Subanaesthetic ketamine and altered states of consciousness in humans.

BACKGROUND: Despite its designation as a 'dissociative anaesthetic,' the dissociative and psychoactive effects of ketamine remain incompletely understood. The goal of this study was to characterise the subjective experiences and accompanying EEG changes with subanaesthetic doses of ketamine. METHODS: High-density EEG was recorded in 15 human volunteers before, during, and after subanaesthetic ketamine infusion (0.5 mg kg-1 over 40 min), with self-reported measures of altered states of consciousness obtained after ketamine exposure. Sensor- and source-level EEG changes were analysed with a focus on spectral power and regional changes. RESULTS: Ketamine-induced altered states were characterised predominantly by dissociative experiences such as disembodiment and ego transcendence; sensory disturbances were also common. Ketamine broadly decreased low-frequency power, with mean reductions largest at alpha (8-12 Hz) in parietal (-0.94 dB, P<0.001) and occipital (-1.8 dB, P<0.001) channel clusters. Significant decreases in alpha were identified in the precuneus and temporal-parietal junction. CONCLUSIONS: Ketamine induces altered states of consciousness during periods of reduced alpha power in the precuneus and temporal-parietal junction. Modulation of these temporal-parietal loci are candidate mechanisms of the psychoactive effects of ketamine, given that this region is involved in multisensory integration, body representation, and consciousness.

Investigating Tissue Regeneration Using the DUAL Control Genetic Ablation System.

Genetic ablation is a highly efficient method to study regeneration in vivo by stimulating tissue-specific cell death that subsequently induces regrowth and repair in a developing organism. This approach has been particularly successful in Drosophila, for which various temperature-based genetic ablation tools have been developed to explore the complexities of regeneration in larval imaginal discs. Here, we describe the use of a recently established ablation system called DUAL Control, which can be used to both characterize the damage response and genetically manipulate blastema cells to identify novel regulators of regeneration.

Cyclooxygenase-2 (cox-2) blockade in the chemoprevention of cancers of the colon, breast, prostate, and lung.

The existing epidemiologic literature was comprehensively reviewed to retrieve all epidemiologic studies (case control and cohort studies) that examined exposure to traditional over the counter nonsteroidal anti-inflammatory drugs (OTC NSAIDs) and the risk of cancers of the colon, breast, prostate and lung from 1980 forward. These malignancies account for more that half of all cancer deaths in the United States and the United Kingdom. Estimates of effects (relative risks or odds ratios) and 95% confidence intervals were abstracted from these reports for meta-analysis. Regular intake of OTC NSAIDs produced highly significant composite risk reductions of 43% for colon cancer, 25% for breast cancer, 28% for lung cancer, and 27% for prostate cancer. Furthermore, in a series of case control studies, daily use of a selective COX-2 inhibitor, either celecoxib or rofecoxib, significantly reduced the risk for each of these malignancies. The evidence is compelling that anti-inflammatory agents with selective or non-selective activity against cycloooxygenase- 2 (COX-2) have strong potential for the chemoprevention of cancers of the colon, breast, prostate and lung. Results confirming that COX-2 blockade is effective for cancer prevention have been tempered by observations that some selective COX-2 inhibitors pose a risk to the cardiovascular system. Nevertheless, meta-analysis of independent estimates from 72 studies provides no evidence that the selective COX-2 inhibitor, celecoxib, influences the relative risk of cardiovascular disease (composite relative risk = 0.98, 95% CI = 0.88-1.10). Molecular studies reveal that over-expression of COX-2 is a prominent feature of premalignant and malignant neoplasms. Evidence is accumulating that carcinogenesis often evolves as a progressive series of highly specific cellular and molecular changes in response to induction of constitutive over-expression of COX-2 and the prostaglandin cascade in the "inflammogenesis of cancer".

