Biomedical subjects

C L Lin

Publications and source records attributed to C L Lin.

At least 91 records · Page 5Linked to original sources

PubMed1999

Spontaneous intracerebral hemorrhage in children.

We reviewed our experience in 42 children younger than 16 years with spontaneous intracerebral hemorrhage (ICH) treated between January 1989 and December 1997. Glasgow coma scale (GCS) on admission was 15 in 21 (50%) patients. The most frequent presenting symptoms were headache in 28 (67%) patients, followed by loss of consciousness in 22 (52%) patients and vomiting in 21 (50%) patients. Three cases were diagnosed initially as meningitis and two cases as common cold. The locations of ICH were lobar (26 patients) and cerebellar (7). Cerebral angiographies were performed on 28 patients, and were diagnostic in 19 (68%). Magnetic resonance imaging (MRI) scans revealed two cases of cavernous angiomas, which were confirmed by the pathologic studies of surgical specimens. Laboratory examinations detected two cases of acute leukemia. Four categories of the causes of ICH were determined in 23 (55%) patients. The leading cause of bleeding was arteriovenous malformations (AVMs). The in-hospital survival rate of all patients in this study was 79%. Patients with GCS 3-5 on admission and ICH located at brain stem, cerebellum, and multiple subcortical areas had higher mortality rates. On the follow-up (mean 42 months), seventy percent of our cases had made a good recovery, 21% a fair recovery, 3% a poor recovery, and 6% had died. Children with ICH recover motor function more rapidly than adults. However, visual deficits always persist at our long-term follow-up examinations. A physician should keep in mind the diagnosis of ICH in children, even though the presenting symptoms may be non-specific and the incidence of ICH is very low in children.

Adolescent↗

PubMed1999

Attenuation of basilar artery spasm after experimental subarachnoid hemorrhage in rabbit by potassium channel activator cromakalim--a preliminary result.

Cerebral vasospasm associated with aneurysmal subarachnoid hemorrhage (SAH) remains a major complication in patients suffering from SAH. Regulation of membrane potential of arterial smooth muscle through activation or inhibition of potassium (K+) channel activity provides an important mechanism to dilate or constrict arteries. The present study examined the effect of a K+ channel activator, cromakalim, on cerebral vasospasm following experimental SAH. By the route of topical application and intra-arterial injection, basilar arteries were exposed transclivally and measured on-line using videomicroscopic camera. Continuous microinjection from right vertebral artery was given after the result of application was observed. Basilar artery spasm induced by SAH was released by topical or intra-arterial administration of cromakalim, and this beneficial effect against cerebral vasospasm was dose-dependent. There was no significant difference between topical and intra-arterial administration of cromakalim. These results indicate that K+ channel activator may play an important role for ameliorating cerebral vasospasm. An important goal of future studies will be to carefully evaluate the possibility and effect of intra-arterial administration of cromakalim to treat angiographic vasospasm.

Animals↗

PubMed1999

Prognosis of spontaneous intracerebral hemorrhage in hemodialysis patients.

During an 8-year period, 32 consecutive patients with chronic renal failure on maintenance hemodialysis were diagnosed to have cerebral hemorrhage. The outcome was determined using the activity of daily life (ADL) at 6 months after hemorrhage. The overall mortality was 64%. Of the 12 surviving patients, no one made a good recovery (back to normality), 5 recovered to ADL grade II, 4 to grade III, 1 to grade IV, and 2 to grade V. Up to 91% of the patients had a history of hypertension. On admission, Glasgow coma scale (GCS) was 15 in 8 cases, 8-14 in 10, and below 8 in 14. The poor prognostic factors showing statistical significance included a poor admission GCS, age above 65 years, and blood sugar level of more than 200 mg/dl. Other factors which apparently were not related to the outcome included sex, history of stroke, acute myocardial infarction, hypertension, and diabetes mellitus, the locations of hemorrhage, the duration of hemodialysis, treatment modality (surgery vs non-surgery), and the laboratory data (blood urea nitrogen, creatinine, platelet count, hemoglobin, prothromin time, and partial thromboplastin time). This study confirmed a poor prognosis for hemodialysis patients with cerebral hemorrhage. More attention should be paid to the control of blood sugar in this group to improve the outcome of cerebral hemorrhage in hemodialysis patients, especially in elderly patients with poor admission GCS.

