Germination of Nosema algerae (Microspora) spores: conditional inhibition by D2O, ethanol and Hg2+ suggests dependence of water influxupon membrane hydration and specific transmembrane pathways

The germination of microsporidian spores under conditions expected to affect water flow across the plasma membrane-wall complex was studied by assessing their responses to in vitro stimulation with Na+ or K+. Partial or full substitution of common water with D2O, which more effectively coats ions and electrostatically-charged cell surfaces with relatively stable hydration layers, delayed and inhibited spore germination in a concentration-dependent manner; yet, preincubation in 100% D2O did not change the normal response to standard stimulation. Water structure-breaking conditions, such as an increase in temperature (within the 15 degrees C to 40 degrees C range) or in ionic strength (1- to 10-fold normal), opposed the inhibition by D2O and allowed significant stimulation by Li+, the monovalent cation with the largest hydration diameter and a usually weak stimulant action on the spores. Ethanol, known to reduce water permeation across cell membranes and phospholipid bilayers, also caused a powerful and dose-dependent (1% to 4% v/v) inhibition of spore germination, but pretreatment with ethanol did not affect the normal response. HgCl2, an inhibitor of specific water channels, blocked spore germination at just 250 microM in the normal stimulation solution irrespective of the temperature, and permitted only a delayed response in high salt stimulation solutions. However,the inhibition by Hg2+ was abolished by the simultaneous presence of 2-mercaptoethanol in the medium. These results suggest (1) that spore germination is keenly dependent upon the hydration states of both the plasma membrane-wall complex and the stimulant ions, and (2) that osmotic water flows into the spores through specific transmembrane pathways with critical sulfhydryl groups, i.e., analogous to the water channels that facilitate water movements across the plasma membranes of highly permeable cells.

Subcutaneous phaeohyphomycosis caused by Phoma cava. Report of a case and review of the literature

We report a case of subcutaneous phaeohyphomycosis observed in a male patient presenting pulmonary sarcoidosis and submitted to corticosteroid treatment. He presented nodular erythematous-violaceous skin lesions in the dorsum of the right hand. Histopathological examination of the biopsied lesion revealed dematiaceous hyphae and yeast-like cells, with a granulomatous tissual reaction. The isolated fungus was identified as Phoma cava. A review of the literature on fungal infection caused by different Phoma species, is presented. The patient healed after therapy with amphotericin B. followed by itraconazole.

Efficacy of triple combination therapy with zidovudine (ZDV) plus zalcitabine (ddC) plus lamivudine (3TC) versus double (ZDV+3TC) combination therapy in patients previously treated with ZDV+ddC

OBJECTIVE

To evaluate the immunological and virological efficacy of triple combination therapy with zidovudine (ZDV) plus zalcitabine (ddC) plus lamivudine (3TC) and a double (ZDV+3TC) combination therapy in patients previously treated with ZDV plus ddC.

DESIGN

A 6-month follow-up open-label randomized study was undertaken in 46 HIV-1-infected patients previously treated for at least 6 months with ZDV plus ddC, who were allocated to receive either ZDV/ddC/3TC (n = 15) or ZDV/3TC (n = 15) or to continue with the ZDV/ddC regimen (control group; n = 16).

METHODS

Changes in CD4+ cell counts and plasma viral load (VL) were analysed with analysis of variance. Sequencing of the reverse transcriptase gene was performed in a subset of 3TC-treated patients.

RESULTS

Mean CD4+ cell counts increased significantly above baseline in both 3TC regimens whereas counts decreased in the control group. Significant plasma VL reduction was achieved in both 3TC combination therapy groups at weeks 4 and 24 compared with the control group. Coexistence of mutations conferring resistance to ZDV and 3TC were found in patients from both 3TC treatment groups.

CONCLUSIONS

Both therapy strategies, switching ddC to 3TC or adding 3TC, significantly improved the virological and immunological efficacy compared with continuing ZDV/ddC. Our results support the use of 3TC in patients previously treated with the ZDV/ddC combination.

