Herpes Zoster Infection Following Solid Organ Transplantation: Incidence, Risk Factors and Outcomes in the Current Immunosuppressive Era

Herpes zoster (HZ) infection is a frequent and serious complication of organ transplantation that has not been examined in the current era of immunosuppression. All solid organ transplants performed between 1994 and 1999 (n = 869) at our center were analyzed to determine the incidence, complications and risk factors for developing HZ. The overall incidence of HZ was 8.6% (liver 5.7%, renal 7.4%, lung 15.1% and heart 16.8%). The median time of onset was 9.0 months. We observed high rates of cutaneous scarring (18.7%) and post-herpetic neuralgia (42.7%). Independent organ-specific risk factors included: female gender and mycophenolate mofetil therapy (liver), and antiviral treatment other than prolonged cytomegalovirus (CMV) prophylaxis (renal and heart). For all organs combined, induction therapy and antiviral treatment other than prolonged CMV prophylaxis were independent predictors for the development of HZ. Herpes zoster is common and results in significant morbidity for solid organ transplant recipients. Risk factors include induction therapy and antiviral drug therapy other than CMV prophylaxis. The latter variable identifies a subpopulation that is likely at increased risk of latent herpesvirus reactivation. The high first-year post-transplant incidence rate suggests immunization pretransplant, even in varicella zoster virus immunoglobulin seropositive individuals, may be preventative.     

Phase II trial of 4'-0-tetrahydropyranyladriamycin (pirarubicin) in head and neck carcinoma.

BACKGROUND. 4'-0-tetrahydropyranyladriamycin (Pirarubicin, Meiji Seika (USA) Inc., New York, NY) may be less toxic than doxorubicin. METHODS. A Phase II trial of Pirarubicin was done in 26 patients who had not previously had chemotherapy and who had measurable and incurable head and neck carcinoma. All patients received an intravenous bolus dose of 60 mg/m2 Pirarubicin in the first cycle without any prophylactic antiemetic. The cycles were repeated every 3 weeks. Based on tumor response, nadir counts, or complications of myelosuppression, the doses were escalated or de-escalated by 10 mg/m2, if necessary, in the second cycle to achieve mild leukopenia (3000-4000 leukocytes/microliters). RESULTS. Leukopenia was mild, moderate (2000-2999 leukocytes/microliters), severe (1000-1999 leukocytes/microliters), and life threatening (less than 1000 leukocytes/microliters) in 13%, 31%, 27%, and 9% of the first two courses, respectively. The median interval to nadir leukopenia was 13 days (range, 7-21 days), with a median of 8 days (range, 5-13 days) to recover to normal. One patient with a leukocyte count of 800/microliters and an absolute granulocyte count (AGC) of 488/microliters died of sepsis 15 days after the first course. All patients had at least one course that resulted in leukopenia. One episode each of mild (100,000-150,000 platelets/microliters) and severe (25,000-49,999 platelets/microliters) thrombocytopenia occurred in the first two courses. Leukocyte, granulocyte, and platelet counts were not done routinely after the second cycle. Six patients who received four or more courses with cumulative doses of 310, 610, 340, 260, 660, and 550 mg/m2 had decrements of 0%, 1%, 7%, 10%, 12%, and 13%, respectively, in radionuclide left ventricular ejection fraction (LVEF). All other toxic effects were mild. CONCLUSIONS. In the 24 patients with disease evaluable for response to Pirarubicin therapy, 1 had a complete response that lasted 5 months and 4 had a partial response of 2, 3, 6, and 8 months. The median survival time in patients with disease that responded to Pirarubicin therapy was 27 months; in patients with disease that did not respond to Pirarubicin therapy, the median survival time was 4 months, and in the total cohort, it was 5 months. Pirarubicin was well tolerated and was an active agent in head and neck squamous cell carcinoma.     

Novel diketopiperazine enhances motor and cognitive recovery after traumatic brain injury in rats and shows neuroprotection in vitro and in vivo.

