Evaluating the intensity of the 803-keV γ ray of 210Po using a 4παβ(LS)-γ(HPGe) measurement system

The absolute intensity for the 803-keV γ ray of ²¹⁰Po was evaluated by α-γ coincidence technique. A liquid sample with a known amount of ²¹⁰Po embedded in scintillation fluid was measured in a coincidence-based system that comprises a Liquid Scintillator (LS) detector and a High-Purity Germanium (HPGe) detector. A photo-reflector assembly that contains the ²¹⁰Po sample provides 100% efficiency for detecting the α particles. The combination between the HPGe and the LS detectors allows to reject non-coincident α-γ events while maintaining high resolution γ spectroscopy. Consequently, the faint 803-keV photopeak from ²¹⁰Po could be observed in a background-free environment, and its intensity could be evaluated with good accuracy. Sample measurements were carried out over nine months to gather statistics and verify the reliability of the experimental procedure. The absolute intensity of the 803-keV line was found to be (1.22 ± 0.03) × 10^-5, in excellent agreement with the adopted value in a recent data compilation and consistent with previous experimental works.

The Fate of Eyes with Anterior Chamber Intra-Ocular Lenses

A total of 143 anterior chamber (AC) intra-ocular lenses (IOL) of various designs were implanted in a five-year period and followed for 18 to 76 months. The lenses were inserted as a secondary implant after extracapsular cataract extraction (ECCE) complicated by vitrectomy, or after primary intra-capsular extraction. The complications (corneal edema, uveitis/glaucoma, extrusion/imbedding, cystoid macular edema), the final visual acuity and the need for removal of the IOL were analyzed. Only small differences were found between the different lenses but some association was found between complicated surgery (ECCE + vitrectomy) and a higher rate of complication, poorer visual outcome and more frequent need for IOL removal. Cystoid macular edema was encountered only in cases with complicated ECCE. A high percentage of other ocular pathologies was found among the cases, possibly implying that diseased eyes are more prone to surgical complications. An alternative to the AC-IOL in cases with a ruptured posterior capsule is the suture-supported posterior chamber IOL, but the flexible-loop AC-IOL may not yet be obsolete.

Effects of radiodetoxified endotoxin on nitric oxide production in J774 macrophages and in endotoxin shock

Radiodetoxified lipopolysaccharide (RD-LPS) is a 60Co-gamma-irradiated LPS with a modified structure, which decreases its toxic effects. To obtain a better understanding of the mechanism of the reduced toxicity of RD-LPS, here we studied the effect of RD-LPS on the regulation of nitric oxide (NO) production in vitro and in vivo. In control cells, stimulation by native LPS (10 μg/ml) induced the expression of the inducible NO synthase (iNOS) and production of NO, as measured by increase in the concentration of nitrite, breakdown product of NO. Pre-exposure of the cells for 24 h to a subthreshold concentration of RD-LPS (10 ng/ml) induced a complete desensitization to the LPS-induced NO production in comparison to control cells (P < 0.01). On the contrary, pre-exposure of the cells with native LPS (10 ng/ml) did not reduce LPS-induced NO synthesis. RD-LPS induced a smaller production of tumor necrosis factor (TNF) than native LPS, but did not induce a desensitization against subsequent LPS-induced TNF synthesis. ln in vivo studies, pretreatment of rats with repeated doses of sublethal RD-LPS (1 mg/kg/day i.p. for 4 days) inhibited increase of plasma nitrate/nitrite levels, NO production in peritoneal macrophages ex vivo and induction of lung iNOS activity, in response to a high-dose LPS challenge (15 mg/kg i.p.) given at the fifth day. Pretreatment with repeated sublethal doses of the native LPS (1 mg/kg/day i.p.) did not affect NO production in rats subjected to endotoxic shock. The results demonstrate that RD-LPS induces tolerance to the stimulatory effect of LPS on NO synthesis. Suppression of iNOS induction was only observed with RD-LPS, but not with native LPS in the models used herein. It remains to be further investigated whether suppression of iNOS induction by RD-LPS contributes to the protective effects of this compound in shock and inflammation.

Endemic disease, awareness, and local behavioural response

The spread of a contagious disease is often accompanied by a rise in awareness of those in the social vicinity of infected individuals, and a subsequent change in behaviour. Such reactions can manifest themselves in lower susceptibility as people try to prevent themselves from catching the disease, but also in lower infectivity because of self-imposed quarantine or better hygiene, shorter durations of infectiousness or longer immunity. We here focus on the scenario of an endemic disease of which members of the population can be either aware or unaware, and consider a broad set of possible reactions. We quantify the impact on the endemicity of a disease in a well-mixed population under the variation of different disease parameters as a consequence of growing awareness in the population. Applying a pair-closure scheme allows us to analyse the effect of local correlations if aware individuals tend to occur near infected cases, and to link this to the amount of overlap between the networks underlying the spread of awareness and disease, respectively. Lastly, we study the consequences on the dynamics when the pathogen and awareness spread at different velocities.

Dynamics and spatial organization of plant communities in water-limited systems

A mathematical model for plant communities in water-limited systems is introduced and applied to a mixed woody-herbaceous community. Two feedbacks between biomass and water are found to be of crucial importance for understanding woody-herbaceous interactions: water uptake by plants' roots and increased water infiltration at vegetation patches. The former acts to increase interspecific competition while the latter favors facilitation. The net interspecific interaction is determined by the relative strength of the two feedbacks. The model is used to highlight new mechanisms of plant-interaction change by studying factors that tilt the balance between the two feedbacks. Factors addressed in this study include environmental stresses and patch dynamics of the woody species. The model is further used to study mechanisms of species-diversity change by taking into consideration tradeoffs in species traits and conditions giving rise to irregular patch patterns.

A mathematical model of plants as ecosystem engineers

Understanding the structure and dynamics of plant communities in water-limited systems often calls for the identification of ecosystem engineers--key species that modify the landscape, redistribute resources and facilitate the growth of other species. Shrubs are excellent examples; they self-organize to form patterns of mesic patches which provide habitats for herbaceous species. In this paper we present a mathematical model for studying ecosystem engineering by woody plant species in drylands. The model captures various feedbacks between biomass and water including water uptake by plants' roots and increased water infiltration at vegetation patches. Both the uptake and the infiltration feedbacks act as mechanisms for vegetation pattern formation, but have opposite effects on the water resource; the former depletes the soil-water content under a vegetation patch, whereas the latter acts to increase it. Varying the relative strength of the two feedbacks we find a trade-off between the engineering capacity of a plant species and its resilience to disturbances. We further identify two basic soil-water distributions associated with engineering at the single patch level, hump-shaped and ring-shaped, and discuss the niches they form for herbaceous species. Finally, we study how pattern transitions at the landscape level feedback to the single patch level by affecting engineering strength.

