A glutamate concentration-biased allosteric modulator potentiates NMDA-induced ion influx in neurons

Precisely controlled synaptic glutamate concentration is essential for the normal function of the N-methyl D-aspartate (NMDA) receptors. Atypical fluctuations in synaptic glutamate homeostasis lead to aberrant NMDA receptor activity that results in the pathogenesis of neurological and psychiatric disorders. Therefore, glutamate concentration-dependent NMDA receptor modulators would be clinically useful agents with fewer on-target adverse effects. In the present study, we have characterized a novel compound (CNS4) that potentiates NMDA receptor currents based on glutamate concentration. This compound alters glutamate potency and exhibits no voltage-dependent effect. Patch-clamp electrophysiology recordings confirmed agonist concentration-dependent changes in maximum inducible currents. Dynamic Ca2+ and Na+ imaging assays using rat brain cortical, striatal and cerebellar neurons revealed CNS4 potentiated ion influx through native NMDA receptor activity. Overall, CNS4 is novel in chemical structure, mechanism of action and agonist concentration-biased allosteric modulatory effect. This compound or its future analogs will serve as useful candidates to develop drug-like compounds for the treatment of treatment-resistant schizophrenia and major depression disorders associated with hypoglutamatergic neurotransmission.

Expandable metal stents for the palliation of malignant gastroduodenal obstruction

PURPOSE

Gastric outlet obstruction is a debilitating complication of upper gastrointestinal malignancy. We present our experience with insertion of self-expanding metal stents (SEMS).

METHODS

Twenty-eight patients were referred, stenting being attempted in 23. Two patients had esophageal Wallstents inserted through a gastrostomy; 21 had an endoscopic approach with enteral Wallstents.

RESULTS

One stent insertion failed, ten patients (45%) returned to a normal diet, ten patients (45%) managed semi-solid food and two patients (9%) had no significant improvement. No immediate complications were seen. One patient subsequently developed pancreatitis. Reintervention (4 stents, 1 jejunostomy, 1 gastrojejunostomy) was required in six of 22 patients (27%) for inadequate stent expansion (1), second stricture (2), stent migration (1), and tumor ingrowth (2). The mean survival was 95.4 days (SD 78.8 days, range 3-230 days). The mean follow-up time was 98.9 days (SD 86.7 days, range 3-309 days).

CONCLUSIONS

SEMS are effective in palliating malignant gastric outlet obstruction. A combined endoscopic/fluoroscopic approach allows the most complete assessment of the stricture and removes the need for gastrostomy insertion. Careful assessment of the gastrointestinal tract distal to the lesion is important.

Variability in measurement of internal carotid artery stenosis by arch angiography and duplex ultrasonography--time for a reappraisal?

OBJECTIVES

to determine the inter- and intra-observer variability of ICA stenosis measurement using duplex, ECST and NASCET methods.

DESIGN

a retrospective review of arch angiograms and carotid duplex scans in 50 patients.

MATERIALS AND METHODS

carotid stenoses were calculated by three independent observers according to NASCET and ECST methods. Variation between observers for NASCET and ECST was determined. For each observer, the variation between NASCET and ECST was determined. The variation between duplex and both NASCET and ECST was determined.

RESULTS

inter-observer agreement on the degree of ICA stenosis was clinically and statistically good for NASCET but was poorer for ECST. For each observer, comparison between NASCET and ECST showed 95% limits of agreement of around 50 percentage points. Comparison of duplex with NASCET and ECST showed similar 95% limits of agreement.

CONCLUSIONS

arch angiography allows reproducible measurement of carotid stenosis by the NASCET method between different observers. For the ECST method, reproducibility is not so good. Variations in results between NASCET and ECST and between angiography and duplex are significant. In view of the similar results of the NASCET and ECST trials, this suggests that degree of stenosis may only be a surrogate marker for outcome following carotid endarterectomy.

Early mobilization following angioplasty

AIM

To assess the incidence of puncture site complications in in-patients undergoing early mobilization following angioplasty with a view to performing day case angioplasty.