Adult↗

PubMed1999

Cardiogenic shock in a patient with glyphosate-surfactant poisoning.

We present a case of glyphosate-induced cardiogenic shock in a young man. The patient a 26-year-old man, presented with nausea and vomiting 4 hours after attempting suicide by drinking 150 mL of glyphosate surfactant. Cardiogenic shock with accelerated idio-ventricular rhythm on electrocardiography developed after admission. Intravenous injection of epinephrine, atropine, and calcium failed to improve the condition. Over the next 16 hours, the QRS complex gradually narrowed, sinus rhythm returned, and the hemodynamic status improved. Echocardiograms revealed diffuse left ventricular hypokinesis with markedly reduced ejection fraction while the patient was in shock; normal left ventricular function resumed the next day. In this case, the glyphosate surfactant poisoning-induced shock may have been due to transient suppression of the cardiac conduction system and contractility, rather than intravascular hypovolemia.

Adult↗

PubMed1999

Obstructive hypertrophic cardiomyopathy in Taiwanese adults.

The purpose of this study was to analyze the clinical profiles, echocardiographic findings, and mortality among adult Taiwanese patients with obstructive hypertrophic cardiomyopathy (HCM) at Chang Gung Memorial Hospital, a university-affiliated tertiary referral center in suburban Taipei. We reviewed the medical records of all adult (> 15 years of age) patients referred to our laboratory for echocardiographic examinations of cardiac diseases from May 1990 through December 1996. The diagnosis of obstructive HCM required an outflow gradient of above 10 mm Hg and the presence of asymmetric septal hypertrophy of the left ventricle. Follow-up information on was obtained from hospital records, questionnaires, interviews, or the National Death Certificate Registry. Of the 6.798 adults who underwent echocardiographic examinations during the study period 122 (1.79%) had obstructive HCM. The mean +/- standard deviation age of the patients was 62.2 +/- 12.6 years, and females predominated (n = 76, 62.3%). During the mean follow-up period of 3.2 years, the annual all-cause mortality rate was 4.7%. Most deaths were due to concurrent medical conditions. The annual cardiac mortality rate was 0.99%. Logistic regression analysis identified medication with calcium channel blockers as the only negative predictor (relative risk = 0.26, 95% confidence interval = 0.07-0.96) of all-cause mortality, and left atrial size as the only positive predictor (relative risk = 1.18, 95% confidence interval = 1.02-1.37) of cardiac mortality. Cox regression analysis confirmed the former association, but not the latter. Thus, in our institution, obstructive HCM had a low prevalence among adult patients referred for echocardiographic examination. These patients were elderly and often had other associated medical conditions. The high all-cause mortality rate was largely due to non-cardiac causes. These findings suggest that obstructive HCM tends to have a benign clinical course. Large atrial size could be an independent predictor of cardiac mortality, but this possibility requires further confirmation.

Aged↗

PubMed1998

Molecular cloning and expression of the rat EAAT4 glutamate transporter subtype.

Glutamate transport is a primary mechanism for the synaptic inactivation of glutamate. Excitatory amino acid transporter 4 (EAAT4) is a novel glutamate transporter with properties of a ligand-gated chloride channel that was recently cloned from human brain. Here we report the cloning of rat EAAT4 (rEAAT4) cDNA from rat cerebellum. The nucleotide sequence of rEAAT4 was 88% identical to the human sequence, and the predicted peptide was 89% identical to the human protein. The transport activity encoded by rEAAT4 has high affinity for L-glutamate. In Xenopus laevis oocytes expressing rEAAT4, L-glutamate and other transporter substrates elicited a current predominantly carried by chloride ions. Like human EAAT4, the rEAAT4 mRNA was largely restricted to cerebellar Purkinje cells; the rEAAT4 protein was localized to Purkinje cell somas and dendrites.

