The Roussy-Lévy family: from the original description to the gene

In 1926, Roussy and Lévy described a large family whose members manifested an early onset dominantly inherited gait ataxia, pes cavus, and areflexia, which was eventually associated with distal muscle atrophy, postural tremor, and minor sensory loss. Slow nerve conduction and demyelination of nerve fibers with onion bulb formations in nerve biopsy specimens led to the Roussy-Lévy syndrome (RLS) being considered a variant of demyelinating Charcot-Marie-Tooth disease (CMT-1). In the present article, we report on the long-term follow-up, on nerve biopsy findings, and on the underlying molecular genetic defect in members of the original family studied by Roussy and Lévy. All patients were able to walk during their seventh decade of life. Morphologically, a chronic demyelinating neuropathy with the remarkable aspects of a focally hypertrophic myelin sheath and major loss of myelinated fibers was observed in nerve biopsy specimens of 3 members of this family. Molecular genetic testing identified a previously unknown heterozygous missense point mutation which yielded an Asn131Lys substitution in the extracellular domain of the myelin protein zero (P0). These findings show that the Roussy-Lévy family belongs to the CMT-1B subtype and has original morphological and genetic features.

Production and utilization of polyclonal antibodies against nisin in an ELISA and for immuno-location of nisin in producing and sensitive bacterial strains

Specific nisin polyclonal antibodies (PAb) were produced in rabbits using nisin Z produced by Lactococcus lactis subsp. lactis biovar diacetylactis UL 719. Antisera were obtained from white female New Zealand rabbits that were first immunized with a nisin Z-keyhole limpet haemocyanin conjugate and boosted with free nisin Z. Nisin-specific PAb were purified by affinity chromatography with a yield of 15 mg specific antinisin 100 ml-1 serum. The detection limit of the ELISA test for nisin Z was 0.75 ng ml-1 in buffer but was 1.7 and 3.5 ng ml-1 in milk and complex media broth spiked (5, 10, 20 microg ml-1) with nisin Z, respectively. In nisin Z-spiked samples, the average concentration was between 90 and 107% of actual added amount. In contrast, when the bioassay (microtitration method) was used, only 50-63% of nisin Z biological activity could be detected. In addition, the affinity-purified nisin PAb, antirabbit IgG gold conjugate and transmission electron microscopy were successfully used to locate nisin Z on producing cells and to observe its bactericidal effects against sensitive cells.

Plasma homocysteine, aortic stiffness, and renal function in hypertensive patients

Hyperhomocysteinemia has been associated with both vascular structure alterations and vascular clinical end points. To assess the relation between plasma homocysteine, structure and function of large arteries, and the presence of clinical vascular disease, we investigated a population of 236 hypertensive patients. We estimated arterial stiffness by measuring the carotid-femoral pulse wave velocity. Total plasma homocysteine was determined by fluorometric high-performance liquid chromatography. The presence of cardiovascular disease was defined on the basis of clinical events, including coronary heart disease, cerebrovascular disease, and peripheral vascular disease. In this population, pulse wave velocity was positively correlated with homocysteine, even after adjustments for age, mean blood pressure, extent of atherosclerosis, and creatinine clearance (P=0.016). Analysis of variance showed statistically significant differences between the mean values of homocysteine, creatinine clearance, and pulse wave velocity according to the extent of atherosclerosis, with an increase in these 3 parameters concomitant with an increase in the number of vascular sites involved with atherosclerosis. In conclusion, in hypertensive patients the levels of homocysteine are strongly and independently correlated to arterial stiffness measured by aortic pulse wave velocity. Plasma homocysteine, creatinine clearance, and aortic pulse wave velocity are higher in patients presenting with clinical vascular disease. These results suggest that the evaluation of aortic distensibility and homocysteine levels can help in cardiovascular risk assessment in hypertensive populations.

Persistent mitochondrial dysfunction and perinatal exposure to antiretroviral nucleoside analogues

BACKGROUND

Zidovudine is commonly administered during pregnancy to prevent mother-to-child HIV-1 transmission. We investigated mitochondrial toxic effects in children exposed to zidovudine in utero and after birth.

METHODS

We analysed observations of a trial of tolerance of combined zidovudine and lamivudine and preliminary results of a continuing retrospective analysis of clinical and biological symptoms of mitochondrial dysfunction in children born to HIV-1-infected women in France. Mitochondrial dysfunction was studied by spectrophotometry and polarography of respiratory-chain complexes in various tissues.

FINDINGS

Eight children had mitochondrial dysfunction. Five, of whom two died, presented with delayed neurological symptoms and three were symptom-free but had severe biological or neurological abnormalities. Four of these children had been exposed to combined zidovudine and lamivudine, and four to zidovudine alone. No child was infected with HIV-1. All children had abnormally low absolute or relative activities of respiratory-chain complexes I, IV, or both months or years after the end of antiretroviral treatment. No mutation currently associated with constitutional disease was detected in any patient.

INTERPRETATION

Our findings support the hypothesis of a link between mitochondrial dysfunction and the perinatal administration of prophylactic nucleoside analogues. Current recommendations for zidovudine monotherapy should however be maintained. Further assessment of the toxic effects of these drugs is required.

