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L Young

Publications and source records attributed to L Young.

At least 127 records · Page 7Linked to original sources
PubMed1996

Asthma, health behaviors, social adjustment, and psychosomatic symptoms in adolescence.

The association of health behaviour, indicators of social adjustment, and psychosomatic symptoms with diagnosed asthma was assessed in a community-based sample of 4550 adolescents in South Western Sydney, Australia. The results of this survey found an asthma prevalence among 11-15-year-olds of 17.5%, being consistent with previous studies. Tobacco use and alcohol consumption were higher among asthmatic compared with nonasthmatic adolescents. Asthmatics reported feeling lonely more often, having a number of negative social perceptions and feelings, and having more frequent psychosomatic symptoms. The findings of the study suggest that adolescents with asthma represent an important vulnerable group of school children. Asthma education may need a greater life-style change focus, besides asthma self-management training.

Adolescent↗
PubMed1996

Use of pH 9.5 Tris-HCl buffer containing 5% urea for antigen retrieval immunohistochemistry.

Successful antigen retrieval (AR) immunohistochemistry is dependent on the temperature, heating time, and pH value of the AR solutions. There is no single standardized AR solution, however, that is suitable for all antibodies "routinely" used in surgical pathology for immunostaining archival tissue sections. We tested a variety of AR solutions varying in pH value, chemical composition, and molarity. Based upon preliminary results, we compared three AR solutions: 0.1 M Tris-HCl buffer, pH 9.5, containing 5% urea, 0.1 M Tris-HCl buffer pH 9.5 without urea, and citrate buffer, pH 6.0. Each AR solution was tested with a panel of 34 antibodies using microwave heating for antigen retrieval. The heating conditions were standardized at 10 min and an automated stainer was used to standardize the immunostaining method. The Tris-HCl containing urea was superior to pH 6.0 citrate buffer for 22 antibodies. In 12 cases, Tris-HCl with urea was also superior to Tris-HCl alone. In 12 cases, the intensity was similar for all three retrieval solutions. The staining obtained with Tris-HCl with urea was equal to or better than with pH 6.0 citrate buffer in all cases. The Tris-HCl with urea solution is satisfactory for AR of most antibodies employed in routine surgical pathology.

Antigens↗
PubMed1996

Comparative study of antigen retrieval heating methods: microwave, microwave and pressure cooker, autoclave, and steamer.

We present a study comparing the most popular heating methods currently used for antigen retrieval (AR) immunostaining: the microwave oven, microwave with pressure cooker, autoclave, and steamer heating. A panel of 21 antibodies was tested on formalin fixed, paraffin embedded sections using these heating methods and Tris-HC1 buffer, pH 9.5, plus 5% urea as the AR solution. Three observers independently evaluated the intensity of AR immunostaining. All heating methods yielded good results for AR immunostaining. There were only minor differences among the heating methods for AR when the optimal concentration of primary antibody for normal immunostaining was used; however, background staining may occasionally be troublesome if antibodies are not retitrated and diluted further for use on tissues after AR. Significant differences were observed only after further dilution of the primary antibodies: the microwave pressure cooker, extended microwave heating (5 min x 4) and autoclave heating then showed a similar intensity of staining that was stronger than results obtained with the steamer (20 min) or regular microwave heating (5 min x 2). Extension of the steamer heating time, however, yielded equivalent results. This study indicates that different heating methods can yield similar intensities of AR immunostaining if the heating times are adjusted appropriately. It is noteworthy that, in general, the adjusted conditions for maximal retrieval differ from those most widely cited in the literature, or recommended by manufacturers. That several heating devices may provide similar results permits the use of different AR heating methods according to the equipment available. This study also is an early step in standardizing the AR immunostaining protocol by providing uniform conditions for "maximal retrieval" as a common end point for all laboratories.

Antigens↗
PubMed1996

The atypical neuroleptic profile of the glycine/N-methyl-D-aspartate receptor antagonist, L-701,324, in rodents.

