Lamotrigine inhibits depolarization-evoked Ca++ influx in dissociated amygdala neurons

Spectrophotometry with the Ca(++)-sensitive dye fura-2 was used to study the effect of lamotrigine (LAG) on the depolarization-evoked Ca++ influx in the acutely isolated basolateral amygdala neurons. Depolarization of the neurons with high K+ resulted in the elevation of intracellular Ca++ concentration [Ca++]i in a concentration-dependent manner. The K(+)-induced Ca++ influx was completely blocked in the Ca(++)-free solution or by Cd++, indicating that depolarization-induced increases in [Ca++]i were triggered largely, if not at all, by Ca++ entry from extracellular space and Ca++ entry occurred through voltage-dependent Ca++ channels. Application of LAG reduced the depolarization-evoked Ca++ influx in a concentration-dependent manner. The effect of LAG was markedly reduced in the presence of N-type Ca++ channel blocker omega-conotoxin-GVIA (omega-CgTX). These results suggest that the action of LAG is mediated, at least in part, by the modulation of N-type Ca++ channels.

Influence of age and gender on quantitative sacroiliac joint scintigraphy

The value of quantitative sacroiliac joint scintigraphy for detecting sacroiliitis is controversial. Age and gender may contribute to this discordance. In previous reports, the number of control groups has been small and might not exactly reflect the change of sacroiliac/sacral (SI/S) ratios related to different age. In addition, the selection of control subjects was not strict. In most studies, care was not taken to ensure that control subjects did not have a history of back pain or any other relevant conditions. In addition, there was no requirement for a normal radiograph as a condition of inclusion. The aim of our study was to evaluate the consequent changes in SI/S ratios, according to age (in 10-yr intervals) and gender.

METHODS

Over a period of 5 yr, 413 control subjects without a history of back pain, scoliosis, kyphosis, joint pain, arthritis, lesions within the pelvis, chemotherapy or systemic disease such as diabetes or systemic lupus erythematosus were included in this study. A posterior planar film of the pelvis was obtained to calculate SI/S ratio 3 hr after injection of 740 MBq 99mTc-methylenediphosphonate. Our data showed that: (a) the change in SI/S ratios related to age was significant in both females and males; (b) the SI/S ratios were higher in males younger than 30 yr and higher in men in the 41-50-yr age group and in females in other groups; (c) the SI/S ratios declined steadily with increasing age in females, whereas there were two plateaus in men aged 21-40 yr and 41-70 yr; (d) there were significant differences of SI/S ratios between the genders in certain age groups; and (e) no differences were found between left SI/S ratios and right SI/S ratios.

CONCLUSION

The influence of age and gender on SI/S ratios are substantial, and it is essential for each department to establish its own values for SI/S ratios based on gender and age (in 10-yr intervals).

Idiopathic intracranial hypertension without papilledema: a case-control study in a headache center

OBJECTIVE

To compare the clinical features of patients with chronic daily headache (CDH) with idiopathic intracranial hypertension without papilledema (IIHWOP) to those with normal CSF pressure.

METHODS

A case-control study was conducted at a tertiary headache center. Cases consisted of 25 consecutive patients (24 women, 1 man, 38 +/- 6 years) with IIHWOP diagnosed between June 1989 and June 1996. IIHWOP was diagnosed if pressure was 200 mm CSF on two occasions and there was no papilledema. Control subjects consisted of patients with refractory CDH who had normal CSF pressure on lumbar puncture performed between June 1992 and June 1996 (n = 60, 50 women, 10 men, 36 +/- 11 years). A structured telephone follow-up was done from July 1996 to March 1997. Comparisons made between the two groups included demographics and headache profiles, both at the initial evaluation and at follow-up.

RESULTS

The initial headache characteristics did not differ between the two groups: most had transformed migraine with analgesic overuse. Significant predictors of IIHWOP included pulsatile tinnitus (odds ratio [OR] = 13.0) and obesity (OR = 4.4). Visual symptoms did not differ significantly. The prognosis of the two groups of patients was similar.

CONCLUSIONS

Pulsatile tinnitus and obesity suggest possible IIHWOP in patients with CDH. Treatment of patients with increased intracranial pressure was not satisfactory.

