Nongenomic effect of thyroid hormone on free-radical production in human polymorphonuclear leukocytes

Over the past few years increasing evidence has suggested the nongenomic effects of thyroid hormone, such as the activation of the signal transduction pathways and the activation of nuclear factor-kappaB by the induction of oxidative stress. The present study was undertaken to investigate the effect of thyroid hormone on human polymorphonuclear leukocytes (PMNLs) which are known as important sources of reactive oxygen species in the circulation. The production of superoxide anion (O2-) and the activity of myeloperoxidase were determined in the presence and absence of several inhibitors of the signalling pathway. L-thyroxine (T4) l-3,5,3'-tri-iodothyronine (T3) and L-3,5-di-iodothyronine (T2) stimulated O2- production in PMNLs in a dose-dependent manner within a few minutes of addition to cells. Thyroid hormone-stimulated O2- production was partially inhibited by pertussis toxin, an inhibitor of GTP-binding G protein, and was completely abolished by the protein kinase C inhibitors calphostin C and Ro-32-0432, and by a calcium chelator (BAPTA; bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid). Thyroid hormone stimulated myeloperoxidase activity and induced 125I- incorporation into PMNLs. Furthermore, thyroid hormone pre-incubation enhanced O2- production for n-formyl-methionyl-leucyl- phenylalanine (FMLP) stimulation. In conclusion, novel nongenomic actions of thyroid hormone, the induction of superoxide anion production and the stimulation of myeloperoxidase activity in PMNLs were demonstrated. The induction of O2- production requires calcium and is mediated by a pertussis toxin-sensitive G protein via stimulation of protein kinase C(s). These results suggest the existence of a membrane-bound binding site for thyroid hormone in PMNLs and a physiological role for thyroid hormone in the cellular defence mechanisms by stimulating free-radical production.

SPECT using 99mTc-DTPA for the assessment of disease activity in Graves' ophthalmopathy: a comparison with the results from MRI

Currently available methods for the estimation of disease activity in the orbits of patients with Graves' ophthalmopathy (GO) have the disadvantages of being either expensive or time consuming. The aim of this study was to develop a quick, reliable method using Tc labelled diethylenetriaminepentaacetic acid (DTPA) and four-headed single photon emission computed tomography (SPECT) for this purpose. The theoretical basis of the method is that the high capillarization and oedema in the orbit may be reflected on Tc-DTPA images in GO. SPECT data of 28 orbits of 14 patients with GO were compared with magnetic resonance imaging (MRI) T2 relaxation time scores. Based on the number of 'active' muscles with T2 relaxation times of more than 70 ms in a given orbit, an MRI score of 0 (no active muscle) to 4 (all rectus muscles active) was assigned to the orbit. With MRI, 18 orbits were inactive, and 10 were active. Thirty minutes after the intravenous administration of 7 MBq.kg Tc-DTPA, 128 projections were acquired by a four-headed SPECT. On the sum of six transaxial slices containing the entire bulbar region of the skull, a triangle-like region of interest (ROI) was drawn (OR ROI). This ROI was 'slipped' to the right temporal region of the brain as reference site (B ROI). The count ratios of OR/B were calculated and compared to MRI score values. In the group of 18 inactive orbits (an MRI score of zero on both sides), in the transaxial plane, the mean OR/B value was 6.4+/-1.17, and in the group of 10 active orbits (an MRI score of 1-3) 8.30+/-2.08, the difference being significant (P <0.05). Tc-DTPA orbital SPECT is a promising method for the estimation of disease activity in the orbits of patients with Graves' ophthalmopathy.

In vitro cell irradiation systems based on 210Po alpha source: construction and characterisation

One way of studying the risk to human health of low-level radiation exposure is to make biological experiments on living cell cultures. Two 210Po alpha-particle emitting devices, with 0.5 and 100 MBq activity, were designed and constructed to perform such experiments irradiating monolayers of cells. Estimates of dose rate at the cell surface were obtained from measurements by a PIPS alpha-particle spectrometer and from calculations by the SRIM 2000, Monte Carlo charged particle transport code. Particle fluence area distributions were measured by solid state nuclear track detectors. The design and dosimetric characterisation of the devices are discussed.

