Ganglion cells from chick retina display multiple functional nAChR subtypes

We have examined the properties of nicotinic acetylcholine receptors in embryonic chick retinal ganglion cells. Ganglion cells, identified according to morphological and physiological criteria, displayed spontaneous or induced action potentials. In 94/99 cells acetylcholine pulses evoked responses. In current clamp mode, acetylcholine provoked membrane depolarization and triggered action potentials. Under voltage clamp conditions, acetylcholine evoked inward currents that were readily blocked by d-tubocurarine. Antagonists specific for homomeric (alpha-bungarotoxin) and heteromeric (dihydro-beta-erythroidine) receptors revealed that ganglion cells express multiple functional receptor subtypes. These findings demonstrate that ACh modulates the electrical activity of these cells and is likely to mediate synaptic transmission. The presence of multiple receptor subtypes may contribute to processing and transmission of information in the retina.

Prevalence and clinical significance of incidental paraprosthetic valvar regurgitation: a prospective study using transoesophageal echocardiography

OBJECTIVE

To assess the prevalence, mechanisms, and significance of paraprosthetic regurgitation detected incidentally by transoesophageal echocardiography (TOE) in patients after heart valve replacement.

DESIGN

Prospective observational study.

SETTING

Tertiary referral centre.

PATIENTS

360 consecutive patients (mean (SD) age 65.8(9.5) years, 193 women) undergoing elective first ever valve replacement.

METHODS

Postoperative and follow up TOE, and tests for haemolysis and anaemia.

RESULTS

There were 243 aortic, 90 mitral, and 27 double valve replacements, using 316 mechanical and 44 tissue valves, giving 270 aortic and 117 mitral valves. One patient with severe paraprosthetic mitral regurgitation underwent immediate reoperation and was excluded from subsequent analyses. Paraprosthetic jets were detected around 16 (6%) of the aortic and 38 (32%) of the mitral valves (p < 0.05) at the postoperative study. Follow up TOE was available for 151 aortic and 67 mitral valves, 0.9 (0.5) years after operation. Paraprosthetic jets were present in 15 (10%) of the aortic and 10 (15%) of the mitral valves (NS). Two thirds of the aortic and a fifth of the mitral jets were new. Paraprosthetic jets were more common in aortic valves in a supra-annular (12 of 88, 14%) than in an intra-annular position (4 or 182, 2%; p < 0.005) and in mitral valves inserted with continuous (36 of 88, 41%) rather than interrupted sutures (2 of 28, 7%; p < 0.001). Lactate dehydrogenase concentration was higher in patients with paraprosthetic jets than in those without (752 (236) v 654 (208) IU/l, p < 0.001). Haemoglobin and haptoglobin concentrations were not different.

CONCLUSIONS

Small paraprosthetic leaks are common, are related to surgical factors, are not associated with increased subclinical haemolysis, and are benign during the first year after heart valve replacement.

Incidence of embolism and paravalvar leak after St Jude Silzone valve implantation: experience from the Cardiff Embolic Risk Factor Study

BACKGROUND

Silver coating of the sewing ring (Silzone) was introduced as a modification of the St Jude Medical standard valve to provide antibacterial protection, but the valve has recently been withdrawn.

OBJECTIVE

To study patients with these prostheses to assess possible adverse effects, and to guide their follow up.

DESIGN

Prospective observational study of risk factors for stroke after valve replacement.

SETTING

Cardiology and cardiac surgery departments in a tertiary centre.

PATIENTS

There were 51 patients with Silzone and 116 with St Jude Medical standard valves. Patients undergoing aortic valve replacement were well matched for stroke risk factors. Silzone patients with mitral valve replacement were younger (mean (SD) age 61 (10) v 66 (7) years), more likely to be female (95% v 65%), and had more pulmonary arterial hypertension (100% v 78%), but fewer coronary artery bypass grafts (5% v 33%) than patients with standard mitral valve replacements (all p < 0.05).