Lipopolysaccharide hyporesponsiveness as a risk factor for intensive care unit hospitalization in infants with respiratory syncitial virus bronchiolitis

Factors such as genetic heterogeneity in the immune response contribute to respiratory syncytial virus (RSV) bronchiolitis severity. Such heterogeneity may manifest by an aberrant proliferation of phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) in response to lipopolysaccharide (LPS). The proliferation of PBMC was analysed in 52 infants: 21 ambulatory infants with mild RSV bronchiolitis (group I), 26 hospitalized infants with RSV bronchiolitis on ward (group II) and five intensive care unit (ICU) hospitalized infants (group III). Proliferation was analysed in response to negative control, PHA (LPS) and LPS/PHA. The TLR4 mutations were genotyped using reverse-transcriptase-polymerase chain reaction. The optical density (OD) post-LPS/PHA of group II (1.27 +/- 0.63) was significantly higher than group II (0.65 +/- 0.38, P = 0.005) or group I (0.63 +/- 0.33, P = 0.003), suggesting hyporesponsiveness to the LPS attenuation effect. None of the ICU hospitalized infants demonstrated OD readings post-LPS/PHA under the 0.75 threshold as opposed to group I (67% under 0.75) and group II (69%) (P < 0.05). The responses to negative-control, LPS and PHA stimulation alone were similar across groups. The presence of TLR4 mutations (Asp299Gly and Thr399Ile) were associated with severe RSV bronchiolitis and were significantly over-represented in groups II and III. These findings suggest that impairments of PBMC function manifested by hyporesponsiveness to LPS as well as the presence of TLR4 mutations are associated with an increased risk for more severe RSV bronchiolitis in previously healthy infants. A certain threshold of LPS hyporesponsiveness may have a very high negative predictive value for ICU hospitalization, even better than the determination of known TLR4 mutations for this purpose.

Fulminant neurological deterioration in a neonate with Leigh syndrome due to a maternally transmitted missense mutation in the mitochondrial ND3 gene

Leigh syndrome can result from both nuclear and mitochondrial DNA defects. Mutations in complex V genes of the respiratory chain were considered until recently as the most frequent cause for mitochondrial inherited Leigh syndrome, while gene defects in complex I were related to recessive Leigh syndrome. Recently few reports of mutations in the mitochondrial-encoded complex I subunit genes causing Leigh syndrome have been reported. We describe a 1-month-old baby who acutely deteriorated, with abrupt onset of brainstem dysfunction, due to basal ganglia lesions extending to the brainstem. A muscle biopsy demonstrated complex I deficiency. Subsequent analysis of the mitochondrial genome revealed a homoplastic T10191C mutation in the ND3 gene (in blood and muscle), resulting in a substitution of serine to proline. Hair root analysis revealed a 50% mutant load, reflecting heteroplasmy in early embryonic stages. The mutation was also detected in his mother (5%). Western blot analysis revealed a decrease of the 20 kDa subunit (likely ND6) and of the 30 kDa subunit (NDUFA9), which is probably due to instability attributed to the inability to form subcomplexes with ND3. This is the first description of infantile Leigh syndrome due to a maternally transmitted T10191C substitution in ND3 and not due to a de novo mutation. This mutation is age and tissue dependent and therefore may not be amenable to prenatal testing.

Ecosystem engineers: from pattern formation to habitat creation

Habitat and species richness in drylands are affected by the dynamics of a few key species, termed "ecosystem engineers." These species modulate the landscape and redistribute the water resources so as to allow the introduction of other species. A mathematical model is developed for a pair of ecosystem engineers commonly found in drylands: plants forming vegetation patterns and cyanobacteria forming soil crusts. The model highlights conditions for habitat creation and for high habitat richness, and suggests a novel mechanism for species loss events as a result of environmental changes.

Reversible fulminant lactic acidosis and liver failure in an infant with hepatic cytochrome-c oxidase deficiency

Cytochrome-c oxidase (COX) is the most common respiratory chain complex involved in liver failure, either as a single enzyme deficiency or as part of multiple enzyme deficiencies. We describe an infant who presented with fulminant lactic acidosis in the neonatal period. The lactic acidosis resolved spontaneously but liver and pancreatic insufficiency ensued. Isolated cytochrome-c oxidase deficiency was found in liver but not in muscle and fibroblasts. mtDNA rearrangements or depletion were ruled out. By the age of one year, liver and pancreatic functions have normalized completely and neurodevelopment is normal.

Save a child's heart: we can and we should

BACKGROUND

Congenital heart disease (CHD) causes the death of thousands of children in developing countries. At the Wolfson Medical Center (WMC), a prototype program has been developed to address this issue.

METHODS

Since 1996, indigent children have been referred to the program, with the cooperation of partners in developing countries. The project's aims are to (a) train their medical personnel at WMC, (b) travel to participating countries to teach, evaluate patients, operate, and promote the development of local centers, and (c) treat children with CHD, at WMC, who lack a local option for care either due to prohibitive costs or unavailability. The project's personnel are state employees who volunteer to treat additional patients within the framework of their salaries, and community volunteers.

RESULTS

The program has seven partner sites in six countries, including two provinces in China (Hebei and Gansu), Ethiopia, Moldova, Nigeria, the Palestinian Authority, and Tanzania. Five physicians and 10 nurses have been trained from five participating countries. Over the past 4 years, 11 teaching trips have been made abroad, and operations have been performed at four partner sites. A total of 386 patients have been operated on-360 at WMC and 26 at other sites. There have been 17 (4.3%) acute deaths. Follow-up is 92% complete with 3 late deaths reported.

CONCLUSIONS

Hospital-based regional centers can be created to promote the care of children with CHD in developing countries. Good results and follow-up care can be provided with appropriate planning.

Is nebulized aerosol treatment necessary in the pediatric emergency department?

BACKGROUND

Infants and small children admitted to the pediatric emergency department (PED) with acute wheezing episodes (AWE) are currently treated with nebulized wet aerosol (NWA).

OBJECTIVE

To determine the efficacy of MDI with Nebuchamber (Astra AB; Lund, Sweden), a nonelectrostatic spacer device (NESD), as compared to NWA in the treatment of an unselected population of babies and small children with AWE.

