RhoB is expressed in migrating neural crest and endocardial cushions of the developing mouse embryo

RhoB mRNA expression was examined in the developing mouse embryo between E8.5 and E11.5. Specific expression was found in migrating neural crest (NC) cells, from the first stages of their migration at E9.5, throughout the migration period. Expression is maintained in NC derivatives for at least one embryonic day after they reach their final destinations, but is then down-regulated. RhoB is also expressed in non NC-derived neural tissues, including motor neurones and the floor plate of the neural tube. RhoB mRNA expression is also found in the developing endocardial cushions of the atrioventricular and outflow regions of the developing heart.

Comparison of 0.25% S(-)-bupivacaine with 0.25% RS-bupivacaine for epidural analgesia in labour

We have compared the efficacy of 0.25% S(-)-bupivacaine with 0.25% RS-bupivacaine in providing epidural analgesia for labour in a randomized, multicentre, double-blind study. Analgesia was initiated with 10 ml of the study solution and maintained with 10-ml top-ups. We studied 137 women and treatments were found to be equivalent for onset, duration and quality of block. Median onset of pain relief was 12 min for both drugs and median duration was 49 (range 3-129) min and 51 (7-157) min for S(-)-bupivacaine and RS bupivacaine, respectively. The estimated treatment difference for duration of pain relief was -4 (90% CI -13, 6) min. Thirty patients failed to achieve pain relief after the first injection (20 patients after S(-)-bupivacaine and 10 after RS-bupivacaine; P = 0.039). However, median duration of pain relief from the first top-up was 82 (range 3-164) min for S(-)-bupivacaine and 76 (22-221) min for RS-bupivacaine. There were no significant differences in the quality of analgesia, as assessed by the investigators. There were no significant differences in the extent of sensory block, percentage of patients with motor block or incidence of adverse events.

Perioperative dextromethorphan reduces postoperative pain after hysterectomy

We studied the effect of dextromethorphan, an N-methyl-D-aspartate antagonist, on analgesic consumption and pain scoring after abdominal hysterectomy. In this double-blinded study, 50 patients were randomized into two groups. Group DM was given oral dextromethorphan 40 mg with their premedication, then 40 mg three times per day for the next 2 days. Group P received placebo at identical times. Postoperative analgesic requirements were assessed using a patient-controlled analgesia system and subsequent oral analgesic intake using a set protocol. Pain was assessed at rest and on movement using a visual analog scale 4, 24, 48, and 72 h after the operation. Median pain scores at rest were significantly lower at 48 and 72 h and also for the sum of all resting pain scores. Mean morphine consumption was less in Group DM (1.1 vs 1.5 mg/h; P = 0.054). Usage of oral diclofenac, given every 8 h as needed, did not differ between groups, but consumption of codydramol (paracetamol 500 mg and dihydrocodeine 10 mg) was significantly less in Group DM. We conclude that the use of oral dextromethorphan has an analgesia-sparing effect and some beneficial effects on pain scoring at rest after abdominal hysterectomy.

IMPLICATIONS

Patients given dextromethorphan before and after surgery had a significant reduction in some pain scores at rest, but not on movement. There was a trend to lower morphine requirements in the first 24 h. Over the next 48 h, oral analgesic usage was significantly reduced.

Rib truncations and fusions in the Sp2H mouse reveal a role for Pax3 in specification of the ventro-lateral and posterior parts of the somite

The splotch (Pax3) mouse mutant serves as a model for developmental defects of several types, including defective migration of dermomyotomal cells to form the limb musculature. Here, we describe abnormalities of the ribs, neural arches, and acromion in Sp2H homozygous embryos, indicating a widespread dependence of lateral somite development on Pax3 function. Moreover, the intercostal and body wall muscles, derivatives of the ventrolateral myotome, are also abnormal in Sp2H homozygotes. Pax3 is expressed in the dermomyotome, but not in either the sclerotome or the myotome, raising the possibility that Pax3-dependent inductive influences from the dermomyotome are necessary for early specification of lateral sclerotome and myotome. Support for this idea comes from analysis of gene expression markers of lateral sclerotome (tenascin-C and scleraxis) and myotome (myogenin, MyoD, and Myf5). All exhibit ventrally truncated domains of expression in Sp2H homozygotes, potentially accounting for the rib and intercostal muscle truncations. In contrast, the medial sclerotomal marker Pax1 is expressed normally in mutant embryos, arguing that Pax3 is not required for development of the medial sclerotome. Most of the somitic markers show ectopic expression in anteroposterior and mediolateral dimensions, suggesting a loss of definition of somite boundaries in splotch and explaining the rib and muscle fusions. An exception is Myf5, which is not ectopically expressed in Sp2H homozygotes, consistent with the previous suggestion that Pax3 and Myf5 function in different pathways of skeletal myogenesis. PDGFalpha and its receptor are candidates for mediating signalling between myotome and sclerotome. We find that both genes are misexpressed in Sp2H embryos, suggesting that PDGFalpha/PDGFRalpha may function downstream of Pax3, accounting for the close similarities between the splotch and Patch mutant phenotypes. Our findings point to additional regulatory functions for the Pax3 transcription factor, apart from those already demonstrated for development of the neural tube, neural crest, and dermomyotome.

