Effects of acute femoral head ischemia on the growth plate and metaphysis in a piglet model of Legg-Calvé-Perthes disease

OBJECTIVE

To determine the effects of acute (≤7 days) femoral head ischemia on the proximal femoral growth plate and metaphysis in a piglet model of Legg-Calvé-Perthes disease (LCPD). We hypothesized that qualitative and quantitative histological assessment would identify effects of ischemia on endochondral ossification.

DESIGN

Unilateral femoral head ischemia was surgically induced in piglets, and femurs were collected for histological assessment at 2 (n = 7) or 7 (n = 5) days post-ischemia. Samples were assessed qualitatively, and histomorphometry of the growth plate zones and primary spongiosa was performed. In a subset of samples at 7 days, hypertrophic chondrocytes were quantitatively assessed and immunohistochemistry for TGFβ1 and Indian hedgehog was performed.

RESULTS

By 2 days post-ischemia, there was significant thinning of the proliferative and hypertrophic zones, by 63 μm (95% CI -103, -22) and -19 μm (95% CI -33, -5), respectively. This thinning persisted at 7 days post-ischemia. Likewise, at 7 days post-ischemia, the primary spongiosa was thinned to absent by an average of 311 μm (95% CI -542, -82) in all ischemic samples. TGFβ1 expression was increased in the hypertrophic zone at 7 days post-ischemia.

CONCLUSIONS

Alterations to the growth plate zones and metaphysis occurred by 2 days post-ischemia and persisted at 7 days post-ischemia. Our findings suggest that endochondral ossification may be disrupted at an earlier time point than previously reported and that growth disruption may occur in the piglet model as occurs in some children with LCPD.

Quantitative T2 and T1ρ mapping are sensitive to ischemic injury to the epiphyseal cartilage in an in vivo piglet model of Legg-Calvé-Perthes disease

OBJECTIVE

To determine if the quantitative MRI techniques T2 and T1ρ mapping are sensitive to ischemic injury to epiphyseal cartilage in vivo in a piglet model of Legg-Calvé-Perthes disease using a clinical 3T MRI scanner. We hypothesized that T2 and T1ρ relaxation times would be increased in the epiphyseal cartilage of operated vs contralateral-control femoral heads 1 week following onset of ischemia.

DESIGN

Unilateral femoral head ischemia was surgically induced in eight piglets. Piglets were imaged 1 week post-operatively in vivo at 3T MRI using a magnetization-prepared 3D fast spin echo sequence for T2 and T1ρ mapping and a 3D gradient echo sequence for cartilage segmentation. Ischemia was confirmed in all piglets using gadolinium contrast-enhanced MRI. Median T2 and T1ρ relaxation times were measured in the epiphyseal cartilage of the ischemic and control femoral heads and compared using paired t-tests. Histological assessment was performed on a subset of five piglets.

RESULTS

T2 and T1ρ relaxation times were significantly increased in the epiphyseal cartilage of the operated vs control femoral heads (ΔT2 = 11.9 ± 3.7 ms, 95% CI = [8.8, 15.0] ms, P < 0.0001; ΔT1ρ = 12.8 ± 4.1 ms, 95% CI = [9.4, 16.2] ms, P < 0.0001). Histological assessment identified chondronecrosis in the hypertrophic and deep proliferative zones within ischemic epiphyseal cartilage.

CONCLUSIONS

T2 and T1ρ mapping are sensitive to ischemic injury to the epiphyseal cartilage in vivo at clinical 3T MRI. These techniques may be clinically useful to assess injury and repair to the epiphyseal cartilage to better stage the extent of ischemic damage in Legg-Calvé-Perthes disease.

Renal Transplantation With Final Allocation Based on the Virtual Crossmatch

Solid phase immunoassays (SPI) are now routinely used to detect HLA antibodies. However, the flow cytometric crossmatch (FCXM) remains the established method for assessing final donor-recipient compatibility. Since 2005 we have followed a protocol whereby the final allocation decision for renal transplantation is based on SPI (not the FCXM). Here we report long-term graft outcomes for 508 consecutive kidney transplants using this protocol. All recipients were negative for donor-specific antibody by SPI. Primary outcomes are graft survival and incidence of acute rejection within 1 year (AR <1 year) for FCXM+ (n = 54) and FCXM- (n = 454) recipients. Median follow-up is 7.1 years. FCXM+ recipients were significantly different from FCXM- recipients for the following risk factors: living donor (24% vs. 39%, p = 0.03), duration of dialysis (31.0 months vs. 13.5 months, p = 0.008), retransplants (17% vs. 7.3%, p = 0.04), % sensitized (63% vs. 19%, p = 0.001), and PRA >80% (20% vs. 4.8%, p = 0.001). Despite these differences, 5-year actual graft survival rates are 87% and 84%, respectively. AR <1 year occurred in 13% FCXM+ and 12% FCXM- recipients. Crossmatch status was not associated with graft outcomes in any univariate or multivariate model. Renal transplantation can be performed successfully, using SPI as the definitive test for donor-recipient compatibility.

Atypical teratoid rhabdoid tumor: long-term survival after chemoradiotherapy

PURPOSE

Atypical teratoid rhabdoid tumors (ATRTs) arise from the central nervous system largely in the pediatric population. They portend a very poor prognosis with few long-term survivors. We describe a series of five cases at our institution.

METHODS

We conducted a retrospective chart review and clinical follow-up.

RESULTS

Three patients underwent chemoradiation after surgical resection; the two patients whose caretakers declined this therapy passed away soon after diagnosis. Chemoradiation included intravenous and intrathecal chemotherapy as well as intensity-modulated radiotherapy after resection. Of the patients receiving chemoradiation, two patients had infratentorial tumors, two had gross residual tumor after resection, and two were under the age of 3 years. The three patients receiving trimodality therapy remain clinically and symptomatically disease-free with follow-up times of 44, 46, and 55 months. Two of the patients have mild neuropsychiatric sequelae after therapy.

CONCLUSIONS

Long-term, high-volume trials of ATRT are currently not published. We offer experience in successful long-term survival of this tumor treated with chemoradiotherapy.

Does Opening the Peritoneum at the Time of Renal Transplanation Prevent Lymphocele Formation?

BACKGROUND

The occurrence of lymphocele formation following renal transplantation is variable, and the optimal approach to treatment remains undefined. Opening the peritoneum at the time of transplantation is one method of decreasing the incidence of lymphocele formation. The purpose of this study was to determine whether creating a peritoneal window at the time of transplantation decreases the incidence of lymphocele formation.

METHODS

We performed a retrospective review of renal transplants conducted at our institution between 2002 and 2004. Records were reviewed to obtain details regarding opening of the peritoneum at the time of transplant and occurrence of lymphocele. Every patient underwent routine ultrasound imaging in the peri-operative period. Graft dysfunction secondary to the lymphocele was the primary indication for intervention. Data were analyzed by chi-square.

