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Biomedical subjects

L M Tang

Publications and source records attributed to L M Tang.

At least 19 recordsLinked to original sources
PubMed2000

Transient global amnesia and amaurosis fugax in a patient with common carotid artery occlusion--a case report.

The etiology of transient global amnesia (TGA) is debatable. The hypothesis of a thromboembolic cause of TGA has been questioned by recent case control studies. Occlusion of the common carotid artery (CCA) is rare. Although amaurosis fugax (AF) is a hallmark of ipsilateral internal carotid artery disease, its occurrence in CCA occlusion is less known. Association of these three conditions in a patient may imply pathophysiologic significance. Here, the authors report a 76-year-old man who suffered from a spell of TGA and then several attacks of AF of the right eye. Progressive occlusion of the right CCA was documented by repeat carotid duplex scans and was finally confirmed by cerebral angiography. In this patient, the occurrence of CCA occlusion and AF implicates a vascular etiology for the event of TGA. A noninvasive carotid ultrasonographic screen may, therefore, be worthwhile for patients with TGA.

Aged↗
PubMed1999

Thoracic disc herniation mimicking acute lumbar disc disease.

STUDY DESIGN: Case report of a 49-year-old woman with a lower thoracic disc herniation mimicking acute lumbosacral radiculopathy. OBJECTIVE: To describe an unusual case of thoracic disc herniation mimicking acute lumbar disc disease. SUMMARY OF BACKGROUND DATA: Symptomatic thoracic disc herniation is rare and its clinical manifestations differ widely from those of cervical and lumbar disc herniations. Midline back pain and signs of spinal cord compression progressing over months or years are the predominant clinical features. Acute and subacute thoracic disc herniation occurs in less than 10% of patients, and isolated root pain is unusual. METHODS: A 49-year-old woman had acute low back pain radiation into the left buttock and the lateral aspect of the left leg and left foot. Magnetic resonance imaging study showed a bulging disc and posterior osteophytes at T11-T12. RESULTS: Surgical removal of the herniated disc and osteophytes rapidly relieved her symptoms and neurologic deficits. A follow-up neurologic examination 3 years later showed normal motor and sensory functions, although low back soreness was noted occasionally. CONCLUSION: A case of thoracic disc herniation mimicking an acute lumbosacral radiculopathy is presented. Compression of the lumbosacral spinal nerve roots at the lower thoracic level after exit from the lumbar enlargement may be the mechanism for this unusual presentation.

Acute Disease↗
PubMed1999

Current perception threshold testing in Fabry's disease.

We investigated 16 patients with Fabry's disease (eight hemizygous men and eight heterozygous women) in one family. We used constant current perception threshold (CPT) testing, which evaluated three major sensory nerve fiber populations, to assess subjective complaints of pain and paresthesias. We also examined clinical and biochemical features and compared the values of CPTs and nerve conduction studies (NCS) in detecting the sensory neuropathy. Our results showed that CPT testing at low frequencies (5 and 250 Hz) was significantly more sensitive than at a higher frequency (2 kHz) and NCS in detecting sensory neuropathy in patients with Fabry's disease. However, there was no correlation between CPT testing and clinical symptom scores, duration of disease, creatinine clearance (Ccr) values or alpha-galactosidase A (AGA) activities in either hemizygous or heterozygous patients. Hemizygous patients clinically demonstrated more severe symptom scores, poorer renal function, and higher prevalence of hypohidrosis and corpora angiokeratomas than did heterozygous patients, which indicates that detailed clinical examinations can differentiate the clinical status of hemizygous men from heterozygous women. There were no associations between the biochemical levels of serum AGA activity and renal function (Ccr values) or the symptom scores (grading of acroparesthesia), indicating that biochemical parameters do not predict clinical severity.

Adolescent↗
PubMed1999

MRI in recurrent nasopharyngeal carcinoma.