MATERIALS AND METHODS

One hundred and twenty-eight patients undergoing peripheral and renal angioplasty using a sheath size of up to 6 French were recruited prospectively. The mobilization protocol consisted of supine bed rest for 2 h, followed by gradual mobilization, so that the patient was ambulant 4 h after the procedure. Mobilization was delayed if clinically appropriate. Puncture sites were scored for discomfort, paraesthesia, visible bruising and palpable haematoma after groin compression and the following morning.

RESULTS

One hundred and forty-four puncture sites were studied. There were 44 haematomas in total, of which 37 (26%) were less than 2.5 cm and seven (4.9%) were between 2.5 cm and 7.5 cm. Four patients (2.8%) had visible bruising greater than 7.5 cm. No patient assessed discomfort higher than moderate at any stage. Mobilization was delayed in 15 patients. In 11 this was due to puncture site oozing, haematoma in one, two were hypertensive and one required surgery for limb ischaemia. All complications occurred within 4 h of angioplasty. No patient required surgery or transfusion for haemorrhagic complications.

CONCLUSION

Mobilization at 4 h was successful in 90% of cases but 10% require more prolonged bed rest. No delayed complications occurred. These results suggest that day case angioplasty is feasible in most cases.Butterfield, J. S. (2000). Clinical Radiology55, 874-877

A comparison of bolus chasing and static digital subtraction arteriography in peripheral vascular disease

The purpose of this study was to compare the techniques of bolus chasing angiography (BCA) and digital subtraction angiography (DSA). 75 patients with symptomatic atherosclerotic peripheral vascular disease were randomly assigned to have their lower limbs examined by BCA or DSA. Dose-area product (DAP), time of examination and dose of contrast medium were measured. Staff doses were measured with personal electronic dosemeters. Image quality was assessed from the laser printed images. DSA produced better images of vessels below the inguinal ligament, particularly the crural vessels (1/76 vs 17/74 non-diagnostic examinations, p < 0.00001) but at a higher DAP (median 53.8 Gy cm2 vs 18.9 Gy cm2, p < 0.01). Contrast medium dose was higher with BCA (29.8 gI2 vs 25.3 gI2, p < 0.01). Staff doses per unit patient dose were 2.3-3.3 times higher with BCA than DSA. Because of the poor long-term prognosis of patients with peripheral vascular disease, the improved image quality obtained by DSA justifies the increased radiation dose.

Technique for providing analgesia during percutaneous biliary interventional procedures

AIMS

To evaluate the efficacy of interpleural analgesia during percutaneous transhepatic biliary procedures.

METHOD

With the patient lying in the left lateral decubitus position a right sided interpleural catheter was sited at a chosen point between the 6th and 9th interspaces. Lignocaine was injected to provide a splanchnic and intercostal nerve block. The technique of interpleural block (IPB) is described. Assessment of the pulse, BP and O(2)saturation during the subsequent biliary procedure was made. The patient evaluated the maximum degree of pain felt during the biliary procedure according to a four-point pain scale (0-3). The nurse and radiologist also gave an objective assessment of the pain score.

RESULTS

An IP catheter was successfully placed in 22 patients, one patient having the IPB on two occasions. Siting of the IP catheter failed in three patients. Good analgesia with no requirement for further analgesia or sedation was achieved in 11 patients on 12 occasions. Seven patients required additional small doses of analgesia for mild pain during the biliary procedure. IPB failed in four patients who required additional analgesia and sedation. No complication of the IPB technique occurred in our patient group.

CONCLUSION

IPB is a safe and relatively effective method for analgesia during transhepatic percutaneous biliary procedures.

Self-expanding oesophageal metal stents for the palliation of dysphagia due to extrinsic compression

