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Biomedical subjects

S S Ho

Publications and source records attributed to S S Ho.

50 records · Page 3Linked to original sources
PubMed1992

Acute renal failure in hepatitis B virus-related membranous nephropathy with mesangiocapillary transition and crescentic transformation.

We report the first case of hepatitis B virus (HBV)-related membranous nephropathy (MN) that progressed to crescentic transformation superimposed on a mixed membranous and mesangiocapillary glomerulonephritis. The patient developed acute renal failure, which partially responded to pulse methylprednisolone therapy, and subsequently recovered after plasma exchange.

Acute Kidney Injury↗
PubMed1990

Hepatocellular carcinoma with cardiac cirrhosis.

Hepatocellular carcinoma is a recognized complication of hepatic cirrhosis, most commonly associated with alcohol excess, haemochromatosis and chronic hepatitis B infection. Long-standing hepatic venous congestion may cause cirrhosis. A search of the literature has not revealed a case of hepatocellular carcinoma complicating cardiac cirrhosis. A case is described and the association is discussed.

Carcinoma, Hepatocellular↗
PubMed1985

Dietary beliefs in health and illness among a Hong Kong community.

Dietary adjustment for health promotion and maintenance and for helping the body to expedite its recovery from illness conditions has been part and parcel of the Chinese medical culture. The paper reports on the extent traditional dietary beliefs in health and illness persist in a fast changing Hong Kong community. It explores the community interpretation of the role of diet therapy; and the relationship of social demographic variables with peoples' tendency to give traditional dietary suggestions. Traditional beliefs were found to be quite prevalent. Differentiation in responses was seen for different types of belief concepts. Over 80% of respondents had strong belief in the role of diet expediting recovery during illnesses. Measles and anaemia were used as indicators to look at the types of foods suggested for consumption or avoidance and the rationale behind the suggestions. Explanations of diet therapy for measles were in general traditionally based and that for anaemia were based on a mix of traditional and modern concepts. While there is a tendency for the more Chinese culturally affiliated in this study population to have stronger traditional food beliefs, the relationship of social demographic factors with the tendency to give dietary suggestions for specific diseases are not clear. Diet therapy is a form of self-care and is an inseparable part of the total health care system in the community. The efficacy of traditional food remedies and the role of diet therapy in self-care should be further explored.

Adult↗
PubMed1985

On the mechanism of renal vasoconstriction induced by acetylcholine in indomethacin-treated dogs.

Renal arterial infusion of acetylcholine (ACh) in control dogs produced a natriuresis and diuresis and an increase in renal plasma flow (RPF) without a change in glomerular filtration rate (GFR) or in renin secretory rate (RSR). In dogs pretreated with indomethacin (Indo), an inhibitor of prostaglandin synthetase, renal arterial infusion of ACh first produced a rise, then a decline in urine flow, sodium excretion (UNaV) and GFR that was accompanied by a progressive fall in RPF and a progressive rise in RSR. The rise in RSR was potentiated by renal arterial infusion of an alpha-adrenergic receptor blocker, phenoxybenzamine (Phenoxy), and attenuated, but not completely abolished, by beta-adrenergic receptor blockade with propranolol (Prop). Chemical denervation with reserpine alone, or in combination with chronic surgical renal denervation, failed to prevent the fall in RPF, GFR and UNaV and the rise in RSR produced by ACh in Indo-treated dogs. Renal arterial infusion of Phenoxy and intravenous infusion of Prop, alone or in combination with renal arterial infusion of an angiotensin II antagonist, saralasin, failed to maintain the vasodilatory, diuretic and natriuretic effects of ACh in Indo-treated dogs. Elimination of endogenous vasopressin by hypophysectomy also failed to prevent the vasoconstriction induced by ACh in Indo-treated dogs. The results suggest that ACh produced renal vasoconstriction in Indo-treated dogs by mechanism(s) other than an increase in renal adrenergetic activity or an increase in the activity of the renin-angiotensin system. The results also suggest that the vasoconstriction was independent of vasopresin.

Acetylcholine↗
PubMed1984

Prostaglandin E2 but not F2 alpha restores the natriuretic response to acetylcholine in indomethacin-treated dogs.