The present study has examined the glycine/N-methyl-D-aspartate antagonist, L-701-324 [7-chloro-4-hydroxy-3-(3-phenoxy)-phenyl-2 (H)quinolone] in rodent behavioral tests commonly used to predict antipsychotic potential and side effect liability in humans. Pretreatment with L-701,324 dose-dependently antagonized amphetamine-induced hyperactivity in the mouse (ED50 = 1.12 +/- 0.45 mg/kg p.o.), an effect which was similar to that of the classical neuroleptic, haloperidol, and the atypical neuroleptic, clozapine. In addition, p.o. administration of L-701,324 (2.5 or 5 mg/kg) attenuated the hyperactivity response induced by amphetamine infusion into the rat nucleus accumbens. In contrast to haloperidol, however, stereotyped sniffing and licking/biting, induced by either the systemic administration of apomorphine or infusion of amphetamine into the striatum, was not altered in rats pretreated with L-701,324 (30 or 100 mg/kg p.o.). Furthermore, L-701,324 failed to impair spontaneous locomotor activity or induce catalepsy in the mouse at doses > or = 100 mg/kg. Although a significant reduction in spontaneous activity was observed in rats pretreated with L-701,324, the minimum effective dose (10 mg/kg p.o.) was 2-fold greater than that which abolished amphetamine-induced hyperactivity in this species. Thus, L-701,324 selectively blocks behaviors associated with the activation of the mesolimbic dopamine system suggesting that glycine/N-methyl-D-aspartate receptor antagonists may offer a novel approach to the treatment of schizophrenia in humans.

Amphetamine↗
PubMed1996

Redesigning the RN and NA roles.

To ensure optimal utilization of RNs, the nursing care delivery system in a surgical nursing division assessed the tasks that could be delegated to ancillary personnel. Nursing assistants completed competency-based training and after six months, several positive outcomes were evident: dramatic decreases in overtime, improved patient care and increased patient and staff satisfaction.

Humans↗
PubMed1996

Air transport of obstetric critical care patients to tertiary centers.

OBJECTIVE: To evaluate critical care diagnoses and their frequency in an air transport situation. STUDY DESIGN: A retrospective review was done of all obstetric air transports performed by Samaritan AirEvac to tertiary hospitals in Phoenix, Arizona, from January 1, 1990, to August 31, 1991. RESULTS: In the 20-month study period, 1,541 maternal transports were performed. Critical care diagnoses were found in 360 (23.4%) of the patient. The following categories were used: hypertensive crisis, 188/360 (52%); hemorrhage, 131/360 (36%); trauma, 21/360 (6%); and respiratory compromise, 11/360 (3%). CONCLUSION: Critical care diagnoses represented about 25% of all obstetric air transports in this study. Our transport team is made up of an obstetric flight nurse and another team member (adult trauma nurse, neonatal flight nurse, flight respiratory therapist of flight paramedic). Skill in both obstetric diagnosis and management and in critical care necessary in these situations.

Air Ambulances↗
PubMed1996

Rat immunogenicity assay of inactivated poliovirus.

A rat immunogenicity assay for IPV potency was validated and applied to routine vaccine testing as a potential alternative to the CFR Monkey Potency Assay. Potencies of pure trivalent polio, various combinations and experimental vaccines were tested with a view of producing a single dilution assay.

Animal Testing Alternatives↗
PubMed1996

Binge eating disorder and the night-eating syndrome.

OBJECTIVE: To determine in three samples of obese women the prevalence of two eating disorders--binge eating disorder and the night-eating syndrome. METHOD: Interviews utilizing standard criteria. For binge eating disorder: the consumption of large amounts of food in a discrete period of time together with a subjective sense of loss of control and no vomiting or laxative abuse. For the night-eating syndrome: morning anorexia, evening hyperphagia and insomnia. Determining the rate of binging among patients receiving a placebo. SUBJECTS: (1) 102 viewers of a television show describing binge eating disorder; (2) 50 participants in a trial of medication for this disorder and (3) 79 participants in a weight reduction program. RESULTS: In the television sample 19.6% of respondents and in the weight reduction sample 7.6% met criteria for binge eating disorder; all subjects in the medication sample met criteria. During a 4-week placebo period average binge frequency fell from 6.0 to 1.7 binges per week. The night-eating syndrome was manifested by 13.7% of the television sample, 8.9% of the weight reduction sample and 15.0% in the medication trial sample. There was little overlap between the two disorders. CONCLUSIONS: Binge eating disorder is far less frequent than has been believed on the basis of questionnaire studies and it is highly responsive to placebos. Frequency of the night-eating syndrome is comparable to that of binge eating disorder. Future studies should assess binge eating disorder by interview rather than by self-administered questionnaire.

Adult↗
PubMed1995

The risk for transmission of Mycobacterium tuberculosis at the bedside and during autopsy.

OBJECTIVE: To emphasize the differing infectious potentials of a patient with tuberculosis. SETTING: Hospital ward and autopsy room. DESIGN: An epidemiologic investigation of tuberculin skin test conversions in a clinical setting and during autopsy when results of tuberculin tests done before exposure were available for all participants. MEASUREMENTS: Tuberculin skin test results after the discovery of tuberculosis exposure from a patient with unsuspected tuberculosis for comparison with the test results before exposure; culture of sputum and autopsy material for Mycobacterium tuberculosis; and DNA fingerprinting of organisms. INTERVENTION: Preventive therapy for persons with skin test conversion. RESULTS: None of the 40 skin test-negative health care workers caring for the patient for 3 weeks on an open medical ward showed a skin test conversion, even though they had not used respiratory precautions. By contrast, among personnel present during the 3-hour autopsy, the test results of all five nonreactors converted from negative to positive (mean reaction, 24 mm). Two of these persons had a positive sputum culture 8 weeks later. The DNA fingerprints of all three isolates were identical. CONCLUSIONS: A patient who did not transmit tuberculosis before death released a prodigious number of tubercle bacilli during autopsy.