Amino Acid Transport System X-AG↗

PubMed1998

Arachidonic acid activates a proton current in the rat glutamate transporter EAAT4.

The excitatory amino acid transporter EAAT4 is expressed predominantly in Purkinje neurons in the rat cerebellum (1-3), and it participates in postsynaptic reuptake of glutamate released at the climbing fiber synapse (4). Transporter-mediated currents in Purkinje neurons are increased more than 3-fold by arachidonic acid, a second messenger that is liberated following depolarization-induced Ca2+ activation of phospholipase A2 (5). In this study we demonstrate that application of arachidonic acid to oocytes expressing rat EAAT4 increased glutamate-induced currents to a similar extent. However, arachidonic acid did not cause an increase in the rate of glutamate transport or in the chloride current associated with glutamate transport but rather activated a proton-selective conductance. These data reveal a novel action of arachidonate on a glutamate transporter and suggest a mechanism by which synaptic activity may decrease intracellular pH in neurons where this transporter is localized.

Amino Acid Transport System X-AG↗

PubMed1998

Dendritic cell chemotaxis and transendothelial migration are induced by distinct chemokines and are regulated on maturation.

The capacity of dendritic cells (DC) to initiate immune responses is dependent on their specialized migratory and tissue homing properties. Chemotaxis and transendothelial migration (TEM) of DC were studied in vitro. Immature DC were generated by culture of human monocytes in granulocyte-macrophage colony-stimulating factor and IL-4. These cells exhibited potent chemotaxis and TEM responses to the CC chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, RANTES, and monocyte chemotactic protein-3, and weak responses to the CC chemokine MIP-3beta and the CXC chemokine stromal cell-derived factor (SDF)-1alpha. Maturation of DC induced by culture in lipopolysaccharide, TNF-alpha or IL-1beta reduced or abolished responses to the former CC chemokines but markedly enhanced responses to MIP-3beta and SDF-1alpha. This correlated with changes in chemokine receptor expression: CCR5 expression was reduced while CXCR4 expression was enhanced. These findings suggest two stages for regulation of DC migration in which one set of chemokines may regulate recruitment into or within tissues, and another egress from the tissues.

Cell Differentiation↗

PubMed1998

Mutations in the glutamate transporter EAAT2 gene do not cause abnormal EAAT2 transcripts in amyotrophic lateral sclerosis.

Recently, variant mRNA transcripts for the astroglial glutamate transporter EAAT2 have been detected in brain tissues of 60% of patients with sporadic amyotrophic lateral sclerosis (SALS). We have tested the hypothesis that the gene for EAAT2 may be defective in some ALS cases. In 16 familial ALS (FALS) pedigrees without mutations in SOD1, we failed to detect genetic linkage to the EAAT2 locus. We next characterized the genomic organization of the EAAT2 gene and used single-strand conformation polymorphism analysis of genomic DNA to identify one novel mutation in a single SALS patient and two novel mutations in 2 affected FALS siblings. In the SALS patient, the mutation substitutes serine for an asparagine that might be involved in N-linked glycosylation of the EAAT2 protein. In the 2 affected individuals in the FALS family, we detected both a mutation in the 5' end of intron 7 and a silent G --> A transition at codon 234 in exon 5. It remains unclear whether this intron 7 mutation is related to the defective mRNA splicing. These studies indicate that germline mutations in the EAAT2 gene are infrequent and do not explain the presence of variant mRNA transcripts of EAAT2 in more than one-half of ALS cases.

Amyotrophic Lateral Sclerosis↗

PubMed1998

Anorectal function and endopelvic dissection in patients with repaired imperforate anus.

