[Clinical and neuropathological study of two brothers with Cockayne syndrome]

INTRODUCTION

Cockayne syndrome (CS) is a rare autosomal recessive disease which is characterized by physical and mental retardation, progressive neurological disfunction, photosensitivity and other cutaneous features. Usually they present ophthalmologic abnormalities as well as other heterogenous clinical, radiological and pathologic features as leucodistrophy and calcifications in central nervous system and segmental demyelination in peripheral nervous system.

CLINICAL CASES

Two brothers, sons of healthy unrelated parents, are presented. The first patient was referred at 8 months of age because of psychomotor retardation and the second one at 5 months old because of a cataract. At the age of 2 years both presented a complex clinical picture with photosensitivity, growth and mental retardation, peripheral neuropathy, neurosensorial deafness, and cerebral atrophy and calcifications in neuroimaging diagnosis tests. In the following years the older brother presented signs of renal failure, cataracts and retinopathy, and died at 9 years old because of a respiratory infection. The neuropathologic study showed a discrete neuronal loss and diffuse demyelination with calcium deposits in cerebral white matter and basal ganglia. Today the second patient is 8 years old and shows a clinical course similar to that of his brother.

CONCLUSIONS

Clinical, radiologic and pathologic features in our patients support the diagnosis of CS type II.

Both B and gammadelta TCR(+) lymphocytes regulate alphabeta TCR(+) lymphocytes involved in superantigen specific responses

Endogenous superantigens (SAg) presented by MHC class II IA molecules induce slow-evolving negative selection of alpha beta T cells. The role of both B and gamma delta T cells on the regulation of these SAg-specific alpha beta T cell responses was addressed in IA(b+)IE(b-) C57BL/6 mice bearing genetically induced B cell and gamma delta T cell deficiencies. B lymphocytes were required in the negative selection of Vbeta5(+)/Vbeta12(+) CD4(+) T cells. In contrast, gamma delta T cells positively stimulated the utilization of the same SAg-responsive alpha beta T cell subsets. These differences started in mature CD4(+) thymocytes and extended to naive T cell pools for B cell negative selection, and up to memory T cells for gamma deltaT cell influences. The levels of SAg-responsive T cells did not vary between C57BL/6 and double deficient (B cell and gamma delta T cell-deficient) congenic mice, implying that both B and gamma delta T cells acted through independent mechanisms.

Biological and mechanistic activities of xanthorrizol and 4-(1',5'-dimethylhex-4'-enyl)-2-methylphenol isolated from Iostephane heterophylla

Xanthorrizol (1) and 4-(1',5'-dimethylhex-4'-enyl)-2-methylphenol (2) were identified as the principal antimicrobial components of a CH(2)Cl(2)-MeOH (1:1) extract derived from Iostephane heterophylla. Compound 2 is a new natural product, but has been synthesized. Both compounds exhibited low level activity (MICs of 16-32 microg/mL) against methicillin-resistant staphylococci and vancomycin-resistant enterococci. They were either inactive or poorly active against Gram-negative bacteria and yeast. Mechanistic studies performed in Escherichia coli imp suggested nonspecific inhibition of DNA, RNA, and protein synthesis by both of these compounds. Compound 1 was tested in an in vivo model; it did not provide protection to mice infected with Staphylococcus aureus.

[Neuromuscular syndromes of the critically ill]

With the continuous improvement in the survival of critical patients, new neuromuscular syndromes are being described. The clinical finding is an acute-subacute onset of generalised weakness with difficulty in weaning the patient from the ventilator, due to polyneuropathy, myopathy, prolonged neuromuscular blockade or a combination of these disorders. Although having a multifactorial ethiopathology, the major risk factors in the development of these disorders are multiple organ failure and sepsis for polyneuropathy; corticosteroids and neuromuscular junction blocking agents (NMB) for myopathy; and NMB and renal and liver failure for prolonged neuromuscular blockade. No specific treatment exists, which is why--due to the high incidence of these syndromes and their poor prognosis, with a mortality rate higher than 50%--we should recognise, diagnose and avoid, where possible, the conditions that help the development of these disorders.