Drug abuse and incarcerated women. A research review

Drug abuse is the primary reason women enter prison and is the primary health problem of women in prison. There has been little research conducted specifically with this population; information must be drawn from studies with nonincarcerated addicted women and incarcerated addicted men. The purpose of this paper is to review what is known about the treatment and aftercare needs of this group (including relapse and recidivism prevention) and to propose an agenda for future research.

Molecular cloning and characterization of the rat P2Y4 receptor

Degenerate PCR was used to amplify DNAs encoding members of the P2Y receptor family from rat brain RNA. A full-length sequence obtained for one novel clone (R5) contained an intronless open reading frame that encoded a polypeptide of 361 amino acids, sharing 84% sequence identity with the human P2Y4 receptor. When R5 was stably expressed in Jurkat cells, calcium fluxes resulting from stimulation of the receptor showed that UDP, ADP, 2-methylthio-ATP, and diadenosine tetraphosphate were inactive, whereas UTP and ATP were both full agonists with similar potency. At the human receptor, ATP has significantly lower potency than UTP. The R5 transcript was not detected in brain by northern hybridization. Therefore, its tissue distribution was assessed by PCR, and the mRNA was found to be widely distributed at a low abundance, being present in brain, spinal cord, and a variety of peripheral organs. Localization of the receptor transcript in adult rat brain sections by in situ hybridization indicated that it is expressed at highest levels in the pineal gland and ventricular system. It is presumed that R5 is a species orthologue of the human P2Y4 receptor but with this significant difference in agonist pharmacology.

Versican expression is associated with chamber specification, septation, and valvulogenesis in the developing mouse heart

The versican (PG-M) gene encodes a chondroitin sulfate proteoglycan that is nonpermissive for cell migration and appears in association with slow cell proliferation and cytodifferentiation. Using the techniques of in situ hybridization and immunocytochemistry on sectioned mouse embryos, we found that the mRNA and protein for versican show similar distributions and are expressed in a dynamic pattern during development of the heart. Versican exhibits generalized expression in the tubular heart but becomes rapidly downregulated in the atrium and exhibits higher transcript levels on the right side of the ventricular chamber than the left, before the onset of ventricular septation. Versican is expressed strongly in the trabeculated ventricular myocardium, whereas the compact proliferative zone has lower transcript abundance. It is expressed in the outer layers and on the crest of the ventricular septum and is prominent on the mesenchymal cap of the primary atrial septum. Versican is particularly strongly expressed in the endocardial cushions of the atrioventricular and outflow tract regions and in the atrioventricular, semilunar, and venous valves. This study raises the possibility that versican may be involved in specification of the ventricular chambers, in growth and fusion of the atrial and ventricular septa, and in the transformation from epithelium to mesenchyme that characterizes development of the endocardial cushions. Versican may be a key participant in cardiogenesis, responding to the many diffusible signals that mediate interactions between the developing endocardium and myocardium.

Transient radicular irritation with intrathecal plain lignocaine

BACKGROUND

The aetiology of the syndrome known as transient radicular irritation (TRI) has generated much interest.

METHOD

A 50-year-old woman had right knee arthroscopy performed under spinal anaesthesia with 1% plain lignocaine.

RESULT

At home, on the night of the procedure, she was woken by severe, bilateral cramp-like pain in both buttocks radiating to her thighs. Neurological examination of her lower limbs, the next morning, was entirely normal. The pain lasted for 36 h and a full recovery was made.

CONCLUSION

This case of transient radicular irritation occurred in a patient given 40 mg of subarachnoid lignocaine (the lowest dose of isobaric preservative-free lignocaine reported thus far that has been associated with these symptoms). Her operation was performed in the supine position. The lack of confounding factors (hyperbaricity, high concentration solution, preservatives, lithotomy position) suggests lignocaine as a possible cause, yet current theories do not fully explain the aetiology of transient radicular irritation. Results from large-scale epidemiological studies will hopefully provide insight into the cause of this problem.