The role of self-expanding metallic stents is well established in the palliation of oesophageal stenosis and dysphagia due to primary oesophageal malignancy. However, their role in palliation of dysphagia due to external compressive mediastinal malignancies is not well established. The purpose of this study was to assess the efficacy of self-expanding metallic stents in the palliation of dysphagia due to extrinsic oesophageal compression by mediastinal malignancy. Between January 1995 and January 1998, 21 patients with oesophageal compression due to malignant mediastinal tumours underwent oesophageal stent placement for palliation of dysphagia. Complete data were available in 17 patients (10 men and 7 women). The mean age was 63.5 years (range 46-89 years). A total of 19 stents were placed successfully. The dysphagia grade prior to and after oesophageal stent placement was assessed and the complications documented. Of the 17 patients, 16 reported an improvement in dysphagia. The mean dysphagia score improved from 3.1 prior to treatment to 1.3 after treatment. In 1 patient the stent slipped during placement and another stent was placed satisfactorily. Early complications (within 48 h) in the form of mild to moderate retrosternal chest pain occurred in 5 patients. This was treated symptomatically. Late complications (after 48 h) in the form of bolus impaction occurred in 2 patients. This was successfully treated with oesophagoscopy and removal of bolus. In 2 patients the stent was overgrown by tumour and in one of these an additional stent was placed. In 1 patient incomplete closure of a tracheo-oesophageal fistula was observed. There was no procedure- or stent-related mortality. The mean survival time of this group was 2. 1 months. Self-expanding metallic stents can be safely and effectively used in the palliation of dysphagia due to external mediastinal malignancies.

Abdominopelvic CT scan findings after surgery for ovarian cancer

AIMS

To evaluate abdomino-pelvic changes in patients who had total abdominal hysterectomy (TAH) and bilateral salpingo-oophorectomy (BSO) for stage I ovarian cancer.

METHOD

The postoperative computed tomographic (CT) scans of 23 patients who had undergone TAH and BSO for stage I ovarian tumours between 3 and 14 weeks previously were assessed, providing there had been no treatment with chemotherapy or radiotherapy and that each patient had normal tumour marker (CA125) levels after surgery. After the CT scan patients were followed up and had no clinical or biochemical (CA125) evidence of relapse for a median of 27 months (range 11 to 78 months). The following sites were assessed by two observers: the vaginal vault, round ligaments, bladder, rectum, perirectal fat, pelvic sidewalls, omentum, surgical scar and abdominal wall. Any abnormality was recorded, with re-evaluation on follow-up CT scans in ten patients (between three and 17 months).

RESULTS

The following abnormalities were seen: (1) Thickened round ligaments (n=12) with bulbous masses at the surgically transected ends (n=7). This was bilateral in eight patients. (2) Vaginal vault thickening (n=11) either uniform (n=6) or bulbous bilaterally (n=2) or unilaterally (n=3). (3) Subtle omental bed stranding or nodularity (n=11). (4) Peritoneal thickening underlying the scar (n=4). (5) Asymmetrical rectus abdominis muscles (n=3) adjacent to the surgical scar or thickened scar tissue in the anterior abdominal wall (n=4). No significant bladder, rectal, perirectal or nodal abnormalities were found.

CONCLUSION

Pseudotumours at the transected ends of the round ligaments, or uniformly swollen round ligaments, may be identified in patients who have had TAH and BSO, as may vaginal vault thickening. Other changes which may be observed in the abdomen and pelvis are peritoneal thickening adjacent to the scar and omental bed stranding.

The effects of CV205-502 in patients with hyperprolactinaemia intolerant and/or resistant to bromocriptine

CV205-502 is a new non-ergot dopamine agonist currently being studied for the treatment of hyperprolactinaemia. We have assessed the effects of CV205-502 on prolactin secretion and the clinical consequences of hyperprolactinaemia in 16 patients with hyperprolactinaemia who had previously been unsuccessfully treated with bromocriptine. These patients had been either intolerant of and/or resistant to the effects of bromocriptine. Sixteen patients, all women in an age range between 20 and 49 years (mean 31.5 years), were treated for periods of between 8 and 52 weeks with doses of CV205-502 ranging from 0.075 to 0.3 mg taken once daily at night. Seven out of 10 of the patients, who were intolerant of bromocriptine, tolerated CV205-502 better with fewer side effects although the nature of the side effects was similar to that associated with bromocriptine. Only 1 patient from this group stopped taking CV205-502 due to side effects. Six of 11 patients exhibiting bromocriptine resistance showed a significant reduction in the degree of hyperprolactinaemia but normoprolactinaemia was achieved in only 1. Galactorrhoea ceased in 2 of 6 patients, menstruation resumed in 6 of 11 patients presenting with amenorrhoea, and 2 patients conceived. In patients with bromocriptine intolerance and/or resistance, CV205-502 is useful as a second line treatment.