ESR and optical absorption studies of gamma- and electron-irradiated sugar crystals

Electron spin resonance (ESR) studies of the free radicals induced in gamma- or electron-irradiated sugar crystals were performed. The number of radicals increases linearly, pointing out that this material can be used as a dosimeter. The optical absorption studies show the presence of several distinctive bands in the infrared and UV region, whose intensity changes with the irradiation dose. An interpretation of these results in terms of the formation of free radicals and possible crosslinking along the sugar molecular chains is presented.

Increased phosphoinositide 3-kinase activity induces a lymphoproliferative disorder and contributes to tumor generation in vivo

Alterations in the cell division:cell death ratio induce multiple autoimmune and transformation processes. Phosphoinositide 3-kinase (PI3K) controls cell division and cell death in vitro, but its effect on the function of the cellular immune system and on tumor formation in mammals is poorly characterized. Here we show that transgenic mice expressing in T lymphocytes an active form of PI3K derived from a thymic lymphoma, p65(PI3K), developed an infiltrating lymphoproliferative disorder and autoimmune renal disease with an increased number of T lymphocytes exhibiting a memory phenotype and reduced apoptosis. This pathology was strikingly similar to that described in mice exhibiting heterozygous loss of the tumor suppressor PTEN, a lipid and protein phosphatase. We show that overexpression of PTEN selectively blocks p65(PI3K)-induced 3T3 fibroblast transformation. Moreover, the early development of T cell lymphomas in p65(PI3K) Tg p53(-/-) mice indicated that PI3K contributes to tumor development. These observations demonstrate that constitutive activation of PI3K extends T cell survival in vivo, affects T cell homeostasis, and contributes to tumor generation, supporting a model in which selective increases in one type of PTEN substrate, the PI3K-derived lipid products, induce tumorigenesis. PI3K thus emerges as a potential target in autoimmune disease and cancer therapy.

New radiopharmaceuticals for receptor scintigraphy and radionuclide therapy

In vitro data have demonstrated a high amount of receptors for various hormones and peptides on malignant cells of neuroendocrine origin. Among these, binding sites for members of the SST-family (hSSTR1-5) are frequently found, and their expression has led to therapeutic and diagnostic attempts to specifically target these receptors. Receptor scintigraphy using radiolabeled peptide ligands has proven its effectiveness in clinical practice. In addition, initial results have indicated a clinical potential for receptor-targeted radiotherapy. Based on somatostatin (SST) receptor (R) recognition, the novel radiopharmaceuticals 111In/90Y-DOTA-lanreotide developed at the University of Vienna as well as 111In/90Y-DOTA-DPhe1-Tyr3-octreotide (NOVARTIS) both have provided promising data for diagnosis and treatment of hSSTR-positive tumors. SSTR scintigraphy using 111In-DTPA-DPhe1-octreotide has a high positive predictive value for the vast majority of neuroendocrine tumors and has gained its place in the diagnostic work-up as well as follow-up of patients. We have used 111In-DOTA-lanreotide scintigraphy in 166 patients since 1997 and have seen positive results in 93% of patients. In 42 patients with neuroendocrine tumors comparative data were obtained. As opposed to 111In-DTPA-DPhe1-octreotide and 111In-DOTA-DPhe1-Tyr3-octreotide, discrepancies in the scintigraphic results were seen in about one third of patients concerning both the tumor uptake as well as tumor lesion detection. Initial results both with 90Y-DOTA-lanreotide as well as 90Y-DOTA-DPhe1-Tyr3-octreotide has pointed out the clinical potential of radionuclide receptor-targeted radiotherapy. This new therapy could offer palliation and disease control at a reduced cost. The final peptide therapy strategy is most probably cheaper than conventional radiotherapies or prolonged chemotherapies. Overall, receptor-mediated radiotherapy with 90Y-DOTA-lanreotide/90Y-DOTA-DPhe1-Tyr3-octre otide might also be effective in patients refractory to conventional strategies.