Parasite and vertebrate host genetic heterogeneity determine the outcome of infection by Schistosoma mansoni

Intraspecific variation in Schistosoma mansoni infection and modulation of its expression by vertebrate host genetics was studied by evaluation of some biological parameters of the infection in BALB/c and C57BL/6 mice infected with one Brazilian (BH) and two Venezuelan (YT and SM) laboratory strains of the parasite. Mice infected with 60 cercariae of each parasite strain were euthanized at 5, 6, 8, and 12 weeks. Parameters recorded included the number of adult worms recovered by portal perfusion (infectivity); the number of eggs in the feces, the intestine, and the liver; and the ability of the eggs to cross the intestine, expressed as a quotient of the number of eggs in the intestine versus the feces. Results showed that the parasite appeared to determine the infectivity, the sex ratio, the onset and timing of oviposition, the number of eggs produced, initial egg laying toward the liver, and the ability to cross the intestinal wall. In this sense the BH strain appeared to be the most efficient and the SM strain, the most delayed; the YT strain was intermediate, although closer to the SM strain. On the other hand, the host appeared to influence the susceptibility to infection, the fecundity, and the percentage of eggs distributed in the liver and in the intestine during the chronic stage. In this sense, although they have been shown to be less susceptible to infection than BALB/c mice, C57BL/6 mice permit more eggs to be produced and exhibit similar numbers of eggs in the intestine and the liver at certain time points. It appears from these results that parasite genetics is essential for the outcome of infection with S. mansoni, but some characteristics may be quantitatively modulated by host genetics.

Diterpenoids from Azorella yareta and their trichomonicidal activities

Diterpenoids with trichomonicidal activity were isolated from the aerial parts of Azorella yareta Hauman. One was 13beta-hydroxyazorellane, together with the known constituents mulinolic acid, mulin-11,13-dien-20-oic acid, azorellanol and 13alpha-hydroxyazorellane. Their structures were determined by spectroscopic and chemical methods.

Diterpenoids from Haplopappus rigidus

Fractionation of the aerial parts of Haplopappus rigidus Phil., directed by the brine shrimp lethality test (BST), has led to the isolation of two new diterpenoids, rigidusol and deacetylrigidusol. Their structures were established as 13-hydroxy-18-acetoxy-cis-cleroda-3,14-diene (8betaH, 10betaH, 19beta, 20alpha form) and 13,18-dihydroxy-cis-cleroda-3,14-diene (8betaH, 10betaH, 19beta, 20alpha form), respectively. Rigidusol exhibit moderate cytotoxic activity against human breast adenocarcinoma cell line MCF-7. Their structures were established by spectral data, in particular using 2D NMR spectroscopy (DEPT, DQF-COSY, HMQC and HMBC).

Nasopharyngeal carcinoma in childhood and adolescence: a single-institution experience with combined therapy

BACKGROUND

A high cure rate may be attained for locally advanced, undifferentiated nasopharyngeal carcinoma (NPC) in children, provided that a combined modality of treatment is employed. Both local and systemic therapies are necessary. Results at a single pediatric institution were analyzed.

METHODS

From November 1988 to December 1997, 16 consecutive patients were treated with NPC at the Hospital Garrahan in Buenos Aires, Argentina. The authors were able to evaluate 11 patients (9 boys and 2 girls); their median age was 12 (range, 8-14) years. Chemotherapy consisted of 3 courses, every 3 weeks, of 5-fluorouracil (500 mg/m(2)) plus bleomycin (15 mg/m(2)) daily for 4 days, with cisplatin (100 mg/m(2)) added the last day. External beam radiotherapy was delivered over a median of 52 (range, 45-63) days, to a median cumulative dose to the primary site of 55 (range, 50-61.2) grays (Gy). The median dose for the lower neck area was 45 (range, 45-55.8) Gy. All patients received radiotherapy to the primary site and to the initially involved lymphoid areas, with daily single doses of 1.8 Gy (5 of 7 days per week).

RESULTS

The main symptoms at onset were cervical mass (100%), epistaxis (54%), cephalalgia (36%), and trismus (36%). All cases were Stage IV (American Joint Committee on Cancer and International Union Against Cancer TNM system). Complete response was achieved in 45% of patients after initial chemotherapy. With a median follow-up of 63 (range, 23-119) months, disease free survival (with standard error [SE]) and overall survival estimates were 61% (16%) and 91% (9%), respectively, at 75 months. Acute toxicity due to therapy was tolerable. Chronic sinusitis (73%), hypothyroidism (73%), and mild (64%) or moderate (9%) neck fibrosis were detected at follow-up.

CONCLUSIONS

Although this series is small, the authors concluded that NPC patients have a good chance of survival in the setting described, in spite of locally advanced disease. Chemotherapy might be useful in preventing the development of systemic metastases.

