Neisseria canis infection: a case report

The third case report, which is the first in Australia, of human infection with Neisseria canis is documented. This is the first case report in which the pathogenicity of this organism for humans is unequivocally demonstrated.

Characterization of an autoantigen associated with chronic ulcerative stomatitis: the CUSP autoantigen is a member of the p53 family

A unique clinical syndrome has been described in which patients have chronic oral ulceration and autoantibodies to nuclei of stratified squamous epithelium. We have characterized the autoantibodies from patients sera and found that the major autoantigen is a 70 kDa epithelial nuclear protein. Sequencing of the cDNA for this protein, chronic ulcerative stomatitis protein, revealed it to be homologous to the p53 tumor suppressor and to the p73 putative tumor suppressor, and to be a splicing variant of the KET gene. The p53-like genes, p73 and the several KET splicing variants, are recently described genes of uncertain biologic and pathologic significance. This study provides the first clear association of a p53-like protein with a disease process.

Characterization of a SR protein from Trypanosoma brucei with homology to RNA-binding cis-splicing proteins

The protozoan parasite Trypanosoma brucei relies on trans-splicing to process its mRNAs. A novel nuclear serine/arginine (SR)-rich trypanosomal protein (TSR1) was characterized which contains two RNA recognition motifs. The TSR1 protein appears to be homologous to RNA-binding SR proteins of the cis-splicing machinery from higher eukaryotes. Moreover, in the yeast two-hybrid system, TSR1 is able to interact with the human splicing factors involved in the recognition of the 3' splicing site (U2AF35/U2AF65). In both procyclic and bloodstream forms of T. brucei, TSR1 was found to localize in the nucleus. In the bloodstream stage TSR1 showed the speckles pattern characteristic of SR proteins involved in cis-splicing. Moreover, TSR1 was able to specifically bind the spliced leader (SL) RNA involved in trans-splicing in trypanosomes by the yeast three-hybrid system. These and other observations suggest that TSR1 may be involved in trans-splicing in T. brucei.

Look before you leap: stratify before you standardize

This paper presents a mathematical model to show the conditions in which age standardization can be used to summarize age-specific rates for comparison purposes over calendar time. It shows that the conditions for valid comparison depend on the type of measure used for comparison, that is, difference, ratio, or percent change. If the measure for comparison is a difference of the standardized rates at two time points, then the age-specific rates need to maintain a constant rate difference over time for the comparison to be valid. If the measure for comparison is a ratio or percent change of the standardized rates at two time points, then the age-specific rates need to maintain a constant rate ratio over time for the comparison to be valid. Since in reality, as shown by our Canadian empirical data, age-specific rates do not always maintain a consistent pattern over time, it is recommended that one should always stratify the data to look at patterns of age-specific rates before applying age standardization.

Overexpression of mutant ras in human melanoma increases invasiveness, proliferation and anchorage-independent growth in vitro and induces tumour formation and cachexia in vivo

Malignant melanoma is the deadliest form of skin cancer. Previous studies have shown that the incidence of ras mutation increases with progression of melanoma, but that such mutations may not be present in the earliest radial growth phase melanomas. Recently it has been proposed that introduction of ras mutations into cells deficient in tumour suppressor genes such as p16 (INK4a) is sufficient to induce characteristics of cellular transformation such as anchorage-independent growth and tumour formation in vivo. To test this hypothesis in human melanoma, mutant N-ras, mutant H-ras or wild-type H-ras genes were transfected by electroporation into WM35 cells, a p16-deficient human melanoma cell line of low invasive potential. Increased expression of mutant ras p21 enhanced anchorage-dependent cell growth on tissue culture plastic. In addition, overexpression of mutant N-ras and H-ras, but not of wild-type H-ras, increased the experimental invasive potential, inducing anchorage-independent growth in soft agar, increasing cell motility measured by time-lapse video microscopy, and increasing invasiveness through reconstituted basement membranes. Finally, overexpression of mutant H-ras in melanoma cells was shown to increase tumorigenicity and to induce cachexia when H-ras transfected cell lines were injected subcutaneously in severe combined immunodeficiency (SCID) mice. Thus the addition of activating ras mutations to a melanoma cell line already deficient in p16 leads to enhanced proliferation, survival and migration in vitro and to enhanced subcutaneous tumour formation in vivo. This phenotype is typical of the behaviour of vertical growth phase (VGP) melanoma, and we propose that activation of the ras signalling pathway in the presence of deletions in p16 or related tumour suppressors can induce the VGP melanoma phenotype.

WT1: what has the last decade told us?

When positionally cloned in late 1989, it was anticipated that mutations within the Wilms' tumour suppressor gene (WT1) would prove responsible for this common solid kidney cancer of childhood. Characterisation of the WT1 expression pattern and of the structure of the encoded protein isoforms and their mode of action has now spanned almost a decade. WT1 proteins act as nucleic acid-binding zinc finger-containing transcription factors involved in both transactivation and repression. These activities are facilitated and constrained by interactions with other proteins. Expression analyses and knockout mice indicate that WT1 protein plays a critical role in normal kidney and gonad development. Specific constitutional WT1 mutations results in several urogenital anomaly syndromes. While only 10% of sporadic Wilms' tumours do display WT1 mutation, WT1 is mutated in other cancers, including acute myeloid leukaemia. Much is still to be determined in WT1 biology. The next decade will see at least three streams of attention. The first two, elucidation of the role of WT1 in RNA metabolism and the characterisation of further protein partners, may together explain the distinct tissue-specific functions of WT1. Finally, further research into the role of WT1 in haematopoiesis will improve our understanding of WT1 in leukaemia.