Reduced-intensity conditioning is effective and safe for transplantation of patients with Shwachman-Diamond syndrome.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only potentially curative treatment for the BM dysfunction seen in patients with Shwachman-Diamond syndrome (SDS). Historically, these patients have fared poorly with intensive conditioning regimens with increased regimen-related toxicity especially involving the heart and lungs. We report our institutional experience with a reduced-intensity-conditioning protocol in seven patients with SDS and BM aplasia or myelodysplastic syndrome/AML. The preparative regimen consisted of Campath-1H, fludarabine and melphalan. Four patients received matched related marrow and three received unrelated stem cells (two PBSCs and one marrow). All but one was 8 of 8 allele HLA matched. All patients established 100% donor-derived hematopoiesis. No patient in this cohort developed grades III-IV GVHD. One patient had grade II skin GVHD that responded to systemic corticosteroids and one had grade I skin GVHD, treated with topical corticosteroids. Two out of seven patients developed bacterial infections in the early post transplant period. Viral infections were seen in four out of seven patients and were successfully treated with appropriate antiviral therapy. All patients are currently alive. These data indicate that HSCT with reduced-intensity conditioning is feasible in patients with SDS and associated with excellent donor cell engraftment and modest morbidity.

GABA-from Inhibition to Cognition: Emerging Concepts.

Neural functioning and plasticity can be studied on different levels of organization and complexity ranging from the molecular and synaptic level to neural circuitry of whole brain networks. Across neuroscience different methods are being applied to better understand the role of various neurotransmitter systems in the evolution of perception and cognition. GABA is the main inhibitory neurotransmitter in the adult mammalian brain and, depending on the brain region, up to 25% of the total number of cortical neurons are GABAergic interneurons. At the one end of the spectrum, GABAergic neurons have been accurately described with regard to cell morphological, molecular, and electrophysiological properties; at the other end researchers try to link GABA concentrations in specific brain regions to human behavior using magnetic resonance spectroscopy. One of the main challenges of modern neuroscience currently is to integrate knowledge from highly specialized subfields at distinct biological scales into a coherent picture that bridges the gap between molecules and behavior. In the current review, recent findings from different fields of GABA research are summarized delineating a potential strategy to develop a more holistic picture of the function and role of GABA.

Breast cancer risk: effects of estrogen replacement therapy and body mass.

BACKGROUND: Epidemiologic studies have focused on the association between breast cancer risk and a variety of lifestyle and exogenous factors. PURPOSE: The purpose of this study was to clarify the effects of alcohol consumption, cigarette smoking, oral contraceptive (OC) use, estrogen replacement therapy (ERT), and body mass on risk of breast cancer. METHODS: These variables were examined in a case-control study of 604 patients with newly diagnosed breast cancer and 520 control subjects who did not have breast cancer and were frequency matched for age, hospital, and time of diagnosis. These case patients and control subjects were part of an ongoing study of breast cancer by the American Health Foundation and were selected for interview from hospitals in the New York City area from January 1987 through December 1989. The data were analyzed by computation of odds ratios (ORs) for potential risk factors, with adjustment for age at diagnosis and other potential confounding variables and with stratification by menopausal status. RESULTS: We observed positive effects of ERT and high body mass on the risk of postmenopausal breast cancer, particularly when each factor was examined in the absence of the other factor. In lean postmenopausal women, the adjusted summary OR associated with ERT was significantly elevated (OR = 2.0; 95% confidence interval [CI] = 1.1-3.5; P < .01), and there was a statistically significant dose response of breast cancer risk with ERT duration (adjusted ORs = 2.0 for < 5 years and 2.2 for > or = 5 years; positive trend, P < .02). Reciprocally, in women who did not receive ERT, high body mass (Quetelet index > 27) was a significant risk factor for postmenopausal breast cancer (OR = 2.1; 95% CI = 1.3-3.3; P < .02), and the linear trend in risk with increasing body mass was significant (positive trend, P < .02). The strongest effect of body mass occurred in women who were lean at age 18 and gained enough weight to place them in the upper tertile of body mass at the time of diagnosis (OR = 2.6; 95% CI = 1.5-4.6; P < .01). There was no evidence of significant positive associations between breast cancer risk and cigarette smoking, alcohol consumption, or OC use in any subgroup of these women. CONCLUSIONS: Our results support the hypothesis that excess adipose deposition heightens breast cancer risk in the postmenopausal years. Furthermore, they underscore the need for continuing investigation of the effects of exogenous estrogens on the development of this malignancy, particularly in lean postmenopausal women.

Comparative epidemiology of cancer between the United States and Italy.

