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Biomedical subjects

T H Nguyen

Publications and source records attributed to T H Nguyen.

122 records · Page 7Linked to original sources
PubMed1980

[First trimester termination of pregnancy. The value of treating the cervix pre-operatively in the primigravid patient by extra-amniotic administration of a single dose of F2-alpha prostaglandin gel (author's transl)].

The authors have tried "priming" the cervix by the administration of a single extraamniotic dose of a F2-alpha prostaglandin gel. This is shown to decrease the risks of trauma associated, with the often difficult, instrumental dilatation of a primigravid cervix at the time of the termination of a 9-12 week pregnancy. The dilatation observed at curettage after this single dose was on the average 10.5 mm +/- 2.2 mm. This is very significantly (p < 0,0001) different from that of patients who received a placebo gel, in which the average diameter of the cervical canal was 4.5 mm +/- 1.0 mm. Constituting a sure and safe method this single priming dose is only applicable when the pain, from the uterine contractions that it produces, can be controlled in an efficient manner. The comparisons made concerning this point, in this paper, show that it can only be done by the use of a continuous epidural anaesthetic. This obviates the necessity of another anaesthetic at the time of aspiration-curettage.

Abortion, Induced↗
PubMedDate not supplied

Single dose artemisinin-mefloquine treatment for acute uncomplicated falciparum malaria.

For the treatment of patients with acute falciparum malaria, the combination of artemisinin as a single dose with a single dose of mefloquine was studied in 4 separate prospective trials, comprising 405 adults and 139 children with uncomplicated falciparum malaria in 2 in-patient and 2 rural out-patient studies in Viet Nam. Adults received oral artemisinin and children artemisinin suppositories. Randomized comparative treatment schedules were: artemisinin alone for 5 d, mefloquine-sulfadoxine-pyrimethamine (MSP), or quinine plus sulfadoxine-pyrimethamine (SP). Parasite clearance times (PCT) were rapid for artemisinin treated inpatients (90%: 14.8-20.4 h) but also for patients receiving MSP (PCT 90%: 18.0 h) and quinine (PCT 90%: 22.5 h). The recrudescence rate (RI) during a 28 d follow-up period among the patients given artemisinin plus mefloquine was 15% in the adult in-patients and zero in the adult and children out-patients. RI in the artemisinin 5 d treatment group was 33.3%; among those given artemisinin plus SP it was 47.3% in in-patients and in out-patients 46.1%. In the MSP treated out-patients RI was 1.5% in adults and zero in children. Artemisinin as a single dose (oral in adults and as a suppository in children) in combination with mefloquine was effective in rapidly lowering parasitaemia and in preventing recrudescence in hospital in-patients and in out-patients attending a rural health clinic. MSP alone as a single dose also rapidly reduced parasitaemia (but not as quickly as the artemisinin-mefloquine combination in out-patient children) and prevented recrudescence.

Acute Disease↗
PubMedDate not supplied

Mapping somatosensory evoked potentials to finger stimulation at intervals of 450 to 4000 msec and the issue of habituation when assessing early cognitive components.

Somatosensory evoked potentials (SEPs) to mild electric stimulation of two fingers of the left hand were studied at regular interstimulus intervals (ISIs) of 450, 800, 1400, 2500 and 4000 msec. Habituation was evaluated while the subject was reading a novel so as to virtually ignore the finger stimuli while maintaining steady vigilance levels. Brain SEPs recorded from 25 scalp electrodes were assessed by scatter displays, electronic subtraction, bit-mapped potential fields, and by calculating the Z estimator and dilation factor. Similar results were obtained with randomly varying ISIs. The P14 farfield and cortical N20 did not change with ISIs. The parietal P27-P45 decreased at ISIs of 800 and 450 msec, but showed no significant habituation at ISIs of 1400, 2500 or 4000 msec. This validated the control conditions used for assessing the early cognitive P30 and P40 to attended target stimuli. The frontal N30 also decremented the shorter ISIs but still habituated up to ISIs of 2500 msec. The clear dissociation between frontal N30 and parietal P27 at the larger ISIs suggests that they involve at least in part distinct neural generators.

Adolescent↗
PubMedDate not supplied

Genetic and molecular studies of macular dystrophies: recent developments.

