Cutaneous spectrum of coeliac disease

Coeliac disease is characterized by gluten intolerance and immunologically mediated damage to small intestinal mucosa. Patients classically present with gastrointestinal symptoms including chronic diarrhoea, steatorrhoea, weight loss, anorexia and abdominal distension. In a substantial proportion of cases however, gastrointestinal symptoms are minor or absent, and cutaneous manifestations may provide an early clue to diagnosis. Early recognition of coeliac disease, with appropriate implementation of a gluten-free diet, may reduce the incidence of benign and malignant complications associated with this condition.

Occupational skin disease in hairdressers

Hairdressers belong to an occupational group that is commonly affected by occupational skin disease, specifically contact dermatitis, which may be allergic or irritant and, less commonly, contact urticaria. Occupational contact dermatitis predominantly affects apprentices, and atopy is a recognized risk factor associated with a poor prognosis. Repetitive wet work leading to irritant contact dermatitis, followed by exposure to allergens and the development of allergic contact dermatitis, are the main factors contributing to occupational contact dermatitis. Once developed, it is often difficult to manage and is a cause of significant morbidity. Early education, training and prevention is the best approach to the management of this disorder that is endemic among hairdressers.

Reduction of use of latex gloves in food handlers: an intervention study

Frequent latex glove use is a risk factor for the development of latex allergy. With the increase in latex glove use, latex allergy has become more prevalent. There are a number of occupational groups in which the use of latex gloves is both inappropriate and even hazardous, including food handlers, where the hazard relates particularly to their latex-sensitive customers. The aim of this study was to assess both the use of latex gloves by food handlers and the impact of an intervention study on reducing latex glove use. This was done at the Queen Victoria Market in Melbourne, Australia. We found that 10 out of 30 stalls (33%) used latex gloves, and that following a short education program, this was reduced to 1 stall (3%, p=0.006). The potential to reduce latex glove use by using this intervention study was 93% (95% confidence interval of 54%-100%). We recommend that food handlers be educated during their training, not only about hygiene issues, but also about the appropriate type of glove to wear, in order to prevent both the development of a new occupational group at risk of becoming allergic to latex, but more importantly to protect their latex-sensitive customers.

Severe allergic contact dermatitis induced by paraphenylenediamine in paint-on temporary 'tattoos'

Paraphenylenediamine (PPD) is a black dye with well known sensitizing properties. Its increasing use as a skin paint to produce temporary 'tattoos' has led to recent reports of allergic contact dermatitis. Hitherto, such cases of allergic contact dermatitis due to PPD have been localized to the original site of application of the skin paint. We report two cases of severe allergic reactions to paint-on 'tattoos'. Both of these patients had no prior history of sensitivity to PPD, although case 2 had previously used permanent hair dyes. In both cases, the primary eruption at the 'tattoo' site was followed within days by a generalized eruption which ultimately required treatment with oral corticosteroids, because the initially prescribed topical corticosteroids proved ineffective.

Unexpected neurotoxicity of etoposide phosphate administered in combination with other chemotherapeutic agents after blood-brain barrier modification to enhance delivery, using propofol for general anesthesia, in a rat model

OBJECTIVE

Osmotic blood-brain barrier disruption (BBBD) increases brain and brain tumor delivery of chemotherapeutic agents, which results in increased efficacy against brain tumors. We previously noted that the use of propofol anesthesia for BBBD increased the percentage of successful disruptions, resulting in delivery of increased amounts of chemotherapeutic drugs. This study evaluated the neurotoxicity of combination chemotherapeutic administration with this enhanced delivery system.

METHODS

Osmotic BBBD was performed in Long-Evans rats with isoflurane (n = 11) or propofol (n = 90) anesthesia. Carboplatin and/or melphalan, methotrexate, or etoposide phosphate was administered intra-arterially (IA) after BBBD using propofol anesthesia. Animals were assessed for systemic and neurological toxicity. Animals were killed for neuropathological evaluation 30 days after treatment.

