Modification of sample size in group sequential clinical trials

In group sequential clinical trials, sample size reestimation can be a complicated issue when it allows for change of sample size to be influenced by an observed sample path. Our simulation studies show that increasing sample size based on an interim estimate of the treatment difference can substantially inflate the probability of type I error in most practical situations. A new group sequential test procedure is developed by modifying the weights used in the traditional repeated significance two-sample mean test. The new test has the type I error probability preserved at the target level and can provide a substantial gain in power with the increase of sample size. Generalization of the new procedure is discussed.

Exposure to low-intensity ultrasound increases aggrecan gene expression in a rat femur fracture model

The effects of ultrasound stimulation on various parameters of bone repair after diaphyseal injury were assessed in a standard rat femur fracture model. Bilateral closed femoral fractures were made in 79 skeletally mature male Long-Evans rats. An ultrasound signal consisting of a 200 microsecond burst sine wave of 0.5 MHz repeating at 1 kHz, with an intensity of 50 or 100 mW/cm2 spatial and temporal average, was applied to one fracture in each animal. The contralateral fracture was not exposed to ultrasound and served as a control. Mechanical testing of the healing fracture was performed 3 weeks after injury. In fractures treated with a 50 mW/cm2 ultrasound signal, the average maximum torque (223.5 +/- 50.5 Nmm compared with 172.6 +/- 54.9 Nmm, p = 0.022, paired t test) and average torsional stiffness (13.0 +/- 3.4 Nmm/degree compared with 9.5 +/- 2.9 Nmm/degree, p = 0.017) were significantly greater in treated than in control fractures. In animals treated with a 100 mW/cm2 ultrasound signal, the average maximum torque and torsional stiffness were greater in treated than in control fractures, but this trend did not reach statistical significance. Biochemical analysis of callus in ultrasound-treated and control fractures failed to demonstrate significant differences in cell number, collagen content, or calcium content. Evaluation of gene expression in fractures treated with 50 mW/cm2 ultrasound demonstrated a shift in the expression of genes associated with cartilage formation; aggrecan gene expression was significantly higher on day 7 after fracture and significantly lower on day 21 (p = 0.033 and 0.035, respectively). alpha 1(II) procollagen gene expression was similarly modified, but this trend did not reach statistical significance. Expression of genes coding for bone-related proteins, including alpha 1(I) procollagen, bone gamma-carboxyglutamic acid protein, alkaline phosphatase, and transforming growth factor-beta 1, did not differ between ultrasound-treated and control fractures. These data suggest that ultrasound stimulation increased the mechanical properties of the healing fracture callus by stimulating earlier synthesis of extracellular matrix proteins in cartilage, possibly altering chondrocyte maturation and endochondral bone formation.

Guidelines for Controlled Trials of Prophylactic Treatment of Chronic Migraine in Adults

In 1991 the Clinical Trials Subcommittee of the International Headache Society (IHS) developed and published its first edition of the Guidelines on controlled trials of drugs in episodic migraine because only quality trials can form the basis for international collaboration on drug therapy, and these Guidelines would ‘improve the quality of controlled clinical trials in migraine’. With the current trend for large multinational trials, there is a need for increased awareness of methodological issues in clinical trials of drugs and other treatments for chronic migraine. These Guidelines are intended to assist in the design of well-controlled clinical trials of chronic migraine in adults, and do not apply to studies in children or adolescents.

Chronic daily headache in Chinese elderly: prevalence, risk factors, and biannual follow-up

OBJECTIVE

To investigate the prevalence, risk factors, and prognosis of chronic daily headache (CDH) in a population of elderly Chinese subjects.

METHODS

A community-based survey of registered residents > or =65 years old (n = 2,003) in two townships of Kinmen Island in 1993. A neurologist used a structured questionnaire and clinical interview to make the diagnosis of headache. Subjects who had headaches > or =15 days/month for > or =6 months in the previous year were considered to have CDH. CDH was further classified into chronic tension-type headache (CTTH), CDH with migrainous features (CDH/MF), and other CDH. Person-to-person biannual follow-up of the subjects with CDH was done in June 1995 and August 1997.

