Search PubMed⌕ Search

Biomedical subjects

L Wong

Publications and source records attributed to L Wong.

At least 271 records · Page 15Linked to original sources
PubMed1978

The developmental response of the ductus arteriosus to oxygen.

We studied the isometric contractile effects of increased PO2 on isolated rings of lamb ductus arteriosus (from three different gestational age groups). When rings were stretched to initial lengths that result in a maximal contractile response for rings in that age group, the oxygen-induced contraction was 5.91 +/- 0.72 g/mm2 (+/-SEM, n = 18) in animals older than 135 days, 5.55 +/- 1.23 g/mm2 (n = 18) in animals between 111 and 130 days, and 3.85 +/- 0.75 g/mm2 (n = 19) in animals between 87 and 110 days. Only in the most immature vessels could a decrease in the tissue's response to oxygen be observed.

Animals↗
PubMed1973

Assay for glutamine synthetase activity.

The use of phosphoenolpyruvate plus pyruvate kinase as an ATP-generating system in the assay for glutamine synthetase activity via the formation of gamma-glutamylhydroxamate from glutamate and hydroxylamine with crude tissue preparations is shown to give values far in excess of the true glutamine synthetase activity of the tissue. This is due to the generation of pyruvate, which reacts with hydroxylamine to give a compound that is chromogenic with the ferric chloride reagent used for measuring gamma-glutamylhydroxamate.

Adenosine Diphosphate↗
PubMed1966

Nursing team.

Explore the source record for details and available documents.

Nursing↗
PubMedDate not supplied

Strategies of information disclosure to Chinese cancer patients in an Asian community.

There is little information available on strategies of information disclosure used by doctors in the care of patients with cancer. This report focuses on the style of disclosure used by doctors when giving diagnostic and prognostic information to patients with cancer. Among 46% of 133 surgeons and radiotherapists interviewed, disclosure of diagnosis involved a sudden approach (information given outright at one sitting). Less commonly used (19%) was a gradual disclosure style. Of the remainder who disclosed, more than half did so through the family or left it to the family to tell the patient. Doctors' specialty and patients' requests for prognostic information dictated disclosure style most frequently. Single people were more likely to have information disclosed to their families than were married people. While anecdotal accounts indicate negative reactions on the part of patients are a major reason for withholding such information, different disclosure style had little effect on doctors' reports of patient reactions to the bad news. Doctors perceived 25% of patients appeared to react 'with depression' but the remaining 75% appeared 'calm'. These results suggest patients are more likely to be told bad news suddenly, and that doctors do not perceive that this impacts too negatively on patients. The high levels of reported preference for information about cancer in Hong Kong (Fielding and Hung, 1996) conflict with actual prevalence patterns. It seems that commonly cited anecdotal reasons for withholding information from cancer patients in Hong Kong are not sustained by the data produced in these studies.

Adolescent↗
PubMedDate not supplied

A review of vascular anastomosis with mechanical aids and nonsuture techniques.

Devices and techniques for nonsuture vascular anastomosis and for suture anastomosis with minimum blood flow interruption are reviewed from their beginnings in the late 19th century through the development of microvascular surgery in the 20th century. The various devices that have been invented fall into 3 basic categories: butt, flanged, and lapped joints. Although the development of microsurgical instruments and the improvement of suture materials have diminished the use of such mechanical aids in recent years, it is hoped that this historical overview will be of interest to investigators involved in the surgery of vessels of various calibers.

Absorption↗
PubMedDate not supplied

Cholelithiasis in the gravid Hispanic population.

Ultrasound examinations were performed to determine the prevalence of cholelithiasis in 585 pregnant Hispanic patients. The ultrasound findings were correlated with age and country of birth. The overall prevalence of gallstones was 5.3%. This is not statistically different from the prevalence of gallstones in age-matched groups from previously published studies not selected for country of birth or ethnic background. We found no statistically significant different in prevalence rates for gallstones between Mexican-born and non-Mexican-born pregnant Hispanic women in the 20-year to 49-year age group. Unlike prior studies, this study does not support the use of increased ultrasound examination for cholelithiasis in a pregnant Hispanic population.

