An in vitro investigation of the action of lamotrigine on neuronal voltage-activated sodium channels

Lamotrigine (LTG), 6-(2,3-dichlorophenyl)-1,2,4-triazine-3,5-diamine, is a novel antiepieptic drug structurally unrelated to the major anticonvulsants in current use. Previous studies of LTG in rodents revealed efficacy in maximal electroshock test, pentylenetetrazol test and kindling models of seizures suggesting potential utility in the treatment of partial and generalized (tonic-clonic) seizures. In the present study, LTG was found to block sustained repetitive firing of sodium-dependent action potentials in mouse spinal cord cultured neurons and inhibit [3H]batrachotoxinin A 20-alpha-benzoate binding in rat brain synaptosomes suggesting a direct interaction with voltage-activated sodium channels.

Thermal dye measurements of extravascular lung water in critically ill patients. Intravascular Starling forces and extravascular lung water in the adult respiratory distress syndrome

To assess the concurrent influence on extravascular lung water (EVLW) content of the intravascular Starling forces, the pulmonary capillary wedge pressure (PCWP), and the colloid osmotic pressure (COP), we measured EVLW by the thermal green dye technique in 174 patients with and without radiographically defined pulmonary edema; in the former group, patients with cardiac (CPE) and noncardiac (NCPE) causes of pulmonary edema were compared (study A). In 119 patients, EVLW was again measured one to three days later (study B). Patients with CPE demonstrated a significantly lower EVLW (9.3 +/- 3.9 ml/kg) (mean +/- SD) than patients with NCPE (14.5 +/- 4.9 ml/kg; p less than 0.05), despite a higher mean PCWP in the former group (20 +/- 7 mm Hg) than in the latter (12 +/- 6 mm Hg; p less than 0.05). In patients potentially with only a hydrostatic cause of pulmonary edema in study A, regression analysis demonstrated the following: EVLW = 3.2 + 0.30 PCWP (r2 = 0.38; p less than 0.005); and in patients with NCPE, EVLW = 10.9 + 0.304 PCWP (r2 = 0.17; p less than 0.01). In study B the change (delta) in EVLW between the two studies was described as follows: delta EVLW = 0.25 + 0.173 delta PCWP (p less than 0.01) + 0.663 group NCPE (p, not significant) + 0.236 group NCPE X delta PCWP (p less than 0.01). This latter equation indicated that the EVLW content manifested a greater change with concurrent alterations in the PCWP in patients with NCPE than was found in patients with only a hydrostatic influence to EVLW formation. Therefore, NCPE is characterized by a greater measurable thermal green dye EVLW than is observed in CPE at any given PCWP, and the PCWP synergistically influences EVLW accumulation in both CPE and NCPE.

On the preservation of syntax in Alzheimer's disease. Evidence from written sentences

We examined the syntactic complexity of single written sentences elicited from 368 adults undergoing examination for possible Alzheimer's disease. The clause length and composition of the sentences varied with the severity of dementia. The nondemented adults' sentences contained more propositions, main and secondary verbs, and conjunctions than those produced by the mildly and moderately demented adults. Sentence length in clauses, propositional content, and the use of conjunctions and main and secondary verbs discriminated among stages of the severity of the disease. The present results suggest that, while dementia severity affects written linguistic output, such output is, nonetheless, grammatic and coherent.

Sonographic, magnetic resonance imaging, and mammographic assessments of preoperative size of breast cancer

High resolution sonographic (39 cases), magnetic resonance imaging (32 cases), and mammographic (35 cases) measurements of preoperative size of breast cancer were correlated with the pathologic size in 39 patients with breast carcinoma to determine the most accurate imaging technique for breast cancer size. There were nine T1, 21 T2, four T3, and four T4 tumors. Sonographic and magnetic resonance imaging measurements of tumor size demonstrated correlation coefficients of 0.92 and 0.93, respectively, both of which were superior to that of mammography (0.84). Sonographic tumor size evaluation thus is shown to be equivalent to magnetic resonance imaging in this study. Three of nine (33%), four of seven (57%), and four of eight (50%) T1 tumors would have been overstaged by ultrasonography, magnetic resonance imaging, and mammography, respectively. Three of 21 (14.3%), one of 16 (6.3%), and two of 18 (11.1%) T2 tumors would have been understaged by ultrasonography, magnetic resonance imaging, and mammography, respectively. We therefore found ultrasonography to be of value in the diagnosis and staging of breast cancer.