[Host parasite relationship among 3 Schistosoma mansoni and 6 Biomphalaria glabrata strains from epidemic and no epidemic Venezuelan areas is studied]

Six lots of 18 B. glabrata from: La Victoria, Turmero, Cagua in Aragua state; Caserío El 25 in Carabobo state, Chabasquén in Portuguesa state and Humocaro Bajo in Lara state, were experimentally infected with miracidia of SM, C5 and C6 strains of Schistosoma mansoni (18 snails/Schistosoma mansoni strain). The averages of the intramolluscal period (IMP) obtained for the S. mansoni strains were very similar and comprised between 35.4 and 36.1 days. No significative statistical differences in the IMP were found according to the S. mansoni strain and the size of snails: < 7 mm and > 7 mm. However, significative statistical differences in the IMP were found, in relation to the B. glabrata strain and between the snails classified in two groups according to the S. mansoni dose (5 miracidia/snail and 10 miracidia/snail). The higher percentages of infection (PI) were found for the following parasite-snail combinations: C6-Cas. El 25 (80.7%), SM-La Victoria (73.1%) and C5-Cagua (62%). No significative statistical differences were found for the PI a) between the snail classified in two groups according to the size (< 7 mm and > 7 mm), b) in relation to the miracidium dosification (5 and 10 miracidia/snail and c) in accord to the S. mansoni strain. However, significative statistical differences were found for the PI obtained with different strains of the snail.

[Multiple sclerosis and epileptic seizures]

INTRODUCTION

Although epileptic seizures are uncommon in multiple sclerosis they are more prevalent than in the general population, which supports an aetiological relationship. Similarly in a considerable proportion of patients with multiple sclerosis and epileptic seizures, alterations in magnetic resonance and electroencephalogram studies which could be correlated with the clinical features of epilepsy were observed. Nevertheless, it is difficult to establish definite clinical characteristics in these patients since the underlying pathogenic mechanisms are poorly understood and there is great variability with regard to the type of seizure, point at which this occurs during the course of the disease, degree of recurrence and other aspects.

CLINICAL CASE

We report the clinical, electroencephalographical and neuroimaging findings of seven patients with multiple sclerosis who had epileptic seizures and those in whom there was no evidence of other potentially epileptogenic pathology. In two patients the epileptic seizures formed part of the first episode of their illness. One patient presented more than one type of epileptic seizure. These seizures were generalized in two cases, partial sensory and/or motor with secondary generalization in three, simple partial motor in one and partial complex in two. The epileptic seizures coincided with other clinical features of episodes in three cases and the electroencephalogram showed anomalies in five cases.

CONCLUSIONS

The findings observed were of a wide variety, as was found in other reported series. We point out certain correlations between the clinical data, magnetic resonance and electroencephalogram which may help to orientate the management of these patients.

Mulinane-type diterpenoids from Laretia acaulis

In addition to the known mulinolic acid and mulin-11, 13-dien-20-oic acid, 13-epimulinolic acid has been isolated from the aerial parts of Laretia acaulis (Cav.) Gill et Hook (Umbelliferae). Its structure was based on spectroscopic comparison with mulinolic acid and by chemical characterization.

Formation of enzymatically active, homotypic, and heterotypic tetramers of mouse mast cell tryptases. Dependence on a conserved Trp-rich domain on the surface

Mouse mast cell protease (mMCP) 6 and mMCP-7 are homologous tryptases stored in granules as macromolecular complexes with heparin and/or chondroitin sulfate E containing serglycin proteoglycans. When pro-mMCP-7 and pseudozymogen forms of this tryptase and mMCP-6 were separately expressed in insect cells, all three recombinant proteins were secreted into the conditioned medium as properly folded, enzymatically inactive 33-kDa monomers. However, when their propeptides were removed, mMCP-6 and mMCP-7 became enzymatically active and spontaneously assumed an approximately 150-kDa tetramer structure. Heparin was not required for this structural change. When incubated at 37 degrees C, recombinant mMCP-7 progressively lost its enzymatic activity in a time-dependent manner. Its N-linked glycans helped regulate the thermal stability of mMCP-7. However, the ability of this tryptase to form the enzymatically active tetramer was more dependent on a highly conserved Trp-rich domain on its surface. Although recombinant mMCP-6 and mMCP-7 preferred to form homotypic tetramers, these tryptases readily formed heterotypic tetramers in vitro. This latter finding indicates that the tetramer structural unit is a novel way the mast cell uses to assemble varied combinations of tryptases.