Evidence for a prostate cancer susceptibility locus on the X chromosome

Over 200,000 new prostate cancer cases are diagnosed in the United States each year, accounting for more than 35% of all cancer cases affecting men, and resulting in 40,000 deaths annually. Attempts to characterize genes predisposing to prostate cancer have been hampered by a high phenocopy rate, the late age of onset of the disease and, in the absence of distinguishing clinical features, the inability to stratify patients into subgroups relative to suspected genetic locus heterogeneity. We previously performed a genome-wide search for hereditary prostate cancer (HPC) genes, finding evidence of a prostate cancer susceptibility locus on chromosome 1 (termed HPC1; ref. 2). Here we present evidence for the location of a second prostate cancer susceptibility gene, which by heterogeneity estimates accounts for approximately 16% of HPC cases. This HPC locus resides on the X chromosome (Xq27-28), a finding consistent with results of previous population-based studies suggesting an X-linked mode of HPC inheritance. Linkage to Xq27-28 was observed in a combined study population of 360 prostate cancer families collected at four independent sites in North America, Finland and Sweden. A maximum two-point lod score of 4.60 was observed at DXS1113, theta=0.26, in the combined data set. Parametric multipoint and non-parametric analyses provided results consistent with the two-point analysis. Significant evidence for genetic locus heterogeneity was observed, with similar estimates of the proportion of linked families in each separate family collection. Genetic mapping of the locus represents an important initial step in the identification of an X-linked gene implicated in the aetiology of HPC.

Belgian doctors' attitudes on the management of patients in persistent vegetative state (PVS): ethical and regulatory aspects

BACKGROUND

The best care and management of patients in persistent vegetative state (PVS) has been the subject of sustained moral and legal debate for a number of years. However, the views of specialist doctors in Belgium involved in the care for patients in PVS are largely unknown.

METHODS

A postal questionnaire was sent to 403 members of Belgian Societies of Neurosurgeons, Neurologists and Rehabilitation Doctors. Their views were sought on various aspects of the management and care of PVS, focusing on the issue of the appropriateness of non-treatment and the withdrawal of artificial feeding.

FINDINGS

Of the 208 doctors who completed the questionnaires (52%), 172 (83%) indicated that they had been involved in the management of a patient in PVS. 88% of the responding doctors thought it was sometimes appropriate not to treat acute infections or other life-threatening conditions in a PVS patient. Fifty-six percent considered it sometimes appropriate to withdraw artificial feeding. About three-quarter of physicians who considered both treatment-limiting decisions appropriate thought that such decisions could be considered within the first year of the patient being in PVS. Forty percent accorded a decisive influence to an advance directive and only a small number of doctors considered the influence of the patient's family in the decision to withdraw artificial feeding as decisive. Over 80% of the clinicians disagreed with the view that each decision about withdrawing artificial nutrition and hydration (ANH) should come before the courts.

INTERPRETATION

Doctors in Belgium seem to be more reluctant to withdraw artificial feeding than not to treat acute infections or other life-threatening conditions in PVS. The reason for this difference appeared to be connected with the moral as well as with the clinical content of the decision. The broad variety of answers on the interval when the vegetative state is to be regarded as permanent and when treatment-limiting decisions are appropriate, could be due to the lack of official guidelines in Belgium. There seems however to be no consensus about a future policy in Belgium for making decisions about the withdrawal of ANH.

Numerical evaluation of the production of radionuclides in a nuclear reactor (Part II)

A computer program called LAURA has been developed to predict the production rates of any member of a nuclei network undergoing spontaneous decay and/or induced neutron transformation in a nuclear reactor. The theoretical bases for the development of LAURA were discussed in Part I. In particular, in Part I, we described how an expression based on the Rubinson (1949) approach is used to evaluate the depletion function. In this paper (Part II), we describe the full simulation of radionuclide production including the decomposition of a reaction network into independent linear chains, provisions for periodic reactor shutdown and restart, and implementation of an approximate solution given by Raykin and Shlyakhter (1989) to account for the effect of feedback due to alpha decay. Also included are some examples which demonstrate possible uses for LAURA.

Numerical evaluation of the production of radionuclides in a nuclear reactor (Part I)

Numerical evaluation of nuclear transmutations is essential for optimization of radionuclide production. Accordingly, we have developed a generalized computer program called LAURA for predicting the production rates of radionuclides in a nuclear reactor. The program is generalized in the sense that it can be used for calculation of the production rate of any member of a network undergoing spontaneous decay and/or induced neutron transformation in a nuclear reactor. In this paper (Part I), we describe the mathematical basis for the development of LAURA. Expressions based on the Rubinson (1949) approach have been used for the evaluation of the depletion functions. This method is also valid when some of the depletion constants have identical values; thus, the approximate solution of Raykin and Shlyakhter (1989) can be used to account for the effects of feedback due to alpha decay.

The effect of finasteride on the risk of acute urinary retention and the need for surgical treatment among men with benign prostatic hyperplasia. Finasteride Long-Term Efficacy and Safety Study Group

BACKGROUND

Finasteride is known to improve urinary symptoms in men with benign prostatic hyperplasia, but the extent to which the benefit is sustained and whether finasteride reduces the incidence of related events, including the need for surgery and the development of acute urinary retention, is not known.

METHODS

In this double-blind, randomized, placebo-controlled trial, we studied 3040 men with moderate-to-severe urinary symptoms and enlarged prostate glands who were treated daily with 5 mg of finasteride or placebo for four years. Symptom scores (on a scale of 1 to 34), urinary flow rates, and the occurrence of outcome events were assessed every four months in 3016 men. Prostate volume was measured in a subgroup of the men. Complete data on outcomes were available for 2760 men.

RESULTS

During the four-year study period, 152 of the 1503 men in the placebo group (10 percent) and 69 of the 1513 men in the finasteride group (5 percent) underwent surgery for benign prostatic hyperplasia (reduction in risk with finasteride, 55 percent; 95 percent confidence interval, 41 to 65 percent). Acute urinary retention developed in 99 men (7 percent) in the placebo group and 42 men (3 percent) in the finasteride group (reduction in risk with finasteride, 57 percent; 95 percent confidence interval, 40 to 69 percent). Among the men who completed the study, the mean decreases in the symptom score were 3.3 in the finasteride group and 1.3 in the placebo group (P<0.001). Treatment with finasteride also significantly improved urinary flow rates and reduced prostate volume (P<0.001).