RESULTS

With propofol or isoflurane anesthesia, BBBD alone produced no systemic or neurological toxicity. Single agents were relatively non-neurotoxic when administered IA with BBBD, as were the combinations of carboplatin or melphalan with methotrexate. Etoposide phosphate in combination with any other agent was observed to be highly neurotoxic if both agents were administered after BBBD. Administration of etoposide phosphate before BBBD completely eliminated neurotoxicity, although acute pulmonary toxicity occurred with any combination of etoposide phosphate and methotrexate, regardless of the timing of administration.

CONCLUSION

Neurotoxicity was significantly increased for etoposide phosphate combination groups, particularly when both drugs were administered IA after BBBD. This increase in neurotoxicity may reflect on increase in drug delivery observed with propofol anesthesia. The neurotoxicity of IA administered etoposide phosphate with BBBD and propofol anesthesia could be minimized by administering etoposide phosphate IA before BBBD and administering carboplatin or melphalan IA after BBBD.

Safety and efficacy of a multicenter study using intraarterial chemotherapy in conjunction with osmotic opening of the blood-brain barrier for the treatment of patients with malignant brain tumors

BACKGROUND

The aim of this study was to determine the safety and efficacy of intraarterial chemotherapy with osmotic opening of the blood-brain barrier (BBB) for the treatment of malignant brain tumors when administered across multiple centers.

METHODS

Patients with primary central nervous system lymphoma (PCNSL), primitive neuroectodermal tumor (PNET), germ cell tumor, cancer metastasis to the brain, or low or high grade glioma were eligible. Prior to entry, magnetic resonance imaging or computed tomography brain scan, medical history, neurologic status, and Karnofsky performance status were reviewed at the coordinating center. Standardized anesthesia and intraarterial catheterization guidelines were followed by a multidisciplinary team at each center. Between March 1994 and November 1997, 5 universities treated 221 adult patients with intraarterial chemotherapy with or without osmotic opening of the BBB (2464 procedures).

RESULTS

Of evaluable patients with PCNSL, 40 of 53 (75%) achieved complete response (CR). All evaluable patients with PNET (n = 17), metastatic disease (n = 12), or germ cell tumor (n = 4) achieved stable disease (SD) or better. Of 57 evaluable patients with glioblastoma multiforme, 45 (79%) achieved SD or better. Asymptomatic subintimal tear occurred in 11 of 221 patients (5%), pulmonary embolism in 6 of 221 (2.7%), and renal toxicity in 4 of 221 (1.8%). One patient with extensive glioma expired within 48 hours after treatment.

CONCLUSIONS

Using standard guidelines and protocols, intraarterial chemotherapy with or without osmotic opening of the BBB is feasible across multiple centers with a low incidence of catheter-related complications. In patients with chemotherapy-sensitive tumors, such as PCNSL, PNET, germ cell tumor, and cancer metastasis to the central nervous system, enhanced delivery results in a high degree of tumor response, with an efficacy profile that is reproducible across multiple centers.

Some random-effects models for the analysis of matched-cluster randomised trials: application to the Swedish two-county trial of breast-cancer screening

BACKGROUND

In the Swedish two-county trial women aged 40-74 years from two counties in Sweden were randomised to invitation to mammographic screening for breast cancer.

METHODS

This paper uses random effects logistic regression models to analyse recent data from the trial. The analysis accounts for the structure of the trial, where small geographical units are randomised within larger geographical strata (blocks of two or three small units that are socio-economically similar).

RESULTS

Fixed effects and a variety of random effects models show a strong degree of agreement and yield a significant 29% or 30% reduction in breast-cancer mortality.

DISCUSSION

Fixed effects and random effects models agree for this example, because heterogeneity both between strata and within strata between clusters is small and because the effect of treatment does not vary much in different strata.