Fatal case of dichloromethane poisoning

A 47-year-old man was found dead in a factory where dichloromethane (DCM) tanks were stocked. He was making an inventory of the annual stock of DCM contained in several tanks (5- to 8000-L capacity) by transferring the solvent into an additional tank with the help of compressed air. During this operation, one of the tanks overflowed and the man, who was not wearing any protection, was intoxicated. Autopsy showed digestive, suprarenal, and liver bleeding. Blood was also found in the trachea. DCM was identified by headspace gas chromatography-mass spectrometry (GC-MS). A headspace gas chromatography-flame ionization detection technique (GC-HS-FID) optimized for quantitation in biological fluids, organs and viscera was established at autopsy. The following concentrations of DCM were found: blood (150 mg/L), urine (2.0 mg/L), gastric content (5.6 mg/L), brain (122 mg/kg), fat (99 mg/kg), liver (44 mg/kg), lung (20 mg/kg), and kidney (15 mg/kg). A study of the storage stability of DCM was carried out on these samples. Ethanol production was measured in some organs. The results are discussed in light of the rarity of existing literature.

Reinnervation of denervated lumbar ventral roots and their target muscle by thoracic spinal motoneurons via an implanted nerve autograft in adult rats after spinal cord injury

Intraspinally implanting a nerve autograft (NAG) to promote axonal regeneration toward periphery was investigated as a surgical treatment for spinal cord injury in adult rats. Fifteen animals underwent a left hemisection of the spinal cord at T12 level and an intradural section of all ipsilateral lumbar ventral roots. In repaired animals (n = 9), the electrophysiologically selected left L3 and L4 lumbar ventral roots supplying the quadriceps muscle were anastomosed to a NAG. The NAG was taken from the right peroneal nerve and then ventrolaterally implanted into the cord at a level 7 mm rostral to the hemisection. In the control group (n = 6), sectioned lumbar ventral roots were left unrepaired. Nine months later, the animals were assessed with clinical, electrophysiological, and histological examinations. Muscle action potential and motor evoked potential were obtained from the denervated/reinnervated quadriceps in all repaired animals, with a mean amplitude of 918.3+/-328.9 microV and 215.8+/-39.7 microV, respectively. Horseradish peroxidase retrograde labeling from the denervated/repaired lumbar ventral roots, performed in five repaired animals, showed that the mean of labeled neurons, ipsilaterally located in the thoracic ventral horn near the implantation site, was 145.8+/-111.7. Histological analysis showed numerous myelinated axons in the NAG and denervated/repaired lumbar ventral roots of all repaired animals. The study of neuromuscular junctions furthermore confirmed numerous newly formed endplates appearing in the denervated/reinnervated quadriceps. These changes were absent in the control animals. These data indicate that the rostral thoracic spinal motoneurons can innervate the caudal denervated/repaired lumbar ventral roots and the target quadriceps via an implanted NAG, thereby inducing some functional recovery in adult rats after lower thoracic spinal cord injury.

Digoxigenin-labeled probe for rapid identification of nisinogenic Lactococcus lactis strains

From the nisZ gene sequence, a non-radioactive digoxigenin-labeled DNA probe, was tested for detection of nisin-producing strains using polymerase chain reaction amplification. The digoxigenin-labeled DNA probe clearly discriminated between nisin-producing and non-producing strains with a high degree of sensitivity and specificity. By agarose gel electrophoresis, 1.4 ng of nisin DNA was detected using the digoxigenin-labeled DNA probe compared with 11 ng using direct polymerase chain reaction amplification. A colony hybridization method using digoxigenin-labeled DNA to selectively detect nisinogenic bacteria showed that the nis-probe was specific and did not react with any other non-bacteriocinogenic and non-nisinogenic strains.

Clinicopathologic findings and prognosis of chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

To evaluate the clinicopathologic features and prognostic factors of 100 patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

Comparison of clinical and biopsy findings with functional score evaluated an average of 6 years after referral.

RESULTS

CIDP followed a relapsing course in 14% of the patients and a progressive course in 45%. After progressive onset, little change was noted during follow-up in the others. Five patients had symptomatic involvement of the CNS. Teased fiber preparations of nerve biopsy specimens showed that 68 patients had purely demyelinative lesions, 20 had mixed axonal and demyelinative lesions, and 5 had predominantly axonal lesions. Axonal loss was a common finding, with 47% of the patients retaining less than half of the normal density of fibers. Inflammatory infiltrates, found in 18 samples, were prominent only in 4. Of the 83 patients evaluated an average of 6 years after onset, 56 were in good condition; 24 had deteriorated and failed to respond to treatment, including 9 patients who died as a consequence of their neurologic deficit. Progressive course, CNS involvement, high proportion of fibers showing active demyelination on nerve biopsy, and axonal loss overall correlated with higher disability.

CONCLUSION

Axonal loss is the major long-term pejorative prognostic factor in CIDP.