CONCLUSIONS

Among men with symptoms of urinary obstruction and prostatic enlargement, treatment with finasteride for four years reduces symptoms and prostate volume, increases the urinary flow rate, and reduces the risk of surgery and acute urinary retention.

Heredity and prostate cancer: a study of World War II veteran twins

BACKGROUND

Increased risk of prostate cancer among men with a family history of the disease has been observed in several epidemiological studies, and family studies have identified hereditary prostate cancer characterized by early onset and autosomal dominant inheritance.

METHODS

In this study, we examine prostate cancer heritability among twins in the NAS-NRC Twin Registry, with cases ascertained from a number of sources: recent telephone interviews, Medicare and Department of Veterans Affairs hospitalizations, previous mail questionnaires, and death certificates. A total of 1,009 prostate cancer cases were identified among the cohort of 31,848 veteran twins born in the years 1917-1927.

RESULTS

Probandwise concordance for prostate cancer was substantially higher among monozygous twin pairs, 27.1%, than among dizygous twin pairs, 7.1% (P < 0.001).

CONCLUSIONS

These data suggest that genetic influences account for approximately 57%, and environmental influences for 43%, of the variability in twin liability for prostate cancer.

The use of biothesiometry to detect neuropathy in children and adolescents with IDDM

OBJECTIVE

To develop clinically useful reference ranges for vibration perception thresholds (VPTs), using biothesiometry in children and adolescents and to assess the reliability of the technique to identify subclinical neuropathy in subjects with IDDM at this age and to examine a large population-based sample of pediatric patients.

RESEARCH DESIGN AND METHODS

VPTs were measured using a handheld biothesiometer at the medial malleolus and hallux in 232 nondiabetic children and adolescents aged 7-18 years (12.9 +/- 4.2 years) and a population-based sample of 307 young IDDM patients (13.3 +/- 4.6 years of age). The mean of three readings at each site was correlated with height, pubertal status, and age for all subjects and, in addition for the IDDM sample, with the duration of IDDM, ambient blood glucose, and mean HbA1c from diagnosis. Those IDDM subjects found to have elevated VPTs (> 97th percentile), and a control group of patients with IDDM underwent nerve conduction studies to determine the sensitivity and specificity of biothesiometry to detect abnormal neural function in children. Interoperator reliability was assessed in a separate trial in which two operators measured VPTs independently in the same 11 children.

RESULTS

In the nondiabetic control subjects, height demonstrated the best correlation with VPT measures, and a reference range was thus established with percentile charts, using mean VPT and height. VPTs were higher in the diabetic sample, compared with the nondiabetic sample (P < 0.05). Of the children, 28 (9.1%) had VPT values > 97th percentile developed from studies of the nondiabetic subjects; of these, 11 were younger than 11 years and 8 were prepubertal. Nerve conduction studies confirmed reduced conduction velocity and prolonged distal latencies in those with abnormal VPTs, compared with normal control subjects and IDDM patients with normal VPTs. Sensitivity of biothesiometry to reflect abnormal nerve function was estimated as 82% and specificity as 75% at this age. Interoperator variation was small (7.25% of total variance).

CONCLUSIONS

Biothesiometry is a useful noninvasive tool for the detection of subclinical neuropathy in children and adolescents. The use of height-related reference ranges may make screening for neuropathy more feasible in younger patients and allow large-scale longitudiral analysis of its development.

Lesion size is a factor for determining the rate of port-wine stain clearing following pulsed dye laser treatment in adults

Seventy-four adult patients with facial, truncal, and extremity port-wine stains (PWS) were treated with the flashlamp-pumped pulsed dye laser (PDL) with laser output ranging from 6.0 to 7.5 J/cm2. Response to treatment was analyzed by comparing the area of involvement following each treatment with the area of involvement measured in the first treatment session. All the PWS responded with 25 to 90 percent lightening, and 85.1 percent of patients achieved 25 percent clearing. However, only 36.5 percent achieved 50 percent clearing, and none of the patients achieved 100 percent clearing. None of four patients with PWS greater than 100 cm2 achieved 50 percent clearing following a mean of 17.2 +/- 5.7 treatments. These data emphasize the importance of objectively documenting clinical response to PDL treatment of PWS. Adult patients need to be made aware that complete clearing may not be obtainable by PDL treatment alone. This is especially important for adult patients with PWS larger than 100 cm2.

Pulsatile urea excretion in the toadfish (Opsanus beta) is due to a pulsatile excretion mechanism, not a pulsatile production mechanism

When subjected to a crowding/confinement protocol in the laboratory, toadfish become facultatively ureotelic, excreting approximately 90 % of their nitrogenous waste as urea-nitrogen (urea-N). The great majority of this excretion occurs via large, irregular pulses from the head region which occur on average once per day, with a duration of 3 h or less. Pulses measured chemically by the appearance of urea-N in the external water were identical to those measured by assaying [14C]urea appearance in the water from the blood plasma. Individual toadfish maintained plasma urea concentrations over widely differing ranges (6600&shy;39 890 &micro;mol-N l-1). However, independent of absolute levels, both [14C]urea and total urea were distributed at ratios close to unity between the blood plasma and the water compartments of liver and white muscle. At times of pulsatile excretion, plasma urea concentration fell sharply. These decreases, distributed throughout the tissues of the whole body, closely matched the sizes of the measured excretion pulses. Between pulses, plasma urea concentration increased steadily at a much slower rate; the rate of rise, when distributed throughout the tissues of the whole body, corresponded to the time-averaged excretion rate over the whole day. Infusion of a typical pulse amount of urea immediately after the end of a natural pulse event raised plasma urea concentration slightly above the pre-pulse level, but did not induce another pulse event. Plasma cortisol levels declined by approximately 60 % over the 4 h period prior to a natural pulse event and then rose quickly again once the pulse had occurred. These results indicate that urea pulses are due to activation of an excretion mechanism that rapidly clears urea from the blood plasma, thereby lowering stores throughout the whole body. Metabolic production of urea is continuous and is not responsible for pulsatile excretion. The pulse event is not triggered by a specific plasma urea threshold, but may involve the hypothalamo&shy;interrenal axis.

