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Biomedical subjects

W Wong

Publications and source records attributed to W Wong.

At least 163 records · Page 9Linked to original sources
PubMed1989

Effect of acute experimental influenza A virus pneumonia on concentration of alpha 1-acid glycoprotein in mouse serum.

In mice, the mean serum concentration of the acute-phase reactant alpha 1-acid glycoprotein increased 34-48% over 14 days following experimental induction of pneumonitis by intranasal inoculation of influenza A virus. Inoculation of undiluted (hemagglutination titer 640) and 10(-1) dilution of virus was followed by development of maximum concentrations of alpha 1-acid glycoprotein in serum at seven days, of 334 micrograms/ml, compared to a concentration in control mice inoculated with irradiated inactivated virus of 225 micrograms/ml (P = 0.002). Infection with 10(-2) virus yielded a peak serum alpha 1-acid glycoprotein of 301 micrograms/ml at four days, 34% higher than in control mice at four days (P = 0.04). There were no differences in alpha 1-acid glycoprotein concentrations among virus-infected mice. Influenza A virus pneumonitis was confirmed histologically, by virus isolation, and by serologic testing, but no inoculum-dependent differences were observed. On day 7, there was a direct relationship demonstrated between the severity of pneumonitis evaluated histologically and the serum alpha 1-acid glycoprotein concentration (r = 0.50; P less than 0.02). Influenza A pneumonia in mice is associated with increased concentrations of alpha 1-acid glycoprotein in serum; the increase may be directly related to the severity of the pulmonary inflammation.

Acute Disease↗
PubMed1989

PORCH test.

Explore the source record for details and available documents.

Collateral Circulation↗
PubMed1989

Late metabolic acidosis and poor weight gain in moderately pre-term babies fed with a casein-predominant formula: a continuing need for caution.

When our neonatal unit opened in 1984 our formula feeding policy for moderately preterm babies was for casein-predominant rather than "humanized" whey-predominant milk formulae to be given. However, an early cluster of cases of late persistent metabolic acidosis prompted an investigation into the acid-base status and weight gain in preterm infants. This study of 70 healthy, moderately preterm (32-35 weeks) Chinese babies has convincingly shown that a casein-predominant low protein formula is associated with significant metabolic acidosis, persisting sometimes for as long as 8 weeks, and poor weight gain when compared with infants fed on either a humanized or a special low-birthweight formula. This is an important message for the many neonatal units in developing countries where the cost of humanized formulae might initially seem prohibitive, encouraging instead casein-predominant formulae when breast milk is not available. Any additional expense incurred in using humanized formulae will be compensated for by the shortened time spent in hospital.

Acidosis↗
PubMed1989

Elderly people taking non-steroidal anti-inflammatory drugs are unlikely to have excess renal impairment.

The importance of possible adverse effects on renal function of non-steroidal anti-inflammatory drugs has been widely discussed. Elderly people have been thought to be particularly at risk. We therefore studied simple indices of renal function and plasma potassium in 54 patients with a mean age of 85 years, 27 taking these drugs and 27 controls. Twenty five of our 54 patients were also taking diuretics. Non-steroidal anti-inflammatory drugs did not affect renal function or plasma potassium in these patients.

Aged↗
PubMed1988

Purification and characterization of an endonuclease from fruiting caps of basidiomycete Coprinus cinereus.

An endonuclease was purified from the cap tissues of basidiocarp of Coprinus cinereus collected at early meiotic prophase. It has an optimal activity at pH 7.0 and 37 degrees C. It is a cationic enzyme with a molecular mass of 22 kDa by gel filtration, and contains a 12-kDa and a 14-kDa peptide as revealed by SDS gel electrophoresis and Western blot analysis. An antiserum was produced in rabbits against the purified Coprinus endonuclease. The specificity of this antiserum was demonstrated in a dot-blot analysis and, more critically, in an immunoinhibition of endonuclease activity. The Coprinus endonuclease requires Mg2+ and/or Ca2+ as co-factors. Ca2+ is more efficient than Mg2+ while the effect of combining both co-factors is the highest. The Coprinus endonuclease has a substrate preference for single-strand and supercoiled DNA. It gives only single-strand nicks on supercoiled DNA at low enzyme concentration and limited time of incubation. At high enzyme concentration and/or long incubation time, double-strand fragmentation occurred. As is discussed, this endonuclease is believed to be involved in the early phase of meiotic recombination.

