bluuebunny/crossref_metadata_2025 huggingface dataset:
Winter Burning and the Reduction of Cornus sericea in Sedge Meadows in Southern Wisconsin
Authors: Middleton Beth
Published: March 2003

To control shrubs, which are increasing in dominance in wetlands worldwide, winter burning may be an important tool, especially from the perspective of minimizing urban hazards. The goal of this project was to determine if winter burning was successful in reducing the dominance (mean percentage cover and maximum height) of Cornus sericea in sedge meadows in southern Wisconsin, where shrubs proliferated after cattle were excluded. Experimental burn and control plots were set up within sedge meadows, including an ungrazed “reference” site that had been little, if ever, grazed and a “historically grazed” site, a recovery site that had not been grazed by cattle since 1973. None of the dominant species including C. sericea was significantly affected by burning for either mean percentage cover or maximum height (analysis of variance: no burning × species interaction). Both mean percentage cover and maximum height were only weakly related to burning (28.1 and 14.3% of the variability contributed to the cumulative percentage of the coefficient of determination, respectively) at both sites based on non‐metric multidimensional scaling analysis. Although species richness increased in burned plots in 1999 and 2000, no differences were apparent between pre‐burned and unburned plots in 1997 and unburned plots in 1999 and 2000 (analysis of variance: year × burning interaction). After burning in the ungrazed site, herbaceous species appeared that had not been detected for decades, including Chelone glabra and Lathyrus palustris. Exotic species were present in both the ungrazed reference and recovery site. Although winter burning treatments did not reduce the dominance of woody shrub species in the site recovering from cattle grazing, burning was useful in stimulating the maintenance of species richness in the ungrazed sedge meadow.
Complement activation in acquired and hereditary amyloid neuropathy
Authors: Hafer‐Macko Charlene E. , Dyck Peter J. , Koski Carol Lee
Published: March 2003

Abstract  The pathogenesis of the axonal degeneration in acquired or hereditary amyloidosis is unknown. In this immunohistochemistry study, we examined 20 sural nerve biopsies from individuals with amyloid neuropathy (14 acquired and 6 hereditary) for evidence of complement activation. Complement activation products were detected on and around amyloid deposits within peripheral nerves. We found no difference in the extent, location or pattern of complement activation products between the 2 forms of amyloidosis. The presence of early classical pathway activation markers in the absence of antibody in hereditary cases suggests an antibody‐independent activation of the classical pathway through binding of C1q. The lack of Factor Bb–suggested alternative pathway activation was not significant in these cases. The detection of C5b‐9 neoantigen on amyloid deposits demonstrated that the full complement cascade was activated. Complement activation on amyloid deposits and the generation of C5b‐9 in vivo may contribute to bystander injury of axons in the vicinity of amyloid deposits.
Effect of α‐tocopherol supplementation on the ultrastructural abnormalities of peripheral nerves in experimental diabetes
Authors: Sharma Ashutosh K. , Ponery Abdul S. , Lawrence Paul A. , Ahmed Ijaz , Bastaki Salim M.A. , Dhanasekaran Subramanian , Sheen Rajan S. , Adeghate Ernest
Published: March 2003

Abstract  Ultrastructural observations were made on myelinated fibers in the tibial nerves in order to investigate the beneficial effects of α‐tocopherol administration in streptozotocin‐diabetic rats. Male Wistar rats, aged 12 weeks and weighing between 250 g to 300 g were studied. Six onset control rats were used to obtain the baseline parameters for this strain and age. Further 3 groups—untreated diabetic animals, diabetic animals treated with α‐tocopherol, and age‐matched controls—were studied over a 3‐month period. In the diabetic animal, administration of α‐tocopherol resulted in a significant increase (p < 0.05) in total plasma vitamin E levels when compared with other groups. Myelinated fiber cross‐sectional area (p < 0.05), axonal area (p < 0.01) and myelin sheath area (p < 0.05) were significantly less in the tibial nerve of diabetic animals than in age‐matched controls, but not different from those of onset controls. In the α‐tocopherol treated diabetic animals, the values for these parameters were intermediate without showing significant difference when compared with age‐matched controls and untreated diabetics. The “g” ratio (axon to fiber area) did not differ between any experimental groups. The number of large myelinated fibers were less in the untreated diabetic animals, but in the α‐tocopherol‐treated diabetics, the values were significantly higher (p < 0.05) than with untreated diabetics and were similar to those of age‐matched controls. In conclusion, this ultrastructural study reiterated the fact that structural abnormalities of myelinated fibers occur in experimental diabetes and that α‐tocopherol administration may be useful in preventing the development of these abnormalities.
Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) In Diabetes: Two Different Patterns Of Response To IV IG
Authors: Cocito D , Ciaramitaro P , Isoardo G , Pipieri A , Barbero P , Durelli L.
Published: March 2003