Feeding frequency and nutritional status of peridomestic populations of Triatoma infestans from Argentina

We studied the nutritional characteristics of peridomestic populations of Triatoma infestans from 25 habitats in an endemic area of Chagas disease in Argentina. The aim was to determine the feeding frequency, fresh weight of adults and older nymphs, and the gonotrophic status of females, in order to compare them with previous studies of domestic populations in the same region. The average infection rate of the bugs and blood meal origins were also determined in order to calculate the maximum risk for Trypanosoma cruzi transmission in these habitats. The number of bugs in each habitat correlated positively with the number of hosts. The estimated number of bites per night was strongly correlated with the total number of bugs collected from that habitat. The shortest biting interval (1.9 and 1.7 days) occurred in November and February, where 52-60% of insects suck blood each night. Adults and nymphs recently fed showed significantly higher fresh weight in November. There was no apparent correlation between the mean weights of adults or nymphs and the number of insects found within each habitat. Bloodmeal analysis showed that most of the bugs (87%) had fed from chicken, with human and dog scarcely represented and no bloodmeals identified from cat. However, human bloodmeals were only identified from chicken coops near the house (< 12 m). Almost all females (92-100%) captured during the spring months had been mated, whereas the proportion of mated females decreased significantly during summer (60-71%). The maximum risk (MR) average from these peridomestic habitats was 0.35 bites from infective bugs/night, tenfold lower than MR from domestic habitats. The good nutritional status of recently fed bugs, found in these chicken coops during all the hot season, suggest that active dispersal is unlikely to occur from peridomestic habitats.

[Risk markers in subjects with high loads of Ascaris lumbricoides in a rural community of the Cojedes State , Venezuela]

A total of 337 individuals from a rural community of Venezuela (Mapurite, Estado Cojedes) was studied. Stoll faecal examination was carried out and the total number of A. lumbricoides was recovered after the treatment of the individuals sampled with Pyrantel pamoate at a dose of 10 mg/kg body weight in children and 15 mg/kg in adults. A relationship between the high worm burden condition (individuals excreting more than 10,000 epg of A. lumbricoides) and the age of the hosts was found. Resulting with the major values of relative risk index (Rr) the 5-9 years old class (Rr = 3.2 t = 3.4). This relationship was not found between high worm burden condition (HWB) and the sex of the hosts. The following individuals have the the highest possibilities to become HWB: with blood group A (Rr = 3.05 t = 4.08), with haemoglobin type HbA HbS (Rr = 1.86 t = 2.13), individuals with the combinations A HbA HbF (Rr = 3.46 t = 2.31) and A HbA HbS (Rr = 3.11 t = 2.78). It was estimated that the selective treatment of the total HWB detected (72) with an effective product, determined a reduction of 95.4% of the environmental contamination with de eggs and 72.3% of the worm burden.

[The size polymorphism of the cercariae of a Venezuelan strain of Schistosoma mansoni]

By mean of the silver impregnation of a lot of 47 cercariae belonging to C5 venezuelan Schistosoma mansoni strain, a polymorphism of size was evidenced. The morph was conformed by the greatest cercariae (between 152.9 microns to 218.4 microns). This group was ever present in the population of cercariae in less percentage (29.8%). The length of the normal cercariae was comprised between 119 microns to 152 microns. This group was the dominant in the population: 70.2%. The comparison between the length of both lots of cercariae resulted with significative statistical differences (t = 5.5; P < 0.001). For the total studied cercariae the average of the length was X = 143.9 microns and for the wide X = 68.6 microns. It was found a positive significative correlation between the wide and the length of the cercariae r = 0.83 (P < 0.001).

[Osteoporosis in Mexican postmenopausal women. Magnitude of the problem. Multicenter study]

Incidencia of osteoporosis induced fractures increases with age; risk increases exponentially as bone mass decreases. Women are prone to osteoporosis 2 to 3 times more than men, due to lower "peak" bone mass and the accelerated loss that occurs after the menopause. The prevalence of osteoporosis in with Caucasian postmenopausal women varies from 16 to 30% depending upon the number of sites measured (lumbar spine/hip and/or forearm). The aim of this study was to estimate the prevalence of osteopenia and osteoporosis in pre and postmenopausal Mexican women in relation to men, and to that reported in Caucasia women. The study involved 4,821 apparently healthy subjects (without known risk factors for osteoporosis), 4,467 females and 354 males from 11 different centers of Mexican Republic, 20 to 90 years old, using DXA bone densitometry of lumbar spine and hip. Prevalence of osteoporosis in women is twice that in men (P < 0.001), and it increases with age, particularly after the menopause (P < 0.0001). Our study found a prevalence of osteoporosis of the lumbar spine and/or hip in apparently healthy postmenopausal Mexican women over 50 years of age of 16%, increasing to 20% in those women with or without risk factors who attended voluntarily or by suggestion of their physician to be studied. The prevalence values obtained seem to be lower than those reported for Caucasian women, 30%. We found a prevalence of osteoporosis of 16% and of osteopenia of 57% in women 50 years of age and older. We also found a higher prevalence of osteoporosis in women of the south east part of the county.