Available statistics on smoking, alcohol, food supply, reproductive history, and other lifestyle habits from the U.S. and Italy were compared and related to mortality rates of common neoplasms over the period 1955 to 1980. Per capita cigarette consumption has declined in the U.S. since the early 1960s but continues to rise in Italy, chiefly due to the recent increase in cigarette smoking among Italian women. Alcohol consumption has increased in both countries, being persistently about 40% higher in Italy. Changes were relatively limited in the American diet, but substantial for the Italian one which had particularly marked increases in meat, milk, and fat consumption. Fertility rates have declined in both countries but more sharply in the U.S. These lifestyle changes were reflected by distinctly divergent trends in cancer mortality rates between the two countries. In Italian males, mortality rates of urinary bladder cancer and alcohol-related neoplasms of the aerodigestive tract (oral cavity, larynx, and esophagus) increased in a similar manner and were persistently elevated relative to American males. Similarly, Italian lung cancer rates, while starting from lower values, rose steadily to overtake American rates in the younger and middle age groups of both sexes, and neoplasms of the intestines, breast, and ovary, starting from considerably lower values, tended to approach the American rates over the 25-year period considered. Within Italy, mortality rates of most common neoplasms were substantially elevated in the North of the country relative to the South, thereby paralleling the distinct North to South gradient in socioeconomics, diet, and affluent lifestyle which exists in the country. In our opinion, most of these trends are real, and their explanation should be sought, partly or largely, in the changes in tobacco and alcohol use, and the reproductive and dietary patterns described. The evidence presented underlies the importance of this kind of exercise to formulate and test etiological hypotheses of human diseases, which may be overlooked in studies based on populations with more homogeneous lifestyle habits or environmental exposures.

Chemoprevention of breast cancer in rats by celecoxib, a cyclooxygenase 2 inhibitor.

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been observed to reduce the relative risk of breast cancer. This prompted our investigation of the chemopreventive potential of celecoxib, a specific cyclooxygenase 2 blocker, against mammary carcinogenesis induced by 7,12-dimethyl-benz(a)anthracene in female Sprague Dawley rats. Treatment with celecoxib was examined and compared to treatment with the general NSAID, ibuprofen, and to a control group receiving only dimethylbenz(a)anthracene. Dietary administration of celecoxib (1500 ppm) produced striking reductions in the incidence, multiplicity, and volume of breast tumors relative to the control group (68%, 86%, and 81%, respectively; P < 0.001). Ibuprofen also produced significant effects, but of lesser magnitude (40%, 52%, and 57%, respectively; P < 0.001). These results help confirm the chemopreventive activity of NSAIDs against breast cancer and provide the first evidence that a cyclooxygenase 2 blocking agent, celecoxib, possesses strong chemopreventive activity against mammary carcinogenesis.

Altered fMRI resting-state connectivity in individuals with fibromyalgia on acute pain stimulation.

BACKGROUND: Fibromyalgia is a chronic widespread pain condition, with patients commonly reporting other symptoms such as sleep difficulties, memory complaints and fatigue. The use of magnetic resonance imaging (MRI) in fibromyalgia has allowed for the detection of neural abnormalities, with alterations in brain activation elicited by experimental pain and alterations in resting state connectivity related to clinical pain. METHODS: In this study, we sought to monitor state changes in resting brain connectivity following experimental pressure pain in fibromyalgia patients and healthy controls. Twelve fibromyalgia patients and 15 healthy controls were studied by applying discrete pressure stimuli to the thumbnail bed during MRI. Resting-state functional MRI scanning was performed before and immediately following experimental pressure pain. We investigated changes in functional connectivity to the thalamus and the insular cortex. RESULTS: Acute pressure pain increased insula connectivity to the anterior cingulate and the hippocampus. Additionally, we observed increased thalamic connectivity to the precuneus/posterior cingulate cortex, a known part of the default mode network, in patients but not in controls. This connectivity was correlated with changes in clinical pain. CONCLUSIONS: These data reporting changes in resting-state brain activity following a noxious stimulus suggest that the acute painful stimuli may contribute to the alteration of the neural signature of chronic pain. WHAT DOES THIS STUDY/ADD?: In this study acute pain application shows an echo in functional connectivity and clinical pain changes in chronic pain.

Escalating dose of continuous infusion combination chemotherapy for refractory neuroblastoma.

