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Biomedical subjects

L M Li

Publications and source records attributed to L M Li.

At least 55 records · Page 3Linked to original sources
PubMed1998

Hypothalamic hamartomas and gelastic epilepsy: a spectroscopic study.

BACKGROUND: Patients with hypothalamic hamartomas present with epileptic attacks of laughter and later experience multiple seizure types and cognitive decline, suggestive of secondary generalized epilepsy. It has been suggested in the past that gelastic seizures originate in the temporal lobes rather than in the hamartoma, but temporal resections have been ineffective. Recent electrophysiologic evidence suggests that the epileptogenic discharges may originate in the hamartoma itself. METHODS: We used proton magnetic resonance spectroscopic imaging to quantify the amount of neuronal damage in the temporal lobes and hamartomas of patients with hypothalamic hamartomas and gelastic seizures. Five patients were studied and the relative intensity of N-acetylaspartate to creatine (NAA/Cr) was determined for both temporal lobes as well as for the hamartoma. These values were compared with signals from the temporal lobes and hypothalami of normal control subjects. RESULTS: NAA/Cr was not significantly different from normal control subjects for either temporal lobe, nor was there a significant asymmetry between the two temporal lobes for any of the patients. NAA resonance signals were present in the hamartomas, and the ratio of NAA to Cr was decreased in the hamartomas compared with the hypothalami of normal control subjects (t = 4.5, p = 0.005). CONCLUSIONS: We found no detectable neuronal damage in the temporal lobes of patients with hypothalamic hamartomas and gelastic epilepsy. This is further evidence that gelastic seizures do not originate in the temporal lobes of these patients.

Adolescent↗
PubMed1997

Periventricular nodular heterotopia and intractable temporal lobe epilepsy: poor outcome after temporal lobe resection.

We describe 5 women and 5 men with periventricular nodular heterotopia and electroclinical features suggestive of temporal lobe epilepsy, who were surgically treated for control of medically refractory seizures. Magnetic resonance imaging revealed bilateral periventricular nodular heterotopia in 7 of the 10 patients. Because of the lack of clear localization, 6 patients were studied with intracranial depth electrode recordings. Seizures were of hippocampal onset (3 patients), regional temporal lobe onset (2 patients), or occipital-temporal onset (1 patient). Anterior temporal lobectomy was performed in 6 patients; selective amygdalohippocampectomy, in 1; and anterior temporal lobectomy plus resection of the heterotopic tissue, in 3. None of the 9 patients followed for more than 12 months postoperatively were seizure free. Two patients were initially seizure free for approximately 18 months, but then seizures recurred. One patient had a major reduction in seizure frequency at a 39-month follow-up after most of the unilateral heterotopic tissue was included in the temporal resection. Temporal resection did not lead to a long-term favorable outcome in this group of patients with periventricular nodular heterotopia and epileptogenic discharges involving the temporal lobe. This suggests a more widespread disorder with epileptogenic activity possibly originating in or near the heterotopic tissue. The clinical and electrographic features of periventricular nodular heterotopia pointing to temporal lobe origin are misleading and temporal resection does not result in long-term cessation of seizures.

Adult↗
PubMed1997

Surgical treatment of patients with single and dual pathology: relevance of lesion and of hippocampal atrophy to seizure outcome.

Modern neuroimaging can disclose epileptogenic lesions in many patients with partial epilepsy and, at times, display the coexistence of hippocampal atrophy in addition to an extrahippocampal lesion (dual pathology). We studied the postoperative seizure outcome of 64 patients with lesional epilepsy (median follow-up, 30 months) and considered separately the surgical results in the 51 patients with a single lesion and in the 13 who had dual pathology. In patients with a single lesion, 85% were seizure free or significantly improved (Engel's class I-II) when the lesion was totally removed compared with only 40% when there was incomplete resection (p < 0.007). All three patients with dual pathology who had both the lesion and the atrophic hippocampus removed became seizure free. In contrast, only 2 of the 10 patients with dual pathology undergoing surgery aimed at the lesion or at the hippocampus alone became seizure free (p < 0.05), although 4 of them showed significant improvement (Engel's class II). We conclude that the outcome in patients with single epileptogenic lesions is usually dependent upon the completeness of lesion resection. In patients with dual pathology, surgery should, if possible, include resection of both the lesion and the atrophic hippocampus.