DESIGN

Randomized, double-blind, placebo-controlled trial. Forty-two children referred to the PED (median age +/- SD, 16 +/- 15 months) with AWE received either placebo MDI through a NESD (four puffs) and salbutamol 0.5 mL (2.5 mg) as a NWA (group I, n = 19), or salbutamol MDI and 0.5 mL of saline solution administered in the same manner as above (group II, n = 23). This treatment was repeated three times every 20 min.

RESULTS

The respiratory rates (RRs) at baseline were as follows: group I, 45 +/- 11.2 breaths/min; and group II, 52.3 +/- 11.3 breaths/min (p = not significant [NS]). After the first, second, and third interventions, the percent fall from baseline of the RR were as follows: group I, 8.9, 13.1, and 17.9%, respectively; group II, 8. 6, 14.6, and 18.6%, respectively. There was no significant difference at any time in the results between the two groups. The clinical scores (CSs) at baseline were as follows: group I, 6.6 +/- 1.3; group II, 6.8 +/- 1.49 (p = NS). After the first, second, and third interventions, the percent fall from baseline of the CS were as follows: group I, 9.1, 17.9, and 23.2%, respectively; group II, 8. 6, 18.9, and 24.7%, respectively. These results, also, did not differ significantly at any time between the two groups. Hospitalization rate and side effects did not differ between the two groups.

CONCLUSIONS

We conclude that even in the group of unselected very young children (mean age < 2 years) with AWE, the use of MDI with NESD is at least as effective as the use of NWA. As opposed to data from an adult population, no plateau was reached in the dose-response curve using the above doses over time.

Endotracheal tolazoline: pharmacokinetics and pharmacodynamics in dogs

Tolazoline is a potent vasodilator of both arteries and veins and has a powerful effect on the pulmonary vasculature, reducing hypoxic pulmonary vasoconstriction and lowering pulmonary artery pressure. Intravenous tolazoline lowers the mean pulmonary arterial pressure and resistance and increases the cardiac index when given to infants with persistent pulmonary hypertension of the newborn (PPHN). Endotracheally administered tolazoline decreases mean pulmonary arterial pressure and pulmonary vascular resistance, and improves oxygenation without the harmful decline in systemic arterial pressure. The purpose of our study was to examine the pharmacokinetic and pharmacodynamic characteristics of endotracheal tolazoline in order to determine the relationship between endotracheal tolazoline administration, plasma concentration and its effects on the cardiovascular and respiratory systems. Tolazoline was administered endotracheally to 7 newborn dogs, and its serum concentration and the haemodynamic parameters were monitored for 270 min post-delivery. Results are expressed as median and quartiles. It was found that 15 s after dosing, tolazoline plasma concentrations started to increase significantly above baseline levels, reaching a maximum of 2.64 (1.36; 13.16) microg/ml. The extent of tolazoline absorption was 305 (148;453) microg/ min/ml. The volume of distribution was 3.4 (1.6;7.4) 1/kg. The total body clearance was 12.1 (10.9;23.9) ml/min/kg and the elimination half-life was 225 (171;303) min. Endotracheal tolazoline produced an initial short-lived decrease in mean blood pressure in all the dogs, but thereafter the blood pressure increased gradually above baseline levels. Immediately following endotracheal tolazoline significant tachycardia developed, peaking at 90 min. Subsequently, the heart rate gradually decreased and stabilized at values above baseline for 200 min. A single endotracheal dose of tolazoline is effectively absorbed and produces measurable pharmacological effects. Determining the optimal endotracheal dose of tolazoline in the clinical setting requires additional evaluation.

Melatonin receptors in PC3 human prostate tumor cells

Melatonin, secreted nocturnally by the pineal gland, can bind to human benign prostate epithelial cells and attenuate their growth and viability. In the present study, melatonin binding and responses were explored in the human steroid-independent PC3 prostatic tumor cells. PC3 cells bound 125I-melatonin with low affinity (Kd ca. 0.9 nM) at high as well as low cell density. Melatonin enhanced cGMP and 3H-thymidine incorporation at low, but attenuated them at high cell density. In addition, melatonin inhibited cAMP at low, but augmented it at high cell density. These effects were associated with an increase in cell count at low- but not high-density cultures. Pertussis toxin treatment suppressed 125I-melatonin binding and ablated all the effects of melatonin on 3H-thymidine incorporation, cAMP, and cGMP at both cell densities. Cholera toxin treatment failed to block the effects of melatonin on 3H-thymidine incorporation, but prevented the modulation by melatonin of cAMP at low and cGMP at high cell density. The cGMP analog 8-Br-cGMP, inhibited melatonin's effects on 3H-thymidine incorporation at both cell densities. H89, a protein kinase A inhibitor, prevented melatonin's effects on 3H-thymidine incorporation at low but not high cell density. These results provide the first demonstration of direct interaction of melatonin with hormone-insensitive prostate tumor cells. The melatonin receptors in the PC3 cells are coupled to pertussis toxin-sensitive G proteins to induce cell density-dependent changes in cGMP, cAMP, and cell growth.

Salbutamol metered-dose inhaler with spacer for hyperkalemia: how fast? How safe?

OBJECTIVE

To determine the efficacy of inhaled salbutamol (rapidly delivered, using a metered-dose inhaler with a spacer device [MDI-S]) in lowering the serum potassium levels in patients with hyperkalemia.

DESIGN

A randomized, double-blind, placebo-controlled trial.

PATIENTS

Seventeen chronic renal failure patients referred to the Nephrology Unit between October 1, 1997 and March 31, 1998 for hemodialysis were randomized.

INTERVENTION AND RESULTS

Group 1 received salbutamol followed by a placebo. Group 2 received a placebo followed by salbutamol. Each patient inhaled 1,200 microg salbutamol or a placebo through an MDI-S within 2 min. Blood samples were obtained repeatedly before inhalation and after 1, 3, 5, 10, and 60 min. The pulse rate and blood pressure were repeatedly measured. Insulin levels were examined in a subset of patients (n = 10) before, and 1 and 5 min following inhalation. Salbutamol's known side effects, palpitation, tachycardia tremor, and headache, were recorded. Potassium levels rose after 1 min following the completion of treatment and then decreased steadily thereafter. A rise of > or = 0.1 mEq/L was seen in 10 of 17 patients (59%) during the treatment period and there was no change (0%) seen during the placebo period (p < 0.0001). Within 3 min after inhalation of salbutamol, potassium levels declined as a function of time. Potassium levels in those patients taking the placebo did not change as a function of time (p < 0.001). The difference between the placebo and the salbutamol-treated periods reached significance after 5 min (p < 0.05). The serum glucose levels rose following inhalation of salbutamol, with a significant rise after 3 min. The heart rate rose significantly within the first 5 min following inhalation. Serum insulin levels remained unchanged 1 min after inhalation; however, after 5 min, a significant elevation was detected.

