A recent decrease in the time to development of monomorphous and polymorphous posttransplant lymphoproliferative disorder.

We have noted a decrease in the time to development of posttransplant lymphoproliferative disorder (PTLD) over the last two and one-half years in our multiorgan transplant program. From February 1965 until December 1990, 1622 transplants were performed including 1489 kidneys (KTxp), 87 livers (LTxp), and 46 pancreata. Between February 1965 and July 1988 (group 1), there were 1260 transplants performed and nine cases of either monomorphous PTLD (M-PTLD, n = 8) or polymorphous PTLD (P-PTLD, n = 1) were diagnosed. The mean time to development of PTLD was 163 +/- 128 weeks, all after KTxp. Five of these nine patients received haploidentical living-related grafts. All patients had presented with advanced disease, none had transplant nephrectomy, and all died of their disease. Between July 1988 and December 1990 (group 2), 362 transplants were performed, and four cases of M-PTLD and three cases of P-PTLD were recognized. Of the seven cases of PTLD in group 2, six developed within 90 days posttransplant (early PTLD). The mean time to development of PTLD was 11 +/- 16 weeks. This was significantly earlier than group 1 (P less than .01). Four of the five cases after KTxp had a 1 or 2 DR-matched donor. Five of these seven patients had serological evidence of recent Epstein-Barr Virus infection, and four of these five had received OKT3 and then developed early PTLD. In group 2, three patients are alive 7-15 months after KTxp nephrectomy, the remaining four have died. We hypothesize that risk factors for the development of PTLD may include heavy immunosuppression, including the use of OKT3, good DR matching, and active EBV infection. Treatment should include graft removal, if applicable, and reduction or cessation of immuno-suppression.

Regional adaptation of Müller cells in the chick retina. A Golgi and electron microscopical study.

We report the morphological differences of Müller cells in relation to their topography, using the Golgi method. Müller cells in the central retina are long and slender, with numerous inner prolongations. In the peripheral retina, the morphology of the Müller cells adapts to the reduced thickness of the retinal layers. In this zone, they are short and have thick inner prolongations which end in a large foot in the internal limiting membrane. In the optic disc margin, Müller cells have a particular morphology characterized by thick, arched prolongations that in general form a glial network between the retina and optic nerve. The ultrastructure of these cells is also described. The results are discussed with respect to the nature of Müller cells.

Two modes of cell migration in the ventral horn of the spinal cord in the chick embryo. A Golgi study.

The migration process of the ventral horn in chick embryo spinal cord cells has been studied between 2.5 and 5 days of incubation (HH-17, HH-26), using the Golgi technique. Two different migratory modes are observed. Type I--Migration by nucleus translocation. Most of the ventral horn motor neurons migrate by nucleus translocation within the peripheral cylinder of the cytoplasm (migration by nucleus translocation). Type II--Free migration cells. Other cells migrate disconnected from both limiting surfaces (ventricular and pial). On the basis of shape and migratory behaviour they have been identified as smooth cells and multipodial cells.

Displaced ganglion cells in the chick retina.

New morphological and cytological data on the displaced ganglion cells (DGCs) in the chick retina are presented. Analysis of the topographic distribution, cellular number, dendritic field, perikaryon size and ultrastructural characteristics are included. The DGCs were found predominantly in the peripheral retina. The sizes of the DGCs, 18-42 microns, observed either by Normarsky's interferential contrast or by silver impregnation techniques, spanned the size range of the other retinal neurons. The results support the hypothesis that DGCs, in the chick retina, may constitute a specific morphofunctional system, and therefore they might not be considered as neurons that fail to attain the normal location of ganglion cells during the developmental process of migration.

Amacrine cells with a rectilinear dichotomy of dendrites in the chick retina.

With Golgi impregnation, a simple amacrine cell type is described in the chick retina. The most relevant morphological feature of these retinal neurons is a single straight, radial trunk which dichotomizes tangentially in a rectilinear expansion in the 5th stratum of the inner plexiform layer (IPL).

Effects of ethanol on the inner layers of chick retina during development.

Optic nerve hypoplasia is an important malformation of the fetal alcohol syndrome whose teratogenic mechanisms are unknown. In our experimental model we have quantified the concentration of ethanol and acetaldehyde in the retina and vitreous humor of the developing chick. The effect of ethanol alone during retinal development was analyzed by conventional histological techniques and by immunostaining. A single injection of ethanol in the vitelline sac at the beginning of retinal cell differentiation retarded synaptogenesis in the inner plexiform layer and produced abundant ganglion cell death and a sharp diminution of myelinic axons. Our observations could help to explain certain alterations described in children exposed to ethanol during the development of their nervous system.

Hyperkalemic emergencies. Mechanisms, manifestations, and management.