RESULTS

Follow up was 100% in the Silzone group (mean duration 3.0 (0.9) years) and 97.4% in the standard group (4.7 (1.4) years). Survival, morbidity, and anticoagulant control were documented over 682 follow up years (153 for Silzone and 529 for standard). There were six embolic strokes and one peripheral embolism in the Silzone group, all within three months after operation, and five embolic strokes and one peripheral embolism in the standard group. Freedom from major thromboembolism at three months was 65% in the Silzone mitral valve replacement group and 100% in the standard mitral valve replacement group (difference 35%, 95% confidence interval 8% to 62%). There was one reoperation for paravalvar leak in the standard group, but none in the Silzone group (NS). Anticoagulant control in the two groups was similar.

CONCLUSIONS

Patients with Silzone mitral valves had a high rate of early postoperative embolism but no excess paravalvar leak.

Experimental and theoretical study of the photochemical and thermal decomposition of maleic and dichloromaleic anhydrides

The photochemical and thermal behavior of maleic anhydride 1a and dichloromaleic anhydride 1b, in cryogenic matrix were investigated by means of FT-IR spectroscopy. The ketenylcarbenes represent the key intermediate in the decomposition processes of the anhydrides, even if they were not observed experimentally. The yields of the different products depend on the thermal or photochemical reaction conditions. The main photochemical products obtained from 1a were cyclopropenone and acetylene, whereas the major products from 1b were dichlorocyclopropenone and dichloroacetylene, along with small quantities of dichloropropadienone. The thermal reaction leads to dichloro propa dienone, CO, and CO2. MO calculations performed at the HF/6-31G*//HF/6-31G* level support the experimental mechanisms.Key words: photolysis, thermolysis, ab initio calculations, cryogenic matrix, ketenylcarbenes.

Localized pericardial tamponade: difficult echocardiographic diagnosis of a rare complication after cardiac surgery

We report 2 cases of localized pericardial tamponade occurring soon after cardiac surgery, in which the diagnosis could not be made with transthoracic echocardiography. Computed tomography and transesophageal echocardiography, respectively, were necessary, and this underlies the importance of alternative imaging modalities when this condition is suspected. A high index of suspicion is crucial for reaching the correct diagnosis.

Task-related chemical analysis of labial gland volatile secretion in worker honeybees (Apis mellifera ligustica)

Chemical analyses revealed that the labial gland complex of worker honeybees possesses a series of hydrocarbons dominated by odd-numbered carbon chain alkanes along with minor amounts of alkenes and branched alkanes. Foragers contained significantly more secretion than nurse bees. Experiments with bees from colonies induced to have a division of labor independent of age revealed that the differences in the amount of secretion were task, but not age dependent.

The diagnosis of ventilator-associated pneumonia using non-bronchoscopic, non-directed lung lavages

OBJECTIVES

(1)To assess the diagnostic utility of quantitative cultures of non-bronchoscopic lung lavage (NBL) in ventilator-associated pneumonia and evaluate the role of the Bacterial Index; (2) To assess the predictive value of NBL surveillance quantitative cultures in ventilated patients; (3) To evaluate the Clinical Pulmonary Infection Score (CPIS) system in ventilated patients.

DESIGN

A prospective comparison of NBL with bronchoscopic bronchoalveolar lavage and protected specimen brush.

SETTING

Three intensive care units in academic tertiary care centres.

PATIENTS

145 adults ventilated for 72 h, with and without clinical signs of pneumonia.

INTERVENTIONS

Sampling of lower airway secretions by NBL, bronchoalveolar lavage and protected specimen brush.

MAIN OUTCOME MEASURES

Diagnostic reliability of quantitative cultures, Bacterial Index and CPIS.

