A possible role for p16INK4 in neuronal cell death after retinal ischemia-reperfusion injury

PURPOSE: To study whether cell type-specific death occurs in retinal ischemia-reperfusion injury and the possible roles of p16INK4 in the determination of cell death. METHODS: Retinal ischemia-reperfusion injury was induced in rats by a ligation method. After 1 hour of ischemia and a time of reperfusion that varied, rat eyes were enucleated. Cell death in the retina was studied by the TdT-dUTP terminal nick-end labeling method and propidium iodide (PI) staining. Electron microscopic observation of the retina was also performed. Immunohistochemical studies using antibodies against syntaxin and calbindin were performed to detect amacrine cells and horizontal cells, respectively, and immunohistochemical studies using an antibody against p16INK4 were performed to study whether this cell cycle-related protein was expressed in dying cells. RESULTS: Most of the calbindin-positive horizontal cells in the outer aspect of the inner nuclear layer (INL) showed morphologic features of necrosis. In contrast, syntaxin-positive amacrine cells in the inner aspect of the INL showed features of apoptosis. Of 320 calbindin-positive horizontal cells, only 11 (3.4%) showed positive PI staining. Those calbindin-positive, horizontal cells were p16INK4 positive. In contrast, 746 of 910 (82.0%) syntaxin-positive amacrine cells showed condensed PI staining, and none were p16INK4 positive. CONCLUSIONS: Expression of p16INK4 may regulate the fate of retinal neurons in ischemia-reperfusion injury, and cell type-specific death thus occurs in the retina after such injury.     

Color from motion: dichoptic activation and a possible role in breaking camouflage

'Color from motion' describes the perception of a spread of subjective color over achromatic regions seen as moving. The effect can be produced in a display of multiple frames shown in quick succession, each frame consisting of a fixed, random placement of colored dots on a high-luminance white background with color assignments of some dots, but not dot locations, changing from frame to frame. Evidence is presented that the perception of apparent motion and the spread of subjective color can be activated by binocular combination of disjoint signals to each eye. The dichoptic presentation of every odd-numbered frame of the full stimulus sequence presented to one eye and, out of phase, every even-numbered frame to the other eye produces a compelling perception of color from motion equal to that seen with the full sequence presented to each eye alone. This is consistent with the idea that color from motion is regulated in sites at or beyond the convergence of monocular pathways. When the background field in the stimulus display is of low luminance, an amodally complete object, fully colored and matching the dots defining the moving region in hue and saturation, is seen to move behind a partially occluding screen. Observers do not perceive such an object in still view. Hence, color from motion can be used by the visual system to produce amodal completion, which suggests that it may play a role in enhancing the visibility of camouflaged objects.     

Minimal residual disease after allogeneic bone marrow transplantation for chronic myeloid leukaemia: a metaphase-FISH study

Metaphase-FISH was adopted for the detection of proliferating Philadelphia-positive (Ph+) residual leukaemic cells in 25 patients with chronic myeloid leukaemia treated with allogeneic bone marrow transplantation (BMT). Patients were followed up during their clinical remission for 4-50 months (median 17 months) after BMT. 80 bone marrow samples were studied. For most of the cases no fewer than 1000 metaphases were analysed. Six patients (24%) showed residual Ph+ cells during the first 6 months and two others by the end of the first year after BMT. Three patients relapsed during the study and in two of them residual Ph+ cells were detected during the first 6 months after BMT. In 17 patients no Ph+ cells were detected at any stage of follow-up and 16 (94.1%) of them continue in complete clinical and haematological remission. Our results indicate that metaphase-FISH is a reliable tool in the quantitation of proliferating residual leukaemic cells. We suggest that consecutive findings of equal amounts of residual leukaemic cells do not necessarily predict a relapse. However, their presence calls for follow-up at shorter intervals where an increasing number of these cells predicts an ensuing relapse.     

Receptive field changes after strokelike cortical ablation: a role for activation dynamics

The reorganization of neural activity that takes place after stroke is of paramount importance in producing functional recovery. Experimental stroke models have suggested that this reorganization may have two phases, but physiology alone cannot fully resolve what causes each phase. Computer modeling suggests that these phases might involve an initial change in dynamics occurring immediately, followed by synaptic plasticity. We combined physiological recording from macaque middle temporal cortex (area MT) with a neural network computer model to examine this first phase of altered cortical function after a small, experimentally induced cortical lesion. Major receptive field (RF) changes seen in the first few days postlesion included both expansion and contraction of receptive fields. Although only expansion could be reproduced in an initial model, addition of inhibitory interneuron loss in a ring around the primary ablation, suggested by immunohistochemical examination, permitted contraction to be replicated as well. We therefore predict that this immunochemical observation reflects an immediate extension of the lesion rather than a late response. Additionally our model successfully predicted a correlation between increased firing rate and RF size. Our model suggests that activation dynamics alone, without anatomic remodeling, can cause the large receptive field changes that allow the rapid behavioral recovery seen after middle temporal lesions.     