The development of phonological awareness: effects of spoken language experience and orthography

Phonological awareness, the ability to analyze spoken language into small sound units, has been shown to be affected by the individual's early orthographic experience (alphabetic vs. non-alphabetic). Past studies, however, have not differentiated the effect of script alphabeticity from that of spoken language experience, which covaries strongly with the phonological properties of the language. The present study compares younger, pre-reading to older, literate children from different linguistic backgrounds on their phonological awareness. Hong Kong and Guangzhou subjects both spoke Cantonese. The latter subjects had early experience with Pinyin (alphabetic) in addition to their logographic Chinese reading; the former read only logographic Chinese. New Zealand subjects spoke English and read the Roman alphabet. Results showed that: (1) the Hong Kong and Guangzhou pre-readers performed very similarly at all levels of phonological awareness; (2) the New Zealand pre-readers outperformed their Hong Kong and Guangzhou counterparts on onset, rime, and coda analyses; (3) the Guangzhou reading children outperformed their Hong Kong counterparts on onset and coda analyses. Whereas finding (3) reflects an effect of alphabeticity in the first learned script, finding (2) in combination with finding (1) indicates an effect of early spoken language experience independent of orthography. The fact that orthographic and spoken language experience both impact on the development of phonological skills implies a mediating function of phonological awareness in integrating sound information derived from reading and perceiving speech.

Constituents of Dipterocarpaceae Resins. IV. Triterpenes of Shorea acuminata and S. resina-nigra

Application of N.M.R. methyl resonance data led to revision of the structures given to the two cis 2,3-diols resulting from osmium tetroxide oxidation of methyl oleana-2,12-dien-28-oate (10). 2α,3α-Dihydroxyolean-l2-en-28-oic acid (6a), a new natural product, occurs in Shorea acuminata resin. Other constituents are 2α-hydroxy-ursolic acid (14a), mangiferonic acid (15b), and asiatic acid (14c). S. resina-nigra contains β-amyrin (16a), ursolaldehyde (14f), and Ψ-taraxesterol(17a).

Safety and efficacy of pharmacological thromboprophylaxis for hospitalized patients with cirrhosis: a single-center retrospective cohort study

BACKGROUND

Hospitalized patients with cirrhosis are at increased risk for venous thromboembolism (VTE). The benefits and risks of pharmacological thromboprohylaxis in these patients have not been well studied.

OBJECTIVES

To examine the safety and efficacy of pharmacological VTE prophylaxis in hospitalized cirrhotic patients.

PATIENTS/METHODS

Retrospective cohort study of patients with cirrhosis hospitalized at an academic tertiary care referral center over a 5-year period.

RESULTS

Six hundred hospital admissions accounting for 402 patients were included. VTE prophylaxis was administered during 296 (49%) admissions. Patients receiving VTE prophylaxis were older (59 years vs. 55 years, P < 0.001), had longer lengths of stay (9.6 days vs. 6.8 days, P = 0.002), and lower Model for End-Stage Liver Disease scores (13.2 vs. 16.1, P < 0.001). In-hospital bleeding events (8.1% vs. 5.5%, P = 0.258), gastrointestinal bleeding events (3.0% vs. 3.2% P = 0.52), new VTE events (2.37% vs. 1.65%, P = 0.537), and mortality (8.4% vs. 7.3%, P = 0.599) were similar in the two groups. VTE prophylaxis did not reduce the risk of VTE (odds ratio 0.94, 95% confidence interval 0.23-3.71), and patients receiving unfractionated heparin, but not low molecular weight heparin, were at increased risk for in-hospital bleeding events (odds ratio 2.38, 95% confidence interval 1.15-4.94 vs. 0.87, 0.37-2.05, respectively).

