Regression of atherosclerotic renal artery stenosis with aggressive lipid lowering therapy.
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Adult↗
Biomedical subjects
T K Khong
Publications and source records attributed to T K Khong.
Platelet sodium-hydrogen exchanger activity and left ventricular mass.
INTRODUCTION: The sodium-hydrogen exchanger (NHE) is integral to the processes that facilitate cell growth and may contribute to the development of left ventricular hypertrophy. The aim of this study was to examine the relationship between platelet sodium-hydrogen exchanger activity and left ventricular mass index (LVMI). METHODS: Twenty male untreated Caucasians (mean age +/- s.d.: 48 +/- 13; body mass index: 29 +/- 4 kg/m(2)) with a wide range of blood pressures were studied (mean BP: 152 +/- 22/93 +/- 15 mm Hg; range: 115-190/61-117 mm Hg). Sodium-hydrogen exchanger activity was determined as the rate of sodium-dependent recovery of intracellular pH in isolated platelets loaded with BCECF and acidified to pH 6.25 using nigericin. LVMI was calculated from measurements made by M-mode echocardiography. Associations between continuous variables were examined using parametric tests. RESULTS: The mean rate of pHi recovery was 0.15 +/- 0.03 dpHi/s (range: 0.09-0.21). Mean LVMI was 120 +/- 32 g/m(2) (range: 56-178) and was not significantly correlated with either systolic (r = 0.39, P = 0.09) or diastolic blood pressure (r = 0.27, P = 0.3). Platelet NHE activity was not significantly correlated with LVMI (r = 0.06; P = 0.8). Platelet NHE activity was not significantly different between subjects with (n = 7 with LVMI >131 g/m(2)) and without left ventricular hypertrophy (n = 13). CONCLUSIONS: The results of this study show that platelet NHE activity is not significantly correlated with LVMI. These data contrast with previously described correlations of LVMI with exchanger activity measured in leucocytes and erythrocytes; and indicate that the relationship between LVMI and exchanger activity may be specific to the cell type in which exchanger activity is measured.
Adult↗
In-vivo intracellular pH at rest and during exercise in patients with essential hypertension.
BACKGROUND: Several studies in isolated cells have reported that intracellular pH (pHi) in individuals with essential hypertension may be relatively alkaline compared to normotensive individuals. Such an abnormality of pHi in hypertension would be consistent with enhanced sodium-hydrogen exchanger activity and may provide potential mechanisms by which hypertension and its complications could develop. OBJECTIVES: To determine in-vivo intracellular pH of skeletal muscle at rest and during recovery from exercise-induced acidosis in hypertensive and normotensive subjects. METHODS: Using 31-phosphorus magnetic resonance spectroscopy, pHi of the dominant flexor digitorum superficialis was measured in 20 Caucasian subjects (14 male) with essential hypertension and 20 normotensive controls matched for gender, age, race and body mass index. Measurements were made at rest and during the exercise and recovery periods of a stepped incremental maximal exercise protocol. The rate of pHi recovery from exercise-induced acidosis was calculated by linear regression over the first 210 s of recovery from the pHi time plots of respective subjects. RESULTS: Mean resting pHi in the hypertensive (7.05 +/- 0.04) and normotensive groups (7.06 +/- 0.04) were not significantly different. There was a significant effect of gender on pHi: mean pHi was 7.07 +/- 0.03 in males and 7.02 +/- 0.03 in females, respectively (P < 0.0005). The mean intracellular pH achieved by exercise was 6.74 +/- 0.31 in hypertensive individuals and not significantly different in normotensive individuals (6.68 +/- 0.19; P = 0.4). The mean rate of pHi recovery in the hypertensives was 0.08 +/- 0.03 pH units/min and not significantly different in normotensives (0.08 +/- 0.02; P = 0.4). CONCLUSIONS: These results contrast with previously documented abnormalities in the control of pHi in hypertension and demonstrate the absence of major in-vivo disturbances of pHi in skeletal muscle, both at rest and during recovery from exercise-induced acidosis, in essential hypertension. Therefore, it is possible that previously documented abnormalities of pHi and activity of the exchanger may be either specific to cell type or not present under in-vivo conditions.
Exercise↗
Platelet sodium/hydrogen exchanger activity in normotensives and hypertensives.