Squamous cell carcinomas after allogeneic bone marrow transplantation for aplastic anemia: further evidence of a multistep process

Two new potent serine protease inhibitors, cyclotheonamides E2 (3) and E3 (4), have been isolated from a marine sponge of the genus Theonella. Their structures were determined by interpretation of spectral data and chemical degradation studies. They are closely related to the previously reported cyclotheonamide E, from which they differ in the N-acyl group of the alanyl side chain. Cyclotheonamides E, E2, and E3 were more active against thrombin than against trypsin.     

Norethisterone treatment, a major risk-factor for veno-occlusive disease in the liver after allogeneic bone marrow transplantation

In this single-center study, we retrospectively analyzed incidence and risk factors for hepatic veno-occlusive disease (VOD) in 249 consecutive patients who underwent allogeneic hematopoietic stem cell transplantation between January 1990 and June 1995. Twenty-four of the 249 transplanted patients developed VOD. The probabilities of developing VOD were 17% among women and 7% in men (P =.01). In women treated with norethisterone, the incidence was 27% compared with 3% in women without this treatment (P =.007). One-year survival rates were 17% and 73% in patients with (n = 24) or without VOD (n = 225), respectively. The use of heparin prophylaxis (100 IE/kg/24 hours for 1 month) did not alter the incidence or 1-year mortality of VOD. In multivariate analysis, the following risk factors were significant: norethisterone treatment (P <.001), bilirubin >26 micromol/L before bone marrow transplantation (BMT) (P =.002), one HLA-antigen mismatch (P =.003), previous abdominal irradiation (P =.02), and conditioning with busulphan (P =.02). Our conclusion is that norethisterone treatment should not be used in patients undergoing BMT and heparin prophylaxis did not affect the incidence or mortality of VOD.     

Increased fat intake during lactation modifies hypothalamic-pituitary-adrenal responsiveness in developing rat pups: a possible role for leptin

High fat feeding reportedly enhances hypothalamus-pituitary-adrenal (HPA) responses to stress in adult rats. The present study tested whether elevated fat intake during suckling could have short and/or long lasting consequences on HPA regulation in the offspring. Mothers were fed either a control (C; 5% fat) or high fat (HF; 20% fat) diet during the last week of gestation and throughout lactation. After weaning (day 21), pups from C and HF mothers were fed a chow diet. Offspring from both C- and HF-fed mothers were tested for ACTH and corticosterone responses to stress on postnatal days 10 and 35. We found that HF feeding produced higher lipid levels in the milk of HF compared with C lactating rat dams and that offspring of these mothers had significantly increased retroperitoneal fat pad weight and relative adipose mass on day 21 as well as elevated plasma leptin levels on days 10 and 21 of age. After weaning, pups from the HF mothers had lower plasma leptin levels than those from C mothers. Maternal dietary fat affected HPA responsiveness in the offspring in an age-related manner. Neonatal pups (day 10) from the HF mothers exhibited a reduction in the ACTH and corticosterone responses to ether stress. However, in 35-day-old offspring from HF-fed dams, stress-induced ACTH secretion was increased compared with that in pups from the C-fed mothers. These results demonstrate that maternal diet and increased fat intake through the milk are important regulators of HPA responsiveness in neonates and prepubertal rats. During neonatal life, the blunted stress responsiveness seen with elevated fat intake and the resulting high leptin levels might protect the pups from excessive HPA activation. After removal of the maternal dietary influence and reduced leptin levels, enhanced ACTH stress responses are observed as in adult rats fed a HF diet. Because of the inverse relationship between plasma levels of leptin and HPA responses in pups, the possibility exists that the effects of the HF diet on stress responsiveness are mediated by changes in leptin exposure during development.     

Human herpesvirus-6 meningoencephalitis in a recipient of an unrelated allogeneic bone marrow transplantation

BACKGROUND: Human herpesvirus-6 (HHV-6) has been implicated in bone marrow suppression, interstitial pneumonitis, and fatal meningoencephalitis in bone marrow transplant (BMT) recipients. METHODS: We describe the case of a woman with acute myeloid leukemia in second remission who developed febrile meningoencephalitis 8 months after a second unrelated BMT. RESULTS: Computed tomography and magnetic resonance images of the brain were nonspecific. Analysis of cerebrospinal fluid (CSF) revealed lymphocytosis and an increased protein level. Using polymerase chain reaction methods, HHV-6 was the only pathogen detected in CSF, peripheral blood mononuclear cells, and bone marrow. The patient was treated with ganciclovir and foscarnet for 3 months. All clinical manifestations resolved and HHV-6 polymerase chain reaction analysis of CSF became negative 40 days after the beginning of antiviral treatment. CONCLUSIONS: This observation strongly suggests that HHV-6 should be sought in BMT patients with neurological complications and that HHV-6 meningoencephalitis may respond to ganciclovir and foscarnet therapy.     