Calcium-regulating hormones, bone mineral content, breaking load and trabecular remodeling are altered in growing pigs fed calcium-deficient diets

Studies on calcium nutrition in appropriate large animal models can be directly relevant to humans. We have examined the effect of dietary Ca deficiency on various bone and bone-related variables, including plasma markers, histomorphometry, mineral content and breaking strength in pigs. Three groups of eight 38-d-old female pigs were fed adequate (0.9%; control), low (0.4%; LCa) or very low (0.1%; VLCa) Ca diets for 32 d. Plasma Ca significantly decreased over time only in the VLCa-deficient pigs. The concentrations of the parathyroid hormones (PTH) and calcitriol increased as Ca deficiency developed, and the plasma PTH and calcitriol levels varied inversely with dietary Ca. The total bone ash contents, bending moments, trabecular bone volume and the mineral apposition rate all decreased as the calcium intake decreased. The osteoclast surface areas were greater than those of controls in both Ca-deficient groups, whereas the osteoblast surface areas were greater only in the VLCa group. The plasma osteoblast-related markers (alkaline phosphatase, carboxy-terminal propeptide of type I procollagen and osteocalcin) were either greater or unaffected in the Ca-deficient pigs. The results indicate that deficient bone mineralization combined with an increased bone resorption led to bone loss and fragility. The differences in the changes in bone cells (number and activity) between LCa and VLCa groups might be due to differences (time and extent) of circulating PTH and calcitriol. The defective mineralization in both Ca-depleted groups resulted mainly from the lack of Ca because their osteoblast activity was either maintained or stimulated. The results also underline the progressive sensitivity of pigs to Ca supply and the usefulness of this model.

[XII cranial nerve pseudoneurinoma due to spontaneous fibrous transformation of an aneurysm of the vertebral artery]

The authors report an exceptional case report of tumor like evolution of a completely thrombosed aneurysm of the right vertebral artery suggestive of neurinoma of the XII nerve. We describe CT, MRI, MR-angiography. The diagnosis has been established by pathologic study after surgical extraction. Our case demonstrate the possibility of growth of totally thrombosed aneurysms and we discuss various mechanisms.

The Th1 to Th2 shift induced by Schistosoma mansoni does not exacerbate murine aids (MAIDS)

Schistosoma mansoni infection in mice is associated with a switch from a Th1 to a Th2-type cytokine response. The role of Th1 and Th2 responses in immune dysregulations associated with AIDS and murine AIDS (MAIDS) is controversial, but a Th2 bias could be associated with disease progression, raising the hypothesis that helminth infections might accelerate the retroviral disease progression. Here, we used the murine model of AIDS to evaluate the course of the viral disease during co-infection with S. mansoni. C57BL/6 mice were infected with S. mansoni cercariae 8 weeks before intravenous challenge with the LP-BM5 retroviral complex. MAIDS did not progress faster in co-infected mice, in terms of spleen and inguinal lymphadenopathy size, ecotropic virus titres in the spleen, or in vitro proliferative responses to mitogen. Th2 cytokine production was not enhanced in co-infected animals, except for an isolated increase in IL-4 production 21 weeks after LP-BM5 infection. Co-infected animals had significantly lower lymph node and spleen weights than mice infected with LP-BM5 only. MAIDS did not influence the granulomatous response to S. mansoni in the liver of co-infected mice. Finally, infection with S. mansoni neither enhanced Th2 cytokine production nor accelerated MAIDS progression in animals subsequently challenged with LP-BM5.

Genotypic-phenotypic variations in a series of 65 patients with familial amyloid polyneuropathy

OBJECTIVE

To investigate the genotypic-phenotypic variations in a series of patients with familial amyloid polyneuropathy (FAP).

BACKGROUND

Progress in molecular genetics has led to the identification of point mutations in the transthyretin (TTR) gene in FAP--a dominantly inherited neuropathy with a fatal outcome. These findings have modified the management of patients with small-fiber neuropathy and allow genetic counseling.

METHODS

We performed a clinical and molecular genetic study with screening of the TTR gene mutations and associated haplotypes in 65 patients from 29 unrelated families of French ancestry.

RESULTS

We detected nine heterozygous point mutations segregating with FAP. Fourteen families (48%) carried the common methionine (Met) 30 substitution. Seven kindreds (24%) had previously unreported TTR variants, namely asparagine 35, serine (Ser) 91, phenylalanine (Phe) 77, and Ser 116. At least two different haplotypes were associated with each of the following: Met 30, Phe 77, and valine 107, suggesting that multiple founders occurred for each variant. Only 35% of the index patients had affected relatives. Other patients had a sporadic presentation. All progressed to a severe sensorimotor and autonomic neuropathy with frequent cardiac involvement (80%). On average, a late age at onset (54.3 +/- 13.3 years) and a disease duration shorter than 10 years were observed for virtually all variants.

CONCLUSION

The heterogeneity of the TTR variants, the late age at onset, and the short duration of the disease found in our patients contrast with the presentation of FAP in Portugal. These findings must be taken into account in the management of both patients and asymptomatic carriers.

[Isolated intramedullary cysticercosis. Case report]

BACKGROUND AND PURPOSE

Cysticercosis is the most common parasitic disease affecting the central nervous system. Although it is still very rare in Europe, the frequency will increase due to the influx of immigrants from the endemic areas and increasing trips in these countries. Spinal intramedullary cysticercosis is an uncommon manifestation of neurocysticercosis.

