Interaction between dorsal and ventral cells in the imaginal disc directs wing development in Drosophila

The adult appendages of Drosophila develop from imaginal discs. An early step in disc patterning involves the formation of developmental boundaries that subdivide the discs into compartments. Anterior and posterior compartments are established in the embryo. Later in development a new boundary originates to subdivide the wing disc into dorsal and ventral compartments, which correspond to the dorsal and ventral surfaces of the adult wing. We report here that spatially localized expression of the homeobox gene apterous (ap) specifies the identity of dorsal cells in the wing. The boundary of cell lineage restriction between dorsal and ventral compartments coincides with the limit of the domain of ap expression. Using genetic mosaics, we show that juxtaposition of dorsal and ventral cells induces formation of the wing margin. We present evidence that the dorsal-ventral boundary promotes growth and serves as a pattern-organizing center in the wing disc.

Effects of dietary iron and folate supplementation on the physiological changes produced in weanling rats by sodium saccharin exposure

Exposure of rats to high dietary levels of sodium saccharin (NaSac) started in utero produce physiological effects at 30 days post-birth that are similar to those found in pups of iron-deficient dams. These similarities suggest that some of the changes due to NaSac are secondary to iron deficiency. The present experiment investigated whether the effects of 7.5% dietary NaSac in the newborn rat could be prevented by dietary iron and/or folate supplementation. The NaSac-related effects prevented by iron supplementation included anaemia, decreased serum iron and folate, increased serum cholesterol and triglyceride and increased serum vitamin E. Folate supplementation prevented NaSac-induced depression of serum folate and increase in serum vitamin E. Although bladder hyperplasia was increased by dietary iron and/or folate supplementation, the majority of the urinary chemistry changes associated with NaSac treatment were not affected. The results show that some physiological changes associated with NaSac treatment in the newborn rat may occur as a consequence of iron deficiency rather than a direct effect of NaSac treatment. These changes may be independent of the urinary and bladder effects, which are not reversed by iron supplementation.

Dissection of an indirect autoregulatory response of a homeotic Drosophila gene

Homeotic genes often use autoregulation as a mechanism to maintain their expression. Autoregulation of Ultrabithorax (Ubx) in the visceral mesoderm is at least partly indirect and mediated by extracellular signalling from wingless (wg) and decapentaplegic (dpp). Ubx controls the localized expression of these two extracellular proteins. Here, we identify separate wg and dpp response elements within upstream sequences of Ubx. Our evidence suggests that there are two distinct response factors each of which, after signal-induced activation, mediates transcriptional activation through its cognate element, whereas each element is recognized by a repressor in the absence of the corresponding signal. We show that the response factors and other components for transmission of the wg and, probably, of the dpp signal are present throughout the midgut mesoderm. Thus, there may be ubiquitous repression, preventing Ubx autoregulation throughout the visceral mesoderm, which is relieved locally by wg and dpp signalling. Evidently, the two signals convey positional information, allowing visceral mesoderm cells to reassess their position at advanced stages of embryogenesis and to decide whether or not to maintain expression of a homeotic gene.

Application of scanning electron microscopy and X-ray analysis to urinary tract cancer in animals and humans

Scanning electron microscopy (SEM) has proven useful in various aspects of urinary bladder carcinogenesis research and these are reviewed as they pertain to our research involving sodium saccharin in the rat. Sodium saccharin-carcinogenesis in rats requires administration at high doses beginning at birth or earlier. Administration beginning at ages of 5 weeks or later results in much lower incidences of bladder tumors. Methods were developed for examining the rat fetal and neonatal bladder to further evaluate effects at these critical ages. Several significant differences were found by SEM between the fetal bladder compared to the adult. The typical polygonal superficial cells of the bladder with asymmetric unit membrane were present before birth, but the slow turnover rate of the adult bladder did not occur until 3-4 weeks of age. Sodium saccharin causes increased proliferation rates and hyperplasia of the urothelium which is dose-dependent. SEM was found to be more sensitive than either light microscopy or labeling indices to detect the earliest lesions induced by sodium saccharin. More recently, amorphous and crystalline material in the urine of rats fed high doses of sodium saccharin were detected by SEM examinations which contained silicon as well as calcium, phosphate, and magnesium as detected by energy dispersive X-ray analysis (EDS) with the SEM. These parameters may be relevant to differences between rats and humans and pertain to extrapolations regarding risk assessment.