Plasma HIV-1 RNA as a predictor of the efficacy of adding zalcitabine to a previous regimen with zidovudine

The objective of this study was to determine whether or not plasma HIV-1 RNA levels, the syncytium-inducing phenotype assay or mutations at codon 215 of the gene encoding HIV-1 reverse transcriptase could have prognostic value in patients already undergoing therapy with zidovudine who were started on combination therapy with zidovudine and zalcitabine. A prospective study was performed in 37 HIV-1-infected individuals who had received at least 6 months (mean: 9 months; range: 6-24 months) of zidovudine to which zalcitabine was added. The mean initial CD4 cell count was 330 cells/mm3 (range: 20-520 cells/mm3). At baseline and at the end of the study (12 months), we analysed CD4 and CD8 cell counts, plasma HIV-1 RNA levels, the syncytium-inducing phenotype of virus isolated from peripheral blood mononuclear cells and mutations at codon 215 of the gene encoding reverse transcriptase. These variables were studied by Fisher's exact and U Mann-Whitney tests. There were statistically significant differences between progressor and non-progressor groups at baseline and after a 12-month period in the following parameters: CD4 and CD8 cell counts and HIV-1 RNA level (P < 0.05). Clinical progression occurred significantly more often in patients with CD4 cell counts < or = 300 cells/mm3 and HIV-1 RNA > 30000 copies/ml at baseline (P = 0.003). Moreover, we found that progression to AIDS only occurred in those patients whose viral load increased during the follow-up period and who had a CD4 cell count < 300 cells/mm3. Our results show the usefulness of HIV-1 RNA level as a surrogate marker for clinical outcome.

Quantitative HIV-1 RNA as a marker of clinical stability and survival in a cohort of 302 patients with a mean CD4 cell count of 300 x 10(6)/l

OBJECTIVE

To analyse plasma HIV-1 RNA levels as a marker of clinical stability and survival in a cohort of HIV-infected patients whose time of seroconversion is unknown.

DESIGN

Retrospective cohort study.

SETTING

Retrovirology laboratory and AIDS Unit in a teaching hospital.

PATIENTS

A total of 916 samples from 302 patients, most on antiretroviral therapy, were analysed. Mean initial CD4 cell counts and HIV-1 RNA were 299 x 10(6)/l (range: 0-1600) and 134,261 copies/ml (range: < 200-4,300,000), respectively. Sixty-six cases had been diagnosed previously with AIDS.

METHODS

Analysis of progression to AIDS and survival, according to initial and longitudinal viral load (VL) and CD4 cell count measurements was performed by Kaplan-Meier test. Relative risks were calculated by Cox's proportional hazards model.

RESULTS

During a mean follow-up of 444 +/- 309 days, 29 patients developed AIDS and 21 died. Relative risk (RR) of progression related to the group with VL < 35,000 was: 10.4 when CD4 > or = 250 x 10(6)/l and VL > or = 35,000 (P = 0.001); and 45.3 when CD4 < 250 x 10(6)/l and VL > or = 35,000 (P < 0.0001). Cumulative probability of progression was: 0%, 0% and 12.3%, at the first, second and third year respectively, for patients with all their sequential VL determinations < 60,000; and 13.3%, 34.7% and 79.3% for patients who did not maintain VL values always < 60,000 (RR = 23; P < 0.0001). The minimum value of VL that reached statistical significance for the survival analysis was 100,000 copies/ml (P < 0.0001).

CONCLUSIONS

VL > or = or < 35,000 is a better discriminant for progression than a CD4 cell count > or = or < 250 x 10(6)/l. Sequential VL determinations < 60,000 are associated with a better prognosis.