CONCLUSION

The rate of VTE in this cohort of hospitalized cirrhotic patients was low and was unaffected by pharmacological thromboprophylaxis. Unfractionated heparin was associated with an increased risk for in-hospital bleeding, suggesting that if thromboprophylaxis is indicated, low molecular weight heparin may be favored.

Effects of Perinatal Exposure to Ketamine on the Developing Brain

Initially used as an analgesic and anesthetic, ketamine has unfortunately been abused as a popular recreational party drug due to its psychotropic effects. Over the last decade, ketamine has also emerged as an effective rapid-onset anti-depressant. The increasingly widespread use and misuse of the drug in infants and pregnant women has posed a concern about the neurotoxicity of ketamine to the immature brains of developing fetuses and children. In this review, we summarize recent research findings on major possible mechanisms of perinatal ketamine-induced neurotoxicity. We also briefly summarize the neuroprotective effects of ketamine in the presence of noxious stimuli. Future actions include implementation of more drug abuse education and prevention campaigns to raise the public’s awareness of the harmful effects of ketamine abuse; further investigations to justify the clinical use of ketamine as analgesic, anesthetic and anti-depressant; and further studies to develop alternatives to ketamine or treatments that can alleviate the detrimental effects of ketamine use, especially in infants and pregnant women.

Ibuprofen reduces the progression of permeability edema in an animal model of hyperdynamic sepsis

Since severity of acute lung injury (ALI) is reduced by pretreatment with non-steroidal agents, we hypothesized that ibuprofen would ameliorate ALI when administered after the onset of septic lung injury. Twenty-four hours after cecal ligation and perforation (CLP) in 23 sheep during a 4 h study period (period S), pulmonary lymph flow (QL) increased 16.2 +/- 12.1 ml/min (P less than 0.01) from base line, whereas lymph-to-plasma total protein concentration ratios ([L/P]TP) remained unchanged. During the subsequent 24 h of study (period D), 10 sheep received parenteral ibuprofen, 12.5 mg/kg every 6 h, and 13 sheep served as untreated septic controls. Throughout period D, a progressive increase in QL (16.2 +/- 16.3 ml/60 min) from period S was greater in the untreated than in the ibuprofen (2.5 +/- 9.0 ml/60 min, P less than 0.02) group. Between base line and period D, increase in lung wet-to-dry weight ratios was greater in the untreated group than in the ibuprofen group (P less than 0.05). Concurrently mean pulmonary arterial pressure increased 4.7 +/- 7.3 mmHg in the untreated group (P less than 0.05) during period D vs. 0.0 +/- 5.2 mmHg in the ibuprofen group (NS). When administered after septic ALI had been established by CLP, ibuprofen reduced an otherwise progressive increase in both fluid flux and extravascular lung water.

Unusual origins of the buccal and mylohyoid nerves

Dissection of the mandibular nerve in a cadaver of southern Chinese origin showed the mylohyoid nerve arising from the lingual nerve and the buccal nerve arising from the inferior alveolar nerve within the mandibular ramus. It is estimated that this variation in the origin of the buccal nerve occurs in 6.1% of the southern Chinese population.