CLINICAL PRESENTATION

We report a case of pure intramedullary cysticercosis in a young white French girl, presenting as a progressive paraplegia with a cystic lesion in T4 on MRI. The diagnosis was made only after surgery by pathological examination.

CONCLUSIONS

A preoperative diagnosis of spinal intramedullary cysticercosis must be suspected not only in an endemic area in the presence of multiple soft tissue calcifications and segmental lesions revealed by myelography or MRI studies, but also for all cystic lesion of central nervous system even in no endemic area. Surgery is the unique treatment which can be used for spinal intramedullary cysticercosis and with the use of the microsurgical techniques for medullar surgery the outcome is not as dismal as reported earlier.

MRI-neuropathological correlations in type 1 lissencephaly

Although imperfect, MRI is the best way of distinguishing type 1 lissencephaly from other, less classical lissencephalic malformations. We reported a case in which correlation of MRI and neuropathology was possible. Besides the classical radiological features of lissencephaly, i.e., agyria and excessive thickness of the cortex, an additional sign was observed: a thin cortical band, which gave high signal on T2-weighted images, represented a paucicellular and partially myelinated band, 1500 microns thick, lying under the true superficial cortex. This MRI feature could be characteristic of the particular cortical lamination observed in true type 1 lissencephaly.

Activity of fotemustine in medulloblastoma and malignant glioma xenografts in relation to O6-alkylguanine-DNA alkyltransferase and alkylpurine-DNA N-glycosylase activity

Fotemustine is a chloroethylnitrosourea with antitumor activity in disseminated melanoma and adult primary brain tumors. Because new drugs are required for the treatment of medulloblastoma in children, we evaluated the preclinical antitumor activity of fotemustine in four s.c. medulloblastoma xenografts, in comparison with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Both drugs were administered as a single i.p. injection to nude mice bearing advanced-stage tumor. Fotemustine displayed significant antitumor activity in three of four medulloblastoma xenografts; two, IGRM34 and IGRM57, were highly sensitive, with 37 and 100% tumor-free survivors, respectively, more than 120 days after treatment at the highest nontoxic dose (50 mg/kg). Fotemustine was also highly active in a malignant glioma xenograft (IGRG88; five of six tumor-free survivors on day 177). Fotemustine proved to be significantly more active than BCNU in IGRM34 and the glioma xenograft IGRG88. The DNA repair protein O6-alkylguanine-DNA alkyltransferase (ATase) was detected in all tumor xenografts, ranging in activity from 6 to 892 fmol/mg protein. The high in vivo sensitivity to fotemustine and BCNU observed in three xenografts was clearly associated with a low ATase activity (> 20 fmol/mg), whereas the two poorly sensitive or refractory medulloblastoma xenografts showed high ATase activity (> 500 fmol/mg). Alkylpurine-DNA N-glycosylase activity was detected in all tumor xenografts but at levels ranging only from 513 to 1105 fmol/mg/h; no consistent relationship was found between alkylpurine-DNA N-glycosylase activity and the in vivo sensitivity to the two chloroethylnitrosoureas. The improved activity and tolerance of fotemustine in comparison with BCNU in pediatric medulloblastoma xenografts strongly support the clinical development of this agent in children with brain tumors, in which ATase should be examined as a potential prognostic indicator.

Immunodot detection of nisin Z in milk and whey using enhanced chemiluminescence

A highly specific antisera was produced in New Zealand white rabbits against nisin Z, a 3400 Da bacteriocin produced by Lactococcus lactis ssp. lactis biovar. diacetylactis UL 719. A dot immunoblot assay was then developed to detect nisin Z in milk and whey. As few as 1.5 10(-1) international units per ml (IU ml-1), corresponding to 0.003 microgram ml-1 of pure nisin Z, were detected in carbonate-bicarbonate buffer within 6 h using chemiluminescence. When milk and whey samples were tested, approximately 0.155 microgram ml-1 (7.9 IU ml-1) of nisin Z was detected. The detection limit obtained was lower than that of traditional methods including microtitration and agar diffusion.

Cryptococcus neoformans infection in mice previously infected with LP-BM5 MuLV, the agent of murine AIDS (MAIDS)

We studied susceptibility to experimental systemic cryptococcosis in mice previously infected with the retroviral complex LP-BM5 (responsible for murine AIDS). LP-BM5 was inoculated to C57B1/6 mice by intravenous (i.v.) injection 8 weeks before an i.v. challenge with 4 x 10(3) CFU of Cryptococcus neoformans. Uninfected and singly infected mice were used as controls. LP-BM5 infection did not result in a significant increase in fungal burdens in the lungs or brains of co-infected animals compared to mice infected with C. neoformans alone. However, mortality was enhanced in the co-infected animals. The kinetics of splenocyte subsets differed in co-infected mice and LP-BM5-infected mice; the increase in CD4+, CD8+ and Ly5+ cells was only moderate in the former. Cytokine production by concanavalin A (Con A)-stimulated splenocytes from co-infected mice showed a marked decrease in the Th1 response (IFN-gamma, IL-2) and an increase in the Th2 response (IL-4, IL-10). Furthermore, cryptococcosis altered the course of MAIDS, inhibiting splenomegaly. This effect was not related to a decrease in ecotropic virus titres in the spleen or to improved in vitro responsiveness of spleen cells to Con A. The marked decrease in IFN-gamma production in co-infected animals could partly explain the inhibition of LP-BM5-induced splenomegaly. This model of murine retroviral infection does not seem to be suitable for studying cryptococcosis in immunosuppressed animals, but remains valuable for investigating in vivo interactions between two pathogens.

