Transcranial Doppler Markers of Diffusion-Perfusion Mismatch

BACKGROUND AND PURPOSE: During the evaluation of acute ischemic stroke with diffusion- and perfusion-weighted magnetic resonance imaging (DWI and PWI, respectively), the presence of salvageable brain tissue is suggested by the occurrence of a perfusion-diffusion "mismatch." DWI and PWI, however, are not universally available and have inherent inconveniences, which justify a search for practical diagnostic alternatives. The purpose of this study is to investigate whether there are transcranial Doppler (TCD) markers of mismatch. METHODS: Retrospective analysis of 22 patients with acute ischemic stroke affecting the middle cerebral artery (MCA) territory, who had a TCD performed within 24 hours of magnetic resonance imaging (MRI) with DWI and PWI. RESULTS: MRI and TCD were performed on average 10.8 +/- 9.2 hours apart. Time from symptom onset to MRI and TCD completion were 1.6 +/- 1.6 and 2 +/- 1.9 days, respectively. MCA and intracranial internal carotid artery (ICA) cerebral blood flow velocity (CBFV) asymmetry, together with a large ICA-to-MCA gradient, were associated with the presence of mismatch. The combined use of 2 TCD parameters (MCA CBFV asymmetry of > or = 30% and ICA-to-MCA gradient > or = 20 cm/sec) had a sensitivity of 75%, specificity of 80%, positive predictive value of 82%, and negative predictive value of 73% at detecting mismatch cases. CONCLUSIONS: Diffusion-perfusion mismatch appears to be associated with interhemispheric asymmetry between MCA and ICA CBFVs, and a large CBFV gradient between the ICA and MCA on the affected side. Prospective studies are required to verify these observations and to determine whether TCD can be used to follow patients with mismatch.     

Cerebral and Systemic Hemodynamics Changes During Upright Tilt in Chronic Fatigue Syndrome

BACKGROUND AND PURPOSE: During head-up tilt (HUT), patients with chronic fatigue syndrome (CFS) have higher rates of neurally mediated hypotension (NMH) and postural tachycardia syndrome (POTS) than healthy controls. The authors studied whether patients with CFS were also more likely to have abnormal cerebral blood flow velocity (CBFV) compared with controls in response to orthostatic stress. METHODS: Transcranial Doppler monitoring of middle cerebral artery (MCA) CBFV was performed during 3-stage HUT prospectively in 26 patients with CFS and 23 healthy controls. At the same time, continuous monitoring of arterial blood pressure (BP), heart rate (HR), endtidal CO2 (ET-CO2) were performed. Results are reported as mean +/- SD. RESULTS: NMH developed in 21 patients with CFS and in 14 controls (P = .22). POTS was present in 9 CFS patients and 7 controls (P = .76). Supine HR was higher in CFS patients, but all other hemodynamics and CBFV measures were similar at baseline. The median time to hypotension did not differ, but the median time to onset of orthostatic symptoms was shorter in those with CFS (P < .001). The CBFV did not differ between groups in the supine posture, at 1 or 5 minutes after upright tilt, at 5 or 1 minute before the end of the test, or at termination of the test. Mean CBFV fell at termination of tilt testing in those with CFS and controls. ET-CO2 was lower at termination of the test in those with CFS versus controls (P = .002). CONCLUSIONS: The results of this study are not consistent with the hypothesis that patients with CFS have a distinctive pattern of MCA CBFV changes in response to orthostatic stress.     

Cervical carcinoma: treatment results and complications of extended- field irradiation

The authors studied treatment complications, recurrence patterns, and survival in 18 patients with histologically proved metastases to the paraaortic lymph nodes from invasive cervical carcinoma treated with extended-field irradiation. Complications following treatment developed in five of 10 patients who underwent transperitoneal nodal biopsy or dissection and in two of eight patients in whom an extraperitoneal approach was used (overall complication rate of 39%); however, only one had a gastrointestinal complication (small bowel obstruction after transperitoneal nodal biopsy and irradiation). Fourteen patients had persistent or recurrent disease within the abdominal or pelvic cavity; only one had distant metastases without recurrence in the abdomen or pelvis. Two of the 14 patients had a recurrence in the surgical scar following extraperitoneal nodal biopsy, possibly due to placement of the scar outside the radiation field. After a minimum follow-up of 48 months, only three of 18 patients (17%) were alive and well.     