Right and left ventricular performance in acute hypoxemic respiratory failure

We examined biventricular performance on two occasions in 28 patients with acute hypoxemic respiratory failure (ARF), using a combination of invasively determined pressures and flows as well as radionuclide scintigraphy to measure the right and left ventricular ejection fractions (RVEF and LVEF, respectively). From the EF and concurrently measured thermodilution stroke volumes, we calculated right and left ventricular end-diastolic and end-systolic volume indices (EDVI and ESVI, respectively). Regression analysis demonstrated that changes (delta) in global right ventricular function (RVEF) were inversely correlated with concurrent changes in the mean pulmonary arterial pressure (MPAP): delta RVEF = 0.015-0.015 delta MPAP (r2 = 0.60; p less than .005), while an increase in right ventricular preload (RVEDVI) was positively correlated with changes in MPAP: delta RVEDVI = 2.68 +/- 6.27 delta MPAP (r2 = 0.46; p less than .005). Global left ventricular function (LVEF) was related to changes in systemic pressures as well as to right-sided events: delta LVEF = -0.01-0.0015(delta RVESVI) + 0.001(delta BP systolic)-0.42(CVP/RVEDVI) (r2 = 0.35; p less than .01). These data confirm the significant influence of right ventricular afterload on RVEF in ARF patients and an apparent interrelationship between altered right ventricular systolic function and global left ventricular performance.

The imaging diagnosis of hepatic schistosomiasis japonicum sequelae

We reviewed the ultrasound (US) and computed tomography (CT) examinations of the liver in 21 patients with hepatic schistosomiasis japonicum (HSJ), to assess the role of imaging in its diagnosis. Thirteen patients had histopathological evidence of hepatic ova deposition. A 'network' pattern was present in 14 of 17 (82%) patients on US, and 'turtle-back' calcification in 11 of 13 (85%) patients on non-contrast CT (NCCT). The combination of US and NCCT was positive for HSJ in all nine patients subjected to both investigations. These findings are specific for HSJ and we discuss how they differ from the imaging findings reported in hepatic Schistosoma mansoni (HSM). We conclude that the sequelae of HSJ infection create an imaging diagnosis. Although an uncommon incidental finding at liver imaging, the combined US and CT appearances are so characteristic that in the majority of patients biopsy can potentially be avoided.

Remacemide HCl and its metabolite, FPL 12495AA, limit action potential firing frequency and block NMDA responses of mouse spinal cord neurons in cell culture

The novel anticonvulsant, remacemide HCl [(+/-)-2-amino-N-(1-methyl-1,2-diphenylethyl)acetamide monohydrochloride; FPL12924AA], and a desglycinated metabolite [(+/-)-1-methyl-1,2-diphenylethylamine monohydrochloride; FPL 12495AA] reversibly limited sustained high-frequency repetitive firing (SRF) of sodium-dependent action potentials by mouse spinal cord neurons in monolayer dissociated cell culture. Limitation occurred with an IC50 of 7.9 X 10(-6) M for remacemide and 1.2 X 10(-6) M for FPL 12495AA (P < 0.05 vs. remacemide). Stereoisomers of the desglycinate limited SRF with IC50 values of 3.3 X 10(-6) M and 3.5 X 10(-6) M for the S(+) and R(-) compounds, respectively. The concentration of racemic desglycinate and of either stereoisomer that produced limitation in all neurons tested was 10(-4) M. Maximal rate of rise (Vmax) of action potentials decreased progressively until firing ceased during 400-ms depolarizing pulses. Efficacy of remacemide, but not of the desglycinate, increased with time (maximum at 16-36 h). The limitation was voltage dependent. In addition, reduction of Vmax and action potential failure occurred during stimulation with 400-ms pulses and trains of brief (1 ms) depolarizations at different frequencies. These findings suggest an effect on voltage-sensitive sodium current that generates the action potential upstroke. Remacemide and the desglycinate also significantly reduced the amplitude of neuronal responses to pressure application of NMDA in use-dependent manner at concentrations equal to the IC50 values for limitation of action potential firing. Resting potential and input resistance were not changed significantly by either drug. Limitation of high-frequency firing of action potentials by both remacemide HCl and FPL 12495AA may contribute to the anticonvulsant efficacy of these compounds at concentrations overlapping the range required to block glutamatergic hyperexcitability.