Risk factors for death after heart transplantation: does a single-center experience correlate with multicenter registries?

BACKGROUND: Risk factors for death after heart transplantation (Tx) are frequently documented from multicenter registries. Although this information is helpful, it reflects a whole range of experiences and results, and may not translate to a particular center. This study was performed to (1) evaluate pre-Tx factors affecting mortality in a single-center experience, and (2) compare these factors with risk factors obtained from multicenter registry reports. METHODS: Review of our transplant database between January 1984 and December 1995 identified 405 adults who received a primary heart Tx. Multiple factors were analyzed, including demographics, Tx era, cytomegalovirus status, United Network for Organ Sharing status of recipient, presence of pulmonary hypertension, previous cardiac operations, mechanical ventilation or circulatory support, ischemia time, number of rejection episodes, and preoperative flow cytometry crossmatching. RESULTS: One- and 5-year survival rates were 87.8% and 73.4%, respectively (Kaplan-Meier). Contrary to multicenter registry reports, our data indicate that reoperative procedures, left ventricular assist device support, increasing donor and recipient age, and ischemia time up to 4.2 hours are not risk factors for death after Tx. Likewise, mode of donor death is not a risk factor affecting outcome. Significant risk factors for mortality identified by multivariate analysis included early transplant era (1984 to 1989; p = 0.002), female donor (p = 0.042), cytomegalovirus-seropositive donor (p = 0.048), high pulmonary vascular resistance (p = 0.018), and intraaortic balloon pump support (p = 0.03). It also identified a positive B-cell flow cytometry crossmatch (p = 0.015) to be a risk factor with univariate analysis. CONCLUSIONS: Our data identify a group of recipients, reportedly at high risk in multicenter registries, who are not at increased risk of death after Tx. This information supports the growing experience with older donors and recipients and with bridged transplants, and has allowed us to expand our donor pool. These prognostic factors at evaluation allow more liberal selection of patients and donors for transplantation.     

Fatal interstitial pulmonary disease in a patient with dyskeratosis congenita after allogeneic bone marrow transplantation

Local control rate by radical radiation therapy was analyzed in 33 patients with a piriform sinus cancer. Twenty-five patients (76%) were in stage T3 + T4. Local recurrence-free survival at 3 years was 49% in T1 + T2 and 25% in T3 + T4 (p = 0.01). In T1 + T2 lesions, a biologically effective dose for an acute reaction over 80 Gy and total treatment time less than 70 days appeared to improve local control. In T3 + T4 lesions, good radiation response assessed by the regaining of laryngeal mobility affected local control favorably. An esophageal involvement and destruction of the laryngeal cartilage as well as soft tissue extension precluded the possibility of local control by radiation therapy alone. In addition to the T-stage, other tumor factors should also be considered for predicting local control with radiation therapy.     

Granulocytic sarcoma after allogeneic bone marrow transplantation: a retrospective European multicenter survey. Acute and Chronic Leukemia Working Parties of the European Group for Blood and Marrow Transplantation

In the newly established rat sarcoma cell line LSR-SF (SR) expression of pp60v-src was detected. Karyotype analyses revealed various chromosome aberrations during prolonged passaging of the tumor cells in vitro. Polyploidy was found to be a characteristic feature of the line studied. A large metacentric chromosome persistently present in the cells was accepted as a line marker.     

Salvage autologous or allogeneic transplantation for multiple myeloma refractory to or relapsing after a first-line autograft?

The authors examined the effects of cognitive function, as assessed by the Mini-Mental State Examination, and drug use on the incidence of hip fracture in a community-based Swedish population of 1,608 subjects who were aged > or = 75 years on October 1, 1987, and who had not had a hip fracture. During the 7,123.8 person-year follow-up, 134 first hip fractures were identified. The Cox proportional hazards model was used to estimate the relative risk of developing hip fracture, taking into account several potential confounders. Compared with those without cognitive impairment, subjects with mild impairment (Mini-Mental State Examination scores 18-23) had a relative risk of 2.04 (95% confidence interval (CI) 1.29-3.24), and subjects with moderate-severe impairment (Mini-Mental State Examination score < 18) had a relative risk of 2.09 (95% CI 1.17-3.72). Subjects using opioid analgesics (97% took propoxyphene) had a relative risk of 2.01 (95% CI 1.19-3.40). Taking potassium supplements (99% took potassium chloride) was related to a reduced risk of hip fracture (relative risk = 0.55, 95% CI 0.31-0.98), while diuretics did not have an independent impact. In summary, the results show that cognitive impairment and use of propoxyphene are associated with increased risk of hip fracture. The observed protection of potassium chloride merits further attention. The limitation of the study was that the assessment of drug use was made only at baseline.     

