Medication use and the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis

BACKGROUND

Toxic epidermal necrolysis and Stevens-Johnson syndrome are rare, life-threatening, drug-induced cutaneous reactions. We conducted a case-control study to quantify the risks associated with the use of specific drugs.

METHODS

Data were obtained through surveillance networks in France, Germany, Italy, and Portugal. Drug use before the onset of disease was compared in 245 people who were hospitalized because of toxic epidermal necrolysis or Stevens-Johnson syndrome and 1147 patients hospitalized for other reasons (controls). Crude relative risks were calculated and adjusted for confounding by multivariate methods when numbers were large enough.

RESULTS

Among drugs usually used for short periods, the risks were increased for trimethoprim-sulfamethoxazole and other sulfonamide antibiotics (crude relative risk, 172; 95 percent confidence interval, 75 to 396), chlormezanone (crude relative risk, 62; 21 to 188), aminopenicillins (multivariate relative risk, 6.7; 2.5 to 18), quinolones (multivariate relative risk, 10; 2.6 to 38), and cephalosporins (multivariate relative risk, 14; 3.2 to 59). For acetaminophen, the multivariate relative risk was 0.6 (95 percent confidence interval, 0.2 to 1.3) in France but 9.3 (3.9 to 22) in the other countries. Among drugs usually used for months or years, the increased risk was confined largely to the first two months of treatment, when crude relative risks were as follows: carbamazepine, 90 (95 percent confidence interval, 19 to infinity); phenobarbital, 45 (19 to 108); phenytoin, 53 (11 to infinity); valproic acid, 25 (4.3 to infinity); oxicam nonsteroidal antiinflammatory drugs (NSAIDs), 72 (25 to 209); allopurinol, 52 (16 to 167); and corticosteroids, 54 (23 to 124). For many drugs, including thiazide diuretics and oral hypoglycemic agents, there was no significant increase in risk.

CONCLUSIONS

The use of antibacterial sulfonamides, anticonvulsant agents, oxicam NSAIDs, allopurinol, chlormezanone, and corticosteroids is associated with large increases in the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis. But for none of the drugs does the excess risk exceed five cases per million users per week.

Axonal swellings and degeneration in mice lacking the major proteolipid of myelin

Glial cells produce myelin and contribute to axonal morphology in the nervous system. Two myelin membrane proteolipids, PLP and DM20, were shown to be essential for the integrity of myelinated axons. In the absence of PLP-DM20, mice assembled compact myelin sheaths but subsequently developed widespread axonal swellings and degeneration, associated predominantly with small-caliber nerve fibers. Similar swellings were absent in dysmyelinated shiverer mice, which lack myelin basic protein (MBP), but recurred in MBP*PLP double mutants. Thus, fiber degeneration, which was probably secondary to impaired axonal transport, could indicate that myelinated axons require local oligodendroglial support.

Human lymphocytes bearing T cell receptor gamma/delta are phenotypically diverse and evenly distributed throughout the lymphoid system

A direct quantitative and phenotypic cytofluorographic analysis of TCR-gamma/delta+ lymphocytes as well as an immunohistologic study of their tissue distribution and microanatomy was made possible by the availability of two mAbs (anti-TCR-delta 1 and anti-C gamma M1) specific for framework determinants on human TCR gamma and delta chains, respectively. TCR-gamma/delta+ lymphocytes, ranging between greater than 0.5 and 16% of CD3+ cells, were found in fetal and postnatal thymus, fetal and adult peripheral lymphoid organs, and adult peripheral blood. While TCR-gamma/delta+ lymphocytes comprised a small subpopulation of T cells (mean, approximately 4%) occasionally greater than 10-16% of CD3+ cells expressed TCR-gamma/delta. Virtually all TCR-gamma/delta+ thymocytes/lymphocytes expressed CD7, CD2, and CD5 but were heterogeneous with respect to their expression of CD1, CD4, CD8, CD28, CD11b, CD16, and Leu-7. Human TCR-gamma/delta+ cells populate both organized lymphoid tissues (thymus, tonsil, lymphnode, and spleen) as well as the gut- and skin-associated lymphoid systems at similar frequencies without obvious tropism for epithelial microenvironments. TCR-gamma/delta+ lymphocytes tend to be located within a given organ wherever TCR-alpha/beta+ lymphocytes are found. This study shows that TCR-gamma/delta+ lymphocytes constitute a small but numerically important, phenotypically diverse T cell population distributed throughout the body. These results support the concept that TCR-gamma/delta+ cells comprise a distinct, functionally heterogeneous, mature T cell sublineage that may substantially broaden the T cell repertoire at all immunologically relevant sites.