RESULTS

During the initial transplant the peritoneum was opened in 35% of patients. The overall incidence of fluid collections, identified by ultrasound, was 24%. Opening the peritoneum did not decrease the incidence of lymphocele. However, more patients with a closed peritoneum required an intervention for a symptomatic lymphocele. In the 11 patients with an open peritoneum and a fluid collection, only one required an intervention. In patients whose peritoneum was left intact, 24% of fluid collections required intervention. Graft survival was equivalent.

CONCLUSION

Creating a peritoneal window at the time of transplantation did not decrease the overall incidence of postoperative fluid collections. However, forming a peritoneal window at the time of transplantation did decrease the incidence of symptomatic lymphocele.

Relationship between muscle sympathetic nerve activity and systemic hemodynamics during nitric oxide synthase inhibition in humans

Large interindividual differences exist in resting sympathetic nerve activity (SNA) among normotensive humans with similar arterial pressure (AP). We recently showed inverse relationships of resting SNA with cardiac output (CO) and vascular adrenergic responsiveness that appear to balance the influence of differences in SNA on blood pressure. In the present study, we tested whether nitric oxide (NO)-mediated vasodilation has a role in this balance by evaluating hemodynamic responses to systemic NO synthase (NOS) inhibition in individuals with low and high resting muscle SNA (MSNA). We measured MSNA via peroneal microneurography, CO via acetylene uptake and AP directly, at baseline and during increasing systemic doses of the NOS inhibitor NG-monomethyl-l-arginine (l-NMMA). Baseline MSNA ranged from 9 to 38 bursts/min (13 to 68 bursts/100 heartbeats). l-NMMA caused dose-dependent increases in AP and total peripheral resistance and reflex decreases in CO and MSNA. Increases in AP with l-NMMA were greater in individuals with high baseline MSNA ( PANOVA < 0.05). For example, after 8.5 mg/kg of l-NMMA, in the low MSNA subgroup ( n = 6, 28 ± 4 bursts/100 heartbeats), AP increased 9 ± 1 mmHg, whereas in the high-MSNA subgroup ( n = 6, 58 ± 3 bursts/100 heartbeats), AP increased 15 ± 2 mmHg ( P < 0.01). The high-MSNA subgroup had lower baseline CO and smaller decreases in CO with l-NMMA, but changes in total peripheral resistance were not different between groups. We conclude that differences in CO among individuals with varying sympathetic traffic have important hemodynamic implications during disruption of NO-mediated vasodilation.

Vascular adrenergic responsiveness is inversely related to tonic activity of sympathetic vasoconstrictor nerves in humans

In humans, sympathetic nerve activity (SNA) at rest can vary several-fold among normotensive individuals with similar blood pressures. We recently showed that a balance exists between SNA and cardiac output, which may contribute to the maintenance of normal blood pressures over the range of resting SNA levels. In the present studies, we assessed whether variability in vascular adrenergic responsiveness has a role in this balance. We tested the hypothesis that forearm vascular responses to noradrenaline (NA) and tyramine (TYR) are related to SNA such that individuals with lower resting SNA have greater adrenergic responsiveness, and vice-versa. We measured multifibre muscle SNA (MSNA; microneurography), arterial pressure (brachial catheter) and forearm blood flow (plethysmography) in 19 healthy subjects at baseline and during intrabrachial infusions of NA and TYR. Resting MSNA ranged from 6 to 34 bursts min(-1), and was inversely related to vasoconstrictor responsiveness to both NA (r = 0.61, P = 0.01) and TYR (r = 0.52, P = 0.02), such that subjects with lower resting MSNA were more responsive to NA and TYR. We conclude that interindividual variability in vascular adrenergic responsiveness contributes to the balance of factors that maintain normal blood pressure in individuals with differing levels of sympathetic neural activity. Further understanding of this balance may have important implications for our understanding of the pathophysiology of hypertension.

Balance between cardiac output and sympathetic nerve activity in resting humans: role in arterial pressure regulation

Large, reproducible interindividual differences exist in resting sympathetic nerve activity among normotensive humans with similar arterial pressures, resulting in a lack of correlation between muscle sympathetic nerve activity (MSNA) and arterial pressure among individuals. Although it is known that the arterial pressure is the main short-term determinant of MSNA in humans via the arterial baroreflex, the lack of correlation among individuals suggests that the level of arterial pressure is not the only important input in regulation of MSNA in humans. We studied the relationship between cardiac output (CO) and baroreflex control of sympathetic activity by measuring MSNA (peroneal microneurography), arterial pressure (arterial catheter), CO (acetylene uptake technique) and heart rate (HR; electrocardiogram) in 17 healthy young men during 20 min of supine rest. Across individuals, MSNA did not correlate with mean or diastolic blood pressure (r<0.01 for both), but displayed a significant negative correlation with CO (r=-0.71, P=0.001). To assess whether CO is related to arterial baroreflex control of MSNA, we constructed a baroreflex threshold diagram for each individual by plotting the percentage occurrence of a sympathetic burst against diastolic pressure. The mid-point of the diagram (T50) at which 50% of cardiac cycles are associated with bursts, was inversely related to CO (r=-0.75, P<0.001) and stroke volume (SV) (r=-0.57, P=0.015). We conclude that dynamic inputs from CO and SV are important in regulation of baroreflex control of MSNA in healthy, normotensive humans. This results in a balance between CO and sympathetically mediated vasoconstriction that may contribute importantly to normal regulation of arterial pressure in humans.

Mechanism of homophilic adhesion by the neural cell adhesion molecule: use of multiple domains and flexibility

The extracellular regions of adhesion proteins of the Ig superfamily comprise multiple, tandemly arranged domains. We used directforce measurements to investigate how this modular architecture contributes to the adhesive interactions of the neural cell adhesion molecule (NCAM), a representative of this protein class. The extracellular region of NCAM comprises five immunoglobulin and two fibronectin domains. Previous investigations generated different models for the mechanism of homophilic adhesion that each use different domains. We use force measurements to demonstrate that NCAM binds in two spatially distinct configurations. Igdomain deletion mutants identified the domains responsible for each of the adhesive bonds. The measurements also confirmed the existence of a flexible hinge that alters the orientation of the adhesive complexes and the intermembrane distance. These results suggest that a combination of multiple bound states and internal molecular flexibility allows for sequentially synergistic bond formation and the ability to accommodate differences in intercellular space.

Endoscopic-guided trephination dacryocystorhinostomy (Hesham DCR): technique and pilot trial

OBJECTIVES

(1) Test the feasibility and the safety of guided transnasal trephination in creating a nasolacrimal fistula. (2) Develop an appropriate lacrimal maintainer and test its value in modulating healing at the fistula site.

DESIGN

Prospective, noncomparative interventional case series.

PARTICIPANTS

Five cadavers and 19 patients.

METHOD

A transcanalicular lacrimal probe penetrated the lacrimal fossa to guide the passage of a flexible trephine up the nose, which created the nasolacrimal communication. A special wide-caliber lacrimal maintainer was inserted along lacrimal tubes within the created passage.

OUTCOME MEASURES

For cadaveric study, direct inspection after dissection of the facial flap was performed. For the clinical trial, subjective improvement in watery eye, dye testing, lacrimal probing, lacrimal irrigation, and endoscopic nasal examination.