CONCLUSION

Salbutamol inhalation of 1,200 microg, using an MDI-S, has a relatively rapid onset of action that induces a consistent reduction in serum potassium levels, starting 3 to 5 min following delivery. Unexpectedly, a paradoxical elevation was detected in serum potassium levels in the first minutes following inhalation. This effect, although minor (0.15 mEq/L above baseline), may cast some doubt on the role of salbutamol inhalation as the first treatment for excessive hyperkalemia.

Melatonin inhibits expression of the inducible isoform of nitric oxide synthase in murine macrophages: role of inhibition of NFkappaB activation

The role of melatonin as an immunomodulator is well established. Recent reports showed that melatonin exerts protective effects in septic and hemorrhagic shock and in inflammation. The expression of the inducible isoform of nitric oxide synthase (iNOS) makes an important contribution to the pathophysiology of shock and inflammation. We studied, in cultured murine macrophages, the role of melatonin in the regulation of the expression of iNOS and defined the mode of melatonin's action. Our results show that melatonin, at 1 microM-1 mM, decreased the production of nitrite/nitrate (the breakdown products of NO) as well as the production of 6-keto-prostaglandin F1alpha (the major stable breakdown product of prostacyclin) in macrophages stimulated with bacterial lipopolysaccharide (10 microg/ml). We observed that melatonin reduces iNOS steady-state mRNA levels and iNOS protein expression in the same concentration range (1 microM-1 mM). Melatonin, up to 10 mM, exerted only a slight direct inhibitory effect on iNOS activity. Using iNOS promoter-luciferase constructs, we found that melatonin inhibits iNOS promoter activation. Inhibition of iNOS expression was associated with inhibition of activation of the transcription factor nuclear factor kappa B (NFkappaB). We conclude that melatonin inhibits NO production in immunostimulated macrophages mainly by inhibiting the expression of iNOS. This is due to inhibition of iNOS transcription, in part through inhibition of NFkappaB activation. Inhibition of iNOS-derived NO production by melatonin may contribute to the anti-inflammatory effects of this pineal secretory product.

Melatonin receptors in benign prostate epithelial cells: evidence for the involvement of cholera and pertussis toxins-sensitive G proteins in their signal transduction pathways

BACKGROUND

Melatonin, the hormone secreted nocturnally by the pineal gland, binds to epithelial cells from the human benign prostate, and can reduce their growth and viability. The possible involvement of GTP binding proteins cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in melatonin responses in these cells were investigated.

METHODS

The effects of melatonin on cAMP and cGMP were assessed in prostate cells untreated or pretreated with pertussis toxin (PTX) or cholera toxin (CTX).

RESULTS

Melatonin augmented cAMP but reduced cGMP in the epithelial cells (maximal responses at 10 nM). The increase in cAMP was attenuated by PTX, but not by CTX, whereas the decrease in cGMP was attenuated by CTX, but not by PTX. CTX, but not PTX, abolished the melatonin-mediated suppression of 3H-thymidine incorporation. In addition, melatonin facilitated the CTX- and PTX-mediated ADP ribosylation of 44- and 41-kilodalton proteins, respectively. The cGMP analogue 8-bromo-cGMP, negated the melatonin-mediated decrease in 3H-thymidine incorporation, whereas H89, a protein kinase A inhibitor, did not inhibit melatonin's effect.

CONCLUSIONS

Melatonin receptors in the human benign prostate epithelial cells enhance cAMP and inhibit cGMP through PTX- and CTX-sensitive G proteins, respectively. The decrease in DNA synthesis may be secondary to the melatonin-mediated decrease in cGMP.

Evidence for a local action of melatonin on the rat prostate

PURPOSE

Melatonin, secreted by the pineal gland at night, inhibits pubertal development in rats and possibly humans. We have recently found functional specific binding sites for 125I-labeled melatonin (125I-melatonin) in human benign prostate tissue, localized in the microsomal fraction of the glandular epithelium. The aim of the present study was to set up an animal (rodent) model for the growth inhibitory effects of melatonin on the prostate.

MATERIALS AND METHODS

Putative melatonin in the rat ventral prostate were explored by means of autoradiography and receptor binding assays and the ability of melatonin to inhibit stimulated prostate growth was tested in vivo.

RESULTS

In vitro autoradiography and equilibrium binding experiments demonstrated specific binding sites for 125I-labeled melatonin (125I-melatonin) associated with the microsomal fraction of the rat ventral prostate cells (apparent dissociation constant 0.9 nM). 125I-melatonin binding was inhibited by 2-iodomelatonin > 6-hydroxy-melatonin > melatonin = N-(2,4 dinitrophenyl)-5-methoxytryptamine whereas similar concentrations of serotonin, 5-methoxytryptamine, and tryptamine were less potent. The guanine nucleotide analogs, guanosine 5'-0-[3-thiotriphosphate] and guanosine 5'-0-[2-thio-diphosphate], inhibited specific 125I-melatonin binding whereas 5'-guanylyl imido-diphosphate was less potent. Daily injections of testosterone to castrated rats induced regrowth of the prostate and increased the weight of the seminal vesicles. Administration of melatonin to the rats through drinking water prevented the testosterone-mediated regrowth of the prostate but had no effect on the seminal vesicles' weight.

CONCLUSIONS

The results demonstrate putative melatonin receptors in the rat prostate and suggest a direct suppression by melatonin of testosterone-dependent prostate growth.

Protective effects of 3-aminobenzamide, an inhibitor of poly (ADP-ribose) synthase in a carrageenan-induced model of local inflammation

A cytotoxic cycle triggered by oxidant-induced DNA single strand breakage and subsequent activation of the nuclear enzyme poly (ADP-ribose) synthetase have been shown to contribute to the cellular injury during various forms of oxidant stress in vitro. The aim of the present study was to investigate the role of poly (ADP-ribose) synthetase in a model of acute local inflammation (carrageenan-induced pleurisy), where oxyradicals, nitric oxide and peroxynitrite are known to play a crucial role in the inflammatory process. The results show that the poly (ADP-ribose) synthetase inhibitor 3-aminobenzamide (given at 1-30 mg/kg) inhibits the inflammatory response (pleural exudate formation, mononuclear cell infiltration, histological injury). Moreover, 3-aminobenzamide reduces the formation of nitrotyrosine, an indicator of the formation of peroxynitrite, in the lung. The present results demonstrate that 3-aminobenzamide, presumably by inhibition of poly (ADP-ribose) synthetase, exerts potent anti-inflammatory effects. Part of the anti-inflammatory effects of 3-aminobenzamide may be related to a reduction of neutrophil recruitment into the inflammatory site.

