Volume/pressure curve of total respiratory system in paralysed patients: artefacts and correction factors

The volume/pressure (V/P) curve of the total respiratory system in paralysed patients is drawn assuming that volume changes of the respiratory system (V resp) equals volume displacement of the measuring apparatus (V syr), usually a supersyringe. However, in 93 VP curves we found that O₂ removed from the lung-syringe system during the procedure (proportional to the time) largely exceedes the CO₂ added to the lung-syringe system (V gas). This results in a net loss of volume from the system (V resp相似文献   

MR correlates of cerebral atrophy in patients with multiple sclerosis

Objective To investigate the in-vivo correlates of brain atrophy in patients with multiple sclerosis (MS) by assessing the relationship between normalized measures of brain volume (NBV) and other magnetic resonance (MR) measures of tissue damage. Background Brain atrophy diffusely occurs and progressively increases in patients with MS. Nevertheless, the mechanisms leading to brain atrophy in this disease are not fully understood. Methods MR examinations were performed in 20 patients with relapsing-remitting MS. Conventional MRI was used to assess NBV and total brain T2-hyperintense and T1-hypointense lesion volumes. Proton MR spectroscopic imaging and diffusion tensor MR imaging were also performed for large portions of brain containing mainly normal-appearing tissue to provide indices of tissue damage, including N-acetylaspartate to creatine ratio (NAA/Cr) and mean diffusivity (). Results Values of NBV correlated significantly with those of average brain (r = -0.58, p = 0.007) and NAA/Cr (r = 0.67, p < 0.001). The relationship of these markers of tissue damage to NBV was also found when NAA/Cr and were computed together in a composite MR score (r = 0.70, p < 0.001). In contrast, NBV values did not correlate with measurements of average lesion , T₂ and T₁ weighted total brain MRI lesion volumes. Conclusions This study suggests that brain atrophy in MS is not simply due to axonal loss, but rather reflects a more generalized process that involves various brain tissue components. Damage to the normal-appearing tissue rather than the extent and intrinsic pathology of macroscopic lesions seems to be important in the destructive process leading to MS-related irreversible cerebral atrophy. Received: 13 September 2001 Received in revised form: 18 January 2002 Accepted: 4 March 2002     

Pharmacokinetics of Tiaprofenic Acid After Oral Administration in Fasting Patients During and Between Migraine Attacks

This study examined the pharmacokinetics of 300 mg of tiaprofenic acid, a NSAID belonging to the 2-arylpropionic class, as a single oral dose, in 10 migraine patients during and out of migraine attacks. Plasma concentration of tiaprofenic acid was determined by HPLC analysis. Drug absorption appeared to be the same during and out of migraine attacks (absorption half life: during attack, 0.249 +/- 0.122 hr; out of attack, 0.249 +/- 0.105 hr; maximum plasma concentration: during attack, 37.8 +/- 9.8 ug/ml; out of attack, 40.1 +/- 13.2 ug/ml). The other pharmacokinetic parameters evaluated were not affected by headache attacks as well. We conclude that tiaprofenic acid absorption and metabolism are not affected by migraine attacks. Also, our data suggest that tiaprofenic acid might be useful in the treatment of migraine.     

Effect of one-week treatment with vaginal estrogen preparations on serum estrogen levels in postmenopausal women

OBJECTIVE: Approximately 50% of postmenopausal women suffer from vaginal atrophy, and a large proportion of them choose intravaginal estrogen preparations administered for local action to avoid systemic exposure to estrogens and its associated risk of breast and uterine cancer. The primary objective of this study was the evaluation of the systematic bioavailability of estradiol and estrone and the pharmacokinetics of two of the most frequently used intravaginal estrogen preparations, namely Vagifem and Premarin cream. DESIGN: While immunobased assays could not previously provide accurate measurement of serum estrogen concentrations in postmenopausal women, we have used validated mass spectrometry assays to measure the pharmacokinetics of serum estradiol and estrone during the 24 hours following the seventh daily application of 25 microg estradiol (Vagifem) and 1 g (0.625 mg) conjugated estrogens (Premarin) cream in 10 postmenopausal women in each group. RESULTS: Serum estradiol was increased on average by 5.4-fold from 3 to 17 pg/mL during the 24-hour period after daily administration of 25 microg estradiol or 1 g (0.625 mg) conjugated estrogens cream. Serum estrone, conversely, increased 150% with Vagifem and 500% with Premarin cream. CONCLUSIONS: The present data using validated, accurate, and sensitive mass spectrometry assays of estrogens show that the Vagifem pill and Premarin cream, after 1 week of daily treatment, cause an approximately fivefold increase in serum estradiol in postmenopausal women, thus indicating that the effects are unlikely to be limited to the vagina and that systemic actions are expected after application of these intravaginal estrogen preparations.     