RESULTS

A total of 1,533 people (77%) participated in our prevalence study. Sixty subjects (3.9%) fulfilled the criteria for CDH, with a higher prevalence in women (F/M: 5.6%/1.8%, p < 0.001). Of these subjects, 42 (70%) had CTTH, 15 (25%) had CDH/MF, and 3 (5%) had other CDH. Only 23% of those with CDH had consulted physicians for their headaches in the previous year. Multivariate logistic regression revealed the significant risk factors for CDH to be analgesic overuse (OR = 79), a history of migraine (OR = 6.6), and a Geriatric Depression Scale-Short Form score of > or =8 (OR = 2.6). The follow-up results in 1995 and 1997 showed that about two-thirds of the subjects still had CDH. Analgesic overuse (relative risk = 1.6) in 1993 was a significant predictor of persistent CDH at follow-up.

CONCLUSIONS

A total of 3.9% of this elderly population had CDH, with CTTH being the most common subtype. Almost two-thirds of those with CDH had persistent frequent headaches at follow-up. Analgesic overuse was a significant predictor of a poor outcome.

Effects of estrogen on cognition, mood, and cerebral blood flow in AD: a controlled study

OBJECTIVE

To examine the effects of estrogen therapy on cognition, mood, and cerebral blood flow in patients with AD.

BACKGROUND

Some studies have suggested estrogen may be effective in the treatment of AD. However, most of these studies were not controlled adequately.

METHODS

Fifty female AD patients were recruited in a randomized, double-blind, placebo-controlled 12-week trial. Each member of the estrogen-treated group received conjugated estrogen (Premarin) 1.25 mg/day. The primary outcome measures were the Cognitive Ability Screening Instrument (CASI), Clinical Dementia Rating (CDR), and Clinician Interview-Based Impression of Change (CIBIC-plus). The secondary outcome measures were Behavioral Pathology in Alzheimer's Disease (BEHAVE-AD), Hamilton Anxiety Rating Scale (HARS), Hamilton Depression Rating Scale (HDRS), and 99mTc hexamethylpropylene amine oxime SPECT of the brain.

RESULTS

No meaningful differences were found between the outcome measures (CASI, CDR, CIBIC-plus, BEHAVE-AD, HARS, HDRS, and cerebral blood flow) taken from the estrogen-treated group and those from the control group.

CONCLUSION

A 1.25-mg/day dose of Premarin administered for 12 consecutive weeks does not produce a meaningful effect on cognitive performance, dementia severity, behavior, mood, and cerebral perfusion in female AD patients. Because estrogen therapy has been suspected of yielding adverse effects, and its therapeutic effectiveness is in doubt, additional evaluation of its role in AD treatment ought to be conducted.

Low intensity ultrasound treatment increases strength in a rat femoral fracture model

Bilateral closed femoral shaft fractures were made in 22 male Long-Evans rats. In 16 animals, ultrasound was applied to one limb for 15 minutes daily 10 times within the first 14 postoperative days. The treated limbs received a 200 microseconds burst of 1.5 or 0.5 MHz sine waves repeated at 1.0 kHz at a spatial average and temporal average intensity of 30 mW/cm2. The contralateral limb of each animal served as a nontreated control. Six remaining animals with fractures and six additional animals without fractures received sham ultrasound treatment to control for the effects of anesthesia and handling. Fracture repair was evaluated on postoperative day 21 by radiography, mechanical testing in torsion, and histology. Five of 16 ultrasound-treated fractures showed obliteration of the fracture gap on radiographs, whereas none of the 28 controls did. The average maximum torque of fractures treated with either signal was 22% greater than that of the contralateral controls (p < 0.05). The stiffness of treated fractures was greater than that of control fractures, but the difference was significant only in animals treated with the 1.5 MHz signal (p < 0.02). Sham treatment did not affect repair in the control group. These results indicate that low-intensity pulsed ultrasound at either 0.5 or 1.5 MHz can accelerate fracture repair at 21 days in this highly controlled model.

