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Biomedical subjects

M Tran

Publications and source records attributed to M Tran.

51 records · Page 3Linked to original sources
PubMed1994

The acid steatocrit: a much improved method.

The steatocrit method has recently been introduced as a simple screening test for steatorrhea. As it seemed likely that separation of fecal homogenate by centrifugation into a lipid phase, a watery phase, and a solid phase would be pH-dependent, we evaluated the effect of fecal acidification on steatocrit results. We also compared classical and acid steatocrit results in healthy children and in patients with cystic fibrosis and studied the relationship between two steatocrit methods and fecal fat content as measured by a reference chemical method. Steatocrit results increased with the degree of fecal acidification, and maximal results were obtained at the lowest fecal pH values. Means and SEM for classical and acid steatocrit values were 1.1 +/- 0.4% (classical) versus 3.8 +/- 1% (acid) in controls (n = 6) and 5.4 +/- 1.9% (classical) versus 26.9 +/- 4.3% (acid) in cystic fibrosis patients (n = 9). The correlations between fecal fat content measured chemically and steatocrit results were 0.18 (p = 0.35) and 0.81 (p < 0.0001) for classical and acid steatocrit, respectively. We conclude that acidification of fecal homogenates leads to a marked improvement in the steatocrit method.

Celiac Disease↗
PubMed1993

Cholesterol oxidase: a potent insecticidal protein active against boll weevil larvae.

The discovery of proteins that control insects is critical for the continued growth of the agricultural biotechnology industry. A highly efficacious protein that killed boll weevil (Anthonomus grandis grandis Boheman) larvae was discovered in Streptomyces culture filtrates. The protein was identified as cholesterol oxidase (E.C. 1.1.3.6). Purified cholesterol oxidase was active against boll weevil larvae at a concentration (LC50 = 20.9 micrograms/ml) comparable to the bioactivity of Bacillus thuringiensis proteins against other insect pests. Histological studies demonstrated that cholesterol oxidase lysed the boll weevil midgut epithelium, suggesting that this is the primary mechanism of lethality.

Amino Acid Sequence↗
PubMed1993

Central administration of senktide, a tachykinin NK-3 agonist, has an antidiuretic action by stimulating AVP release in water-loaded rats.

Intracerebroventricular (i.c.v.) injections of senktide (0.01-10 nmol), a tachykinin NK-3 agonist, had an antidiuretic action in water-loaded rats (4.5% body wt.). Pretreatment with OPC-31260 (1 mg/kg, i.v.), a non-peptide vasopressin V2 antagonist, inhibited the antidiuretic action induced by exogenous arginine vasopressin (AVP, 0.1 micrograms/kg, i.v.) and senktide (0.1 nmol, i.c.v.). In addition, senktide (11.8 nmol, i.c.v.) caused a marked increase of the plasma AVP level in conscious rats. These results suggest that the central NKB analogue senktide has an antidiuretic effect by stimulating AVP secretion from the pituitary gland through the NK-3 receptor in the hypothalamus.

Animals↗
PubMed1993

Testing the FOCOMETER--A new refractometer.

The FOCOMETER, an optometer which measures spherical refractive errors, is intended to provide rural or economically disadvantaged populations spherical prescriptions without the need for complicated protocols, expensive equipment, or electricity. FOCOMETER readings were compared with the spherical equivalent determined from autorefraction and subjective trial lens refractions in children, and with retinoscopy in adults. Over the range of refractive errors tested (-4 to +5 D) reasonably close readings, within one-half a diopter, were found for comparisons with autorefraction and retinoscopy and about one-tenth of a diopter difference was found between subjective refractions and the FOCOMETER.

Adolescent↗
PubMed1992

(+/-)-3-allyl-7-halo-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepines as selective high affinity D1 dopamine receptor antagonists: synthesis and structure-activity relationship.

