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Biomedical subjects

M Tong

Publications and source records attributed to M Tong.

At least 37 records · Page 2Linked to original sources
PubMed1999

[A modified MacConkey medium].

We used MacConkey Agar(MCA) medium powder as a basis and added 6-benzoy-2-naphthyl phosphate disodium salt to modify MCA medium. This method was identified by examining several kinds of enteric pathogenic bacteria. Thus it allows us to observe lactose fermentative and phosphatase reaction simultaneously and to recognize Enterobacteriaceae from non-fermentable bacteria on primary culture plates according to the color of colony. This improved method simplifies the recognition procedure and shortens the time so that it is helpful to correctly choosing identification kit.

Culture Media↗
PubMed1999

Magnetic resonance imaging of the eustachian tube in nasopharyngeal carcinoma: correlation of patterns of spread with middle ear effusion.

OBJECTIVE: The purpose of this study was to use multiplanar high-resolution magnetic resonance imaging (MRI) to detail the patterns of tumor spread in nasopharyngeal carcinoma (NPC) and to correlate the findings with the presence of an effusion in the middle ear and mastoid. MATERIALS AND METHODS: Magnetic resonance imaging was performed in 51 patients with newly diagnosed NPC, providing 102 individual sides for analysis. RESULTS: Fifty-nine lateral walls of the nasopharynx were involved by NPC. Tumor involved the lateral recess (55), eustachian tube orifice (41), levator palatini (LP) (32), torus tubarius (TT) (21), pharyngobasilar fascia (38), tensor palatini (TP) (17), parapharyngeal fat space (PFS) (19), main body of the cartilaginous eustachian tube (CET) ( 13), bony eustachian tube (0). middle ear (0), and inner ear (0). Effusions were present in 32 (54%) of the 59 involved sides. Effusions were found to be associated with the following patterns of spread: tumor causing major displacement of the CET without invasion (3 of 4), tumor invading TT or LP with minor displacement of the TT (4 of 7) or major displacement of the CET (7 of 7) and advanced invasion involving the TP, PFS, or CET with major displacement of CET (18 of 19). Effusions were not seen in tumors without invasion that were restricted to the lateral recess or eustachian tube orifice either with no displacement (O of I I) or with minor displacement (O of 1 1) of the TT. Effusions were present in 28 of 30 cases with major displacement of the main body of the CET, 4 of 18 with minor displacement of the TT, and 0 of 11 with no displacement. Displacement of the eustachian tube was a significant factor in the production of an effusion (p < 0.00001) and remained significant even after exclusion of all cases of advanced invasion (p < 0.0001). CONCLUSION: The cause of an effusion in NPC is multifactorial. Magnetic resonance imaging has shown invasion of the tensor palatini muscle in patients with an effusion, suggesting a functional cause. However, displacement of the eustachian tube is a significant factor in patients with middle ear and mastoid effusions.

Adult↗
PubMed1998

Relationship between biochemical and virological responses to interferon therapy in chronic hepatitis C infection. Consensus Interferon Study Group.

We have investigated the relationship between serum alanine aminotransferase (ALT) and hepatitis C virus (HCV) RNA in the assessment of responses to interferon (IFN) therapy in chronic HCV infection. Data from 704 patients with HCV infection who were randomized to receive consensus IFN-alpha (CIFN) 3 micrograms (n = 232 patients) or 9 micrograms (n = 232 patients), or IFN-alpha 2b 3 million units (MU) (n = 240 patients), were used for these analyses. All patients were treated three times weekly. Hepatitis C viral RNA (HCV RNA) was determined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) with a lower limit of detection of 100 copies ml-1. Of patients with normal serum ALT concentrations, 53% (120/225) had undetectable HCV RNA at the end-of-treatment period and 47% (51/109) had undetectable HCV RNA at the end of the post-treatment observation period. In contrast, of the patients with undetectable HCV RNA, 75% (120/161) and 84% (51/61) had normal serum ALT activities at the end-of-treatment and post-treatment observations periods, respectively. The majority of patients with undetectable HCV RNA had normal ALT values. In contrast, only half of the patients with normal ALT values were negative for HCV. End-of-treatment HCV RNA response also better predicted sustained virological response than did end-of-treatment ALT response.

Adult↗
PubMed1998

A prospective study of the risk of transfusion-acquired viral infections.