Chronic daily headache in Taipei, Taiwan: prevalence, follow-up and outcome predictors

We conducted a two-stage population-based headache survey among subjects aged > or = 15 in Taipei, Taiwan. Subjects with chronic daily headache (CDH) in the past year were identified, interviewed and followed-up. CDH was defined as a headache frequency > 15 days/month, with a duration > 4 h/day. Of the 3377 participants, 108 (3.2%) fulfilled the criteria for CDH, with a higher prevalence in women (4.3%) than men (1.9%). TM was the most common subtype (55%), followed by CTTH (44%). Thirty-four per cent of the CDH subjects overused analgesics. At the 2-year follow-up, 35% of the CDH subjects still had CDH. The significant predictors for persistent CDH at follow-up included: older age ( > or = 40 years) (RR = 2.4), CDH onset after 32 years (RR = 1.8), CDH duration > or = 6 years (RR = 2.0), medication overuse (RR = 1.8), and "daily" headache (RR = 2.1). We found that CDH is not uncommon in the community and its prevalence is similar among different populations. Older subjects and those with medication overuse may have a more protracted course of illness.

Comorbidity of depressive and anxiety disorders in chronic daily headache and its subtypes

OBJECTIVE

To investigate the frequency of depressive and anxiety disorders in patients with chronic daily headache.

BACKGROUND

There is a lack of data in the literature on the extent of psychiatric comorbidity in patients with different subtypes of chronic daily headache.

METHODS

We recruited consecutive patients with chronic daily headache seen in a headache clinic from November 1998 to December 1999. The subtypes of chronic daily headache were classified according to the criteria proposed by Silberstein et al. A psychiatrist evaluated the patients according to the structured Mini-International Neuropsychiatric Interview to assess the comorbidity of depressive and anxiety disorders.

RESULTS

Two hundred sixty-one patients with chronic daily headache were recruited. The mean age was 46 years, and 80% were women. Transformed migraine was diagnosed in 152 patients (58%) and chronic tension-type headache in 92 patients (35%). Seventy-eight percent of patients with transformed migraine had psychiatric comorbidity, including major depression (57%), dysthymia (11%), panic disorder (30%), and generalized anxiety disorder (8%). Sixty-four percent of patients with chronic tension-type headache had psychiatric diagnoses, including major depression (51%), dysthymia (8%), panic disorder (22%), and generalized anxiety disorder (1%). The frequency of anxiety disorders was significantly higher in patients with transformed migraine after controlling for age and sex (P =.02). Both depressive and anxiety disorders were significantly more frequent in women.

CONCLUSION

Psychiatric comorbidity, especially major depression and panic disorders, was highly prevalent in patients with chronic daily headache seen in a headache clinic. These results demonstrate that women and patients with transformed migraine are at higher risk of psychiatric comorbidity.

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.

Distinct associations of HLA class II genes with inflammatory bowel disease

BACKGROUND

There are relatively few studies of HLA class II association either with Crohn's disease (CD) or ulcerative colitis (UC). The few available association studies have been carried out by serological techniques, and the results from these studies are inconclusive.

METHODS

The association between HLA class II genes was studied using molecular genotyping in combination with allele-specific oligonucleotide hybridization by polymerase chain reactions.

RESULTS

In UC (n = 74), we observed a positive association with the HLA DR2 allele (P = 0.008) and negative associations with the DR4 (P = 0.018) and DRw6 (P = 0.028) when compared with ethnically matched controls (n = 77). No associations were observed with any DQ alleles. In contrast, in CD (n = 95) we observed a positive association with the combination of DR1 and DQw5 alleles (P = 0.021). Furthermore, stratifying DR1 and DQw5 alleles indicated that neither allele was independently associated with CD, suggesting that the association was with the haplotype rather than either of the alleles individually. A suballele of DQw5, DQB1*0501, contributed this haplotypic association (P = 0.012).

CONCLUSIONS

DR and DQ molecules firmly separate UC and CD on genetic grounds, suggesting that the contribution of the HLA class II genes to the disease susceptibility is quite different for the two disorders.