Development of myasthenia gravis after interferon alpha therapy

Interferon (IFN) alpha is now used in the treatment of some malignant diseases and chronic viral hepatitis. There have been several reports of development of autoantibodies and autoimmune diseases or the deterioration of preexisting disorders in patients under treatment. We enclose a case of myasthenia gravis (MG) which developed after six weeks of treatment as fluctuating bilateral ptosis, intermittent diplopia, and mild weakness of limb and neck muscles. A test dose of edrophonium chloride was administered, resulting in improved muscle strength. Elevated anti acetylcholine receptor (AChR) antibody titer was found. Single fiber electromyography showed an increased jitter from extensor digitorum communis, frequently accompanied by transmission blocking. Repetitive electric 3 Hz stimulation of the abductor pollicis brevis muscle, revealed an abnormal decrement of 28% in compound motor action potential. Myasthenia gravis was diagnosed and the patient was given pyridostigmine, immunoglobulines and prednisone with benefit. Six months latter he developed an acute myasthenic crisis with severe respiratory failure and high anti AChR antibody titer. IFN-alpha can induce MG or simply manifests a preexisting subclinical disease, but otherwise its therapeutic efficacy in MG has been shown in experimental and clinical studies. Autoimmune mechanisms, as the release of different cytokines as IFN, by immunocompetent cells, may be involved in the pathogenesis of both MG and chronic active hepatitis. Autoantibody production against postsynaptic membrane structures by IFN-alpha could be the underlying pathophysiology.

The expression of the Leishmania infantum KMP-11 protein is developmentally regulated and stage specific

Transcription of the gene coding for the KMP-11 protein of Leishmania infantum results in the production of a mature RNA transcript of 1.3 kb in length. The expression of KMP-11 mRNA is strongly down-regulated not only during the parasite growth from the logarithmic to the stationary phase but also during the differentiation transit from promastigotes to amastigotes. The estimated concentration of KMP-11 is one order of magnitude higher in promastigotes than in amastigotes. The analysis of the Triton X-114 phase partition of the protein shows that, in agreement with its predicted secondary structure, KMP-11 has an amphipathic nature since it is found in the aqueous as well as in the detergent phase. By fluorescence microscopy a defined pattern of distribution of the protein was observed only in promastigotes where KMP-11 is mainly located in the flagellum and the flagellar pocket.

[Relationships in the prevalence of geohelminth infections in humans from Venezuela]

By means of Kato-Katz technique 113,254 coprological samples of the human population belonging to 100 counties from Venezuela were analyzed. It was determined the following prevalences: Ascaris lumbricoides 26.8%, Trichuris trichiura 32.7% and hookworm 5.6%. It was found a strong correlation between A. lumbricoides and T. trichiura infection (p < 0.001), a significant correlation between T. trichiura and hookworm (p < 0.5) and no correlation between A. lumbricoides and hookworm.

[Familial benign partial epilepsy of early infancy]

INTRODUCTION AND CLINICAL CASES

We present two patients who at the ages of 5 and 17 months respectively presented with convulsive crises with motor signs, of partial onset and secondary generalization, which eventually became normal. Both patients had a family history of first degree relatives with similar illnesses and are at present-five years later-well and with normal development, school achievement and neurological examination findings. The clinical characteristics, normal biochemical and neuroimaging investigations and EEG characteristics suggest the diagnosis of benign partial epilepsy of early infancy. This syndrome is characterized by its appearance during the first year of life, having no known etiological factors, with partial crises occurring several times a day and with a course leading to remission. Its frequency may be greater than is thought. There is a pattern of dominant autosomal inheritance, with a gene recently found on chromosome 19.

CONCLUSION

We consider that this syndrome should be included in the International Classification of Epilepsy and Epileptic Syndromes as benign familial idiopathic partial epilepsy.

Outbreaks of trypanosomosis due to Trypanosoma vivax in cattle in Bolivia

This paper reports the first occurrence of bovine trypanosomosis due to Trypanosoma vivax in Bolivia. T. vivax was identified in thin blood smears of 159 cattle from the Provinces of Velaco (57), Nuflo de Chavez (20), Guayaros (30) and Chiquitos (52), and in 86.20% of 29 cattle from Laguna Concepción examined by microhematocrit test. The clinical signs observed were fever, anemia, abortion, progressive weakness, loss of appetite, lethargy, substantial weight loss in a relatively short time, and progressive emaciation.