The risk of transfusion-transmitted viral infections may be estimated by several methods, but only prospective studies of transfusion recipients can directly measure the incidence, with associated 95% upper confidence bound, of these infections. From 1989 through 1995, 764 recipients of allogeneic or autologous red blood cell transfusions were enrolled; 486 (64%) provided both pretransfusion and 6-month follow-up specimens. Both specimens were tested for anti-HBc, anti-HCV, anti-HTLV-I and anti-HIV, with appropriate confirmatory testing. Thirty-nine (8.0%) subjects had seroprevalent anti-HBc, 19 (3.9%) subjects had seroprevalent anti-HCV, three (0.6%) subjects had seroprevalent anti-HTLV-I/II, and one (0.2%) subject had seroprevalent anti-HIV. There were no seroconversions for any agent among the 34 patients who received only autologous blood, and no confirmed seroconversions for anti-HTLV-I or anti-HIV among all subjects. There were three seroconversions for anti-HBc (incidence 1.04 x 10(-3); 95% confidence interval (CI) 2.15 x 10(-4), 3.05 x 10(-3) per allogeneic unit transfused), and two confirmed seroconversions for HCV (incidence 6.94 x 10(-4); 95% CI 8.34 x 10(-5), 2.51 x 10(-3) per allogeneic unit transfused). One of the two anti-HCV seroconversions occurred in March 1994, after the institution of HCV EIA 2.0 screening of donated blood. Transfusion-associated seroconversions to hepatitis B and C markers were observed at low rates in the early 1990s despite testing donors for markers of both viruses, whereas seroconversions to HTLV-I or HIV were less than 1.04 x 10(3) per allogeneic unit transfused, based upon the upper 95% confidence interval of the zero incidence in this study.

Adult↗
PubMed1996

Effects of steroid on diaphragmatic functions in rabbits.

The effects of steroid on diaphragmatic contractility and endurance were examined in 24 New Zealand rabbits. Diaphragmatic contractility was determined by measuring gastric pressure (Pga) with the lower thorax and the abdomen of the animal being fixed with a rigid cast. Endurance procedure was done by continuous 15 Hz stimulation of the bilateral phrenic nerves, and diaphragmatic endurance was expressed as the time from the initiation of the endurance procedure to the moment when transdiaphragmatic pressure 15 Hz (Pdi-15 Hz) decreased to 25% of Pdimax-15 Hz. Our data suggested that intravenous administration of dexamethasone 2.5 mg daily for 7 days did not affect the diaphragmatic contractility significantly, but could cause a significant decrease in diaphragmatic endurance. When delivered intravenously at the dose of 2.0 mg daily for 14 days, dexamethasone induced a significant decrease both in diaphragmatic contractility and endurance. The recovery of the diaphragmatic strength from fatigue, however, was not influenced by dexamethasone in either circumstance. The influence of dexamethasone on diaphragmatic contractility and endurance may have important clinical implications.

Animals↗
PubMed1995

Rothmund-Thomson syndrome in fraternal twins.

Fraternal twins of Malay descent had the Rothmund-Thomson syndrome. This is a rare, autosomal recessive disorder characterized by photosensitivity, poikiloderma, short stature, skeletal defects, and juvenile cataracts. This is the first case report of the syndrome from southeast Asia.

Adolescent↗
PubMed1995

A review of dermatomyositis cases at Hospital Besar Kuala Lumpur 1989-1993.

Eight cases of dermatomyositis were seen in the Skin Department, Hospital Besar Kuala Lumpur between 1989 and 1993. There was one case of juvenile dermatomyositis. There was a majority of Chinese patients (87.5%). There were three patients (37.5%) with underlying malignancies, two of which (66.7%) were nasopharyngeal carcinomas; all were under the age of fifty years. It is important to screen all adult patients for underlying malignancies, even those in the younger age group.

Adult↗
PubMed1994

Comparative studies of the core gene products of two different hepatitis C virus isolates: two alternative forms determined by a single amino acid substitution.

We have compared the expression of the core gene of two different hepatitis C virus (HCV) isolates, HCV-1 and HCV-RH, using the in vitro translation assay. In the absence of the downstream E1 envelope protein sequence, a 16-kDa protein (P16) was the dominant protein product synthesized from the HCV-1 core gene sequence. On the other hand, a 21-kDa protein (P21) was the dominant protein product synthesized from the HCV-RH sequence. Domain-swapping and site-directed mutagenesis experiments indicated that codon 9 of the core protein coding sequence played a crucial role on the synthesis of the core protein: a lysine codon at this position led to the synthesis of P16 and an arginine codon at this position led to the synthesis of P21. For HCV-1 and HCV-RH, this codon encodes lysine and arginine, respectively. Further analyses indicated that P16 was likely co-amino-terminal with P21. In the presence of the downstream E1 envelope protein sequence and microsomal membranes, P16 as well as P21 were synthesized from the HCV-1 core gene sequence whereas P21 remained the only detectable protein product synthesized from the HCV-RH core gene sequence. These results indicate that the pathway leading to the synthesis of the HCV core protein may be more complicated than originally envisioned.

Amino Acid Sequence↗
PubMed1994

Combined therapy of captopril and spironolactone for refractory congestive heart failure.