OBJECTIVE: The finding of predominantly demyelinating polyneuropathies has been considered unusual in diabetic patients, however recent studies reported polyneuropathies satisfying electrophysiological criteria for diagnosis of CIDP (Gorson et al., 2000; Rotta et al., 2000) can be detected in diabetic patients. It is uncertain if this type of PN shows similar response to immunomodulating treatment as compared to other CIDP. In this study we evaluated response to IV IG in 10 diabetic patients with predominantly demyelinating polyneuropathy. PATIENTS AND METHODS: We included all diabetic patients with CIDP evaluated in our department from July 1999 to November 2000. 13 patients were found to be affected with predominantly demyelinating polyneuropathy; 3 of them refused IV IG. Sensory and motor disturbances according to Van Dijk et al. (1999) and nerve conduction studies (NCS) according to standard techniques were performed before IV IG treatment (T0) and 1 month (T1) and 6 months (T2) after IV IG. All patients underwent CSF examination and anti‐MAG, anti‐sulphatide and anti‐GM1 antibody assay. RESULTS: Increased CSF protein levels were found in 6 patients. No patients were positive for anti‐MAG, anti‐sulphatide or anti‐GM1 antibody assay. We did not detect significant clinical improvement after IV IG treatment, however there was improvement of motor deficit in 2 patients and of sensory score in 3. Six patients, 3 with increased CSF proteins level, had improvement on NCS, however there was not overall significant improvement of NCS abnormalities at T1. Patients with normal CSF protein levels had greater, although not significant, improvement on NCS than patients with increased protein levels. All patients with increased CSF protein levels deteriorated clinically or on NCS before T2. All patients with normal CSF protein levels remained stable on both items at T2. DISCUSSION: Our results confirmed low response of diabetic patients with demyelinating polyneuropathy to immunomodulating treatment, outlined by Gorson et al. (2000). In our study patients with normal CSF protein levels seem to have a better response to IV IG treatment probably reflecting a different pathogenesis as compared to patients with increased CSF protein levels. On the other hand, the high rate of relapse after IV IG treatment in patients with increased CSF protein levels seems to confirm the association of diabetes mellitus and CIDP in some patients.
Inflammatory Pain Reduction In Rats By Local Treatment With oATP, A Selective Inhibitor Of P2X7 ATP Receptor
Authors: Dell'Antonio G , Quattrini A , Baccalini R , Dal Cin E , Ferrero ME.
Published: March 2003

Peptide neurotransmitters, as substance P or ATP, are released during inflammatiory processes by the nerve endings of sensory fibers. ATP is also released from the cytoplasm of damaged cells at the site of inflammation. It acts at the level of many P2X subtypes of purinoreceptors. The receptor for extracellular ATP named P2Z/P2X7 is selectively blocked by the periodate oxidized ATP (oATP). We have hypothesized that P2X subunits present on peripheral sensory nerve terminals, able to initiate a nociceptive signal, could be blocked by local treatment with oATP, so inducing pain relief. Male inbred Fisher rats weighing about 250 g were used. Unilateral inflammation into rat hind paw was induced by intraplantar injection of Freund's complete adjuvant (FCA). The following signs of inflammation, from 3 to 48 h after FCA injection, were detected: increased paw volume, increased paw temperature and hyperalgesia. The latter was evaluated using an algesiometric test wich measured the paw pressure threshold (PPT, expressed in g). We treated some rats, bearing paw inflammation by 12 h, with local injection of 56 μM oATP. We showed a significant reduction of hyperalgesia in treated rats (PPT = 190 ± 2.3 in inflamed paw of oATP treated vs. PPT = 60 ± 1.6 in inflamed paw of untreated rats, at 60 min following oATP innoculation). We showed also that treatment with oATP was more efficient than treatment with diclofenac in reducing local inflammatory pain (PPT expressed as percentage of the maximum possible effect = 60 ± 0.5, at 120 min following intraplantar administration of oATP, vs. 25 ± 1.9 at the same time following intraplantar administration of diclofenac). The use of polyclonal antibody anti P2X7 receptor to perform immunohistochemical analysis of inflamed tissue, showed a reduction of receptor expression at the level of nerve endings in sections obtained from rat paw treated with oATP with respect to sections obtained from untreated rats. Such an effect was independent on the recruitment of immunocytes in inflamed tissue. Our results demonstrate that ATP exerts a key role in the pathophysiology of peripheral inflammation and that oATP may be effective in treating inflammatory pain.
Myelin Protein Zero Mutations In Inherited Neuropathies: The Recurrent Thr124Met IS Associated With A Distinct Phenotype
Authors: Di Maria E , Bellone E , Cassandrini D , Nobbio L , Balestra P , Bordo D , Grandis M , Schenone A , Ajmar F , Mandich P.
Published: March 2003

Mutations in the myelin protein zero gene (MPZ) were found associated with different forms of inherited peripheral neuropathies, both demyelinating (Charcot‐Marie‐Tooth type 1, congenital hypomyelination) and axonal (Charcot‐Marie‐Tooth type 2). Six mutations were reported in patients with Charcot‐Marie‐Tooth type 2 (CMT2); in particular, the Thr124Met variant is supposed to be a recurrent mutation. We describe a family with three subjects in which Thr124Met segregates with the disease. The index case was a 41‐year‐old woman with a severe impairment at the four limbs. Motor nerve conduction velocities were reduced at lower limbs and relatively conserved at upper limbs. The sural nerve biopsy showed mild to severe loss of myelinated fibres with relative sparing of small fibres. Several clusters of small regenerating fibres and few thinly myelinated fibres were observed. Direct sequencing of the MPZ coding sequence revealed a C/T transition resulting in a Thr/Met substitution at codon 124. The same variant was found in the affected aunt of the patient. The mutation seems to occur on a different genetic background with respect to the haplotypes to date associated with the disease. The position of the amino acid replaced by the mutation in the extracellular domain suggests that the substitution could act by affecting the interactions between the two facing molecules extending from opposite membrane layers. The complex relationship between the molecular damage induced by the protein zero mutations and the clinicopathological features of the related diseases will be addressed, and discussed in the light of the current pathophysiological models. Partially granted by MURST and Ateneo to FA, Ministero della Sanità to PM. The laboratory is a member of the European CMT Consortium.
The PHE64LEU Variant Of TTR Is Associated With A Late‐Onset Form Of Familial Amyloidotic Polyneuropathy Dominated By Motor Involvement
Authors: Ferrarini M , Fabrizi GM , Nardelli E , Polo A , Zanette GP , Cavallaro T , Rizzuto N.
Published: March 2003