Rabbit synoviocyte inositol phospholipid metabolism is stimulated by hydroxyapatite crystals

Inhibition of prostaglandin E2 synthesis partially ameliorates some aspects of synovitis, but joint destruction still progresses. Other aspects of phospholipid metabolism may play a role in synovial tissue pathophysiology. Products of phosphatidylinositol metabolism can activate intracellular processes in response to extracellular stimuli. We asked whether this pathway is activated in synoviocytes in monolayer tissue culture by the addition of hydroxyapatite (HA) crystals in medium. These crystals are found in pathological human synovial fluid. These crystals are associated with the secretion of degradative enzymes and with a destructive arthritis in humans. Rabbit synoviocyte cultures, previously incubated with [3H]inositol to label inositol phospholipids, were stimulated with the addition of hydroxyapatite (180 micrograms/ml) to the cultures. There was enhanced intracellular accumulation of [3H]inositol monophosphate (30-100%) after 4 h. This indicated an increased phospholipase C activity. The radioactivity in [3H]inositol bis- and trisphosphates was too low to reliably measure. The use of [32P]Pi allowed detection of these compounds. In the presence of HA, incorporation of [32P]Pi into phosphatidylinositol, phosphatidylinositol monophosphate, and phosphatidylinositol bisphosphate was increased. In addition, cultures exposed to [32P]Pi during stimulation with HA had an increased content of [32P]inositol monophosphate, bisphosphate, and trisphosphate.

Incidence of ras oncogene activation in lung carcinomas in Hong Kong

BACKGROUND

In Hong Kong, lung carcinomas contribute to the majority of cancer deaths among Chinese. Point mutational activation of ras oncogenes has been observed in several populations. The incidence of these mutations in Hong Kong lung carcinomas was investigated.

METHODS

Lung resections obtained from 52 Chinese patients whose conditions were newly diagnosed as non-small cell lung cancer, paraffin sections from 29 Chinese patients with previously diagnosed adenocarcinoma of the lung, and paraffin sections from 49 squamous cell carcinomas were examined for the presence of point mutations in Ki-ras codon 12, N-ras codon 61, and Ha-ras codon 12 oncogenes by allele-specific hybridization after specific amplification of appropriate regions of the DNA using the polymerase chain reaction.

RESULTS

Among the 130 lung carcinomas investigated, Ki-ras point mutations were detected in seven cases, of which six were adenocarcinomas and one a squamous cell carcinoma. No mutations were detected in the N-ras and Ha-ras codons.

CONCLUSIONS

The incidence of Ki-ras codon 12 point mutational activation in Chinese patients with adenocarcinomas was 6 of 63 (9.5%). The incidence of Ki-ras 12 point mutational activation among men with lung adenocarcinomas in Hong Kong (6 of 32 patients, 18.8%) is significantly different from that in women in Hong Kong (0 of 31 patients, 0%). Although ras oncogenes are implicated as having a role in the development of lung adenocarcinomas, especially among smokers, it is clear from these data that they are not associated with the unusually high incidence of lung adenocarcinomas among women in Hong Kong.

Recall and articulation of English and Chinese words by Chinese-English bilinguals

Three groups of subjects were tested to investigate the effect of language on the relationship between recall span and articulation rate. Native English-speaking monolinguals and native Chinese-speaking monolinguals recalled only English or Chinese words, respectively. Chinese-English bilinguals recalled both English and Chinese words. Articulation rates for English and Chinese monolinguals and Chinese-English bilinguals in each language were also obtained. When recall span was regressed on articulation rate, the slopes for Chinese and English words were significantly different for the Chinese-English bilinguals. This difference was not due to language proficiency but to phonological differences between English and Chinese.