Paraganglioma of the cauda equina: MR findings. One case

Paraganglioma of the filum terminale is a rare tumor but well described in the neurosurgery and pathology literature. Few MRI reports are mentioned. Paraganglioma, often misdiagnosed with ependymoma or schwannoma on MRI images, must be kept in mind, when a highly vascular lesion with serpentine vessels is observed.

Note: genetic and biochemical characterization on nisin Z produced by Lactococcus lactis ssp. lactis biovar. diacetylactis UL 719

The bacteriocin produced by Lactococcus lactis ssp. lactis biovar. diacetylactis UL 719 was purified and characterized. Two peaks exhibiting antimicrobial activity were obtained after purification. Primary structure of the peptide of major peak 2 was identical to that of nisin Z when determined by Edman degradation and confirmed by DNA sequence analysis. The molecular mass as determined by mass spectrometry was 3346.39 +/- 0.40 Da for peak 1 and 3330.39 +/- 0.27 Da for peak 2, which suggests that peak 1 may correspond to an oxidized form of nisin Z. The two purified peaks exhibiting antimicrobial activity appear to correspond with oxidized and native forms of nisin Z.

Purification and structure of mutacin B-Ny266: a new lantibiotic produced by Streptococcus mutans

Mutacins are bactericidal substances of proteinaceous nature produced by Streptococcus mutans. Lantibiotics are antibacterial substances containing post-translationally modified amino acids such as lanthionine. Mutacin B-Ny266 was purified from the cell pellet of S. mutans strain Ny266 by ethanol extraction at pH 2.0 followed by reversed-phase chromatography (Sep-Pak cartridge) and by HPLC on a C18 column. The mean purification factor was 3240 +/- 81 and the mean yield was 1.0 +/- 0.1%. Molecular mass of mutacin B-Ny266 as determined by mass spectroscopy is 2270.29 +/- 0.21 Da. The amino acid sequence of the purified active fraction was obtained by Edman degradation after treatment with alkaline ethanethiol. Twenty-one amino acids were detected in this analysis. Mutacin B-Ny266 belongs to the type A lantibiotics. The proposed sequence is: F-K-A-W-U-F-A-Abu-P-G-A-A-K-O-G-A-F-N-U-Y-A. The molecule differs from that of epidermin/staphylococcin 1580 and gallidermin at positions 1, 2, 4, 5 and 6.

Painful proximal diabetic neuropathy: inflammatory nerve lesions and spontaneous favorable outcome

Proximal diabetic neuropathy is a disabling neuropathy that occurs predominantly in non-insulin-dependent diabetic patients over the age of 50. Inflammatory lesions have been found in nerve biopsy specimens of diabetic patients with severe proximal neuropathy or with other patterns of multifocal neuropathy. Some of these patients respond dramatically to treatment with corticosteroids or with other immunomodulators. In this article we report on our findings in 4 additional patients with painful proximal diabetic neuropathy and different patterns of inflammatory nerve lesions whose condition improved spontaneously shortly after performance of a nerve biopsy, without additional treatment.

Microbial dynamics of co- and separately entrapped mixed cultures of mesophilic lactic acid bacteria during the continuous prefermentation of milk

Four strains of mesophilic lactic acid bacteria were separately or coentrapped in kappa-carrageenan/locust bean gum gel beads and used for continuous prefermentation of UHT skim milk in a stirred-tank bioreactor. Lactic acid and cell productivities of the immobilized cell bioreactor were particularly high and remarkably stable during eight weeks of continuous milk prefermentation (about 18 g h-1 l-1 of lactic acid and 4.9 x 10(12) CFU h-1 l-1, respectively, but important variations of the bacterial populations is prefermented milk and gel beads occurred in any case (co-or separate entrapment). The strain Lactococcus lactis subsp. lactis biovar diacetylactis CDII became dominant, accounting for approx. 90% (released cells) and 78% (immobilized cells) of the total population. Microscopic observations of sections of gels beads showed a progressive destructing of the bead surface with rupture and release of entrapped viable cells from peripheral cavities of the gel. It is believed that these cavities close again after releasing all or part of their cell content, entrapping the different strains of the mixed culture and initiating a new colonization step and a cross-contamination of the beads. On the other hand, experimentations over seven-week periods with pasteurized milk showed the high resistance of the immobilized cell bioreactor to psychrotrophic contamination.

Use of an immobilized cell bioreactor for the continuous inoculation of milk in fresh cheese manufacturing

A system was developed to continuously acidify and inoculate skim milk for the production of fresh cheese. Four strains of mesophilic lactic acid bacteria were entrapped separately in kappa-carrageenan/locust bean gum gel beads and used in a stirred bioreactor operated at 26 degrees C with a 25% (v/v) gel load. The pH in the reactor was controlled at 6.0 by adding fresh milk using proportional integrated derived regulation. The bioreactor was operated during 8-h daily cycles for up to 7 weeks with different milks (heat treatment, dry matter content) and differing starting procedures. The heat treatment of the milk was an important factor for process performance: a dilution rate increase of 57% and an inoculation level decrease of 63% were observed with sterilized UHT skim milk (142 degrees C - 7.5 s) compared with pasteurized skim milk (72 degrees C - 15 s). The dry matter content of the milk (8-13% w/w) had no detectable effect on these parameters. A convenient starting procedure of the system was tested; steady-state was reached in less than 40 min following an interruption period of 16-60 h. These results combined with our published data on process performance show the feasibility of using an integrated immobilized cell bioreactor for milk prefermentation in cheese manufacture.