Renal arterial infusion of acetylcholine (ACh) (40 micrograms/min) produces a natriuresis, diuresis, and an increase in renal plasma flow (RPF) without a change in glomerular filtration rate (GFR) or renin secretory rate (RSR). The present study was designed to examine the role of prostaglandins in this natriuretic response to ACh. In dogs pretreated with indomethacin (Indo) (5 mg/kg, i.v.), an inhibitor of prostaglandin synthesis, renal arterial infusion of ACh produced an increase and then a decline in urinary flow and sodium excretion accompanied by a progressive fall in GFR and RPF and a progressive increase in RSR. Renal arterial infusion of PGE2 (1.9 micrograms/min) but not PGF2 alpha (1.9 micrograms/min) before and during the infusion of ACh restored the diuretic and natriuretic response to ACh in Indo-treated dogs. Renal arterial infusion of bradykinin (BK) (3 micrograms/min) in Indo-treated dogs produced a diuresis and natriuresis similar to that produced by PGE2; renal arterial infusion of BK, however, did not restore the diuretic and natriuretic response to ACh in Indo-treated dogs. The data suggest that Indo shortens the diuretic and natriuretic response to ACh by inhibiting synthesis of prostaglandins, possibly PGE but not PGF. The data further suggest that PGE2 restores the diuretic and natriuretic response to ACh in Indo-treated dogs through a specific action rather than by its action as a renal vasodilator.

Acetylcholine↗
PubMedDate not supplied

Mathematical evaluation of the influence of adverse effect on therapeutic efficacy in a direct response system: a case of pharmacodynamic variability of adverse effect.

Two major concerns in therapeutics are the efficacy (E) and adverse effects (Ae) exhibited by a pharmacological agent. Although these elements are studied routinely in both animals and humans during the drug development processes, the data are usually considered independently and in different contexts. Since E and Ae are different yet inseparable components in drug therapy, E should not be used as the sole descriptor for drug responses. To accommodate the influence of Ae on E, the present approach requires the observed Ae data to be transformed to the equivalencies of E data (Ae'). Using appropriate pharmacokinetic modeling techniques, this approach permits the prediction of the adjusted therapeutic effect (ATE) (i.e. , E minus Ae') as a function of time. Effects of pharmacodynamic variability of Ae due to variations in Hill's parameters (i.e., Ae (max), AeC (50), and n (Ae) ) on ATE were studied by computer simulations for a hypothetical one-compartment model drug that displays simple first-order absorption and elimination with central sites for E and Ae. An increase in Ae' (max) and a decrease in AeC (50) and n (Ae) cause a downward shift and peak inversion on the ATE versus time curves coupling with a longer duration of influence of Ae on E. Results also showed that the downward shift of these curves was more apparent with decreasing n (Ae) values and that peak inversion became less noticeable for n (Ae) values <1.5. Subsequent analyses established the optimal dose for the hypothetical drug studied. This approach allows a more comprehensive description of the time course of the overall drug responses and is potentially useful for therapeutic drug monitoring and dose selection during the drug development process.

Algorithms↗
PubMedDate not supplied

Ca2+ antagonists and db-cAMP sustain a rise in renal blood flow induced by acetylcholine in indomethacin-treated dogs.

Renal arterial infusion of acetylcholine (ACh) in the dog normally produces a sustained rise in sodium excretion (UNaV) and in renal plasma flow (RPF). When prostaglandin (PG) synthesis is inhibited, ACh induces only a transient increase in UNaV and RPF followed by a progressive decline in UNaV and RPF, and a rise in renin secretory rate (RSR). Renal arterial infusion of PGE2 but not a vasodilator such as bradykinin restored the response to ACh to normal in indomethacin (Indo)-treated dogs. During renal arterial infusion of dibutyryl cyclic AMP (6 mg/min), ACh also produced a sustained increase in UNaV and RPF despite an inhibition of PG synthesis by Indo. Renal arterial infusion of verapamil (60 micrograms/min) or diltiazem (60 micrograms/min) also prevented the subsequent fall in RPF when ACh was infused; RSR, however, did not show a rise. The results suggest that synthesis of PGE2 with stimulation of cAMP is required for sustained ACh action. When PGE synthesis is inhibited, ACh may produce renal vasoconstriction by increasing intracellular Ca2+ concentration. The partial effect of calcium channel blockers suggests that release of calcium from intracellular stores as well as calcium entry may mediate the response.

Acetylcholine↗
PubMedDate not supplied

Comparison of oral ciprofloxacin and amoxycillin in treating infective exacerbations of bronchiectasis in Hong Kong.

A randomised double-blind controlled clinical trial was conducted to compare oral ciprofloxacin (500 mg b.d.) and amoxycillin (1 g t.d.s.) in the treatment of infective exacerbations of bronchiectasis. The commonest organism isolated from sputum was Pseudomonas aeruginosa, which accounted for 34% of all positive sputum cultures. Other Pseudomonas species and Haemophilus influenzae, accounted for 19%, respectively. Ciprofloxacin produced better clinical response, a higher sputum to serum antibiotic level (mean of 0.65 in the ciprofloxacin group vs. 0.18 in amoxycillin group, p = 0.0001), broader spectrum of antibacterial activity and less side-effect. It was also better tolerated by patients. The findings suggest that ciprofloxacin is an effective treatment of infective exacerbations of bronchiectasis.