Short-term anti-HIV activity of the combination of didanosine and hydroxyurea

The synergistic action of hydroxyurea with some other antiretroviral drugs led us to evaluate the effect of therapy with the combination of didanosine and hydroxyurea in HIV-1-infected patients. We aimed to assess the anti-HIV activity of therapy with this combination by measuring variations in viral load and in CD4 cell counts. We also evaluated the potential side effects of this drug combination in HIV-1-positive patients with advanced disease. A total of 15 HIV-1-seropositive homosexual men with a mean baseline CD4 cell count of 149 cells/mm3 (range: 1-430 cells/mm3) were recruited to the study, and received didanosine (200 mg) plus hydroxyurea (500 mg) twice daily for 12 weeks. Ten patients were didanosine naive and five had previously received didanosine (for > 3 months). The combination therapy was well tolerated, although grade 2-3 alopecia appeared in four patients who had very low CD4 cell counts (< 50 cells/mm3). No significant variation in renal, hepatic and pancreatic functions occurred. A significant reduction in the plasma HIV-1 RNA (> 0.5 logs) was observed in seven of ten patients naive to didanosine after weeks 4 and 12 of the study; five of these patients had a decrease in plasma HIV-1 RNA of > 1.5 logs, with two having a decrease of > 2.0 logs. The viral load became undetectable (below 200 copies/ml) in three patients. The patients whose plasma HIV-1 RNA levels were not significantly reduced by the combination therapy had a higher baseline viral load. CD4 cell counts did not increase significantly in most patients. We observed a better response in those patients who had virus of the non-syncytium-inducing phenotype. In conclusion, hydroxyurea in combination with didanosine was well tolerated and led to a reduction in viral load mainly in patients who were initially naive to didanosine.

Resistance-related mutations in the HIV-1 protease gene of patients treated for 1 year with the protease inhibitor ritonavir (ABT-538)

OBJECTIVE

To define genotypic and phenotypic resistance patterns following prolonged therapy with the protease inhibitor ritonavir (ABT-538).

DESIGN

Seven HIV-1-infected patients, all but one previously treated with dideoxynucleoside analogues (zidovudine, didanosine, zalcitabine), were treated for 1 year with ritonavir.

METHODS

Direct solid-phase sequencing of the protease gene starting from plasma derived viral RNA followed by comparison to phenotypic drug resistance data.

RESULTS

The most frequent amino-acid substitutions occurring upon administration of the protease inhibitor were V82A/F (substrate binding site), I54V (flap region), A71V and L10I. Additional mutations found in more than one patient were I15V, M36I, I84V and I93L. Mutation L63P was found both in pre- and post-ritonavir samples. Phenotypic drug resistance assays confirmed resistance to ritonavir in post-treatment samples (approximately 170-fold) and showed cross-resistance to indinavir (approximately 30-fold) and partially to saquinavir (approximately fivefold). At 1 year of treatment, one patient without known resistance-associated mutations in the protease gene still showed a substantial rise in CD4 cell count accompanied by a more than 2.4 log decrease in RNA viral load. However, at week 78, mutations R8Q, E34K, R57K, L63P and I84V were detected and the treatment benefit was partially lost.

CONCLUSIONS

Long-term treatment with ritonavir is associated with the emergence of multiple mutations in the HIV-1 protease gene. The mutations L10I, I54V, L63P, A71V, V82A/F and I84V correspond to known drug-resistance mutations for ritonavir and other protease inhibitors. Phenotypic resistance to ritonavir was detected in a majority of ritonavir-treated patients at 1 year of treatment. In addition, long-term ritonavir treatment selects for cross-resistance to the protease inhibitors indinavir and saquinavir. This argues against sequential therapy with several protease inhibitors. Delayed resistance in one patient was accompanied with a prolonged increase in CD4 cell count and decrease in viral load suggesting a temporary benefit of treatment.

Do intestinal parasites interfere with the seroepidemiologic surveillance of Schistosoma mansoni infection?

In view of the known cross-reactivity of sera from patients with intestinal parasites to some Schistosoma mansoni antigens, field work was conducted in an area of Venezuela non-endemic for schistosomiasis using the routine immunoenzymatic assay (ELISA) with soluble egg antigen (SEA). False positive reactions represented 15.3% of the total population as determined by SEA-ELISA. SEA-immunoblotting of the false positive sera indicated that protein fractions of 91 and 80 kDa appear to be responsible for cross-reactivity. Sera from hookworm infected individuals produced a higher frequency and intensity of cross-reaction than other sera. SEA-fractions of 105, 54, 46, 42, 32, 25 and 15 kDa were the most specific.