Autosomal dominant Familial Amyloidotic polyneuropathy (FAP) is caused by mutations of transthyretin (TTR). The prototype is the “Portoguese” Val30Met variant characterized by a length dependent sensory‐motor and autonomic neuropathy with onset in the third‐fourth decade; it affects mostly the unmyelinated and small myelinated nerve fibers with deposits of TTR‐amyloid in the endo‐ and epineurium. Sensory or autonomic neuropathy is the first manifestation. Carpal tunnel syndrome (CTS), cardiac, renal, and ocular involvement may occur variably leading to phenotypic heterogeneity. In two unrelated Italian pedigrees originating from Apulia and Sicily we identified the Phe64Leu variant. In both pedigrees, the disorder manifested in the sixth‐seventh decade with weakness of hand/leg muscles and dysesthesias in the extremities; generalized weakness and atrophy were prevalent in the distal muscles and became rapidly disabling; fasciculations were prominent, affecting also the tongue in one case with dysarthria and dysphagia. Late symptoms/signs included weight loss, impairment of thermal, pain and position sense, intractable diarrhea and vomiting. Initial diagnoses had been various: CTS, Charcot‐Marie‐Tooth disease, Chronic Inflammatory Demyelinating Polyneuropathy. In the two probands a nerve biopsy disclosed severe loss of myelinated fibers with scattered distribution, few Wallerian degenerations and diffuse loss of unmyelinated fibers, without evidence of amyloid deposition. Phe64Leu had been reported in two other pedigrees of Italian origin associated with a similar clinical and pathological phenotype (Ferlini A et al., Clin Genet 1996); that raises the possibility of a “founder effect.” Analysis of informative polymorphisms at nucleotide positions 2422, 2537, 5610 and 5708 of the TTR gene disclosed in the identified pedigrees a common haplotype associated with Phe64Leu (haplotype II), suggesting that the mutation might actually have occurred once and then spread in different geographical areas.
In Vitro Binding ANTI‐GM1 IGM To GM1 Inhibition Pattern By Three Intravenous γ‐Globulin Preparations In Patients With Distal Lower Motor Neuron Syndrome
Authors: Ferrero B , Cavallo R , Imperiale D , Alpa M , Roccatello D , Pisacane A , Ravetti C.
Published: March 2003

Aim of the study: To evaluate the in vitro inhibition of different Intravenous γ‐Globulin (IVIgG) preparations and of their F(ab′)2 fragments on the anti‐GM1 IgM binding to GM1. Methods: Amounts of three commercially available IVIgG preparations (Sandoglobulin, Ig Vena and Flebogamma) were digested by 10 mg/mL pepsin acetate buffer. Dialyzed digests were gel filtrated by a Sephadex G‐150 column and PBS to obtain purified F(ab′)2 fragments. Two patients with a distal lower motor neuron syndrome (A.B., female with motor conduction blocks at the electrophysiological examination; P.M., male without motor conduction blocks) with high anti‐GM1 IgM titer (1:84,000 and 1:52,000) were studied. Serum amounts of these patients were mixed with increasing amounts (from 0.25 to 5 times IgG patient molar concentration) of the three IVIgG preparations or their gel filtrated F(ab′)2 fragments, or with 2% bovine serum albumin. One hundred μL of each mixture was incubated in microtiter wells coated with 500 ng/mL GM1 methanol solution. Peroxidase conjugated goat anti‐human IgM and O‐phenylenediamine solutions were added according to the ELISA procedure and anti‐GM1 IgM titer was calculated by absorbance at 490 nm, extrapolating the value from a standard curve. Each mixture percent of inhibition of anti‐GM1 IgM to GM1 was expressed as a ratio between the difference of anti‐GM1 titer before and after IVIgG or F(ab′)2 incubation and the baseline anti‐GM1 titer. Results: Intact IVIgGs were able to inhibit binding of anti‐GM1 IgM to GM1 in a quite dose‐dependent manner, but at a different extent either between patients than among different IVIgG preparations: in patient A.B. the inhibition ranged from 8% to 71% using Sandoglobulin, 2% to 54% using Ig Vena and 9% to 65% using Flebogamma, while in patient P.M. the inhibition ranged respectively 0% to 35%, 3% to 62% and 8% to 74%. Similar results were reached using F(ab′)2 fragments: in patient A.B. the inhibition ranged respectively from 7% to 76%, 5% to 68% and 8% to 59%, while in patient P.M. the inhibition ranged respectively from 1% to 40%, 5% to 59% and 10% to 81%. Conclusions: IVIgG preparations inhibit the in‐vitro binding of anti‐GM1 IgM to GM1 supplying a possible explanation of IVIgG therapy in‐vivo efficacy. This inhibition is due to F(ab′)2 fragments and probably involves an idiotypic ‐ anti‐idiotypic interaction, because the same IVIgG or F(ab′)2 preparations give different percent inhibition of anti‐GM1 to GM1 binding according to the treated patient anti‐GM1 idiotopic pattern.
Extracellular Matrix Remodeling In Peripheral Neuropathies
Authors: Massa R , Palumbo C , Panico MB , Morello M , Bernardi G , Modesti A.
Published: March 2003