Quality of life differs among headache diagnoses: analysis of SF-36 survey in 901 headache patients

This paper presents the results of health-related quality of life (HRQoL) in 901 patients consecutively visiting a headache clinic of a national medical center in Taipei, Taiwan. HRQoL was evaluated with the Medical Outcome Study-Short Form (SF-36) and the Hospital Anxiety and Depression Scale (HADS). According to the classification criteria for chronic daily headache (CDH) proposed by Silberstein et al. (Neurology 47 (1996) 871) five hundred and ninety-three (66%) patients had CDH, of whom transformed migraine (TM) was diagnosed in 310, and chronic tension-type headache (CTTH) in 231. One hundred and ninety-three patients had episodic migraine. All SF-36 scale scores significantly correlated with the HADS scores and the intensity and frequency of pain. Compared with the normative data, a pervasive multi-dimensional decline of the SF-36 scores was noted among the headache patients except for the physical functioning scale. The decline was most remarkable in the role limitations of physical and emotional dimensions and in the bodily pain. An increasing impairment of the SF-36 scores was noted from migraine to CTTH to TM. After controlling for the HADS, age, gender, education, and chronic illness by multiple linear regression analyses, the patients with TM had the worst SF-36 profile; whereas, the patients with CTTH and migraine had compatible results. This study is the first to demonstrate that the SF-36 scores differ among headache diagnoses. Psychological distress, as well as the percentages of the types of patients, greatly influenced the SF-36 scores in hospital-based headache samples. Our findings also suggest that improvement in the pain profile as well as psychological well-being can predict a generalized improvement in the SF-36 scales in headache patients.

Prevalence and subtypes of dementia in Taiwan: a community survey of 5297 individuals

OBJECTIVE

To study the prevalence rate of dementia in Taiwan, the relative frequencies of its subtypes, and its associations with age, education, gender, and residence location.

PARTICIPANTS

A total of 2753 men and 2544 women from four urban and four rural communities participated. Their age ranged from 41 to 88 years; 28% of them were at least 65 years old. Their education ranged from 0 to 20 years; 27% of them had less than 1 year of formal schooling.

DESIGN

Phase I was a screening survey by trained nurses who administered a Chinese version of the Mini-Mental State Examination, the MMSE-T1, to all participants. Phase II involved the assessment for dementia by neurologists on the 1521 individuals who had scored less than 24 on the 30-point MMSE-T1.

MAIN RESULTS

Thirty-one cases of dementia were identified by the DSM-III-R criteria, including 18 cases of Alzheimer's disease, 10 cases of vascular dementia, and three cases of other dementias. The prevalence rate in individuals aged 65 and over was 2.0%. Aging and illiteracy were associated with higher rates of dementia; gender and residence location made no difference.

CONCLUSIONS

The prevalence rate of dementia was low in this Chinese population. Consistent with common findings from other parts of the world, a high rate of dementia was associated with older age and illiteracy, and Alzheimer's disease was the most frequent cause.

Psychometric evaluation of a Chinese (Taiwanese) version of the SF-36 health survey amongst middle-aged women from a rural community

To test the psychometric properties of the Chinese (Taiwanese) version of the short form 36 health survey (SF-36), 1,439 women, aged 40-54 years and living in Kinmen (a Taiwanese island reflecting a predominantly rural community) were recruited to participate in this survey. The rate of unavailable data points for the 36 tested items remained consistently low, and item-discriminate validity was high (95%) for all subscales. Cronbach's alpha coefficient remained above the 0.70 threshold criterion for all scales except for social functioning and bodily pain. Principal components analysis supported the two major dimensions of health, physical and mental, in the internal structure of the SF-36 scales, although the dimensions did not match the hypothesized association very well. Poorer health profiles were associated with physical and mental conditions. The mental health subscores in the SF-36 test correlated highly with the associated hospital anxiety and depression score (Spearman rank correlation coefficient = -0.62). In conclusion, the reliability and validity tests performed on the data collected support the cross-cultural application of the Chinese (Taiwanese) version of the SF-36 test.