Serotonin depresses excitatory synaptic transmission and depolarization-evoked Ca2+ influx in rat basolateral amygdala via 5-HT1A receptors

The actions of serotonin on rat basolateral amygdala neurons were studied with conventional intracellular recording techniques and fura-2 fluorimetric recordings. Bath application of 5-hydroxytryptamine (5-HT or serotonin) reversibly suppressed the excitatory postsynaptic potential in a concentration-dependent manner without affecting the resting membrane potential and neuronal input resistance. Extracellular Ba2+ or pertussis toxin pretreatment did not affect the depressing effect of 5-HT suggesting that it is not mediated through activation of Gi/o protein-coupled K+ conductance. The sensitivity of postsynaptic neurons to glutamate receptor agonist was unaltered by the 5-HT pretreatment. In addition, the magnitude of paired-pulse facilitation was increased in the presence of 5-HT indicating a presynaptic mode of action. The effect of 5-HT was mimicked by the selective 5-HT1A agonist 8-hydroxy-dipropylaminotetralin (8-OH-DPAT) and was blocked by the selective 5-HT1A antagonist 1-(2-methoxyphenyl)-4[4-(2-phthalimido)butyl]piperazine oxadiazol-3-yl]methyl]phenyl]-methanesulphonamide. In contrast, the selective 5-HT2 receptor antagonist ketanserin failed to affect the action of 5-HT. The effects of 5-HT and 8-OH-DPAT on the high K+-induced increase in [Ca2+]i were studied in acutely dissociated basolateral amygdala neurons. High K+-induced increase in [Ca2+]i was blocked by Ca2+-free solution and Cd2+ suggesting that Ca2+ entry responsible for the depolarization-evoked increase in [Ca2+]i occurred through voltage-dependent Ca2+ channels. Application of 5-HT and 8-OH-DPAT reduced the K+-induced Ca2+ influx in a concentration-dependent manner. The effect of 5-HT was completely abolished in slices pretreated with Rp-cyclic adenosine 3',5'-monophosphothioate (Rp-cAMP), a regulatory site antagonist of protein kinase A, suggesting that 5-HT may act through a cAMP-dependent mechanism. Taken together, these results suggest that functional 5-HT1A receptors are present in the excitatory terminals and mediate the 5-HT inhibition of synaptic transmission in the amygdala.

The value of CYFRA 21-1, a new tumor marker, in nasopharyngeal carcinoma

CYFRA 21-1 (CYFRA) is a newly-developed tumor marker which is useful in evaluating non-small cell lung carcinoma, especially the squamous cell type. The purpose of this study was to assess the clinical value of CYFRA in patients with nasopharyngeal carcinoma (NPC). Serum levels of CYFRA (CIS bio-International, France) were measured in 80 patients with untreated NPC. The histologic diagnosis of all patients was confirmed by biopsy. Twenty two (27.5%) of the tumors were classified as undifferentiated carcinoma, and 58 (72.5%) as squamous cell carcinoma. All patients with malignancy were classified according to the International Union Against Cancer (UICC) TNM classification system. In addition, 77 patients without evidence of neoplasm were included as controls. The cut-off value of CYFRA, determined at the 95th percentile of the standard Gaussian variate of controls, was 2.48 ng/ml. The results show that (1) the mean values of serum CYFRA in patients with NPC were significantly higher than those in the control subjects, (2) the overall diagnostic sensitivity of CYFRA in patients with NPC is 58.75%, (3) there was no significant difference between the CYFRA concentrations in patients with squamous cell carcinoma and those in patients with undifferentiated carcinoma, and that (4) there was good correlation between CYFRA values and the tumor stage. There is a statistical difference between T1-T2 patients and T3-T4 patients, and between N0 to N1 patients and N2 to N3 patients. Our results suggest that the CYFRA test may have a potential clinical role as a valuable test in patients with NPC.

Rhenium-188 microspheres: a new radiation synovectomy agent

Radiation synovectomy is efficacious in controlling the symptoms of rheumatoid arthritis. However, the procedure is not widely used because of concerns about leakage of radiopharmaceuticals from the treated joints. Leakage can be minimized by selecting particles of an appropriate size. In this study, we labelled microspheres with 188Re and analysed its biodistribution after intra-articular injection in rabbits with antigen-induced arthritis. Gamma camera imaging was performed to quantify the mean retention of 188Re in the knees. The mean retention of 188Re was 98.7, 94.6 and 93.6% at 1, 24 and 48 h, respectively. The biodistribution data revealed very low radioactivity in all organs at different times, which suggests the leakage of radiotracer from the knee was negligible. Our preliminary results indicate that 188Re microspheres are a potentially effective radiopharmaceutical for radiation synovectomy.