UV exposure reduces immunization rates and promotes tolerance to epicutaneous antigens in humans: relationship to dose, CD1a-DR+ epidermal macrophage induction, and Langerhans cell depletion

Increasing UVB radiation at the earth's surface might have adverse effects on in vivo immunologic responses in humans. We prospectively randomized subjects to test whether epicutaneous immunization is altered by prior administration of biologically equalized doses of UV radiation. Multiple doses of antigens on upper inner arm skin (UV protected) were used to elicit contact sensitivity responses, which were quantitated by measuring increases in skin thickness. If a dose of UVB sufficient to induce redness (erythemagenic) was administered to the immunization site prior to sensitization with dinitrochlorobenzene (DNCB), we noted a marked reduction in the degree of sensitization (P less than 0.0006) that was highly dose responsive (r = 0.98). Even suberythemagenic UV (less than a visible sunburn) resulted in a decreased frequency of strongly positive responses (32%) as compared to controls (73%) (P = 0.019). The rate of immunologic tolerance to DNCB (active suppression of a subsequent repeat immunization) in the groups that were initially sensitized on skin receiving erythemagenic doses of UV was 31% (P = 0.0003). In addition, a localized moderate sunburn appeared to modulate immunization with diphenylcyclopropenone through a distant, unirradiated site (41% weak responses) as compared to the control group (9%) (P = 0.05). Monitoring antigen presenting cell content in the epidermis revealed that erythemagenic regimens induced CD1a-DR+ macrophages and depleted Langerhans cells. In conclusion, relevant and even subclinical levels of UV exposure have significant down modulatory effects on the ability of humans to generate a T-cell-mediated response to antigens introduced through irradiated skin.

Administration of recombinant IL-12 to normal mice enhances cytolytic lymphocyte activity and induces production of IFN-gamma in vivo

IL-12 is a heterodimeric cytokine that has been shown to enhance natural killer (NK) and cytotoxic T lymphocyte (CTL) responses, and to induce IFN-gamma production in vitro. In this study, we have examined the effects in vivo of administering purified murine rIL-12 to normal mice. Daily injections of rIL-12 i.p. (1 ng to 10 micrograms/day) caused dose-dependent enhancement of NK cell lytic activity in the spleens and livers of treated mice. Histologic examination of the livers of IL-12-treated mice revealed focal mononuclear cell infiltrates, and flow cytometry studies indicated that the livers of IL-12-treated mice contained increased numbers of NK cells, CD8+ T cells, and monocytes. Liver and splenic lymphoid cells from IL-12-treated mice, unlike liver and splenic lymphoid cells from control mice, spontaneously secreted IFN-gamma in vitro, suggesting that they had been induced by IL-12 to produce IFN-gamma in vivo. Consistent with this, IFN-gamma could be detected in the serum of IL-12-treated mice. In mice which had been immunized by footpad injection of allogeneic splenocytes, daily administration of rIL-12 i.p. was shown to enhance the specific CTL response in the draining lymph nodes. Thus, these studies demonstrate that IL-12 can enhance NK and CTL activity and induce IFN-gamma production in vivo, as well as in vitro, and suggest possible mechanisms by which IL-12 may exert therapeutic effects in the treatment of some tumors and infectious diseases.