Agaricales↗
PubMed1988

Analysis of hemin-induced protection of human hemopoietic cells from the cytotoxic effects of anthracyclines.

Experiments were performed with K562 erythroleukemia cells to further characterize the observation that hemin protects hemopoietic cells from the cytotoxic effects of anthracycline drugs. The present studies demonstrate that this protective effect of hemin applies only to anthracyclines and not to other classes of antineoplastic agents. Hemin interferes with the cellular accumulation of various anthracyclines, as measured by cytofluorography, and prevents binding of anthracyclines to isolated cell nuclei. Exposure of K562 cells to hemin retards the anthracycline-induced arrest of cells at the G2-M interphase of the cell cycle and permits cells to undergo continuing division as demonstrated by clonal growth in plasma clot cultures. Furthermore, hemin decreases the ability of anthracyclines to unwind simian virus 40 supercoiled DNA in vitro. The protective effect of hemin fails to occur if cells have been preincubated with this agent for 72 h before they are exposed to Adriamycin in the absence of hemin. The findings suggest that hemin prevents anthracycline-induced cytotoxicity by acting at several levels. These effects may be mediated by direct interactions of hemin with DNA and perhaps other cellular constituents or by molecular complex formation between hemin and anthracyclines at intracellular sites.

Antibiotics, Antineoplastic↗
PubMed1988

Hazards of angioscopic examination: documentation of damage to the arterial intima.

The fiberoptic scope is increasingly used in the coronary and peripheral arteries to quantitate the degree and type of arterial obstructive disease and to inspect the results of procedures such as bypass grafting and laser irradiation of obstructive lesions. Since little is known about this instrument's potential complications, we passed a variety of fiberoptic scopes (1.8 to 3.6 mm outer diameter) in fresh postmortem pig coronary arteries and live monkey and canine peripheral arteries, and observed the intraluminal anatomy through the angioscope. No perforations were created, but ridges rising from the vascular luminal surface, avulsion of the endothelial lining, and small flaps attached at one end to the vessel wall were observed. Histologically, subintimal and medial tears were evident. Inserting large diameter scopes or making frequent passes (10 to 100) in coronary arteries increased intravascular injury. The use of small diameter flexible scopes or infrequent passes (less than 10) in the larger iliac and femoral arteries of live monkeys and dogs resulted in a lower frequency of myointimal sloughing or flap formation. Current fiberoptic scopes are not ideal angioscopes; they have a rigid tip, cannot be steered adequately, and are relatively stiff, resulting in a high probability of intraluminal injury, especially when used in small tortuous arteries. To decrease the risk of such injury, we recommend gentle manipulations while passing the scope and use of the smallest diameter scope possible. We further suggest limited use of the fiberscope, or at least limiting the number of passes in small vessels such as coronary arteries.

Animals↗
PubMed1988

The measurement of phospholipase A2 activity in human myometrium: physiological and pathological implications.