RESULTS

The technique resulted in the creation of a regular fistula of reproducible diameter into which a standard-shaped wide caliber maintainer could be inserted. Three months after removal of the maintainer and 6 months after surgery, a patent ostium was achieved in 17 of 18 (94%) patients who had a completed procedure. Relief of symptoms was achieved in 83%.

CONCLUSIONS

Guided endoscopic dacryocystorhinostomy provides a simple and safe option for the treatment of nasolacrimal duct obstruction. The lacrimal maintainer is a useful device to achieve a large patent nasolacrimal communication.

Assessment tools: are they an effective approach to implementing spiritual health care within the NHS?

Over the last 25 years, many nursing and palliative care journals have carried articles on the subject of 'spiritual' health care. The following is a review of National Health Service (NHS) guidelines and the work of various writers who have contributed to the debate on 'spirit' and 'spiritual needs' from within sociology, palliative care and nursing studies. However, 'spiritual' in the current usage should not be confused with 'religious' and is part of an understanding of what is known as holistic nursing (Dossey et al. 1995). This paper will examine what is meant by 'spiritual' and religious needs and what is indicated by the words 'spiritual' and 'spirit'; and some of the implications for a health care team will be considered. The place of assessment tools in 'spiritual' health care, and the role of the NHS chaplain in the assessment and provision of 'spiritual' health care will be examined.

Age related changes in the tunica media of the vertebral artery: implications for the assessment of vessels injured by trauma

AIMS

To provide an illustrated, detailed semiquantitative analysis of the important degenerative changes along the length of the vertebral artery so that pathologists faced with investigating a fatal arterial injury can identify important pre-existing wall abnormalities.

METHODS

Ten transverse annuli were taken along 34 vertebral arteries from 17 subjects and stained sections were prepared using haematoxylin and eosin and the picro-sirius red method. After routine microscopy, the elastic fibres, collagen, and smooth muscle nuclei in the tunica media were quantified using an eyepiece graticule. An estimate of the severity and extent of elastic tissue fragmentation, collagenous scarring, and intimal thickening/atheroma was then undertaken.

RESULTS

Smooth muscle counts remained constant along the artery but collagen counts were higher and elastic counts substantially lower within the intracranial segment. Elastic fibre fragmentation was recognised in infancy and was moderately advanced by early adulthood but considerable collagenous scarring developed later in life. Some individuals demonstrated severe fragmentation and scarring before the age of 35 years. The degenerative changes were often focal and spared the intracranial segment almost completely. Atheroma increased with age but was rarely severe and appeared not to worsen appreciably beyond the age of 40 years. An unusual arrangement of the collagenous tissue was described within the upper cervical loops.

CONCLUSION

Damaged vertebral arteries need to be sampled extensively to allow a proper histological assessment. The picro-sirius red method was successful in delineating the fine connective tissue structure of the wall and early degenerative changes. An understanding of the age and site specific changes should allow the pathologist to recognise important pre-existing abnormalities more easily.

Effects of intestinal transplantation on postprandial motility and regulation of intestinal transit

BACKGROUND

The effects of intestinal transplantation on gut motility have not been completely defined. In this study we examine the effects of ileal transplantation on ileal smooth muscle contractility, together with gastroduodenal emptying, intestinal flow, and transit rates in a canine model of short-gut syndrome.

METHODS

Animals (n = 22) were instrumented with strain gauge transducers, collection cannulae, and infusion catheters to assess motility, intestinal flow and transit rates, and gastroduodenal emptying. Ten animals served to define normal parameters. Six animals underwent a 70% resection of the proximal small intestine to serve as short-gut controls. Six animals underwent removal of a 100-cm segment of the ileum, with cold storage, and autotransplantation the following day combined with a 70% resection of proximal bowel.

RESULTS

Transplant animals exhibited delayed gastroduodenal emptying, reduced intestinal flow rates, and postprandial phasic contractions that were similar to short-gut controls. However, transplant animals experienced rapid intestinal transit compared with short-gut controls (4.8 +/- 0.4 cm/min vs 2.0 +/- 0.3 cm/min; mean +/- SEM; P <.05).

CONCLUSIONS

The transplanted intestine, even with 18 hours of cold storage, exhibits a relatively normal postprandial motor response. However, adaptive responses of the transplanted intestine, such as regulation of intestine transit, may be impaired by neuromuscular injury associated with denervation or ischemia.

An Islamic understanding of health care: what can it teach us?

Supporting the case for employment and use of non-Christian health care chaplains in the National Health Service (NHS), the Runnymede Trust (1997) states: The inclusiveness or otherwise of a society is seen particularly clearly in the provision which it makes for its members when they fall ill, and perhaps especially when they spend extended time in hospital. At this point of stress and distress in the lives of individuals and their families, are people helped to "maintain their own culture, traditions, language and values"? The Patient's Charter of 1991 requires that health care providers should ensure "respect for privacy, dignity and religious and cultural beliefs".... One way of helping to ensure that such respect is shown is through the appointment of hospital Chaplains.' Although the Patient's Charter (Department of Health 1991) and the subsequent NHS Management Executive document HSG (92)2 (Department of Health 1992) required provision for the religious needs of all patients, in reality, apart from a few exceptions, it led to the appointment of more Church of England Chaplains (Beckford and Gilliat, 1996). Recognizing this problem, Reid and Clarke (1998) indicated NHS Executive willingness to redraw these documents 'provided it comes in the form of a common agreed approach to all faith communities, on the status of chaplaincy and spiritual care in the NHS'.

Deficient iNOS in inflammatory bowel disease intestinal microvascular endothelial cells results in increased leukocyte adhesion

Microvascular endothelial cells play a key role in inflammation by undergoing activation and recruiting circulating immune cells into tissues and foci of inflammation, an early and rate-limiting step in the inflammatory process. We have previously [Binion et al., Gastroenterology112:1898-1907, 1997] shown that human intestinal microvascular endothelial cells (HIMEC) isolated from surgically resected inflammatory bowel disease (IBD) patient tissue demonstrate significantly increased leukocyte binding in vitro compared to normal HIMEC. Our studies [Binion et al., Am. J. Physiol.275 (Gastrointest. Liver Physiol. 38):G592-G603, 1998] have also demonstrated that nitric oxide (NO) production by inducible nitric oxide synthase (iNOS) normally plays a key role in downregulating HIMEC activation and leukocyte adhesion. Using primary cultures of HIMEC derived from normal and IBD patient tissues, we sought to determine whether alterations in iNOS-derived NO production underlies leukocyte hyperadhesion in IBD. Both nonselective (N(G)-monomethyl-L-arginine) and specific (N-Iminoethyl-L-lysine) inhibitors of iNOS significantly increased leukocyte binding by normal HIMEC activated with cytokines and lipopolysaccharide (LPS), but had no effect on leukocyte adhesion by similarly activated IBD HIMEC. When compared to normal HIMEC, IBD endothelial cells had significantly decreased levels of iNOS mRNA, protein, and NO production following activation. Addition of exogenous NO by co-culture with normal HIMEC or by pharmacologic delivery with the long-acting NO donor detaNONOate restored a normal leukocyte binding pattern in the IBD HIMEC. These data suggest that loss of iNOS expression is a feature of chronically inflamed microvascular endothelial cells, which leads to enhanced leukocyte binding, potentially contributing to chronic, destructive inflammation in IBD.

