Initiation of the extrinsic pathway of coagulation by human and rabbit alveolar macrophages: a kinetic study

We examined assembly and expression of the factor X activating complex on human and rabbit alveolar macrophages. Kinetic parameters of the factor X activating reaction were determined by functional titrations of factors VII and X with macrophage tissue factor (TF) added. We found rapid activation of factor X to Xa on alveolar macrophage surfaces. Detection of rapid factor Xa formation on macrophages required addition of exogenous factors VII and X. At plasma concentrations of the purified factors, factor Xa was formed on freshly isolated macrophages at approximately 5.4 pmol/min/10(6) cells. After macrophage maturation in culture for 20 hours with LPS (endotoxin) added, the factor X activation rate was increased two- to sixfold. The km' (apparent km) of TF-factor VII enzymatic complexes assembled on alveolar macrophages for factor X were (258 +/- 55 and 475 +/- 264 nmol/L for human and rabbit cells, respectively). The km' did not change during macrophage maturation in culture, but V'max (apparent Vmax) was consistently increased. The K1/2 of human factor VII (concentrations giving half maximal rates of factor X activation) for the interaction with human and rabbit alveolar macrophage TF were 0.191 +/- 0.096 and 1.7 +/- 0.7 etamol/L, respectively. The K1/2 were not significantly changed after maturation, whereas rates of Xa formation at saturation with factor VII were increased. The fast rates of factor X activation observed at physiologic concentrations of plasma-derived factors VII and X indicate that TF on alveolar macrophages is likely to provide sites for binding of factor VII and activation of factor X in vivo during clotting reactions associated with alveolar edema and inflammation.     

Trends in pemphigus research over 15 years

Background Although pemphigus is a rare autoimmune blistering disease, it attracts the attention of physicians of many disciplines. Objective This study aims to assess the number of articles on pemphigus that have been published over 15 years in dermatology vs. non‐dermatology medical journals, and to evaluate the quality of available evidence. Methods PubMed was searched for articles on pemphigus published between 1 January 1993 to 31 December 2007 using the search word pemphigus. Articles were characterized by publication type and journal type per year. Regression analysis was used to determine the effect of year of publication on number of publications of each type. Results The search yielded 2032 publications on pemphigus during the evaluation period. Sixty‐one per cent were published in dermatology journals. Overall, the number of publications increased linearly with time. Most of this increase was accounted for by publications in non‐dermatology journals. There was an increase in clinical trials over the course of the study period. The number of certain publications with lower quality of evidence, mainly case reports and letters to the editor, increased significantly in the last few years. There was no increase in publications with high quality of evidence. Conclusions The increase on data from non‐dermatology disciplines is a welcome contribution. Nevertheless, high‐quality evidence on pemphigus is still lacking. We trust that the current trend towards evidence‐based dermatology will impact future research on this severe disease.     

Nasal dermoids: the significance of a midline punctum

Nasal dermoids are rare and their diagnosis is often delayed until complications occur. Signs such as a midline nasal punctum may be noted at birth but the significance of this finding frequently passes unrecognised. The cases are reported of two patients which illustrate the typical presentation of these lesions and their subsequent management is discussed.     

Effects of high ambient temperature on parasympathetically mediated cardiovascular reflexes in normal man

AIMS: To examine the effects of high ambient temperature ('heat stressor') on parasympathetically mediated cardiovascular reflexes (power of respiratory sinus dysrhythmia; change in heart rate elicited by change in posture from lying to standing ['30 : 15 ratio']). METHODS: Twelve healthy male volunteers participated in four weekly sessions, each of which was associated with one treatment condition (placebo at an ambient temperature of 22 degrees C; propranolol 40 mg at 22 degrees C; placebo at 40 degrees C; propranolol 40 mg at 40 degrees C), according to a balanced double-blind design. Heart rate was recorded by ECG, finger tremor (7-12 Hz) with an accelerometer strapped to the middle finger of the nondominant hand, and sublingual temperature by a mercury thermometer. Power of finger tremor and the variations of the R-R intervals of the ECG were obtained from Fourier transformations of the data. Data were analysed by analysis of variance, with repeated measures using a significance criterion of P < 0.05; individual comparisons of active treatment with placebo and of data obtained at 40 degrees C with those obtained at 22 degrees C were made with Fisher's Least Significant Difference test. RESULTS: Heart rate was increased by the heat stressor, and this increase was abolished by propranolol. The heat stressor reduced the power of respiratory sinus dysrhythmia and the 30 : 15 ratio, and increased the power of physiological finger tremor. Propranolol did not affect heat stressor-induced changes in the parasympathetic cardiac reflexes, but reduced the heat stressor-induced enhancement of finger tremor. CONCLUSIONS: The increase in the power of physiological finger tremor at high ambient temperature is consistent with sympathetic activation, whereas the reduction in the power of respiratory sinus dysrhythmia and 30 : 15 ratio indicates a decrease in parasympathetic activity. These results demonstrate that high ambient temperature may induce vagal withdrawal in the heart.     

Cavernous hemangioma of the parietal bone. A case report

Intraosseous cavernous hemangiomas are a rare finding in the calvarium. It is a benign tumors arising from the intrinsic vasculature of the bone. We report one case observed in a 31 year-old female, presented with a progressive left parietal mass. A plain X-ray of the skull and cranial CT-scan showed a osteolytic lesion in the left parietal bone. Surgery consisted of total resection of the lesion and cranioplasty. The postoperative course was uneventful. Histological study revealed a cavernous hemangioma of the diploe. In view of this observation and the literature review, clinical; radiological and therapeutic aspect of this rare entity are discussed.     

Benign fronto-orbital osteoblastoma arising from the orbital roof: case report and literature review

BACKGROUND: Osteoblastoma is an uncommon benign osteogenic neoplasm that rarely involves the orbit. Intracranial and intraorbital extension causing neurologic and ophthalmologic symptoms and signs is very unusual. We report the case of an osteoblastoma of the orbital cavity with ethmoidal and anterior cranial fossa extension presenting as unilateral proptosis. Manifestations and management of this rare fronto-orbital lesion are discussed, and the relevant literature is reviewed. CASE DESCRIPTION: This 22-year-old man experienced a 3-month history of progressive left proptosis without neurologic symptoms. Computed tomography and magnetic resonance imaging scans demonstrated a bony mass involving the roof of the left orbit and extending laterally to the adjacent ethmoid cells and upward to the lower part of the homolateral frontal convexity without parenchymal abnormality. A presumptive diagnosis of osteoma was considered. A left fronto-orbital craniotomy was performed. At surgery, the tumor was well circumscribed by a sclerotic margin. It was granular with bony spicules, destroying the orbital roof and involving the orbital cavity, ethmoidal cells, and anterior cranial fossa. The lesion was totally removed, and the anterior cranial base reconstructed. The histologic features were typical of benign osteoblastoma. After a follow-up period of 12 months, the patient has remained well without evidence of recurrence. CONCLUSION: Osteoblastoma should be considered in the differential diagnosis with other fronto-orbital bone-forming lesions. Although generally regarded as benign, a complete resection is recommended to prevent the possibility of postoperative recurrence and malignant transformation. Twelve previously reported cases were also reviewed.