Macular degeneration is a heterogeneous group of disorders characterized by progressive central visual loss and degeneration of the macula and underlying retinal pigment epithelium (RPE) of the eye. Age-related macular degeneration (ARMD), the most common form of the disease, is the leading cause of legal blindness in the elderly population in the United States and in the many developed countries throughout the world. Despite its prevalence, its etiology and pathogenesis are poorly understood, and effective treatment options are limited for most patients. Inherited macular dystrophies share many important features with ARMD but are more readily studied by molecular genetic approaches. Over the past few years, significant progress has been made in the molecular genetics of inherited macular dystrophies. Genes responsible for dominant and recessive Stargardt's macular dystrophy as well as Best's disease have been localized to specific chromosomal regions. The peripherin/RDS gene when defective is associated with butterfly-shaped pattern dystrophy. Molecular studies of genes involved in macular dystrophies may yield insights into the mechanisms of pathogenesis of macular degeneration and provide new rationale for the management and treatment of patients with these diseases.

Base Sequence↗
PubMedDate not supplied

The impact of dengue haemorrhagic fever on liver function.

The impact of dengue haemorrhagic fever (DHF) on liver function was studied by measuring serum transaminase levels on 45 patients with DHF confirmed by virus isolation and serodiagnosis in 1995. Abnormal levels of AST and ALT were observed in 97.7 and 37.3% of the patients, respectively. The fact that the level of AST was higher than that of ALT and that the elevation of transaminases was mild to moderate in most cases (< 5-fold greater than the normal upper limit for AST and ALT) showed that liver involvement was also mild to moderate in most cases of DHF. The results of transaminases did not differ significantly between cases with and without hepatitis B or hepatitis C virus infection, nor between primary and secondary cases of infection, but a significantly higher elevation of AST and ALT was observed in DHF patients with gastrointestinal haemorrhage. Two patients with dengue encephalopathy (in 1992) and one patient with dengue encephalopathy who died of massive gastrointestinal haemorrhage (in 1995) had unusually high transaminase levels as a sign of acute liver failure. It is concluded that DHF may cause mild to moderate liver dysfunction in most cases; only some patients may suffer from acute liver failure leading to encephalopathy and death.

Alanine Transaminase↗
PubMedDate not supplied

Diurnal variation in synaptic ribbon length and visual threshold.

Previous work suggests that photoreceptor synaptic ribbon length and absolute dark-adapted threshold may vary during a 24-h diurnal cycle. To test this hypothesis, we examined the length of photoreceptor synaptic ribbons and the dark-adapted threshold in black (+/+) and albino (c2J/c2J) C57BL/6J mice at six times over a 24-h period. Testing began 2 h after light onset (ZT 2:00) and continued at successive 4-h intervals (12 h:12 h light:dark). We determined the length of the synaptic ribbons in frozen sections by labeling them with an antibody specific for synaptic ribbons. Synaptic ribbons vary in length at different points in the diurnal cycle in both types of mice, but the synaptic ribbons in black mice are longer than those in albino mice by an average of 0.33 microm. The synaptic ribbons of black mice also have a larger response to changes in the light cycle. Ribbon length in black mice ranges from 1.66 microm to 1.4 microm, whereas ribbon length in albino mice ranges from 1.32 microm to 1.25 microm. The shortest ribbons are evident 6 h after light onset in both types of mice, whereas the longest ribbons appear within 2 h after light onset. These changes in synaptic ribbon length support the idea that photoreceptor synaptic ribbons are dynamic structures whose length changes over a 24-h diurnal cycle. Examining black and albino mice with a water-maze behavioral assay showed that visual thresholds in black and albino mice vary over the 24-h diurnal cycle. The visual thresholds of albino mice are elevated compared with black mice at all times tested. This is consistent with previous findings of visual thresholds in hypopigmented mice. The lowest threshold (greatest sensitivity) is present 2 h after light onset (ZT 2:00) and corresponds to the time when synaptic ribbons are the longest. The highest threshold is observed 6 h after light onset, the time when synaptic ribbons are shortest. These results show that synaptic ribbon length and visual sensitivity vary together in relation to the time.

Albinism, Oculocutaneous↗
PubMedDate not supplied

Production of trichothecene mycotoxins by Australian Fusarium species.

Australian isolates of Fusarium species were grown on potato dextrose agar. Trichothecenes produced by these species were extracted by ethyl acetate followed by methanol and a silica gel column was used to clean-up the extract. The extracted samples were derivatized by acetylation with trifluoroacetic anhydride and the derivatives analysed by gas chromatography/mass spectrometry (GC/MS). Multiple ion detection was used to trace ions characteristic of the trichothecenes expected to be present. Quantitation of those found was based on a known mass of pentabromophenol that was added as an internal standard. Eight species of Fusarium (nineteen strains) were surveyed, of which three species, F. acuminatum, F. equiseti and F. sporotrichioides, produced the trichothecenes scirpentriol, diacetoxyscirpenol, neosolaniol, HT-2 toxin, T-2 toxin, T-2 tetraol and deoxynivalenol. Wheat samples were inoculated with four different species of Fusarium, F. acuminatum, F. equiseti, F. graminearum and F. sporotrichioides, and in these samples diacetoxyscirpenol, neosolaniol, HT-2 toxin and T-2 toxin were found.