Adolescent↗
PubMed1997

[Inhibition of tumor invasion and metastasis by retinoid 4-APR].

The anti-invasive and anti-metastatic effects with new retinoid 4-acetamidophenyl retinoate (4-APR) were studied using in vitro and in vivo experiments. 4-APR, at the dose of 43.3 mg.kg-1.day-1 p.o., was shown to reduce the spontaneous lung metastatic foci of Lewis lung carcinoma. 4-APR was also found to inhibit the artificial lung metastasis of B16-F10 cells by 67.9% and 36.6% and suppress the reconstituted basement membrane invasion of B16-F10 cells by 54.2% and 41.9% at the concentrations of 10(-5) mol.L-1 and 10(-6) mol.L-1, respectively.

Animals↗
PubMed1997

[Study on the mortality of injury in elderly population in Hai Dian District, Beijing].

We have analyzed the report on data of all deaths among 60 year-olds and above in Hai Dian District from 1987 to 1994. The results showed that the mortality of injuries in aging group had a decreasing trend in the last 8 years. The main reasons of death of injuries in this area are fall, traffic accident, poisoning and suicide. Thus the prevention of injury in elderly population should be considered very important.

Accidents, Traffic↗
PubMed1996

Bilateral hippocampal volume loss in patients with a history of encephalitis or meningitis.

Volumetric analysis of high-quality magnetic resonance imaging (MRI) scans identifies asymmetric hippocampal atrophy in most patients with temporal lobe epilepsy. However, bilateral hippocampal atrophy can be missed by unnormalized volume measures. We considered two patient groups with temporal lobe epilepsy, one with a history of febrile convulsions (FC, n = 14) and one with a history of encephalitis or meningitis (E/M, N = 12), to compare the prevalence of bilateral volume loss between the groups. A volume normalization process defines a normal range of hippocampal volumes in control subjects (n = 32). Normalized volumes indicated that 11 of 14 subjects with a history of FC had unilateral hippocampal atrophy and 9 of 12 subjects with a history of E/M had bilateral hippocampal atrophy as compared with the controls. Visual assessments of unilateral hippocampal atrophy (n = 17) correlated well with measured unilateral volume loss (n = 14 ), but visual assessment of bilateral hippocampal atrophy (n = 3) correlated poorly with measured bilateral volume loss (n = 12). Mean age at seizure onset was lower in the FC group (7 years) than in the E/M group (13 years), but other clinical features were similar between the two groups. Hippocampal volume normalization is necessary to detect bilateral volume loss, which is common in patients with a history of encephalitis or meningitis.

Adolescent↗
PubMed1996

Felbamate as add-on therapy.

Felbamate is a novel anti-epileptic drug (AED) which has recently been associated with reports of aplastic anaemia and liver failure. We have conducted an open-label add-on assessment of the tolerability and efficacy of this compound in 111 adult patients with refractory epilepsy attending a tertiary referral centre. The mean follow-up period was 4 months (range 1-8 months). Sixty-three (57%) were ongoing, 38 (34%) had discontinued felbamate and a further 10 (9%) were withdrawing. Reasons for discontinuing felbamate were adverse events in 23 (21%), increase in seizures in 11 (10%) and lack of efficacy in 14 (12%). Behavioural disturbances occurred in 14 patients, being the most likely adverse event to result in discontinuation. No cases of aplastic anaemia or liver failure were observed in this group. Felbamate appears to be a broad-spectrum AED. Seven percent of the patients had more than 95% seizure reduction (2 patients were seizure free), whilst a further 13% had significant improvement ( > 50% reduction in seizure frequency). In conclusion, felbamate seems to be an effective AED. In view of its association with potentially life-threatening complications, its use should however be restricted to patients with medically refractory epilepsy.