Role of endothelium in the control of mouse yolk sac stem cell differentiation

Studies in our laboratory have shown that as early as day 8.5 of development, mouse yolk sac cells can generate T cells when placed in a thymic microenvironment. At this stage, yolk sac cells can also differentiate into myeloid cells in vitro. B cell differentiation in vitro was achieved with day 9 yolk sac by providing a bone marrow stromal feeder layer. We have now established endothelial cell lines and clones from yolk sacs of day 8-12 mouse embryos. These vary in their ability to support stem cell maintenance and differentiation. Our principal work has been carried out with day 12 cloned endothelial cell lines. One clone supported the > 100 fold expansion of yolk sac hematopoietic stem cells that subsequently could generate B cells, T cells and myeloid cells both in vitro and in vivo. Preliminary experiments with endothelial cells from younger embryos are also described.

Value of gallium-67 scintigraphy in monitoring the renal activity in lupus nephritis

In this study, we evaluated the relationship between the gallium uptake in the kidneys and the results of renal biopsy. The renal uptake of gallium in 32 patients with lupus nephritis were evaluated according to the classification of the World Health Organization, the activity index (AI), and the chronicity index (CI). AI was significantly higher in patients with a positive gallium scan when compared with patients with a negative gallium scan (p = 0.0007). However, change in gallium uptake was not related to the CI or WHO classification (p = 0.68 and p = 0.79 respectively). Of the 16 patients with AI > or = 9, 13 (81.25%) had a positive gallium scan, while only 3 (18.7%) of the patients with AI < 9 had a positive scan. In addition, all patients (100%) with AI > or = 11 showed a positive gallium scan. We conclude that renal imaging with gallium has a good correlation with AI, and may be a useful alternative to renal biopsy in patients with lupus nephritis.

Selective enhancement of P-type calcium currents by isoproterenol in the rat amygdala

We investigated activation of beta-adrenergic receptor-adenylyl cyclase-cAMP cascade on the whole-cell voltage-dependent Ca2+ currents (ICa) in acutely isolated rat basolateral amygdala neurons. Application of beta-receptor agonist isoproterenol (Iso) caused a long-term enhancement of ICa. The effect of Iso was blocked by concurrent application of beta-receptor antagonist propranolol. However, delayed application of propranolol after the ICa enhancement did not affect Iso-induced potentiation, suggesting that the sustained effect was not caused by a slow washout of Iso. Nimodipine and omega-conotoxin-GVIA reduced the ICa by approximately 35 and approximately 29%, respectively, without reducing enhancement of ICa by Iso significantly. The modulation appeared to involve P-type current, because the enhancement was abolished after pretreatment with omega-agatoxin-IVA. Forskolin, an adenylyl cyclase activator, mimicked the action of Iso in enhancing ICa, and this effect was blocked by an inhibitor of cAMP cascade, indicating a cAMP-dependent mechanism. Iso also induced a long-term potentiation (LTP) of synaptic transmission, which could be prevented by P-type Ca2+ channel blockers. These results suggest that P-type Ca2+ channels were selectively upregulated in the basolateral amygdala neurons, and enhancement of P-type currents could contribute to presynaptic form of LTP.

Proton magnetic resonance spectroscopy in deep cerebral venous thrombosis

A 63-year-old man developed a severe left frontal headache followed by an acute change of mentality 6 days later. Magnetic resonance imaging revealed bilateral thalamic ischemia. Angiography confirmed the occlusion of deep cerebral veins. Proton magnetic resonance spectroscopy (1H-MRS) of the thalami showed normal N-acetylaspartate (NAA) peak and the presence of lactate peak, indicating a relatively preserved neuronal viability. The patient improved during the follow-up period, and returned to work 45 days after the onset of the disease. With 1H-MRS, prognosis following venous infarctions may be feasible.

A study of a new tumour marker, CYFRA 21-1, in squamous cell carcinoma of the head and neck, and comparison with squamous cell carcinoma antigen

CYFRA 21-1 (CYFRA) is a newly developed tumour marker which is useful in evaluating large cell lung carcinoma, especially the squamous cell type. The purpose of this study was to assess the clinical value of CYFRA for squamous cell carcinoma of the head and neck and compare the results with squamous cell carcinoma antigen (SCCA). Serum levels of CYFRA were measured in 168 patients with a newly diagnosed head and neck squamous carcinoma. In addition, 77 patients without evidence of neoplasm were included as controls. At the same time, SCCA was also determined. The cut-off values of CYFRA and SCCA, determined at the 95th percentile of the standard Gaussian variate of controls, were 2.48 ng/ml and 1.49 ng/ml respectively. The diagnostic sensitivity of CYFRA was superior to that of SCCA, especially for nasopharyngeal carcinoma. The sensitivity of CYFRA for nasopharyngeal carcinoma was much higher (58.3%) than that of SCCA (15.5%). However, the sensitivity of CYFRA is not satisfactory in all types of squamous carcinoma. For oral cancer, the sensitivity is only 25.6%. CYFRA is a useful serum marker for patients with certain types of head and neck squamous carcinoma, such as nasopharyngeal carcinoma and hypopharyngeal carcinoma. In addition, CYFRA may be also useful in monitoring recurrence of certain types of SCCHN, which are sometimes difficult to detect.