Inactivation of melatonin receptors by protein kinase C in human prostate epithelial cells

The pineal hormone melatonin regulates seasonal reproduction and pubertal development in mammals. We recently found melatonin receptors in the human benign prostate tissue, primarily associated with the microsome-enriched fraction of the epithelial cells. In cultured benign prostate epithelial cells, melatonin, at physiological concentrations, suppressed [3H]thymidine incorporation and cGMP levels. The effects of melatonin were transient, suggesting inactivation of the receptors. In the present study, the possibility of inactivation of the prostate melatonin receptors by protein kinase C (PKC) was explored. Treatment of the microsome-enriched fraction with crude rat brain PKC in the presence of phorbol 12-myristate 13-acetate (TPA) or CaCl2 abolished the specific [125I]melatonin binding. This effect was prevented by the PKC inhibitor bisindolylmaleimide (GF-109203). [125I]Melatonin binding could be reinstated by iodoacetamide treatment. In benign prostate epithelial cells in culture, TPA pretreatment markedly reduced the apparent affinity of [125I]melatonin binding. In addition, TPA ablated the cells responses to melatonin, namely the suppression of [3H]thymidine incorporation and cGMP levels. Pretreatment with GF-109203 prevented the TPA effects on [125I]melatonin binding and responses. In addition, GF-109203 slowed down the inactivation of the melatonin-mediated inhibition of [3H]thymidine incorporation. Taken together, these data show that melatonin receptors are desensitized by PKC and imply that the transient response to melatonin may be the outcome of a direct or indirect melatonin-mediated activation of endogenous PKC.

Protective effect of melatonin in carrageenan-induced models of local inflammation: relationship to its inhibitory effect on nitric oxide production and its peroxynitrite scavenging activity

In vitro studies have demonstrated that melatonin is a scavenger of oxyradicals and peroxynitrite and an inhibitor of nitric oxide (NO) production. In the present study, we evaluated the effect of melatonin treatment in two models of acute inflammation (carrageenan-induced paw edema and pleurisy), where oxyradicals, NO, and peroxynitrite play a crucial role in the inflammatory process. Our data show that melatonin (given at 62.5 and 125 microg/paw in the paw edema model or 25 and 50 mg/kg in the pleurisy model) inhibits the inflammatory response (paw swelling, pleural exudate formation, mononuclear cell infiltration, and histological injury) in dose-dependent manner in both models. Furthermore, our data suggest that melatonin exerts an inhibitory effect on the expression of the inducible isoform of NO synthase. Melatonin also prevented the formation of nitrotyrosine, an indicator of peroxynitrite, in both models of inflammation. Taken together, the present results demonstrate that melatonin exerts potent antiinflammatory effects. Part of these antiinflammatory effects may be related to an inhibition of the expression of the inducible NO synthase, while another part may be related to oxyradical and peroxynitrite scavenging.

Protection by inhibition of poly (ADP-ribose) synthetase against oxidant injury in cardiac myoblasts In vitro

Peroxynitrite and hydroxyl radical are reactive oxidants produced during myocardial reperfusion injury. In various cell types, including macrophages and smooth muscle cells, peroxynitrite and hydrogen peroxide cause DNA single strand breakage, which triggers the activation of the nuclear enzyme poly (ADP-ribose) synthetase (PARS), resulting in cytotoxicity. Using 3-aminobenzamide and nicotinamide, inhibitors of PARS, we investigated the role of PARS in the pathogenesis of myocardial oxidant injury in H9c2 cardiac myoblasts in vitro. Peroxynitrite (100-1000 microM), hydrogen peroxide (0.3-10 microM) and the NO donor compounds S-nitroso-N-accetyl-DL-penicillamine (SNAP) and diethyltriamine NONOate all caused a dose-dependent reduction of the mitochondrial respiration of the cells, as measured by the mitochondrial-dependent conversion of MTT to formazan. Peroxynitrite and hydrogen peroxide, but not the NO donors caused activation of cellular PARS activity. The suppression of mitochondrial respiration by peroxynitrite and hydrogen peroxide, but not by the NO donors, was ameliorated by pharmacological inhibition of PARS. The protection by the PARS inhibitors diminished at extremely high concentrations of the oxidants. Hypoxia (1 h) followed by reoxygenation (1-24 h) also resulted in a significant activation of PARS, and caused a suppression of mitochondrial respiration, which was prevented by inhibition of PARS. Similar to the results obtained with the pharmacological inhibitors of PARS, a fibroblast cell line which derives from the PARS knockout mouse was protected against the suppression of mitochondrial respiration in response to peroxynitrite and reoxygenation, but not to NO donors, when compared to the result of cells derived from wild-type animals. Based on our data, we suggest that activation of PARS plays a role in the myocardial oxidant injury.

Interplay between sex steroids and melatonin in regulation of human benign prostate epithelial cell growth

Human benign prostatic epithelial cells contain functional melatonin receptors that can suppress cell growth and viability. The development of benign prostatic hyperplasia in men is assumed to result from androgen-estrogen imbalance. The impact of sex steroids on melatonin receptors in human benign prostate epithelial cells was investigated. The suppression by melatonin of [3H]thymidine incorporation and cGMP, and the enhancement of cAMP levels in the cells were used as markers of melatonin responses. Dihydrotestosterone (DHT) and 17 beta-estradiol (E2) separately increased [3H]thymidine incorporation into the cells, but suppressed it when combined. In cells grown with DHT, melatonin responses were extenuated. E2 greatly reduced the apparent affinity of [125I]melatonin binding in these cells without affecting binding site density. In parallel, the ability of melatonin to suppress [3H]thymidine incorporation into the cells was ablated within 1 h after the addition of E2. The melatonin-mediated increase in cAMP and decrease in cGMP concentrations were also ablated by E2. Preincubation of the cells with bis-indolylmaleimide (GF 102903X), a specific inhibitor of protein kinase C, prevented the E2-mediated inactivation of melatonin binding and the inhibitory action on [3H]thymidine incorporation. Prolonged (18-h) incubation of the cells with phorbol 12-myristate 13-acetate to down regulate protein kinase activity, partially restored [125I]melatonin binding and responsiveness in the E2-treated cells. These data indicate that 1) DHT and E2 enhance prostate epithelial cells growth, but reduce cell growth when combined; 2) DHT extenuates the inhibitory effects of melatonin on epithelial cell growth; and 3) E2 acts to inactivate melatonin receptors and consequently responses in human epithelial benign prostatic hyperplasia cells. This process is probably mediated by protein kinase C. Together, these results show an interplay between melatonin and sex steroids in the regulation of benign prostatic epithelial cell growth.