Fifty-eight patients with anorectal malformations were closely followed up for postoperative anorectal function. Constipation was noted shortly after anorectoplasty in 10 of 28 low anomalies (35.7%) treated with limited sagittal anorectoplasty (LSARP), in 18 of 25 high or intermediate anomalies (72.0%) treated with posterior sagittal anorectoplasty (PSARP), but in none of 5 high or intermediate anomalies treated with Rehbein's mucosa-stripping endorectal pull-through and anterior sagittal perineal anorectoplasty (R-ASAP). The constipation resolved mostly within 1-2 years after repair under conservative management, but persisted beyond 2 years after repair in 3/25 children with LSARP and 10/25 with PSARP. Anal soiling was noted in 1/23 (4.3%) LSARP and 6/22 (27.3%) PSARP patients, but normal anorectal function was attained in 20/23 LSARP (86.9%) and 11/12 PSARP patients (50.0%) by the time of toilet training. Manometric studies disclosed that the resting rectal pressure (RRP) was lower and the anorectal pressure gradient (ARPG) higher in the constipated than the non-constipated children, while the RRP was higher and the ARPG lower in the soiled than the non-soiled patients. The ARPG after R-ASPA was close to that of non-constipated and in between that of the constipated and soiled patients. The rectoanal sphincter inhibitory reflex was not related to defecation status or surgical procedures, but showed a tendency toward positive conversion with time or after exclusion of esctatic terminal bowel in the severely constipated. It is concluded that anorectal function in patients with repaired imperforate anus seems to be more affected by the extent of endopelvic dissection than by preservation of the terminal bowel or sphincter muscles.

Anal Canal↗

PubMed1998

Aberrant RNA processing in a neurodegenerative disease: the cause for absent EAAT2, a glutamate transporter, in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is characterized by selective upper and lower motor neuron degeneration, the pathogenesis of which is unknown. About 60%-70% of sporadic ALS patients have a 30%-95% loss of the astroglial glutamate transporter EAAT2 (excitatory amino acid transporter 2) protein in motor cortex and spinal cord. Loss of EAAT2 leads to increased extracellular glutamate and excitotoxic neuronal degeneration. Multiple abnormal EAAT2 mRNAs, including intron-retention and exon-skipping, have now been identified from the affected areas of ALS patients. The aberrant mRNAs were highly abundant and were found only in neuropathologically affected areas of ALS patients but not in other brain regions. They were found in 65% of sporadic ALS patients but were not found in nonneurologic disease or other disease controls. They were also detectable in the cerebrospinal fluid (CSF) of living ALS patients, early in the disease. In vitro expression studies suggest that proteins translated from these aberrant mRNAs may undergo rapid degradation and/ or produce a dominant negative effect on normal EAAT2 resulting in loss of protein and activity. These findings suggest that the loss of EAAT2 in ALS is due to aberrant mRNA and that these aberrant mRNAs could result from RNA processing errors. Aberrant RNA processing could be important in the pathophysiology of neurodegenerative disease and in excitotoxicity. The presence of these mRNA species in ALS CSF may have diagnostic utility.

Amyotrophic Lateral Sclerosis↗

PubMed1998

Systemic administration of the potassium channel activator cromakalim attenuates cerebral vasospasm after experimental subarachnoid hemorrhage.

OBJECTIVE: Cerebral vasospasm is a primary complication after aneurysmal subarachnoid hemorrhage (SAH). Recent evidence indicates that the activation of potassium (K+) channels may be of benefit in relieving spastic constriction. The present study examined the effects of systemic administration of a K+ channel activator, cromakalim, on cerebral vasospasm after experimental SAH. METHODS: Experimental SAH was performed in rabbits by injecting autologous blood into the cisterna magna. Intravenous injections of cromakalim or vehicle were administered twice daily with the first injection administered 1 hour after induction of SAH. Animals were killed by perfusion-fixation 48 hours after SAH. Basilar arteries were removed and sectioned, and the luminal cross-sectional areas were measured. RESULTS: Experimental SAH induced cerebral vasospasm in untreated and vehicle-treated animals. Cromakalim attenuated cerebral vasospasm in a dose-dependent manner. This effect achieved statistical significance at doses of 0.1 and 0.3 mg/kg. CONCLUSION: These results support the concept that targeting vascular K+ channels can be of benefit in preventing the development of cerebral vasospasm. The findings also indicate that cromakalim represents a potential therapeutic agent for the treatment of cerebrovascular pathophysiology after SAH.