Imaging of alveolar soft part sarcoma

The imaging investigations in six patients with alveolar soft part sarcoma (ASPS) are reviewed. Five patients presented with a pelvic or lower limb mass and one with haemoptysis from pulmonary metastases. Magnetic resonance imaging (MRI), CT, Doppler US and angiography studies demonstrated the highly vascular nature of this rare tumour and the frequent occurrence of pulmonary and intracranial metastases. Previously unreported Doppler US and MR evidence of multiple enlarged vessels and high blood flow within primary and secondary ASPS tumours is emphasized. Imaging is of considerable importance both for pre-operative localization and long term surveillance of this slow growing but invariably disseminating tumour.

Lexical and conceptual processing in Chinese-English bilinguals: further evidence for asymmetry

According to the asymmetry model of bilingual representation (Kroll & Stewart, 1994), the first language (L1) lexicon is closely tied to an underlying conceptual memory, whereas second language (L2) items are mostly associated with their L1 equivalents. An outcome of this architecture is that L1-to-L2, or forward, translation must be mediated by the conceptual memory, whereas L2-to-L1 (backward) translation takes a direct lexical path. Some predictions derived from this hypothetical structure were tested in the present study, which took into account, through analysis of covariance, variations in response production time, concept retrieval time, and some other characteristics associated with the individual test items. Proficient Chinese-English bilinguals were tested on delayed production (Balota & Chumbley, 1985), picture naming, word translation, and category matching. The expected asymmetrical pattern of translation latencies (i.e., forward > backward) was demonstrated, although it could be statistically explained by the item characteristic of familiarity; matching an L1 item to a category name was faster than matching an L2 item, suggesting relatively strong L1 conceptual links. The present results are best accommodated by a form of asymmetry that allows for nondominant L2-concept linkage, the use of which is conditional upon the familiarity of the test item to the bilingual.

Comparative bioavailability of two flurbiprofen products: stereospecific versus conventional approach

In this randomized, crossover study comparing the bioavailability of a film-coated (Ansaid) with a sugar-coated (Froben) 100 mg tablets of racemic flurbiprofen in 23 healthy young men, no significant differences were found for Cmax, tmax or AUC, using a nonstereoisomeric assay for flurbiprofen. Minor differences in the appearance of flurbiprofen in serum during the first 30-min post-dosing period were noted, with Ansaid appearing earlier than Froben. These differences likely reflect dissolution rate dissimilarity between the two products. Stereospecific determinations demonstrate a small (7.8 per cent) but significant difference in AUC of the active S-configuration (Froben greater than Ansaid). No significant differences between Ansaid and Froben were found for tmax or Cmax for the S-flurbiprofen. In bioequivalency studies of chiral drugs, stereospecific approaches provide a more accurate assessment of products.

Improving phonological awareness and word reading in a later learned alphabetic script

This study examines the effects of phonological skill training on consonantal phoneme deletion and word reading performance in two groups of adolescent Chinese readers who were also literate in English. The research questions were: (1) whether training would promote segmentation skills over and above years of contact with the alphabetic (English) writing system, given an initial logographic (Chinese) reading background; (2) whether improvements in segmentation skills due to training would enhance word reading in the alphabetic script. The participants were trained on phoneme counting, phoneme blending and rime judgement with English materials over a period of two months. Resultant changes in consonantal phoneme deletion and English word reading performance were examined. Significant improvements in both activities due to training were observed for the younger (mean age 12.7 years) but not the older (mean age 15.8 years) participants. Follow-up analyses showed that language proficiency might be the factor underlying this age effect. Individual differences in phoneme deletion uniquely predicted word reading for both age groups, although the relationship tended to be stronger for the less proficient than the more proficient members. These findings suggest that beyond years of normal reading instruction in the alphabetic system, specialized segmentation training could still contribute to promoting consonantal phonemic analysis that is not supported by the logographic first-learned script. Moreover, improved phonological skills do lead to better word reading in the later-learned writing system. Implications of the present findings for second script reading instruction are considered.