Chondrotoxicity of ciprofloxacin in immature beagle dogs: immunohistochemistry, electron microscopy and drug plasma concentrations

The systemic effects of ciprofloxacin in immature Beagles were studied. Dogs of 10-11 weeks were dosed orally for 5 days with 0 (n=3), 30 (n=5) and 200 (n=5) mg ciprofloxacin/kg body wt. Plasma concentrations were measured by high-performance liquid chromatography (HPLC) 1 h after dosing (assuming to be peak concentrations). In view of the high doses used, the plasma concentrations were rather low and declined during the study period. For example, plasma concentrations in the high dose group were 6.6 +/- 0.9 mg/l (day 1), 3.9 +/- 1.4 mg/l (day 3), and 2.6 +/- 1.6 mg/l (day 5). In control dogs and in dogs treated with the low dose of ciprofloxacin no pathological changes were seen by light microscopy. However, cleft formation and erosions were observed in joint cartilage from two of five dogs treated with 200 mg/kg. It is noteworthy that despite the high dose used cartilage lesions were not detectable in all five dogs of this group by light microscopy. Using antibodies against cell membrane receptors (e.g. the alpha(5)beta(1)-integrin) or matrix components (fibronectin, collagen II) the articular cartilage effects were studied in detail by immunohistochemistry. The most sensitive alteration was an increase in fibronectin which was detectable in the vicinity of the lesions in cartilage samples from the group of dogs administered the high dose. No clear-cut changes were seen with the use of antibodies against other matrix components. Electron microscopy revealed typical alterations in chondrocytes from dogs treated with ciprofloxacin: e.g., swollen mitochondria and enlarged rough endoplasmic reticulum. These changes were much more pronounced in dogs from the high dose group than in dogs from the low dose group. Our main conclusion is that after oral administration ciprofloxacin exhibits rather low chondrotoxicity, even in the most sensitive species known to date. This correlates with the findings in humans that ciprofloxacin seems to be less chondrotoxic than pefloxacin or other quinolones.

[Respiratory form of onset of motor neuron disease]

OBJECTIVE

To present a case of respiratory failure as the form of onset of amyotrophic lateral sclerosis, to review the main clinical findings, data of the investigations done which suggest the presence of this disorder and describe its therapeutic management.

CLINICAL CASE

A 68 year old man presented with a subacute illness characterized by a sleep disorder with sleep fragmentation, snoring of increasing intensity, without clear pauses of apnea, progressive diurnal hypersomnia accompanied by progressive dyspnea followed by respiratory failure with respiratory acidosis and difficulty in manipulating things with his hands. Diagnostic investigations showed a restrictive pattern without pulmonary fibrosis, due to paralysis of the diaphragm, and the presence of electromyographic signs compatible with motorneuron disease. The patient was treated with riluzole 100 mg/day and non-invasive mechanical ventilation and maintained an acceptable quality of life.

CONCLUSIONS

Motorneuron disease may start with acute or progressive respiratory failure without a clear etiological cause and may appear to be similar to obstructive sleep apnea syndrome. The treatment of choice for this respiratory problem is non-invasive mechanical ventilation. Absence of symptoms of bulbar involvement is essential for a favourable prognosis.

Nitric oxide and carbon monoxide modulate oscillations of olfactory interneurons in a terrestrial mollusk

Spontaneous or odor-induced oscillations in local field potential are a general feature of olfactory processing centers in a large number of vertebrate and invertebrate species. The ubiquity of such oscillations in the olfactory bulb of vertebrates and analogous structures in arthropods and mollusks suggests that oscillations are fundamental to the computations performed during processing of odor stimuli. Diffusible intercellular messengers such as nitric oxide (NO) and carbon monoxide (CO) also are associated with central olfactory structures in a wide array of species. We use the procerebral (PC) lobe of the terrestrial mollusk Limax maximus to demonstrate a role for NO and CO in the oscillatory dynamics of the PC lobe: synthesizing enzymes for NO and CO are associated with the PC lobes of Limax, application of NO to the Limax PC lobe increases the local field potential oscillation frequency, whereas block of NO synthesis slows or stops the oscillation, the bursting cells of the PC lobe that drive the field potential oscillation are driven to higher burst frequency by application of NO, the nonbursting cells of the PC lobe receive trains of inhibitory postsynaptic potentials, presumably from bursting cells, due to application of NO, and application of CO to the PC lobe by photolysis of caged CO results in an increase in oscillation frequency proportional to CO dosage.