Bioethics for clinicians: 1. Consent

Patients are entitled to make decisions about their medical care and to be given relevant information on which to base such decisions. The physicians obligation to obtain the patient's consent to treatment is grounded in the ethical principles of patient autonomy and respect for persons and is affirmed by Canadian law and professional policy. A large body of research supports the view that the process of obtaining consent can improve patient satisfaction and compliance and, ultimately, health outcomes. An exception to the requirement to obtain consent is the emergency treatment of incapable persons, provided there is no reason to believe that the treatment would be contrary to the person's wishes if he or she were capable.

Survey of British clinicians' views on management of patients in persistent vegetative state

BACKGROUND

The best care and management of patients in persistent vegetative state (PVS) has been the subject of sustained moral and legal debate for a number of years. However, the views of clinicians in the UK involved in caring for patients in PVS are largely unknown.

METHODS

A postal questionnaire was sent to 1882 consultant members of the British Association of Orthopaedic Surgeons, the Association of British Neurologists, the Society of British Neurosurgeons, and the British Society of Rehabilitation Medicine. Their views were sought on various aspects of the management and care of PVS, in particular the appropriateness of a decision not to treat and a decision to withdraw artificial nutrition and hydration (ANH).

FINDINGS

1027 doctors responded (55%) of whom 558 (54%) had experience of managing patients in PVS. Over 90% of responding doctors considered that it could be appropriate not to treat acute infections and other life-threatening conditions. 65% of doctors considered that withdrawal of ANH could be appropriate. About two-thirds of doctors who thought treatment-limiting decisions could be appropriate thought that such decisions could be considered with the first 12 months of the patient being in PVS. Despite recent case law, less than half the doctors responding to the survey thought that an advance directive made by the patient should have a decisive influence in determining treatment-limiting decisions. Most doctors would like decisions about withdrawing ANH to be made in conjunction with family members and in accordance with agreed guidelines but without the need to go to court.

INTERPRETATION

There is a broad consensus among doctors that treatment-limiting decisions are sometimes appropriate for patients in PVS, irrespective of whether they have experience of the condition or of the specialty to which they belong. However, two thirds of doctors said that such decisions can be considered at a time earlier than that recommended by the British Medical Association. It is not clear why some doctors thought a decision not to treat could be appropriate while a decision to withdraw ANH would not be.

Candida albicans induces selective expansion of human T lymphocytes expressing the T-cell receptor variable region V beta 5.1

Candida albicans is a common pathogen which can present major problems as an opportunistic skin pathogen in patients with immunodeficiency. The exact nature of the T cell responses to C. albicans is poorly understood. The purpose of this study was to determine whether C. albicans could stimulate the selective expansion of T lymphocytes expressing particular V beta gene segments. Human T lymphocytes stimulated in vitro with an extract of C. albicans were analyzed for T cell receptor V beta gene expression by using a quantitative PCR technique. We found that stimulation of peripheral blood mononuclear cells (PBMC) produced a selective increase in the expression of V beta 5.1 and 5.2 gene transcripts. Using cytofluorographic analysis with available anti-V beta monoclonal antibodies, we verified that there was a significant selective expansion (P = 0.035) of V beta 5.1 positive T lymphocytes in PBMC from six subjects stimulated in vitro with C. albicans. PCR analysis of V beta 5.1 expansion in 10 subjects showed increases in V beta 5.1 gene transcripts in 7/10 subjects. More importantly, analysis of the T cell infiltrate 48 h after intradermal injections with C. albicans also showed significant expression of V beta 5.1 in the infiltrates, along with the infiltration of V beta 8.1 + T cells. The selective expansion of V beta 5.1 bearing T lymphocytes in PBMC stimulated with C. albicans and in skin test reactions to C. albicans suggests that a restricted population of T cells react to C. albicans. Furthermore, our present data raise the provocative possibility that one or more antigens in C. albicans can act as a superantigen, producing selective expansion of a population of T lymphocytes bearing a particular V beta specificity.

Cross-national comparisons of ageing mothers of adults with intellectual disabilities

Ageing (55+ years) mothers of adults with intellectual disabilities in the Republic of Ireland, Northern Ireland and the United States were compared with respect to three general issues. Firstly, to what extent do the adults in these three countries differ in their level of reliance on their mothers? Secondly, do the mothers differ in the extent to which they have made plans for the future care of their son or daughter with intellectual disabilities? Thirdly, do the mothers differ in physical, social and psychological well-being? These cross-national comparisons were undertaken to examine the extent to which lifelong caregiving has either a common influence on mothers across national boundaries, or, alternatively, whether the cultural context exerts a unique influence on mothers in each country. Findings supported the latter explanation, even when background characteristics were statistically controlled.

Comparative study of DNA adducts levels in white sucker fish (Catostomus commersoni) from the basin of the St. Lawrence River (Canada)

The levels of DNA adducts in the hepatic tissue of the white sucker fish species Catostomus commersoni were determined by 32P-postlabelling. The fish were caught at four sites: two sites near the city of Windsor (Québec, Canada) on the St. François River, a downstream tributary of the St. Lawrence River, and two sites in the St. Lawrence River itself, near the city of Montréal (Québec, Canada). The latter sites are known to be contaminated by many pollutants including polycyclic aromatic hydrocarbons. Total adduct levels in all fish ranged from 25.1-178.0 adducts per 10(9) nucleotides. White sucker from the selected sites of the St. Lawrence River had a significantly higher mean level of DNA adducts than those of the St. François River (129.4 vs 56.8, respectively). These results suggest that the effluents of many heavy industries (e.g. from a Soderberg aluminium plant) flowing in the St. Lawrence River are more likely to produce genotoxic damage to fish than those released in one of its tributary, and mainly associated to the activities of a small town and a nearby pulp and paper mill.