Decline of neuroadrenergic bronchial innervation and respiratory function in type 1 diabetes mellitus: a longitudinal study

BACKGROUND AND AIM: Type 1 diabetes mellitus complicated by autonomic neuropathy (AN) is characterized by depressed cholinergic bronchomotor tone and neuroadrenergic denervation of the lung. We explored the effects of AN on the rate of decline of pulmonary sympathetic innervation and respiratory function during a 5-year follow-up. METHODS: Twenty diabetic patients, 11 with AN, were enrolled in 1998 and then followed-up until 2003. During follow-up, glycosylated haemoglobin (HbA1c) was measured every 3 months. In 1998 and 2003 the patients underwent respiratory function tests and a ventilatory scintigraphic study of neuroadrenergic bronchial innervation using 123I-MIBG. RESULTS: During follow-up 4 patients, all with AN, were lost, and 1 developed AN. Forced vital capacity (FVC), and diffusing capacity of the lung for carbon monoxide (DLCO) showed comparable rates of decrease in patients with and without AN. The yearly decline of forced expiratory volume in 1 s (FEV1) was about double the physiologic rate, in both AN and AN-free patients. The MIBG clearance significantly increased both in patients with AN (T1/2: 118.88 +/- 30.14 min at baseline and 92.10 +/- 24.52 min at the end of follow-up) and without AN (135.14 +/- 17.09 min and 92.68 +/- 13.52 min, respectively), indicating a rapidly progressive neuroadrenergic denervation. The rate of the neuroadrenergic denervation was inversely related to the severity of autonomic dysfunction at baseline (Spearman's rho - 0.62, p = 0.017). Neither respiratory function indexes nor MIBG clearance changes correlated with the overall HbA1c values. CONCLUSIONS: Neuroadrenergic denervation of the lung parallels the decline of respiratory function indexes in diabetic patients both with and without AN and seems to be independent from the quality of glycemic control.     

Migraine pain: reflections against vasodilatation

The original Wolff’s vascular theory of migraine was supported by the discovery of a class of drugs, the triptans, developed as a selective cephalic vasoconstrictor agents. Even in the neurovascular hypothesis of Moskowitz, that is the neurogenic inflammation of meningeal vessels provoked by peptides released from trigeminal sensory neurons, the vasodilatation provoked by calcitonin gene-related peptide (CGRP) is considered today much more important than oedema. The role of cephalic vasodilatation as a cause of migraine pain was recently sustained by studies showing the therapeutic effect of CGRP receptor antagonists. We discuss the evidence against vasodilatation as migraine pain generator and some findings which we suggest in support of a central (brain) origin of pain.     

Neuroadrenergic denervation of the lung in type I diabetes mellitus complicated by autonomic neuropathy

STUDY OBJECTIVE: To verify whether autonomic neuropathy (AN) complicating type I, insulin-dependent diabetes mellitus affected neuroadrenergic bronchopulmonary innervation. PATIENTS: Twenty nonsmoking diabetic patients without respiratory diseases were studied: 11 patients with AN (group AN) and 9 patients without AN (control; group C) diagnosed by standardized criteria. DESIGN: Patients underwent respiratory function tests and ventilatory scintigraphies with (123)I-metaiodobenzylguanidine (MIBG) and with (99m)Tc-diethylenetriaminepenta-acetic acid (DTPA) to assess both bronchopulmonary neuroadrenergic innervation and also permeability of the alveolar-capillary barrier to water-soluble tracers. Rates of pulmonary clearance of the two tracers were computed, and correlates were identified by nonparametric statistics. SETTING: University hospital. RESULTS: The AN and C groups had normal respiratory function test results and comparable duration of diabetes and quality of metabolic control. (99m)Tc-DTPA clearance did not distinguish the groups. (123)I-MIBG clearance was faster in the AN group than in the C group (mean +/- SD half-time of the radiotracer time-activity curve [T(1/2)], 116.1 +/- 22.8 min in the AN group vs 139.5 +/- 18.3 min in the C group, p = 0.022), which is consistent with neuroadrenergic denervation in the AN group. (123)I-MIBG clearance was independent from (99m)Tc-DTPA clearance. Faster (123)I-MIBG clearance was significantly associated with worse performance in three of the four autonomic tests. CONCLUSIONS: Neuroadrenergic bronchopulmonary denervation may occur in diabetic patients with AN despite normal clinical and respiratory function findings. Further research is needed to identify clinical and prognostic implications of these findings.     

Use of skin glue versus traditional wound closure methods in brain surgery: A prospective,randomized, controlled study

Traditional skin sutures (TSS) and metal skin clips (SC) are the most common devices utilized for closure of surgical incisions. They are safe and effective, although they require instruments to apply them, are time consuming and, above all, create an extra staff and cost burden for removal of sutures/staples. The ideal incision closure should be simple, effective, safe, rapid, inexpensive, painless, cosmetic and bactericidal. The present study was designed to determine the safety and efficacy of N-butyl octyl cyanoacrylate (NCA) tissue adhesive, a liquid bandage surgical product, for wound closure in brain surgery. Our prospective randomized controlled study compared NCA with traditional methods for wound closure in brain surgery. Over a 6-month period, 40 patients who underwent a supratentorial elective craniotomy were enrolled and randomly allocated into two groups. The 20 participants in group A were treated using a new NCA tissue adhesive while the 20 participants in group B were treated using either nylon monofilament, TSS or SC. In the post-operative period and during follow-up, two different nurses (the second nurse was blinded to the closure method used) recorded details regarding wound aspects, complications and patient satisfaction using a modified version of the Hollander Wound Score Scale. We found no difference in the cosmetic outcome of the two groups, or in wound complications rate, but the patient satisfaction score was higher in group A (9.4 vs. 7.1; p < 0.005). The mean application time of the tissue adhesive was significantly faster than that of the standard suture (115 s vs. 300 s; p < 0.001); in the skin clips subgroup it was 105 s. Our study suggests that the new NCA tissue adhesive is a safe, effective and reliable skin closure for neurosurgical procedures in the supratentorial region; it also achieves optimal cosmetic results, is less time consuming to use and has greater patient satisfaction. However, further studies with a larger number of patients are necessary to corroborate these results.