Trauma in congenital atlanto-axial dislocation

Congenital atlanto-axial dislocation (AAD) usually presents with chronically progressive compression of the cervico-medullary junction. However, even a minor trauma can cause acute compression with development of quadruplegia and respiratory impairment. At times these may be transient, or trauma may aggravate the compression and lead to progressive quadriplegia. Of 60 children seen with congenital AAD, in 15 it had been associated with trauma. Nine of these 15 AADs were of the mobile variety, and 6 of the fixed variety with odontoid invagination. In 6 children with mobile and 2 with fixed AAD, trauma led to an acute manifestation with quadriplegia. Three of the children also experienced respiratory distress and needed ventilatory support. All 15 were initially treated with skull traction. Once the condition was stabilised, those with the mobile variety underwent fixation in a reduced position and grafting. One of the children with respiratory distress died within 2 days of admission. In 4 of them, sublaminar wiring between C1 and C2 was carried out, and in 3 others wiring between occiput and base of spinous process of C2 was performed. In 1 case a Hartshill loop was used. Among the children with fixed AAD, reduction of the odontoid invagination was obtained in 2, and they underwent fusion. In 4 cases with unsatisfactory reduction, posterior decompression of the foramen magnum and the fused posterior arch of the atlas was performed. The results depended on the degree of neurological deficit in each child.     

Feasibility of an emergency department-based, risk-targeted voluntary HIV screening program

Renal biopsies from 19 boys and 11 girls, most with moderate or severe forms of hemolytic uremic syndrome (HUS) of the classic diarrhea-associated type, were analyzed as part of their long-term follow-up. Patients were biopsied because of late or persistent proteinuria, hypertension, and prolonged renal failure. The median length of follow-up was 11.2 years (range 0.9-22.0 years). Four histological groups were identified: focal segmental glomerulosclerosis and hyalinosis (FSGSH) (17 patients), diffuse mesangial proliferative glomerulonephritis (DMPGN) (9 patients), diffuse glomerulosclerosis (2 patients), and minimal glomerular changes (2 patients). The median interval between the onset of disease and renal biopsy was significantly shorter in DMPGN than in FSGSH (P < 0.001). The pathological findings may be the expression of two different stages of the same dynamic process: a regular sequence of glomerular lesions consisting of early DMPGN, followed by FSGSH. This lesion would ultimately lead to the final stage of global glomerulosclerosis. At the last examination, only a quarter of the patients had normal renal function. These observations also confirm that prolonged oligoanuria during the acute stage of HUS frequently results in an unfavorable long-term prognosis.     

Dysphonia in the elderly: diagnosis and management of age-related voice changes

In our laryngology practice, we have noted an increasing number of elderly patients referred to us for problematic dysphonia. We present our findings of the most common disorder affecting this age group. A sample of 47 consecutive patients over age 60 with dysphonia revealed presbylaryngis, ie, age-related anatomic and physiologic changes, as the most common etiology found in this tertiary referral practice, accounting for 30% (14 patients) of new diagnoses. None of the patients with presbylaryngis received this diagnosis from the referral source. Understanding the anatomic and physiologic changes of the aging vocal tract, along with the clinical correlation of each change, is crucial in evaluating this group of patients. Managing this disorder includes specific goal-oriented speech therapy, with surgery as an adjunct should conservative therapy prove unsuccessful. Earlier recognition of this disorder and prompt intervention are key factors in reversing vocal decompensation, with a primary effect of improving the quality of life for the patient with age-related dysphonia.     

Application of time series spectral analysis theory: analysis of cardiovascular variability signals

The volume of the anteroventral periventricular nucleus (AVPv) of the rat hypothalamus is larger in females than in males. A preliminary study from this laboratory found that this sexual dimorphism develops between days 30 and 91. The present study was designed to confirm and extend these findings and to determine the role of endogenous gonadal steroids in the development of the AVPv postnatally. The results indicate that the sexual dimorphism in AVPv volume arises between days 30 and 40 and that the length of the nucleus becomes sexually dimorphic between days 60 and 80. Additionally, both AVPv volume and length increased between days 30 and 80 in females. Castration of male rats on the day of birth sex-reversed AVPv volume in adulthood and AVPv length was sex-reversed by castration of males 5 days after birth; ovariectomy of females at these ages had no effect on either parameter. Moreover, in both males and females, AVPv volume and length were unaffected by gonadectomy at later ages. That the AVPv appears to be influenced by testicular hormones neonatally, but changes structurally around the time of puberty in females, clearly challenges current concepts of sexual differentiation that limit the process to the early postnatal period.     