Animals↗

PubMed1998

Effect of ozone treatment on Toxocara canis eggs.

The effect of ozone treatment on the development and viability of Toxocara canis eggs was studied. Despite treatment with ozone, unembryonated T. canis eggs could develop into viable second-stage larvae when assayed by larvae recovery after oral inoculation into mice. The viability of second stage larvae of T. canis was also not affected by ozone treatment. No significant difference was observed in the larvae recovery count and migratory pattern of the ozone-treated larvae and the untreated control because the majority of the larvae were recovered from the liver and lungs on day 2 postinoculation. However, scanning electron microscopy of the ozone treated T. canis eggs showed many blebs on the surface of the protein coat at the basement of the honeycomb-like structures. The honeycomb-like structures on the egg surface were also observed to be distorted after ozone treatment. Thus, in spite of inducing some surface morphological changes on the egg, ozone was observed to have no effect on the viability of the embryonated second stage larvae of T. canis.

Animals↗

PubMed1998

Successful resection of a teratoma of the third ventricle in a 3-year-old boy.

Few cases of teratoma in the third ventricle have been reported in detail. We describe a 3-year-old Chinese boy presenting with increased intracranial pressure, headache, and vomiting. Preoperative computed tomography and magnetic resonance imaging demonstrated a teratoma in the third ventricle. Complete excision of the tumor was achieved through the interhemispheric transcallosal approach. The patient did well and was without neurologic deficits postoperatively. Although the majority of tumors located in the third ventricle are malignant and can penetrate the brain tissues that constitute the wall of the third ventricle, mature teratomas are an exception and total removal may be possible.

Cerebral Ventricle Neoplasms↗

PubMed1998

Familial intracranial aneurysms.

We describe a 53-year-old mother and a her 34-year-old son who suffered from spontaneous subarachnoid hemorrhage (SAH) and/or intracerebral hemorrhage due to a ruptured intracranial aneurysm. Diagnosis of the intracranial aneurysm was made by CT scan of the brain, and cerebral angiography. These two cases received surgical intervention and returned to their previous social activity after discharge, even though the mother had arrived in a comatose condition. The literature is reviewed and the characteristic expressions of familial intracranial aneurysms are described. The etiology of cerebral aneurysms is still uncertain but it is likely multifactorial. For the 176 patients with intracranial aneurysm(s) treated at Kaohsiung Medical College Hospital, the mean age at diagnosis was 51.9 years and these aneurysms were distributed mainly at the internal carotid artery (43.8%) and the anterior communicating artery (33.5%). The familial aneurysms tend to rupture at a younger age, occur less often at the anterior communicating artery and more often at the internal carotid artery and the middle cerebral artery as compared with that of non-familial aneurysms. In siblings, aneurysms occur at identical sites or at mirror sites and rupture within the same decade of life twice as frequently as expected in non-familial aneurysm cases. The familial aggregation of intracranial aneurysms and the above characteristic expressions suggest that heredity may play a role in some familial aneurysms. The pattern of inheritance, however, has not been established. Screening examinations and the treatment of unruptured intracranial aneurysms in asymptomatic relatives of the familial cases are also discussed.

Adult↗

PubMed1998

Surgical outcome of hypertensive putaminal hemorrhage in patients older than 65 years.