The basic helix-loop-helix transcription factor HESR1 regulates endothelial cell tube formation

Human endothelial cells can be induced to form capillary-like tubular networks in collagen gels. We have used this in vitro model and representational difference analysis to identify genes involved in the formation of new blood vessels. HESR1 (HEY-1/HRT-1/CHF-2/gridlock), a basic helix-loop-helix protein related to the hairy/enhancer of split/HES family, is absent in migrating and proliferating cultures of endothelial cells but is rapidly induced during capillary-like network formation. HESR1 is detectable in all adult tissues and at high levels in well vascularized organs such as heart and brain. Its expression is also enriched in aorta and purified capillaries. Overexpression of HESR1 in endothelial cells down-regulates vascular endothelial cell growth factor receptor-2 (VEGFR2) mRNA levels and blocks proliferation, migration, and network formation. Interestingly, reduction of expression of HESR1 by antisense oligonucleotides also blocks endothelial cell network formation in vitro. Finally, HESR1 expression is altered in several breast, lung, and kidney tumors. These data are consistent with a temporal model for HESR1 action where down-regulation at the initiation of new vessel budding is required to allow VEGFR2-mediated migration and proliferation, but re-expression of HESR1 is necessary for induction of tubular network formation and continued maintenance of the mature, quiescent vessel.

Prevalence of migraine in Taipei, Taiwan: a population-based survey

We conducted the first population-based migraine survey in Taipei, Taiwan, using a validated questionnaire administered by interviewers during the period from August 1997 to June 1998. Our target population comprised all individuals (age > or = 15 years) in 1400 randomly selected households. Migraine diagnoses were made according to the classification criteria of migraine without aura proposed by the International Headache Society, 1988, except that attacks with a duration of between 2 h and 4 h were also included. Of the 4434 eligible subjects in the 1211 respondent households, 3377 (76%) completed the questionnaire. After adjustment for age and sex distribution according to the population structure, the prevalence of migraine was 9.1% (F/M 14.4%/4.5%). Fifty-four percent of the subjects with migraine had consulted a physician about their headaches in the past year. However, only 18% of them reported that their migraine had been diagnosed by physicians. This study found that Taipei residents have the highest migraine prevalence of all Chinese populations studied, although it is still in the low range of prevalence compared with the results from Western countries.

Human very-long-chain acyl-CoA synthetase: cloning, topography, and relevance to branched-chain fatty acid metabolism

Very-long-chain acyl-CoA synthetases (VLCS) activate very-long-chain fatty acids (VLCFA) containing 22 or more carbons to their CoA derivatives. We cloned the human ortholog (hVLCS) of the gene encoding the rat liver enzyme (rVLCS). Both hVLCS and rVLCS contain 620 amino acids, are expressed primarily in liver and kidney, and have a potential peroxisome targeting signal 1 (-LKL) at their carboxy termini. When expressed in COS-1 cells, hVLCS activated the VLCFA lignoceric acid (C24:0), a long-chain fatty acid (C16:0), and two branched-chain fatty acids, phytanic acid and pristanic acid. Immunofluorescence and immunoblot studies localized hVLCS to both peroxisomes and endoplasmic reticulum. In peroxisomes of HepG2 cells, hVLCS was topographically oriented facing the matrix and not the cytoplasm. This orientation, coupled with the observation that hVLCS activates branched-chain fatty acids, suggests that hVLCS could play a role in the intraperoxisomal reactivation of pristanic acid produced via alpha-oxidation of phytanic acid.

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.

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) as a screening tool for dementia for a predominantly illiterate Chinese population

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) provides ratings of an individual's changes in everyday cognitive functions during the previous 10 years. Original studies conducted in Australia showed that its score was not influenced by the subjects' educational backgrounds and that it performed at least as well as the Mini-Mental State Examination (MMSE) as a screening instrument for dementia. The subjects of the present study were Chinese and included 399 community residents and 61 dementia patients. Their ages ranged from 50 to 92 years; their education levels ranged from 0 to 19 years, and 63% of them had never attended school. We administered the IQCODE to informants and the Cognitive Abilities Screening Instrument (CASI), from which a CASI-estimated score of the MMSE (MMSE-CE) can be obtained, to the subjects. The diagnosis of dementia was made independently by physicians according to the DSM-III-R criteria based on semistructured interview and testing, neurologic examination, and standardized assessments of cerebral vascular disease, Parkinson's disease, and depression. The Chinese IQCODE showed no association with the subjects' education level or gender, low association with their age, and moderately high association with their MMSE-CE score. The area under the receiver operating characteristic curve of the IQCODE was significantly larger than that of the MMSE-CE for the whole group and for the subgroup with 1 to 19 years of education but not for the subgroup with 0 years of education. Nine of the 26 items of the IQCODE could be deleted without appreciable reduction in sensitivity and specificity. The IQCODE (1) can be shortened to 17 items, (2) had good cross-cultural applicability, and (3) was better than the MMSE-CE as a screening tool for dementia in a population with large variation in educational backgrounds.