The role of extracellular matrix (ECM) in the development and maintenance of the normal nervous tissue structure has been demonstrated. However, little is known about ECM modifications taking place in peripheral nerve pathology. This gap has prompted us to study the expression of several components of the peripheral nerve ECM in the major categories of human peripheral neuropathies. Normal and pathological sural nerve biopsies, including cases of CMT1, HNPP, CIDP and axonal neuropathies were studied by immunohistochemistry for the expression of collagen (COL) types I, III, IV, V, VI, laminin (LN), tenascin (TN), fibronectin (FN) and vitronectin (VN). The immunoreactivity of ECM proteins in pathologic nerves showed different patterns in relation to their distribution in normal nerves. Indeed, COL I and III, which are the main stromal components of the epineurium and endoneurium, respectively, showed increased expression in these compartments, generally in chronic neuropathies. COL IV, V, VI and LN localized mainly to basement membranes (BM) of Schwann cells, perineurial cells and blood vessels, showing increased deposition in the presence of BM redundancy. FN localized diffusely to the endoneurium and perineurium in control nerves and its expression increased in CIDP nerves. VN immunoreactivity was limited to several spots along the perineurium and epineurial vessels in normal nerve. However, in CIDP and in some cases of axonal neuropathy the VN signal was increased in the perineurium and appeared also in endoneurial vessels. Finally, TN was detected in the perineurium and the nodal/paranodal region in control nerve, while in some cases of CMT1 and CIDP it appeared to mark several internodes. These data, showing specific changes of the ECM components in peripheral neuropathies, suggest that a complex ECM remodeling is associated with mechanisms of nerve damage and repair. Supported by MURST‐COFIN 98 (n°86) and by CNR 98 (n°03081 CT04).
Peripheral Neuropathy And Monoclonal Igm Gammopathy: Clinical And Laboratory Data From A Neurological Unit In A General Hospital
Authors: Camerlingo M , Nemni R , Casto L , Mamoli A.
Published: March 2003

BACKGROUND: It has been known for decades that monoclonal IgM gammopathies are associated with peripheral neuropathies. However, available data are from ultraspecialized laboratories, while little is reported about their epidemiology. PATIENTS AND mETHODS: Since 1988 we have recorded a registry of the patients referred for a peripheral neuropathy. Database included clinical, electrophysiological, laboratory, immunological and pathological data. All the patients were followed‐up with clinical visits or at least phone interview every six months. In case of death we evaluated death certificates and contacted general practitioners. Results: In the period from 1988–1999 we saw and followed‐up 512 patients with clinical ascertained peripheral neuropathy. Of those patients, 35 (6.8%) had a MGUS: 18 IgG, 10 IgM, and 7 IgA. The patients with IgM paraprotein were all men, except 1 woman, aged 48 to 71 years at the onset of symptoms. Eight patients had a predominantly sensitive neuropathy and two patients a motor neuropathy. Of the 8 patients with sensitive neuropathy, 3 had a demyelinating disease and antiMAG antibodies, 4 an axonal disease and antisulphatide antibodies, and 1 an axonal neuropathy with both antiMAG and antisulphatide antibodies. The two patients with motor neuropathy had both an axonal disease and anti‐GM1 antibodies. The patients with sensory neuropathy were treated with periodic plasmaphoresis plus i.v. cyclophosphamide every 4–6 months. The patients with motor neuropathy were treated every month with i.v. immunoglobulins alternated with i.v. cyclophosphamide. Follow‐up of those patients lasted 12 to 108 months. Four patients died: 3 with antisulfatide antibodies because of a developing cancer (2 a primary hepatic cancer and 1 a bladder neoplasm) and 1 with anti‐GM1 antibodies for respiratory failure. The remaining patients showed a slowly progressive invalidating disease especially with the loss of hand ability. Conclusions: The patients with monoclonal IgM gammopathy are a minority among those observed because of a peripheral neuropathy in a General Hospital. Prognosis is severe either because of growing dependency or of life shortening (directly or for developing cancer). Aggressive therapies probably deserve multicentric studies.
Cryoglobulinemia is a frequent cause of peripheral neuropathy in undiagnosed referral patients
Authors: Gemignani Franco , Melli Giorgia , Inglese Cristina , Marbini Adriana
Published: March 2003

Abstract  Cryoglobulinemia represents an emerging cause of peripheral neuropathy, especially in Southern Europe, in view of its relationship with hepatitis C virus infection. In a series of 100 consecutive referral patients with uncharacterized peripheral neuropathies, we systematically investigated cryoglobulinemia to assess its diagnostic yield. The most frequent diagnosis was hereditary neuropathy (33%), 29% were acquired neuropathies of different types, and no cause could be identified in 27%. Cryoglobulinemic neuropathy was diagnosed in 11 patients (7 women and 4 men), aged 54–77 (mean = 63.5 years), most presenting with sensory polyneuropathy, often asymmetrical. Cryoglobulin was also detected in 2 additional patients in whom a final diagnosis of non‐Hodgkin lymphoma was made. Purpura was absent in 4 patients (and in 2 with lymphoma), or restricted to discrete manifestations in the remaining patients, which did not provide a clue to the diagnosis. Thus, search for cryoglobulin proves useful in a substantial number of undiagnosed peripheral neuropathies (11% to 13% in our series), even in the absence of typical skin lesions, and it is recommended as a first‐line investigation in patients with unexplained neuropathy presenting in middle to older age.
Excitability of human axons
Authors: Burke D , Kiernan MC , Bostock H
Published: March 2003

The excitability of human axons can be studied reliably using the technique of threshold tracking, which allows the strength of a test stimulus to be adjusted by computer to activate a defined fraction of the maximal nerve or muscle action potential. The stimulus current that just evokes the target response is considered the ‘threshold’ for that response. More useful than the resting threshold are other indices of axonal excitability derived from pairs of threshold measurements, such as refractoriness, supernormality, strength‐duration time constant and ‘threshold electrotonus’ (i.e. the changes in threshold produced by long‐lasting depolarizing or hyperpolarizing current pulses). Each of these measurements depends on membrane potential and on other biophysical properties of the axons. Together they can provide new information about the pathophysiology underlying abnormalities in excitability in neuropathy.
Paraneoplastic Peripheral Neuropathy Associated With Anti‐hu Antibodies. A Clinical And Electrophysiological Study Of 20 Patients
Authors: Camdessanche JP , Antoine JC , Honnorat J , Vial C , Petiot P , Convers P , Michel D.
Published: March 2003