Care of the patient with hyperkalemia provides the critical care nurse with a challenging opportunity to use clinical knowledge, skills, and critical thinking. What is the cause of the hyperkalemia? What are the patient's signs and symptoms? What clues do the patient's history and physical assessment hold? What treatments are necessary and how will their effectiveness be measured? Finally, how can subsequent episodes of hyperkalemia be prevented in this patient? Knowledge about potassium, its functions and its regulatory mechanisms provides the critical care nurse with the opportunity to identify patients at risk and employ early, often life-saving, interventions.

Continuous arteriovenous hemofiltration in the patient with hepatorenal syndrome. A case study.

CAVH has gained increasing medical acceptance, as favorable outcomes in the critically ill have proven its worth. Unfortunately, CAVH is often used as a "last ditch" effort for the patient with multisystem organ failure and septicemia. Performing the procedure in such a setting sometimes seems little more than an exercise in futility. However, as more patients such as the patient described in this case study are shown to benefit from CAVH, the nursing role needs to be examined both in performing the procedure and in caring for the critically ill patients. The nursing literature has kept abreast of the procedural aspects of CAVH. Now, critical care nurses must move on to the patient-oriented approach, share case studies, and work together to formulate nursing diagnoses, develop specialized care plans, and identify areas for nursing research.

Severe secondary hyperparathyroidism.

The process of managing SHPT requires ongoing evaluation and revision. Although A.M. presented a number of challenges in the course of managing her SHPT, the outcome goals were met. Throughout the course of treatment, the renal dietitian worked collaboratively with the other members of the multidisciplinary team and played an important role in educating the patient as well as monitoring the treatment plan and response to therapy. More aggressive paricalcitol dosing and close patient follow up was shown to be effective in the management of SHPT.

Renal physiology series: Part 1 of 8. Renal anatomy and overview of nephron function.

The kidneys are highly vascularized organs that are responsible for maintaining the body's internal environment. The nephron is the basic structural and functional unit of the kidney involved in the complex interplay between tubular and vascular components resulting in the excretion of fluid and solutes. The regulation of body fluid and solutes is governed by the processes of filtration, reabsorption, and secretion. Unwanted fluid and substances are excreted from the body as urine.

Case study: end stage liver failure patient managed with CAVH pretransplant.

The patient met 4 of the 5 expected outcomes. Effective therapy with CAVH was maintained in the ICU setting and in the operating room. The catheters functioned throughout the entire treatment without signs or symptoms of infection, bleeding, or thrombosis. She received hyperalimentation, filtration replacement fluid, and adequate fluid boluses to maintain volume status, nutritional requirements and vital signs. Cardiac vasopressor medications were required for a short period. The one problem that did occur was related to the anticoagulation therapy. The PTT was checked every 4 hours and the heparin drip was titrated to keep the PTT at 50 to 60 seconds. At one point, the PTT was 92 seconds but immediate measures were undertaken to reverse the condition. In the situation where a patient has an underlying coagulopathy and a potential source of bleeding, the nursing recommendation is that hourly bedside ACTs with every 4 hour PTTs should be performed as a routine part of the care. CRRT has been used successfully in critically ill unstable patients with multiorgan involvement. These therapies provide an avenue for collaboration between nursing professionals in nephrology and critical care. The focus of CRRT can now progress from the technical aspects of the procedures to patient centered nursing issues.

Case study of the anemic patient: epoetin alfa--focus on erythrokinetics.

Erythrokinetics is a physiologic process that regulates red blood cell dynamics. In keeping with the present trend of focusing on patient outcomes and costs, an erythrokinetic model provides a guideline for appropriate dosing of Epoetin alfa to maintain a hematocrit within the target range of 30% to 36%. Maintaining the patient's hematocrit at the optimal level influences patient outcomes by enhancing the quality of life and improving patient management by decreasing time and costs.

Alcoholism and brain damage: an investigation using the Luria-Nebraska Neuropsychological Battery.

Numerous neuropsychological tests have been used to assess the effects of chronic alcohol use on the brain. Recently, the introduction of the Standardized Luria-Nebraska Neuropsychological Battery has presented a fresh way of evaluating disorders due to brain dysfunction. The present paper is an investigation of deficits in alcoholics on the Luria-Nebraska Neuropsychological Battery. It was found that alcoholics differed from age--and education--matched controls on six of the fourteen scales of the test: Visual, Receptive Language, Arithmetic, Memory, Intelligence, and the Pathognomonic scale. An investigation of the individual items which differentiated alcoholics and controls found evidence that the effects of alcoholism are primarily seen in the more complex association areas of the brain, consistent with the conclusions reached by Gudeman and his associates. The implication and limitations of the present results were also discussed.

Pale and dark bipolar cells in the chicken retina.

Ultrastructurally, two different bipolar cell types can be distinguished in the retina of the chick embryo: one pale or electron-lucent and the other dark or electron-dense. The different electron density was seen over the whole cell, from its enclave in the outer limiting membrane to its termination in the inner plexiform layer. These observations prompted us to study the content and cytoplasmic variations of both cell types. The pale bipolar cell has a higher vacuole, vesicle and endoplasmic reticulum content and a lower number of microtubules and glycogen than the dark bipolar cell. The presence of these two cell types is probably due to a characteristic physiologic state, and the difference between the pale and dark bipolar cells can be attributed to the diverse number of gap unions which they establish with A II amacrine cells.