Seeing is believing? The form and substance of French medical debates over Lourdes

Recent works on Lourdes have tended to emphasize the positive personal, social, and spiritual aspects of a pilgrimage, while downplaying the role of religious politics in (over)determining discussions around the events taking place there over the course of the Third Republic. This paper seeks to reassert the extent to which the medical community remained divided, along religious lines, over the existence and nature of the cures taking place at Lourdes well into the twentieth century, while analyzing how Catholic physicians were able to create an aura of therapeutic credibility around the cures.

The impact of increased blood flow rates on recirculation in central venous hemodialysis catheters

A recent practice change in our unit from Quinton dual lumen PermCaths to Vas-Cath Optiflow central venous catheters resulted in the routine achievement of bloodflow rates (BFR) of 500 ml/min. Previously BFRs of 300-400 ml/min were the norm. The increased BFR was achieved without any apparent increase in venous pressure, prompting us to consider the possibility that increased recirculation was occurring. This paper presents the results of a study designed to answer the following questions: (a) What is the difference in recirculation rates between Quinton dual lumen PermCaths and Vas-Cath Optiflow dual lumen catheters? and (b) What is the impact of increased BFR on recirculation rates in Optiflow hemodialysis catheters? The study documented recirculation rates in two groups of patients. In Group 1, the Optiflow group, recirculation rates were calculated for 10 subjects, first at 350 ml/min and then at 500 ml/min. In Group 2, the PermCath Group, recirculation rates were calculated for 10 subjects at 300 ml/min. Paired t-tests were performed to compare Group 1 at 350 ml/min with Group 2. No significant differences were found within or between groups suggesting that recirculation rates were not affected by increased BFR.

High throughput cell-based assay of hematopoietic progenitor differentiation

The in vitro efficacy of drug candidates relative to hematopoietic stem cell proliferation and differentiation is currently assayed through use of the clonogenic "colony assay." The extremely low throughput of this assay precludes its use in library screening and much drug discovery work. A rapid-throughput assay of progenitor cell differentiation based on the quantification of hematopoietic lineage-specific markers has been developed. The CELISA assay employs a single incubation with a lanthanide-conjugated primary antibody and subsequent time-resolved fluorescence spectroscopy. The rapid-throughput nature of this assay is enhanced by the use of cell culture-compatible filter plates to reduce the number of manipulations as compared to currently available cell-based assays. The culture and assay are done in 96-well plates, and the quantitation process requires approximately 1 hour. The myeloid, erythroid, and megakaryocytic lineages can be objectively quantified; data from the assay correlate extremely well with data generated through use of the traditional colony assay. This assay makes possible both rapid-throughput drug discovery and toxicity screening in the area of hematopoiesis.

Growth and development in preterm infants fed long-chain polyunsaturated fatty acids: a prospective, randomized controlled trial

OBJECTIVES

A randomized, masked, controlled trial was conducted to assess effects of supplementing premature infant formulas with oils containing the long-chain polyunsaturated fatty acids, arachidonic acid (AA; 20:4 n6), and docosahexaenoic acid (DHA; 22:6 n3) on growth, visual acuity, and multiple indices of development.

METHODS

Infants (N = 470) with birth weights 750 to 1800 g were assigned within 72 hours of the first enteral feeding to 1 of 3 formula groups with or without long-chain polyunsaturated fatty acids: 1) control (N = 144), 2) AA+DHA from fish/fungal oil (N = 140), and 3) AA+DHA from egg-derived triglyceride (egg-TG)/fish oil (N = 143). Infants were fed human milk and/or Similac Special Care with or without 0.42% AA and 0.26% DHA to term corrected age (CA), then fed human milk or NeoSure with or without 0.42% AA and 0.16% DHA to 12 months' CA. Infants fed exclusively human milk to term CA (EHM-T; N = 43) served as a reference.