It is traditionally considered that angiotensin--converting enzyme inhibitor (ACEI) and spironolactone could not be used simultaneously because of the assumed risk of hyperkalemia. However, despite ACEI therapy edema and congestive status remain in some of the patients with severe congestive heart failure (CHF). In order to seek an effective therapy for these patients, we observed the efficacy and safety of captopil plus spironolactone in patients with refractory CHF, with strict monitoring of renal function, serum and urine electrolytes and blood pressure (BP). Thirty-five patients with refractory CHF and New York Heart Association functional class IV without renal dysfunction, hypotension and hyperkalemia, whose plasma aldosterone (ALD) level in 88.6% of them was above normal value, were randomly assigned to group A (n = 16, captopril alone) and B (n = 19, captopril plus spironolactone) for a 4-week treatment. The dosage of both drugs was individually adjusted in time according to the results of serum potassium and renal function. The improvement in dyspnea--fatigue ratings, urinary volume and Na+/K+ ratio in group B was more significant than that in group A, and the plasma ALD level in group B decreased obviously while it remained high in group A after therapy. Two patients in group B who had had normal plasma ALD level with urinary Na+/K+ ratio > 1.0 before the therapy did not exhibit any clinical improvement. A strong negative correlation was found between plasma ALD level and urinary Na+/K+ ratio (correlation coefficient -0.689, P < 0.01). None of the patients had obvious hyperkalemia and hypoaldosteronism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[A study of captopril enhancement of nitrate effect coronary arterial disease patients associated with heart failure].

It is shown in a prospective study that the initial beneficial hemodynamic effect of nitroglycerine (NTG) significantly decreased after continuous 3-day infusion of this drug (10-50 micrograms/min) in acute myocardial infarction (AMI) patients associated with acute left heart failure. The effect of ameliorating anginapectoris and improving heart function with isosorbide dinitrate (ISDN) gradually decreased almost to pretreatment levels after oral administration of this drug (10-20mg, 4 times daily) for 3 weeks in anginapectoris patients associated with congestive heart failure (CHF) with accompanying increased level of plasma angiotensin II (AII) and body weight. However, when captopril (CPT, 12.5-25mg, 3 times daily) was combined with nitrates, the clinical effects were enhanced and maintained throughout the study, along with a decrease in the level of AII and body weight. In the hearts of rats perfused with CPT and NTG, the coronary flow (CF) significantly increased as compared with the flow when either drug was used alone. Enelapril (ENL, a non-sulfhydryl drug), however, did not show such effect. The above results indicate that repletion of sulfhydryl to vascular smooth muscle and antineurohumoral activation may be the potential mechanisms by which CPT reverses nitrate tolerance and enhances its clinical effects.

Adult↗
PubMed1993

Confocal imaging of the alpha 6 and beta 4 integrin subunits in the human cornea with aging.

PURPOSE: The purpose of this study was to examine changes in the distribution of integrin subunits, alpha 6 and alpha 4, in the normal human cornea with age. METHODS: Thirty normal corneas were examined and divided into three groups; corneas from children younger than 2 years, corneas from adults 29 to 70 years, and corneas from adults older than 70 years. The corneas were frozen and the sections were cut, double-stained with monoclonal antibodies to the integrin subunits, and visualized with Texas Red or fluorescein using confocal laser scanning microscopy. Computer imaging was conducted to determine differences. RESULTS: The alpha 6 subunit was generally localized along the basal and lateral surfaces of basal epithelial cells and projected into Bowman's membrane. The beta 4 subunit was only present along the basal surface. Overall, the major age-related difference was the loss of continuous alpha 6 and beta 4 subunits along the basal surface of basal epithelial cells. When reconstructed images from corneas of individuals older than 70 years were optically sectioned en face, the alpha 6 subunit appeared discontinuous. If the same optical images were viewed from corneas of younger individuals, the staining was continuous. The number and distribution of hemidesmosomes along the basal lamina did not change with age in the corneas examined. CONCLUSIONS: Using computer imaging associated with confocal laser scanning microscopy, we have demonstrated that there is an age-related change in the localization of the alpha 6 and beta 4 subunits.

Adult↗
PubMed1992

[Effect of captopril on the exercise performance in patients with congestive heart failure].

We studied the effect of captopril on exercise performance in 30 patients with congestive heart failure using a randomized, double-blind and placebo-controlled method. 4-week captopril treatment can significantly increase the exercise tolerance time and work load, heart function, blood flow in exercising lower limbs as well as oxygen metabolic capacity. However, 3-day captopril treatment had no effect on exercise performance. A significant correlation was found between improvement in exercise performance and the pretreatment level of plasma angiotensin II. The increased levels of plasma prostaglandins E 2 and I 2 after captopril treatment were also correlated with improvement of exercise performance. The results indicated that long-term captopril treatment can increase exercise performance in congestive heart failure by improving both central and peripheral hemodynamics and metabolism. Certain vasomotor or endocrine factor may play a mediate role in the above changes.

Adult↗