Second international guidelines for the diagnosis and management of hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease with an estimated prevalence of 1 in 5000 that is characterized by the presence of vascular malformations (VMs). These result in chronic bleeding, acute hemorrhage, and complications from shunting through VMs. The goal of the Second International HHT Guidelines process was to develop evidence-based consensus guidelines for the management and prevention of HHT-related symptoms and complications. The guidelines were developed using the AGREE II (Appraisal of Guidelines for Research and Evaluation II) framework and GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. The guidelines expert panel included expert physicians (clinical and genetic) in HHT from 15 countries, guidelines methodologists, health care workers, health care administrators, patient advocacy representatives, and persons with HHT. During the preconference process, the expert panel generated clinically relevant questions in 6 priority topic areas. A systematic literature search was done in June 2019, and articles meeting a priori criteria were included to generate evidence tables, which were used as the basis for recommendation development. The expert panel subsequently convened during a guidelines conference to conduct a structured consensus process, during which recommendations reaching at least 80% consensus were discussed and approved. The expert panel generated and approved 6 new recommendations for each of the following 6 priority topic areas: epistaxis, gastrointestinal bleeding, anemia and iron deficiency, liver VMs, pediatric care, and pregnancy and delivery (36 total). The recommendations highlight new evidence in existing topics from the first International HHT Guidelines and provide guidance in 3 new areas: anemia, pediatrics, and pregnancy and delivery. These recommendations should facilitate implementation of key components of HHT care into clinical practice.

Dynamic regulation of spinal pro-inflammatory cytokine release in the rat in vivo following peripheral nerve injury.

Spinal release of cytokines may play a critical role in the maladapted nociceptive signaling underlying chronic pain states. In order to investigate this biology, we have developed a novel 'high flux' intrathecal microdialysis approach in combination with multiplex bead-based immunoassay technology to concurrently monitor the spinal release of interleukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF)alpha in rats with unilateral sciatic nerve chronic constriction injury (CCI). Intrathecal microdialysis was performed under isoflurane/N(2)O anaesthesia in rats with confirmed mechanical hypersensitivity. In a first study, C-fiber strength electrical stimulation of the operated nerve in neuropathic rats was found to evoke a dramatic increase in IL-1beta efflux ( approximately 15-fold) that was significantly greater than that observed in the sham-operated group. Spinal IL-6 efflux was also responsive to primary afferent stimulation, whereas TNFalpha was not. In a second study, treatment with the glial inhibitor propentofylline for 7days normalized CCI-induced mechanical hypersensitivity. In the same animals, this treatment also significantly reduced intrathecal IL-1beta, IL-6 and TNFalpha and prevented afferent stimulation-evoked cytokine release of both IL-1beta and IL-6. These results provide support for glia as the source of the majority of intrathecal IL-1beta, IL-6 and TNFalpha that accompanies mechanical hypersensitivity in the CCI rat. Moreover, our studies demonstrate the ability of a neurone-glia signaling mechanism to dynamically modulate this release and support a role of spinal IL-1beta in the phasic transmission of abnormal pain signals.

GABA transporter type 1 (GAT-1) uptake inhibition reduces stimulated aspartate and glutamate release in the dorsal spinal cord in vivo via different GABAergic mechanisms.

Mechanisms through which the reported antinociceptive activity of GABA re-uptake inhibitors is mediated (and where on the sensory neuraxis) have not been defined. Here, microdialysis in the anaesthetised rat was used to examine the effect of selective GABA transporter type 1 (GAT-1) inhibition on basal and evoked amino acid release in the dorsal spinal cord. Reverse dialysis of the selective GAT-1 inhibitor NO-711 (10-300microM) induced a concentration-related increase in extracellular GABA (maximal approximately threefold of basal levels) without affecting other amino acids. Employing an S2/S1 paradigm, release evoked by brief high (45mM) K(+)-induced depolarisation of aspartate and glutamate, but not GABA or glycine, was found to be significantly reduced by reverse dialysis of NO-711 (300microM). Co-administration of selective antagonists for GABA(A) or GABA(B) receptors ((+)-bicuculline (100microM) or SCH 50911 (100microM), respectively) prevented the GAT-1 inhibition-induced reduction of evoked aspartate. In contrast, while (+)-bicuculline also antagonised the reduction of evoked glutamate, SCH 50911 (up to 1mM) was without effect. Inhibition of GAT-1 re-uptake was further found to play a permissive role in autoinhibitory effects on GABA release mediated through GABA(A) and GABA(B) receptors. These data demonstrate that augmentation of GABAergic neurotransmission by re-uptake inhibition activates pharmacologically distinguishable inhibitory influences on aspartate and glutamate release in the dorsal spinal cord. Thus, inhibition of spinal pro-nociceptive neurotransmitter release may contribute to the analgesic action of this drug class.