In this study, we retrospectively reviewed the MRI features of recurrent nasopharyngeal carcinoma (NPC) in 72 patients who underwent MRI before and after gadolinium injection. Recurrent NPC exhibited a high degree of regional spread and a variety of signal intensities and contours. MRI showed a nasopharyngeal mass in 50 patients (69.4 %); other sites of involvement included the parapharyngeal space (44.4 %), nasal cavity (12.5 %), paranasal sinuses (27.8 %), oropharynx (4.2 %), orbit (8.3 %), infratemporal fossa (18.1 %), skull base (59.8 %), intracranial area (51.4 %) and regional lymph nodes (15.3 %). On T2-weighted images, the nasopharyngeal mass gave high signal in 9 of 50 cases (18 %), intermediate in 27 (54 %), mixed in 8 (16 %) and low signal in 6 (12 %). Contrast enhancement was strong in 12 cases (24 %), moderate in 29 (58 %) and heterogeneous in 9 (18 %). The lesion was convex in 31 cases (62 %) and concave or straight in 19 (38 %). Recognition of the distribution and the appearance of recurrent NPC on MRI is essential for timely diagnosis and appropriate treatment.

Adult↗
PubMed1999

Effect of NGF and anti-NGF on neuropathic pain in rats following chronic constriction injury of the sciatic nerve.

The systemic administration of anti-nerve growth factor (NGF) antibodies can prevent local sensory hypersensitivity and block nociceptive fibers from sprouting into denervated adult rat skin. However, in the case of chronic constriction injury (CCI) in a rat, there is evidence that NGF reverses some effects of axotomy and alleviates thermal hyperalgesia. It is with this in mind that we investigated the influence of local anti-NGF and NGF on neuropathic pain and collateral sprouting caused by CCI. In our study, we looked at the effects to the ligated nerves after 30 consecutive days of local injections of anti-NGF and NGF. A high-dose of anti-NGF (1800 ng) was found to eradicate heat and cold hyperalgesia during postoperative days 16-28 and from days 8 to 34 after CCI, respectively. Our results show that a low-dose anti-NGF (18 ng) only mildly alleviates heat hyperalgesia but not cold hyperalgesia. There is evidence that a rebound phenomenon occurs for a short period of time after the anti-NGF injections cease. Results show that anti-NGF injections, whether in a high or low dose, significantly reduces the severity of autotomy or prevents the spread of collateral sprouting from the saphenous nerve into the sciatic innervation territory. In contrast, when a NGF (0.75 ng/g body weight) was applied to the ligated nerve immediately after the ligation, heat and cold hyperalgesia were eradicated during postoperative days 4-68 and from days 4 to 28, respectively. The results show that the effect of anti-NGF is delayed at the onset, is short in duration, and is dependent on the dosage. However, anti-NGF but not NGF blocked collateral sprouting and decreased the severity of autotomy, suggesting that anti-NGF may be a better potential alternative analgesic for the treatment of neuropathic pain in humans. The different initiation times to abolish thermal hyperalgesia by anti-NGF (delayed onset) and NGF (early onset) suggests that alterations in neurotrophic factors contribute to the development of behavioral hyperalgesia via a complex mechanism in CCI rats.

Animals↗
PubMed1999

Olfactory function in patients with nasopharyngeal carcinoma following radiotherapy.

The aim of this study was to examine the impact of radiation treatment on olfactory function in patients with nasopharyngeal carcinoma (NPC). An olfactory function test battery was administered to 25 adult NPC patients having received radiotherapy, 24 adult nasopharyngeal carcinoma patients awaiting to receive radiation treatment, and 36 adult normal control subjects. Members of the three groups were matched in terms of age, educational level, and full-scaled IQ score. Comparing the test results revealed that the NPC patients with radiotherapy had olfactory information processing impairments including absolute threshold, odour-tactile cross-modality matching, verbal identification of odours, and recall and recognition of identity of odours. The deficits of suprathreshold olfactory functioning in these patients did not seem to arise from impaired absolute threshold sensitivity. Provided that the results are reproducible, an evaluation of olfactory functioning in NPC patients during the period of radiotherapy may be useful for detecting or even avoiding side effects of radiation.