Peptide T blocks GP120/CCR5 chemokine receptor-mediated chemotaxis

We previously reported that certain short gp120 V2 region peptides homologous to vasaoactive intestinal peptide (VIP), such as "peptide T," were potent inhibitors of gp120 binding, infectivity, and neurotoxicity. The present study shows that synthetic V2-region-derived peptides have potent intrinsic chemotaxis agonist activity for human monocytes and also act as antagonists of high-affinity (0.1 pM) gp120-mediated monocyte chemotaxis. Selectivity is shown in that peptide T is more potent at suppressing M-tropic than T-tropic gp120 chemotaxis. Peptide T was also able to suppress monocyte chemotaxis to MIP-1beta, a chemokine with selectivity for CCR5 chemokine receptors, while chemotaxis of the more promiscuous ligand RANTES was not inhibited, nor was chemotaxis mediated by SDF-1alpha. In order to determine if peptide T mediated its gp120 antagonistic effects via modulation of CCR5 receptors, RANTES chemotaxis was studied using a CCR5 receptor-transfected HOS cell line. In this case, RANTES chemotaxis was potently inhibited by V2-region-derived short peptides. Peptide T also partially suppressed (125)I-MIP1-beta binding to human monocytes, suggesting action at a subset of MIP1-beta receptors. The V2 region of gp120 thus contains a potent receptor binding domain and synthetic peptides derived from this region modulate CCR5 chemokine receptor chemotactic signaling caused by either gp120 or chemokine ligands. The results have therapeutic implications and may explain recent clinical improvements, in that HIV/gp120 actions at CCR5 receptors, such as occur in the brain or early infection, would be susceptible to peptide T inhibition.

The proteolytic fragments of the Alzheimer's disease-associated presenilin-1 form heterodimers and occur as a 100-150-kDa molecular mass complex

Mutations in the presenilin (PS) genes are linked to early onset familial Alzheimer's disease (FAD). PS-1 proteins are proteolytically processed by an unknown protease to two stable fragments of approximately 30 kDa (N-terminal fragment (NTF)) and approximately 20 kDa (C-terminal fragment (CTF)) (Thinakaran, G., Borchelt, D. R., Lee, M. K., Slunt, H. H., Spitzer, L., Kim, G., Ratovitsky, T., Davenport, F., Nordstedt, C., Seeger, M., Hardy, J., Levey, A. I., Gandy, S. E., Jenkins, N. A., Copeland, N. G., Price, D. L., and Sisodia, S. S. (1996) Neuron 17, 181-190). Here we show that the CTF and NTF of PS-1 bind to each other. Fractionating proteins from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid-extracted membrane preparations by velocity sedimentation reveal a high molecular mass SDS and Triton X-100-sensitive complex of approximately 100-150 kDa. To prove if both proteolytic fragments of PS-1 are bound to the same complex, we performed co-immunoprecipitations using multiple antibodies specific to the CTF and NTF of PS-1. These experiments revealed that both fragments of PS-1 occur as a tightly bound non-covalent complex. Upon overexpression, unclipped wild type PS-1 sediments at a lower molecular weight in glycerol velocity gradients than the endogenous fragments. In contrast, the non-cleavable, FAD-associated PS-1 Deltaexon 9 sediments at a molecular weight similar to that observed for the endogenous proteolytic fragments. This result may indicate that the Deltaexon 9 mutation generates a mutant protein that exhibits biophysical properties similar to the naturally occurring PS-1 fragments. This could explain the surprising finding that the Deltaexon 9 mutation is functionally active, although it cannot be proteolytically processed (Baumeister, R., Leimer, U., Zweckbronner, I., Jakubek, C., Grünberg, J., and Haass, C. (1997) Genes & Function 1, 149-159; Levitan, D., Doyle, T., Brousseau, D., Lee, M., Thinakaran, G., Slunt, H., Sisodia, S., and Greenwald, I. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 14940-14944). Formation of a high molecular weight complex of PS-1 composed of both endogenous PS-1 fragments may also explain the recent finding that FAD-associated mutations within the N-terminal portion of PS-1 result in the hyperaccumulation not only of the NTF but also of the CTF (Lee, M. K., Borchelt, D. R., Kim, G., Thinakaran, G., Slunt, H. H., Ratovitski, T., Martin, L. J., Kittur, A., Gandy, S., Levey, A. I., Jenkins, N., Copeland, N., Price, D. L., and Sisodia, S. S. (1997) Nat. Med. 3, 756-760). Moreover, these results provide a model to understand the highly regulated expression and processing of PS proteins.