Practice parameter: screening and diagnosis of autism: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Child Neurology Society

Autism is a common disorder of childhood, affecting 1 in 500 children. Yet, it often remains unrecognized and undiagnosed until or after late preschool age because appropriate tools for routine developmental screening and screening specifically for autism have not been available. Early identification of children with autism and intensive, early intervention during the toddler and preschool years improves outcome for most young children with autism. This practice parameter reviews the available empirical evidence and gives specific recommendations for the identification of children with autism. This approach requires a dual process: 1) routine developmental surveillance and screening specifically for autism to be performed on all children to first identify those at risk for any type of atypical development, and to identify those specifically at risk for autism; and 2) to diagnose and evaluate autism, to differentiate autism from other developmental disorders.

A biomechanical study of the human vertebral artery with implications for fatal arterial injury

We studied the biomechanical behaviour of ring and strip specimens from along the length of 18 vertebral arteries taken from 16 subjects aged 28-90 years, in order to consider some of the factors which may play a role in vertebral artery rupture. The method was chosen to allow a comparison between circumferential distension (ring samples) and longitudinal extension, (strip samples). The samples were extended between the jaws of a tensile testing apparatus until the specimen broke and a number of biomechanical parameters were derived. These were the percentage extension to break, the tensile strength, Young's modulus and the peak load. There were a number of important findings. The vertebral artery was shown to be susceptible to longitudinal stretching with a number of strip samples breaking when extended by as little as 16-20%. The tensile strength and load at peak of the strip specimens were correspondingly lower than for the ring samples. Marked intersubject variations were shown for all these parameters and prominent changes in behaviour occurred along the vertebral artery. This study indicates that the artery may be susceptible to head and neck movements which cause the vessel to stretch, and intersubject variations in behaviour may be one important explanation for the marked differences in outcome which appear to exist in subjects who suffer broadly similar head and neck insults.

Improved graft survival after renal transplantation in the United States, 1988 to 1996

BACKGROUND

The introduction of cyclosporine has resulted in improvement in the short-term outcome of renal transplantation, but its effect on the long-term survival of kidney transplants is not known.

METHODS

We analyzed the influence of demographic characteristics (age, sex, and race), transplant-related variables (living or cadaveric donor, panel-reactive antibody titer, extent of HLA matching, and cold-ischemia time), and post-transplantation variables (presence or absence of acute rejection, delayed graft function, and therapy with mycophenolate mofetil and tacrolimus) on graft survival for all 93,934 renal transplantations performed in the United States between 1988 and 1996. A regression analysis adjusted for these variables was used to estimate the risk of graft failure within the first year and more than one year after transplantation.

RESULTS

From 1988 to 1996, the one-year survival rate for grafts from living donors increased from 88.8 to 93.9 percent, and the rate for cadaveric grafts increased from 75.7 to 87.7 percent. The half-life for grafts from living donors increased steadily from 12.7 to 21.6 years, and that for cadaveric grafts increased from 7.9 to 13.8 years. After censoring of data for patients who died with functioning grafts, the half-life for grafts from living donors increased from 16.9 years to 35.9 years, and that for cadaveric grafts increased from 11.0 years to 19.5 years. The average yearly reduction in the relative hazard of graft failure after one year was 4.2 percent for all recipients (P<0.001), 0.4 percent for those who had acute rejection (P=0.57), and 6.3 percent for those who did not have acute rejection (P<0.001).

CONCLUSIONS

Since 1988, there has been a substantial increase in short-term and long-term survival of kidney grafts from both living and cadaveric donors.

Reduction of myocardial nitrosyl complex formation by a nitric oxide scavenger prolongs cardiac allograft survival

Nitric oxide synthase (NOS) inhibitors have been shown to reduce NO but yield conflicting results on cardiac allograft survival. In this study, we provide an alternative approach specifically to examine the efficacy of a NO scavenger on nitrosyl complex formation and graft survival in a model of heterotopic cardiac transplantation. Efficacy was examined under both acute and chronic conditions (i.e., without or with immunosuppression, respectively). Electron paramagnetic resonance (EPR) spectroscopy of frozen myocardial tissue from untreated allografts showed progressive increases in nitrosylheme and nitrosomyoglobin before graft failure. These signals were not seen in either isografts or native hearts of allograft recipients. Both plasma nitrate plus nitrite and myocardial nitrosyl complex formation in cardiac allografts were significantly decreased in recipient animals treated with the NO scavenger, NOX-100, or by low-dose cyclosporine (CsA). Both interventions were nearly equivalent in significantly prolonging graft survival. The short-term combination treatment of both NOX-100 plus CsA completely eliminated myocardial nitrosyl complex formation and synergistically prolonged graft survival. Long-term combination drug treatment (days 0-100) followed by cessation of therapy resulted in permanent graft acceptance with no evidence for nitrosyl complex formation. These studies support a role of NO in cardiac allograft rejection. Furthermore, these studies indicate a potential therapeutic value of NO scavengers in preventing organ rejection.

The screening and diagnosis of autistic spectrum disorders

The Child Neurology Society and American Academy of Neurology recently proposed to formulate Practice Parameters for the Diagnosis and Evaluation of Autism for their memberships. This endeavor was expanded to include representatives from nine professional organizations and four parent organizations, with liaisons from the National Institutes of Health. This document was written by this multidisciplinary Consensus Panel after systematic analysis of over 2,500 relevant scientific articles in the literature. The Panel concluded that appropriate diagnosis of autism requires a dual-level approach: (a) routine developmental surveillance, and (b) diagnosis and evaluation of autism. Specific detailed recommendations for each level have been established in this document, which are intended to improve the rate of early suspicion and diagnosis of, and therefore early intervention for, autism.

Clinical efficacy of the Abbott Tacrolimus II assay for the IMx

Monitoring tacrolimus is essential to maintain therapeutic concentrations. Performance of the new Abbott Tacrolimus assay (FK II) was evaluated and compared to the original tacrolimus assay (FK I). 189 trough whole blood samples from transplant cases were included in the study. Samples (n = 117) with FK I concentrations > 5 ng/mL were reanalyzed with the FK II assay. Patient samples (n = 43) that had FK I concentration < 5 ng/mL with apparent mean and range of 3.1 ng/mL and 0.7 to 4.5 ng/mL, respectively, were also reanalyzed with FK II to yield a mean of 5.9 ng/mL with a range of 2.9 to 10.8 ng/mL. Checking for patient compliance, samples (n = 10) with a FK I concentration of 0 ng/mL were re-analyzed. With one exception of a mislabeled cyclosporine sample, all samples (n = 9) showed FK506 levels greater than 2 ng/mL with the FK II assay. The FK II assay was shown to be a clinically efficacious assay, with improved sensitivity and acceptable precision versus the previous FK I assay.