The B lymphocyte adhesion molecule CD22 interacts with leukocyte common antigen CD45RO on T cells and alpha 2-6 sialyltransferase, CD75, on B cells

Functional maturation of B lymphocytes correlates with expression of the B lineage-specific cell surface glycoprotein CD22. Two CD22 polypeptides have been characterized and suggested to play a role in B cell-B cell interaction as well as in B cell adhesion to monocytes. In this work we provide evidence that CD22 is directly involved in the cognate interaction between B and T cells. One of the two CD22 polypeptides, CD22 beta, interacts with a specific ligand on a subpopulation of CD4+ T cells. Our results suggest that the T cell ligand of CD22 is CD45RO, an isoform of the leukocyte common antigen class of phosphotyrosine phosphatases associated with the helper T cell phenotype. We further demonstrate that CD22 recognizes a second ligand, CD75, expressed predominantly on activated B cells and shown to be a cell surface alpha 2-6 sialyltransferase.

Hypomagnesemia and renal magnesium wasting in patients receiving cisplatin

We studied renal function and serum electrolytes in 51 patients receiving cisplatin chemotherapy by retrospectively reviewing the charts of 44 patients and prospectively following seven patients. Hypomagnesemia developed in 23 of 44 evaluable patients who were receiving cisplatin. We documented inappropriate renal magnesium wasting in four patients. Two patients required hospitalization for symptomatic hypomagnesemia. We conclude that cisplatin can induce a renal tubular defect in magnesium conservation and serious clinical syndromes of magnesium deficiency.

Infusion of alpha-galactosidase A reduces tissue globotriaosylceramide storage in patients with Fabry disease

Fabry disease is a lysosomal storage disorder caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). This enzymatic defect results in the accumulation of the glycosphingolipid globotriaosylceramide (Gb(3); also referred to as ceramidetrihexoside) throughout the body. To investigate the effects of purified alpha-gal A, 10 patients with Fabry disease received a single i.v. infusion of one of five escalating dose levels of the enzyme. The objectives of this study were: (i) to evaluate the safety of administered alpha-gal A, (ii) to assess the pharmacokinetics of i.v.-administered alpha-gal A in plasma and liver, and (iii) to determine the effect of this replacement enzyme on hepatic, urine sediment and plasma concentrations of Gb(3). alpha-Gal A infusions were well tolerated in all patients. Immunohistochemical staining of liver tissue approximately 2 days after enzyme infusion identified alpha-gal A in several cell types, including sinusoidal endothelial cells, Kupffer cells, and hepatocytes, suggesting diffuse uptake via the mannose 6-phosphate receptor. The tissue half-life in the liver was greater than 24 hr. After the single dose of alpha-gal A, nine of the 10 patients had significantly reduced Gb(3) levels both in the liver and shed renal tubular epithelial cells in the urine sediment. These data demonstrate that single infusions of alpha-gal A prepared from transfected human fibroblasts are both safe and biochemically active in patients with Fabry disease. The degree of substrate reduction seen in the study is potentially clinically significant in view of the fact that Gb(3) burden in Fabry patients increases gradually over decades. Taken together, these results suggest that enzyme replacement is likely to be an effective therapy for patients with this metabolic disorder.

Phase II study of taxol, merbarone, and piroxantrone in stage IV non-small-cell lung cancer: The Eastern Cooperative Oncology Group Results

BACKGROUND

Patients with metastatic (stage IV) non-small-cell lung cancer usually have a poor prognosis and disease refractory to chemotherapy. Three new agents--taxol, merbarone, and piroxantrone--have shown promising antitumor treatment in vitro and in animals. Taxol is an antimicrotubular agent that interferes with mitosis during cell division. Merbarone, a conjugate of thiobarbituric acid and aniline, is a topoisomerase II inhibitor, which thus inhibits DNA synthesis and tumor growth. Piroxantrone, an anthracenedione derivative, is a DNA intercalating agent that has shown potent antitumor activity in animal studies.

PURPOSE

Our randomized phase II study was designed to evaluate the efficacy and toxicity of these agents in the treatment of stage IV metastatic non-small-cell lung cancer.

METHODS

Eligible patients (119) were randomly assigned to receive one of the three treatments given every 3 weeks: 250 mg/m2 taxol by a 24-hour intravenous infusion, 1000 mg/m2 merbarone by continuous intravenous infusion through a central catheter daily for 5 days, or 150 mg/m2 piroxantrone by intravenous infusion over 1 hour. Patients had received no chemotherapy. Response and toxicity were evaluated every 3 weeks.