Distal-less is a downstream gene of Deformed required for ventral maxillary identity

The homeotic selector (HOM) proteins are required for the diversification of the anterior-posterior axis of the Drosophila body plan, assigning unique identities to regional domains of cells comprising one or a few parasegments or segments. The HOM proteins apparently accomplish this task by the transcriptional regulation of numerous downstream genes. At present few downstream genes are known, so models of how downstream genes mediate HOM functions are based more on intuition than information. Our results indicate that Distal-less is a downstream gene of the HOM gene Deformed, and Distal-less function is required for the elaboration of a subset of the maxillary epidermal identities specified by Deformed. The regulatory effect of Deformed on Distal-less is mediated by a ventral maxillary-specific enhancer located 3′ of the Distal-less transcription unit. We propose that Deformed and Distal-less, both of which encode homeodomain transcription factors that are persistently expressed in ventral maxillary cells, combinatorially specify a subsegmental code required for a group of cells to differentiate maxillary cirri.

Allocation of the thoracic imaginal primordia in the Drosophila embryo

The primordia of the thoracic imaginal discs of the Drosophila embryo originate as groups of cells spanning the parasegment boundary. We present evidence that the thoracic imaginal primordia are allocated in response to signals from the wingless (wg) and decapentaplegic (dpp) gene products. Rows of cells that express wg intersect rows of cells that express dpp to form a ladder-like pattern in the ectoderm of the germ band extended embryo. The imaginal primordia originate as groups of cells which lie near these intersection points. We have used a molecular probe derived from the Distal-less (Dll) gene to show that this population contains progenitor cells for both the dorsal (i.e. wing) and ventral (i.e. leg) discs. Although we show that Dll function is not required for allocation of imaginal cells, activation of an early Dll enhancer may serve as a molecular marker for allocation. A group of cells, which includes the imaginal progenitors, activate this enhancer in response to intercellular signals from wg and perhaps from dpp. We have used a conditional allele of wg to show that wg function is transiently required for both allocation of the imaginal primordia and for initiation of Dll expression in these cells during the brief interval when wg and dpp form the ladder-like pattern. Allocation of the imaginal primordium and activation of Dll expression appear to be parallel responses to a single set of positional cues.

Proconvulsant and anticonvulsant properties of ethanol: studies of electrographic seizures in vitro

Recent studies have demonstrated that ethanol is a potent blocker of N-methyl-D-aspartate (NMDA) receptor mediated responses. It is well known that neuroplasticity processes depend on the activation of the NMDA type of excitatory amino acid receptor. We have used an in vitro model of electrographic seizures (EGS), a neuroplasticity process, to examine the effect of varying ethanol concentrations. In the present experiment, slices of rat hippocampus were electrically stimulated to produce stimulus train-induced epileptiform bursting in area CA3. EGS duration and intensity was enhanced by 10 mM ethanol, whereas increasing the concentration of ethanol (60-300 mM) attenuated established EGSs. Ethanol also raised the threshold to elicit an EGS. Removal of low ethanol concentrations resulted in a hyperexcitable state, with increased EGS duration and intensity. These results reflect acute biphasic effects of ethanol across concentrations, and withdrawal hyperexcitability. The effects of ethanol on EGSs, at concentrations which elicit intoxication but not anesthesia (< 75 mM), resemble the actions produced by NMDA antagonists on EGSs. Therefore the effects of ethanol on stimulus train-induced EGSs may be mediated through an action at the NMDA receptor complex.

Laparoscopic colorectal resection for cancer: the Cleveland Clinic Florida experience

Since the first successful laparoscopic cholecystectomy was performed in 1987, surgeons have begun to focus their attention on more diverse procedures. The last few years have brought a tremendous amount of enthusiasm toward laparoscopic surgery, which has finally reached the colorectal surgical communities. Currently, laparoscopic bowel surgery is undergoing critical appraisal. Through meaningful prospective data retrieval, answers are being obtained to questions dealing with the efficacy and utility of this technique for colorectal diseases. Specifically, although laparoscopic colorectal surgery is feasible, one cannot definitively attest to its superiority or even equivalence to standard open laparotomy. Furthermore, it will take 5 years before we begin to collect data regarding survival rates and local recurrence for the patient with colorectal carcinoma. This article discusses the technique utilized, and our own experience with laparoscopic colorectal surgery for malignancy.