There is no consensus of opinion on the treatment of hypertensive putaminal hemorrhage (HPH), especially in patients older than 65 years. The purpose of this study was to study the surgical outcome of HPH in patients older than 65 years while considering mortality and activity of daily life. Among eighty-three patients aged 65 or older with HPH, fifty-one patients received only medical treatment and 32 were operated upon to remove the hematoma. Each patient was measured by the intracerebral hemorrhage-intracranial hemorrhage grading scale (ICH Grade) which used the sum of eye opening and motor response scores derived from Glasgow Coma Scale. The cubic content of the HPH was calculated from measurement of maximum width (X), length (Y) and height (Z), and the hematoma volume taken as 1/2 that volume (X. Y. Z/2). The acute mortality in surgically treated group was 40.6% and three patients died during the follow-up period from one to six months after the operation. Determinant for the prognosis was the ICH grade and the volume of the hematoma. Patients who returned to ADL 1 and 2 (good recovery) after surgical treatment were 40.0% in ICH Grade I, 16.7% in ICH Grade II, and 20.0% in ICH Grade III. Among those patients who were in ICH Grade IV, none had good recovery. The acute mortality was zero in ICH Grade I, 16.7% in ICH Grade II, 40.0% in ICH Grade III, and 62.5% in ICH Grade IV. The crucial size was 60 ml with a mortality of 77.8% for hematomas larger and 39.1% for hematomas smaller than that. From our lim ited experience, we learned that operation in elderly patients with HPH was considered only in patients with hematomas between 20 to 60 ml, with a high operative mortality and only one-fourth having a good recovery postoperatively.

Aged↗

PubMed1998

Surgical outcome of anterior communicating artery aneurysms.

During a 6-year period, 65 consecutive patients who had undergone anterior communicating artery aneurysmal surgery were reviewed at a follow-up examination from 6 to 78 months (mean 35 months) after operation. On admission 69% of cases had a good Hunt and Hess scale (grades I to II) and 31% a poor grade (grades III to V). The degree of subarachnoid hemorrhage (SAH) was determined by Fisher's grade. Sixteen (25%) patients were classified in grades I and II. Forty-six percent of cases had pre-existing hypertension. Early surgery (within the first three days after the bleeding) was performed in 17% of cases. Intraoperative rupture of aneurysm occurred in six (9.2%) patients. Symptomatic cerebral vasospasm was diagnosed in 14 (22%) cases, but only 8 (12%) had evidence of low density on the computerized tomographic scan. Hydrocephalus developed in 16 (25%) cases and 10 needed ventriculoperitoneal shunting. The outcome was determined using the activity of daily life. Sixty-five percent of the patients made a good recovery and 13.8% died. The significant poor prognostic factors included a poor pre-operative grade of the Hunt and Hess scale, the presence of symptomatic cerebral vasospasm, and the Fisher's SAH grade of greater than II. Other factors which apparently were not related to the outcome included age, sex, timing of surgery, history of hypertension, intraoperative rupture, and the development of hydrocephalus.

Adult↗

PubMed1998

Outcome of spontaneous subarachnoid hemorrhage of unknown etiology.

During a 7-year period, 56 patients with a verified subarachnoid hemorrhage (SAH) in whom neuroradiological investigations failed to reveal a reasonable cause of the bleeding were evaluated. Forty-six patients who survived the SAH were interviewed at a follow-up examination from 10 to 82 months (mean 37 months) after the bleeding. Early prognosis of an unfavorable outcome was possible on the basis of two clinical variables: the poor Glasgow coma scale (GCS < = 11) at admission and the Fisher's SAH grade of greater than II on brain computerized tomographic scans. Other clinical variables in the acute stage, including age, sex, a history of hypertension and the complications of SAH, such as vasospasm, hydrocephalus, and rebleeding, were not related to the early outcome. GCS on discharge was predictive of activity of daily life at follow-up review. On the follow-up, 80% of the patients experienced a good recovery. Rebleeding episode occurred in a patient 5 years after the bleeding. The overall rebleeding rate was 2.2% (equivalent to an annual recurrence of 0.7%). This study confirmed a good prognosis for patients with SAH of unknown cause. We recommend that after thorough panangiography, those patients with SAH of unknown etiology should be encouraged to return to a normal life style without any restriction.

Activities of Daily Living↗