Effects of feeding and confinement on nitrogen metabolism and excretion in the gulf toadfish Opsanus beta

In order to elucidate further the cues for, and the biochemical mechanisms of, the transition to ureogenesis in the gulf toadfish Opsanus beta, experiments on the effects of feeding (i.e. nitrogen loading) were carried out. Baseline nitrogen excretion rates were first measured on solitary toadfish in large water volumes (i.e. unconfined conditions). These nitrogen excretion rates were higher, and had a higher proportion as ammonia (61 %), than previously published 'control' measurements. Feeding of unconfined toadfish elevated total nitrogen excretion approximately threefold, with little change in the proportion of urea versus ammonia. During the first 24 h of confinement of unfed toadfish, absolute levels of urea excretion remained constant while ammonia excretion rates fell to near zero, so that toadfish became 90 % ureotelic. When fed prior to confinement, urea excretion rates remained constant for the first 24 h, and the bulk of the nitrogen was excreted as ammonia (80 %); excretion of the excess dietary nitrogen took up to 48 h to complete. If pre-adapted to confinement and then fed, toadfish excreted only about 55 % of their nitrogenous waste as ammonia, and excretion of excess dietary nitrogen was completed by 24 h. Elevations of hepatic glutamine synthetase (GNS) activities accompanied confinement and were shown to be almost exclusively in the cytosolic compartment and to be correlated with a decrease in the ratio of hepatic levels of glutamate:glutamine. These GNS activity increases also appear to account in part for the decrease in the percentage of ammoniotely in toadfish under conditions of nitrogen loading after confinement. However, additional means of regulating total nitrogen excretion (e.g. changes in protein turnover rates) and the degree of ureogenesis versus ammoniogenesis (e.g. N-acetylglutamate stimulation of carbamoylphosphate synthetase) must be postulated to account fully for changes in nitrogen excretion rates and activation of ureogenesis under some circumstances.

Macrophage colony-stimulating factor complementary DNA: a candidate for gene therapy in metastatic melanoma

BACKGROUND

At present, there is no highly effective treatment for metastatic melanoma. Innovative approaches aimed at inducing a more effective immune response against tumors have shown promising results in animal models. One approach involves the genetic modification of tumor cells so that they produce cytokines that stimulate an immune response.

PURPOSE

The aim of this study was to determine the effectiveness of cytokine gene therapy for metastatic melanoma in a murine melanoma model.

METHODS

B16F10 murine melanoma cells, which readily metastasize to the lungs, were transduced with a retroviral vector containing genes encoding neomycin resistance and human macrophage colony-stimulating factor (M-CSF). The presence of M-CSF messenger RNA in transduced cells was examined by coupled reverse transcription and polymerase chain reaction. Concentrations of soluble M-CSF in cell culture supernatants were determined by enzyme-linked immunosorbent assays (ELISAs). A clonal cell line, designated N+/CSF+, that expressed and secreted M-CSF was identified. Another clonal cell line, designated N+/CSF-, did not secrete M-CSF at levels detectable by ELISA. B16F10, N+/CSF-, and N+/CSF+ cells, individually or in combination, were injected intravenously or subcutaneously into C57BL/6 mice; we then evaluated the tumorigenicity and metastatic behavior of the cells, as well as the immune responses and survival of the mice. The immune responses assayed were the cytotoxic T lymphocyte (CTL) and peritoneal exudate cell (PEC) tumoricidal activities.

RESULTS

Injection of B16F10 cells into the tail vein of C57BL/6 mice led to the establishment of lung metastases by week 2 and death by week 8. Injection of the N+/CSF+ or N+/CSF- cells led to the establishment of lung metastases that were detected at 2 and 3 weeks, respectively; however, these metastatic lesions were eliminated, and the animals had survival rates similar to those of the noninjected control mice. Injection of mice with a mixture of B16F10 and N+/CSF- cells resulted in the development of metastatic disease and 0% survival at 8 weeks, whereas mice that had been given an injection of a mixture of B16F10 and N+/CSF+ cells had an 80% survival rate at 8 weeks and survived at least two times longer (P = .007). The CTL and PEC tumoricidal activities in animals given an injection of N+/CSF+ cells suggested that monocytes and lymphocytes were responsible for the observed antitumor response.

CONCLUSION

These findings suggest that the expression of M-CSF by genetically modified melanoma cells caused an effective antitumor immune response in host C57BL/6 mice and, thus, prolonged survival over that observed in the control mice.

Subcellular localization and biochemical properties of the enzymes of carbamoyl phosphate and urea synthesis in the batrachoidid fishes Opsanus beta, Opsanus tau and Porichthys notatus