Altered gene expression for calpain/calpastatin system in motor neuron degeneration (Mnd) mutant mouse brain and spinal cord

The calcium-activated neutral proteases (CANP, calpains) have been implicated in both acute and chronic neurodegenerative processes. In the present study, we analyzed the in situ mRNA expression of calpain I and II and their endogenous inhibitor, calpastatin, in the motor neuron degeneration (Mnd) mutant mouse, which exhibits progressive dysfunction of the spinal cord and brain. As the disease progresses, the mutants show increasingly pronounced motor abnormalities which coincide with swelling of the spinal motor neurons, neocortex, hippocampal CA regions and cerebellar Purkinje cells. In situ hybridization studies show that the Mnd mice have a significantly higher level of calpain I, calpain II and calpastatin than the congenic controls in the following brain regions and cell types: hippocampal CA3 region, pyramidal cells, cerebellar Purkinje cells and spinal cord motor neurons. However, no differences in calpain or calpastatin mRNA levels are observed in glial and cerebellar granule cells of Mnd and control mice. Western blots and competitive RT-PCR analyses of brain and spinal cord homogenates are confirmative. Such altered gene expression in specific cell types of brain and spinal cord suggests the involvement of the calpain/calpastatin system.

Cellular expression and proteolytic processing of presenilin proteins is developmentally regulated during neuronal differentiation

We have determined the expression of the Alzheimer's disease-associated proteins presenilin-1 and presenilin-2 in primary cultures of rat hippocampal neurons. Neurons highly express presenilin-1 and presenilin-2, whereas both proteins were not detected in astrocytes. Further, we have analyzed the subcellular localization and expression in rat hippocampal neurons during development. Although presenilin proteins were localized predominantly to the endoplasmic reticulum in nonneuronal cells transfected with presenilin cDNAs, in neurons, presenilin proteins were also found in compartments not staining with antibodies to grp78(BiP). Presenilin-1 and presenilin-2 were predominantly detected in vesicular structures within the somatodendritic compartment with much less expression in axons. Polarized distribution of presenilin-1 and presenilin-2 differs slightly, with more presenilin-2 expressed in axons compared with presenilin-1. Presenilin expression was found to be developmentally regulated. Presenilin expression strongly increased during neuronal differentiation until full morphological polarization and then declined. No full-length presenilin-1 or presenilin-2 could be detected within cell lysates. At early developmental stages the expected approximately 34-kDa N-terminal proteolytic fragment of presenilin-1 and the approximately 38-kDa fragment of presenilin-2 were detected. Later during differentiation we predominantly detected a approximately 38-kDa fragment for presenilin-1 and a approximately 42-kDa fragment for presenilin-2. By epitope mapping, we show that these slower migrating peptides represent N-terminal proteolytic fragments, cleaved C-terminal to the conventional site of processing. It is noteworthy that both presenilin-1 and presenilin-2 undergo alternative proteolytic cleavage at the same stage of neuronal differentiation. Regulation of presenilin expression and proteolytic processing might have implications for the pathological as well as the biological function of presenilins during aging in the human brain.

Subcellular colocalization of the cellular and scrapie prion proteins in caveolae-like membranous domains

Results of transgenetic studies argue that the scrapie isoform of the prion protein (PrPSc) interacts with the substrate cellular PrP (PrPC) during conversion into nascent PrPSc. While PrPSc appears to accumulate primarily in lysosomes, caveolae-like domains (CLDs) have been suggested to be the site where PrPC is converted into PrPSc. We report herein that CLDs isolated from scrapie-infected neuroblastoma (ScN2a) cells contain PrPC and PrPSc. After lysis of ScN2a cells in ice-cold Triton X-100, both PrP isoforms and an N-terminally truncated form of PrPC (PrPC-II) were found concentrated in detergent-insoluble complexes resembling CLDs that were isolated by flotation in sucrose gradients. Similar results were obtained when CLDs were purified from plasma membranes by sonication and gradient centrifugation; with this procedure no detergents are used, which minimizes artifacts that might arise from redistribution of proteins among subcellular fractions. The caveolar markers ganglioside GM1 and H-ras were found concentrated in the CLD fractions. When plasma membrane proteins were labeled with the impermeant reagent sulfo-N-hydroxysuccinimide-biotin, both PrPC and PrPSc were found biotinylated in CLD fractions. Similar results on the colocalization of PrPC and PrPSc were obtained when CLDs were isolated from Syrian hamster brains. Our findings demonstrate that both PrPC and PrPSc are present in CLDs and, thus, support the hypothesis that the PrPSc formation occurs within this subcellular compartment.