PURPOSE: This trial was undertaken to determine if a continuous infusion format with increased dose-intensity had antitumor activity with tolerable toxicity in patients with advanced neuroblastoma. PATIENTS AND METHODS: Forty heavily pretreated patients with refractory or progressive neuroblastoma received continuous infusion doxorubicin, cisplatin, and etoposide along with bolus ifosfamide in a dose-escalation format. A total of 79 courses of chemotherapy were administered at five different dose levels. RESULTS: Fifteen of 35 assessable patients (43%) achieved either a partial response (PR) or complete response (CR), including five patients with a CR, three with a very good PR (VGPR), and seven with a PR. Hematologic toxicity was severe, but reversible, and other toxicities, although significant, were tolerable and much less than that accepted in a bone marrow transplantation (BMT) setting. CONCLUSION: This investigation illustrates that response is possible even in an extremely poor-prognosis group of patients, and it suggests that such a regimen may be effective if given before disease progression occurs.

Double-alkylator non-total-body irradiation regimen with autologous hematopoietic stem-cell transplantation in pediatric solid tumors.

PURPOSE: To determine the maximum-tolerated dose (MTD) of cyclophosphamide (CTX) when administered with fixed doses of carboplatin, etoposide, and melphalan (CEM) followed by autologous hematopoietic stem-cell transplantation (HSCT) in children with recurrent or high-risk solid tumors as a consolidation chemotherapy, and to make preliminary observations on efficacy. PATIENTS AND METHODS: Twenty-seven patients with solid tumors between the ages of 2 and 21 years were enrolled. Twenty of 27 had recurrent disease, whereas seven were treated in first remission. Nine were treated with melphalan 50 mg/m2/d for 4 days, carboplatin 300 mg/m2/d for 4 days as a continuous infusion (CI), and etoposide 200 mg/m2/d for 4 days as a CI (level I). CTX 750 mg/m2/d for 4 days was added to this regimen for the next 18 patients (level II). Seven of nine patients at level I and four of 18 at level II received bone marrow (BM) only, while two of nine at level I and 14 of 18 at level II received BM plus peripheral-blood stem cells (PBSC). RESULTS: The median time to reach an absolute neutrophil count (ANC) greater than 500/microl was 12.5 and 10 days for patients who received BM only and BM plus PBSC, respectively. Three cases of grade 3 mucositis, one Candida sepsis, and two transient hypoxemias were the main nonfatal toxicities. No toxic mortality was observed among level I patients. Three of 18 (16%) level II patients, all in second CR, died of transplant-related complications. Median follow-up is 29 months. Nine died of progressive disease (one second malignancy), six relapsed and are alive with disease, and nine are in continuous CR. Among the 15 PNET/Ewing's sarcoma patients, seven are in continuous CR (three of nine in second CR/VGPR, four of six in first CR/VGPR). CONCLUSION: The addition of CTX 3 g/m2 to CEM followed by autologous HSCT as a consolidation therapy resulted in 16% toxic mortality in children with recurrent or high-risk solid tumors. Further CTX dose escalation was aborted. No common nonhematologic toxicity was identified. The event-free survival (EFS) of 66% +/- 19% at 3 years for patients with metastatic PNET/Ewing's sarcoma in first remission is encouraging. However, this is based on only six patients. Both level I and II need further exploration in high-risk pediatric solid tumors in first remission.

Allogeneic versus autologous purged bone marrow transplantation for neuroblastoma: a report from the Childrens Cancer Group.

PURPOSE: We have compared the toxicity, relapse rate, and progression-free survival (PFS) of high-risk neuroblastoma patients receiving identical induction therapy and myeloablative chemotherapy plus total-body irradiation (TBI) followed by allogeneic or autologous purged bone marrow transplantation (BMT). PATIENTS AND METHODS: Fifty-six patients with high-risk neuroblastoma underwent BMT at investigator and parent option if they did not have progressive disease after induction chemotherapy with cisplatin, cyclophosphamide, doxorubicin, and etoposide. After surgery and local radiation to residual tumor, myeloablative therapy consisting of etoposide, melphalan, cisplatin, and TBI was given followed by BMT. Patients with human leukocyte antigen (HLA)-compatible siblings received allogeneic bone marrow (n = 20). The remaining patients (n = 36) received autologous bone marrow that had undergone multimodality purging and had no remaining detectable tumor cells by immunocytology. RESULTS: Four of 20 allogeneic patients had a treatment-related death, compared with three of 36 autologous patients (P = .21). The relapse rate among allogeneic BMT patients was 69%, compared with 46% for autologous BMT patients (P = .14). The estimated PFS rates 4 years after BMT were 25% for allogeneic BMT patients and 49% for autologous BMT patients (P = .051). CONCLUSION: Overall outcome for patients with neuroblastoma given this same induction therapy followed by autologous purged marrow was similar to that with allogeneic marrow, although bias in patients selection cannot be excluded in a nonrandomized comparison.