Monolithic column-based reversed-phase liquid chromatography separation for amino acid assay in microdialysates and cerebral spinal fluid.

The development of a HPLC method using a monolithic C18 column is described using fluorescence detection for the assay of 21 amino acids and related substances with derivatisation using ortho-phthaldialdehyde (OPA) in the presence of 3-mercaptopropionic acid (3-MPA). The method employs a tertiary gradient and has a run time of 24 min. Linearity (r2) for each amino acid was found to be greater than 0.99 up to a 10 microM concentration; reproducibility across all analyses (relative standard deviation (R.S.D.)) was between 0.97 and 6.7% and limit of detection (LOD) between 30 and 300 fmol on column. This method has been applied to the analysis of amino acids in both spinal microdialysis and cerebral spinal fluid samples.

Selective serotonin re-uptake inhibition attenuates evoked glutamate release in the dorsal horn of the anaesthetised rat in vivo.

Augmentation of serotonergic neurotransmission at the level of the dorsal spinal cord is proposed to contribute to the analgesic activity of selective serotonin (5-HT) reuptake inhibitors (SSRIs). In this study we have utilised microdialysis perfusion to determine the effect of two structurally unrelated SSRIs on depolarisation-induced aspartate and glutamate release in the dorsal spinal cord of the anaesthetised rat. Perfusion with artificial extracellular fluid containing 45 mM potassium produced a significant increase in aspartate and glutamate efflux. Sensitivity, at least in part, to antagonism of calcium entry by high extracellular Mg2+ indicated a neuronal origin for a proportion of stimulated release. Reverse dialysis of paroxetine (1-30 microM) reduced the increase in glutamate in a concentration dependent manner, with a significant reduction evident following inclusion in the perfusate of 30 microM. Administration of an equi-potent dose of citalopram (300 micoM) also reduced depolarisation induced glutamate release. Aspartate levels tended to decrease in the presence of paroxetine and citalopram, but this trend did not reach significance. Co-perfusion of paroxetine (30 microM) with the selective 5-HT(1A) receptor antagonist WAY 100635 (100 microM) did not prevent the reduction in depolarisation induced glutamate efflux. These results demonstrate that local administration of SSRIs has an inhibitory influence on evoked release of glutamate in the dorsal horn. This could indicate regulation of excitatory neurotransmission mediated through augmented serotonergic neurotransmission and activation of a serotonergic receptor other than the 1A subtype. Alternatively, direct inhibition with voltage dependent calcium channels, potentially a property intrinsic to molecules with high selectivity for the 5-HT transporter, may underlie this effect.

Positive N-methyl-D-aspartate receptor modulation by selective glycine transporter-1 inhibition in the rat dorsal spinal cord in vivo.

In this study we have employed the selective glycine transporter-1 (GlyT-1) and GlyT-2 transporter inhibitors R-(-)-N-methyl-N-[3-[(4-trifluoromethyl)phenoxy]-3-phenyl-propyl]glycine (1:1) lithium salt (Org 24598) and 4-benzyloxy-3,5-dimethoxy-N-[1-(dimethylaminocyclopently)methyl]benzamide (Org 25543), respectively, and microdialysis perfusion to determine the effect of GlyT transporter inhibition on extracellular amino acid concentrations in the lumbar dorsal spinal cord of the halothane-anaesthetised rat. Reverse dialysis of Org 24598 (0.1-10 microM) induced a concentration-related increase in extracellular glycine accompanied by a progressive increase in citrulline, but not aspartate, glutamate or GABA, efflux. Org 25543 (10 microM) by the same route induced a similar increase in glycine levels without affecting the efflux of other amino acids quantified. To test the hypothesis that the increase in citrulline efflux resulted from activation of the N-methyl-D-aspartate receptor (NMDA-R)/nitric oxide synthase (NOS) signalling cascade, the sensitivity was determined of GlyT-1 inhibition-induced effects to NMDA-R antagonism or NOS inhibition. Co-administration by reverse dialysis of the selective NMDA-R channel blocker MK-801 (0.5 mM) or the selective antagonist of the strychnine-insensitive glycine site, 7-chlorokynurenic acid (1 mM), with Org 24598 (10 microM) did not affect the uptake inhibition-induced increase in glycine efflux, but did significantly attenuate the increase in extracellular citrulline. Similarly, co-administration with Org 24598 of the isoform non-selective and selective neuronal NOS inhibitors Nomega-nitro-L-arginine methyl ester (1 mM) or 1-(2-trifluoromethylphenyl)imidazole (0.2 mM), respectively, prevented Org 24598-induced citrulline efflux with no effect on increased glycine efflux. These data provide evidence that the observed increased in extracellular citrulline is a consequence of positive modulation of NMDA-R, secondary to increased extracellular glycine and support a protective role for GlyT-1 against fluctuations in extracellular glycine uptake at glutamatergic synapses in the dorsal spinal cord. Such a mechanism could be important to NMDA-R-mediated synaptic plasticity in the spinal cord and be of relevance to the clinical usage of GlyT-1 inhibitors.