Putative melatonin receptors in the blind mole rat harderian gland

The blind mole rat (Spalax ehrenbergi) displays daily and seasonal rhythms. Melatonin, secreted nocturnally by the pineal gland, is also produced in the harderian gland and affects its morphology in rodents. We report here on the presence of putative melatonin receptors in the blind mole rat harderian gland, located in the microsome-enriched fraction of the cells. Equilibrium 125I-melatonin binding studies indicated high- and low-affinity melatonin binding sites in the female (apparent Kd 10 pM and 2.4 nM, respectively) and low-affinity sites in the male (apparent Kd 2.6 nM) mole rat. The binding sites were not significantly affected by season. Castration increased the density of high-affinity binding sites in males and low-affinity binding in females. 125I-melatonin binding to the gonadectomized mole rat preparation was inhibited by serotonin > 2-iodomelatonin > or = memelatonin > 5-methoxytryptamine. The guanine nucleotide analogs, guanosine 5'-O-[3-thio-triphosphate] and guanosine 5'-O-[2-thio-diphosphate], inhibited specific 125I-melatonin binding, whereas 5'-guanylyl imido-diphosphate was less potent. These results indicate for the first time the presence of GTP-sensitive melatonin binding sites in the blind mole rat harderian gland, and suggest that their expression is under control of sex steroids.

The inhibitory effects of mercaptoalkylguanidines on cyclo-oxygenase activity

1. It has been proposed that in inflammatory conditions, in which both the inducible isoforms of nitric oxide synthase (iNOS) and cyclo-oxygenase (COX-2) are induced, inhibition of NOS also results in inhibition of arachidonic acid metabolism. In the present study we have investigated whether mercaptoalkylguanidines, a novel class of selective iNOS inhibitors, may also influence the activity of cyclo-oxygenase (COX). Therefore, the effect of mercaptoethylguanidine (MEG) and related compounds on the activity of the constitutive (COX-1) and the inducible COX (COX-2) was investigated in cells and in purified enzymes. Aminoguanidine, NG-methyl-L-arginine (L-NMA) and NG-nitro-L-arginine methyl ester (L-NAME) were also studied for comparative purposes. 2. Western blot analysis demonstrated a significant COX-1 activity in unstimulated J774 macrophages and in unstimulated human umbilical vein endothelial cells (HUVEC). Immunostimulation of the J774 macrophages by endotoxin (lipopolysaccharide of E. coli, LPS 10 micrograms ml-1) and interferon gamma (IFN gamma, 100 u ml-1) for 6 h resulted in a significant induction of COX-2, and a down-regulation of COX-1. No COX-2 immunoreactivity was detected in unstimulated HUVEC or unstimulated J774 cells. Therefore, in subsequent studies, the effect of mercaptoalkylguanidines on COX-1 activity was studied in HUVEC stimulated with arachidonic acid for 6 h, and in J774 cells stimulated with arachidonic acid for 30 min. The effect of mercaptoalkylguanidines on COX-2 activity was studied in immunostimulated J774 macrophages, both on prostaglandin production by endogenous sources, and on prostaglandin production in response to exogenous arachidonic acid stimulation. In addition, the effect of mercaptoalkylguanidines on purified COX-1 and COX-2 activities was also studied. 3. In experiments designed to measure COX-1 activity in HUVEC, the cells were stimulated by arachidonic acid (15 microM) for 6 h. This treatment induced a significant production of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha, the stable metabolite of prostacyclin), while nitrite production was undetectable by the Griess reaction. MEG (1 microM to 3 mM) caused a dose-dependent inhibition of the accumulation of 6-keto-PGF1 alpha, with an IC50 of 20 microM. However, aminoguanidine, L-NAME or L-NMA (up to 3 mM) did not affect the production of 6-keto-PGF1 alpha in this experimental system. In experiments designed to measure COX-1 activity in J774.2 macrophages, the cells were stimulated by arachidonic acid (15 microM) for 30 min; this also induced a significant production of 6-keto-PGF1 alpha and MEG (1 microM to 3 mM), aminoguanidine (at 1 and 3 mM), but neither L-NAME nor L-NMA inhibited the production of prostaglandins. 4. In experiments designed to measure prostaglandin production by COX-2 with endogenous arachidonic acid, J774.2 cells were immunostimulated for 6 h in the absence or presence of various inhibitors. In experiments designed to measure prostaglandin production by COX-2 with exogenous arachidonic acid, J774.2 cells were immunostimulated for 6 h, followed by a replacement of the culture medium with fresh medium containing arachidonic acid and various inhibitors. Both of these treatments induced a significant production of 6-keto-PGF1 alpha. Nitrite production, an indicator of NOS activity, was moderately increased after immunostimulation. MEG (1 microM to 3 mM) caused a dose-dependent inhibition of the accumulation of COX metabolites. Similar inhibition of LPS-stimulated 6-keto PGF1 alpha production was shown by other mercaptoalkylguanidines (such as N-methyl-mercaptoethylguanidine, N,N'-dimethyl-mercaptoethylguanidine, S-methyl-mercaptoethylguanidine and guanidino-ethyldisulphide), with IC50 values ranging between 34-55 microM. However, aminoguanidine, L-NAME and L-NMA (up to 3 mM) did not affect the production of prostaglandins.5. In comparative experiments indomethacin, a non selective COX inhibitor, and NS-398, a selective COX-2 inhibitor, reduced (LPS) stimulated 6-keto-PGF1alpha production in J774 macrophages in a dose-dependent manner without affecting nitrite release. Indomethacin, but not NS-398, inhibited 6-keto-PGF1alpha production in the HUVECs. 6.The inhibitory effect of MEG was due to direct inhibition of the catalytic activity of COX as indicated in experiments with purified COX-1 and COX-2. MEG dose-dependently inhibited the purified COX-1 and COX-2 activity with IC50 values of 33microM and 36microM, respectively. Aminoguanidine (at the highest concentrations) inhibited the formation of COX-1 metabolites, without affecting COX-2 activity. High doses of L-NAME (3mM) decreased COX-1 activity only, while L-NMA (up to 3mM) had no effect on the activity of either enzyme. 7.These results suggest that MEG and related compounds are direct inhibitors of the constitutive and the inducible cyclo-oxygenases, in addition to their effects on the inducible NOS. The additional effect of mercaptoalkylguanidines on COX activity may contribute to the beneficial effects of these agents in inflammatory conditions where both iNOS and COX-2 are expressed.