Nitric oxide reduces tumor cell adhesion to isolated rat postcapillary venules

Adhesion of circulating tumor cells to microvascular endothelium plays an important role in tumor metastasis to distant organs. The purpose of this study was to determine whether nitric oxide (NO) would attenuate tumor cell adhesion (TCA) to naive or lipopolysaccharide (LPS)-treated postcapillary venules. A melanoma cell line, RPMI 1846, was shown to be much more adhesive to postcapillary venules isolated from rat mesentery than to corresponding precapillary arterioles. Although venules exposed to LPS for 4 h demonstrated an increased adhesivity for the melanoma cells, TCA to LPS-treated arterioles was not altered. Isolated venules exposed to DETA/NO (1 mM), an NO donor, for 30 min prior to tumor cell perfusion prevented the increment in adhesion induced by LPS and attenuated TCA to naive postcapillary venules. While L-arginine (100 microM), an NO precursor, failed to decrease TCA to naive postcapillary venules, this treatment abolished LPS-stimulated TCA to postcapillary venules. The effect of L-arginine was reversed by administration of N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM), an NO synthase (NOS) inhibitor. These observations indicate that both exogenous and endogenous NO modulate TCA to postcapillary venules. To assess the role of NO-induced activation of cGMP in the reduction in TCA produced by DETA/NO, two additional series of experiments were conducted. In the first series, LY-83583 (10 microM), a guanylyl cyclase inhibitor, was shown to completely reverse the effect of DETA/NO on TCA to both naive and LPS-activated postcapillary venules. On the other hand, administration of 8-bromoguanosine 3',5'-cyclic monophosphate (8-B-cGMP) (1 mM), a cell permeant cGMP analog, mimicked the effect of DETA/NO and reduced TCA to LPS-stimulated postcapillary venules. These data suggest that (a) tumor cells are more likely to adhere to postcapillary venules than to corresponding precapillary arterioles, (b) LPS enhances TCA to postcapillary venules, (c) both exogenously applied (DETA/NO) and endogenously generated (L-arginine) NO attenuate the enhanced adhesion induced by LPS, but only DETA/NO reduced TCA to naive postcapillary venules, and (d) the NO-induced reduction in TCA to LPS-activated postcapillary venules occurs by a cGMP-dependent mechanism.     

Ghosting of pulmonary nodules with respiratory motion: comparison of helical and conventional CT using an in vitro pediatric model

OBJECTIVE: The study was designed to compare helical CT with varying pitch and reconstruction intervals and conventional CT for revealing pulmonary nodules in a model that simulates respiratory motion in children. MATERIALS AND METHODS: CT scans were obtained in an experimental model with one nodule (3 or 10 mm) in each scan. One-second scans were obtained at rates of 10, 20, and 30 respirations per minute using conventional CT with 4-mm collimation and table incrementation and helical CT with 4-mm collimation and either 4-mm/sec (pitch, 1:1) or 8-mm/sec (pitch, 2:1) table speed. Reconstructions were at 1-, 2-, and 4-mm intervals for scans obtained using 4-mm/sec table speed and at 1- and 4-mm intervals for scans obtained using 8-mm/sec table speed. Images were independently reviewed by three radiologists who estimated the number of nodules on each image. RESULTS: Ghosting (depiction of more than one nodule in a study) was seen in 79%, 80%, and 75% of helical CT scans obtained with a 1:1 pitch using 1-, 2-, and 4-mm reconstruction intervals, respectively. By comparison, ghosting was seen in only 54% and 58% of helical CT scans with a 2:1 pitch using 1-mm reconstruction intervals and 4-mm reconstruction intervals, respectively, and in 56% of conventional CT scans (p < .0001). A single nodule was detected on all other scans, and at least one nodule was seen on all scans. CONCLUSION: Ghosting of nodules is common in this model. Ghosting was seen less often on conventional scans and helical scans with 2:1 pitch than it was on helical scans with 1:1 pitch. Nonetheless, ghosting was seen on more than 50% of all scans with each technique.     

Clinical evaluation--difficulties experienced by sessional clinical teachers of nursing: a qualitative study

Evaluation of nursing students in the clinical field requires the clinical teacher to make judgements regarding student progress in a number of areas. In this study concepts of role theory, oppressed group behaviour and the ethics of caring emerged and were used as conceptual frameworks to interpret the data relating to the evaluation of undergraduate students. The number of experienced faculty available for clinical teaching and evaluation has become inadequate and a large number of casual or sessional clinical teachers are employed to teach students in the clinical field. Despite the well documented problems associated with clinical teaching and the use of inexperienced clinical teachers, sessional clinical teachers are nevertheless expected to evaluate student success in meeting the clinical requirements of the nursing course, often resulting in disparate decisions for students. A phenomenological study was carried out using unstructured interviews and written clinical scenarios, to explore the evaluation process from the perspective of the sessional clinical teachers. Research findings indicate that although the sessional clinical teachers were skilled at identifying student problems, they were reluctant to make difficult evaluation decisions, due to low self-esteem, role conflict and their ethic of caring. It seems that gender socialization, patriarchal dominance and apprenticeship training had effected their confidence in their own decision making. The implications of such findings are of concern for the ongoing credibility and integrity of nursing courses, as clinical teachers have an influence on the nursing profession through the preparation of its practitioners.