Over-expression of the chondroitin sulphate proteoglycan versican is associated with defective neural crest migration in the Pax3 mutant mouse (splotch)

Splotch mice, which harbour mutations in the Pax3 gene, exhibit neural crest-related abnormalities including pigmentation defects, reduced or absent dorsal root ganglia and failure of cardiac outflow tract septation in homozygotes. Although splotch neural crest cells fail to colonise target tissues, they initiate migration in vivo and appear to migrate as well as wild type neural crest cells in vitro, suggesting that the neural crest abnormality in splotch may reside not in the neural crest cells themselves, but rather in the extracellular environment through which they migrate. We have examined the expression of genes encoding extracellular matrix molecules in Sp2H homozygous embryos and find a marked over-expression of transcripts for the chondroitin sulphate proteoglycan versican in the pathways of neural crest cell migration. Use of cadherin-6 expression as a marker for neural crest demonstrates a striking correlation between up-regulation of versican expression and absence of migrating neural crest cells, both in the mesenchyme lateral to the neural tube and in the lower branchial arches of Sp2H homozygotes. Pax3 and versican have mutually exclusive expression patterns in normal embryos whereas, in Sp2H homozygotes, versican is generally over-expressed with 'infilling' in regions that would normally express functional Pax3. Versican, like other chondroitin sulphate proteoglycans, is non-permissive for migration of neural crest cells in vitro, and we suggest that over-expression of this molecule leads to the arrest of neural crest cell migration in splotch embryos. Pax3 may serve to negatively regulate versican expression during normal development, thereby guiding neural crest cells into their pathways of migration.

Development of a lethal congenital heart defect in the splotch (Pax3) mutant mouse

OBJECTIVE

The splotch (Sp2h) mutation disrupts the Pax3 gene and is lethal in homozygotes. The aim of the present study was to investigate the cause of lethality.

METHODS AND RESULTS

Using the splotch (Sp2H) mouse mutant, we demonstrated that approximately 60% of Sp2H homozygotes die in utero at 13.5-14.5 days of gestation. All these embryos have cardiac malformations involving partial or complete failure of septation of the outflow tract. Although the cause of death in utero is unknown, the dying embryos are edematous, their superior caval veins are over-expanded, and the fetal liver is enlarged and engorged with blood, all signs of cardiac failure. The remaining Sp2H homozygotes die around the time of birth, and these embryos have grossly normal hearts. All Sp2H homozygotes have neural tube defects, either spina bifida, exencephaly, or both. Although these defects clearly do not cause death in utero, they are very likely responsible for the perinatal death of homozygotes that survive to late gestation. There is no correlation between the presence or absence of a cardiac defect and the type of neural tube defect. On the other hand, there is a striking correlation between presence of a cardiac defect and reduction or absence of dorsal root ganglia, which are derivatives of the neural crest.

CONCLUSIONS

In this paper, we show that the lethality has a biphasic pattern, and the data strongly suggests that mid-gestation lethality is due to cardiac defects and not the associated neural tube defects. This finding supports the idea that 'conotruncal' cardiac defects involving the ventricular outflow tracts develop as a result of failure of the 'cardiac' neural crest to colonise the developing heart in the mid-gestation embryo, and that the resulting heart defects are solely responsible for the observed mortality.

Heterotopic transplantation as a model to study the regulation of spermatogenesis; some histomorphological considerations about sperm decline in man