The authors developed a novel diketopiperazine that shows neuroprotective activity in a variety of in vitro models, as well as in a clinically relevant experimental model of traumatic brain injury (TBI) in rats. Treatment with 1-ARA-35b (35b), a cyclized dipeptide derived from a modified thyrotropin-releasing hormone (TRH) analog, significantly reduced cell death associated with necrosis (maitotoxin), apoptosis (staurosporine), or mechanical injury in neuronal-glial cocultures. Rats subjected to lateral fluid percussion-induced TBI and then treated with 1 mg/kg intravenous 35b thirty minutes after trauma showed significantly improved motor recovery and spatial learning compared with vehicle-treated controls. Treatment also significantly reduced lesion volumes as shown by magnetic resonance imaging, and decreased the number of TUNEL-positive neurons observed in ipsilateral hippocampus. Unlike TRH or traditional TRH analogs, 35b treatment did not change mean arterial pressure, body temperature, or thyroid-stimulating hormone release, and did not have analeptic activity. Moreover, in contrast to TRH or typical TRH analogs, 35b administration after TBI did not alter free-magnesium concentration or cellular bioenergetic state. Receptor-binding studies showed that 35b did not act with high affinity at 50 classical receptors, channels, or transporters. Thus, 35b shows none of the typical physiologic actions associated with TRH, but possesses neuroprotective actions in vivo and in vitro, and appears to attenuate both necrotic and apoptotic cell death.     

Development of Diabetes Mellitus Following Kidney Transplantation: A Canadian Experience

The onset of diabetes mellitus following kidney transplantation or post-transplant diabetes mellitus (PTDM) is now recognized as being an increasingly common complication that is associated with poor graft and patient survival. The incidence and clinical correlates of PTDM in a Canadian kidney transplant population has not been examined and may vary based on differences in demographics (i.e. race). Furthermore, little information exists on the association of variables such as cumulative dose of corticosteroids and trough calcineurin inhibitor levels and PTDM. We examined all recipients of a kidney transplant in our center between 1995 and 2001 and found an overall PTDM rate of 9.8%. Five clinical factors were independently associated with PTDM: older recipient age, deceased donor, hepatitis C antibody status, rejection episode and use of tacrolimus (vs. cyclosporine). Furthermore, cumulative corticosteroid dose and calcineurin inhibitor trough level were not associated with PTDM. This study demonstrates that in a Canadian kidney transplant population that there is a significant risk of PTDM following kidney transplantation, and it is therefore advisable to minimize this risk.     

Renal excretion of stevioside in rats.

The renal excretion of stevioside, a glycoside extracted from the leaves of Stevia rebaudiana, and its effect on renal excretion of several substances, was studied through clearance techniques in Wistar rats. After a control period, stevioside was infused iv at four concentrations (4, 8, 12, and 16 mg/kg). During all the experiments no significant changes in inulin clearance (CIn) were observed. The stevioside infusion induced a significant increase in the p-aminohippuric acid clearance (CPAH), fractional sodium excretion (FeNa+), urinary flow as percent of glomerular filtration rate (V/GFR), and glucose clearance (CG) when compared to controls, but these effects were absent with the dose of 4 mg/kg. The stevioside clearance (CS) was higher than the CIn and lower than the CPAH at all the doses employed in this study. These results indicate that the stevioside is secreted by renal tubular epithelium and induces diuresis and natriuresis and a fall in renal tubular reabsorption of glucose.     

Visual and somatosensory information to tongue motoneurons

The experiments were designed to show whether visual inputs and somatosensory signals travelling along the common radial nerves converge onto the same hypoglossal neurons. The hypoglossal neurons (HN) type I (45.77%) and II (33.89%) responded to both visual and somatosensory stimuli. The HN type III (15.26%) responded only to the retinae and type IV (5.08%) only to the forelimb nerves stimulation. In the convergent neurons, types I and II, the influence of the somatosensory stimulation on the hypoglossal visual response was also analyzed. The conditioning stimulation of the radial nerve significantly increased (31%) the hypoglossal response to the less effective retina and significantly reduced (17%) the response to the more effective retina. The recordings of the electromyographic activity of the genioglossus (GM) and the superior longitudinal muscle (SLM), showed that the somatosensory afferents synergize the excitatory effect of the visual messages on the extrinsic tongue muscles (GM) and antagonize the inhibitory effect that visual messages induce on the intrinsic tongue muscles (SLM). The results suggest that visual messages induce tongue reflex responses functionally directed not only to prepare the oral cavity better for food reception, as previously demonstrated, but also to modulate the postural tone of the tongue together with somatosensory signals.     