Adult↗
PubMedDate not supplied

Nuclear compartmentalization of aluminum in Alzheimer's disease (AD).

Senile dementia of the Alzheimer type (AD) is a fatal encephalopathy of uncertain etiology. Whether the neurotoxin aluminum plays any role in the AD process in unknown. Here we report an increased amount of aluminum in a chromatin subcompartment, the micrococcal nuclease (MN; EC 3.1.31.1) accessible dinucleosome fraction, in neocortical nuclei isolated from 17 control and 21 AD-affected brains. At these MN-accessible loci we also observe an increase in H1 zero linker histone proteins, DNA-binding proteins which are thought to act as regulators of chromatin compaction. These data support the hypothesis that one deleterious effect of aluminum upon nuclear structure in AD-afflicted brain may be to condense brain chromatin nonrandomly through an interaction with H1 zero linker protein and thereby alter the ability of brain DNA to be effectively transcribed.

Adult↗
PubMedDate not supplied

Reduction of thyroid hormone receptor c-ERB A alpha mRNA levels in the hippocampus of Alzheimer as compared to Huntington brain.

A history of thyroid dysfunction has been cited as a possible risk factor for Alzheimer's disease (AD). Neurologic symptoms displayed by hypothyroid patients resemble, in part, those manifested by Alzheimer patients. To determine if a relationship exists between thyroid hormone receptor message levels and AD, in situ hybridization with tritiated antisense RNA probes for thyroid hormone receptors was used to examine the expression of these genes in Alzheimer and Huntington brain tissue. Message levels for a thyroid hormone receptor highly expressed in brain (c-ERB A alpha) was reduced by 52% in CA1 and 43% in CA2 in Alzheimer hippocampus as compared to Huntington controls. In contrast, message levels for another form of thyroid hormone receptor (c-ERB A beta 1) in Alzheimer hippocampus were not significantly different from Huntington controls. Temporal and cerebellar levels of c-ERB A alpha were elevated by 1.6-fold whereas temporal but not cerebellar levels of c-ERB A beta 1 were elevated 2.0-fold in Alzheimer brain. There was no correlation between thyroid hormone receptor levels and brain weight, autopsy interval, patient age, or the extent of neurofibrillary degeneration. Instead, decreased thyroid hormone receptor mRNA levels in Alzheimer-affected hippocampus were due to an increase in the percentage of neurons expressing lower message levels for these proteins.

Alzheimer Disease↗
PubMedDate not supplied

Drug-induced linear immunoglobulin A bullous disease that clinically mimics toxic epidermal necrolysis.

Drug-induced linear immunoglobulin A bullous disease is a subepidermal blistering disorder that most commonly occurs after exposure to vancomycin. It can clinically mimic toxic epidermolytic necrolysis. We describe an 87-year-old white woman in whom linear immunoglobulin A bullous disease developed while she was taking vancomycin and phenytoin. A few days after the linear immunoglobulin A bullous disease developed, both medications were discontinued. No new bullae developed, and the eruption completely resolved within 2 weeks. The patient was treated with only topical therapy.

Aged↗
PubMedDate not supplied

Urinary arsenic, chromium, and copper levels in workers exposed to arsenic-based wood preservatives.