RESULTS

34 episodes of clinical ventilator-associated pneumonia were documented in 32 patients. 9 episodes were confirmed by concordant blood/pleural culture or post-mortem lung examination. Qualitative concordance of the predominant pathogen between sequential NBL: bronchoalveolar lavage and protected specimen brush was 83 %. Sensitivity and specificity of non-directed bronchial lavage at a threshold of 10(4) CFU/ml were 68 % and 70 % respectively (p = 0. 003) and were comparable with the bronchoscopic methods. However, the low positive predictive value of NBL indicates that quantitation in the absence of clinical signs is unlikely to be useful. Bacterial Index did not improve discriminatory power of quantitation compared with bacterial load of predominant organism. Mean CPIS for confirmed pneumonia cases was 8.4 +/- 1.01, significantly higher than for non-pneumonia observations (p = < 0.0001).

CONCLUSION

NBL is a simple, safe, cheap, readily-available method of diagnosing ventilator-associated pneumonia with comparable diagnostic accuracy to bronchoscopic techniques. Quantitation of respiratory tract cultures can exclude pneumonia in patients with equivocal clinical signs. The diagnostic threshold should vary depending on the length of ventilation, likelihood of pneumonia and antibiotic administration. The Bacterial Index is a flawed mathematical device that has no contributory role in pneumonia diagnosis. The CPIS has some diagnostic role in selected cohorts of ventilated patients.

Evaluation of a protocol to select patients of all ages for cardioversion from atrial fibrillation

OBJECTIVE

to audit the success of a decision protocol to select patients for cardioversion from atrial fibrillation or flutter by recording the success of cardioversion and the maintenance of sinus rhythm over a 2-year period.

DESIGN

retrospective case notes review.

SETTING

a teaching hospital coronary care unit and cardiology department.

PATIENTS

227 consecutive patients were considered for cardioversion from atrial fibrillation or flutter from 1989 to 1992; 128 fulfilled the selection criteria.

MAIN OUTCOME MEASURES

successful cardioversion and maintenance of sinus rhythm after cardioversion.

RESULTS

116 (91%) patients selected by application of the guidelines were successfully cardioverted. The probabilities of maintaining sinus rhythm at 6, 12 and 24 months were 0.92, 0.88 and 0.73 respectively.

CONCLUSION

careful selection of patients in atrial fibrillation identifies a group in whom cardioversion is likely to be safe and successful regardless of age.

Apoptosis induced by beta-N-oxalylamino-L-alanine on a motoneuron hybrid cell line

It has been suggested that beta-N-oxalylamino-L-alanine, a non-protein amino acid present in the Lathyrus Sativus seeds, may play a role in the etiopathogenesis of neurolathyrism, a toxic form of motor neuron disease clinically characterized by a severe spastic paraparesis. In order to investigate the mechanisms of beta-N-oxalylamino-L-alanine-mediated cell death, we studied the effect of this neurotoxin as well as other excitatory amino acids agonists on the growth and survival of motoneuron hybrid ventral spinal cord 4.1 cells. beta-N-oxalylamino-L-alanine was toxic to ventral spinal cord 4.1 cells in a concentration-dependent fashion (0.5-10 mM). Among the excitatory amino acids tested, only glutamate (1-10 mM), quisqualate (1 mM) and, with less extent, beta-N-methylamino-L-alanine (10 mM) induced a significant reduction of cell survival. The effect of Lathyrus Sativus neurotoxin was a slow process, becoming apparent only after 24-48 h of incubation. Interestingly, a mathematical analysis applied to the time course and dose curve of beta-N-oxalylamino-L-alanine toxicity suggested that even for very low concentrations of the amino acid it is theoretically possible to predict a time-dependent effect. The cell death was not blocked by antagonists of N-methyl-D-aspartate or non-N-methyl-D-aspartate receptors; aurintricarboxylic acid and alpha-tocopherol gave a partial protection; cysteine (1 mM) prevented the toxic effect of both Lathyrus Sativus neurotoxin and glutamate as well as quisqualate. Morphologically, in the presence of either beta-N-oxalylamino-L-alanine, glutamate or quisqualate, ventral spinal cord 4.1 cells showed apoptotic features also confirmed by ISEL technique and agarose gel electrophoresis of genomic DNA. Thus, our results suggest that in ventral spinal cord 4.1 motoneuron hybrid cells, in the absence of functional synaptic excitatory amino acid receptors, beta-N-oxalylamino-L-alanine induces cell degeneration through an apoptotic mechanism, possibly mediated by a block of cystine/glutamate Xc antiporter.