A novel animal model (syngeneic neonatal testicular graft transplanted under the skin of the outer ear in adult inbred Fischer rats that had been castrated, hypophysectomised, and/or subjected to hormonal replacement therapy) was developed to study regulation of spermatogenesis and Sertoli cell number. Given that Sertoli cell number and testicular size are important in determining spermatozoan production rates, this model was first used to study Sertoli cell proliferation, testicular size, and establishment of germ cells. The specific objectives were to determine the developmental pattern of Sertoli cell numbers in transplanted testes and the effect of number of testes transplanted, sex of hosts, pituitary hormonal removal, and replacement on Sertoli cell number, hormonal status of the host, and establishment of germ cells. A few tubules had complete spermatogenesis at 90 days posttransplantation, indicating that Sertoli cells in some of these tubules were functional. Leydig cell structure appeared to be normal, but the density of these interstitial cells was greater than that in testes of intact rats. Although the weight of the seminal vesicles and prostate were maintained in the castrated host with transplants, both serum FSH and LH concentrations were higher than intact control rats. Leukocytic infiltration of testes was not observed in intact rats or in rats receiving neonatal testes. Although transplanted testes showed a delay in reaching the plateau value for Sertoli cell number per testis and although the value reached was lower than in intact testes, the developmental pattern of Sertoli cell proliferation (early division of cells followed by stabilized number of cells) in transplanted testes was similar to that in intact rats. Hypophysectomy reduced the growth of testicular grafts, and hormonal replacement via retransplantation to pituitary intact hosts enhances Sertoli cell proliferation and testicular growth. When two on four testes were transplanted into castrated males or ovariectomized female hosts for 65 days, there was no difference in the graft weights or Sertoli cell numbers between sexes of hosts. Four transplanted testes per rat produced more total testicular parenchyma and a greater number of Sertoli cells per testis than did two testes regardless of sex of the host. Transplantation of six or eight testes produced more total Sertoli cells/host than that found in testes of intact rats. Using hormonal therapy in hypophysectomized hosts, the testicular parenchymal weight was greater for pituitary-intact hosts and FSH-LH combination than the control media. There was no statistically significant difference among the media control, LH, FSH, and GH. This testicular transplant model has shown that the period of Sertoli cell proliferation can be delayed by hypophysectomy, that Sertoli cell number can be influenced by endogenous and exogenous hormones, and that a major component in regulation of testicular size is at the level of the testis. Hence, this model should facilitate study of experimental endocrine manipulation control and potential experimental intervention to increase Sertoli cell number, testicular size, and spermatogenesis. Regarding human sperm count decline in recent years, there appears to be no significant decline in Sertoli cell number or spermatogenic potential in a group of North American men. However, there was a significant decline in volume/man of Leydig cells and volume/man of Leydig cell cytoplasm.

Pax3 is required for cardiac neural crest migration in the mouse: evidence from the splotch (Sp2H) mutant

Neural crest cells originating in the occipital region of the avian embryo are known to play a vital role in formation of the septum of the cardiac outflow tract and to contribute cells to the aortic arches, thymus, thyroid and parathyroids. This ‘cardiac’ neural crest sub-population is assumed to exist in mammals, but without direct evidence. In this paper we demonstrate, using RT-PCR and in situ hybridisation, that Pax3 expression can serve as a marker of cardiac neural crest cells in the mouse embryo. Cells of this lineage were traced from the occipital neural tube, via branchial arches 3, 4 and 6, into the aortic sac and aorto-pulmonary outflow tract. Confirmation that these Pax3-positive cells are indeed cardiac neural crest is provided by experiments in which hearts were deprived of a source of colonising neural crest, by organ culture in vitro, with consequent lack of up-regulation of Pax3. Occipital neural crest cell outgrowths in vitro were also shown to express Pax3. Mutation of Pax3, as occurs in the splotch (Sp2H) mouse, results in development of conotruncal heart defects including persistent truncus arteriosus. Homozygotes also exhibit defects of the aortic arches, thymus, thyroid and parathyroids. Pax3-positive neural crest cells were found to emigrate from the occipital neural tube of Sp2H/Sp2H embryos in a relatively normal fashion, but there was a marked deficiency or absence of neural crest cells traversing branchial arches 3, 4 and 6, and entering the cardiac outflow tract. This decreased expression of Pax3 in Sp2H/Sp2H embryos was not due to down-regulation of Pax3 in neural crest cells, as use of independent neural crest markers, Hoxa-3, CrabpI, Prx1, Prx2 and c-met also revealed a deficiency of migrating cardiac neural crest cells in homozygous embryos. This work demonstrates the essential role of the cardiac neural crest in formation of the heart and great vessels in the mouse and, furthermore, shows that Pax3 function is required for the cardiac neural crest to complete its migration to the developing heart.

Transferrin and its receptor in the development of genetically determined neural tube defects in the mouse embryo

The iron-binding growth factor transferrin is taken up and localised in the hindgut of midgestation mouse embryos. We investigated whether the distribution of transferrin may be disturbed in mutant curly tail embryos, a proportion of which exhibit a cell proliferation defect affecting the hindgut endoderm, as part of the pathogenetic sequence leading to development of neural tube defects. Immunostaining revealed a reduction in the binding and/or uptake of transferrin by hindgut epithelial cells in affected curly tail embryos compared with their unaffected littermates. There was no apparent difference between the two embryo types, however, in the distribution or level of expression of the transferrin receptor. The receptor is expressed specifically in the hindgut endoderm of the 10.5-day embryo, although its mRNA is present in all tissues of the posterior neuropore region, suggesting posttranscriptional control of gene expression. These findings may indicate a role for transferrin binding and/or uptake in the regulation of cell proliferation in the hindgut endoderm, with a defect in this process in the curly tail mutant. However, an alternative explanation is suggested by our finding that transferrin immunostaining is more intense in the hindgut of unaffected curly tail embryos than in nonmutant CBA/Ca and CD-1 embryos. Thus, mutant embryos may increase their uptake of transferrin in an attempt to compensate for defective cell proliferation in the hindgut resulting from a defect in another pathway. Only a proportion of embryos are able to mount this compensatory response leading to the observed partial penetrance of developmental defects in the curly tail mutant mouse.