RESULTS

Twenty-five patients were randomly assigned to receive taxol, 47 to receive merbarone, and 47 to receive piroxantrone. One of 44 assessable patients (2.3%) treated with piroxantrone had a complete response. Rates for partial response were 20.8% (five of 24 patients) and 5.7% (two of 35) for assessable patients treated with taxol or merbarone, respectively. One-year survival rates were 41.7%, 21.6%, and 22.6%, and median survival times were 24.1, 19.9, and 29.3 weeks for taxol, merbarone, and piroxantrone, respectively. These differences were not statistically significant, but this study was not designed to compare survival. In general, toxicity was manageable. With premedication, no anaphylaxis was observed with taxol. The most common toxic effects were leukopenia with taxol or piroxantrone treatment and thromboembolic complications with merbarone. Death directly related to treatment occurred in 4% (one patient), 11.4% (four), and 5% (two) of the assessable patients receiving taxol, merbarone, and piroxantrone, respectively. Cardiotoxicity and neurotoxicity occurred only occasionally in all three arms.

CONCLUSION

On the basis of the response rate (20.8% partial response) and 1-year survival rate (41.7%), taxol is an active agent for the treatment of metastatic non-small-cell lung cancer. Merbarone and piroxantrone are relatively inactive.

IMPLICATIONS

Further study of taxol is warranted. In future studies, taxol should be combined with other agents, and granulocyte colony-stimulating factor should be used to ameliorate myelosuppression.

Advanced ovarian adenocarcinoma. A prospective clinical trial of melphalan (L-PAM) versus combination chemotherapy

Eighty patients with advanced ovarian adenocarcinoma were treated in a prospective, randomized trial comparing a four-drug combination--hexamethylmelamine, cyclophosphamide, methotrexate and 5-fluorouracil--with the oral alkylating agent, melphalan. Treatment with the four-drug combination was associated with a significantly increased overall response rate (75 vs. 54 per cent) (P less than 0.05), more complete remissions (33 vs. 16 per cent) and longer median survival (29 vs. 17 months) (P less than 0.02) but more severe toxicity than occurred with melphalan. Patients with minimal residual disease had a significantly higher overall response rate than patients with extensive residual disease (84 vs. 53 per cent) (P less than 0.05). Patients with advanced disease who achieved a complete remission documented by peritoneoscopy or laparotomy (or both) have a median survival that will exceed three years. The four-drug regimen is more effective than melphalan in the management of advanced ovarian adenocarcinoma.

Exercise echocardiography is an accurate and cost-efficient technique for detection of coronary artery disease in women

OBJECTIVES

This study compared the accuracy and cost implications of using exercise echocardiography and exercise electrocardiography for detection of coronary artery disease in women.

BACKGROUND

The specificity of exercise electrocardiography in women is lower than in men. Exercise echocardiography accurately identifies coronary artery disease in women, but its utility in place of exercise electrocardiography is unclear.

METHODS

One hundred sixty-one women without a previous Q wave infarction underwent exercise echocardiography and coronary angiography. Positive findings were a new or worsening wall motion abnormality on the exercise echocardiogram and ST segment depression > 0.1 mV at 0.08 s after the J point on the exercise electrocardiogram (ECG).

RESULTS

Coronary artery stenosis > 50% diameter narrowing was present in 59 patients; the sensitivity (mean +/- SD) of exercise echocardiography was 80 +/- 3%. In 48 patients with an interpretable ECG, the sensitivity of exercise echocardiography was 81 +/- 4%, and that of the exercise ECG was 77 +/- 3% (p = 0.50). In 102 patients without coronary artery disease, the overall specificity of exercise echocardiography was 81 +/- 4%. In 70 patients with an interpretable ECG, the specificity of exercise echocardiography (80 +/- 3%) exceeded that of the exercise ECG (56 +/- 4%, p < 0.0004). The accuracy of exercise echocardiography was also greater than exercise electrocardiography (81 +/- 5% vs. 64 +/- 6%, p < 0.005). Exercise echocardiography stratified significantly more patients of intermediate (20% to 80%) pretest disease probability into the high (> 80%) or low (< 20%) posttest probability group. In women without a previous exercise ECG, the specificity of exercise echocardiography continued to exceed that of exercise electrocardiography (80 +/- 3% vs. 64 +/- 3%, p = 0.05). Exercise echocardiography had the best balance between accuracy and cost for the diagnosis of coronary artery disease in women.