The subcellular localization and biochemical properties of the enzymes of carbamoyl phosphate and urea synthesis were examined in three representatives of fishes of the family Batrachoididae, the gulf toadfish (Opsanus beta), the oyster toadfish (Opsanus tau) and the plainfin midshipman (Porichthys notatus). The primary objective of the study was to compare the biochemical characteristics of these fishes, which represent a range between ammoniotelism and ureotelism (O. beta being facultatively ureotelic), with previous patterns observed for an ammoniotelic teleost (Micropterus salmoides, the largemouth bass) and an obligate ureogenic elasmobranch (Squalus acanthias, the dogfish shark). The present study documents the expression of mitochondrial carbamoyl phosphate synthetase (CPSase) III and cytosolic CPSase II (and its associated enzymes of pyrimidine synthesis, dihydro-orotase and aspartate carbamoyltransferase) in the livers of all three batrachoidid species. Both mitochondrial and cytosolic activities of arginase were present in the livers of all three species, as were cytosolic glutamine synthetase and argininosuccinate synthetase and lyase. However, O. beta also showed mitochondrial glutamine synthetase activity and higher total hepatic levels of glutamine synthetase than either O. tau or P. notatus. Taken together, these observations confirm that the arrangement of these enzymes in the batrachoidid fishes has greater similarity to that of M. salmoides than to that of S. acanthias. However, differences within the family appear to coincide with the different nitrogen excretion strategies. O. tau and P. notatus are primarily ammoniotelic and most closely resemble the ammoniotelic M. salmoides, whereas ureotelism in O. beta is correlated with the presence of a mitochondrial glutamine synthetase and the ability to induce higher total glutamine synthetase activities than O. tau or P. notatus. Additionally, isolated mitochondria from O. beta were able to generate citrulline from glutamine, whereas those from O. tau were not. Also in contrast to S. acanthias, glutamine synthetase activities in the mitochondria of O. beta are consistently lower than those of CPSase III. This and other kinetic observations lend support to the hypothesis that glutamine synthetase may be an important regulatory control point in determining rates of ureogenesis in O. beta.

Isolation of genomic DNA from the earthworm species Eisenia fetida

Our interest in detecting genotoxic exposure in earthworms led us to isolate high quality DNA from the Eisenia fetida species. For that, we compared a modification of the conventional phenol-chloroform extraction procedure, usually referred to as the Maniatis procedure, to two commercially available kits reportedly eliminating multiple partitions in phenol and chloroform, namely the Qiagen and Nucleon protocols. From the 260 nm optical density values, the commercial kits extracts hinted toward higher DNA recovery with those procedures. However, the 260/280 nm ratios indicated that the quality of the DNA isolated with the modified Maniatis procedure was purer than that isolated with the commercial kits, the latter being most probably contaminated by proteins and/or RNA. The Maniatis procedure was slightly modified by the introduction of a potassium acetate step for protein precipitation and by shortening the proteinase K treatment from 12-18 h to only 2 h. The higher quality of the DNA isolated by phenol-chloroform extraction was confirmed by quantification with the fluorescent 3,5-diaminobenzoic acid assay. Preliminary results suggest that the modified Maniatis procedure herein described is not only applicable for DNA adducts studies using 32P-postlabelling techniques but is also suitable for DNA extraction from other earthworm species such as Lumbricus terrestris.

Pulsatile urea excretion in the ureagenic toadfish Opsanus beta: an analysis of rates and routes

This study focused on the rates and routes of urea-N and ammonia-N excretion in the ureagenic toadfish and on the possibility that urea-N excretion occurs in pulses. Experimental approaches included the following: confinement in small individual containers with automated hourly sampling of water to follow temporal excretion patterns; divided chambers to separate excretion from the anterior and posterior parts of the fish; collection of urine and rectal fluid via chronic indwelling catheters; and gavage with [14C]-labelled polyethylene glycol 4000 to detect regurgitation of gastrointestinal fluids. When a standardized 'crowding' pre-treatment was employed to induce ureotelic behaviour, the fish exhibited significant elevations in the activity of glutamine synthetase in liver, kidney and gills, elevated plasma and bile urea-N levels, but unchanged ammonia-N and urea-N levels in most other body fluids. Unencumbered ureotelic fish confined in small containers excreted 82 % of their waste-N as urea-N and 18 % as ammonia-N; almost all (94 %) of this urea-N excretion occurred in a single pulse of less than 3 h duration about once every 24 h. This daily pulse did not occur by regurgitation of gut fluids, by excretion through prominent pores behind the pectoral fins or by discharge of rectal fluid or urine. Intestinal and urinary excretion accounted for less than 10 % of whole-body urea-N excretion and a negligible fraction of ammonia-N excretion. Pulsatile urea-N excretion occurred at the head end across the gills and/or body surface. Ammonia-N excretion, which was not pulsatile, also occurred largely through the head end. However, once the toadfish had been placed in divided chambers, urea-N excretion became continuous rather than pulsatile, and ammonia-N excretion increased greatly. A severe stress response was indicated by high levels of plasma cortisol, and the skin, which lacks scales, became a significant route of both ammonia-N and urea-N excretion. We speculate that the normal adaptive significance is that ureotelism facilitates cryptic behaviour, allowing the toadfish to virtually eliminate N-waste excretion during long periods while it remains sheltered in burrows. However, during severe stress, the effects of extremely high cortisol levels overwhelm the ammonia and urea retention mechanisms, and both substances leak across the general body surface.

UREA TRANSPORT BY HEPATOCYTES AND RED BLOOD CELLS OF SELECTED ELASMOBRANCH AND TELEOST FISHES

Although urea transport is receiving increased attention in mammalian systems, very little is known about urea transport in fish tissues. This study examined mechanisms of urea transport in red blood cells and hepatocytes from the lesser spotted dogfish (Scyliorhinus canicula), Atlantic stingray (Dasyatis sabina), turbot (Scopthalmus maximus), redfish (Scianops ocellatus), gulf toadfish (Opsanus beta) and oyster toadfish (Opsanus tau). Urea appeared to be passively distributed in both tissues (i.e. there was no difference between plasma and tissue urea concentrations). Additionally, a number of in vitro experiments examining [14C]urea flux were performed. In red blood cells from all species except redfish, urea transport occurred via simple passive diffusion, but redfish red blood cells showed a small (25 %) phloretin-sensitive uptake component. In hepatocytes of the two elasmobranch species (dogfish and stingray), urea efflux was also by simple passive diffusion. However, urea efflux in toadfish (both O. beta and O. tau) hepatocytes exhibited a marked phloretin-sensitivity, and O. beta hepatocytes were used in further experiments with other inhibitors and treatments. Urea transport in O. beta had a relatively high specificity for urea compared with the urea analogues acetamide, thiourea and N-methylurea, was unaffected by phloridzin and extracellular Na+ removal, and was not inhibited by physiological levels of glucose (0.5&shy;10 mmol l-1). A phloretin-sensitive glucose transport, that was not inhibited by physiological levels of urea, was discovered in O. beta hepatocytes. The results are discussed in terms of patterns of species distribution and similarities between urea and glucose transport.