American Academy of Pediatrics. Committee on Children With Disabilities. Care coordination: integrating health and related systems of care for children with special health care needs

Care coordination is a process that links children with special health care needs and their families to services and resources in a coordinated effort to maximize the potential of the children and provide them with optimal health care. Care coordination often is complicated because there is no single entry point to multiple systems of care, and complex criteria determine the availability of funding and services among public and private payers. Economic and sociocultural barriers to coordination of care exist and affect families and health care professionals. In their important role of providing a medical home for all children, primary care pediatricians have a vital role in the process of care coordination, in concert with the family.

Recurrent and de novo glomerular disease after renal transplantation: a report from Renal Allograft Disease Registry (RADR)

INTRODUCTION

Short-term and long-term results of renal transplantation have improved over the past 15 years. However, there has been no change in the prevalence of recurrent and de novo diseases. A retrospective study was initiated through the Renal Allograft Disease Registry, to evaluate the prevalence and impact of recurrent and de novo diseases after transplantation.

MATERIALS AND METHODS

From October 1987 to December 1996, a total of 4913 renal transplants were performed on adults at the Medical College of Wisconsin, University of Cincinnati, University of California at San Francisco, University of Louisville, University of Washington, Seattle, and Washington University School of Medicine. The patients were followed for a minimum of 1 year. A total of 167 (3.4%) cases of recurrent and de novo disease were diagnosed by renal biopsy. These patients were compared with other patients who did not have recurrent and de novo disease (n=4746). There were more men (67.7% vs. 59.8%, P<0.035) and a higher number of re-transplants (17% vs. 11.5%, P<0.005) in the recurrent and de novo disease group. There was no difference in the rate of recurrent and de novo disease according to the transplant type (living related donor vs. cadaver, P=NS). Other demographic findings were not significantly different. Common forms of glomerulonephritis seen were focal segmental glomerulosclerosis (FSGS), 57; immunoglobulin A nephritis, 22; membranoproliferative glomerulonephritis (GN), 18; and membranous nephropathy, 16. Other diagnoses include: diabetic nephropathy, 19; immune complex GN, 12; crescentic GN (vasculitis), 6; hemolytic uremic syndrome-thrombotic thrombocytopenic purpura (HUS/TTP), 8; systemic lupus erythematosus, 3; Anti-glomerular basement membrane disease, 2; oxalosis, 2; and miscellaneous, 2. The diagnosis of recurrent and de novo disease was made after a mean period of 678 days after the transplant. During the follow-up period, there were significantly more graft failures in the recurrent disease group, 55% vs. 25%, P<0.001. The actuarial 1-, 2-, 3-, 4, and 5-year kidney survival rates for patients with recurrent and de novo disease was 86.5%, 78.5%, 65%, 47.7%, and 39.8%. The corresponding survival rates for patients without recurrent and de novo disease were 85.2%, 81.2%, 76.5%, 72%, and 67.6%, respectively (Log-rank test, P<0.0001). The median kidney survival rate for patients with and without recurrent and de novo disease was 1360 vs. 3382 days (P<0.0001). Multivariate analysis using the Cox proportional hazard model for graft failure was performed to identify various risk factors. Cadaveric transplants, prolonged cold ischemia time, elevated panel reactive antibody, and recurrent disease were identified as risk factors for allograft failure. The relative risk (95% confidence interval) for graft failure because of recurrent and de novo disease was 1.9 (1.57-2.40), P<0.0001. The relative risk for graft failure because of posttransplant FSGS was 2.25 (1.6-3.1), P<0.0001, for membranoprolifera. tive glomerulonephritis was 2.37 (1.3-4.2), P<0.003, and for HUS/TTP was 5.36 (2.2-12.9), P<0.0002. There was higher graft failure (64.9%) and shorter half-life (1244 days) in patients with recurrent FSGS.

CONCLUSION

In conclusion, recurrent and de novo disease are associated with poorer long-term survival, and the relative risk of allograft loss is double. Significant impact on graft survival was seen with recurrent and de novo FSGS, membranoproliferative glomerulonephritis, and HUS/TTP.

Renal transplantation for end-stage renal disease following bone marrow transplantation: a report of six cases, with and without immunosuppression

BACKGROUND. Over 12000 bone marrow transplantations (BMT) are performed in the USA each year. This procedure is associated with significant morbidity including acute and chronic renal failure (CRF). CRF after BMT is usually secondary to radiation nephropathy and,or cyclosporine (CsA) toxicity. Survival on dialysis therapy for patients with radiation nephropathy is poor and renal transplantation may be a preferable form of renal-replacement therapy.

METHODS

We report our experience with renal transplantation in 6 patients with end-stage renal disease (ESRD) following BMT: 4 as a result of radiation nephropathy; one secondary to hemolytic uremic syndrome; and 1 as a result of antitubular basement membrane nephritis. Ages at the time of BMT ranged from 26 to 40 yr. ESRD developed after a mean period of 94 months (range 42-140 months) after BMT. The kidney source was from a living donor in 5 patients, and a cadaveric donor (CAD) in 1 patient. In 3 recipients, the bone marrow and kidney were from the same donor. They are managed without any immunosuppressive therapy. The other 3 were initiated on triple therapy (prednisone, mycophenolate mofetil/azathioprine and cyclosporine/tacrolimus).

RESULTS

These patients have been followed for up to 31 months (range 3-30 months) after kidney transplant, and 5 out of 6 are alive with functioning bone marrow and renal transplants. Their plasma creatinines range from 70 to 160 micromol/L (mean 97 micromol/L). One patient died following metastatic squamous cell cancer of the genital tract.

CONCLUSIONS

1) Renal transplant is a feasible alternative for patients with ESRD following BMT: 2) if bone marrow and kidney are from the same donor, the recipient requires little or no maintenance immunosuppression; 3) short-term results show good survival, but long-term follow-up is needed: 4) infections and malignancy post-renal transplantation were seen in recipients who needed immunosuppression; and 5) reduction in immunosuppression may be needed in such post-BMT patients who undergo kidney transplants.

Inflammatory modulation of calcium-activated potassium channels in canine colonic circular smooth muscle cells

BACKGROUND & AIMS

The characteristics of colonic circular smooth muscle slow waves are altered during inflammation. The aim of this study was to examine whether inflammation modulates the open-state probability of Ca2+-activated K+ (KCa) channels in these cells to contribute to these alterations.

METHODS

The experiments were performed on freshly dissociated single smooth muscle cells from the canine colon using standard patch clamp methods. Inflammation was induced by mucosal exposure to ethanol and acetic acid.

RESULTS

Inflammation decreased the open-state probability of large-conductance KCa (BK) channels in the cell-attached and excised inside-out configurations. The voltage sensitivity of the channels was also reduced during inflammation. Inflammation had no significant effect on the large, medium, and small conductances or the unitary current levels of channel openings. However, it decreased the maximum number of simultaneous channel openings. The channels were Ca2+-dependent and were blocked by tetraethylammonium and charybdotoxin in normal and inflamed cells.