Pilot study of high-dose thiotepa and etoposide with autologous bone marrow rescue in children and young adults with recurrent CNS tumors. The Children's Cancer Group.

PURPOSE: This study was designed to determine the toxicity, radiographic response rate, and outcome following high-dose thiotepa, etoposide, and autologous bone marrow rescue (ABMR) for young patients with recurrent malignant brain tumors. METHODS: Eligibility criteria required adequate renal, hepatic, and pulmonary function, and no bone marrow infiltration. Thiotepa 300 mg/m2 and etoposide 500 mg/ m2 were infused on 3 consecutive days, and autologous bone marrow was infused 72 hours following chemotherapy. RESULTS: Forty-five patients with recurrent high-grade brain tumors, aged 8 months to 36 years (median, 8 years), were treated. Seven patients (16%) died of treatment-related toxicities within 56 days of marrow reinfusion. Delayed platelet engraftment occurred in 44% of patients who survived beyond day 56. Of 35 patients with radiographically measurable disease who survived at least 28 days following ABMR, there were two complete responses (CRs) and six partial responses (PRs), for an overall response (CRs plus PRs) rate of 23% (SE = 7%). Objective responses were observed in four of 14 assessable patients with high-grade glioma and in two of six with primitive neuroectodermal tumors (PNETs)/ medulloblastoma. Survival was significantly improved in patients treated with minimal residual disease (P < .0005). Five of 18 patients (28%) with high-grade gliomas remain free of disease at 39+, 44+, 49+, 52+, and 59+ months post-ABMR. CONCLUSION: The combination of high-dose thiotepa and etoposide has activity against a variety of recurrent childhood brain tumors. These results merit further evaluation in children and young adults with both recurrent and newly diagnosed high-grade brain tumors.

Long-term follow-up of short intensive multiagent chemotherapy without high-dose methotrexate ('Orange') in children with advanced non-lymphoblastic non-Hodgkin's lymphoma: a children's cancer group report.

Despite prolonged therapy (18 months), children with advanced non-lymphoblastic, non-Hodgkin's lymphoma (NHL) treated on previous Children's Cancer Group (CCG) trials achieved less than a 60% 5-year event-free survival (EFS). In this study we piloted a shorter but more intensive protocol ('Orange') to determine the feasibility, safety, and efficacy of this alternative treatment approach. Thirty-nine children received a CHOP-based induction, etoposide/ifosfamide consolidation, DECAL (dexamethasone, etoposide, cisplatin, cytosine arabinoside (Ara-C) and L-asparaginase) intensification, and either one or two similar but less intense maintenance courses. Patients were stratified to standard-risk (5 months) vs high-risk (7 months) treatment. High risk was defined as either bone marrow disease, CNS disease, mediastinal mass > or = one-third thoracic diameter at T5 and/or LDH > or =2 times institutional upper limits of normal. All other patients were considered to be standard risk. Results were compared with the previous CCG NHL study (CCG-503). Sixteen and 23 patients were considered standard- vs. high-risk, respectively. The 5-year EFS and overall survival (OS) were 77 +/- 7% and 80 +/- 7%, respectively. The 5-year EFS and OS were significantly better in the standard- vs. high-risk subgroups (100% vs. 61 +/- 11%) (P < 0.003) and (100% vs. 65 +/- 11%) (P < 0.01), respectively. Lactate dehydrogenase (LDH) > or =2 x normal (NL) was associated with significantly poorer outcomes (LDH > or =2 x NL vs. <2 x NL) (5-year EFS: 55 +/- 12% vs. 100%) (P < 0.0004). This CCG hybrid regimen, 'Orange', of short and more intensive therapy resulted in a significant improvement in outcomes compared with the previous CCG trial of more prolonged but less intense therapy. This regimen that deletes high-dose methotrexate, if confirmed in a larger trial, could be considered as an alternative treatment approach in children without high tumor burdens (LDH <2 x NL) and Murphy stage III disease.

The effect of graft purging with 4-hydroperoxycyclophosphamide in autologous bone marrow transplantation for acute myelogenous leukemia.