A record card for the study of Neuronal Hyperexcitability Syndrome

Neuronal Hyperexcitability Syndrome (NHS) is a nosographic picture which is difficult to diagnose, due to the lack of specific standard diagnostic criteria. With slightly varying symptoms the syndrome has also been defined as Spasmophilia and Hyperventilation Syndrome. It is difficult to distinguish between NHS and panic attack disorder as there is considerable overlapping of symptomatology. We aimed to propose a standardized card which will be the first step toward a valid diagnosis of this complex neuropsychiatric problem. This card, which will be validated and of which the reliability will be evaluated, is proposed for clinical and research purposes. The card is made up of 6 parts (113 items) covering: personal data, pharmacological treatment, persistent diseases and related therapies, symptomatology trend, factors interfering with calcium-magnesium homeostasis and symptom assessment. The symptom assessment section is essential for the checking of diagnostic criteria and the earlier sections are important for the monitoring of other factors which can cause symptoms able to simulate NHS. There are also two special sections for recording laboratory tests and patients' psychic profiles.

Spatial control of neuronal cell attachment and differentiation on covalently patterned laminin oligopeptide substrates

The spatial control of neuronal cell attachment and differentiation via specific receptor mediated interactions, may provide an effective means for the in vitro reconstruction of neuronal cell architecture. In this study, receptor-specific oligopeptide sequences derived from the extracellular matrix (ECM) molecule laminin, a potent neural cell attachment and differentiation promoter were covalently bound on fluorinated ethylene propylene (FEP) films. The degree of receptor-specific cell attachment and the ability to spatially control neurite outgrowth by covalently patterning the oligopeptide sequences on the FEP film surface were assessed. FEP films were first chemically activated with a Radio Frequency Glow Discharge (RFGD) process that covalently replaces the surface fluorine atoms with reactive hydroxyl groups. Oligopeptides containing the YIGSR sequence from the B1 chain of laminin and the water soluble oligopeptide containing the IKVAV sequence (CSRARKQAASIKVAVSADR) from the A chain were covalently bound to the hydroxylated FEP films. Electron Spectroscopy for Chemical Analysis (ESCA) verified the covalent attachment of the oligopeptides to the material surface. The degree of receptor mediated NG108-15 cell attachment on immobilized CDPGYIGSR films was determined using competitive binding media. A 78% reduction in cell attachment was observed on films containing CDPGYIGSR in the cell plating medium. Only a 23% reduction in cell attachment was noted on films plated in medium containing a mock CDPGYIGSK sequence. FEP films immobilized with the IKVAV oligopeptide sequence were shown to mediate PC12 cell attachment and a competitive binding medium also significantly attenuated cell attachment on the immobilized films. The spatial patterning of these oligopeptide sequences to the FEP surface was shown to localize cell attachment and neurite extension on the patterned pathways. The surrounding unmodified FEP surface was inhibitory in serum containing medium and prevented cellular interactions outside the oligopeptide modifications. The spatial immobilization of laminin oligopeptides on FEP films provides a means to organize the attachment and differentiation of neuronal cells in a receptor-specific manner.

[Imported acute hepatitis in Spanish travelers to tropical countries]

Among the immunizable diseases, viral hepatitis is the most frequently diagnosed in travellers. The epidemiology and the clinical presentation of the imported viral hepatitis among patients in the Tropical Medicine Unit of Hospital Clínic (Barcelona) are studied in this article. A retrospective review of 47 viral hepatitis in Spanish travellers seen during the period 1988-1991 is presented, representing 2.47% of all diagnosis. Only a third of the patients were hepatitis A cases. The duration of the trip was significantly shorter in those who acquired hepatitis of the A and non-A--non-B types. Africa (60% cases), India and South East Asia (17%) and Central America (16%) were considered areas of risk. The B, C and non-A--non-B hepatitis types had a more silent clinical and biological presentation. Gathered data confirm the importance of hepatitis as an imported disease, the partial protection of the Spanish population against hepatitis A and the need to introduce this infection among the advice to be given in a travellers clinic.

Elephantiasis in São Tomé and Príncipe

Podoconiosis or endemic non-filarial elephantiasis is produced by deposits of inorganic materials in the lymph node of the lower extremities. The presence of elephantiasis in São Tomé Island and its prevalence in two districts are documented. Epidemiological aspects of the disease as well as clinical and pathological data of some of the cases are illustrated. With all these data and the physical characteristics of the island we suggest that elephantiasis in São Tomé is of geological obstructive origin: podoconiosis. The importance of non-medical measures to eradicate this disease are underlined.