CONCLUSIONS

Exercise echocardiography is more specific than exercise electrocardiography for diagnosis of coronary artery disease in women and is a cost-effective approach to the diagnosis of coronary artery disease because of the avoidance of inappropriate angiography.

The toxicology of interleukin-12: a review

Recombinant murine interleukin (IL)-12 (rmIL-12) exhibits antitumor, antiviral, and antimicrobial activities and can modify allergic inflammatory reactions in animal models. Recombinant human IL-12 (rhIL-12) is currently in clinical trials for treatment of cancer, asthma, and viral hepatitis. Principally a phagocyte-derived cytokine, IL-12 targets natural killer cells and T lymphocytes, stimulating their activity and the secretion of interferon (IFN)-gamma. An understanding of the toxicology of IL-12, due in part to effects mediated by IFN-gamma, has emerged from preclinical safety and mechanistic studies and initial clinical trials. Target organs common to several animal species and humans include the lymphohematopoietic system, intestines, liver, and lung.

Biomechanics and running economy

Running economy, which has traditionally been measured as the oxygen cost of running at a given velocity, has been accepted as the physiological criterion for 'efficient' performance and has been identified as a critical element of overall distance running performance. There is an intuitive link between running mechanics and energy cost of running, but research to date has not established a clear mechanical profile of an economic runner. It appears that through training, individuals are able to integrate and accommodate their own unique combination of dimensions and mechanical characteristics so that they arrive at a running motion which is most economical for them. Information in the literature suggests that biomechanical factors are likely to contribute to better economy in any runner. A variety of anthropometric dimensions could influence biomechanical effectiveness. These include: average or slightly smaller than average height for men and slightly greater than average height for women; high ponderal index and ectomorphic or ectomesomorphic physique; low percentage body fat; leg morphology which distributes mass closer to the hip joint; narrow pelvis and smaller than average feet. Gait patterns, kinematics and the kinetics of running may also be related to running economy. These factors include: stride length which is freely chosen over considerable running time; low vertical oscillation of body centre of mass; more acute knee angle during swing; less range of motion but greater angular velocity of plantar flexion during toe-off; arm motion of smaller amplitude; low peak ground reaction forces; faster rotation of shoulders in the transverse plane; greater angular excursion of the hips and shoulders about the polar axis in the transverse plane; and effective exploitation of stored elastic energy. Other factors which may improve running economy are: lightweight but well-cushioned shoes; more comprehensive training history; and the running surface of intermediate compliance. At the developmental level, this information might be useful in identifying athletes with favourable characteristics for economical distance running. At higher levels of competition, it is likely that 'natural selection' tends to eliminate athletes who failed to either inherit or develop characteristics which favour economy.

Pain and emotion: new research directions

Recently, there has been growing interest in the relation between pain and emotion. Numerous recent studies have been conducted in this area. This article provides an introduction to this interesting area by highlighting selected research topics including studies on: stress and pain, negative emotional states and pain, catastrophizing and pain, the fear of pain, emotional regulation processes and pain, the effects of enhancing emotional regulation on pain, and the relation of emotional distress to treatment seeking in persons having pain. The article concludes with a discussion of important directions for future research in this area.

Orphan nuclear receptor Nurr1 directly transactivates the promoter activity of the tyrosine hydroxylase gene in a cell-specific manner