Sequencing analysis of Ha-, Ki-, and N-ras genes in rat urinary bladder tumors induced by N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) and sodium saccharin

Male F344 rats were fed N[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) for up to 4 wk, then given the basal diet with or without 5% sodium saccharin for up to 100 wk. In a previous study, we demonstrated point mutations in codons 12 and 61 of Ha-ras gene among eleven transitional cell carcinomas (TCC), one undifferentiated carcinoma, and two sarcomas of the urinary bladder (Mol Carcinogen 3:210-215, 1990). In this study, Ha-ras, Ki-ras, and N-ras sequences were examined by polymerase chain reaction (PCR) and direct DNA sequencing. The results confirm the point mutation in codon 61 (CAA to CGA in 5 TCCs and to CTA in one TCC) of the Ha-ras gene. Mutation at codon 12 was not confirmed. No mutation was found in the Ki-ras gene. Sequences of the N-ras gene exons 1 and 2 were determined, and no mutations was detected. These results suggest the involvement of activated Ha-ras gene, but not Ki-N or N-ras gene, in rat urinary bladder carcinogenesis induced by FANFT. Subsequent sodium saccharin administration did not affect the changes in Ha-ras gene.

Intraocular fluid cultures after primary pars plana vitrectomy

To determine what organisms enter the eye and remain in the eye after pars plana vitrectomy, vitreous cavity aspirates were cultured postoperatively. Two of 33 (6%) consecutive eyes undergoing primary pars plana vitrectomy had positive cultures. One sample grew a single colony of Staphylococcus epidermidis, the second grew two colonies of Acinetobacter lwoffi. Neither of these eyes developed endophthalmitis. This study demonstrates that bacteria enter the eye at a low rate during pars plana vitrectomy and that the eye on which a vitrectomy has been performed is capable of clearing a low inoculum of bacteria.

Absence of ras oncogene activation in rat urinary bladder carcinomas induced by N-methyl-N-nitrosourea or N-butyl-N-(4-hydroxybutyl)nitrosamine

Previously, we demonstrated point mutations of the H-ras gene in N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT)-induced rat urinary bladder carcinomas. In this study, ras oncogene activation was examined in urinary bladder carcinomas induced by N-(4-hydroxybutyl)nitrosamine (BBN) or N-methyl-N-nitrosourea (MNU) administration followed by uracil treatment. In the first experiment, MNU (20 mg/kg body wt) was i.p. injected into 11 male F344 rats twice a week for 4 weeks, followed by feeding 3% uracil for 20 weeks (MNU/uracil group). Ten rats were given only 3% uracil without MNU pretreatment. In the second experiment, 20 male F344 rats were given 0.05% BBN in the drinking water for 4 weeks, then fed 3% uracil for 20 weeks (BBN/uracil group). Another 20 rats were fed 3% uracil without the BBN pretreatment. Transitional cell carcinomas were induced in the urinary bladder of all rats in the MNU/uracil and BBN/uracil groups. Papillomas and hyperplasias were present in the rats given uracil without prior BBN or MNU. DNA and protein were extracted from the tumors (MNU/uracil or BBN/uracil groups) or from the scraped bladder epithelium (uracil alone groups). Sequences around codons 12, 13 and 61 of H-, K- and N-ras genes were examined by direct sequencing after polymerase chain reaction, and p21 was examined by Western blotting. No mutation was found within the examined sequences and p21 showed no changes in mobility. There was no difference in the level of p21 expression between rats treated with MNU/uracil or BBN/uracil compared to corresponding uracil alone groups. These results indicate that the ras oncogene was not activated in urinary bladder carcinomas induced by BBN or MNU in combination with uracil treatment, in contrast to previous findings with FANFT.