Although paraneoplastic subacute sensory neuronopathy is the most frequent presentation of peripheral neuropathy in patients with anti‐Hu antibodies, other neuropathies have been reported. In order to investigate the clinical and electrophysiological manifestations of neuropathies associated with anti‐Hu antibodies, we conducted a retrospective study of 20 patients. For the electrophysiological study, each nerve was classified as normal, demyelinating, axonal/neuronal or axonal/ demyelinating. Peripheral neuropathy was the presenting symptom in 95% of patients. CNS and autonomic neuropathy were present in 40% and 30% of patients, respectively. The course of the neuropathy was acute, mimicking Guillain‐Barré syndrome in one patient (5%), and subacute (55%) or progressive (40%) in the others. Clinically, the neuropathy was sensory (70%), sensorimotor (25%) or motor (5%). At onset, symptoms were symmetrical (65%), asymmetrical (25%) or multifocal (10%). Pain was a predominant manifestation (80%). Amyotrophia and fasciculations were rare. The median Rankin's score was 2, three patients having an indolent form. Electrophysiology showed the axonal/neuronal pattern to be the most frequent (46.9% of studied nerves); an axonal/demyelinating or demyelinating pattern being seen in 18.3% and 4.9% of nerves, respectively. The axonal/neuronal pattern was more frequent in sensory nerves and the mixed axonal/demyelinating pattern more frequent in motor nerves (P < 0.01). A higher proportion of abnormal nerves correlated with a progressive course (P < 0.05) or a Rankin's score between 3 and 5 (P < 0.01). In patients with sensory neuropathy, 88.5% of sensory nerves were abnormal, mostly with an axonal/neuronal pattern. In addition, 47% of motor nerves were abnormal so that only four out of 14 patients with a clinically pure sensory neuropathy (28.6%) had an electrophysiological pattern typical of sensory neuronopathy. In patients with a sensorimotor neuro‐ pathy, 96.6% of sensory and 71% of motor nerves were abnormal. The only statistical difference between sensory and sensorimotor neuropathies was that patients with sensorimotor neuropathy had more frequent motor nerve involvement (P < 0.05) without differences concerning the distribution of the abnormal patterns. Needle neuromyography showed only limited evidence of motor neurone degeneration in both sensory and sensorimotor neuropathy. The present work shows that the typical clinical and electrophysiological pattern of subacute sensory neuronopathy is rarely encountered in patients with anti‐Hu antibody and that motor nerve involvement is frequently seen, even in the absence of a motor deficit. In addition to their potential pathophysiological involvement in the mechanism of the paraneoplastic neuropathy, these findings have practical consequences for the diagnosis of the disorder.
PERIPHERAL NEUROPATHY IN CHRONIC OCCUPATIONAL INORGANIC LEAD EXPOSURE: A CLINICAL AND ELECTROPHYSIOLOGICAL STUDY
Authors: Rubens O , Logina I , Kravale I , Eglite M , Donaghy M.
Published: March 2003

Background and Objectives: Traditionally the neuromuscular disorder associated with lead poisoning has been purely motor. This study assessed peripheral nerve function clinically and electrophysiologically in 46 patients with neuropathic features out of a total population of 151 workers with raised blood and/or urinary lead concentrations. Results: Average duration of occupational exposure for the neuropathic group ranged from 8–47 years (mean 21.7). Their mean blood lead concentration (SD) was 63.9 (18.3) microg/dl (normal <40), urinary lead 8.6 (3.3) microg/dl (normal <5.0), urinary coproporphyrins 66.7 (38.4) microg/g creatinine (20–80), urinary aminolaevulinic acid 1.54 (0.39) mg/g creatinine (0.5–2.5). All 46 had distal paraesthesiae, pain, impaired pin prick sensation, diminished or absent ankle jerks, and autonomic vasomotor or sudomotor disturbances. Reduced vibration sensation and postural hypotension were present in all 20 studied. None of these 46 patients had motor abnormalities. Motor conduction velocity and compound muscle action potential amplitudes were normal, with marginally prolonged distal motor latencies. Sensory nerve action potential amplitudes lay at the lower end of the normal range, and the distal sensory latencies were prolonged. No direct correlation was found between the biochemical variables, and the clinical or electrophysiological data. Conclusions: One additional patient was seen with shorter term exposure to lead fumes with subacute development of colicky abdominal pain, severe limb weakness, and only minor sensory symptoms. Unlike the patients chronically exposed to lead, he had massively raised porphyrins (aminolaevulinic acid 21 mg/g creatinine, coproporhyrins 2102 microg/g creatinine). Patients with unusually long term inorganic lead exposure showed mild sensory and autonomic neuropathic features rather than the motor neuropathy classically attributed to lead toxicity. It is proposed that the traditional motor syndrome associated with subacute lead poisoning is more likely to be a form of lead induced porphyria rather than a direct neurotoxic effect of lead.
STEROID EFFECTS ON THE GENE EXPRESSION OF PERIPHERAL MYELIN PROTEINS
Authors: Melcangi RC , Magnaghi V , Galbiati M , Martini L.
Published: March 2003