mu-calpain activation and calpain-mediated cytoskeletal proteolysis following traumatic brain injury

Increasing evidence suggests that excessive activation of the calcium-activated neutral protease mu-calpain could play a major role in calcium-mediated neuronal degeneration after acute brain injuries. To further investigate the changes of the in vivo activity of mu-calpain after unilateral cortical impact injury in vivo, the ratio of the 76-kDa activated isoform of mu-calpain to its 80-kDa precursor was measured by western blotting. This mu-calpain activation ratio increased to threefold in the pellet of cortical samples ipsilateral to the injury site at 15 min, 1 h, 3 h, and 6 h after injury and returned to control levels at 24-48 h after injury. We also investigated the effect of mu-calpain activation on proteolysis of the neuronal cytoskeletal protein alpha-spectrin. Immunoreactivity for alpha-spectrin breakdown products was detectable within 15 min after injury in cortical samples ipsilateral to the injury site. The levels of alpha-spectrin breakdown products increased in a biphasic manner, with a large increase between 15 min and 6 h after injury, followed by a smaller increase between 6 and 24 h after the insult. No further accumulation of alpha-spectrin breakdown products was observed between 24 and 48 h after injury. Histopathological examinations using hematoxylin and eosin staining demonstrated dark, shrunken neurons within 15 min after traumatic brain injury. No evidence of mu-calpain autolysis, calpain-mediated alpha-spectrin degradation, or hematoxylin and eosin neuronal pathology was detected in the contralateral cortex. Although mu-calpain autolysis and cytoskeletal proteolysis occurred concurrently with early morphological alterations, evidence of calpain-mediated proteolysis preceded the full expression of evolutionary histopathological changes. Our results indicate that rapid and persistent mu-calpain activation plays an important role in cortical neuronal degeneration after traumatic brain injury. Our data also suggest that specific inhibitors of calpain could be potential therapeutic agents for the treatment of traumatic brain injury in vivo.

Decreased receptor-mediated calcium response in prion-infected cells correlates with decreased membrane fluidity and IP3 release

The most characteristic neuropathologic features of prion diseases are accumulation of PrPSc in the brain and vacuolation of neurons. Neuronal vacuolation suggests plasma membrane dysfunction. In an earlier study, we found that bradykinin (Bk)-stimulated Ca2+ responses in scrapie-infected ScN2a cells were reduced by 30 to 50% compared with uninfected N2a cells. In this study, we investigated the cause. The IP3 second-messenger response to Bk stimulation was reduced 90%, indicating that a defect occurs in the plasma membrane. Receptor-binding assays showed a 3- to 4-fold increase in Bk receptor numbers on ScN2a cells; however, their binding affinity was reduced 5- to 13-fold, which may account for the decreased IP3 and Ca2+ responses. These results argue that scrapie causes a more fundamental change in the properties of the plasma membrane. We verified this by fluorescence recovery after photobleaching (FRAP) analysis with a lipid probe that measures lateral membrane fluidity. A 7-fold reduction of fluidity was found. These results support the hypothesis that the conversion of PrPc to PrPSc or the accumulation of PrPSc in scrapie-infected cells alters the composition of their plasma membranes that secondarily causes the abnormal receptor-mediated function.

The corporate assault on the Food and Drug Administration

Current "regulatory reform" in the U.S. Congress is seeking to eliminate the Food and Drug Administration. The author discusses the forces behind this reform and traces the impact of campaign contributions from various industries opposed to FDA regulations, stock held by members of Congress in companies regulated by the FDA, and a variety of organizations with ties to House Speaker Newt Gingrich that have received donations from industries that Gingrich has helped in their efforts to loosen FDA regulations. The article also examines the myth that the FDA is an overzealous watchdog imposing unnecessary burdens on the companies that it regulates. The controversy over the cow hormone rBGH is given as an example.