Administration, Oral↗
PubMedDate not supplied

The effects of ice on blood flow and bone metabolism in knees.

The effects of an ice wrap, applied to a knee for 20 minutes, on blood flow and bone metabolism were measured using triple-phase technetium bone scans. Twenty-one subjects between 29 and 63 years of age were studied. A commercially available ice wrap was applied to one knee 20 minutes before scanning, while an identical wrap left at room temperature was applied to the opposite knee to act as a control. Scans of the knees were obtained at the completion of cooling, and the images were quantified by computer image analysis for each knee at each phase of the scan. Percentage of decrease in blood flow and subsequent bone uptake of technetium for the iced knee as compared with the opposite knee were calculated. All iced knees demonstrated decreased arterial and soft tissue blood flow as well as decreased bone uptake, which is a reflection of changes in both bone blood flow and metabolism. The average decrease was 38.4% +/- 4.97 in arterial blood flow, 25.8% +/- 2.04 in soft tissue blood flow, and 19.3% +/- 2.0 (standard error of the mean in each) in bone uptake. This "ice effect" was not related to age, sex, knee circumference, or skin temperature after cooling. By decreasing blood flow and cell metabolism, ice theoretically can limit hemorrhage and cell death in the setting of acute traumatic injury. This study thus provides a scientific rationale for the use of ice as tested for such injuries to a large joint, whether in the soft tissues or bones.

Adult↗
PubMedDate not supplied

Comparison of various icing times in decreasing bone metabolism and blood flow in the knee.

In a previous study we used technetium-99m bone scans to show that cooling a knee for 20 minutes with a standard ice wrap will decrease soft tissue blood flow by a mean of 26%, and skeletal blood flow and metabolism by 19%. The present study examined the effects of shorter and longer icing periods to determine minimum cooling time for a measurable and consistent decrease, and time to produce maximal decrease within a safe period of icing (< 30 minutes). Thirty-eight subjects were studied. An ice wrap was applied to one knee for an assigned time (5, 10, 15, 20, or 25 minutes). Triple-phase bone scans of knees were obtained; mean percentages of decrease in the iced knee for each of the five time groups at each of the three phases of the bone scan were calculated and compared. Mean decreases of 11.1% in soft tissue blood flow, and 5.1% in skeletal metabolism and blood flow were measured at 5 minutes; maximums of 29.5% and 20.9%, respectively, were obtained at 25 minutes. A small but consistent decrease in soft tissue blood flow and skeletal blood flow and metabolism in a knee appear to be obtained with as little as 5 minutes of ice application. This effect is time-dependent and can be enhanced three- to four-fold by increasing the ice application time to 25 minutes.

Adult↗
PubMedDate not supplied

The use of corticosteroid/beta-blocker combinations in the management of regression after PRK for high myopia.

After nearly 8 years of clinical experience, and with conflicting evidence from trials with and without corticosteroids, there is still no single, universally agreed postoperative management regimen for photorefractive keratectomy (PRK). All agree that corticosteroids will reverse sudden regressions, and so most still use varying corticosteroid regimens. In Hong Kong we are faced with many patients whose myopia is greater than -6 diopters (D), and we agree with the general observation that the regression/haze rate is much greater for these higher errors, and that increased intraocular pressure (IOP) seems to be associated with increased haze. We placed our high myopia group (greater than -6.00D) on corticosteroid/beta-blocker combinations and observed a much lower incidence of haze and regression from this group. We use this regimen now on all our patients and are achieving more accurate endpoint refraction and less haze. Our hypothesis is that lowering the IOP to less than 16 mm Hg reduces keratocyte migration by "tightening" the corneal lamellae, thus dampening the healing response. Case studies are presented to illustrate this relationship.

Administration, Topical↗
PubMedDate not supplied

Bilateral simultaneous myopic PRK as experienced by an ophthalmologist.

We have been performing excimer laser photorefractive keratectomy (PRK) and phototherapeutic keratectomy (PTK) since November 1991. As of August 1992, we had done 83 PRKs, of which 28 were bilateral, including two patients who had just 3 days separation between procedures. The majority of our patients requested PRK because of contact lens intolerance in Hong Kong's dusty environment. Some requested bilateral surgery at the same operative session to avoid anisometropia without their contact lenses, as well as to endure only one laser surgery with its attendant discomfort. As the bilateral approach became a routine part of our laser practice, many patients who had opted for unilateral procedures stated that, had they been able to take a little more time off, they also would have preferred this technique.

Adult↗