Phospholipase A2 activity was measured in human myometrium obtained at hysterectomy in a group of 41 patients using a double isotope ratio assay based on the liberation of [14-C] oleic acid from 1-palmitoyl-2-[14-C] oleoyl phosphatidylcholine. The enzyme was shown to be calcium independent and to have an optimum pH of 7. There was no significant difference (Mann Whitney U test) in myometrial phospholipase A2 activity between proliferative and secretory phases of the menstrual cycle (ranges: 3.88-30.8 and 0.47-25.85 nmol/mg protein per h respectively) but there was a significant (P less than 0.01) increase in activity in myometrium from uteri with fibroids (median 11.33, range 2.18-30.88 nmol/mg protein per h) compared to those without fibroids (median 6.94, range 0.31-25.85 nmol/mg protein per h). Myometrial phospholipase A2 activity was significantly lower (P less than 0.001) in the 33-40 age group (median 4.71, range 0.31-6.94) compared to the 41-50 age group (median 11.35, range 2.18-30.88 nmol/mg protein per h). In the 51-55 age group phospholipase A2 activity (median 8.71, range 2.5-17.71 nmol/mg protein per h) was not significantly different from that of the other two groups. The increase in activity in the 41-50 age group was not due to the increased incidence of uterine fibroids. These findings suggest that myometrial phospholipase A2 may be important in the pathophysiology of the uterus.

Adult↗
PubMed1988

Cerebrovascular ultrasound imaging.

Advancements in technology have brought noninvasive diagnosis of cerebrovascular disease to a high level of accuracy in a relatively short period of time. Conventional duplex sonography allows precise vessel localization and Doppler quantification. The further refinement of color flow imaging promises to simplify the examination and add considerable confidence to the diagnosis. Regardless of the technology used, ultrasound evaluation of the carotid arteries remains a difficult examination to perform, and excellent results are only possible with meticulous technique. The astute sonographer or sonologist will use all aspects of available ultrasound technology to the fullest. Careful evaluation of a seemingly overwhelming array of parameters will result in an impressive degree of diagnostic accuracy.

Carotid Artery, Internal↗
PubMed1987

Actions of a progestogen on human breast cancer cells: mechanisms of growth stimulation and inhibition.

Medroxyprogesterone acetate (MPA) reduced the proliferation of MCF-7 cells with a maximal response at 100 nM. A subline ('M' cells) resistant to this action remained responsive to antioestrogen but showed a poor response to dexamethasone (DEX). Experiments with mixtures of MPA and DEX showed that MPA acts on wild-type MCF-7 cells through a glucocorticoid as well as a progestogen mechanism. The growth of 'M' cells was stimulated by MPA at 100 nM or greater and the drug increased polyamine concentrations in 'wild-type' as well as 'M' cells. It is suggested that both progestogen and glucocorticoid receptors may mediate the effects of high-dose MPA therapy in breast cancer. The possible stimulation of the growth of some cell types by MPA requires further investigation.

Antineoplastic Agents↗
PubMed1987

Bilateral occlusion of the internal carotid arteries. Presenting symptoms in 74 patients and a prospective study of 34 medically treated patients.

The presenting characteristics of 74 patients with atherosclerotic occlusion of both internal carotid arteries are described. All had suffered either ischaemic hemisphere infarcts (80%) and/or transient ischaemic attacks (80%) involving one (78%) or both (22%) carotid territories. In addition, 10 subjects (14%) incurred recurrent vertebrobasilar or presyncopal episodes, many of which appeared secondary to haemodynamic insufficiency. The incidence of risk factors and concomitant vascular disease was high; 93% gave a history of heavy smoking. Thirty-four subjects were treated conservatively and followed prospectively for a mean of 42 months. Eighteen patients (53%) suffered further cerebrovascular events, an ischaemic event rate of 15% per patient per year. These were isolated transient ischaemic attacks (TIAs) in 7 and stroke in 11 patients. The latter suffered a total of 15 strokes during the follow-up period of 42 months; the annual stroke rate was 13% per patient year. Patients who had presented with ischaemic events involving more than one carotid territory were significantly more prone to subsequent cerebral infarction than those in whom symptoms had been confined to one territory (P less than 0.05). None of the 5 patients with haemodynamic TIAs who were managed conservatively developed a stroke during the follow-up period and their symptoms remitted spontaneously. Deaths per year amounted to 8%. Twenty-four patients (71%) survived, of whom half were either symptom-free or minimally disabled. In this group of preselected patients, which excludes those with severe deficits at presentation, bilateral occlusion of the carotid arteries may be a condition compatible with useful existence.