Adult↗
PubMed1996

Allergic skin rash with lamotrigine and concomitant valproate therapy: evidence for an increased risk.

Cutaneous rash is one of the commonest adverse events associated with lamotrigine. We assessed whether the risk is increased in patients receiving concomitant valproate therapy in a population of 103 adult patients with intractable epilepsy, who had lamotrigine added to their treatment. Of the 33 patients taking valproate, 10 (30%) developed a rash, whilst of the 70 not taking valproate, only 6 (8%) developed a rash. This suggests a significantly higher risk of cutaneous rash when starting lamotrigine in patients already taking valproate (p < 0.02).

Adolescent↗
PubMed1996

[A five years surveillance on neural system birth defects in rural areas of China].

A total number of 167,274 births were observed on birth defects in rural areas 1968-1990 in China. The results showed that there were 361 cases of neural system defects, accounting for 31.45% in all birth defects. The incidence of neural system defects was 2.19% with hydrocephalus, anencephalus and spinal bifida 0.89%, 0.87%, 0.36% respectively. The distribution of neural system birth defects showed that incidence in northern part of the country was higher than that of in the south while in winter--spring was higher than in summer--autumn. Results of unconditional logistic regression analysis demonstrated that risk factors were related to neural system defects as maternal education level, parity, delivery mode and lower birth weight.

Anencephaly↗
PubMed1996

[Studies of antitumor and chemopreventive agents against neoplasm: synthesis of coumarin 3-glyoxal derivatives and relationship between structure and antimutagenic activity].

It has been shown that alpha-glyoxal and its derivatives possess antivirus and antitumor activities. Eighteen new coumarin 3-glyoxal derivatives were synthesized in our laboratory. The fragmentation pattern of MS and the characteristic signals of 1HNMR of these compounds have also been studied. In pharmacological test in vitro most of these analogues showed antimutagenic activities, among them, compound 9 exhibited very strong antimutagenic activity and eight compounds showed strong effects. The struture-activity relationship and the possible active substructure responsible for the activity of these compounds were discussed. As expected, coumarin 3-glyoxals showed higher antimutagenic activities than their 3-acetyl coumarin counterparts. We also found that alkylation or esterification of 7-hydroxy were favorable to their activities.

Antimutagenic Agents↗
PubMed1995

High resolution magnetic resonance imaging in adults with partial or secondary generalised epilepsy attending a tertiary referral unit.

In the past the underlying structural abnormalities leading to the development of chronic seizure disorders have usually only been disclosed by histological examination of surgical or postmortem material, due to their often subtle nature that was beyond the resolution of CT or early MRI. The MRI findings in 341 patients with chronic, refractory epilepsy attending The National Hospital for Neurology and Neurosurgery and Chalfont Centre for Epilepsy are reported. Studies were performed on a 1.5 Tesla scanner with a specific volumetric protocol, allowing the reconstruction of 1.5 mm contiguous slices throughout the whole brain. Direct visual inspection of the two dimensional images without the use of additional quantitative measures showed that 254/341 (74%) were abnormal. Twenty four (7%) patients had more than one lesion. The principal MRI diagnoses were hippocampal asymmetry (32%), cortical dysgenesis (12%), tumour (12%), and vascular malformation (8%). Pathological confirmation was available from surgical specimens in 70 patients and showed a very high degree of sensitivity and specificity for the different entities. The advent of more widely available high resolution MRI should make it possible to identify the underlying pathological substrate in most patients with chronic partial epilepsy. This will allow a fundamental reclassification of the epilepsies for both medical and surgical management, with increasing precision as new methods (both of acquisition and postprocessing) are added to the neuroimaging battery used in clinical practice.

Adolescent↗
PubMed1995

Ictal ECG changes in temporal lobe epilepsy.