Halothane anesthesia affects NMDA-stimulated cholinergic and GABAergic modulation of striatal dopamine efflux and metabolism in the rat in vivo.

Microdialysis of the striatum of halothane-anesthetized rats was used to study the participation of local cholinergic and GABAergic neurotransmission in NMDA receptor-modulated striatal dopamine release and metabolism. Reverse dialysis.of NMDA (1 mM) evoked a 10-fold increase in dopamine efflux and reduced DOPAC and HVA to > 20% of basal values. The effect of NMDA on dopamine efflux was abolished by atropine (10 microM) but unaffected by (+)-bicuculline (50 microM). NMDA-induced decrease in DOPAC (but not HVA) efflux was potentiated by atropine, whereas (+)-bicuculline attenuated the decrease in DOPAC and HVA. Compared to our previous studies in unanesthetised rats, our data suggest that halothane anesthesia alters the balance between NMDA-stimulated cholinergic and GABAergic influences on striatal dopamine release and metabolism. Differential sensitivity to halothane of NMDA receptors expressed by the neurones mediating these modulatory influences, or loss of specific NMDA receptor populations through voltage-dependent Mg2+ block under anesthesia, could underlie these observations.

Squamous cell carcinoma of the eyelids.

AIM: To review the clinical features, management, and outcomes of surgical treatment of eyelid squamous cell carcinoma (SCC). METHODS: A retrospective review of all eyelid SCCs treated between 1992 and 2001. RESULTS: 51 cases were identified in 50 patients. Patient ages ranged from 26 to 93 years, with a mean age of 65 years. 33 patients were male and 17 were female. The lesion was found on the lower lid in 31 cases, upper lid in five cases, lateral canthus in six cases, and medial canthus in nine cases. Perineural invasion was found in four patients, and orbital invasion in three patients. Recurrence occurred in one patient. Treatment was by complete excision with histological confirmation of clear margins. Exenteration was required in three patients. No patients developed lymph node or distant metastases. One patient, who declined treatment, died as a result of the tumour. Mean follow up was 31.1 months. CONCLUSIONS: Eyelid SCC is a relatively uncommon, but potentially fatal disease. However, if detected early and treated adequately, the prognosis is generally excellent. Treatment by complete excision with histological confirmation of tumour clearance is recommended. Perineural spread is an adverse prognostic sign, which may require postoperative radiotherapy. Orbital invasion is a rare complication but, if recognised early, can be treated effectively with exenteration. Because presentation varies and histological examination is required for accurate diagnosis, any suspicious lesion occurring on the eyelids should be excised or biopsied. All patients with eyelid SCC should be advised of the risk of recurrent or new tumours and encouraged to attend lifelong follow up. Prevention remains of prime importance in minimising the morbidity and mortality of these lesions.

Involvement of intrinsic cholinergic and GABAergic innervation in the effect of NMDA on striatal dopamine efflux and metabolism as assessed by microdialysis studies in freely moving rats.

Microdialysis perfusion was used to study the participation of striatal cholinergic and gamma-aminobutyric acid-ergic (GABAergic) neurotransmission in basal and N-methyl-D-aspartate (NMDA) receptor-modulated dopamine release and metabolism in the striatum of the freely moving rat. Reverse dialysis of atropine (1-50 microM) induced a concentration-related increase in dopamine efflux and decrease in 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) efflux. (+)-Bicuculline (10-100 microM) similarly increased dopamine efflux, but was without consistent effect on metabolite efflux. Reverse dialysis of NMDA (1 mM) evoked an approximately twofold increase in dopamine efflux and decreased DOPAC and HVA efflux to 30-40% of basal levels. The effect of NMDA on dopamine efflux was completely abolished by coadministration of tetrodotoxin (TTX; 1 microM) or atropine (10 microM), and markedly potentiated (approximately fourfold) by coadministration of (+)-bicuculline (50 microM). The NMDA-induced decrease in dopamine metabolite efflux was inhibited by coadministration of TTX or (+)-bicuculline, but was unaffected by atropine. Our data suggest that dopamine release in the striatum is subject to both cholinergic and GABAergic tonic inhibitory mechanisms mediated through muscarinic and GABAA receptors, respectively. Furthermore, NMDA-stimulated dopamine release also involves obligatory cholinergic facilitation and an inhibitory GABAergic component mediated through these respective receptors.