Does pre-incisional thoracic extradural block combined with diclofenac reduce postoperative pain after abdominal hysterectomy?

In a double-blind, randomized study, we investigated 40 patients undergoing abdominal hysterectomy; patients received 0.5% plain bupivacaine 20 ml via a low thoracic extradural catheter and a diclofenac suppository (100 mg), either 30 min before incision (group 1) or 30 min after incision (group 2). All patients received a standard general anaesthetic and no opioid was used before or during operation. Postoperative analgesic requirements were measured using a patient-controlled analgesia (PCA) system. Pain was assessed using a visual analogue scale (VAS) and a verbal pain score (VPS) on movement up to 48 h after operation. There was no significant difference in the time to first request for morphine but consumption of morphine was significantly greater in group 1 at all times except 24 h. There were no significant differences in VAS and VPS pain scores, although both scores were consistently higher in group 1. Patient satisfaction with the quality of analgesia, at 24 h, demonstrated no significant difference between the two groups. The combination of extradural block and diclofenac suppository given before operation did not appear to produce a clinically effective pre-emptive analgesic effect.

Cloning and characterisation of a bovine P2Y receptor

Using a chick P2Y1 receptor cDNA probe we have isolated a mammalian P2Y receptor clone from a bovine aortic endothelial cell library. The sequence has a high degree of similarity to the chick P2Y1 clone. When transfected into the Jurkat cell line, the cDNA conferred sensitivity to purinoceptor agonists. Using fura-2 loaded cells the potency order at the receptor was found to be 2-methylthioadenosine 5' triphosphate = adenosine 5' diphosphate > adenosine 5' triphosphate >> alpha,beta-methyleneadenosine 5' triphosphate and uridine 5' triphosphate. This corresponds to the agonist potency order expected for the bovine aortic endothelial cell P2Y receptor.

Effect of i.v. diamorphine on the regression of spinal block

Twenty patients undergoing transurethral prostatectomy under spinal anaesthesia were allocated randomly in one of two groups. After operation dermatomal levels to cold were measured every 30 min until they had receded to T10. Patients in group 1 were then given diamorphine 5 mg in 0.9% saline 5 ml i.v. and in group 2 0.9% saline 5 ml i.v. Block level to cold and degree of motor block were assessed at 15-min intervals for 1 h after injection. Block regression continued in the control group while there was no decrease in the diamorphine group for 30 min (P < 0.01) after which it then receded at a similar rate as the control group. There was no significant difference in motor block between the two groups.

Consciousness raising in participatory research: method and methodology for emancipatory nursing inquiry

Nursing practice and research that are grounded in emancipatory inquiry challenge the inequalities and injustices that affect health in this society. Increasing numbers of nurse scholars have explored the use of emancipatory inquiries (particularly feminist theory and critical theory) as philosophic bases for nursing practice and as theoretical or methodologic perspectives for nursing research. This article presents participatory research as a methodology and consciousness raising as a method for nursing research that addresses the emancipatory goals of feminist and critical theories. An example of consciousness raising in a participatory nursing research project is offered. It is argued that participatory research can produce a revolutionary emancipatory knowledge for the future of nursing and health care.

Women and illicit drugs: sexuality and crack cocaine

As part of a larger, federally funded study, the purpose of this preliminary, descriptive study was to describe the sexual feelings and sexual functioning of women who used large amounts of crack cocaine. A structured interview with questions pertaining to the effect of crack use on sexual feelings and sexual function was conducted with 100 African-American women who either were in treatment for crack abuse or were currently using the drug. The data did not support the commonly held notions that crack is an aphrodisiac for women and that crack makes women want sex. Furthermore, the women in this study had a higher level of sexual dysfunction than was found in a previous study of women who used alcohol. More research on the sexual experiences of women who use illicit drugs such as crack is needed if practitioners are to base their interventions on women's realities, not on stereotypes.