Changes in cardiac rhythm may occur during epileptic seizures and this has been suggested as a possible mechanism for sudden unexpected death amongst patients with chronic epilepsy (SUDEP). We have studied ECG changes during 61 complex partial seizures of temporal lobe origin in 20 patients. Tachycardia was observed in 24/61 (39%) and bradycardia in 3/61 (5%). The mean and median tachycardia rate was 139 and 140 beats/min (range 120-180). The longest R-R interval observed was 9 seconds. No difference was found in regard to the lateralisation of seizures and cardiac arrhytmia. One of the patients with bradycardia was fitted with a demand cardiac pacemaker, which appeared to decrease the number of his falls. In conclusion, ictal cardiac changes which may be seen in temporal lobe epilepsy (TLE) are sinus tachycardia and occasionally sinus bradycardia. Patients presenting vague complains suggestive of either TLE or cardiac dysrhythmia, simultaneous monitoring with EEG/ECG is required, and if the episodes are frequent, video-EEG should be considered. Further studies on this subject are warranted as this may shed some light on possible mechanisms for SUDEP.

Adolescent↗
PubMed1995

Myoclonic epilepsy of late onset in trisomy 21.

We report the case of a patient with trisomy 21 (T21) with late onset epilepsy. The electroclinical features were of myoclonic jerks on awakening and generalised tonic clonic seizures, with generalised spike and wave on EEG, and a progressive dementia. As familial Alzheimer's dementia and progressive myoclonic epilepsy (Unverricht-Lundborg type) are both linked to the chromosome 21, this case may represent a distinct progressive myoclonic epilepsy related to T21.

Down Syndrome↗
PubMed1994

[Preliminary analysis of factors causing mental retardation in China].

Analysis of the data collected from national sampling survey of the mental retarded in 1987 showed: (1) prevalence of mental retardation in China was 12.68/1,000, (2) its causes mainly included hereditary diseases, cerebral diseases, malnutrition, pregnant infection and birth trauma for children and senile dementia for the elderly aged 60 or over, (3) severe mental retardation was mainly caused by cerebral diseases and developmental deformity in the country, and (4) the causes for 40.1% of the mental retarded persons remained unknown. Based on the researches at home and abroad, a series of major preventive measures for mental retardation have been put forward, they included: (1) to promote better birth and better rearing, vaccination, proper nutrition for pregnant mothers and infants, and safety education as focuses in primary prevention, (2) to detect early and timely treat cerebral diseases and nutritional deficiency, to strengthen antenatal diagnosis and early screening for inborn metabolic diseases as secondary prevention, and (3) to strengthen education, behavioral training and psychological rehabilitation, and to provide community-based rehabilitation service for the mental retarded as tertiary prevention.

Adolescent↗
PubMed1993

Effects of different doses of norethisterone on ovarian function, serum sex hormone binding globulin and high density lipoprotein-cholesterol.

The ovarian effects of different doses of norethisterone (NET) were compared in 45 normally menstruating women in order to find the lowest effective dose of the Chinese NET "visiting pill". Subjects were randomly divided into 3 groups. Each subject in each group was taking 0.5, 1.5 or 3.0 mg per day from days 5 to day 18 of the cycle. Blood samples were taken on days 5, 8, 11, 14, 17, 20, 23, 26 and 29 of the cycle. Serum oestradiol (E2), progesterone (P), sex hormone binding globulin (SHBG), high density-lipoprotein cholesterol (HDL-C), and NET concentrations were measured. Ovulation, delayed ovulation, ovulation inhibition and follicular activity were classified by the analysis of the peripheral serum levels of sex hormones. Ovulation occurred in 7 women in the 0.5 mg group, in 2 women in the 1.5 mg group and in none of the 3.0 mg group. Mean serum SHBG levels were reduced progressively by 6.6% (Group 0.5), 15.5% (Group 1.5) and 23.4% (Group 3.0). There were no significant changes in HDL-C levels in any group. There was a significant correlation of mean serum NET concentrations with dose. The lack of complete inhibition of ovulation in most women in the 1.5 mg and 0.5 mg groups might suggest that the dose of NET required when used as a visiting pill could not be reduced below 3.0 mg.

Adult↗