Increased cognitive sensitivity to scopolamine with age and a perspective on the scopolamine model

18 older normal volunteers (mean age = 66.5 ± 7.9 years) and 46 younger volunteers (mean age = 27.0 ± 6.1 years) were administered the anticholinergic drug scopolamine (0.5 mg i.v.) followed by a battery of cognitive tests evaluating attention, learning and memory. The older subjects were significantly more impaired than the younger by scopolamine on some tests of learning and memory. This increased sensitivity of the older group to scopolamine is consistent with studies in animals and humans showing decreased cholinergic system function with age. The findings also indicate that age is an important variable to consider in using the scopolamine model of memory impairment. The cognitive impairment caused by scopolamine in younger subjects in this and prior studies is similar to some, but not all aspects of the impairment which occurs in normal aging^11,29,37. Scopolamine also caused impairments on digit span and word fluency tasks, which are not consistent with normal aging changes. In the older group of subjects, scopolamine produced aspects of the cognitive impairment which occurs in AD on tests of episodic memory and learning, vigilance-attention, category retrieval, digit span, and number of intrusions^64,86,88,91. Other areas of cognition that are of relevence to aging and AD such as psychomotor speed, praxis, concept formation and remote memory were not evaluated in this study. Some of these are being evaluated in ongoing studies, along with additional and more specific tests of retrieval from knowledge memory, implicit memory and attention. The scopolamine model has provided a fruitful pharmacologie starting point for the study of a number of cognitive operations. The idea of dissecting apart aspects of memory systems pharmacologically depends on the availability of neurochemically specific drugs and on the specificity and sensitivity of neuropsychological tests for distinct cognitive operations or domains. Further studies using such tools will aid not only in the understanding of the impairments which occur in aging and in AD, but also of the conceptualization of memory and other cognitive operations and ultimately the physiological mechanisms involved in memory and learning.     

Spatial-temporal interactions in the steady-state pattern electroretinogram

It is currently assumed that steady-state pattern electroretinograms can be obtained only at high rates of pattern reversal. However, steady-state responses can also be obtained at very low temporal frequencies (less than 1 Hz), provided that the reversal is sinusoidal. In five healthy volunteers, we studied the frequency characteristics of the pattern-reversal electroretinogram in response to sinusoidal gratings of 0.4 and 4 c/deg, reversed sinusoidally in contrast at frequencies ranging from 1 to 27 Hz. Steady-state responses dominated by the second harmonic component were obtained at all temporal frequencies tested; the amplitude of the second harmonic changed with stimulus temporal frequency. In the low-temporal-frequency range, stimuli of high spatial frequency appear to elicit larger contribution of generators with sustained or tonic characteristics compared with stimuli of low spatial frequency.     

Triiodothyronine Regulates Insulin-Like Growth Factor-I Binding to Cultured Rat Pituitary Cells*

Triiodothyronine (T₃) stimulates the synthesis of growth hormone and enhances the growth of neoplastic rat pituitary somatomam-motrophs (GH cells) in culture. Moreover, T₃ has been shown to stimulate the production and secretion of an autocrine growth factor by these cells. We have previously demonstrated the presence of specific receptors for insulin-like growth factors (IGF) on GH cells. Since GH₃ cells contain mRNA encoding IGF-I, it has been suggested that IGF-I might act in an autocrine fashion in these cells. Therefore, it was of interest to learn how T₃ affects IGF-I binding to GH₃ cells. T₃ increased [¹²⁵I]IGF-I binding in a time - and dose-dependent manner. After 48 h of exposure to T₃, an increase in IGF-I binding was seen with 10^?11M T₃, maximizing with 10^?8M T₃. When cells were exposed to 10^?8 T₃, [¹²⁵I]IGF-I binding reached a maximum of 218 ± 20.8% of control (±SEM, P < 0.002) after 72 h of incubation. Scatchard analysis indicated that T₃ did not alter the K_d of IGF-I for its receptor, but that the total receptor number was increased. Dexamethasone (10^?7M) inhibited the T₃-induced increase in IGF-I binding, but glucocorticoid alone did not substantially alter receptor number. No significant change in insulin or IGF-II binding was seen after hormone treatment. 10^?8 M T₃ or IGF-I increased the growth of the GH₃ cells by ≥30%. Our data indicate that T₃ upregulates IGF-I binding in GH₃ cells without altering insulin binding and thereby provides a means for enhancing potential autocrine regulation in this cell line.