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.

Depressive disorders among older residents in a Chinese rural community

BACKGROUND

Two recent surveys of depression among Chinese elderly people sampled different populations, used different case ascertainment methods and resulted in a seven-fold difference in prevalence rates. The present study was conducted to compare prevalence rates obtained with two commonly used methods in the same population, and to examine the risk factors for depression.

METHODS

The target population included all residents aged 65 years and over in a rural Chinese community. Participants were interviewed for demographic and medical information, examined by a neurologist and administered Chinese versions of the Geriatric Depression Scale-Short Form (GDS-S), the Cognitive Abilities Screening Instrument (CASI) and an Activities of Daily Living (ADL) form. Individuals who screened positive on the GDS-S were also interviewed by a psychiatrist for diagnosis according to the DSM-III-R criteria.

RESULTS

Among the 1313 participants, 26% screened positive on the GDS-S and 13% were diagnosed as having a depressive disorder, including 6.1% with major depression. Individuals with depressive disorders were more likely to have poor ADL scores, lower CASI scores, and chronic physical illnesses. They were also more likely to be female, older, illiterate and without a spouse, but adding these variables did not increase the overall association with the GDS-S score.

CONCLUSIONS

Depression was quite common in this Chinese rural geriatric population. The prevalence rate was twice as high when judged by depression symptomatology rather than clinical diagnosis. The critical risk factors were functional impairments, poor cognitive abilities and the presence of chronic physical illnesses.

Surgical management of carotid body tumors

OBJECTIVE

The goal was to review our experience in the management of carotid body tumors at a tertiary referral center.

METHODS

A retrospective review was performed of patients at University of California-Los Angeles Medical Center in whom carotid body tumor was diagnosed between 1973 and 1998.

RESULTS

Twenty-nine patients with 36 carotid body tumors were identified. Thirty-five operations were performed. Seventeen patients underwent preoperative embolization. The blood loss for these patients was less than for those without embolization. Five patients had preoperative cranial nerve deficits. Neurologic deficits were noted in 41% of patients immediately after surgery. In 24% of patients, the deficits were permanent.

CONCLUSION

Surgical resection is the treatment of choice for carotid body tumors. Embolization immediately before surgery decreases blood loss and facilitates tumor removal. In our series, the risk of new postsurgical cranial nerve deficits was small. Observation of these tumors is not recommended because progressive growth is associated with increased risk of neurologic deficits.

Behavioral disorders and caregivers' reaction in Taiwanese patients with Alzheimer's disease

OBJECTIVES

To evaluate the applicability of the Chinese version of the Neuropsychiatric Inventory Scale (NPI), and to explore the neuropsychiatric manifestations of Taiwanese patients with Alzheimer's disease (AD) and caregiver distress.

METHOD

The Mini-Mental State Examination (MMSE) was administered to 95 patients with AD, and their caregivers were interviewed with the NPI. To assess the test-retest reliability of the Chinese version of the NPI, 86 caregivers underwent a second NPI 3 weeks later.

RESULTS

The Cronbach's alpha coefficient of the Chinese version of the NPI was .76. The test-retest reliabilities of frequency, severity, and caregiver burden scores were significantly correlated; overall correlations were .85 for frequency (p < .001), .82 for severity (p < .001), and .79 (p < .001) for distress. Factor analysis was carried out, and three groups, "mood and psychosis," "psychomotor regulation," and "social engagement," were found. Aberrant motor behavior was the most frequently recorded behavior; euphoria was the least. There was no significant correlation between the patient's MMSE and the caregiver distress score, except for aberrant motor activity (r = -.23, p = .03). The symptoms most frequently reported to be severely distressing to caregivers were aberrant motor activity, anxiety, agitation, and delusions.