Osteoid osteoma in the talar neck: a report of two cases

This article describes two cases of juxta-articular osteoid osteoma of talar neck. Both patients were initially treated as having ankle sprains or arthritis before diagnosis of osteoid osteoma. A high index of suspicion and appropriate imaging studies are important to make an early diagnosis of this disorder. Once diagnosis is confirmed, en bloc resection and autogenous bone graft can cure the disorder.

Lamotrigine inhibits tetraethylammonium-induced synaptic plasticity in the rat amygdala

Although long-term potentiation was generally initiated by a brief tetanus, in the hippocampus, it could also be evoked by application of the K+ channel blocker tetraethylammonium. The present study was aimed at investigating the effect of lamotrigine, a new anticonvulsant, on the tetraethylammonium-induced potentiation in brain slices of the rat amygdala using intracellular recording techniques. Bath application of tetraethylammonium (20 mM) for 10 min resulted in a long-lasting enhancement of the amplitude of excitatory postsynaptic potentials to 235 +/- 12% of control (n = 6, P < 0.001). Pretreatment of the slices with nifedipine (10 microM) abolished the potentiation, suggesting that tetraethylammonium long-term potentiation in the amygdala is due to Ca2+ influx through voltage-dependent Ca2+ channels. By contrast, N-methyl-D-aspartate receptor activation was not required because D-2-amino-5-phosphonovalerate (50 microM) did not prevent the tetraehylammonium long-term potentiation. Superfusion of lamotrigine (50 microM) depressed the excitatory postsynaptic potential to 53.8 +/- 3.9% of control. Tetraethylammonium was subsequently added in the presence of lamotrigine but failed to enhance the excitatory postsynaptic potential. Bursts of Ca2+ spikes evoked by a depolarizing pulse or by synaptic stimulation under tetraethylammonium were depressed by lamotrigine. It is concluded that lamotrigine is capable of inhibiting tetraethylammonium-induced synaptic plasticity. The underlying mechanism is likely due to lamotrigine's inhibition of postsynaptic voltage-dependent Ca2+ channels. Considering that tetraethylammonium is a convulsant agent and brief seizure episodes induced long-term potentiation, fibre sprouting and the development of aberrant synaptic contacts, lamotrigine could be a potential neuroprotective agent, especially in pathological situations where excessive glutamate release occurs.

Risk factors for Alzheimer's disease: a case-control study

The extent of current knowledge of risk factors for Alzheimer's disease (AD) is still limited. We conducted a case-control study of 98 AD patients and 98 age- and sex-matched controls. Light smoking had a decreased risk for AD (AD: 2.0%, controls: 21.4%, odds ratio = 0.10, p = 0.003), whereas daily smoking showed a trend to increase the risk for AD (AD: 45.9%, controls: 26.5%, odds ratio = 1.73, p = 0.08). After multivariable analyses factors associated with AD included the presence of apolipoprotein epsilon4 allele, and the duration of well water consumption.

Effects of phenytoin on the amygdala neurons in vitro

The present study was aimed at elucidating the possible mechanisms underlying the anticonvulsant efficacy of phenytoin using intracellular recording techniques in the in vitro amygdalar slice preparation. Synaptic response mediated by the N-methyl-D-aspartate (NMDA) receptor (EPSPNMDA) was isolated pharmacologically by application of a solution containing non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (10 mumol/l) and gamma-aminobutyric acidA receptor antagonist bicuculline (20 mumol/l). Phenytoin inhibits the amplitude of EPSPNMDA without affecting the postsynaptic depolarization induced by exogenous application of NMDA. In addition, phenytoin increases the magnitude of paired-pulse facilitation which is consistent with a presynaptic mode of action. These results suggest that inhibition of transmitter release due to presynaptic blockade of Na+ and/or Ca2+ channels may account largely for the anticonvulsant efficacy of phenytoin.

Use of two-stage test statistic in the two-period crossover trials

For two-period crossover trials where the residual carryover can only exist in the presence of treatment effect, Willan (1988, Biometrics 44, 211-218) recommended use of the maximum test statistic that chooses the analysis with the larger test statistic corresponding to the parallel analysis and the crossover analysis. We construct two alternative two-stage test procedures, based on Grizzle's approach, that maintain the actual type I error rate at the desirable level. The power, accuracy, and precision of the analysis based on the modified two-stage procedures are compared to those based on the parallel analysis, crossover analysis, and the maximum test statistic.