The present article summarizes recent observations obtained in our laboratory which clearly indicate that sex steroids exert relevant effects on the peripheral nervous system. In particular, the following important points have emerged: (1) Steroids exert stimulatory actions on the synthesis of the proteins proper of the peripheral myelin (e.g., glycoprotein Po and peripheral myelin protein 22) in vivo and on the Schwann cells in culture; (2) in many cases the actions of hormonal steroids are not due to their native molecular forms but rather to their metabolites (e.g., dihydroprogesterone and tetrahydroprogesterone in the case of progesterone; dihydrotestosterone and 5 alpha‐androstane‐3 alpha,17 beta ‐diol in the case of testosterone); (3) the mechanism of action of the various steroidal molecules may involve both classical (progesterone and androgen receptors) and nonclassical steroid receptors (GABA, receptor); and finally, (4) the stimulatory action of steroid hormones on the proteins of the peripheral myelin might have clinical significance in cases in which the rebuilding of myelin is needed (e.g., aging, peripheral injury, demyelinating diseases, and diabetic neuropathy).
BONE MARROW TRANSFER FROM WILD‐TYPE MICE REVERTS THE BENEFICIAL EFFECT OF GENETICALLY MEDIATED IMMUNE DEFICIENCY IN MYELIN MUTANTS
Authors: Maurer M , Schmid CD , Bootz F , Zielasek J , Toyka KV , Oehen S , Martini R.
Published: March 2003

Inherited demyelinating neuropathies are chronically disabling human disorders caused by various genetic defects, including deletions, single site mutations, and duplications in the respective myelin genes. We have shown in a mouse model of one distinct hereditary demyelinating neuropathy (heterozygous PO‐deficiency, PO±) that an additional null mutation in the recombination activating gene‐1 (RAG‐1‐‐) leads to a substantially milder disorder, indicating a disease modifying role of T‐lymphocytes. In the present study, we addressed the role of lymphocytes in the mouse model by reconstituting bone marrow of PO±/RAG‐1‐‐ mice with bone marrow from immunocompetent wild‐type mice. We compared the pathology and nerve conduction in double mutant mice (PO±/RAG‐1‐‐ on a C57BL/6 background) with that in double mutants after receiving a bone marrow transplant. We found that the milder demyelination seen in the lymphocyte‐deficient PO±/RAG‐1‐‐ mutants was reverted to the more severe pathology by reestablishing a competent immune system by bone marrow transfer. These data corroborate the concept that the immune system contributes substantially to the pathologic process in this mouse model and may open new avenues to ameliorate human hereditary neuropathies by exploiting immunosuppressive treatments.
MORPHOLOGY AND LIFE CYCLE EVENTS IN PYROPHACUS STEINII (SCHILLER) WALL ET DALE (DINOPHYCEAE)
Authors: Faust Maria A.
Published: March 2003

Cells of Pyrophacus steinii (Schiller) Wall et Dale are round and lens shaped and have an anteroposteriorly compressed theca. The epitheca has a truncated, conical horn and a hexagonally shaped apical pore plate with two arched slits positioned off center. The cingulum is equatorial, narrow, and deep. The hypotheca is flat. The sulcus is narrow, slightly curved, and recessed and does not reach the cell’s antapex. The plate formula in these specimens of P. steinii is Po, 8′, Oa, 13", 13C, 12"′, 3p, 3"", and 8S with a difference in the number of precingular (13") and postcingular (12"′) plates. No additional posterior intercalary plates were present (Oap). Pregametic stages of P. steinii were observed during cell division via binary fission, with formation of two cells and multiple division with formation of four and eight cells. These newly formed cells were pale in color and were enclosed in double‐layered hyaline membrane. Gametes with gymnodinoid morphology were observed within the parental cells. Planozygotes are large and round and enclosed in double‐layered hyaline membrane. Mature cell forms are brown with a microgranular cytoplasm, storage bodies, and a red accumulation body. The hypnozygote exhibits triple‐layered hyaline membrane, irregularly shaped and comparable with bulbous processes of Tuberculodinium vancampoae Rossigol resting cysts. Division within a hypnocyst of P. steinii involves shedding the parental theca and the development and emergence of two daughter cells with the size and morphology of pregametic cells.
CELL DIVISION AND MORPHOGENESIS OF THE CENTRIC DIATOM CHAETOCEROS DECIPIENS (BACILLARIOPHYCEAE) I. LIVING CELLS
Authors: Pickett‐Heaps Jeremy D.
Published: March 2003

Like other diatoms, living cells of Chaetoceros decipiens Cleve expand lengthwise before they divide. During prophase, the nucleolus disappears in about 30 s. The spindle is very small but anaphase chromosome separation can be seen. Following rapid cleavage, the protoplasts contract, plasmolyzing slightly and transforming the cleavage furrow into a lens‐shaped opening between daughter cells. During valve initiation, the surface of the furrow is molded slightly into the shape of the mature valve face. Then daughter cells expand further, becoming fully turgid as they open the slots in the girdle bands through which the setae will grow. Soon, delicate protrusions push through the girdle bands and develop into the setae, which are very sensitive: any disturbance will immediately stop their steady growth. Healthy setae display soft, mobile tips and tiny organelles (mitochondria) actively move along the lumen. Their curvature and uniform diameter is controlled during growth with exquisite precision, and in optimal conditions, they can become very long. At their initiation, cells appear fully turgid; however, many cells soon become slightly plasmolyzed during seta growth. This observation strongly suggests that turgor pressure cannot be responsible for driving extension; the possible mechanism is discussed in the following paper.
THE EVOLUTION OF THERMOTOLERANCE IN HOT SPRING CYANOBACTERIA OF THE GENUS SYNECHOCOCCUS
Authors: Miller S.R. , Castenholz R.W.
Published: March 2003