Adult↗
PubMed1999

Acute bacterial meningitis in adults: a hospital-based epidemiological study.

Bacterial meningitis, a world-wide disease, has to be reviewed periodically because the specific micro-organisms responsible for the infection vary with time, geography and patient age. To determine its incidence and clinical features in Taiwan, we reviewed the microbiological records for cerebrospinal fluid (CSF) and blood cultures, and the medical records of patients with bacterial meningitis admitted between 1981 and mid-1998. Bacterial micro-organisms were demonstrated in the CSF and/or blood in 395 patients with 418 episodes of bacterial meningitis. Streptococcus species were the most common causative micro-organism group, at 23. 21% of all episodes. Its prevalence rate significantly decreased from the first 7 years of study (41.9%) to the last 10.5 years (19. 2%). However, Klebsiella meningitis and Staphylococcal meningitis were more frequently noted after 1987. More than 70% of patients had at least one underlying disease or condition. Poor prognostic factors indicated by univariable analysis were: age >60 years; diabetes mellitus; severe neurological deficits on the first day of treatment; infection with Gram-negative bacilli; CSF WBC count >5000x10(6)/l; malignancy; seizure; and bacteraemia. The overall mortality rate was 29.4%, 29.7% in the first 7 years of study and 29. 4% in the last 10.5 years. The use of new antibiotics has not reduced the mortality rate in our patients with bacterial meningitis.

Acute Disease↗
PubMed1998

Haemophilus influenzae meningitis in adults.

Haemophilus influenzae meningitis is rare in adults. We reviewed the microbiological records of cerebrospinal fluid (CSF) and blood cultures and the medical records of patients with bacterial meningitis admitted to Chang Gung Memorial Hospital from January 1978 to May 1996. Haemophilus influenzae meningitis was found in six adult patients, accounting for 1.8% of 326 bacteriologically proven adult cases of meningitis diagnosed between January 1984 and May 1996. Predisposing conditions included head trauma and/or neurosurgical procedure in four patients and an extracranial extension of a pituitary adenoma in a diabetic patient. None of them had altered consciousness on the day of treatment. A CSF cell count less than 500 x 10(6) leukocytes/liter was noted in three patients. Antibiotic therapy was successful in all patients. Thus, predisposing conditions, particularly head trauma and/or neurosurgical procedure, are commonly present in adult patients with H. influenzae meningitis. Patients with the infection may have a low cellular count in the CSF that may be readily misinterpreted as meningitis caused by other pathogens.

Adult↗
PubMed1998

Neuropsychological function in patients with nasopharyngeal carcinoma after radiotherapy.

A neuropsychological test battery was administered to 27 adult patients with nasopharyngeal carcinoma (NPC) who had received radiotherapy, 28 adult patients with NPC awaiting radiotherapy, and 35 normal adult controls. The 27 patients with radiotherapy had a conventional dosage, 220 cGy per fraction, or less. The median interval between the completion of radiotherapy and the evaluation of neuropsychological function was 1.7 years. Groups were matched for age and educational level. The results showed that our NPC group with radiotherapy had neuropsychological impairments in the areas of auditory attention/concentration, immediate and delayed verbal recall and immediate visual recall, and recent memory, higher-order visuospatial abilities, and bimanual dexterity. Thus neuropsychological dysfunction may occur in patients with NPC within the first 2 years after radiotherapy.

Adult↗
PubMed1998

Cervical ecchordosis physaliphora: CT and MR features.

We report a case of cervical ecchordosis physaliphora in an elderly man who presented with hemihypoaesthesia and contralateral hemiparesis. MRI showed a well defined, non-enhancing extradural mass lesion on the dorsal surface of the odontoid process of the axis. The lesion was of intermediate signal intensity on T1 weighted images and of low signal intensity on T2 weighted images. CT showed a small bony defect on the adjacent cortex of the odontoid process. Recognition of the imaging features of ecchordosis physaliphora is helpful in suggesting the diagnosis and differentiating the lesion from chordoma.

Aged↗
PubMed1998

Extent of collateral sprouting of intact nerve fibers in rats depends on the local availability of nerve growth factor.