Acetylation↗
PubMedDate not supplied

Anti-phenolic glycolipid-I (PGL-I) determination using blood collection on filter paper in leprosy patients.

The authors studied 70 leprosy patients and 20 normal individuals, comparing the traditional sera collection method and the finger prick blood with the conservation on filter paper for specific antibodies against the native phenolic glycolipid-I (PGL-I) from Mycobacterium leprae. The finger prick blood dried on filter paper was eluated in phosphate buffer saline (PBS) containing 0.5% gelatin. The classical method for native PGL-I was performed for these eluates, and compared with the antibody determination for sera. It was observed that there is a straight correlation comparing these two methods; although the titles found for the eluates were lower than those obtained for serology. This blood collection method could be useful for investigation of new leprosy cases in field, specially in contacts individuals.

Adolescent↗
PubMedDate not supplied

[Epidural metastases at the spinal level. Clinical study of 82 cases].

This is a retrospective review of 82 cases of spinal epidural metastasis. A warning vertebral or radicular pain was present in 85% of the cases. In 33% of the patients, who complained only of pain without any neurological deficit, a complete myelographic block was already present. It is thus of prime importance not to neglect a vertebro-radicular pain in cancer patients, and even in patients without known cancer since the epidural metastasis was the first manifestation of the neoplasm in 30% of our cases. The indications for myelography are defined. The functional result (i.e. ability to walk) after treatment depends on the neurological state before treatment. In our series, total paraplegia was always irreversible. Early diagnosis and treatment are thus very important. The surgical treatment alone is judged insufficient. We were not able to prove the superiority of one of the following therapeutic modalities: laminectomy followed by radiotherapy or radiotherapy alone. Radiotherapy is indicated in all cases, often as the sole treatment. The indications for surgery are defined; they are based on our own experience and the literature. High dose steroids are indicated as adjuvant therapy.

Adolescent↗
PubMedDate not supplied

[A case of primary testicular carcinoid tumor].

Carcinoid tumors are rare and mainly found in the G.I. tractus but also in the tracheobronchial tree and ovaries. The testicular localization, primary or metastatic, is rare. The authors report a primary carcinoid tumor of the testis in a 35 years old male. The tumor characteristics are well enough known from the literature. Primary carcinoid tumors of the testis appear to be of a low grade malignancy. Local therapy suffices for care of the patient as long as, on microscopic examination, it is not an expression of a teratocarcinoma. The diagnosis is made by the discovery of a tumor since the carcinoid syndrome is seldom in the clinical picture (only 2 cases in the literature, one of whom with generalized metastasis).

Adult↗
PubMedDate not supplied

[A case of primary germinoma in the convex part of the brain (author's transl)].

Cerebral germinoma is a rare tumour reported most frequently in the pineal region or the floor of the third ventricle. Localization in the hemispheres may occur. In the reported case the tumour was situated in the right frontoparietal region. In view of the well-known radiosensitivity of germinomas the treatment of choice is radiotherapy. Precise histological diagnosis is therefore cardinally important for deciding on treatment and establishing the prognosis. CAT scanning allows progress to be monitored.

Brain Neoplasms↗
PubMedDate not supplied

Asthma and limitation of activities in Fort Saskatchewan, Alberta.

A study was undertaken to determine the prevalence and impact of asthma in elementary school children in Fort Saskatchewan, Alberta. Questionnaires were distributed at all seven elementary schools and were completed by the parents. Of the 1,457 eligible students in grades one to six, questionnaires were returned for 1,083 (74%). A history of physician-diagnosed asthma was reported for 12.9% of the children: 16.0% of boys and 9.7% of girls. Currently, 9.9% of children had asthma: 11.6% of boys and 8.2% of girls. Compared to children without, those with asthma were more than 10 times as likely to have to limit their activities for a health reason (70.5% versus 6.6%), missed school more often for health reasons (32.7% versus 14.8% missed two or more days in the previous month), reported more "colds" in the previous year and were three times as likely to have had pneumonia. The prevalence of asthma is approximately twice as high as that found in children across Canada and underscores the need to determine risk factors for asthma in this population. The finding that 1 in 10 children had asthma emphasized the need for programs aimed at children with asthma.

Activities of Daily Living↗