The effect of cyclophosphamide administration on the kidney of the rat

In studies primarily designed to evaluate the effectiveness of chitosan as a treatment for cyclophosphamide-induced hemorrhagic cystitis in the rat, renal papillary necrosis and pyelonephritis were observed. Cyclophosphamide alone produced relatively mild renal changes. The combination of cyclophosphamide and intravesical instillation of acetic acid induced renal papillary necrosis (38 to 83% incidence) along with pyelonephritis, hydroureter and hydronephrosis. Chitosan, instilled in place of acetic acid, partially inhibited the induction of renal papillary necrosis. It appears that the presence of vesico-ureteral reflux with or without associated hydroureter and hydronephrosis is a prerequisite for cyclophosphamide-induced renal damage.

Homeotic genes of the bithorax complex repress limb development in the abdomen of the Drosophila embryo through the target gene Distal-less

Homeotic genes encode transcription factors that are thought to specify segmental identity by regulating expression of subordinate genes. Limb development is repressed in the abdominal segments of the Drosophila embryo by the hometic genes of the Bithorax complex (BX-C). Localized expression of the homeobox gene Distal-less (DII) is required for leg development in thoracic segments. We have identified a minimal cis-regulatory enhancer element that directs DII expression in the larval leg primordia. We present evidence that the BX-C proteins repress DII expression in abdominal segments by binding to a small number of specific sites in this element. Mutating these sites eliminates BX-C protein binding and renders the element insensitive to BX-C-mediated repression in vivo. Repression of limb development in the abdomen appears to be controlled at the DII enhancer. Thus DII may serve as a downstream target gene through which the homeotic genes control abdominal segment identity in the Drosophila embryo.

Ras involvement in cells transformed with 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) in vitro and with N-[4-(5-nitro-2-furyl)-2-thiazoyl]formamide in vivo

N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) administration to rats followed by sodium saccharin results in transitional cell carcinomas of the bladder, of which 24% harbor an activated H-ras gene. Since 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) is the mutagenic and carcinogenic metabolite of FANFT in vivo, we wished to examine ras activation in in vitro ANFT-transformed rat bladder epithelial cells as well as four cell lines established in culture from in vivo FANFT-induced rat bladder tumors. Screening by Western blotting revealed no enhanced levels of p21ras in ANFT-transformed cells nor in cells established in culture from FANFT-induced rat bladder carcinomas. Further investigations using immunohistochemical staining with a different pan-reactive p21 monoclonal antibody (Cetus Corporation) specific for this method, however, showed two groups of cells from FANFT-induced rat bladder tumors had enhanced immunoreactivity. Apart from this, p21ras expression of most of the cells groups varied little from the controls. We examined the reported hot spots (exons 1 and 2) of each of the ras genes (H-, K- and N-ras) by direct sequencing of amplified DNA. No mutations were present. We conclude, therefore, that ANFT transformation of primary rat bladder epithelial cells in vitro may not in this case be mediated by ras activation, although this is difficult to determine since others have observed that optimal culture conditions can select for certain populations of cells without ras activation.

Epidemiology and etiology of bladder cancer

Urinary bladder cancer has long been associated with specific etiologic factors, and our knowledge of these factors has increased during this century. The most important factor, even in industrialized societies, is cigarette smoking. Specific chemicals have also been identified as causing bladder cancer, as have a variety of occupational exposures to less well-defined specific agents. In other parts of the world, the association of bladder cancer with Balkan nephropathy, endemic blackfoot disease, and schistosomiasis provides additional leads for investigating, and potentially preventing, the process of carcinogenesis in humans. Many of the critical observations in our understanding of bladder cancer have been made by practicing physicians, and this is likely to continue. It is essential that physicians dealing with bladder cancer patients be attuned to potential etiologic factors, including cigarette smoking, various industrial exposures, or drug exposures to further our understanding of this issue. Bladder cancer is a potentially preventable disease and an important one, as indicated by the total number of cases and the extent of morbidity and death attributable to it around the world.