Urinary excretion of arsenic, chromium, and copper in workers exposed to arsenic-based wood preservatives was examined to evaluate occupational exposure to these chemicals. Spot urine samples were collected from 89 wood treaters and a comparison group of 232 individuals with no known exposure to arsenicals. The results of urinalysis revealed that the wood treaters averaged 103 micrograms arsenic/L while the comparison group averaged 74 micrograms arsenic/L. The mean urinary chromium and copper levels of the wood treaters were 41 micrograms chromium/L and 191 micrograms copper/L compared with 63 micrograms chromium/L and 221 micrograms copper/L for the comparison group. Covariance analysis of urinary arsenic level between the exposed and comparison groups revealed that the adjusted mean arsenic levels of the exposed population (78 to 122 micrograms arsenic/L) were significantly higher than that of the comparison group (72 micrograms arsenic/L). The adjusted mean urinary arsenic levels of these wood treaters, however, were within published normal limits. Analysis of covariance allowed comparison of group means after statistical adjustments for possible confounding variables such as seafood intake and age. The results indicate that urinary arsenic values can provide a useful index of occupational exposure to chromated copper arsenate wood preservatives, when the effects of dietary arsenic are controlled statistically.

Adult↗
PubMedDate not supplied

Mutagenicity of N-nitroso derivatives of carbofuran and its toxic metabolites.

Carbofuran (CF), an insecticide and nematocide, is metabolically oxidized to two less toxic forms, 3-hydroxycarbofuran and 3-ketocarbofuran. The N-nitroso derivatives of carbofuran and its metabolites were synthesized by reaction with nitrite under acidic conditions. Products of the reaction were obtained by extraction, identified by thin-layer chromatography, and purified by silica gel column chromatography. All three nitroso derivatives reacted positively with Gries reagent and gave characteristic triplet absorption spectra (387, 402, and 422 nm). Structural confirmation was by nuclear magnetic resonance and mass spectroscopy. Mutagenicity was determined by the Ames assay method with Salmonella typhimurium strains TA98 and TA100. The nitroso derivatives of all three compounds responded similarly, given a mutation ratio of 45 at 5 micrograms per plate on TA100. In addition, all three produced chromosome aberrations in Chinese hamster ovary (CHO) cells. Only two of the three (nitrosocarbofuran and 3-hydroxynitrosocarbofuran) were also capable of inducing large numbers of sister chromatid exchanges in the same cells. Observed variations in maximum mutagenicity in the Ames test and the ability to induce sister chromatid exchanges in CHO cells are consistent with the stability of the compounds in aqueous solution.

Animals↗
PubMedDate not supplied

Mutant allele frequencies in cats of Minneapolis-St. Paul.

Coat color phenotype frequencies were determined in the cat population of Minneapolis and St. Paul. Mutant allele frequencies are estimated to be p (O) = 0.287, q(a) = 0.742, q(d) = 0.635, q(l) = 0.507, p(S) = 0.288. q(tb) = 0.472, p(W) = 0.016, and q(cs) = 0.214. A substantial number of cats displaying the Siamese coat pattern were found. These cats have a long history in the population.

Alleles↗
PubMedDate not supplied

Newly developed drug delivery system in cancer chemotherapy using direct electric current.

To improve the antitumor effect of chemotherapy on a target organ, we experimentally investigated pharmacokinetic alteration of methotrexate (MTX) induced by an electric current in rats to ascertain whether the local concentration of MTX could be enhanced while reducing the concentration in blood. Six male Wistar rats had platinum electrodes introduced into both kidneys. Three rats were subjected to direct current (3.5 V, 50 microA) for 3 hours, while another three control rats received no current. While providing the current to the treated group, all of the rats were intravenously injected with MTX at a dose of 1 mg/kg. The MTX concentration in urine (excreted from each ureter) and serum was measured by fluorescence polarization immunoassay. Cumulative MTX renal excretion rate was significantly higher in the cathode than anode side in the treated group (p < 0.01). Serum MTX concentration at 0 to 5 min was significantly reduced in the treated group (p < 0.03). The first part of the area under the curve (i.e., alpha curve) was markedly increased in the treated group versus controls (p = 0.05). Electric therapy using a slight direct current could gather anionized MTX to the cathode, while reducing MTX concentration in the serum of experimental rats.

Animals↗