Neuronal death: is there a role for astrocytes?

Astrocytes are ubiquitous in the brain and have multiple functions. It is becoming increasingly clear that they play an important role in monitoring the neuromicroenvironment in CNS and in information processing or signaling in the nervous system in normal conditions and respond to CNS injuries in a gradual and varied way. It is still debated whether such reactions are beneficial or detrimental. It was believed that reactive astrogliosis observed in most neurological disorders may regulate the removal of toxic compounds produced by damaged neurons and support neuronal growth by releasing trophic factors. However it was also suggested that astrocytes contribute to a decline of neurologic function, for example by accumulation and release of excitotoxic aminoacids after ischemia and oxidative stress, formation of epileptogenic scars in response to CNS injury and metabolism of protoxins to potent toxins. In a number of metabolic diseases astrocytes, not neurons, may be the primary target. The astrocyte's role in normal and pathological conditions will be discussed in the light of recent information about their metabolism, receptor distribution and release.     

A role for perforin in activation-induced T cell death in vivo: increased expansion of allogeneic perforin-deficient T cells in SCID mice

Despite defective granule exocytosis, T cells from mice whose perforin gene was ablated by homologous recombination (pko mice) caused a similar degree of graft-vs-host disease as normal T cells after injection into sublethally irradiated C.B-17 SCID mice. Moreover host spleens contained significantly greater numbers of T cells from pko mice than from wild-type mice following their i.v. injection. This increase could not be explained by persistence of host APCs that were not cleared by defective donor cytotoxic effector cells. The absence of functional perforin-dependent suppressor cells or an altered cytokine profile of donor T cells could also not account for the behavior of pko cells. Spontaneous and Fas-mediated apoptosis of in vivo activated donor T cells were independent of donor origin. However, pko T blasts exhibited less growth inhibition and cell death after reactivation in vitro. The results are compatible with a model of a defective activation-induced cell death (AICD) pathway, controlled by perforin, accounting for the increased expansion of alloreactive pko T cells.     

Bronchiolitis obliterans organizing pneumonia and chronic graft-versus-host disease in a child after allogeneic bone marrow transplantation

BACKGROUND: Human immunodeficiency virus type 1 (HIV-1) subtype O infections are not reliably detected by commonly used anti-HIV-1/2 screening assays. Therefore, anti-HIV-1/2 assays have been modified to increase their sensitivity in detecting antibodies to HIV-1 subtype O. STUDY DESIGN AND METHODS: Two new anti-HIV-1/2 enzyme-linked immunosorbent assays (ELISAs) (Abbott Plus and Ortho Enhanced) were compared with a currently used anti-HIV-1/2 ELISA (Abbott Recombinant) in various serum panels: 91 Western blot-confirmed anti-HIV-1-positive samples, 20 samples from Western blot-confirmed HIV-1-infected patients in log3 serial dilutions, and 1463 samples from consecutive, volunteer, nonremunerated blood donors. RESULTS: Among 91 anti-HIV-1 Western blot-positive samples, 2 (2.2%) were missed by the Abbott Recombinant ELISA, but all 91 were detected by the Abbott Plus and Ortho Enhanced ELISAs. In contrast, two discrepant samples were found to react in viral lysate-based assays. In serial dilutions, Ortho Enhanced ELISA was significantly less sensitive than the Abbott Recombinant and Abbott Plus ELISAs, with the latter two being of comparable sensitivity. The specificities of Abbott Recombinant, Abbott Plus, and Ortho Enhanced ELISAs in 1463 blood donors were 100, 99.93, and 99.86 percent, respectively. Routine testing of 29,102 donations with the enhanced Abbott Plus ELISA revealed a specificity of 99.93 percent. CONCLUSION: Two Western blot-confirmed anti-HIV-1-positive samples were missed by the Abbott Recombinant ELISA but detected by the Abbott Plus and Ortho Enhanced ELISAs. The analytic sensitivity of the Ortho Enhanced ELISA was inferior to that of both Abbott ELISAs. The specificities of the Abbott Recombinant, Abbott Plus, and Ortho Enhanced ELISAs were comparable.