Increased activity of sodium/hydrogen exchange provides a potentially important mechanism for the development of hypertension. The aims of this study were to compare platelet sodium/hydrogen exchanger activity and renal acid-base excretion in normotensives and hypertensives of Caucasian origin. Platelet intracellular pH (pHi) was measured using the fluorescent dye BCECF to monitor intracellular pH. Sodium/hydrogen exchanger activity was estimated from the recovery of pHi clamped to 6.25 with nigericin. Normotensives had supine blood pressures of < 140 and < 90 mmHg; those with essential hypertension had blood pressures > 150/95 mmHg with no known secondary cause. Measurements of platelet pHi and sodium/hydrogen exchanger activity were made on 26 normotensives (ten female, sixteen male) and 25 hypertensives (five female, twenty male). All subjects were on their usual dietary sodium intake. Statistical analysis was by two-way analysis of variance for gender and blood pressure status. Group values are expressed as means+/-SD and a P value of < 0.05 was taken as being statistically significant. There were no significant differences in platelet pHi between the normotensive (n = 26) and the hypertensive (n = 25) group: pHi 7.21+/-0.14 and 7.18+/-0.16, respectively. The pHi recovery after acidification was sodium-dependent and inhibited by N-hexamethylene amiloride. Comparison of kinetic constants showed no significant differences between the normotensive and the hypertensive groups: values for rate constants and initial velocities were 0.24+/-0.04 s(-1), 0.16+/-0.03 dpHi/s for the normotensives and 0.25+/-0.05 s(-1), 0.16+/-0.03 dpHi/s for the hypertensives, respectively; there were also no significant differences in proton fluxes. The inability to find raised platelet sodium/hydrogen exchanger in the hypertensives contrasts with previous observations using other methods for the measurement of this exchanger in platelets and this raises important methodological issues in the assessment of platelet sodium/hydrogen exchanger activity.
Adult↗
The use of HMG Co-A reductase inhibitors following acute myocardial infarction in hospital practice.
Treatment with a HMG-CoA reductase inhibitor (statin) following a myocardial infarction has been shown to reduce the incidence of subsequent coronary revascularisation, myocardial infarction and cardiovascular death. The majority (89%) of patients admitted to the coronary care unit of our hospital received a fasting cholesterol check as part of a routine coronary care unit protocol. However, our survey shows that only 26% of patients surviving an acute myocardial infarction were on treatment with a statin at follow-up. Furthermore, those receiving statins were given smaller doses than those used in clinical trials. One way to ensure patients receive adequate treatment with statins, may be to include it as part of a coronary care unit protocol.
Aged↗
Delayed postpartum hemorrhage: a morphologic study of causes and their relation to other pregnancy disorders.
OBJECTIVES: To ascertain the various causes of delayed postpartum hemorrhage and to test whether subinvolution of the placental bed is associated with other pregnancy disorders for which defective maternal-fetal interaction has been implicated pathogenetically. METHODS: In a group of women presenting with postpartum hemorrhage following singleton pregnancies, tissue that had been submitted for histopathologic examination was reviewed morphologically to delineate the various causes of delayed postpartum hemorrhage. The stratified groups were analyzed for relationship to preeclampsia, fetal growth retardation (FGR), spontaneous abortion, placenta accreta, and retained placental fragments in previous pregnancies. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated for each association. RESULTS: One hundred sixty-nine cases were identified. Tissue obtained at curettage or, rarely, at hysterectomy could be categorized into seven pathologic groups: involution of the placental bed, subinvolution of the placental bed, retained placental fragments, endometritis, normal endometrium, normal decidua, or nondiagnostic tissue. Hyalinized fragments of uteroplacental (spiral) arteries that were either collapsed or completely thrombosed were seen in involution of the placental bed. Subinvolution of the placental bed was characterized by widely distended and patent residua of uteroplacental arteries with only partial occlusion by thrombosis. Women with retained placental fragments (OR 3.93, 95% CI 1.51-10.47), but not women with an involuted placental bed (OR 2.40, 95% CI 0.68-8.54) or subinvolution of the placental bed (OR 1.52, 95% CI 0.51-4.57), had increased incidences of preeclampsia, FGR, spontaneous abortion, or retained placenta in previous pregnancies when compared to women with endometritis, endometrium only, decidua only, or nondiagnostic tissue. CONCLUSION: Retained placental fragments, reflecting placenta accreta, and subinvolution of the placental bed are important causes of delayed postpartum hemorrhage. The former is associated with an increased incidence, in prior pregnancies, of pregnancy complications that probably reflect aberrant maternal-trophoblastic interaction.
Arteries↗
Dietary sodium loading increases plasma brain natriuretic peptide levels in man.
The effect of dietary sodium loading on plasma human brain natriuretic peptide-like immunoreactivity (hBNP-li) was examined in 11 normotensive subjects aged 20-23 years. Plasma hBNP-li increased significantly with increasing dietary sodium intake, with levels of 1.33 +/- 0.17 pmol/l on day 5 of a normal-sodium diet (24-h urinary sodium excretion of 171 +/- 16 mmol) and 2.04 +/- 0.10 pmol/l (P less than 0.05, versus normal-sodium diet) on day 5 of a high-sodium diet (24-h urinary sodium excretion 503 +/- 36 mmol). Corresponding plasma atrial natriuretic factor levels were 5.6 +/- 1.7 pmol/l and 11.0 +/- 2.0 pmol/l (P less than 0.05, versus normal-sodium diet) on the normal- and high-sodium diets, respectively. These results suggest that, in addition to atrial natriuretic factor, BNP may be a new and important natriuretic peptide which regulates sodium homeostasis in man during increased sodium intake.