We investigated the influence of local administration of anti-nerve growth factor (NGF) serum on collateral nerve fiber sprouting caused by chronic constriction injury (CCI) of the sciatic nerve in rats. CCI was induced in adult Sprague-Dawley rats (six per group) by constriction of the sciatic nerve of the right hind limb. Control rats received no further manipulation. In four other groups, rabbit preimmune (control) serum or low (18 ng) or high (1800 ng) doses of anti-NGF serum were injected into the operated or unoperated hind limb each day for 1 month. We used an Evans dye-labeled plasma extravasation technique to visualize the extent of collateral sprouting. Local injection of anti-NGF serum at both high and low doses, but not control serum, significantly reduced the spread of collateral sprouting from the saphenous nerve into the sciatic nerve innervation territory. High-dose anti-NGF serum did not block collateral sprouting when injected into the contralateral (unoperated) hind limb, indicating that the inhibition of sprouting was not caused by a systemic effect. In conclusion, local administration of anti-NGF serum can block sprouting of collateral fibers after nerve injury. Our findings suggest that collateral sprouting is dependent on the local availability of NGF to nearby intact cutaneous nerve fibers.

Animals↗
PubMed1997

Myasthenia gravis and Charcot-Marie-Tooth disease type 1A: an unusual combination of diseases.

Concurrence of myasthenia gravis (MG) and Charcot-Marie-Tooth type 1 (CMT1A) neuropathy is rare. We describe a 60-year-old woman with MG and genetically proved CMT1A. The fluctuating ocular symptoms and proximal limb weakness were markedly improved by pyridostigmine treatment. Recognition of the possible association of MG and CMT1A in the same patient is important because the therapeutic result is rewarding.

Charcot-Marie-Tooth Disease↗
PubMed1997

Nasopharyngeal carcinoma: MRI and CT assessment.

Precise assessment of the extent of nasopharyngeal carcinoma (NPC) represents the basic step towards optimal treatment. We compared the capacity of CT and MRI in assessing the extent of NPC in 67 patients. MRI was superior to CT in demonstrating lesions in the retropharyngeal node, skull base, intracranial area, carotid space, longus colli muscle and levator palatini muscle. Of 25 cases in which retropharyngeal adenopathy was recognised only on MRI, seven had been reported as showing oropharyngeal involvement and 18 as primary extension to the carotid space on CT. MRI showed skull-base involvement in 40 patients compared with 27 on CT and intracranial involvement in 38 patients versus 24 on CT. There was not a single case in which skull base invasion was seen on CT but not on MRI. MRI enabled improved recognition of tumour infiltration of longus colli muscles (34 cases compared with 15 on CT). It allowed us to clarify 12 questionable sinonasal opacities on CT. Overall, T-staging was changed in 18 of 67 patients (26.9%), including upstaging in 15 cases and down-staging in 3 cases, after comparing CT with MRI. The nodel status was changed from negative on CT to positive on MRI in 4 of 67 patients (6%). We believe that MRI allows more accurate evaluation of the extent of NPC than CT and should be the primary mode of investigation.

Adolescent↗
PubMed1997

Klebsiella meningitis in Taiwan: an overview.

Klebsiella infection has been considered to be an uncommon cause of meningitis. To determine its incidence and clinical features, we reviewed the microbiologic records of cerebrospinal fluid (CSF) and blood cultures and the medical records of patients with bacterial meningitis admitted between 1981 and 1995. Klebsiella meningitis was diagnosed in 79 patients with 83 episodes. All patients had klebsiella isolated from CSF and/or blood and typical symptoms and signs of acute bacterial meningitis. Of these, 74 were over 16 years of age and 2 of the 5 children were infants. There was an increased prevalence rate of klebsiella meningitis after 1986. Of the 83 episodes, only 9 occurred between 1981 and 1986, accounting for 7.8% of 115 cases with CSF and/or blood culture-proven acute bacterial meningitis, whereas in 1987-95, there were 74 episodes accounting for 17.7% of 419 bacteriologically proven cases. K. pneumoniae accounted for 69 episodes, K. oxytoca, 11 episodes and K. ozaenae, 3 episodes. Male gender, diabetes mellitus and liver cirrhosis were commonly associated with K. pneumoniae meningitis. Neurosurgical procedures were frequently associated with K. oxytoca meningitis. All three patients with K. ozaenae meningitis had a primary disease of the nasopharyngeal pathway. The mortality rate due to K. pneumoniae was 48.5%, K. oxytoca, 10% and K. ozaenae, 0%. In patients with K. pneumoniae meningitis, poor prognostic factors included age over 60 years, diabetes mellitus, bacteremia and severe neurological deficits on the first day of treatment.