EFFECTS OF CONFINEMENT/CROWDING ON UREOGENESIS IN THE GULF TOADFISH OPSANUS BETA

In order to elucidate the cues for, and the biochemical mechanisms of, the transition to ureogenesis in the gulf toadfish Opsanus beta, experiments on the effects of confinement/crowding were carried out. Confinement of toadfish to small volumes of water initiated a switch to nearly complete reliance on ureogenesis for nitrogen excretion within 24&shy;48 h. Further experiments suggested that this switch was probably due to the physical confinement per se, rather than to a measurable build-up of ammonia in the water. However, the possibility of the response being triggered by a very low concentration of a pheromone-like substance was not excluded by our experimental design. The activities of several enzymes of ureogenesis, ornithine&shy;citrulline transcarbamoylase, aspartate amino transferase and glutamine synthetase, increased in the liver of toadfish during confinement. Notably, glutamine synthetase activity increased almost fourfold within 24 h, and this increase preceded increases in urea excretion. A number of plasma and liver amino acid concentrations changed during confinement: there were declines in plasma asparagine, glutamate and glycine levels and an increase in plasma valine, as well as a decline in liver alanine and an increase in liver arginine concentrations. Liver glutamine was not detectable. When the amino acid data are taken together with the enzyme activity changes, it appears that the switch to ureogenesis occurs primarily upstream of the ornithine&shy;urea cycle, at the level of supply of nitrogen to the pathway. The results are discussed in the context of the habitat of toadfish.

UREA PRODUCTION, ACID-BASE REGULATION AND THEIR INTERACTIONS IN THE LAKE MAGADI TILAPIA, A UNIQUE TELEOST ADAPTED TO A HIGHLY ALKALINE ENVIRONMENT

The Lake Magadi tilapia, Oreochromis alcalicus grahami, thrives in highly alkaline geothermal springs and pools surrounding Lake Magadi, Kenya (control pH=9.9, CCO2=173 mmol l-1), has a functional hepatic ornithine&shy;urea cycle (OUC) and excretes all nitrogenous waste as urea-N at variable rates (JUrea) related to O2 consumption (M&middot;O2). The mean value of JUrea/M&middot;O2 (N/O2=0.183) was high for fish but below the theoretical maximum (approximately 0.27) for 100 % aerobic respiration of protein, so an exogenous source of substrates is not required to explain the observed JUrea. JUrea was insensitive to thiourea. Urea excretion occurred largely (80 %) through the gills, but urea-N was also present in bile and urine. Control blood pHe, pHi and [HCO3-] (approximately 8.1, 7.6 and 15 mmol l-1, respectively, at approximately 32&deg;C) were extremely high. When fish were exposed to lake water titrated with HCl and aerated to remove CO2, N/O2 progressively declined. At a lake water pH of 7.05 and CCO2 of 0 mmol l-1, N/O2 was reduced by 80 % and an intense metabolic acidosis occurred (pHe=7.04, [HCO3-]=1.5 mmol l-1). Restoration of control water pH 9.9 at a CCO2 of 0 mmol l-1 resulted in intermediate levels of N/O2 and internal acid&shy;base status. Additional experiments confirmed that urea production was inhibited by low pHe, was dependent on blood [HCO3-] with a Km of 3.06 mmol l-1 and was insensitive to acetazolamide. While metabolic acidosis clearly inhibited OUC ureagenesis, the system appeared to be saturated with HCO3- under control conditions so that additional basic equivalent loading would not stimulate ureagenesis. Urea production in the Lake Magadi tilapia does not appear to remove exogenous HCO3- or to play a role in normal acid&shy;base regulation.

Effect of finasteride on prostate-specific antigen density

OBJECTIVE

Prostate-specific antigen density (PSAD) has been proposed as a diagnostic marker for prostate cancer. Because treatment with finasteride may affect PSAD differently in men with BPH compared with men with BPH plus prostate cancer, we evaluated the diagnostic utility of PSAD in men treated with finasteride for twelve months.

METHODS

Data for this analysis were obtained from 895 men with BPH enrolled in a twelve-month placebo-controlled North American study. Prostate volume was measured by magnetic resonance imaging and PSA was measured by the Hybritech immunoradiometric assay.

RESULTS

Treatment with finasteride for twelve months increased the positive predictive value of PSAD for identifying the presence of prostate cancer from 14 percent to 30 percent. Using PSA values alone with a cutoff of 10 ng/mL at baseline and 5 ng/mL after twelve months of treatment, similar specificity and sensitivity could be achieved.

CONCLUSION

The data suggest that adjustment of PSA values during treatment with finasteride can be used to maintain the diagnostic accuracy for prostate cancer while PSAD can be used to provide additional reassurance without requiring adjustment for treatment.

Assessment of ketorolac as an adjuvant to fentanyl patient-controlled epidural analgesia after radical retropubic prostatectomy

BACKGROUND

Opioids, although effective postoperative analgesics, are associated with undesirable side effects. In an attempt to determine whether adjuvant, nonopioid medication would permit a reduction of the amount of fentanyl required for postoperative analgesia, the efficacy of ketorolac, an injectable nonsteroidal antiinflammatory drug, was studied as an adjuvant to fentanyl patient-controlled epidural analgesia (PCEA) for postoperative pain management following radical retropublic prostatectomy.