Effects of nifedipine and diltiazem on pharmacokinetics of cefpodoxime following its oral administration

We compared the effects of nifedipine and diltiazem on the uptake of cefpodoxime proxetil (CP). The study was aimed at establishing the impact of increased mesenteric blood flow due to calcium channel blockers on passive transport. Twelve volunteers were given CP (200 mg) orally in a crossover design. The absorption, disposition, and elimination parameters of cefpodoxime were compared among the following three treatment groups: CP alone, CP following oral administration of diltiazem (60 mg), or CP following oral administration of nifedipine (20 mg). No statistically significant difference in pharmacokinetic parameters was observed between the three treatment groups.

Contribution of nerve biopsy findings to the diagnosis of disabling neuropathy in the elderly. A retrospective review of 100 consecutive patients

Peripheral neuropathy is an important factor of disability in the elderly. In order to learn more on the usefulness of intensive evaluation of patients over 65 years of age with subacute or chronic disabling peripheral neuropathy, we reviewed the clinical and nerve biopsy findings of the last 100 patients of this age group who suffered from a peripheral neuropathy severe enough to justify performance of a nerve biopsy for a diagnostic or prognostic purpose. Normal nerve biopsy findings led to the diagnosis of lower motor neuron disease in three patients and pointed to lesions of the spinal roots in six other patients. Necrotizing arteritis was demonstrated in the biopsy specimens of 23 patients, and non-necrotizing vasculitis in five. In five additional patients the diagnosis of vasculitic neuropathy was kept in spite of non-contributive biopsy findings. In two diabetic patients who had a multifocal neuropathy the biopsy also revealed the presence of vasculitis. Thus 35% of the patients included in this series had one form or another of vasculitic neuropathy. Fourteen patients had a chronic inflammatory demyelinating polyneuropathy. In 11 patients the neuropathy was associated with monoclonal gammopathy, which was benign in nine and associated with malignant plasma cell dyscrasia in two. Among the six patients with diabetes mellitus, two patients who presented with a multifocal neuropathy were found to have vasculitis in the nerve specimen; in the others the biopsy was performed because of uncommonly severe pains or motor involvement due to an extremely severe diabetic neuropathy. Six patients suffered from a long-lasting disability secondary to a drug-induced neuropathy. The remaining 15% had neuropathies of different origin, including amyloidosis, lepromatous leprosy, carcinomatous neuropathy and alcoholic neuropathy. Six patients had a mild, non-progressive or slowly progressive axonopathy of unknown origin, ageing of the peripheral nervous system may have played a role in its development. Our findings show that vasculitis is an important and treatable cause of disabling neuropathy in the elderly and that the proportion of patients with severe neuropathy of unknown origin is small.

Pediocin 5 production and plasmid stability during continuous free and immobilized cell cultures of Pediococcus acidilactici UL5

Continuous production of pediocin 5 from Pediococcus acidilactici UL5 was investigated in MRS medium at different pH and dilution rates during continuous free cell (FC) and immobilized cell (IC) fermentations. Pediocin 5 activity from FC operated at a dilution rate of 0.31 h-1 largely increased from 128 to 2048 AU mL-1 as pH decreased from 7.0 to 5.0. Pediocin 5 activity in IC at a dilution rate of 0.93 h-1 was much less affected by pH, varying from 256 AU mL-1 at pH 7.0 to 512 AU mL-1 at pH 5.0. At the optimum pH 5.0, the dilution rate greatly influenced pediocin 5 activity both in FC and IC. Pediocin 5 production during continuous FC culture decreased with time for all dilution rates tested except 0.31 h-1 and average activity over 144 h cultures reached a maximal value of 4915 AU mL-1 at a dilution rate of 0.26 h-1. For IC, pediocin 5 production was stable with time and increased with the dilution rate from 256 to 1024 AU mL-1 in the range of 0.47-2.28 h-1. Three Listeria strains were tested for their ability to screen low bacteriocin-producing variants (Bac+v) of Bac+ cells in FC and IC cultures by using a modified deferred antagonism method. Ten to 28% of Bac+v cells appeared after 144 h of FC cultures at dilution rates in the range 0.09-0.42 h-1 and pH control set points of 5.0-7.0 while almost no Bac+v cell was detected during 192 h IC culture in the same pH range and for dilution rates varying from 0.47 to 2.28 h-1. The Bac+v cells isolated produced eight- to 64-fold less pediocin 5 than the Bac+ cells. Although electrophoresis analysis showed no apparent difference in the plasmid profiles of Bac+v and Bac+ cells, the Bac- mutant obtained by acriflavine treatment had lost the pMJ5 plasmid encoding for bacteriocin production. The decreased quantity of plasmid DNA in Bac+v cells suggests that the decreased pediocin 5 activity of Bac+v cells resulted from a decrease in plasmid copy number.