Adolescent↗
PubMed1997

Guillain-Barré syndrome in Taiwan: a clinical study of 167 patients.

OBJECTIVE: To identify clinical characteristics of various forms of Guillain-Barré syndrome in Taiwan. METHODS: The clinical and electrophysiological data of 167 consecutive patients with Guillain-Barré syndrome admitted to Chang Gung Memorial Hospital, a general paediatric and adult hospital in Taiwan, were reviewed. RESULTS: Analysis of age distribution disclosed a high incidence (21%) among patients under the age of 10 years. Seasonal preponderance in Spring (March to May) was found. Utilizing clinical and electrophysiological data, these 167 patients with Guillain-Barré syndrome were subclassified; 82 (49%) had acute inflammatory demyelinating polyradiculoneuropathy (AIDP), 32 (19%) had Fisher syndrome (FS), and six (4%) had axonal forms of Guillain-Barré syndrome. The remaining 47 (28%) patients were unclassified. Patients with AIDP and FS had many common clinical features, including seasonal distribution, history of preceding illness, sensory abnormalities, cranial nerve involvement except for extraocular motor nerves, and albuminocytological dissociation on examination of CSF. Follow up study on 145 patients disclosed that 127 (87%) recovered satisfactorily, 14 (10%) were persistently disabled, and four (3%) died during admission to hospital. Clinical features associated with poor outcome (persistent disability or death) were requirement for mechanical ventilation, a low mean compound muscle action potential amplitude (< or = 10% of the lower limit of normal), and age greater than 40 years. CONCLUSION: Guillain-Barré syndrome in Taiwan showed a peculiar age and seasonal distribution and a high frequency of FS not seen in other series. Given that patients with AIDP and FS had many common clinical features, AIDP and FS may have similar underlying pathological mechanisms.

Adolescent↗
PubMed1996

Local application of anti-NGF blocks the collateral sprouting in rats following chronic constriction injury of the sciatic nerve.

Systemic administration of anti-nerve growth factor (NGF) antibodies can block nociceptive fiber sprouting into denervated adult rat skin. However, the effect of local application of anti-NGF on collateral sprouting in rats caused by chronic constriction injury (CCI) has not been well studied. We investigated the influence of local anti-NGF on collateral sprouting caused by CCI of the rat's sciatic nerve. Using a dye-labeled plasma extravasation technique, we can easily evaluate the extent of collateral sprouting by the clearly defined blue coloration area. Our results showed that local application of anti-NGF either in a high or low dose significantly prevented the spread of collateral sprouting from the saphenous nerve into the sciatic innervation territory. In contrast, distilled water did not show a significant block of the saphenous nerve collateral sprouting. Our study suggests that collateral sprouting is dependent on the local availability of NGF by the nearby intact cutaneous nerve fibers.

Animals↗
PubMed1996

Tuberculoma en plaque: CT.

A 35-year-old woman presented with a 6-month history of intermittent headaches, vomiting and dizziness. CT showed a plaque-like mass with tiny calcifications along the surface of the left frontal lobe. The mass exhibited heterogeneous enhancement with a few low-density foci. Underlying sulcal obliteration and enhancement and white matter oedema were also noted. Histopathological examination of excised material was consistent with tuberculoma. Recognition of this unusual presentation of intracranial tuberculoma may facilitate appropriate diagnosis and management.

Adult↗