Effects of magnesium deficiency on joint cartilage in immature beagle dogs: immunohistochemistry, electron microscopy, and mineral concentrations

Quinolone-induced chondrotoxicity is possibly associated with the magnesium-chelating properties of quinolones. This toxic effect seems to be restricted to a rather short time period during postnatal development as shown in rats and dogs. We studied developmental changes of the integrin pattern on canine chondrocytes (e.g. the alpha(v)beta(3)- or alpha(5)beta(1)-integrin), because integrin function depends on divalent cations, as well as the matrix composition (e.g., collagen type II, fibronectin), in 11-, 18-, and 55-week-old Beagles (n=8) by immunohistochemistry. We also analyzed the magnesium and calcium content by atomic absorption spectroscopy in cartilage and bone and studied the effects of a magnesium-deficient diet on joint cartilage in four immature Beagles (18 weeks old at necropsy). The dogs were fed the magnesium-deficient diet for 40 to 46 days. All dogs exhibited gait alterations ('limping') after 4 weeks on the magnesium-deficient diet. Male, magnesium-deficient dogs exhibited pronounced weakness in their front legs; in one of these dogs the front legs were hyperextended to a 90 degrees angle. We observed no significant differences in the integrin pattern in samples from dogs at different developmental stages or in magnesium-deficient dogs in comparison to age-matched controls. Localization of fibronectin in the joint cartilage was found to vary with the age of the dogs as well as with the site of collection. In the middle zone of immature joint cartilage, corresponding to the predilective site of quinolone-induced cartilage lesions, we observed a slight increase in staining with the fibronectin antibody in some samples from magnesium-deficient dogs. Electron microscopy revealed alterations in chondrocytes from the magnesium-deficient dogs (e.g., swollen mitochondria and enlarged endoplasmic reticulum) which are also seen after treatment with quinolones. In summary, we found no significant differences of the integrin pattern on chondrocytes from joint cartilage of dogs at various developmental stages. However, magnesium deficiency in immature dogs induced similar clinical symptoms as quinolone treatment as well as distinct alterations in chondrocytic fibronectin staining and their ultrastructure. This corroborates our findings in rats where magnesium chelation is an important event in quinolone-induced chondrotoxicity.

Dermatitis herpetiformis is associated with atrophic but not with goitrous variant of Hashimoto's thyroiditis

BACKGROUND

Dermatitis herpetiformis (DH) is a gluten-sensitive skin disease that is associated with a variety of autoimmune disorders. Several investigations demonstrated an association between DH and autoimmune thyroid disease. However, it has not been shown if DH is associated with atrophic or goitrous variant of Hashimoto's thyroiditis.

MATERIALS AND METHODS

We investigated a cohort of 41 DH patients (18 male, 23 female) and a control group (11 male, 19 female; sex and age matched healthy volunteers) to find out which variant of Hashimoto's thyroiditis is associated with DH. All patients had thyroid hormones and antibodies measured. In addition to that, thyroid sonography as well as detailed history-taking of previous thyroid disease were performed.

RESULTS

In the control group no individual with elevated levels of thyroid antibodies nor abnormal thyroid hormones nor thyroid atrophy was found. Median thyroid volume in the control group was 11 mL (range 4.8-24.7 mL). However, in nine DH patients (22%) elevated levels of antithyroid microsomal (TM) antibodies were seen (P < 0.01). Three of them had abnormal thyroid hormones (7%). In the group of DH patients a significantly smaller thyroid volume was found (median 8 mL, range 1. 6-25.2 mL; P < 0001). Thyroid atrophy (volume < 4.4 mL) was found in 10 DH patients (24%) of whom 9 were females. All patients with elevated levels of TM antibodies or abnormal thyroid hormones and all patients with a history of previous hypothyroidism had a thyroid volume < 7 mL. Goitrous variant of Hashimoto's thyroiditis was not seen in any of the DH patients.

CONCLUSIONS

Our findings demonstrate that DH is associated with atrophic but not with goitrous variant of Hashimoto's thyroiditis.

Differentiated thyroid cancer in children and adolescents: the importance of adequate surgery and review of literature

Within 25 years, 13 girls and 5 boys between the ages of 9 to 20 years were treated for differentiated thyroid cancer (DTC) at our institution. In 67% of the cases the diagnosis was made at an advanced stage indicated by cervical lymphnode metastases, two children showed metastases of the lung. Except for one girl, all patients underwent a total thyroidectomy with various forms of lymph node dissections. All were treated post-surgically with radio-iodine (131I) and all patients received levothyroxine in suppressive doses. The complication rate was low (laryngeal nerve injury in only 3 cases and no permanent hypoparathyroidism) and after a follow-up period of 26 years all patients are alive and without disease. In the case of DTC in children and adolescents, a total thyroidectomy with an appropriate lymph node dissection is the best surgical management. Besides the rather high incidence of local and distant recurrence, particularly in this age group, the detection and treatment of the metastases with radio-iodine are significantly facilitated by this surgical procedure. Additionally it allows the use of serum thyroglobulin as a reliable indicator of recurrence. To prevent high complication rates, surgical treatment should be performed in centers with skilled and experienced endocrine surgeons.