Tyrosine hydroxylase (TH) catalyzes the first and rate-limiting step of catecholamine synthesis and its expression is necessary for neurotransmitter specification of all catecholaminergic neurons, while dopamine beta-hydroxylase (DBH) is essential for the noradrenergic phenotype. In the present study, we show that Nurr1, an orphan nuclear receptor critical for dopaminergic (DA) neuron development, directly transactivates the promoter activity of the TH gene in a cell type-dependent manner, while it does not regulate the DBH promoter. Consistent with these results, only the TH promoter contains multiple sequence motifs homologous to the known Nurr1-binding motif, NBRE. TH promoter deletional analysis indicates that < 1.0 kb upstream sequences, encompassing three NBRE-like motifs (i.e. NL1, NL2 and NL3) are mostly responsible for the effects of Nurr1. Among these potential motifs, site-directed mutational analysis showed that NL1, residing from - 35 to - 28 bp, was most critical for mediating the transactivation by Nurr1. Strikingly, however, both DNase I footprinting and electrophoretic mobility shift assays showed that NL3, but not NL1 or NL2, has high binding affinity to Nurr1. To determine whether the proximity of these motifs may be important for transactivation by Nurr1 in the transient transfection assay, we generated reporter gene constructs in which NL3 is immediately proximal to the TATA box. Indeed, NL3 was more efficient in this position than NL1 or NL2 for mediating the transactivation by Nurr1. Our results suggest that Nurr1 may play a direct role for specification of DA neurotransmitter identity by activating TH gene transcription in a cell context-dependent manner.

Observation of high-energy astrophysical neutrinos in three years of IceCube data

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8)  GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

Immunohistochemical detection of steroid receptors in breast cancer: a working protocol. UK Receptor Group, UK NEQAS, The Scottish Breast Cancer Pathology Group, and The Receptor and Biomarker Study Group of the EORTC

The biochemical assay for the oestrogen receptor has shown the clinical value of knowing the concentration of the receptor within tissue. The immunohistochemical assay is rapidly taking over from the biochemical assay. Therefore, it is vital to have an equivalent scoring system that will have the same predictive value. This paper reports both a practical protocol and a scoring system that should achieve this aim. This approach should be applicable to many more biomarkers detected by immunohistochemistry.

Central nervous system complications of non-Hodgkin's lymphoma. The potential role for prophylactic therapy

In 38 patients with non-Hodgkin's lymphoma, involvement of the central nervous system (CNS) by malignant lymphoma developed during an eight year period. All patients had lymphomatous meningitis; clinical involvement of the spinal nerves or cranial nerves suggested the diagnosis. Spinal fluid was abnormal in 97 per cent of the patients although a positive cytology could be documented in only 67 per cent by lumbar puncture. The histology in 82 per cent of the patients was diffuse. Involvement of the CNS in nodular lymphoma was uncommon (3 per cent), and the histology in virtually all of these patients had converted to diffuse. At the time of diagnosis of CNS disease, 95 per cent of the patients had other evidence of advanced disease; 66 per cent had bone marrow involvement. In only 18 per cent of the patients did CNS disease develop while they were in clinical remission. Eighty-five per cent of the patients treated with whole brain irradiation and intrathecal chemotherapy had a good clinical response. Knowledge of these risk factors permits definition of a group of patients who may benefit from CNS prophylaxis.

Clinical relevance of the histopathological subclassification of diffuse "histiocytic" lymphoma

Because diffuse "histiocytic" lymphoma, which is an immunologically heterogeneous disease, responds well to chemotherapy in some but not all patients, we attempted to identify the morphologic features that might correlate with its behavior and prognosis. We identified five histopathological categories in 66 patients: one with an excellent prognosis (large, cleaved cell, six of eight patients surviving for two years); two with an intermediate prognosis (large, noncleaved and mixed follicular-center cell, nine of 18 and eight of 17, respectively, surviving for two years); and two with a poor prognosis (blastic and pleomorphic pyroninophilic, one of 10 and two of 13, respectively, surviving for two years). The differences among categories were significant (P less than 0.02) and not dependent on stage (P greater than 0.20). Tumors of follicular-center origin had a better prognosis than tumors of nonfollicular-center origin (P less than 0.01). Differences in survival were due to differences in complete response rate. Morphologic subclassification of diffuse "histiocytic" lymphoma may be useful in predicting response to chemotherapy and survival.

A profile of neuropsychiatric problems and their relationship to quality of life for Parkinson's disease patients without dementia

Neuropsychiatric problems are common in Parkinson's disease (PD) but there is little information regarding how they impact on quality of life. PD patients without dementia (49) were assessed for low mood/depression, fatigue, apathy, sleep problems and hallucinations. Measures of quality of life and motor function were also obtained. Over 77% of the patients reported symptoms consistent with one or more neuropsychiatric problems. Low mood/depression, anxiety and the presence of hallucinations predicted poorer quality of life after controlling for motor symptoms. Additional to the motor symptoms, we found that specific neuropsychiatric problems may impact on quality of life for PD patients.