Eccrine poroma of the eyelid.

A clinicopathological case report of a 71-year-old Caucasoid man with an unusual right lower eyelid lesion, which proved to be an eccrine poroma, is presented. Benign eccrine poromas have not previously been reported to occur on the eyelid. Compete surgical excision of this lesion proved to be curative, with no recurrence after 3 years follow up. Eccrine poromas are common benign tumours of the intraepidermal sweat duct unit. Sweat glands occur commonly on the eyelids and eccrine poroma should be considered in the differential diagnosis of eyelid tumours.

Determination of the extracellular concentration of glycine in the rat spinal cord dorsal horn by quantitative microdialysis.

Two quantitative microdialysis methods were used to determine the extracellular concentration of glycine in the dorsal spinal cord of halothane-anaesthetised rats. Extracellular glycine determined by zero net flux was 2.6+/-0.3 microM and by the zero flow method was 3.3+/-0.3 microM. For comparison the glycine content of cerebrospinal fluid was determined to be 6.4+/-1.1 microM. There was no correlation between the extracellular and the cerebrospinal fluid concentrations.

Clinicopathological report Periocular tumour of the follicular infundibulum.

Tumour of the follicular infundibulum (TFI) is an uncommon, benign lesion of the skin adnexae. Four cases are reported of periocular TFI. In all cases a clinical diagnosis of basal cell carcinoma was made before surgery; however, histopatholog ca examination revealed TFI. This is an epithelial tumour showing differentiation along the lines of the follicular infundibulum. Characteristic features are a shelf-like proliferat on of pale epithelia cells in the upper dermis, attachment to the epidermis and the upper portions of the pilosebaceous units, a dense border of elastic fibres, and palisading of the peripheral cell layer of the tumour plate. This benign tumour has not, to the authors' knowledge, been reported in the ophthalmic literature. It has a non-specific appearance and may be clinically misdiagnosed as naevus sebaceous, xanthoma, seborrhoeic keratosis, or basal cell carcinoma.

Dermatomyofibroma: a report of two cases, one occurring in a child.

Dermatomyofibroma is a recently described plaque-like dermal tumour composed of myofibroblasts that usually presents around the shoulder, axilla and posterior neck, often in young adult females. Here, we present two cases, one from the posterior axilla of a 33-year-old female and one from the posterior neck of a 7-year-old male. Both were clinically red-brown lesions with histological and immunohistochemical features diagnostic of dermatomyofibroma. There was no evidence of aggressive biologic behaviour with 3 months and 2 months follow up, respectively. While the majority of dermatomyofibromas present in postpubescent females, the 7-year-old male exemplifies a subgroup occurring in male children which appears to show a particular predilection for the posterior neck.

Inhibition of nitric oxide synthase by 1-(2-trifluoromethylphenyl) imidazole (TRIM) in vitro: antinociceptive and cardiovascular effects.