[Dose-effect of the administration of ferrous fumarate in aged persons with iron deficiency]

BACKGROUND

Anemia is the most prevalent hematological problem in elderly persons, affecting 14% of the males and 6% of the females of the population over 60 years of age in Mexico City.

OBJECTIVE

To determine the effect produced by the prolonged administration of ferrous fumarate in elderly persons with iron deficiency.

METHOD

In a population of 178 subjects, aged between 65 to 100 years, iron deficiency was diagnosed in 51 (28.6%), who had serum iron concentrations below 80 micrograms/dL for men and 60 micrograms/dL for women, but only 21 patients (11.8%), accepted to participated in the study. The response to a 6 months oral administration of ferrous fumarate were studied with a daily oral dose of 5 mg/kg of elemental iron. The patients were classified in 3 groups according to the abnormal parameters of iron metabolism (group 1 = 10.9% anemia, group 2 = 28.0% and group 3 = 63.0% anemia).

RESULTS

The efficacy of treatment was evaluated by quantification of the changes occurred in serum iron concentrations, hemoglobin, ferritin and transferrin saturation index, at 0, 30, 90 and 180 days of treatment. This study showed that the treatment of oral ferrous fumarate in elderly patients with iron deficiency, produces a quantifiable improvement in measures of iron parameters within 6 months.

CONCLUSIONS

The results of this study suggest the usefulness of prolonged treatment with ferrous fumarate in elderly patients with iron deficiency, to avoid therapeutic failure as a consequence of non-compliance as is common in elderly patients.

[Properties of stored platelet concentrates: effect of the suspension media and type of pouch used]

PURPOSE

We have evaluated in vitro the effects of using plasma (group A) or PAS-2 (group B) in storing platelets, regarding as well the type of container (conventional polyolefin--PL732--or new oxygen permeable platelet containers--PL2410, Compoflex--), on the metabolism of platelet concentrates--PC--from pools of five buffy coats.

MATERIAL AND METHODS

87, A and B pools of PCs collected in two types of bags were studied. The samples were taken on days 2, 5 and 7, and cell counts, pH, glucose, platelet activation (% CD62) and aggregation response were measured.

RESULTS

In group A, when we compared the two types of bags, we observed a difference (p < 0.01) in values of pH and glucose on day 5. These values were more advantageous in new oxygen permeable platelet containers. The rest of the parameters analysed didn't show significant differences. When we compared the PL-2410 containers from groups A and B, we found a lower level of glucose (p < 0.01) in group B, although the levels of glucose in this group on days 5 and 7 of storage were sufficient to support the platelet metabolism.

CONCLUSIONS

The use of new oxygen permeable polyolefin containers and additive solutions, PAS-2, allows us to obtain pools of PC with suitable metabolic parameters during storage.

Semi-Poisson statistics and beyond

Semi-Poisson statistics are shown to be obtained by removing every other number from a random sequence. Retaining every (r+1)th level we obtain a family of sequences, which we call daisy models. Their statistical properties coincide with those of Bogomolny's nearest-neighbor interaction Coulomb gas if the inverse temperature coincides with the integer r. In particular, the case r=2 reproduces closely the statistics of quasioptimal solutions of the traveling salesman problem.

Utility of the polymerase chain reaction in detection of Trypanosoma cruzi in Guatemalan Chagas' disease vectors

For effective control programs, accurate assessment of Trypanosoma cruzi infection in vectors is essential and has traditionally been performed by microscopic examination. For particular vectors and not others, polymerase chain reaction (PCR) analysis of fecal samples recently has been shown to be an effective means of detection. The sensitivities of the PCR and microscopy for detection of T. cruzi in different anatomic sites were compared in the two major vectors of Guatemala, Triatoma dimidiata and Rhodnius prolixus. Preliminary studies established that T. cruzi can be detected by the PCR in the presence of 90% T. rangeli. One hundred thirty-five vectors were collected, and samples were obtained from the rectum, intestines, and stomach and analyzed by microscopy and the PCR. For Triatoma dimidiata rectal samples, the PCR sensitivity (39.1% T. cruzi positive) and the microscopic sensitivity (24.6% positive) was not significantly different. However, in R. prolixus, the PCR proved significantly more sensitive than microscopy: 57.6% positive by PCR compared with 22.7% by microscopy. Rectal samples showed the highest rates of infection followed by intestine and stomach samples. However, 10.5% of the Rhodnius infections would have been missed if only the rectal sample had been analyzed. Thus, the PCR is significantly more sensitive than microscopy for detection of T. cruzi in R. prolixus. Analysis of anatomic sites in addition to the rectal sample may be necessary for accurate assessment of infection in particular vectors.