RESULTS

Visual acuity measured by acuity cards at 2, 4, and 6 months' CA was not different among groups. Visual acuity measured by swept-parameter visual-evoked potentials in a subgroup from 3 sites (45 control, 50 AA+DHA [fish/fungal]; 39 AA+DHA [egg-TG/fish]; and 23 EHM-T) was better in both the AA+DHA (fish/fungal; least square [LS] means [cycle/degree] +/- standard error [SE; octaves] 11.4 +/- 0.1) and AA+DHA (egg-TG/fish; 12.5 +/- 0.1) than control (8.4 +/- 0.1) and closer to that of the EHM-T group (16.0 +/- 0.2) at 6 months' CA. Visual acuity improved from 4 to 6 months' CA in all but the control group. Scores on the Fagan test of novelty preference were greater in AA+DHA (egg-TG/fish; LS means +/- SE, 59.4 +/- 7.7) than AA+DHA (fish/fungal; 57.0 +/- 7.5) and control (57.5 +/- 7.4) at 6 months' CA, but not at 9 months' CA. There were no differences in the Bayley Mental Development Index at 12 months' CA. However, the Bayley motor development index was higher for AA+DHA (fish/fungal; LS means +/- SE, 90.6 +/- 4.4) than control (81.8 +/- 4.3) for infants </=1250 g. When Spanish-speaking infants and twins were excluded from the analyses, the MacArthur Communicative Development Inventory revealed that control infants (LS means +/- SE, 94.1 +/- 2.9) had lower vocabulary comprehension at 14 months' CA than AA+DHA (fish/fungal) infants (100.6 +/- 2.9) or AA+DHA (egg-TG/fish) infants (102.2 +/- 2.8). There were no consistent differences in weight, length, head circumference, or anthropometric gains.

CONCLUSION

These results showed a benefit of supplementing formulas for premature infants with AA and DHA from either a fish/fungal or an egg-TG/fish source from the time of first enteral feeding to 12 months' CA.

Dealing with emergencies in rural areas of Europe: proceedings from WONCA Europe 2000

On 4 July 2000, two workshops on handling emergencies in rural areas of Europe were held at the WONCA (World Organisation of National Colleges and Academies of Family Medicine/General Practice) conference in Vienna under the auspices of EURIPA (European Rural and Isolated Practitioners' Association). Papers submitted covered varying patterns of service provision and examples of short intensive training for emergencies at resident and general practitioner levels. Ways of collecting data routinely for accident prevention were also discussed. The workshops concluded that there was a need for more research in the application of emergency skills, that lack of confidence in dealing with emergencies may contribute to recruitment problems, and that further work towards a document detailing training requirements for emergencies was needed. This will be developed at a EURIPA workshop at WONCA in Tampere, June 2001.

Prevalence of iodine deficiency and goitre during pregnancy in east Hungary

OBJECTIVE

To assess the iodine nutritional status and the prevalence of goitre during pregnancy in a region of Hungary that appeared to be iodine sufficient in previous studies.

DESIGN

A cross-sectional voluntary screening study was organized in which 313 pregnant women participated.

METHODS

Urine iodine concentration and the volume of the thyroid gland were measured in every woman. In the presence of low urinary iodine concentrations, goitre, or both, thyroid function tests were performed.

RESULTS

Iodine deficiency was found in 57.1% of the pregnant women, and was severe in 15.6%. The volume of the thyroid gland was enlarged in 19.2% of individuals. Nodular goitre was found in 17 women (5.4%). The frequency of goitre and the mean thyroid volume were increased in the group of iodine-deficient women. In the 89 cases of iodine deficiency or goitre, thyrotrophin concentrations were in the normal range; however, the free triiodothyronine:free throxine ratio was increased in 97% of them, indicating that the thyroid gland was in a stimulated state in these individuals.

CONCLUSIONS

Iodine deficiency with high prevalence of goitre was recognized among pregnant women in an area that previously appeared to be iodine sufficient. An unexpected mild iodine deficiency was also noted in the non-pregnant control group. Reassessment and continuous monitoring of iodine nutritional status is warranted even in populations that are apparently considered to be 'at no risk' of iodine deficiency, especially in pregnant women. Regular administration of iodine, starting at preconception or in early pregnancy and continuing during the period of nursing, is recommended in these regions.