Recurrent Streptococcus pneumoniae meningitis in a child with traumatic anterior cranial base defect

Acute bacterial meningitis is a potentially life-threatening infection of the cranial and spinal leptomeninges. Recurrent episodes of meningitis are rarely seen, but when they occur, an extensive investigation has to be made to find out responsible factors. A single episode of acute meningitis may result from bacteriemia, but when followed by recurrent meningitis in pediatric patients, other possible routes of the bacteria invasion to the cerebrospinal fluid (CSF) should be considered. Patients with head injury have the highest risk of acquiring recurrent bacterial meningitis, followed by patients with a congenital anatomic lesion of the skull or duramater, such as meningomyelocele. The underlying cause is a transdural communication between the meningeal space and paranasal sinuses or skin. The first attack of meningitis may occur several weeks to 12 years after the head injury. In addition, recurrent bacterial meningitis may be due to disorders of the immune system, such as complement deficiency. We report a 14-year-old boy, who suffered from recurrent Streptococcus pneumoniae meningitis due to a well-defined defect at the ethmoid roof after a head trauma.     

卡西霉素对血小板在脑微血管内皮细胞粘附的影响及药物的阻断作用

体外实验表明calcimycin0.01μmol·L^-1刺激牛脑微血管内皮细胞25min,使兔血小板与脑微血管内皮细胞的粘附率增高17.1%。PAF受体拮抗剂WEB20860.1,1.0和10.0μumol·L^-1对血小板在脑微血管内皮细胞上粘附的抑制率分别为9.0,22.9和23.1%。DMPP0.1,1.0,10.0μmol·L^-1及Tet0.1,1.0,10。Oμmol·L^-1的抑制率分别为9.7,15.6,22.1%和7.8,15.6及24.6%,提示DMPP和Tet对脑血管有保护作用。     

6-(αα-二苯基乙酰哌嗪基苯基)-4,5-二氢-5-甲基-3(2H)-哒嗪酮对兔血小板聚集及TXB_2,cAMP的影响

6-(αα-二苯基乙酰哌嗪基苯基)-4,5-二氢-5-甲基-3(2H)-哒嗪酮(简称DMDP)是我院新合成的哒嗪酮的衍生物。DMDP可以显著抑制由花生四烯酸(AA(?),ADP和血小板活化因子(PAF)诱导的免血小板聚集,其IC_(50)分别为1.12±0.1.4.19±0.5和2.97±0.1μmol/L。实验还表明DMDP在1～500 μmol/L浓度范围内呈剂量依赖性地抑制兔血小板内血栓素B_2含量,但升高兔血小板内环腺苷酸水平,这可能是其抑制血小板聚集的作用机理之一。     

Hypoglycaemic activity of commelina africana and ageratum conyzoides in relation to their mineral composition

Background

Many plants with antidiabetic properties probably act in part through their content of fibre, vitamins, bioactive or mineral content

Objectives

This study investigated the mineral, proximate, phytochemical compositions and hypoglycaemic effect of Commelina africana and Ageratum conyzoides extracts in diabetic rats, and the likely relationship between this property and the mineral, proximate and phytochemical compositions of the plants.

Methods

The plants were subjected to mineral, proximate composition and phytochemical analysis. Attempt was made to see (if any) the relationship between the hypoglycaemic effect and the mineral, proximate compositions and phytochemistry of the plants. Alloxan-induced diabetic animals were administered 500mg/kg body weight aqueous extracts of the plants and glibenclamide as the reference hypoglycaemic agent.

Results

Aqueous extract of Ageratum conyzoides reduced fasting blood glucose of experimental animals by 39.1% while Commelina africana reduced the same by 78.0%. Alkaloids, cardenolides, saponins, and tannins were detected in both plants. Anthraquinones was absent in C. africana but a trace of it was detected in A. conyzoides. The hypoglycaemic effect of Commelina africana was comparable with the reference hypoglycaemic agent. Ageratum conyzoides showed comparably weaker hypoglycaemic effect than exhibited by reference hypoglycaemic agent. Comparatively, Commelina africana had higher mineral concentrations (except Na) than Ageratum conyzoides.

Conclusions

Plants'' extracts minerals (magnesium, potassium and iron) and bioactive components (alkaloids and cardenolides) seemingly enhanced their hypoglycaemic effect. Furthermore, these minerals, alkaloids and cardenolides could be helpful in ameliorating complications of diabetes like hypertension and cardiovascular disease.