Effect of nitrate and nitrite curing salts on microbial changes and sensory quality of non-fermented sausages

The effects of nitrate and nitrite curing salts on microbial changes and sensory quality of non-fermented sausages of small diameter were investigated. During pre-ripening (day 5), levels of lactic acid bacteria and yeasts were slightly higher in nitrite-made sausages than in those made with nitrate. In contrast, nitrite discouraged the growth of psychrotrophs as occurs in fermented sausages. By the end of ripening (day 26), levels of microorganisms were similar in both batches of sausages except for psychrotrophs being higher in those made with nitrite. Nitrate-made sausages showed higher aroma and taste intensity.

Comparison of three ELISA tests for seroepidemiology of bovine fascioliosis

The aim of the present study was to compare the sensitivity, specificity and usefulness of the DIG-ELISA, DOT-ELISA and Indirect ELISA tests for determining the seroprevalence of fasciolosis in cattle under tropical conditions in Mexico. To standardize the tests, positive and negative sera to F. hepatica from 88 Holstein Freisian adult cows located in an enzootic area of fascioliosis and 88 crossbred adult cattle from a fluke-free area were used. For the epidemiological study, 85 crossbred cattle between 1 to 7 years of age were used. Animals were bled every two months, from March 1995 to September 1996 and the sera obtained were stored at -70 degrees C, until used. Indirect ELISA showed a sensitivity of 96.5% and a specificity of 98.8%, DIG-ELISA 97.5% and 80.0% and DOT-ELISA 93.1% and 95.4%, respectively. During 1995, Indirect ELISA yielded the highest levels of IgG anti-F. hepatica antibodies. However, in 1996, after animal treatment with triclabendazole, DIG-ELISA tended to show higher percentages of antibody-positive animals, but it was not significantly different (p>0.05) from the other tests. Comparisons made in parallel to the faecal sedimentation test demonstrated that all serological tests detected higher percentages of positive animals. Only one serum out of ten (10%) of Paramphistomum spp. cross-reacted with the DOT-ELISA test, but no cross-reaction was observed with sera from animals with other parasites. All ELISA tests were highly sensitive and specific; they may be recommended for use in seroepidemiological surveys for F. hepatica.

Minimal model of oscillations and waves in the Limax olfactory lobe with tests of the model's predictive power

Propagating waves are observed in the olfactory or procerebral (PC) lobe of the terrestrial mollusk, Limax maximus. Wave propagation is altered by cutting through the various layers of the PC lobe both parallel and transverse to the direction of wave propagation. We present a model for the PC lobe based on two layers of coupled cells. The top layer represents the cell layer of the PC lobe, and the bottom layer corresponds to the neuropil of the PC lobe. To get wave propagation, we induce a coupling gradient so that the most apical cells receive a greater input from neighbors than the basal cells. The top layer in the model is composed of oscillators coupled locally, whereas the bottom layer is comprised of oscillators with global coupling. Odor stimulation is represented by an increase in the strength of coupling between the two layers. This model allows us to explain a number of experimental observations: 1) the intact PC lobe exhibits regular propagating waves, which travel from the apical to the basal end; 2) there is a gradient in the local frequency of slices cut transverse to the axis of wave propagation, with apical slices oscillating faster than basal slices; 3) with partial cuts through the cell layer or the neuropil layer, the apical and basal ends remain tightly coupled; 4) removal of the neuropil layer does not prevent wave propagation in the cell layer; 5) odor stimulation causes the waves to collapse and the cells in the PC lobe oscillate synchronously; and 6) by allowing a single parameter to vary in the model, we capture the reversal of waves in low chloride medium.

[Development of an enzyme assay for detection of hepatitis B virus core IGM antibodies]

Detection of IgM anti-core (anti-HBcAg) antibodies of Hepatitis B Virus (HBV) is an useful marker for hepatitis B virus (HBV) acute infection. The aim of this study was to perform an immunodiagnostic assay for the detection of IgM anti-HBcAg antibodies. Hepatitis B core antigen (HBcAg) was produced by a recombinant clone of Escherichia coli and used for the development of the immunoassay. An IgM capture enzyme immunoassay (EIA) was selected for the detection of IgM anti-HBcAg antibodies. A total of 110 human plasma or sera were tested by the capture EIA and a commercial assay. The capture EIA yielded 99% of sensitivity and 93% specificity, when compared with the commercial test. The capture EIA developed here is of interest for epidemiological studies, particularly for endemic regions in South America.