Effects of dothiepin on nociceptive flexion reflex and diffuse noxious inhibitory controls in humans

The analgesic activity of dothiepin (an antidepressant interacting with serotonin receptors) was studied (double-blind) in humans. A significant increase in nociceptive flexion reflex threshold and subjective pain threshold was observed after a 14-day dothiepin treatment. The effects of dothiepin on diffuse noxious inhibitory controls were also investigated using the cold-pressor test as conditioning stimuli. After dothiepin a reduced inhibition of nociceptive flexion reflex during the cold-pressor test and a significant facilitation immediately after the cold-pressor test were observed, while the subjective pain perception was normally inhibited. Our data suggest a serotonergic modulation of diffuse noxious inhibitory controls in humans.

The trigemino-pupillary response in cluster headache

Central impairment of the integrative neural systems controlling vegetative function and pain perception has been demonstrated in cluster headache (CH). Recently, we described the human pupillary response (trigeminal reflex) to quantified (painless and painful) corneal stimulation with a combined neurophysiological and pharmacological technique. In this study, the trigeminal reflex was evaluated in 26 subjects with episodic cluster headache. During the active phase of the disease, on the side of the pain we observed reduced mydriasis to electrical stimuli with an intensity equal to the corneal reflex threshold, and on both sides to stimuli with intensity that equalled the pain threshold. No difference was found when amplitude of the miotic phase was compared in the different groups. These suggest disordered pupillary activation in response to pain, probably sympathetic in origin, which is bilateral, detectable also during the remission phase and which cannot be explained simply by the antidromic release of pain-related peptides.

[Epidemiology of traveler's diarrhea in Spanish tourists travelling in developing countries]

BACKGROUND

Travellers' diarrhea (TD) is the most frequent problem in travellers going to the developing countries. This paper analyses the prevalence of the syndrome by geographical areas as well as the risk factors in 2209 Spanish travellers to 3 continents.

METHODS

Epidemiological data were gathered through a personnel interview filled by the travellers during their return trip. Those were introduce in a DbaseIII plus computer program and were evaluated through the Epi Info program.

RESULTS

The overall prevalence of TD found was 41%. The Indian subcontinent, the Middle East and Moghreb countries showed a higher prevalence of TD. Trekkers and people on boat cruises (Nile and Amazon) had the highest prevalence of TD. The consumption of non-carbonic drinks and ice creams was significantly associated to TD. Travellers with previous gastrointestinal illnesses suffered more TD than others.

CONCLUSIONS

Despite the fact that Spain in considered an area of intermediate risk for TD we found no significant differences in the prevalence of TD in Spanish travellers when compared with other published series from developed countries.

Etiology of traveller's diarrhea in Spanish travellers to developing countries

A cohort of 337 Spanish travellers to developing countries is presented. They all consulted us for traveller's diarrhea (TD). Bacteriological, parasitological and virological examinations were performed. A bacterial cause was found in 61.65% of travellers. Toxigenic and classical pathogenic Escherichia coli strains were the main bacterial agents. In comparison with other studies, Spanish travellers harboured Y. enterocolitica and EPEC organisms as a cause of TD. G. lamblia and E. histolytica were the most frequently isolated protozoa. Helminths were found in only 9 patients. No rotavirus infections were diagnosed. Previous antibiotic treatment had been taken by 161 patients. The percentage of isolated enteropathogens was similar in travellers who had previously taken antibiotic treatment and those who had not.

[Usefulness of the API ZYM system for the identification of Legionella sp]

BACKGROUND

The identification of Legionella genus is usually difficult, time consuming, and expensive. We decided to study the usefulness of API-ZYM system (Biomerieux) for Legionella species identification.

METHODS

A total of 96 strains (82 from Legionella genus and 14 from other bacterial genus) were included. We studied 19 different enzyme activities and we proceed following the manufacturers directions, with an incubation time for galleries of 4 hours at 37 degrees C.