Acrolein initiates rat urinary bladder carcinogenesis

Acrolein, a reactive, alpha,beta-unsaturated aldehyde which is ubiquitous in the environment, forms DNA adducts, is mutagenic, and is teratogenic. However, studies have not indicated a carcinogenic effect in rodent bioassays. Since it is present in cigarette smoke and is the toxic metabolite of cyclophosphamide with respect to the urinary tract, we investigated the possibility that acrolein might have carcinogenic activity toward the rat urinary bladder. We also evaluated whether it possessed initiating and/or promoting activity. To evaluate initiating activity, acrolein was administered at a dose of 2 mg/kg i.p. twice a week for 6 weeks followed by uracil as 3% of the diet for 20 weeks and then control diet for 6 weeks. N-[4-(5-Nitro-2-furyl)-2-thiazolyl]formamide (FANFT) as 0.2% of the diet followed by uracil was used as a positive control, and a negative control group was administered solvent control (water) i.p. during the 6-week initiation period followed by uracil. Acrolein followed by uracil produced an incidence of 18 of 30 rats (60%) with papilloma compared to 8 of 30 rats (27%) treated with solvent control followed by uracil. FANFT followed by uracil produced an incidence of 70% carcinomas and 30% papillomas, clearly indicating that it is a much more potent initiating agent than acrolein. Acrolein for 6 weeks followed by control diet produced no tumors. To evaluate promoting activity, groups of rats were fed FANFT for 6 weeks followed by acrolein. Acrolein administered during the initial 6 weeks and continued for the second phase of the experiment (to evaluate complete carcinogenic activity) resulted in severe toxicity. Administration of acrolein had to be terminated after 21 weeks of the experiment. The animals were maintained for 53 weeks of the experiment without further chemical treatment, and there was no evidence of papilloma or carcinoma development. This study clearly indicates that acrolein has initiating activity for the urinary bladder when administered by i.p. injection to the male F344 rat, but toxicity precluded evaluation of its promoting or complete carcinogenic activity.

Intrapartum care of a woman with aortic aneurysms

Advances in technology and complex care have enabled women with various health problems to become and remain pregnant. Consequently, health-care practitioners are seeing an increasing number of pregnant women who have aortic aneurysms. This case study describes the culturally sensitive intrapartum care of a Middle Eastern woman with ascending and descending aortic aneurysms.

Examination of the hypopharynx predicts ease of laryngoscopic visualization and subsequent intubation: a prospective study of 665 patients

STUDY OBJECTIVE

To determine (a) whether the ability to visualize a patient's airway preoperatively correlates with the ability to visualize his or her larynx during laryngoscopy and (b) whether the presence of certain anatomic characteristics allows anesthetists to predict difficult laryngoscopic visualization and intubation.

DESIGN

Observational. Patients were categorized into two groups: those who had one or more physical characteristics to alert an anesthetist to the possibility of difficult intubation (obesity, overbite, short neck, or decreased neck/jaw mobility) and those with none of these characteristics.

SETTING

University-affiliated hospital.

PATIENTS

Six hundred sixty-five patients scheduled for general anesthesia and requiring endotracheal intubation. Patients were between the ages of 18 and 88 years, with body weight ranging from 21 kg to 141 kg.

INTERVENTIONS

Preoperatively, the anesthetist obtained the best view of the hypopharynx by having the patient extend the tongue and phonate. The airway was then categorized into one of three classes by the ability to see the tonsillar pillars and uvula (Class A, best view--all four tonsillar pillars and uvula seen; Class B, part of the pillars and uvula seen; Class C, worst view--pillars not seen and uvula partially or not seen). After induction, the same anesthetist graded laryngeal visibility into one of four groups depending on his ability to see the patient's epiglottis and vocal cords.

MEASUREMENTS AND MAIN RESULTS

Patients with one or more clinical clues were more likely to have poor visualization of the hypopharynx and, in turn, poor laryngoscopic visualization of the glottis. Patients who had a Class A airway tended to have easy laryngoscopic visualization and were relatively easy to intubate. Conversely, patients with no clinical clues and a Class C airway had poor glottic exposure.

CONCLUSIONS

Our study confirms work showing that the ability to visualize structures of the hypopharynx is a good predictor of subsequent glottic visualization during laryngoscopy and of ease of intubation.

apterous, a gene required for imaginal disc development in Drosophila encodes a member of the LIM family of developmental regulatory proteins

The apterous (ap) gene is required for the normal development of the wing and haltere imaginal discs in Drosophila melanogaster. ap encodes a new member of the LIM family of developmental regulatory genes. The deduced amino acid sequence of ap predicts a homeo domain and a cysteine/histidine-rich domain known as the LIM domain. In these domains ap is highly similar to the mec-3 and lin-11 proteins of Caenorhabditis elegans and to the vertebrate insulin enhancer-binding protein isl-1. ap is presumably required for transcriptional regulation of genes involved in wing and haltere development. The nature of the defects in homozygous null mutant flies is consistent with the pattern of ap expression in the larval imaginal discs. ap is also expressed in a complex pattern in the embryo, including portions of the peripheral nervous system (PNS) and central nervous system (CNS). A requirement for ap expression in the larval and adult CNS may be the underlying cause of the defects in hormone production and vitellogenesis described for ap mutations.