Adult↗
PubMed1987

Protracted severe immune dysregulation induced by cardiopulmonary bypass: a predisposing etiologic factor in blood transfusion-related AIDS?

A large percentage of patients with blood transfusion related AIDS received their transfusion during cardiac surgery requiring cardiopulmonary bypass. We hypothesized that the procedure of cardiopulmonary bypass (CPB) in patients undergoing cardiac surgery might be associated with severe immune dysregulation and hence predispose this group in particular to the acquisition of blood transfusion transmitted AIDS. T-cell subset enumeration and their ratio (T4/T8) and T-cell function (local GVH reaction) were serially studied before, during, and 1 and 6 days after surgery in 15 patients undergoing cardiac surgery requiring CPB, in 10 patients undergoing cancer resections (CA), and 11 patients without cancer undergoing elective, non-cardiac general surgical procedures (GEN). Compared to the preoperative values, a significant decline (p less than 0.002) in T4/T8 ratios occurred during CPB (1.63 +/- 0.80 vs 2.55 +/- 0.95), during CA (1.26 +/- 0.71 vs 1.81 +/- 0.72), and during GEN procedures (1.18 +/- 0.59 vs 1.64 +/- 0.68). T4, T8, and T4/T8 ratios returned to preoperative values in both the CA and GEN groups by the first postoperative day; in contrast, T4/T8 ratios remained significantly depressed (p less than 0.05) in CPB patients on the first and also on the sixth postoperative days when compared to preoperative values. This sustained depression in T4/T8 ratios is attributable to a significant increase in the proportion of T8 (suppressor cell) subset in the CPB patients which persisted through the sixth postoperative day. In contrast, in CA and GEN, the proportion of T8 subset returned to the preoperative level by the sixth postoperative day.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1986

The inhibition of commitment of mouse erythroleukemia cells by steroids involves a glucocorticoid-receptor mediated process(es) acting at the nuclear level.

Dexamethasone has been shown to inhibit dimethylsulfoxide (DMSO)-induced differentiation of mouse erythroleukemia (or Friend) cells by blocking commitment to terminal erythroid maturation. In this study, we confirmed previous reports indicating the presence of glucocorticoid receptors in murine erythroleukemia cells and examined the mechanism(s) by which steroids block commitment. Untreated murine erythroleukemia cells contain dexamethasone receptors which decrease in number during DMSO-induced cell differentiation. When steroids of different classes (estrogenic, androgenic, glucocorticoid) were tested for inhibition of commitment and for displacement of [3H]dexamethasone from its receptors in DMSO-treated cells, we observed that the glucocorticoids dexamethasone, prednisolone and hydrocortisone, all blocked commitment and substantially displaced [3H]dexamethasone. In contrast, steroids other than glucocorticoids failed to inhibit commitment or displace [3H]dexamethasone. Analysis of kinetics of dexamethasone binding to chromatin revealed that dexamethasone binds to the nucleus via the receptor and preferentially interacts with active chromatin. Inhibition of commitment by dexamethasone persisted in cells released from this agent and reincubated with DMSO in the presence of another glucocorticoid of similar affinity to steroid receptors; inhibition of commitment, however, was not obtained when cells removed from dexamethasone were incubated in the presence of beta-estradiol, progesterone and testosterone. These data indicate that inhibition of commitment of mouse erythroleukemia cells by steroids is associated with binding to glucocorticoid receptors and may involve interactions of steroids and their receptors with regions of chromatin.

Animals↗
PubMed1986

Sciatic nerve palsy complicating umbilical arterial catheterization.

A term newborn infant developed a right sciatic nerve palsy after ischaemic necrosis of the gluteal region following umbilical arterial catheterization. The nerve lesion was believed to be caused by entrapment and compression by scar tissue. Recovery was slow and remained incomplete up to 6 months of age.

Buttocks↗