Evaluation of case reports of aplastic anemia among patients treated with felbamate

PURPOSE

Felbamate (FBM) is a new antiepileptic drug (AED) that is often effective in seizure disorders refractory to other treatments; its use has been greatly restricted after cases of aplastic anemia were reported. To elucidate the putative association between FBM and aplastic anemia, we made a detailed evaluation of the first 31 reports.

METHODS

Hematologic review according to the criteria of the International Agranulocytosis and Aplastic Anemia Study (IAAAS) confirmed 23 cases (74%) as aplastic anemia; FBM was judged to be the only plausible cause for three; confounding (mostly by other drugs) was considered possible, but FBM remained the most likely cause for 11; and there was at least one other plausible cause for 9.

RESULTS

Using a denominator from sales data of 110,000 persons exposed and a numerator of the cases for which FBM was considered the only plausible cause, we established a lower limit of incidence of 27 cases of aplastic anemia per million users as compared with the general population rate of 2.0 per million per year. With all confirmed cases used as the numerator, the upper limit of incidence was 209 per million. The 'most probable" incidence was estimated to be 127 per million.

CONCLUSIONS

Intensive, systematic investigation can maximize the utility of case reports for assessing risks of newly released drugs. The present evaluation confirmed an association between FBM and aplastic anemia; however, confounding was significant for most cases and there was a tenfold range in the "best case" and "worst case" incidence estimates among users.

Current concepts of PLP and its role in the nervous system

Proteolipid protein (PLP) and its smaller isoform DM20 constitute the major myelin proteins of the CNS. Mutations of the X-linked Plp gene cause the heterogeneous syndromes of Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia (SPG) in man and similar dysmyelinating disorders in a range of animal species. A variety of mutations including missense mutations, deletions, and duplications are responsible. Missense mutations cause a predicted alteration in primary structure of the encoded protein(s) and are generally associated with early onset of signs and generalised dysmyelination. The severity of the phenotype varies according to the particular codon involved and the influence of uncharacterised modifying genes. There is some evidence that the dysmyelination results from the altered protein acquiring a novel function deleterious to the oligodendrocyte's function. Transgenic mice carrying extra copies of the Plp gene provide a valid model of PMD/SPG due to gene duplication. Depending on the gene dosage, the phenotype can vary from early onset of severe and lethal dysmyelination through to a very late onset of a tract-specific demyelination and axonal degeneration. Mice with a null mutation of the Plp gene assemble and maintain normal amounts of myelin but develop a progressive axonopathy, again demonstrating tract specificity. The results indicate that the functions of PLP are far from clear. There is good evidence that it is involved in the formation of the intraperiod line of myelin, and the results from the knockout and transgenic mice suggest a role in the interaction of oligodendrocyte and axon.

Generalized anxiety and sleep architecture: a polysomnographic investigation

The sleep of 15 adult subjects who reported heightened generalized anxiety in the absence of other psychiatric syndromes and a 15-adult contrast group were studied by means of nocturnal polysomnography. Analysis of polysomnography variables revealed a significant discriminant function that accounted for 79% of the variance between groups, indicating that high-anxiety/worry subjects took longer to fall asleep, had a smaller percentage of deep (slow-wave) sleep, and more frequent transitions into light sleep [stage 1 nonrapid eye movement (NREM)]. Additional analyses indicated that high-anxiety/worry subjects had a greater percentage of light sleep, more early microarousals, a lower rapid eye movement (REM) density relative to low-anxiety subjects. These subjects also showed more electrodermal storming when slow-wave sleep and REM sleep variables were covaried. Results indicated disrupted sleep depth and continuity similar to that documented in clinical anxiety disorder patients and distinct from that of depressed patients. These results indicate that generalized anxiety and worry in otherwise healthy individuals may act to produce a clinically significant sleep disturbance in the absence of other psychiatric symptoms.