[The management of acute complications in gastric cancer]

Forty-five acute complications (perforations and upper digestive hemorrhages) occurring in 650 admitted and operated gastric cancer patients were investigated. Despite all problems raised by these complication (gastric cancer, most commonly in advanced stages and invading the neighboring areas, the poor general condition of the patients, age-related deficiencies), the authors regard the removal of the complicated tumor and sometimes wide gastrectomy (the concomitant resection of gallbladder, spleen, atypical liver resection transverse colon resection) as the only solution for the complications, the postoperative complications and early recurrences of the complications as well as mortality rate being at the same time reduced.

[Splenic hydatid cyst]

The localization of hexacanth embryo at spleen level is quite rare, although, in frequency order, it is the third affected organ after liver and lung. The infestation of the spleen usually takes place by arterial route after the parasite has passed through the two other filters, hepatic and pulmonary. The retrograde venous route, which avoids the liver and lung, is also considered. The diagnosis of splenic echinococcosis is made with the clinical, epidemiological and laboratory findings. The treatment is surgical, consisting, most commonly, in splenectomy; the anastomoses of splenic hydatid cysts with the digestive tube are indicated only in those cases with peculiar evolutive forms; cystotomy, with removal of the content and drainage of the remnant cavity, surgery performed either on abdominal or lumbar route, is the method of choice in the suppurated cysts which fix, by adherences, the spleen to its lodge.

[A giant cancer of a gastric diverticulum]

An observation is presented, of a female patient aged 62 years with a large abdominal tumour. Clinical and para-clinical examinations could not establish the organic origin of the formation. Surgery disclosed a giant tumour developed in a gastric diverticulum situated under the cardia. The patient had suffered for a long time with gastric symptoms and her antecedents included upper digestive haemorrhage which was attributed to gastric ulcer according to radiological examination. In retrospect it was established that the disturbances were determined by a gastric diverticulum, complicated by haemorrhage and which later on had become malignant. In spite of its extraordinarily large size the tumour was removed by total gastric resection, in an attempt to treat radically the cancer.

[A pharmacodynamic investigation of the effect of polyholozidic substances extracted from Plantago sp. on the digestive tract]

From the leaves and seeds of some Plantago species (Plantago major, media, lanceolata) the polyholozidic fraction was separated. A statistically significant gastroprotective action was found both in the case of the polyholozide obtained from seeds and leaves in two experimental models. At higher doses a laxative action was also obtained.

[Voluminous malignant nonsecreting tumors of the adrenal cortex ruptured in thoracic-lumbar injuries]

Based on two cases of nonsecreting malignant adrenal tumors the authors make some clinical and therapeutical considerations. These tumors are rare, have a longer evolution without significant clinical manifestations, may reach considerable size and may become complicated, most frequently by intratumoral hemorrhages and necroses, which usually favour an infection, and more rarely by their rupture. The diagnosis is based on the clinical and laboratory findings. The treatment is surgical, associated with chemotherapy and radiotherapy. The survival interval is long, sometimes exceeding 10 years.

Quantitative determination of rheumatoid factors in serum and synovial liquid of patients with rheumatoid arthritis using lyophilized standard products

The rheumatoid factors constitute one of the major autoantibodies in rheumatoid arthritis (RA). In this study, for the quantitative determination of the RF IgM class, in serum and synovial liquid of patients with RA and JRA, we used the hemagglutination principle and both liquid and lyophilized reagents. The results we obtained demonstrated the superiority regarding the stability, the reproducibility and the possibility of micromethod standardization with lyophilized reagent.