BACKGROUND: Autologous bone marrow transplantation is an important therapy for patients with acute myelogenous leukemia (AML). However, leukemia in the graft may contribute to posttransplant relapse. Treatment of the graft with 4-hydroperoxycyclophosphamide (4HC) is sometimes used to decrease numbers of infused leukemia cells (4HC purging). No large controlled trials evaluating efficacy and toxicity of 4HC purging are reported. METHODS: We studied 294 patients reported to the Autologous Blood and Marrow Registry receiving either a 4HC-purged (n = 211) or unpurged (n = 83) autograft for AML in first (n = 209) or second (n = 85) remission. Analyses were restricted to patients transplanted less than 6 months after achieving remission. Using Cox proportional hazards regression, we compared time to treatment failure (death or relapse, inverse of leukemia-free survival) after 4HC-purged vs unpurged transplants while controlling for important prognostic factors. RESULTS: Median duration of posttransplant neutropenia was 40 (range, 10-200) days after 4HC-purged transplants and 29 (9-97) days after unpurged transplants (p < 0.01). Transplant-related mortality was similar in the two groups. In multivariate analysis, patients receiving 4HC-purged transplants had lower risks of treatment failure than those receiving unpurged transplants (relative risk, 0.69, p = 0.12 in the first posttransplant year; relative risk, 0.28, p < 0.0001 thereafter). Adjusted three-year probabilities of leukemia-free survival (95% confidence interval) were 56% (47-64%) and 31% (18-45%) after 4HC-purged and unpurged transplants in first remission, respectively. Corresponding probabilities in second remission were 39% (25-53%) and 10% (1-29%). CONCLUSION: Grafts purged with 4HC are associated with higher leukemia-free survival after autologous bone marrow transplants for AML.

Grasshopper, a long terminal repeat (LTR) retroelement in the phytopathogenic fungus Magnaporthe grisea.

The fungal phytopathogen Magnaporthe grisea parasitizes a wide variety of gramineous hosts. In the course of investigating the genetic relationship between pathogen genotype and host specificity we identified a retroelement that is present in some strains of M. grisea that infect finger millet and goosegrass (members of the plant genus Eleusine). The element, designated grasshopper (grh), is present in multiple copies and dispersed throughout the genome. DNA sequence analysis showed that grasshopper contains 198 base pair direct, long terminal repeats (LTRs) with features characteristic of retroviral and retrotransposon LTRs. Within the element we identified an open reading frame with sequences homologous to the reverse transcriptase, RNaseH, and integrase domains of retroelement pol genes. Comparison of the open reading frame with sequences from other retroelements showed that grh is related to the gypsy family of retrotransposons. Comparisons of the distribution of the grasshopper element with other dispersed repeated DNA sequences in M. grisea indicated that grasshopper was present in a broadly dispersed subgroup of Eleusine pathogens, suggesting that the element was acquired subsequent to the evolution of this host-specific form. We present arguments that the amplification of different retroelements within populations of M. grisea is a consequence of the clonal organization of the fungal populations.

Longevity in obese and lean male and female rats of the Zucker strain: prevention of hyperphagia.

Zucker obese (fa/fa) and lean (Fa/Fa) rats were fed a soy protein diet ad libitum under barrier conditions from 4 wk of age until death. Obese rats were also pair fed with lean controls to prevent hyperphagia. Time of death was determined and tissues collected at necropsy for histologic examination. Lean rats had longer 10th percentile survivorship (males 966 compared with 667 d, females 983 compared with 620 d) and maximum life spans (males 1067 compared with 803 d, females 1163 compared with 744 d) than did obese rats. Preventing hyperphagia increased maximum life span in both males (1010 d) and females (975 d). Pathologies in lean rats were similar to those reported for other rodent strains. For obese rats fed ad libitum, end-stage renal disease (ESRD) was the major cause of mortality (males: 91.1%, females: 93.3%). Prevention of hyperphagia decreased deaths attributable to ESRD (males: 64.4%, females: 51.1%). A smaller restriction in energy intake (8-18%) required to prevent hyperphagia compared with the 35-40% in most other studies produced similar increases in longevity, suggesting that obese Zucker rats are particularly sensitive to energy restriction. Amelioration of early onset of renal disease is a likely explanation. Percentage body fat in food-restricted obese rats did not differ from that of animals fed ad libitum; thus, reduced longevity is not the result of obesity per se, but rather is influenced by other metabolic pathologies occurring in this strain of rats homozygous for the fa gene. Because microalbuminuria with progression to ESRD is a complication in human obesity, the Zucker strain offers the opportunity to investigate initiating mechanisms of this pathology.