Substituted 1-phenyl-3-benzazepines form a class of compounds possessing potent and selective affinity for the D1 DA receptor. 7,8-Dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SKF 38393) and its 6-halo analogues are potent and selective D1 receptor agonists. Recently, the 3-allyl derivatives of SKF 38393 and its analogues were described as selective D1 agonists with higher D1 efficacy and CNS potency. In order to extend these results to compounds in the 7-halo-8-hydroxy-substituted antagonist series, we have synthesized and pharmacologically characterized 3-allyl analogues of 7-substituted (Cl, Br, H) 8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepines. These 3-allyl derivatives were compared with their 3-methyl and 3-unsubstituted analogues in terms of their D1 receptor affinity and selectivity. The results have been used to generate structure-affinity relationships. The D1 receptor affinity, for 3-substitution, is found to be in the order: methyl greater than allyl greater than H. For 7-substitution, the affinity is in the order: Cl = Br greater than H. The 3-allyl compounds show affinity close to that of the parent (3-methyl) compounds while exhibiting a slightly diminished D1 selectivity. However, the greater lipophilicity of the 3-allyl compounds may enable them to cross the blood-brain barrier more readily and thereby exhibit higher in vivo CNS potency. Thus 3-allylbenzazepines have potential as high affinity selective D1 antagonists.

Animals↗
PubMed1992

Herboxidiene, a new herbicidal substance from Streptomyces chromofuscus A7847. Taxonomy, fermentation, isolation, physico-chemical and biological properties.

Screening of microbial fermentation broths for herbicidal activity led to the discovery of a novel polyketide, herboxidiene, from an actinomycete identified as a member of the Streptomyces chromofuscus cluster. A 14- to 20-fold increase in fermentation production of herboxidiene was achieved as a result of media optimization. Herboxidiene was purified using successive reverse phase C18 steps and Sephadex LH-20 chromatography. Its molecular formula, C25H42O6, was determined by HRFAB-MS. Herboxidiene demonstrated exceptionally potent, selective, herbicidal activity against a variety of weed species and was inactive against wheat, even at rates as high as 5.6 kg/hectare.

Culture Media↗
PubMed1991

[Human parvovirus B19 infection during pregnancy. 2 cases].

We report two cases of non immunologic hydrops fetalis associated with intra-uterine human parvovirus B19 (PV B19) infection. The outcome was stillbirth in both cases. Infection by PV B19 was suspected by the presence of intranuclear inclusions in fetal erythroblasts. It was confirmed by the presence of specific immunoglobulins M (IgM) against PV B19 in maternal sera. Intra-uterine infection with human PV B19 is known since 1984; this virus may cause non immunologic hydrops fetalis and stillbirth; teratogenic effects have also been suggested. Epidemiological studies, published in 1988 and 1990 have evaluated the risk of PV B19 fetal related death at 9% and no association was found between infection and congenital anomalies. Subsequent management of infected pregnancies is studied. We emphasize the interest of pathological examination of hydropic stillbirth for this diagnosis.

Adult↗
PubMed1977

Biological effects of high-LET particles on corn-seed embryos in the Apollo-Soyuz Test Project--Biostack III experiment.

High-LET particle hits in embryos of Zea mays corn seeds, flown as part of Biostack III in the Apollo-Soyuz Test Project, were determined via plastic nuclear track detectors. Based on etched particle-track measurements, 41 embryos were hit in seed layer 1 which contained 80 seeds, and 49 hits occurred in layer 2 which contained 79 seeds. The mean LET value and range of atomic numbers of recorded hits is, respectively, 210 +/- 57 keV micrometers -1 and 9 < or approximately Z < or approximately 26. Detailed analysis of one particular seed showing marked growth anomalies revealed two hits in the central region of the embryo. These two hits had LET values in the region of 100-150 keV micrometers-1, and Z > or approximately 20.

Collodion↗
PubMedDate not supplied

PHA production, from bacteria to plants.