The extension of ecological tolerance limits may be an important mechanism by which microorganisms adapt to novel environments, but it may come at the evolutionary cost of reduced performance under ancestral conditions. We combined a comparative physiological approach with phylogenetic analyses to study the evolution of thermotolerance in hot spring cyanobacteria of the genus Synechococcus. Among the twenty laboratory clones of Synechococcus isolated from collections made along an Oregon hot spring thermal gradient, four different 16S ribosomal RNA gene sequences were identified. Phylogenies constructed using these sequence data indicated that the clones were polyphyletic but also that three of the four sequence groups formed a clade. Differences in thermotolerance were observed for clones with different 16S rRNA gene sequences, and comparison of these physiological differences within a phylogenetic framework provided evidence that more thermotolerant lineages of Synechococcus evolved from less thermotolerant ancestors. The extension of the thermal limit in these bacteria was correlated with a reduction in thermal niche breadth, which may have implications for the geographic distributions of these organisms. This study illustrates the utility of using phylogenetic comparative methods to investigate how evolutionary processes have shaped historical patterns of ecological diversification in microorganisms.
PHYLOGENY OF ATLANTIC SPECIES OF GRACILARIACEAE (RHODOPHYTA) BASED ON SMALL SUBUNIT RIBOSOMAL GENE SEQUENCING
Authors: Bellorin A. M. , Oliveira M.C. , Oliveira E.C.
Published: March 2003

The complete small subunit ribosomal nuclear gene (ssu rDNA) sequence was determined for nine species of Gracilaria and one species of Gracilariopsis which are common on the American Atlantic waters. The sequences were aligned using the secondary structure as reference, including the published sequences of nine other species of Gracilariaceae. A matrix of 1736 sites was constructed with a proportion of 91% invariable sites and very few assumed indels events. All the inferred trees show three main lineages: 1) the strongly divergent lineages of Gracilariopsis; 2) the austral genera Curdiea/Melanthalia; and 3) the lineage of Gracilaria sensu stricto. The later encompasses the following groups: 1) Gracilaria chilensis from the Pacific ocean; 2) a group of cylindrical tropical species with “henriquesiana” spermatangial type; 3) a group of warm temperate cylindrical species with “verrucosa” spermatangial type; and 4) a group of flattened tropical species with mainly “textorii” spermatangial type. The relationship of a species described as Gracilaria pauciramosa from Venezuela was not inequivocally solved. The inferred phylogenetic groups are congruent with morphology and quality of agar.
CULTIVATION STUDIES OF GIGARTINA SKOTTSBERGII IN SOUTHERN CHILE
Authors: Buschmann A.H. , Correa J.A. , Westermeier R.
Published: March 2003

In Chile, the demand for carrageenophytic algae has increased significantly in recent years. The preferred species is Gigartina skottsbergii, with landings of 26,181 tons in 1998. To avoid a possible overexploitation the development of cultivation technologies is needed. In this study we present a critical view of published and new information to propose the best culture strategy for this species. The results indicate that viable spores are seasonally available only during winter, with tetraspore germination rates of ca. 40%. Germination of carpospospores is lower than 20%. Growth in tanks can be as high as 1% day−1 and high nutrient concentrations (N and P) must be added. Gigartina also present a high and unique regeneration capacity. Field experiments indicate that Gigartina can be cultured in rope systems, where the inoculum can be tissue fragments. These results indicate that vegetative propagation techniques can be used for the massive culture of Gigartina, but selection of a high growing strain remains as one of the future challenges.
MORPHOLOGY AND PHOTOSYNTHESIS OF CAULERPA (CHLOROPHYTA) IN RELATION TO GROWTH FORM
Authors: Collado‐Vides Ligia , Robledo Daniel
Published: March 2003

Morphological and photosynthetic performance were analyzed in species of the genus Caulerpa from an exposed coral reef and a sheltered reef lagoon. Morphological characters, such as distance between modules, number of modules, stolon branches and rhizoid clusters per centimeter of stolon, indicated a uniformity among species within a specific habitat. “Guerilla,” or diffusive, growth forms were characteristic for lagoon species and “phalanx,” or compact, growth forms for reef species. Differences in photosynthesis were found between Caulerpa species. Sun‐tolerant species were found on the reef, and both sun‐ and shade‐tolerant species were present in the lagoon. In the lagoon, shade‐tolerant species, such as C. lanuginosa J. Agardh, were found growing in the understory, and sun‐tolerant species, such as C. paspaloides (Bory) Greville, formed the canopy. C. cupressoides (West in Vahl) C. Agardh was the only species found in both environments; it showed higher photosynthetic rates and a compressed morphology when growing on the reef and lower photosynthetic rates and expanded morphology for lagoonal ramets. These results suggest that C. cupressoides possesses a broad phenotypic ability to acclimate to lagoonal and reef settings in comparison to other Caulerpa species, enhancing its ecological success in this particular system.
SPATIAL PATTERNS AND ECOLOGICAL DETERMINANTS OF BENTHIC ALGAL ASSEMBLAGES IN MID‐ATLANTIC STREAMS, USA
Authors: Pan Yangdong , Stevenson R. Jan , Hill Brian H. , Kaufmann Philip R. , Herlihy Alan T.
Published: March 2003