Metabolites of a tobacco-specific nitrosamine, 4-(methylnitrosamino)- 1-(3-pyridyl)-1-butanone (NNK), in the urine of smokeless tobacco users: relationship between urinary biomarkers and oral leukoplakia.

Two metabolites of the carcinogenic tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone were quantified in the urine of smokeless tobacco users. The metabolites are 4-(methylnitrosamino) -1-(3-pyridyl)-1-butanol (NNAL) and [4-(methylnitrosamino)-1-(3-pyridyl) but-1-yl]-beta-O-D-glucosiduronic acid (NNAL-Gluc). The study population consisted of 47 male nonsmokers, of whom 23 were snuff dippers, 13 were tobacco chewers, 3 were users of both products, and 8 were nonusers. The levels of NNAL-Gluc in urine ranged from 0.14-30.3 pmol/mg creatinine with a mean +/- SD of 3.47 +/- 5.86, whereas the levels of NNAL ranged from 0.02-8.73 pmol/mg creatinine with a mean +/- SD of 0.92 +/- 1.59. The mean levels of NNAL-Gluc and NNAL were not significantly different from those measured in a previous study of smokers. The levels of NNAL-Gluc were significantly higher in snuff dippers than in tobacco chewers. The ratio of NNAL-Gluc:NNAL was higher in snuff dippers than in tobacco chewers or smokers. There was no indication of two phenotypes of the NNAL-Gluc:NNAL ratio in smokeless tobacco users, in contrast to previous observations in smokers. Of the 39 smokeless tobacco users in this study, 16 presented with oral leukoplakia. When the total levels of NNAL-Gluc, NNAL, or NNAL-Gluc + NNAL were divided into tertiles, there was a significant association between the presence of leukoplakia and increasing levels of these metabolites; a similar relationship was found between urinary cotinine and leukoplakia. The results of this study demonstrate that there is significant uptake of carcinogenic nitrosamines in smokeless tobacco users, and that such products are not harmless alternatives to cigarettes. Moreover, the urinary biomarkers NNAL-Gluc, NNAL, and cotinine were associated with the presence of leukoplakia, which provides biochemical support for the role of smokeless tobacco products as a cause of oral leukoplakia.

Immunosuppressive therapy versus bone marrow transplantation for children with aplastic anemia.

A total of 15 patients 1 to 16 years of age were treated for aplastic anemia (13 of a severe degree) and followed-up for a mean of 24 months (range 2 to 64 months). Six patients had an HLA-matched sibling and underwent allogeneic bone marrow transplantation. Nine patients who lacked a suitable donor were given immunosuppressive therapy. Antithymocyte globulin was the initial treatment for eight of these nine patients. Two patients who failed to respond to antithymocyte globulin were then treated with cyclosporine A. Pretreatment age, hematologic measurements, duration of follow-up, and interval prior to therapy were similar between the two groups. All of the patients receiving bone marrow transplants had a complete response and now have normal blood cell counts. Six of nine patients (67%) responded to antithymocyte globulin and are now transfusion free, although three have mild thrombocytopenia. Both patients given cyclosporine A had a good response and are also transfusion free. Patients who underwent marrow transplantation had a significantly shorter period of transfusion dependence for RBCs (9 v 4 weeks, P less than .005) and platelets (5 v 21 weeks, P less than .05). The patients given immunosuppressive therapy have significantly lesser platelet counts in follow-up but have similar values for both hemoglobin and absolute granulocyte counts. Although HLA-matched bone marrow transplantation leads to a faster and more complete recovery for children with aplastic anemia, immunosuppressive therapy can provide a good outcome for children with this disorder.

Ibuprofen-induced inhibition of cyclooxygenase isoform gene expression and regression of rat mammary carcinomas.

A single dose of 75 mg/kg 7,12 dimethylbenz[a]anthracene was administered to 50-day-old virgin female Sprague-Dawley rats and 100 days later, animals were randomized and provided with Teklad rodent chow mixed with a dose of 25 mg/rat/day ibuprofen for 35 days. Ibuprofen treatment reduced tumor volume (P < 0.05) and significantly inhibited gene expression of both cyclooxygenase- and cyclooxygenase-2 (P < 0.02). These results indicate that ibuprofen induced significant regression of established mammary carcinomas which was associated with inhibition of expression of isoforms of the gene responsible for prostaglandin production.