Extensive brain calcifications, leukodystrophy, and formation of parenchymal cysts: a new progressive disorder due to diffuse cerebral microangiopathy

A new cerebral disorder, described in three unrelated children, has recognizable clinical, radiologic, and neuropathologic findings. The onset occurs from early infancy to adolescence with slowing of cognitive performance, rare convulsive seizures, and a mixture of extrapyramidal, cerebellar, and pyramidal signs. CT shows progressive calcifications in the basal and cerebellar gray nuclei and the central white matter. MRI reveals diffuse abnormal signals of the white matter on T2-weighted sequences. A special feature is the development of parenchymal cysts in the cerebellum and the supratentorial compartment, leading to compressive complications and surgical considerations. Neuropathologic examination of surgically removed pericystic samples reveals angiomatous-like rearrangements of the microvessels, together with degenerative secondary changes of other cellular elements. Both the anatomic findings and the course of the disease suggest a constitutional, diffuse cerebral microangiopathy resulting in microcystic, then macrocystic, parenchymal degeneration.

Simple high-performance liquid chromatographic method for the quantitation of 5-fluorouracil in human plasma

A simple, rapid, specific and sensitive high-performance liquid chromatography method has been developed for quantitation of 5-fluorouracil (5-FU) in human plasma. The method involves deproteinization of a small sample volume of plasma (150 microliters) followed by HPLC on a cation-exchange resin column, Aminex HPX-87H (300 x 7.8 mm I.D.), preceded by a similar guard cartridge with UV detection at 265 nm. This method allows a good separation of 5-FU with a retention time of 24 min and a detection limit at 25 ng/ml. The calibration curve was linear from 25 to 2000 ng/ml. The coefficient of variation was < or = 4.4% for within-day reproducibility and < or = 9.5% for day-to-day reproducibility.

Increased serum levels of neuron-specific enolase in epileptic patients and after electroconvulsive therapy--a preliminary report

Serum neuron-specific enolase (NSE) levels were studied by an enzymo-immunoassay method in 2 groups of patients: a group of epileptic patients, and a group of patients with refractory major depression after electroconvulsive therapy (ECT). In patients without organic neurological disease (n = 274) the mean serum NSE level (+/- S.D.) was 8.4 +/- 3.4 micrograms/l. No correlation with sex or age was observed. No significant difference was observed between epileptic patients without seizure or major electroencephalogram (EEG) abnormality, and a reference group. Significant increases were observed in 32 samples collected from patients with interictal EEG without spikes and waves before the 7th day after a seizure, in whom mean NSE was 21.5 +/- 9.4 micrograms/l, and in 26 samples from 4 patients without seizures but with spikes and waves in the interictal EEG, whose mean NSE was 20.6 +/- 11.5 micrograms/l. The increases of serum NSE levels in epileptic patients seem therefore to be linked to seizures and/or to EEG abnormalities. The consequences of these observations for the survey of epileptic patients, and for the diagnosis of cerebral tumors (mainly neuroblastoma) or for monitoring treatment after surgical resection, are discussed. In only 1 patient out of 6, an increase in serum NSE levels was observed with a peak about 12 h after ECT. No significant correlation with the ECT features (length of seizures, one- or two-sided electrodes) was observed.

Identification of new enzyme activities of several strains of Thermus species

New thermostable enzyme activities of seven Thermus strains were compared using the API ZYM system. All the strains exhibited high levels of alpha- and beta-glycosidases, esterase (C4) and esterase-lipase (C8) activities intracellularly. Only T. thermophilus HB8 (ATCC 27634) showed alpha-glucosidase and esterase activities in the supernatant. According to the intensity of beta-galactosidase activity, Thermus strains were divided in three groups. Group 0, which showed a weak beta-galactosidase activity, included Thermus spp. ATCC 31674 (T351) and 27978 (X-1) as well as T. thermophilus ATCC 27634 (HB8). Group I which consisted of T. aquaticus ATCC 25104 (YT-1), ATCC 25105 (Y-VII-51B) and Thermus sp. ATCC 27737 (T2), had a specific activity of approximately 40.0 U mg-1 and galactose as inducer. T. aquaticus ATCC 31558 (group 2) was particularly effective for beta-galactosidase production (2840 U) with a specific activity of 98 U mg-1. For each strain, galactose (0.5%) was a better inducer of beta-galactosidase production than lactose (1%). The detection of beta-galactosidase activity was dependent on the derivative chromogenic substrates used (naphthyl or nitrophenol coupled to sugar). Oligosaccharides were synthesized from cellobiose, lactulose, maltose or lactose as substrates at high temperature in some strains of Thermus.

Peripheral neuropathy with necrotizing vasculitis in rheumatoid arthritis. A clinicopathologic and prognostic study of thirty-two patients

OBJECTIVE

To examine the clinicopathologic features of the noncompressive neuropathies in rheumatoid arthritis (RA).