CONCLUSIONS

Inflammation decreases the open-state probability of BK channels. This may partially reverse the decrease in duration and amplitude of slow waves and depolarization of membrane potential seen in inflammation.

Pre-transplant identification of risk factors that adversely affect length of stay and charges for renal transplantation

BACKGROUND

In the current era of renal transplantation, increasing attention is being focused on resource utilization. The purpose of this study was to identify demographic, medical and immunologic risk factors that are associated with changes in length of stay (LOS) and charges for renal transplantation.

METHOD

The study was a retrospective analysis of 311 consecutive renal transplants performed at a single institution. Univariate and multivariate analyses were used to examine relationships between risk factors, LOS, charges and post-operative complications.

RESULTS

The following pre-transplant variables were found to be independently significant in predicting increased LOS and/or charges: African-American race, obesity for women, chronic obstructive pulmonary disease (COPD), presence of cardiac disease or previous stroke, pre-transplant dialysis time > or = 1 yr, a 10% increase in panel reactive antibody (PRA), cadaver donor and retransplantation. The analyses were performed with and without adjustment for key outcome variables such as delayed graft function (DGF) and use of induction antibody therapy. Increased LOS or charges for specific risk factors could be attributed to increased complication rates, including delayed graft function seen with various co-morbidities, or increased immunologic risk and more frequent use of induction antibody therapy.

CONCLUSION

Analysis of linked financial and clinical databases can reveal demographic, medical and immunologic risk factors that correlate with LOS, charges and complications for renal transplantation. Efforts to establish quantitative relationships for various risk factors relative to resource utilization will become important in managed care and/or capitated healthcare delivery systems.

Acute torsion of the renal transplant after combined kidney-pancreas transplant

BACKGROUND

Surgical complications after combined kidney and pancreas transplantation are a major source of morbidity and mortality. Complications related to the pancreas occur with greater frequency as compared to renal complications. The occurrence in our practice of two cases of renal infarction resulting from torsion about the vascular pedicle led to our retrospective review of similar vascular complications after combined kidney and pancreas transplantation.

METHODS

Charts were reviewed retrospectively, and two patients were identified who experienced torsion about the vascular pedicle of an intra-abdominally placed renal allograft.

RESULTS

Two patients who had received combined intraperitoneal kidney and pancreas transplantation presented at 16 and 11 months after transplant, respectively, with abdominal pain and decreased urine output. One patient had radiological documentation of abnormal rotation before the graft loss; unfortunately, the significance of this finding was missed. Diagnosis was made in both patients at laparotomy, where the kidneys were infarcted secondary to torsion of the vascular pedicle. Both patients underwent transplant nephrectomy and subsequently received a successful second cadaveric renal transplant.

CONCLUSIONS

The mechanism of this complication is a result of the intra-abdominal placement of the kidney, length of the vascular pedicle, excess ureteral length, and paucity of adhesions secondary to steroid administration. These factors contribute to abnormal mobility of the kidney. Technical modifications such as minimizing excess ureteral length and nephropexy may help to avoid this complication.

Prognostic value of intraoperative blood flow measurements in vascular access surgery

BACKGROUND

The purpose of this study was to correlate intraoperative blood flow measurements with outcome in vascular access surgery.

METHODS

In 303 patients, 389 vascular access operations were performed. Intraoperative blood flow measurements were made immediately following construction of 227 autogenous and 162 prosthetic arteriovenous fistulas (AVFs) using a handheld flowprobe. Blood flow measurements were stratified by demographic variables such as age, race, sex, and presence of diabetes and were correlated with primary and secondary (assisted) patency. Statistical methods included life-table analysis and Cox proportional hazards model.

RESULTS

Blood flow increased progressively from distal to proximal access sites and was not significantly affected by age, race, sex, or presence of diabetes. Autogenous AVFs with flow rates at or below 320 mL/min and polytetrafluoroethylene (PTFE) grafts with flow rates at or below 400 mL/min had significantly worse primary and secondary patency rates compared to their higher flow counterparts at all sites. Using hazard analysis flow rate was the single most important determinant of primary and secondary patency. PTFE grafts with flow rates at or below 400 mL/min also required more interventions (1.58 per patient-year) and failed sooner (median time, 0.5 +/- 4.7 months) than grafts with flow rates above 400 mL/min (1.08 interventions per patient-year; P = .03; median time, 1.6 +/- 5.0 months; P = .003).

CONCLUSIONS

Intraoperative measurements of access blood flow provide objective, reliable data that correlate with outcome. Routine use of this technology might lead to more efficient management of patients undergoing hemodialysis access surgery.

Recurrent and de novo renal diseases after renal transplantation: a report from the renal allograft disease registry

Recurrent or de novo glomerular disease is an important cause of graft dysfunction and eventual loss. Cyclosporine A (CyA) has improved short-term renal allograft outcome but has not altered long-term graft survival. The purpose of the current study is to determine the prevalence of such disease and its impact on graft function in the CyA era. From 1984 to 1994, 1,557 renal allografts were performed at the Medical College of Wisconsin and the University of Cincinnati. Patients were followed up for an average of 7.2 years (minimum, 1 year). Recurrent disease was diagnosed by renal biopsy in 98 (6.3%) patients after an average of 36 months. Demographic characteristics of patients with and without recurrent disease were similar. Glomerulonephritis was the most common finding, occurring in 73 patients, and included focal segmental glomerulosclerosis (FSGS), 25; IgA nephropathy (IgAN), 11; membranous (MN), 11; proliferative, 11; membranoproliferative glomerulonephritis (MPGN), 10; glomerular basement membrane (anti-GBM), 3; and systemic lupus erythematosus (SLE), two. Diabetic nephropathy was present in 22, hemolytic uremic syndrome (HUS) in two, and oxalosis in one. Graft loss occurred in 60 of 98 (61%) recipients. Half-life of the allograft was diminished in patients with recurrent disease, 2,038 +/- 225 versus 3,135 +/- 385 days, P = 0.002. The actuarial allograft survival at 1, 3, 5, and 8 years posttransplantation with recurrence was 88%, 74%, 57%, and 34%, respectively; and the corresponding graft survival for patients without recurrent disease was 80%, 70%, 64%, and 53%, respectively (P = 0.003). The risk of recurrent disease increased with length of graft survival from 2.8% at 2 years to 9.8% and 18.5% at 5 and 8 years, respectively. We conclude that recurrent disease is a significant problem after renal transplantation and is associated with decreased graft survival.

Experimental inoculation of mice with trypsin-resistant and trypsin-sensitive avian reoviruses

Groups of sucking Swiss albino mice were inoculated by the intracerebral (i.c.), intraperitoneal (i.p.) or oral route with a trypsin-sensitive avian reovirus (TR1) or a trypsin-resistant (R2) reovirus. The viruses caused a number of effects, the most severe occurring after i.c. inoculation and the least after oral inoculation. They included incoordination and tremors, oiliness of the hair, and retarded growth. Patterns of viral persistence in tissues were similar for the two viruses, with high titres in the brain on days 3 and 6 after i.c. or i.p. injection. Both viruses were still present in the brain 21 days after i.c. injection. No virus was found in any tissue when TR1 was given orally. All groups "seroconverted" except the one infected orally with TR1, but neutralization titres were low. The effects resembled those described for mammalian reoviruses in mice. The results indicate that, for short periods, wild mice may be capable of transmitting avian reoviruses between poultry flocks. Furthermore, in the production of monoclonal antibodies to avian reoviruses in mice, it is possible that pathological changes will occur.

