-dependent alpha-methylglucoside uptake until the cultures reached full confluency. By contrast, rocked cultures underwent dome formation as well as enhanced alpha-methylglucoside uptake during the growth phase, and these parameters were quantitatively greater than in still culture even after full confluency was achieved. Thus rocking promotes several functions, which can reflect differentiation in LLC-PK cells. To determine whether provision of adequate oxygen accounts for the enhancement of cellular metabolism and differentiated functions by rocking, still cultures grown in a high oxygen concentration of 36% were compared with standard cultures grown in 18% oxygen. The high oxygen environment resulted in the development of pH-modulated ammonia production, a decrease in lactate dehydrogenase activity, lower medium lactate formation, increased ATP levels, more copious dome formation, and increased alpha-methylglucoside uptake. Thus rocking promotes cellular metabolism and differentiated functions by the provision of adequate oxygenation.