METHODS

Forty patients were randomized into two groups to receive fentanyl PCEA and either ketorolac 30 mg intramuscularly every 6 h after an initial dose of 60 mg (n = 20) or placebo (n = 20) for 72 h. Visual analogue scale pain scores (0-100 mm; 0 mm = no pain; 100 mm = worst pain), sedation, fentanyl usage, gastrointestinal function, complications, blood loss, and temperature were assessed four times each day.

RESULTS

Visual analogue scale (VAS) pain scores at rest were lower in the ketorolac group during the first 4 h (P < 0.01), but were similar thereafter. Global VAS pain scores with activity were lower in the ketorolac group on postoperative day 1 (23 +/- 4 vs. 39 +/- 6; P < 0.05) and postoperative day 2 (17 +/- 3 vs. 29 +/- 4; P < 0.05). Bladder spasm pain occurred less frequently in the ketorolac group (1 vs. 9 patients; P < 0.05). Fentanyl usage was less in the ketorolac group throughout the study (33 +/- 3 vs. 50 +/- 6 micrograms/h, 0-24 h; 20 +/- 2 vs. 36 +/- 6 micrograms/h, 24-48 h; 12 +/- 2 vs. 24 +/- 6 micrograms/h, 48-72 h; P < 0.05). Sedation scores and side effects were similar, except on postoperative day 3 when nausea was less frequent in the ketorolac group (0 vs. 6 patients; P < 0.05). Recovery of gastrointestinal function occurred sooner in the ketorolac group as determined by first bowel sounds (26 +/- 3 vs. 38 +/- 4 h; P < 0.05), first clear liquids (51 +/- 2 vs. 65 +/- 3 h; P < 0.01), and first regular meal (95 +/- 4 vs. 110 +/- 4 h; P < 0.05). There was no significant difference in blood loss, transfusion requirement, hematocrit, platelet count, or temperature. There was high overall satisfaction in both groups, but fewer patients in the ketorolac group rated pain with walking as usually or always painful (1 vs. 9 patients; P < 0.05).

CONCLUSIONS

Ketorolac is a beneficial adjuvant to fentanyl PCEA for postoperative pain management after radical retropubic prostatectomy.

A potential role for superantigens in the pathogenesis of psoriasis

Psoriasis is a complex inflammatory skin disease in which local vascular changes, T-cell activation, abnormal keratinocyte proliferation and differentiation, and neutrophil activation all contribute to the ongoing disease process. Because of recent interest in T-cell activation as a trigger for psoriatic lesions, we hypothesized that psoriasis may be triggered by superantigens, e.g., toxins of microbial origin that stimulate T cells expressing particular T-cell receptor (TCR) beta chain variable (V beta) gene segments. Lesional skin biopsies and peripheral blood from two patients with acute exacerbations of their psoriasis that appeared to be triggered by infection were analyzed for TCR V beta gene expression using monoclonal antibodies directed against V beta 5.1, 5.2, 6.7, 8.1, and 12. Skin biopsies from both patients demonstrated a different pattern of V beta expansion that correspond to the V beta pattern expected to be induced by the type of superantigen expressed during the infection. In contrast, using immunofluorescence and flow cytometry, peripheral blood T cells from these patients did not demonstrate any expansion of the 5 V beta subsets studied. These observations support the hypothesis that local activation of cutaneous T cells in psoriasis may be caused by a superantigen and provides a new direction for investigating the pathogenesis of this complex and fascinating skin disorder.

Typical absence seizures in adults: clinical, EEG, video-EEG findings and diagnostic/syndromic considerations

Eighteen women and five men had typical absences. These included 10% of a consecutive hospital series of 200 adult patients with epileptic disorders. The absences began between the ages of seven and 46 years and varied in type and severity. Twenty patients also had generalised tonic-clonic seizures, ranging in frequency from one in a lifetime to one per month. Myoclonic jerks of the limbs occurred in 11 patients but were not associated with the absence attacks. Eyelid myoclonus consistently occurred with absence attacks in four patients and perioral myoclonus in two patients. Absence status occurred in five patients. Absence seizures were frequently unrecognised or misdiagnosed as complex partial seizures. Satisfactory control was achieved with sodium valproate. Electroencephalography, particularly video-electroencephalography, was invaluable in the diagnosis, but focal abnormalities in seven patients might have been erroneously interpreted as indicating partial seizures. This series showed that clinical and EEG manifestations are often syndrome-related and that there are more epileptic syndromes with typical absences than those presently recognised.

Accuracy of in-vivo assessment of prostatic volume by MRI and transrectal ultrasonography

More accurate noninvasive estimation of prostate size is important in therapeutic trials for benign prostatic hyperplasia. The accuracy of MRI and transrectal ultrasound (TRUS) in assessing prostate weight was evaluated in 48 patients who underwent radical prostatectomy for stage A or B cancer. The volume derived from the wet weight of the freshly excised specimen was used as a reference. We compared that volume with volume estimates derived from the three-axis linear dimension measurement by MRI and TRUS using a tissue density of 1.05 g/cc and the standard formula for an ellipsoid object. Prostate and seminal vesicle volumes were also computed by contouring T2-weighted 5 mm thick contiguous MR images using a semiautomatic edge detection program and pixel summation. Three-axis volume MRI method versus volume from wet weight has slightly less scatter than TRUS three-axis method (r = 0.85 vs r = 0.81). Contoured MR volume method has the least scatter r = 0.93, statistically better than the linear axis method. Contoured MRI volumetric analysis appears superior to linear MRI or TRUS methods in estimating true prostate volume.

Hearing loss--an underestimated public health problem

Estimates of hearing loss in Australia, collected over the last decade and a half, have reported a prevalence rate ranging from 0.1 to 7 per cent. This survey of a random sample of South Australians provides, depending upon definition, two estimates of 15 and 19 per cent. These data suggest that hearing loss has been underestimated as a public health problem. The need for an epidemiological study which measures actual hearing impairment, which can be used to develop an appropriate public health response, is discussed.