Unilateral pulmonary edema during general anesthesia--report of two cases

Unilateral presentation of pulmonary edema, though well known to occur, is an uncommon entity. Previous reviews of this subject have discussed the different etiologies, which include rapid reexpansion of collapsed lung, down lung syndrome (gravitational edema), systemic-to-pulmonary arterial shunts, heart failure, compression or occlusion of pulmonary vasculatures, obstruction of a bronchus and an acute manifestation of neuropulmonary reaction (neurogenic pulmonary edema). Occurrence of this complication during surgery, however, is even rarer. We report 2 cases of unilateral pulmonary edema occurring during general anesthesia for elective surgery.

Comprehensive gastric emptying study for type-II diabetes mellitus dyspeptic patients

BACKGROUND

Gastrointestinal symptoms without demonstrable lesions in the upper gastrointestinal tract are common in diabetic patients. Scintigraphic liquid- and solid-phase gastric emptying studies and gastric emptying of indigestible particles were performed to determine the gastric emptying function in type-II diabetes mellitus patients with dyspepsia.

METHODS

Twenty type-II diabetic patients with symptoms suggestive of delayed gastric emptying were included. A gelatin capsule containing 10 rod-shaped radiopaque markers was ingested, along with the solid-phase test meal, to assess the emptying of indigestible particles. Scintigraphic liquid-phase gastric emptying studies were performed on a separate day.

RESULTS

There were 7 patients (35%) with delayed liquid-phase gastric emptying, 14 patients (70%) with delayed solid-phase gastric emptying, and 14 patients (70%) with abnormal gastric emptying of indigestible particles. There were only three patients (15%) with normal gastric emptying of both the liquid and solid phase. Furthermore, only one patient showed normal result in all three gastric emptying studies.

CONCLUSIONS

For determining abnormalities in gastric emptying function for type-II diabetic dyspepsia patients, comprehensive gastric emptying studies, including scintigraphic liquid- and solid-phase gastric emptying studies and gastric emptying of indigestible particles, are most helpful.

Family history: a comprehensive genetic risk assessment method for the chronic conditions of adulthood

Targeting individuals with increased risk for common, chronic disease can improve the efficiency and efficacy of preventive efforts by improving the predictability of screening tests and participant compliance. Individuals with the greatest risk for these disorders are those with a genetic susceptibility. The purpose of this study was to determine the feasibility of using a single, comprehensive family history as a method for stratifying risk for many preventable, common genetic disorders. Family histories obtained in a prenatal diagnostic clinic were reviewed regarding cardiovascular diseases, diabetes and several cancers; 42.5% of individuals reported a family history for at least one of the disorders under study. Familial coronary artery disease was most commonly reported (29% of participants), followed by noninsulin-dependent diabetes (14%). Qualitative characterization of disease susceptibility was also accomplished using family history data. For example, occurrence of different cancers within pedigrees was suggestive of familial cancer syndromes, and clustering of noninsulin-dependent diabetes and cardiovascular disease suggested an insulin resistance syndrome. Depending on the specific disease, 5 to 15% of at-risk individuals had a moderately increased risk (2 to 5 times the population risk), and approximately 1 to 10% had a high risk (absolute risks approaching 50%). Family history reports of common, chronic disease are prevalent among the population at large, and collection and interpretation of comprehensive family history data is a feasible, initial method for risk stratification for many preventable, chronic conditions. These findings may have important implications for disease prevention and management.

Normal data for lumbar spine bone mineral content in healthy Chinese men

The aim of this study was to evaluate the influence of age on bone mineral density (BMD) of teh lumbar spine for health Chinese men. In 430 healthy Chinese men (ages 20-92 years) living on Taiwan, BMD at the level of the 2nd to 4th lumbar vertebraes (L2-L4) was determined with a commercial dual-energy X-ray absorptiometer (DXA). Our study found that the peak BMD value of lumbar spines of healthy Chinese men was 1.056 +/- 0.127 g/cm2 which occurs from age 20 to 29. The results show that a linear correlation between the age and BMD of lumbar vertebraes for healthy Chinese is notable. Only slight decreases of BMD values in the different age groups are found. In comparison with the normal data of white men and Asian men from Japan and Korea, the mean BMD values of lumbar spines of Chinese men seem to be lower than those of the white, Japanese, and Korean men of the same ages. Our findings indicate that the influence of age and ethnicity may exist in the BMD values for healthy Chinese males.