Regional differences in gene expression for calcium activated neutral proteases (calpains) and their endogenous inhibitor calpastatin in mouse brain and spinal cord

The family of calpains (CANP or calcium activated neutral proteases) and their endogenous inhibitor calpastatin have been implicated in many neural functions; however, functional distinctions between the major calpain isoforms, calpain I and II, have not been clearly established. In the present study we analyzed the gene expression patterns for calpain I and II and calpastatin in mouse brain and spinal cord by measuring both their mRNA and protein levels. Our results show that the overall mRNA level measured by competitive reverse transcription polymerase chain reaction for calpain II is 15-fold higher and for calpastatin is three-fold higher than that for calpain I. Overall, both mRNA and protein expression levels for the calpains and calpastatin showed no significant difference between the spinal cord and the brain. The cellular distributions of mRNA for calpain I or calpastatin, measured by in situ hybridization, are relatively uniform throughout the brain. In contrast, calpain II gene expression is selectively higher in certain neuron populations including pyramidal neurons of the hippocampus and the deep neocortical layers, Purkinje cells of cerebellum, and motor neurons of the spinal cord. The motor neurons were the most enriched in calpain message. Motor neurons possessed 10-fold more calpain II mRNA than any other spinal cord cell type. The differential distribution of the two proteases in the brain and the spinal cord at the mRNA level indicates that the two calpain genes are differentially regulated, suggesting that they play different physiological roles in neuronal activities and that they may participate in the pathogenesis of certain regional neurological degenerative diseases.

Abnormal plasma membrane properties and functions in prion-infected cell lines

A long trail of evidence indicates that the formation of PrPSc or its accumulation causes the neuronal dysfunction and clinical features of prion diseases. The results of our current line of studies argue that the main neuropathological and clinical features of prion diseases are explained by altered ion channel function secondary to decreased plasma membrane fluidity. This kind of mechanism has the potential to functionally disconnect neuronal networks and cause neuronal vacuolation. Our laboratory is currently focusing its investigations on pathogenic mechanisms that have the potential to link the formation of PrPSc with plasma membrane abnormalities in prion diseases. In summary, the first hypothesis suggests that the conversion of PrPC to PrPSc affects plasma membrane fluidity directly, which secondarily alters the properties and functions of its components. In contrast, the second hypothesis argues that PrPSc accumulation alters the ability of chaperones to correctly fold plasma-membrane proteins during their synthesis, which directly affects the properties of nascent proteins and secondarily affects membrane fluidity. Our current investigations are attempting to determine which of these mechanisms are plausible and, then, which is primary.

Cinnamon allergy in a baker

Contact dermatitis in bakers is usually irritant in origin, but there are a large number of potential allergens to which bakers can be exposed. A case is presented of allergic hand dermatitis due to cinnamon.

The frequency of reactions to sunscreens: results of a longitudinal population-based study on the regular use of sunscreens in Australia

Six-hundred-and-three people aged 40 or more years, from Maryborough in central Victoria, were enrolled in a randomized longitudinal study, which required daily application of either a SPF 15+, broad-spectrum, water-resistant sunscreen cream or the cream base without the active ingredients. The study duration was 7 months, from September 1991 until April 1992. One-hundred-and-fourteen (18.9%) of these subjects developed an adverse reaction to the cream they were applying. Patch testing, photopatch testing and scratch testing with the ingredients of the creams revealed that only a small proportion (< 10%) of the inflammatory eruptions were allergic in nature. None of the people tested was allergic to the sunscreen active ingredients. History and examination findings, where available, suggested that the majority of adverse responses were consistent with an irritant reaction, both to the sunscreen preparation and the base cream control. A higher than expected proportion of the people who developed an adverse reaction had a personal history consistent with atopy. Other reactions included acneiform eruptions and contact urticaria. A frequency of reactions to sunscreen preparations of over 15% means that further work is necessary to improve both the formulation of such products, and the manner and conditions under which they are used, to ensure satisfactory compliance.

Thyrotropin response to thyrotropin-releasing hormone in patients with dementia of the Alzheimer type

Eleven patients with senile dementia of the Alzheimer type and 11 age-matched control subjects were given the thyrotropin-releasing hormone (TRH) test. The two groups did not differ with respect to peak thyrotropin (TSH) response or TSH levels at baseline, 20, 30, and 45 min after TRH injection. There were significant differences between the groups on Hamilton Depression Rating Scale scores (p < 0.03), although neither group met clinical criteria for depression. Items that were significantly different pertained to depressed mood, loss of interest, loss of insight, suicidal ideation, and obsessional symptoms.