RESULTS

Seventeen out of the 19 enzyme activities were uniformly positive or negative for Legionella sp. Thus, the sensitivity of these activities was 100% in identifying Legionella sp. Valine and cystine-arylamidase gave variable reactions for Legionella sp. strains. When the results of these enzyme test were compared to those of the control strains (Haemophilus influenzae, Pseudomonas aeruginosa) we observed that alkaline phosphatase, esterase, esterase-lipase, acid phosphatase and naphthol-AS-BI-phosphohydrolase in one side and esterase, esterase-lipase and leucin-arylamidase in the other side were able to differentiate Legionella sp. strains from P. aeruginosa and H. influenzae, respectively.

CONCLUSION

API SYM system is a simple, accurate and reproducible method for the identification of Legionella sp.

Schistosomiasis and the Dogon country (Mali)

A previously unknown area of schistosomiasis transmission is reported based on findings from a travelers' clinic in Barcelona. Three species of Schistosoma (S. haematobium, S. mansoni, and S. intercalatum) were diagnosed in a cluster of 43 patients who had been swimming in the Bandiagara and Bankas districts of Mali, where the Dogon people live. Three villages in the Bankas district appear to harbor these three species. The transmission potential of such a focus in this area is outlined. The travelers involved had little or no information on the risks of contracting schistosomiasis in that area. Obtaining a traveler's history, including accurate geographic data, is shown to be a crucial asset for improving epidemiologic research.

Multimodal evoked potentials in myotonic dystrophy (MyD)

By means of multimodal evoked potentials (EPs), we evaluated the central nervous system (CNS) involvement in 25 subjects suffering from myotonic dystrophy: brainstem auditory evoked potentials (BAEPs), middle-latency auditory evoked potentials (MLAEPs) and somatosensory evoked potentials (SEPs) from the upper limb were performed on all subjects, whereas only the 19 patients, whose clinical ocular abnormalities were slight, underwent pattern-electretinograms (PERGs) and pattern visual-evoked potentials (VEPs) in order to identify the site of lesion among visual pathways (retinal and/or retroretinal). PERGs were abnormal in 8/19 subjects, VEPs in 8/19 subjects (the two techniques were simultaneously abnormal in 8 eyes), BAEPs in 7/25 subjects, MLAEPs in 4/25 subjects (in one subject both BAEps and MLAEPs were abnormal) and SEPs were abnormal in 1/25 subjects. 13/25 of our subjects showed at least one EP that revealed a CNS involvement. The electrophysiological alterations were not correlated either with subject age or with disease duration. Multimodal EPs enabled us to demonstrate that CNS involvement in myotonic dystrophy is important and mainly affects the visual and auditory system.

[Epidemiologic, clinical and microbiological characteristics of enterotoxigenic E. coli as the cause of traveller's diarrhea]

We report a study of enterotoxigenic E. coli, that produces heat-labile, heat-stable or both toxins as agent of traveller's diarrhoea. Enterotoxigenic E. coli was isolated from stools of 71 (21%) patients out of a total of 337 traveller's that developed diarrhoea. Of all 71 strains isolated, 51 (15%) produces heat-labile toxin, 10 (3%) heat-stable toxin and 10 (3%) were able to produce both types of toxins. We also analyze the distribution of all cases according to the area visited, as well as the clinical features of traveller's diarrhoea due to enterotoxigenic E. coli.

[Cutaneous larva migrans in travelers]

Fifteen cases of cutaneous larva migrans (CLM) diagnosed in transcontinental travellers over a period of 4 years in the Department of Tropical Medicine in Hospital Clinic i Provincial of Barcelona were reviewed. The frequency of this disease as an imported pathology is on the increase and is related to the greater mobility of travellers today. Tourism is the main motive of the traveller and the geographic origin of the cases is cosmopolitan. The use of open footwear in 14 of the 15 patients is pointed out. The single lesion on the foot was the most frequent site. Thiabendazole was effective in 14 patients as was albendazole used in one patient. The secondary effects of thiabendazole, principally gastrointestinal disorders, headache, and dizziness are underlined.