Melatonin is a scavenger of peroxynitrite

Peroxynitrite is a toxic oxidant formed from the reaction of superoxide and nitric oxide under conditions of inflammation and oxidant stress. Here we demonstrate that the pineal neurohormone melatonin inhibits peroxynitrite-mediated oxidant processes. Melatonin caused a dose-dependent inhibition of the oxidation of dihydrorhodamine 123 to rhodamine in vitro. Moreover, in cultured J774 macrophages, melatonin inhibited the development of DNA single strand breakage in response to peroxynitrite and reduced the suppression of mitochondrial respiration. Thus, melatonin appears to be a scavenger of peroxynitrite. This action may contribute to the antioxidant and antiinflammatory effects of melatonin in various pathophysiological conditions.

Functional melatonin receptors in human prostate epithelial cells

Melatonin, secreted nocturnally by the pineal gland, affects gonadal growth and pubertal development in rodents and, presumably, in humans. Recently, we have found, using 125I-labeled melatonin as a probe, specific melatonin binding sites in the human benign prostate tissue; these sites were primarily associated with the microsomal fraction of the epithelial cells. In the present study, we have explored 125I-melatonin binding sites in human benign prostate epithelial cells in culture and investigated the effects of melatonin on growth and viability of these cells. 125I-melatonin bound to the prostate cells with high (K(d) = 68 pM) affinity. Competition experiments revealed that specific binding was inhibited by subnanomolar concentrations of melatonin and 2-iodomelatonin, whereas serotonin and 5-methoxytryptamine reduced the binding only partially. Melatonin (10 pM-10 nM) inhibited the incorporation of 3H-thymidine and 3H-uridine into the prostate epithelial cells in a dose-dependent manner. Inhibition was transient, and the incorporation recovered to control levels within less than 24 h. Protein synthesis as measured by the incorporation of 35S-methionine into cell proteins decayed to minimal levels about 2 h after addition of melatonin, and its recovery was slower compared with that of 3H-thymidine or 3H-uridine incorporation. Melatonin treatment (1 nM) for 2-7 days inhibited cell growth and markedly increased the percentage of non-viable cells in culture, measured by the trypan blue exclusion assay. The results demonstrate high affinity melatonin receptors in the human benign prostate epithelial cells, which may affect cell growth and viability.

Putative melatonin receptors in benign human prostate tissue

Melatonin, secreted by the pineal gland at night, inhibits pubertal development of rats and presumably men. In addition, it may directly suppress prostate growth in the adult rat. To investigate the possibility for a causal relationship between the age-related decline in melatonin production and increase in prevalence of benign prostate hypertrophy (BPH) in man, the presence of melatonin binding sites in human BPH tissue was examined. In vitro autoradiography indicated specific 125I-labeled melatonin (125I-melatonin) binding in the prostate, localized to the glandular epithelium. Separation and subcellular fractionation indicated that these sites were associated with the microsomal fraction of the epithelial cells. Kinetic and equilibrium 125I-melatonin binding experiments revealed that the binding was time dependent and reversible, with an apparent half saturation at 140 pmol/L. Competition experiments indicated high and low affinity melatonin binding sites; binding was inhibited by melatonin (IC50 1 nmol/L and 1 micromol/L, respectively) and partially by the putative melatonin antagonist, N-(2,4 dinitrophenyl)-5-methoxytryptamine (ML-23; IC50 0.1 nmol/L). Serotonin and 6-hydroxymelatonin were less potent, whereas up to 0.1 mmol/Lol/L of 5-methoxytryptamine, 6-methoxymelatonin, and tryptamine caused only a partial reduction in specific binding. The guanine nucleotide analogs, guanosine 5'-O-[3-thiotriphosphate] and guanosine 5'-O-[2-thio-diphosphate, inhibited specific 125I-melatonin binding, whereas 5'-guanylyl imidodiphosphate was less potent. The results indicate putative melatonin receptors in the human prostate epithelium.

High-affinity binding of melatonin to hemoglobin

Determination of melatonin by radioimmunoassay in plasma samples from hemolyzed blood often yields flawed values. We studied the possibility that hemoglobin can bind melatonin and the iodinated tracer 125I-melatonin. The specific binding of 125I-melatonin to purified bovine hemoglobin was found to be rapid, saturable, and reversible (Kd = 315 pM, Bmax = 58 pmol/mg protein) and was inhibited by 2-iodomelatonin, serotonin, melatonin, and 5-methoxytryptamine. These data are compatible with the concept that hemoglobin can interfere with melatonin determinations by competing for melatonin and the iodinated tracer. Unlike melatonin receptor binding, the binding of 125I-melatonin to hemoglobin was not inhibited by guanine nucleotide analogs (i.e., GTP gamma S, GTP beta S, and Gpp(NH)p). Sodium cyanide had no effect on 125I-melatonin binding, indicating that 125I-melatonin does not bind to the heme group. On the other hand, 2,3-bisphosphoglycerate, at physiological concentrations (3-4 mM), decreased the apparent Bmax and Kd of 125I-melatonin binding to hemoglobin. These data suggest that 125I-melatonin binding to hemoglobin is conformation-specific and is unfavorable in the deoxyhemoglobin state. Hemoglobin may serve as a carrier protein for melatonin in the blood and discharge it in the target organs. Subsequently, the efficacy of melatonin's action as a hormone or antioxidant in target tissues may be enhanced.

Plain radiography for diagnosis of gastrointestinal perforation in immune-compromised children--is it enough?

Gastrointestinal perforation is a surgical emergency in the pediatric patient and any delay in diagnosis might be hazardous. In immunocompromised children, the clinical signs of perforation may be blunted. We describe a child with acute lymphoblastic leukemia (ALL) and a perforated appendix and ileum in whom computerized tomography (CT) revealed extraluminal air that was not initially identified on plain abdominal film. Our case demonstrates the importance of early abdominal CT and ultrasound examination in detecting these potentially lethal complications.

Acute acalculous cholecystitis in an infant after cardiac surgery

Acute acalculous cholecystitis is a virulent disease that occurs most commonly in critically ill patients. Imaging studies may facilitate earlier diagnosis and may decrease the morbidity and mortality rates. The authors report on a 30-month-old child with acute acalculous cholecystitis after surgical repair of tetralogy of Fallot. A review of the clinical pathogenesis, diagnosis, and treatment is included.