Adult↗
The efficacy and tolerability of enteric and non-enteric coated naproxen tablets: a double-blind study in patients with osteoarthritis.
A double-blind, crossover study was undertaken to compare the efficacy and tolerability of a novel enteric coated 500 mg naproxen tablet with normal release 500 mg naproxen in patients with osteoarthritis. Eighty-eight patients were randomly allocated to receive enteric coated naproxen as a single daily dose of 2 tablets at night or 1 normal release naproxen tablet twice daily for a period of 3 weeks, followed by the alternative treatment for a further period of 3 weeks. The results of patient and doctor assessments showed that both treatments were increasingly efficacious, with a significant period effect found in the measures for pain on passive movement and duration of morning stiffness. No significant treatment differences were seen in any of the measures of efficacy and tolerability, although there were more withdrawals on normal release than on enteric coated naproxen (p = 0.07). It was concluded that enteric coated naproxen given as a single 1 g dose at night and normal release 500 mg naproxen given twice daily are equally efficacious and well tolerated.
Adult↗
Controlled-release indomethacin and sustained-release diclofenac sodium in the treatment of osteoarthritis: a comparative controlled clinical trial in general practice.
A double-blind, crossover study was undertaken in general practice to compare the efficacy and tolerability of a new controlled-release indomethacin with sustained-release diclofenac sodium in patients with osteoarthritis. Eighty-four patients were randomly allocated to receive controlled-release indomethacin tablets (75 mg) or sustained-release diclofenac sodium tablets (100 mg) at night for a period of 4 weeks before being crossed-over to receive the alternative treatment for a further 4 weeks. Pain scores for day and night, duration of morning stiffness, requirement for escape analgesia, and treatment preference were similar for both treatments. There was no significant difference between treatments for incidence and severity of side-effects. It was concluded that controlled-release indomethacin tablets (75 mg) given as a single night-time dose were as efficacious and well tolerated as sustained-release diclofenac sodium (100 mg).
Adult↗
Depression in general practice: a comparison of flupenthixol dihydrochloride and dothiepin hydrochloride.
A single-blind, parallel group, general practice study was carried out in 153 patients with mild to moderate depression to compare the efficacy and tolerability of flupenthixol dihydrochloride and dothiepin hydrochloride. Patients were allocated at random to receive single daily doses of either 1 mg flupenthixol in the morning or 75 mg dothiepin in the evening, and this dose could be doubled at the end of 2 weeks in the event of inadequate response. Assessments were made on entry and after 1, 2, 4 and 6 weeks of treatment using the Hamilton Depression Rating Scale, a 4-point severity scale and an unwanted symptoms checklist. The results showed that both treatments significantly improved the patients' condition over 6 weeks, and there was a significant difference in favour of flupenthixol at end-point. Both drugs were well tolerated, although persistence of anticholinergic side-effects in the dothiepin group resulted in a trend favouring flupenthixol. One patient in the flupenthixol group attempted suicide by overdose but made a complete recovery.
Adolescent↗
Flurbiprofen-aspirin interaction: a double-blind crossover study.
Fifteen patients with seropositive rheumatoid arthritis were treated for 2-weeks periods with 150 mg flurbiprofen daily and with flubriprofen in the same dosage plus 3 g aspirin daily, the treatments being administered in random allocation. The results showed that there were no significant differences clinically between the two treatments. Serum levels of flurbiprofen were measured during both treatment periods in 4 patients. During the flurbiprofen and aspirin period there was a full in the serum levels of flurbiprofen was unchanged. No obvious reduction in clinical efficacy was apparent.
Arthritis, Rheumatoid↗
Arthritis associated with cimetidine.
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Adult↗
Manubriosternal joint subluxation in rheumatoid arthritis.
Manubriosternal joint involvement in rheumatoid arthritis is not rare and may be evidenced by erosion, reactive sclerosis and ankylosis. Frequent reports of such involvements appear in the radiological literature but only 3 cases where this had been associated with clinically evident subluxation of the joint have been reported previously. It is, nonetheless, our observation that clinical deformity of this joint is common and careful review at our clinic has revealed the 10 cases reported here. Chronic or recurrent chest infections have been incriminated in the production of this deformity. However, the evidence seen in our series suggests rather, that this deformity is closely associated with severe cervicodorsal spinal erosion and deformity and that its presence should alert clinicians to potential problems of cervical cord compression.
Aged↗