CONCLUSIONS

These results indicate that the NPI is a reliable tool to assess behavioral disturbance and caregiver distress in Taiwanese AD patients. These findings also confirm the high prevalence of psychopathology among AD patients and the marked distress produced by many of these behaviors.

Inhibition of N-type calcium currents by lamotrigine in rat amygdalar neurones

Lamotrigine (LAG) is a new anticonvulsant drug for the treatment of partial and secondarily generalized seizures. The present study was aimed at elucidating the possible involvement of Ca2+ channels in the action of LAG using whole-cell patch clamp recordings in acutely dissociated amygdalar neurones. Whole-cell Ca2+ currents (ICa) were elicited by 200 ms step commands from -70 mV to -10 mV. Application of LAG reduced the ICa by an average of 40.3 +/- 3.2%. The inhibition of ICa by LAG was markedly reduced or eliminated in the presence of the N-type Ca2+ channel blocker omega-conotoxin-GVIA (1 microM). These results suggest that LAG may exert its anticonvulsant effect through inhibition of presynaptic N-type Ca2+ channels, thereby reducing glutamate release.

A simple Chinese risk score for undiagnosed diabetes

AIMS

A diabetes risk score for screening undiagnosed diabetes was constructed and validated in Chinese adults.

METHODS

Two consecutive population-based diabetes surveys among Chinese adults aged 20-74 years were conducted in 2002 (n = 1986) and 2006 (n = 4336). Demographic and anthropometric measures were collected following similar procedures. Standard 2-h 75-g oral glucose tolerance tests (OGTTs) were performed to diagnose diabetes in both surveys. Fasting capillary plasma glucose (FCG) and glycated haemoglobin (HbA(1c)) were also measured together with the OGTTs on the same day of the 2006 survey. Beta coefficients estimated using logistic regression analysis derived from data of the 2002 survey were used to develop the risk assessment algorithm. The performance of the algorithm was validated in the study population of the 2006 survey.

RESULTS

Of all the variables tested, waist circumference, age and family history of diabetes were significant predictors of diabetes and were used to construct the risk assessment score. The score, ranging from 3 to 32, performed well when applied to the study population of the 2006 survey. The area under the receiver operating characteristic curve was 67.3% (95% CI, 64.9-69.7%) for the score, while it was 76.3% (73.5-79.0%) for FCG alone and 67.8% (64.9-70.8%) for HbA(1c) alone. At a cut-off point of 14, the sensitivity and specificity of the risk score were 84.2% (81.0-87.5%) and 39.8% (38.2-41.3%).

CONCLUSIONS

The risk score based on age, waist circumference and family history of diabetes is efficient as a layperson-oriented diabetes screening tool for health promotion and for population-based screening programmes.

Assessing cognitive abilities and dementia in a predominantly illiterate population of older individuals in Kinmen

A community survey of dementia was conducted on a Chinese islet. A total of 221 men and 234 women in the age range of 50-92 were assessed. The Cognitive Abilities Screening Instrument (CASI), a 100-point cognitive test designed for cross-cultural studies and adapted in Chinese for individuals with little or no formal education, was administered twice by trained field workers with a retest interval of 3 to 4 weeks. In addition, all participants were assessed by physicians who did not know the CASI scores. The physicians' assessment included a complete neurological examination, plus semi-structured tests and interviews covering cognitive abilities, daily activities, depression, cerebrovascular disease, and Parkinson's disease. Dementia was diagnosed by consensus among the physicians according to the DSM-III-R criteria. Among the 455 participants, 16 cases of dementia were identified, including 13 with probable Alzheimer's disease and 1 each with vascular dementia, Parkinson's disease, and alcoholism. The rates of dementia were 0, 3.9 and 11.5% for the age groups of 50-69, 70-79 and 80-92; and 4.4, 2.0 and 0% for the education groups of 0-1, 2-6 and 7-15 years of schooling. No sex difference was found after controlling for education. The Chinese version of the CASI had an intraclass retest reliability of 0.90. Using a cut-off score of < or = 50 for dementia, the sensitivity was 0.88 and the specificity was 0.94. The preliminary study suggests that the CASI can be used in Chinese populations with generally low education levels and that Alzheimer's disease was the most common type of dementia in this population.