Follow-up of prostate carcinoma patients treated with total androgen blockade by repeated map-biopsy

A prospective study was carried out on ten patients with prostate cancer. The TNM stage, Gleason's grade, general clinical status and, serum PSA level were all registered by the time of diagnosis. Total androgen blockade (TAB) was performed. Serum PSA control and general clinical examination re-biopsy was performed on average 107 days after the start of the therapy. The pre- and post treatment histology included HE and Tunel reaction to show apoptotic cells, as well as p53, bcl2 and Ki67 immunostaining. Clinical improvement of the disease, manifested by regression or by steady state was observed in all ten patients. An increase of apoptotic index, and a decrease of mitotic index was detected in most cases. The serum PSA level decreased in all patients. Ki67, bcl2 and mutant p53 were strongly expressed in tumor cells of patients in whom Gleason's grade was 7 or higher and decreased markedly in all cases upon therapy. Data obtained by repeated biopsy in the course of TAB therapy are indicators of the effectiveness of TAB, like changes in serum PSA, and may be considered as predictive factors.

Graves' ophthalmopathy: eye muscle involvement in patients with diplopia

BACKGROUND

Diplopia identifies patients with eye muscle involvement in Graves' ophthalmopathy (GO).

OBJECTIVE

To identify clinical parameters that could eliminate the need for magnetic resonance imaging (MRI) to assess the activity of inflammation in the eye muscles of GO patients with diplopia.

METHODS

In 43 patients with GO with recently developed diplopia, orbital ultrasound and MRI were performed. Muscle diameters and MRI T2 relaxation times were measured, and the amount of orbital connective tissue was calculated from MRI scans and compared with ultrasound readings, diplopia grades, degree of protrusion, ocular pressure, tear production, antibody levels and hormonal parameters of thyroid function.

RESULTS

No correlation was found between diameters of 233 extraocular muscles measured by MRI and by ultrasound. For each of the four muscles, there was a diameter above which ultrasound was always unreliable. MRI data were used in further analysis. Of the muscles examined, the inferior rectuses were the most frequently enlarged - at least one, in 93% of cases. Medial, lateral and superior rectuses were enlarged in 59%, 37% and 34% of the orbits respectively. The pattern of muscle involvement of the two orbits tended to be symmetric (r=0.49, P=0.003), particularly for the medial rectuses (r=0.90, P=0.000). Proptosis correlated with the sum of the muscle diameters for a given eye (right eye: r=0.54, P=0.003; left eye: r=0.57, P=0.001), but it failed to correlate with the amount of orbital connective tissue. In 53% of the patients, normal T2 relaxation times were found in all eight muscles. There was only a weak correlation between muscle thickness and T2 relaxation time (r=0.49, P=0.003), indicating that muscle enlargement alone is not a sign of disease activity. The severity of diplopia was independent of T2 relaxation time. The amount of orbital connective tissue showed a negative correlation with the greatest T2 relaxation time for a given eye (r= -0.52, P=0.004); this suggests that disease types exist that have predominant muscle involvement and predominant connective tissue expansion. No correlation between connective tissue expansion and proptosis, diplopia grade, muscle thickness or disease duration was found - that is, connective tissue expansion is not a major factor in diplopia. Both muscle and connective tissue findings were independent of thyroid function.

CONCLUSION

Ultrasound and MRI eye muscle diameter readings do not correlate, because of the inherent inaccuracy of orbital ultrasound. Muscle enlargement alone does not mean oedematous swelling and active disease. Neither ultrasound, nor any combination of 11 clinical and laboratory parameters provided the degree of information on muscles and connective tissue that was obtainable by MRI. In unclear cases of recently developed diplopia, before orbital decompression surgery, in the case of treatment failure or if, for any other reason, imaging is needed in GO, MRI is the method of choice.