METHODS

We studied 32 patients with RA and peripheral neuropathy whose nerve and/or muscle biopsy specimens exhibited necrotizing vasculitis. Morphologic analysis of nerve specimens included light and electron microscopy studies and teased fiber preparation. Survival was evaluated, and the prognostic values of clinical, biologic, and pathologic features were assessed by Cox proportional hazards model. A prognostic assessment based on the significant variables was devised to estimate the probability of survival of any individual patient.

RESULTS

Epi- and/or perineurial vasculitis was observed with the same frequency in the 17 patients with sensory and motor deficit and the 15 patients with sensory neuropathies and was associated with axonal degeneration of an average of 77.7% of the nerve fibers. The mean followup was 7.2 years, and the overall survival rate at 5 years was 57%. A full prolonged remission of the vasculitis was observed in 53% of the patients; relapse occurred in 25%. The factors correlated with mortality, in decreasing order of significance, were clinical cutaneous vasculitis (P = 0.0003), neuropathy affecting 3 or 4 limbs (P = 0.03), and depressed level of C4 (P < 0.05). The prognostic assessment indicated a wide range of 5-year probabilities of survival, from < 1% to 93%.

CONCLUSION

Necrotizing vasculitis is responsible for the different patterns of noncompressive neuropathies in RA, including mononeuritis multiplex and distal symmetric sensory or sensorimotor neuropathy. Cutaneous vasculitis, multifocal neuropathy, and depressed C4 level were the 3 independent variables which best predicted mortality. We propose a prognostic assessment according to these variables, to stratify patients to receive more aggressive or less aggressive therapy.

[Experimental models of toxoplasmosis. Pharmacological applications]

Toxoplasma gondii is an ubiquitous protozoan parasite causing severe or life-threatening infections in immunocompromised patients and in congenitally infected infants. Animal models have been extensively used to describe the pathology of infection and to identify new effective drugs for the treatment of congenital infections, chrorioretinitis and toxoplasmic encephalitis. Although inherent differences between man and animal can reduce the relevance of data obtained experimentally, animal models have greatly improved our knowledge on the various aspects of toxoplasmosis. Toxoplasma infection can be easily obtained in most laboratory animals, with exception of rats which are partially resistant. According to the strain used, the resulting infection may be acute, subacute or chronic, and can be monitored either by the survival of animals, the histopathological examination of lesions or, preferably, by titration of parasites in infected tissues using subinoculation to mice or tissue culture. This latter method has proved particularly useful to describe the kinetics of infection in host tissues and to assess the efficacy of drugs, according to their pharmacokinetics and tissue distribution. The relevance of results obtained in animal models of congenital toxoplasmosis and of chrorioretinitis is more questionable, due to the marked differences between the mode of infection in humans and in animals. Experiments performed in primates provided valuable informations for the management of therapy of congenital toxoplasmosis but were of limited interest for ocular toxoplasmosis. The pathogeny of toxoplasmic encephalitis is still poorly understood, and no experimental model is fully satisfactory to produce focal encephalitic lesions as observed in immunocompromised humans. Acute infections with highly virulent strains induce disseminated infection with major pulmonary and brain involvement, and thus can be used to assess the efficacity of drugs in these tissues. Direct inoculation of tachyzoites into brain tissue can induce focal encephalitis but this model is of difficult use for large scale studies. Although cellular immunity is mainly responsible for the control of toxoplasmosis at the chronic stage, administration of immunosuppressive drugs does not usually result in focal brain reactivation; such reactivation can only be obtained using antibodies against CD8 and CD4 T lymphocytes or interferon gamma. Another experimental approach is the use of genetically immunodeficient animals: these models are of limited interest for pharmacological research since infection of nude or T depleted mice usually results in a dissemination of infection; however, using these models it could be clearly demonstrated that immunity plays a major adjunctive role in the control of acute infection. Concurrent infections between viruses and parasites is a common feature in immunocompromised patients and especially during AIDS.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of diacetin B, a bacteriocin from Lactococcus lactis subsp. lactis bv. diacetylactis UL720

Fourteen Lactococcus lactis strains showing inhibitory activity against Listeria innocua SICC 4202 were isolated from different French raw milks and raw milk cheeses and screened for bacteriocin production by the triple layer method under conditions that eliminate the effects of lactic acid and hydrogen peroxide. Three bacteriocinogenic strains (two Lactococcus lactis subsp. lactis bv. diacetylactis UL719 and UL720 and one Lactococcus lactis subsp. lactis UL730) were selected for their high capacity to inhibit the growth of various food pathogens, including Listeria monocytogenes, Staphylococcus aureus, and clostridial strains. The inhibitory compounds from these three strains are inactivated by selected proteases, indicating their protein nature. They retained their antibacterial activity after heat treatments of 100 degrees C for 60 min and 121 degrees C for 20 min, and in the pH range from 2 to 11. The bacteriocin diacetin B produced by strain UL720 has been purified by a pH-dependent adsorption-desorption procedure, followed by reverse-phase high performance liquid chromatography, with a yield of 1.25% of the original activity. Mass spectrometry analysis indicates that the pure peptide has a molecular mass of 4292.32 or 4490.28 Da, while amino acid sequencing allowed the identification of the primary structure of the bacteriocin composed of 37 amino acid residues. The structure of the peptide did not show similarity with other known bacteriocins from lactic acid bacteria.