Liquid crystal domains and thixotropy of filamentous actin suspensions.

The thixotropic properties of filamentous actin suspensions were examined by a step-function shearing protocol. Samples of purified filamentous actin were sheared at 0.2 sec-1 in a cone and plate rheometer. We noted a sharp stress overshoot upon the initiation of shear, indicative of a gel state, and a nearly instantaneous drop to zero stress upon cessation of shear. Stress-overshoot recovery was almost complete after 5 min of "rest" before samples were again sheared at 0.2 sec-1. Overshoot recovery increased linearly with the square root of rest time, suggesting that gel-state recovery is diffusion limited. Actin suspensions subjected to oscillatory shearing at frequencies from 0.003 to 30 radians/sec confirmed the existence of a 5-min time scale in the gel, similar to that for stress-overshoot recovery. Flow of filamentous actin was visualized by polarized light observations. Actin from 6 mg/ml to 20 mg/ml showed the "polycrystalline" texture of birefringence typical for liquid crystal structure. At shear rates less than 1 sec-1, flow occurred by the relative movement of irregular, roughly ellipsoidal actin domains 40-140 microns long; the appearance was similar to moving ice floes. At shear rates greater than 1 sec-1, domains decreased in size, possibly by frictional interactions among domains. Eventually domains flow in a "river" of actin aligned by the flow. Our observations confirm our previous domain-friction model for actin rheology. The similarities between the unusual flow properties of actin and cytoplasm argue that cytoplasm also may flow as domains.

Psychiatric morbidity following implantation of the automatic implantable cardioverter defibrillator.

The automatic implantable cardioverter defibrillator (AICD) has found a place in the treatment of sustained ventricular tachycardia and in survivors of sudden arrhythmic death. However, little is known about the psychological impact of this device on patients and their families. In a group of 20 AICD recipients, examined between 3 and 21 months post-implantation, the prevalence of psychiatric disorder was 50%. Following implantation, six patients suffered from adjustment disorder; three suffered from major depression; and one developed panic disorder. Psychiatric morbidity in patients was associated with psychopathology in family members, peri-operative AICD shocks, and social support that was perceived to be inadequate.

Immunohistochemical localization of GABA in chameleon retina (Chamaleo Chamaleo).

We used a policlonal antiserum against GABA and demonstrated GABA-immunoreactivity (GABA-IR) in several populations of amacrine cells in the inner nuclear layer (INL), and other cells in the inner plexiform layer (IPL) of the central and peripheral retina of the chameleon. Horizontal cells do not contain GABA-IR and the chameleon retina is therefore an exception among non-mammals. GABA-IR was not seen in cell bodies in the position of photoreceptor, bipolar and interplexiform cells suggesting that GABA is not involved in synaptic transmission in the outer plexiform layer of chameleon retina.

Glutamine synthetase (GS) activity and spatial and temporal patterns of GS expression in the developing chick retina: relationship with synaptogenesis in the outer plexiform layer.

The profile of glutamine synthetase (GS) activity in the neural retina of chicken embryos and adults was studied alongside the in vivo spatio-temporal patterns of generation and morphogenesis of Müller cell and of retinal synaptogenesis. The rise of GS activity during development is not related to Müller cell differentiation but to synaptogenesis in the outer plexiform layer (opl). GS expression was investigated by immunoreaction with GS-specific antiserum. Three spatial gradients of decreasing labeling were observed between embryonic (E)15 and E18, from central to peripheral retina, dorsal to ventral, and temporal to nasal, which are in spatio-temporal relationship with synaptogenesis in the opl. GS is localized in Müller cells and apparently also in a population of astrocyte-like glial cells, located in the ganglion cell layer throughout the retina. Precocious induction by hydrocortisone, in ovo, at E10, does not show the spatial pattern of GS immunoreactivity observed in control retinas at the time of natural induction (E15). We also show that dissociated (non-cultured) Müller cells of E18-20 retinas, to which only photoreceptors or photoreceptors and neurons remain joined, maintain an immunodetectable level of GS, while those in isolated state lose GS immunoreactivity rapidly. Our results suggest that the induction of GS expression might be mediated by Müller cell-neuron interactions at the opl and also perhaps at the outer nuclear layer (onl). An analysis of our results and those of previous authors suggests that the level of GS in differentiated Müller cells could be determined by conjoint cell interactions at the onl, opl, and inner plexiform layer.

Complete heart block as a cause of syncope in asymmetric septal hypertrophy.

This case report presents a young adult with asymmetric septal hypertrophy (ASH) and syncope. Infranodal complete heart block was demonstrated as his cause for syncope. Therapy consisted of implantation of a A-V sequential pacemaker. Cardiac output determinations and systolic time intervals demonstrated the beneficial effects of properly timed atrial contractions.