The genes encoding the polyhydroxyalkanoate (PHA) biosynthetic pathway in Ralstonia eutropha (3-ketothiolase, phaA or bktB; acetoacetyl-CoA reductase, phaB; and PHA synthase, phaC) were engineered for plant plastid targeting and expressed using leaf (e35S) or seed-specific (7s or lesquerella hydroxylase) promoters in Arabidopsis and Brassica. PHA yields in homozygous transformants were 12-13% of the dry mass in homozygous Arabidopsis plants and approximately 7% of the seed weight in seeds from heterozygous canola plants. When a threonine deaminase was expressed in addition to bktB, phaB and phaC, a copolyester of 3-hydroxybutyrate and 3-hydroxyvalerate was produced in both Arabidopsis and Brassica.

Acetyl-CoA C-Acyltransferase↗
PubMedDate not supplied

Panic disorder among Vietnamese refugees attending a psychiatric clinic: prevalence and subtypes.

This study surveys Vietnamese refugees attending two psychiatric clinics to determine both the prevalence of panic disorder (PD) as well as panic attack subtypes in those suffering PD. A culturally valid adaptation of the SCID-panic module (the Vietnamese Panic Disorder Survey or VPDS) was administered to 100 Vietnamese refugees attending two psychiatric clinics. Utilizing culturally sensitive panic probes, the VPDS provides information regarding both the presence of PD and panic attack subtypes during the month prior to interview. Of 100 patients surveyed, 50 (50%) currently suffered PD. Among the 50 patients suffering PD, the most common panic attack subtypes during the previous month were the following: "orthostatic dizziness" (74% of the 50 panic disorder patients [PDPs]), headache (50% of PDPs), wind-induced/temperature-shift-induced (24% of PDPs), effort-induced (18% of PDPs), gastro-intestinal (16% of PDPs), micturition-induced (8% of PDPs), out-of-the-blue palpitations (24% of PDPs), and out-of-the-blue shortness of breath (16% of PDPs). Five mechanisms are adduced to account for this high PD prevalence as well as the specific profile of subtypes: 1) a trauma-caused panic attack diathesis; 2) trauma-event cues; 3) ethnic differences in physiology; 4) catastrophic cognitions generated by cultural syndromes; and 5) a modification of Clark's spiral of panic.

Ambulatory Care↗
PubMedDate not supplied

The pathogenesis of beta(2)-microglobulin-induced bone lesions in dialysis-related amyloidosis.

Dialysis-related amyloidosis (DRA), also referred to as beta(2)-microglobulin amyloidosis (A beta(2)M), is an important cause of morbidity in patients with chronic renal failure and in those who are on dialysis. Although DRA deposits from affected joints have been characterized as a unique amyloid fibril protein, beta(2)M, less is known about the pathologic role of beta(2)M as a mediator of bone and joint disease. Potential mechanisms for beta(2)M pathologic interaction in bone include bone growth factors, cytokines, and advanced glycation end products (AGEs). It appears that DRA is the result of a complex interaction between bone resorption and surrounding tissue destruction culminating in beta(2)M deposition and amyloid formation. More work is required to elucidate the relationship between beta(2)M accumulation and progressive tissue destruction.

Amyloidosis↗
PubMedDate not supplied

Successful treatment of mother and baby with metastatic choriocarcinoma.

The second case of successful management of a mother and neonate with metastatic choriocarcinoma is described. A response to paclitaxel in the face of platinum-refractor disease in the mother is also detailed. In a woman with a history of gestational trophoblastic disease, a high index of suspicion and thereby early diagnosis lead to prompt treatment in both mother and neonate.

Adult↗
PubMedDate not supplied

[Salt-free diet and diuretics in the elderly (author's transl)].

A salt-free diet is usually useless or dangerous in the elderly subject. It has at present only rare indications, such as after acute pulmonary oedema or congestive heart failure during initial treatment. In all other cases, it may be replaced by a reasonable diet; sodium intake remains permitted, but naturally one should not fall in the opposite extreme. As in younger subjects, and provided one takes into consideration the subjacent renal condition, properly prescribed diuretics have transformed the situation in the treatment of heart failure as in essential hypertension. Naturally the patient still requires regular clinical supervision and laboratory tests which may in practice be limited to periodical estimation of blood urea and serum potassium, less regularly, blood sugar and uric acid.

Aged↗