Postprandial motor activity and its relationship to transit in the canine ileum

BACKGROUND

The purpose of this study was to elucidate the mechanism of reduced intestinal transit rate in the ileum as compared with the jejunum.

METHODS

Twenty-one dogs were each instrumented with 12 strain gauge transducers, 2 collection cannulas, and an infusion catheter defining a 100 cm study in the midjejunum (n = 11) and midileum (n = 10). Postprandial motor activity and intestinal transit were measured 1 hour after ingestion of a 650 kcal solid meal. Contractile activity was analyzed by means of computer programs that determine frequency, amplitude, and propagation behavior of circular smooth muscle contractions.

RESULTS

Postprandial ileal contractions occurred with greater frequency (13.7 +/- 2.5 versus 11.5 +/- 0.4; p = 0.04) and displayed a higher incidence of propagation (61% +/- 2% versus 44% +/- 3%; p = 0.0001) than jejunal contractions, but traveled at significantly slower rates (1.0 +/- 0.7 cm/sec vs 3.7 +/- 0.9 cm/sec; p = 0.0001). The net result was significantly slower transit in the ileum compared with the jejunum (4.7 +/- 0.7 cm/min versus 13.1 +/- 1.5 cm/min; p = 0.0006). Within each region, transit correlated with parameters of propagating contractions. Stepwise regression of the combined data revealed that contraction velocity was the most important variable determining intestinal transit rate (r = 0.64; p < 0.001).

CONCLUSIONS

Contrary to previous thinking, postprandial ileal contractions display a high degree of temporal and spatial organization. Slow ileal transit is mainly due to reduced propagation velocity, which is intrinsic to the circular smooth muscle.

Management of severe pancreatitis in renal transplant recipients

OBJECTIVE

The authors determine if any aspects of the treatment of renal transplant patients with pancreatitis were of particular benefit with regard to graft and patient survival.

BACKGROUND

The incidence of pancreatitis in renal transplant patients is low (1%-2%), but the mortality of the disease approaches 100%. Although several descriptive reports have been published, there is no consensus-regarding management.

METHODS

The authors conduct a retrospective chart review.

RESULTS

Twenty-one patients were identified with posttransplant pancreatitis (1.3% incidence). The cause of pancreatitis was presumed to be maintenance immunosuppression in all cases. Patients were classified by dynamic computed tomography (CT) scans having 1) mild/edematous disease (4 patients), 2) localized abscess or pseudocyst (6 patients), or 3) severe disease (11 patients). Patients with mild/edematous pancreatitis did well with medical management. The six patients with localized abscess or pseudocyst were successfully treated with standard operative intervention. Of the 11 patients with severe disease, 6 had several days of intensive medical management before operation, and all died. The other five patients underwent early operative intervention based principally on CT scan findings, and all survived. The latter group had multiple operations and four of five had functioning renal allografts at discharge.

CONCLUSION

The severity of pancreatitis in the posttranplant patients may be difficult to assess by clinical criteria. Dynamic CT scanning is, therefore, essential in defining the extent of disease. Early, and perhaps repeated, operations may be lifesaving in those patients having CT scan findings of severe pancreatitis.

The differential contribution of spinopetal projections to increases in vocalization and motor reflex thresholds generated by the microinjection of morphine into the periaqueductal gray

The capacity of morphine microinjected into the ventrolateral periaqueductal gray (vPAG) to elevate the thresholds of spinal motor reflexes (SMRs), vocalizations during shock (VDSs) and vocalization afterdischarges (VADs) was challenged by the intrathecal administration of receptor antagonists to serotonin (methysergide), norepinephrine (phentolamine) and mu-opiates (naloxone). Methysergide and phentolamine were equipotent in reversing increases in SMR thresholds. The efficacy of these antagonists to reduce increases in VDS and VAD thresholds was dependent on the dose of morphine administered into the vPAG. These results indicate that the dose of morphine administered into the vPAG determines the contribution of spinopetal projections in inhibiting dorsal horn neurons involved in reflex generation versus the rostral transmission of pain information. A hypothesis is offered regarding the mechanisms by which vPAG administered morphine suppresses nociceptive transmission through different levels of the neuraxis.

Increases in vocalization and motor reflex thresholds generated by the intrathecal administration of serotonin or norepinephrine

The capacity of serotonin and norepinephrine to elevate the thresholds of spinal motor reflexes (SMRs), vocalizations during shock (VDSs), and vocalization afterdischarges (VADs) when administered into the spinal subarachnoid space was evaluated. Both monoamines generated dose-dependent increases in the thresholds of all 3 responses. The minimum effective doses of serotonin and norepinephrine that elevated all 3 response thresholds were 40 micrograms and 1 microgram respectively. Monoamine-induced increases in response thresholds were reversed by the intrathecal administration of their corresponding receptor antagonists (phentolamine or methysergide). Threshold increases generated by serotonin were also partially reduced by phentolamine. These results indicate that dorsal horn neurons that underlie flexion reflex generation (SMR) and the rostral transmission of pain information (VDS and VAD) have similar thresholds of inhibition to spinopetal monoaminergic projections.

Myoelectric activity and absorptive capacity of rat small intestinal isografts

The effect of transplantation on small intestinal absorption, digestive capacity, myoelectric activity, and morphology was assessed in inbred Lewis rats. Electrodes were sutured to the duodenum and isografted jejunoileum or to the native jejunoileum in controls. The frequency of migrating myoelectric complexes (MMCs) in the duodenum was 3.3 +/- 0.3/hr in controls and 1.8 +/- 0.4/hr in transplants (P < 0.05). MMC frequency in the jejunoileum was 5.1 +/- 1.3/hr in controls and 3.2 +/- 0.9/hr in transplants (P > 0.05). MMCs appeared to migrate from the duodenum to the jejunoileum 80 +/- 3% of the time in controls and 59 +/- 7% of the time in transplant rats (P < 0.05). Absorption in the transplanted jejunoileum demonstrated a 35-40% decrease in glucose and electrolytes absorption. Villus height and number of nuclei per villus was reduced. Intestinal length (dry) was 103 +/- 6 cm for controls and 51 +/- 3 cm for transplant rats (P < 0.05). Brush border sucrase activity was unchanged. We conclude that small intestinal isografts display similar myoelectric activity as controls, but the decreased absorptive capacity and villus height may require longer segments of intestine to be transplanted in order to support normal nutrition.