Role of natural killer cells in the modulation of primary antibody production by purine nucleosides and their analogs

Previous results from this laboratory demonstrated that treatment of mice with the adenosine analog tubercidin (Tub) reduced natural killer (NK) cell activity while stimulating antibody production whereas the deoxyadenosine analog, 2-fluoroadenine arabinoside-5'-monophosphate (FaraAMP), produced opposite effects; i.e., it stimulated NK cell activity at doses that inhibited antibody formation (Cancer Res. 48, 4799, 1988). Since NK cells have been reported to play a suppressor role in immunoglobulin induction, it was hypothesized that the actions of Tub and FaraAMP on antibody production occurred secondary to their opposing effects on NK cells. To test this hypothesis, abilities of these nucleoside analogs to modulate primary antibody response to sheep red blood cells were evaluated in a C57BL/6 mutant mouse lacking NK cell activity (the beige mutation. C57BL/6-bg/bg). As previously found with C3H/He mice. NK cell activity was inhibited (Tub, doses 2-6 mg/kg/day for 3 days) or stimulated (FaraAMP, doses 75-250 mg/kg/day for 3 days) in heterozygous mice C57BL/6-bg/+. In support of the hypothesis, these nucleosides had no effect on primary antibody formation in the homozygous mutant mice at doses that clearly stimulated (Tub) or inhibited (FaraAMP) this immune response in heterozygous C57BL/6-bg/+ animals. This results was corroborated in C57BL/6 wild-type mice by abrogation of NK cell activity using a monoclonal antibody to the NK cell surface glycophisingolipid, ganglio-n-tetraosylceramide. We conclude that under the conditions of drug administration, modulation of primary antibody formation by Tub and FaraAMP in mice occurs indirectly via NK cells. Similar experiments using the potent ADA inhibitor, deoxycoformycin, indicated that its enhancement of primary antibody formation is independent of NK cell activity.

The trigeminal pupillary reflex as a model of vegetative-nociceptive interaction: physiological and clinical aspects

The study of pupil response to stimuli applied at the corneal level is particularly interesting for the study of integrative sensory-vegetative functions in both physiological and clinical research. In the present study we tried to evaluate and describe pupil response to quantified corneal stimuli in 7 healthy subjects by means of a binocular TV pupillometric device. The pupil response to corneal stimuli was bilateral, direct and consensual. It was characterized by a biphasic progression with an initial response in mydriasis and a later miotic component which was smaller, slower and of longer duration. A direct correlation was observed between the intensity of the stimulus applied and the extent of the mydriasis and between the intensity of the stimulus at the corneal level and the length of the mydriatic response.

A new 5-HT2 antagonist (ritanserin) in the treatment of chronic headache with depression. A double-blind study vs amitriptyline

The exact relationship between depression and chronic headache remains unclear. Considerable clinical and pharmacological evidence suggests the existence of a common biological terrain. Many antidepressant drugs are effective in the treatment of migraine and chronic headache disorders. Ritanserin, a new very selective serotonin-2 (5-HT2) antagonist, has recently shown both analgesic and antidepressant properties. The present study compares in a double-blind design, the effectiveness of ritanserin and amitriptyline, a well-known antidepressant extensively used in migraine prophylaxis. Thirty-eight patients (30 females and 8 males ranging in age from 20 to 50 yrs) were classified according to the International Headache Society criteria as: patients with chronic tension-type headache (CTH) (11 cases) and patients with coexisting migraine and CTH (MCTH) (27 cases). Only patients with a score equal to or higher than 18 on the Hamilton Rating Scale for Depression (HRSD) were included. Ritanserin was highly effective in reducing Pain Total Index and analgesic consumption in chronic headache, and its activity was similar to that observed during amitriptyline treatment. A significant improvement of HRSD and HRSA (Hamilton Rating Scale for Anxiety) scores was observed during both treatments. The main results of our study concern the demonstration of antiheadache and antidepressive properties of ritanserin. To better define the profile of the patients and their clinical responsiveness to the treatment, dexamethasone suppression test, clonidine test and nociceptive flexion reflex were investigated in our patients. Our data confirm the usefulness of these methods as markers of chronic headache with depression.