We attempted to identify spatial patterns and determinants for benthic algal assemblages in Mid‐Atlantic streams. Periphyton, water chemistry, stream physical habitat, riparian conditions, and land cover/use in watersheds were characterized at 89 randomly selected stream sites in the Mid‐Atlantic region. Cluster analysis (TWINSPAN) partitioned all sites into six groups on the basis of diatom species composition. Stepwise discriminant function analysis indicated that these diatom groups can be best separated by watershed land cover/use (percentage forest cover), water temperature, and riparian conditions (riparian agricultural activities). However, the diatom‐based stream classification did not correspond to Omernik’s ecoregional classification. Algal biomass measured as chl a can be related to nutrients in habitats where other factors do not constrain accumulation. A regression tree model indicated that chl a concentrations in the Mid‐Atlantic streams can be best predicted by conductivity, stream slope, total phosphorus, total nitrogen, and riparian canopy coverage. Our data suggest that broad spatial patterns of benthic diatom assemblages can be predicted both by coarse‐scale factors, such as land cover/use in watersheds, and by site‐specific factors, such as riparian conditions. However, algal biomass measured as chl a was less predictable using a simple regression approach. The regression tree model was effective for showing that ecological determinants of chl a were hierarchical in the Mid‐Atlantic streams.
THE RELEASE OF COPPER‐COMPLEXING LIGANDS BY THE BROWN ALGA FUCUS VESICULOSUS (PHAEOPHYCEAE) IN RESPONSE TO INCREASING TOTAL COPPER LEVELS
Authors: Gledhill Martha , Nimmo Malcolm , Hill Steve J. , Brown Murray T.
Published: March 2003

The growth of Fucus vesiculosus L. germlings in chemically defined culture media containing a range of Cu concentrations (20–1000 nM) was monitored simultaneously with measurement of the Cu speciation in the media by competitive equilibrium‐adsorptive cathodic stripping voltammetry. Fucus vesiculosus germlings were found to exude Cu‐complexing ligands with conditional stability constants of the order of 1.6 × 1011. Ligand concentrations increased with increasing total dissolved Cu concentrations (CuT) until a concentration of 500–800 neq Cu·L−1 was reached. Concentrations of the ligand exceeded CuT in treatments containing 20 and 100 nM Cu, were similar to CuT in the 500‐nM Cu treatment, but were less than CuT in the 1000‐nM treatment. Therefore, [Cu2+] were calculated to be at concentrations of 10−11− 10−10 M in the 20‐ and 100‐nM treatments, 10−9 M in the 500‐nM treatment, and 10−7 M in the 1000‐nM treatment. Growth rates were lowest at Cu2+ concentration > 10−9. These results are discussed within the context of the potential roles for exuded copper‐complexing ligands.
SCYTONEMIN, A CYANOBACTERIAL SHEATH PIGMENT, PROTECTS AGAINST UVC RADIATION: IMPLICATIONS FOR EARLY PHOTOSYNTHETIC LIFE
Authors: Dillon Jesse G. , Castenholz Richard W.
Published: March 2003

During the Precambrian, ultraviolet (UV) radiation reaching the Earth’s surface, including UVC wavelengths (190–280 nm), was considerably higher than present because of the lack of absorbing gases (e.g. O2 and O3) in the atmosphere. High UV flux would have been damaging to photosynthetic organisms exposed to solar radiation. Nevertheless, fossil evidence indicates that cyanobacteria‐like ancestors may have evolved as early as 3.5 × 109 yr ago, and were common in shallow marine habitats by 2.5 × 109 years ago. Scytonemin, a cyanobacterial extracellular sheath pigment, strongly absorbs UVC radiation. Exposure to high‐irradiance conditions caused cells to synthesize scytonemin and resulted in decreased UVC inhibition of photosynthetic carbon uptake. It was further demonstrated that scytonemin alone was sufficient for substantial protection against UVC damage. This represents the first experimental demonstration of biological protection against UVC radiation in cyanobacteria. These results suggest that scytonemin may have evolved during the Precambrian and allowed colonization of exposed, shallow‐water and terrestrial habitats by cyanobacteria or their oxygenic ancestors.
MOLECULAR PHYLOGENETIC ANALYSIS OF THE HETEROTROPHIC CHRYSOPHYTE GENUS PARAPHYSOMONAS (CHRYSOPHYCEAE), AND THE DESIGN OF rRNA‐TARGETED OLIGONUCLEOTIDE PROBES FOR TWO SPECIES
Authors: Caron David A. , Lim Ee Lin , Dennett Mark R. , Gast Rebecca J. , Kosman Carol , DeLong Edward F.
Published: March 2003

Nanoflagellate protists are algae and protozoa (2– 20 μm in size) that play important ecological roles in freshwater and marine microbial communities as primary producers and as consumers of prokaryotic and eukaryotic prey. There is little biogeographical information for most of these minute protists despite their significant role in aquatic food webs. In addition, the evolutionary relationships among some of these species and their affinities to other protistan taxa are unclear. These circumstances are largely a consequence of the fact that small protists possess few readily apparent morphological features on which to base taxonomic and phylogenetic schemes and with which to identify them in natural assemblages. As an alternative approach for addressing these issues, we sequenced the small‐subunit ribosomal RNA genes of four species of the colorless chrysophyte genus Paraphysomonas. A phylogenetic analysis based on that sequence information was performed, and oligonucleotide probes for two commonly occurring species of Paraphysomonas were designed and tested. Phylogenetic analyses of these four species confirmed the affinity of the genus Paraphysomonas with other chrysophyte species. High sequence similarity among three of the species (P. imperforata Lucas, P. bandaiensis Takahashi, and P. foraminifera Lucas) supported a previous phylogenetic grouping of these species based on the morphology of the scales produced by these species. In particular, sequence similarity between P. imperforata and P. foraminifera indicated that this speciation was a recent evolutionary event. However, a fourth species (P. vestita (Stokes) de Saedeleer) possessing similar scale morphology to P. bandaiensis, P. imperforata, and P. foraminifera showed considerable sequence dissimilarity in comparison to these latter three species. Oligonucleotide probes were successfully designed for the species P. imperforata and P. bandaiensis and applied together with a recently developed quantitative in situ hybridization procedure. The development of species‐specific oligonucleotide probes for these nanoflagellate species and their application for counting nanoflagellates in natural water samples provide tools for studying these ecologically important species.