Digital imaging techniques for dental alloy castability quantification

In this study, mesh monitors cast from experimental compositions of a Ni-Cr-Be alloy are evaluated by the application of image analysis techniques. Castability values obtained by this method are then contrasted with those from three commonly employed manual counting procedures. While castability values obtained by all methods reflect the effect of compositional variations, a comparison of results with respect to evaluation method indicates that the image analysis technique consistently yields higher castability values, especially evident in the poorly casting groups. The apparent explanation for these observed differences is that with imaging, segments that are partially cast to varying degrees are not arbitrarily eliminated from the data, as is the usual practice in manual counting methods; therefore, castability values obtained by using the imaging technique will very closely reflect an actual alloy volume of each cast monitor.

Electroconvulsive therapy-induced cardiac arrhythmias during anesthesia with methohexital, thiamylal, or thiopental sodium

STUDY OBJECTIVE

To determine the frequency of electroconvulsive therapy (ECT)-induced arrhythmias under methohexital, thiamylal, or thiopental sodium anesthesia with and without atropine premedication.

DESIGN

A randomized, double-blind study, placebo-controlled for atropine.

SETTING

The inpatient psychiatric unit at a university medical center.

PATIENTS

Forty-nine patients scheduled for ECT.

INTERVENTIONS

Atropine 0.6 mg intravenously (IV) or an equal volume of normal saline IV was given before IV induction of anesthesia with methohexital 0.5 to 1.0 mg/kg, thiamylal 1.5 to 2.5 mg/kg, or thiopental sodium 1.5 to 2.5 mg/kg.

MEASUREMENTS AND MAIN RESULTS

Single-lead electrocardiogram (ECG) recordings were made for 1 minute before induction, during induction of anesthesia, and for 5 minutes after the ECT stimulus. Each ECG was evaluated for arrhythmias and evidence of ischemia in a blinded fashion. Blood pressure and ECG evidence of ischemia did not differ among the groups. Seizure duration was significantly (p less than 0.05) prolonged by a mean of 5 seconds during methohexital anesthesia compared with thiopental sodium and thiamylal (47.6 +/- 18.6 seconds, 42.7 +/- 13.2 seconds, and 42.7 +/- 15.2 seconds, respectively). The frequency of sinus bradycardia was decreased (p less than 0.05) with methohexital (8%) compared with thiopental sodium (20%) and thiamylal (20%). The frequency of premature atrial contractions was decreased (p less than 0.05) with methohexital (43%) compared with thiamylal (61%) but not with thiopental sodium (57%). The frequency of premature ventricular contractions was decreased (p less than 0.05) with methohexital (27%) compared with thiopental sodium (44%) but not with thiamylal (40%). Atropine decreased the frequency of bradycardia (9% vs. 24%) and premature atrial contractions (47% vs. 61%) and increased the frequency of sinus tachycardia (88% vs. 75%).

CONCLUSIONS

These data suggest that anesthesia for ECT therapy should be induced with methohexital to minimize the possibility of potentially life-threatening cardiac arrhythmias. Atropine premedication may further decrease the frequency of premature atrial contractions and bradycardia, while increasing the frequency of tachycardia.

Home visiting for a posthysterectomy population

There are many valid indications for providing home visits to posthysterectomy clients. In-home assessment of the client's status permits immediate care or referrals and saves unnecessary acute care visits to emergency rooms and physicians' offices. Nursing interventions have identified holistic healthcare needs and prevented other problems from developing. Assisting the clients in developing their problem-solving abilities enhances the goal of return to self-care during the immediate postoperative follow-up and afterward. Finally, the vital role the clinical nurse specialists can play in the healthcare system is more clearly established for these consumers of care.