1. The ability of a range of substituted imidazole compounds to inhibit mouse cerebellar neuronal nitric oxide synthase (nNOS), bovine aortic endothelial NOS (eNOS) and inducible NOS (iNOS) from lungs of endotoxin-pretreated rats was investigated. In each case the substrate (L-arginine) concentration employed was 120 nM. 2. 1-(2-Trifluoromethylphenyl) imidazole (TRIM) was a relatively potent inhibitor of nNOS and iNOS (IC50S of 28.2 microM and 27.0 microM respectively) but was a relatively weak inhibitor of eNOS (IC50, 1057.5 microM). The parent compound, imidazole, was a weak inhibitor of all three NOS isoforms (IC50S: nNOS, 290.6 microM; eNOS, 101.3 microM; iNOS, 616.0 microM). Substitution of imidazole with a phenyl group to yield I-phenylimidazole (PI) resulted in an isoform non-selective increase in inhibitory potency (IC50S: nNOS, 72.1 microM; eNOS, 86.9 microM; iNOS, 53.9 microM). Further substitution of the attached phenyl group resulted in an increase in nNOS and a decrease in eNOS inhibitory potency as in TRIM, 1-chlorophenylimidazole (CPI; IC50S: nNOS, 43.4 microM; eNOS, 392.3 microM; iNOS, 786.5 microM) and 1-(2,3,5,6-tetrafluorophenyl) imidazole (TETRA-FPI; IC50S; nNOS, 56.3 microM; eNOS, 559.6 microM; iNOS, 202.4 microM). 3. The ability of TRIM to inhibit mouse cerebellar nNOS activity in vitro was influenced by the concentration of L-arginine (0.12-10.0 microM) in the incubation medium. When mouse cerebellar nNOS was used as enzyme source a double reciprocal (Lineweaver-Burk) plot in the presence/absence of TRIM (50 microM) revealed a competitive inhibitory profile. The K(m) for L-arginine and the Ki for TRIM calculated from these data were 2.4 microM and 21.7 microM, respectively. The ability of TRIM to inhibit mouse cerebellar nNOS activity in vitro was unaffected by varying the time of exposure of the enzyme to TRIM from 0-60 min at 0 degree C. 4. TRIM exhibits potent antinociceptive activity in the mouse as evidenced by inhibition of acetic acid induced abdominal constrictions. The ED50 for TRIM following i.p. administration was 20 mg kg-1 (94.5 mumol kg-1). The antinociceptive effect of TRIM was reversed by pretreatment of animals with L-arginine (50 mg kg-1, i.p.) and was not accompanied by sedation, motor ataxia or behavioural changes (rearing, crossing, circling, dipping) as assessed by use of a box maze procedure. 5. L-NG nitro arginine methyl ester (L-NAME, 20 mg kg-1, i.v.) but not TRIM (0.5-20 mg kg-1, i.v.) increased mean arterial blood pressure (MAP) in the urethane-anaesthetized rat. 6. L-NAME (100 microM) potentiated the contractile response of the rabbit isolated aorta to phenylephrine (ED50; 0.084 +/- 0.01 microM in the presence and 0.25 +/- 0.05 microM in the absence of L-NAME; maximum response, 7.7 +/- 0.4 g in the presence and 5.6 +/- 0.5 g in the absence of L-NAME, n = 6, (P < 0.05) whilst TRIM (1-100 microM) was without effect. L-NAME (100 microM) but not TRIM (1-100 microM) also reduced carbachol-induced relaxation of the phenylephrine-precontracted rabbit aorta preparation. 7. L-NAME (50 microM) potentiated the vasoconstrictor effect of bolus-injected noradrenaline (10-1000 nmol) and reduced the vasodilator effect of carbachol (10 microM) added to the Krebs reservoir in the rat perfused mesentery preparation. L-NAME (50 microM) also reduced nitric oxide (NO) release (measured by chemiluminescence of nitrite in the Krebs perfusate) in response to noradrenaline (100 nmol; 53.8 +/- 4.0 pmol ml-1 in the presence and 84.8 +/- 8.0 pmol ml-1 in the absence of L-NAME, n = 15, P < 0.05) and carbachol (10 microM; 63.9 +/- 5.0 pmol ml-1 in the presence and 154.0 +/- 9.0 pmol ml-1 in the absence of L-NAME, n = 15, P < 0.05). TRIM (50 microM) did not affect either the vasoconstrictor response to noradrenaline or the vasodilator response to carbachol or the accompanying release of NO from the perfused rat mesentery.

The antinociceptive effect of 1-(2-trifluoromethylphenyl) imidazole (TRIM), a potent inhibitor of neuronal nitric oxide synthase in vitro, in the mouse.

1-(2-trifluoromethylphenyl)imidazole (TRIM) is a potent inhibitor of neuronal (mouse cerebellar) and inducible (lung from endotoxin-pretreated rats) isoforms of nitric oxide synthase (NOS) with IC50 values of 28.2 microM and 27.0 microM, respectively. In contrast, TRIM is a poor inhibitor of bovine aortic endothelial NOS with an IC50 of 1057.5 microM. TRIM (10-50 mg kg-1) administered i.p. exhibits dose-related antinociceptive activity in the mouse (assessed as inhibition of late phase formalin-induced hindpaw licking behaviour) with an ED50 of 85.8 mumol kg-1. In contrast, TRIM (50 mg kg-1, i.p.) failed to influence mean arterial blood pressure in the urethane-anaesthetized mouse. Thus, TRIM may be of use as an experimental tool with which to investigate the biological roles of nitric oxide (NO) within the central nervous system.