The differential contribution of spinopetal projections to increases in vocalization and motor reflex thresholds generated by the microinjection of morphine into the periaqueductal gray

The capacity of morphine microinjected into the ventrolateral periaqueductal gray (vPAG) to elevate the thresholds of spinal motor reflexes (SMRs), vocalizations during shock (VDSs) and vocalization afterdischarges (VADs) was challenged by the intrathecal administration of receptor antagonists to serotonin (methysergide), norepinephrine (phentolamine) and mu-opiates (naloxone). Methysergide and phentolamine were equipotent in reversing increases in SMR thresholds. The efficacy of these antagonists to reduce increases in VDS and VAD thresholds was dependent on the dose of morphine administered into the vPAG. These results indicate that the dose of morphine administered into the vPAG determines the contribution of spinopetal projections in inhibiting dorsal horn neurons involved in reflex generation versus the rostral transmission of pain information. A hypothesis is offered regarding the mechanisms by which vPAG administered morphine suppresses nociceptive transmission through different levels of the neuraxis.

Delayed gastroduodenal emptying is an important mechanism for control of intestinal transit in short-gut syndrome

PURPOSE

To understand the relative importance of changes in ileal smooth muscle contractility versus alteration of intestinal flow rate as control mechanisms for regulating intestinal transit in a surgical model of short-gut syndrome.

METHODS

A model of short-gut syndrome was created by performing a 70% proximal small-bowel resection in dogs. Ten control and 6 animals with short-gut syndrome were instrumented with strain gauge transducers, steel collection cannulas, and a Silastic intraluminal infusion catheter in the midileum. Motor activity was analyzed by computer programs that determine frequency, amplitude, and propagation behavior of postprandial contractions. Perfusions of 14C-polyethylene glycol and bolus injection of 3H-polyethylene glycol were used to determine intestinal flow and transit rates. Total gastroduodenal emptying was determined using a 14C-polyethylene glycol-labelled meal.

RESULTS

Postprandial contraction frequency was decreased in animals with short-gut syndrome, but other significant changes in amplitude, mean area, and propagation behavior of postprandial ileal contractions were not seen. Gastroduodenal emptying and mean intestinal flow rates were markedly slower in animals with short-gut syndrome, as were intestinal transit rates.

CONCLUSIONS

In this model of short-gut syndrome, the major adaptive change is decreased intestinal flow rate, related to delayed gastroduodenal emptying. The spatial organization of ileal contractions does not change substantially aside from a change in frequency which can be accounted for by transection of the intestinal wall.

Prevalence of glaucoma after surgery for PHPV and infantile cataracts

The prevalence of glaucoma associated with pediatric aphakia has been reported to range from 0% to 27%. Few studies have included a significant number of patients with persistent hyperplastic primary vitreous (PHPV) cataracts. The purpose of this study was to evaluate the prevalence of glaucoma in young children undergoing surgery for PHPV and infantile cataracts. The charts of all of the patients who underwent lensectomy/vitrectomy for infantile and PHPV cataracts at the University of Iowa Hospitals and Clinics between 1975 and 1992 were reviewed. Patients with ocular abnormalities that might predispose to glaucoma and patients with less than 6 months follow up were excluded. A total of 72 patients (109 eyes) were identified: 25 patients (26 eyes) with PHPV cataracts and 47 patients (83 eyes) with infantile cataracts. Mean age at time of surgery for both groups was 3.5 months. Mean follow up was 84.5 months for those with PHPV, and 76.9 months for those with infantile cataracts. Glaucoma developed in eight (32%) of the 25 patients with PHPV and in 15 (32%) of the 47 with infantile cataracts. Mean time to onset of glaucoma was 64.6 months for those with PHPV and 47.5 months for those with infantile cataracts (P = .70). Although there was no significant difference between the prevalence of postoperative glaucoma in those with infantile and those with PHPV cataracts, the prevalence of glaucoma in these patients is high. Children with aphakia should be closely monitored for glaucoma throughout their lives.

A necropsy and histomorphometric study of abnormalities in the course of the vertebral artery associated with ossified stylohyoid ligaments

AIMS

To establish whether abnormalities in the course of the vertebral artery occur and whether they are relevant to arterial injury associated with head and neck movements.

METHODS

Twenty vertebral arteries were carefully dissected at necropsy and abnormalities in course were noted, along with any other bony or cartilaginous cervical anomalies. The effect of head and neck movement on these vessels was studied before a detailed histomorphometric examination was undertaken on sections of the excised arteries.

RESULTS

Five vessels had an abnormal course. One vessel entered the transverse foramina of the fifth cervical vertebra rather than the sixth, but was otherwise normal. In two subjects both vertebral arteries were abnormal in the upper cervical portion with, in each case, a straight left vertebral artery and a right vertebral artery with a deficient loop, closely applied to the atlanto-axial joint. Both of these subjects also had completely ossified stylohyoid ligaments and the arteries visibly stretched with modest head and neck movements. Histology revealed variable degrees of smooth muscle disarray in the tunica media of two of the arteries with loop deficiencies. The circumference of one of the straight arteries was smaller than expected but in all other measured histomorphometric parameters these vessels appeared normal.

CONCLUSIONS

Vertebral artery loops are deficient in a number of subjects. This finding is important given the recently described biomechanical susceptibility of the vertebral artery to longitudinal extension and may explain the smooth muscle changes, in that this may represent attempts at arterial wall remodelling. Subjects with such loop deficiencies may be more susceptible to a variety of head and neck insults and such abnormalities should be sought at necropsy in subjects who die as a result of fatal vertebral artery injury.

Highly variable gastric emptying in patients with insulin dependent diabetes mellitus

Some diabetic patients--particularly those with nausea and vomiting--frequently have evidence of delayed gastric emptying while other diabetic patients may in fact exhibit accelerated gastric emptying. Whether the presence or absence of symptoms of upper gastrointestinal dysfunction correlated with objective measures of gastric emptying in insulin dependent diabetic subjects was investigated. Twenty one insulin dependent diabetic patients underwent a solid phase gastric emptying scintiscan using in vivo labelled chicken liver. Thirteen patients had symptoms suggestive of gastrointestinal dysfunction (nausea, vomiting, early satiety, or constipation), while eight patients had no gastrointestinal symptoms. Eleven patients had orthostatic hypotension. All patients had been diabetic since childhood or adolescence. As a group, the diabetic patients showed a half time (T50) of gastric emptying (mean (SD) 150.0 min (163.7) that was not significantly different from that of 12 healthy control subjects (148.1 min (62.4)). Those diabetic patients without gastrointestinal symptoms and without orthostatic hypotension, however, showed a gastric emptying half time (70.1 min (41.6)) that was significantly faster than that of the control subjects. Conversely, those diabetic patients with nausea, vomiting, and early satiety (or early satiety alone) showed T50 values that were significantly greater than those of the diabetic patients without these symptoms. No correlation was found between the T50 value and the duration of diabetes, the fasting blood glucose at the time of study, or the respiratory variation in heart rate (E:I ratio). These observations indicate that highly variable rates of gastric emptying occur in insulin dependent diabetic patients, and that accelerated gastric emptying may occur in diabetic patients who have no symptoms of gastrointestinal dysfunction.