Effect of heat stress on tonic and GnRH-induced gonadotrophin secretion in relation to concentration of oestradiol in plasma of cyclic cows

Effects of acute and seasonal heat stress on tonic and GnRH-induced LH and FSH secretion were examined during the early follicular phase of the oestrous cycle of cows (n = 40). Prostaglandin F2 alpha was injected on day 11 +/- 1 of the oestrous cycle and on the next day blood samples were collected at intervals of 15-20 min for 14 h, and i.m. injection of GnRH was given after 7 h. Treatments compared were control versus acute heat stress during blood sampling in winter, and cooled versus chronic heat stress in summer. Before GnRH injection, chronic heat stress in summer did not affect basal concentrations of plasma LH, but did lower LH pulse amplitude. However, in cows with low plasma oestradiol (1.9 +/- 0.2 pg ml-1), the mean and basal concentrations and amplitude of tonic LH pulses were reduced by heat stress (3.1, 2.1 and 4.8 versus 1.9, 1.4 and 2.5 ng ml-1, respectively). In cows with high plasma oestradiol (6.3 +/- 0.5 pg ml-1), these parameters were not affected. In chronically heat stressed cows in summer, GnRH-induced increases in plasma LH and FSH concentrations were the same as in the cooled controls. However, in cows with low plasma oestradiol, mean concentrations of FSH in plasma (31.8 versus 25.5 ng ml-1), the peak of the GnRH-induced FSH and LH surge (FSH 47.4 versus 35.6 ng ml-1, LH 50.7 versus 37.3 ng ml-1) and the shape of the GnRH-induced FSH and LH curves (treatment by time interaction) were significantly lower in non-cooled versus cooled controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxytocin and estradiol concentrations in follicular fluid as a means for the classification of large bovine follicles

Large antral follicles (13 to 20 mm in diameter) were collected from ovaries of 109 cows and 17 heifers that also had a regressed corpus luteum at slaughter. Thirty percent of the animals had been injected once with prostaglandin F(2)alpha 48 hours before slaughter. Follicles were divided into 3 groups based on estradiol and oxytocin concentrations in the follicular fluid: Group I follicles, estradiol>/=100 ng/ml and oxytocin<65 pg/ml (preovulatory and assumed pre-gonadotropin surge); Group II follicles, estradiol<100 ng/ml and oxytocin>/=65 pg/ml (preovulatory and assumed post-gonadotropin surge); and Group III follicles, estradiol<100 ng/ml and oxytocin<65 pg/ml (atretic follicles). Treatment with prostaglandin F(2)alpha significantly increased the number of viable granulosa cells and estradiol content in Group I follicles. The estradiol: progesterone ratio was significantly higher in Group I vs Groups II and III, but it was similar for Group II healthy follicles and Group III atretic follicles. To ascertain the classification of follicles, PGF(2)alpha was administered on Day 6 of the cycle to induce corpus luteum regression, and a GnRH analog was administered 24 hours later. At 23 hours after GnRH analog treatment, follicular oxytocin levels significantly rose to 103 pg/ml. Concomitantly, estradiol concentrations fell to below 100 ng/ml. This response was not evident by 13 h after injection of the GnRH analog. The results indicate that follicular estradiol and oxytocin concentrations may be used as a means for the physiological classification of large bovine follicles.

Necrosis and lymphocytic infiltration in choroidal melanomas

Patient survival, tumor lymphocytic infiltration and tumor necrosis were studied and evaluated in 43 enucleated eyes with the same histological diagnosis of spindle 'B' malignant melanoma of the choroid. A significant difference (P less than 0.05) was found between the survival rate of melanoma patients with no evidence of lymphocytic infiltration and/or necrosis in the tumor, compared to those with any evidence of of lymphocytic infiltration and/or tumor necrosis.

Persistently raised intraocular pressure following extracapsular cataract extraction

In this population based study we have reviewed the files of all patients who underwent an extracapsular cataract extraction (ECCE) between 1984 and 1987, were normotensives prior to surgery, and were followed up for at least 10 months after the ECCE. From a total of 1047 operations 746 qualified for the inclusion criteria; of these, 16 (2.1%) were found to have a consistently raised intraocular pressure (greater than 21 mmHg) on more than two occasions) at four months or later after surgery and throughout at least a six-month period. An increased incidence of secondary aphakic glaucoma was associated with anterior chamber IOL implantation (p less than 0.001) and posterior capsule rupture (p less than 0.01), but not with any of the other variables examined (age, sex, surgeon).

Juxtapapillary exophytic retinal capillary hemangioma treated by yellow krypton (568 nm) laser photocoagulation

A 30-year-old man was found to have juxtapapillary exophytic capillary hemangioma complicated by circinate maculopathy and peripapillary exudative retinal detachment. The diagnosis was made from the appearance of the tumor and confirmed by fluorescein angiography. The presence of intermittent hematuria associated with a cystic kidney supported the diagnosis of von- Hippel-Lindau disease. subsequently, and attempt to treat the vascular lesion by yellow krypton (586 nm) laser photocoagulation failed to arrest the progression of the exudative retinal detachment, which finally became total.

'Rush' type retinopathy of prematurity: report of three cases

Three premature infants observed to develop severe stage III retinopathy of prematurity (ROP) at 3 to 5 weeks of age received immediate treatment by cryoablation and photocoagulation, with good results. The critical importance of the ophthalmic examination of premature babies from the age of 2 weeks, so as not to overlook such cases of 'rush' type ROP is stressed and the difficulty involved in treating such small neonates is discussed.

Combined arterial and venous retinal occlusion as a presenting sign of systemic lupus erythematosus

A 22-year-old female was admitted to our department due to sudden loss of vision of her right eye. The funduscopic examination revealed a clinical picture of venous stasis retinopathy combined with macular branch artery occlusion. The physical examination and the laboratory tests confirmed the diagnosis of systemic lupus erythematosus.

An unusual extraocular muscle anomaly in a patient with Crouzon's disease

A 29-year-old female suffering from Crouzon's disease was admitted to hospital with retinal detachment in the right eye. At operation agenesis of 4 extraocular muscles (superior and inferior recti and obliquus) was found, together with abnormal insertion of the 2 horizontal muscles. The same extraocular muscular abnormalities were found in the left eye. We suggest here a new surgical treatment in such cases and discuss the reasons for the limitation of ocular motility in such cases.

Keratopathy associated with hypoparathyroidism and Addison's disease

Two siblings suffering from keratopathy, one with hypoparathyroidism associated with Addison's disease and the other with Addison's disease alone, are described. The hypothesis that there was an autoimmune etiology with variant manifestations in each subject is suggested and discussed.