[Psychosis and cannabis consumption: study of the psychopathologic differences and risk factors]

The consumption of Cannabis has been related with different psychiatric disorders. However the role of this drug in the etiology of disorders has not yet precisely been established. It has been discussed that the existence of an Induced Psychosis is brought about by the consumption of Cannabis. The objective of our study is to determine if there exists specific characteristics in the psychotic disorders manifested after the Cannabis consumption in comparison with a group of Psychotics non consumers. We also defined the risk factors that influence the appearance of the psychopathologic troubles.

[Characteristics of the tuberculin reaction in Cantabria]

For the purpose of establishing the maximum cutoff point defining a positive tuberculin reaction in Cantabria, a study was made of a total of 1,814 school-age children, 7 and 14 years of age, selected at random from the school-age children in that region. 2 U of PPD RT-23 were used. It was observed that 26.8% of these children had a scar from having been vaccinated with BCG. The graph of induration frequencies is bimodal for both age groups and for those vaccinated and those not having been vaccinated. In the 5-9 mm. range, 69 (71%) of those studied had a scar, and 25 (26%) did not (p less than 0.001). In our region, a different cutoff point must be used for the purpose of this test: 5 mm. for screening and 10 mm. for estimating the prevalence of infection.

Auditory function in pediatric osteosarcoma patients treated with multiple doses of cis-diamminedichloroplatinum(II)

Serial auditory evaluations were performed in 54 pediatric patients (5 to 18 yr) treated with cis-diamminedichloroplatinum(II) for osteosarcoma. Each course of cis-diamminedichloroplatinum(II) comprised 150 mg/m2 and was administered initially at two weekly intervals for seven courses (3 mo) and subsequently at three monthly intervals for 15 to 21 mo. Overall, 604 courses were administered, and observations were conducted from diagnosis to 6 yr. Bilateral hearing loss was detected in all patients. The loss varied from mild (20 to 40 dB) to profound (greater than 90 dB). Initial losses occurred in the higher frequencies and were also greater at these frequencies. Significant loss was first observed after 300 mg/m2 for frequencies over 4000 Hz and gradually shifted to incorporate the lower frequencies. Hearing loss was permanent.

Age-related changes in excitability of nociceptive flexion reflex. An electrophysiological study in school-age children and young adults

By stimulating the sural nerve at the retromalleolar level and recording EMG response from biceps femoris muscle two components can be evoked: RII (shorter latency, lower threshold, non-nociceptive) and RIII (longer latency, higher threshold, nociceptive). RIII reflex represents a useful tool for pain research in humans since a close correlation exists between the reflex threshold and that of pain. In our study, latency, amplitude, duration and threshold of RII and RIII reflexes were investigated in school-age children (aged 7-14 years) and young adults. RIII threshold was significantly lowered in children, while the other parameters were similar in both groups. Our data suggest the existence of a reduced inhibitory descending control in nociceptive spinal neurones in children.

Influence of Dialysis Membranes on the Convective Transport of Middle Molecules

Ultrafiltrates from 10 patients in chronic maintenance hemodialysis (7 males and 3 females) were obtained simultaneously using three different membranes: cuprophan, polyacrilonitrile and polysulfone. Middle molecules (MM) chromatographic profiles and total MM amount were determined by gel chromatography and high performance liquid chromatography.

The convective transport of MM was similar and not membrane related. Hemofiltration, a predominantly convective solute transfer procedure using high flux membranes such as polyacrilonitrile and polysulfone, in which large amounts of fluids have to be ultrafiltered, is an effective form of MM removal.

Influence of dialysis membranes on the convective transport of middle molecules

Ultrafiltrates from 10 patients in chronic maintenance hemodialysis (7 males and 3 females) were obtained simultaneously using three different membranes: cuprophan, polyacrilonitrile and polysulfone. Middle molecules (MM) chromatographic profiles and total MM amount were determined by gel chromatography and high performance liquid chromatography. The convective transport of MM was similar and not membrane related. Hemofiltration, a predominantly convective solute transfer procedure using high flux membranes such as polyacrilonitrile and polysulfone, in which large amounts of fluids have to be ultrafiltered, is an effective form of MM removal.