Air Microbiology↗
PubMed1995

Emergency contraception--why women don't use it.

AIM: The aim of the study was to examine knowledge of and perceived availability of the emergency contraceptive pill as well as reasons for its non use. METHODS: One hundred women each attending Epsom day unit or the Auckland medical aid clinic in Auckland seeking termination of pregnancy, and 100 women seeking contraceptive advice from the Alice Bush centre in Auckland, were asked to take part in the study. RESULTS: At Alice Bush centre 57% of women had previously used the emergency contraceptive pill compared with 43% women at Epsom day unit and 32% women at Auckland medical aid clinic. Only 7% of women attending Epsom day unit or Auckland medical aid clinic had used the emergency contraceptive pill in the month they conceived. When asked why they had not used the emergency contraceptive pill 38% of respondents said they had not heard of it and 41% did not know where to obtain it. Pacific Island women were least likely to have heard of it. Approximately 50% knew the correct time interval for using the emergency contraceptive pill. Sixty two percent attending the abortion clinics would have used the emergency contraceptive pill if they had a supply at home and 57% stated they would have used it if it was available over the counter through pharmacies. CONCLUSIONS: The discrepancy between the numbers of women who knew of the emergency contraceptive pill (72%) and the numbers who used it to try to prevent pregnancy (7%) indicates that there are barriers to obtaining and using the emergency contraceptive pill. This study demonstrated a lack of knowledge of the emergency contraceptive pill in women attending the abortion clinics. The majority of women seeking termination of pregnancy would have used the emergency contraceptive pill if they had it available at home or over the counter through a pharmacy. Doctors prescribing the pill and barrier methods of contraception should consider providing a supply of emergency contraceptive pill at the same time and consideration should be given to over the counter prescribing of the emergency contraceptive pill in New Zealand.

Adult↗
PubMed1995

Superoxide radical and xanthine oxidoreductase activity in the human heart during cardiac operations.

BACKGROUND: The results of clinical trials of xanthine oxidoreductase inhibition in cardiac surgery are encouraging, although studies have failed to localize the enzyme to the human heart and to localize free radical activity to fresh human heart. METHODS: We adapted a histochemical staining technique based on the reduction of nitro blue tetrazolium to formazan by superoxide radical. In six samples of right atrium graded blindly on a scale of 0 through 4, strong staining (median grade, 3) of the microvasculature was seen. This was blocked by allopurinol in paired sections (median grade, 1; p < 0.01). Chemiluminescence can be used as an index of superoxide radical activity. Atrial samples were taken from 13 patients at five time points during coronary bypass grafting and placed in buffered luminol. Then chemiluminescence was measured. RESULTS: A 15-fold rise in chemiluminescence (295.93 +/- 39.47 mV) was demonstrated during reperfusion compared with the control value (19.06 +/- 0.47 mV). Chemiluminescence at 1 minute after release of the cross-clamp was significantly higher (p < 0.05) by analysis of variance versus values obtained before bypass and 1 minute before and 30 minutes after reperfusion. CONCLUSIONS: In this study we have identified superoxide radical activity and a possible generating system (xanthine oxidoreductase) in the human heart.

Aged↗
PubMed1995

Postinfectious purpura fulminans caused by an autoantibody directed against protein S.

OBJECTIVE: To determine the mechanism responsible for idiopathic purpura fulminans, we investigated the procoagulant and anticoagulant pathways in five consecutive patients, four after varicella, and the fifth after a nonspecific infection. METHODS: Procoagulant and anticoagulant factors, including protein C, protein S, and antithrombin III, were measured by quantitative or functional assays. Anti-protein S autoantibodies were identified by dot blotting and Western blotting, and quantified serially by enzyme-linked immunosorbent assay. Clinical and laboratory data were collated retrospectively. RESULTS: In each case the disease began 7 to 10 days after the onset of the precipitating infection, with rapidly progressive purpura leading to extensive areas of skin necrosis. The illness was complicated by impaired perfusion of limbs or digits (two patients), peripheral gangrene resulting in an above-knee amputation (one patient), and major organ dysfunction caused by thromboembolic phenomena involving the lungs (two patients), the heart (one patient), or the kidneys (one patient). Protein S levels were virtually undetectable at the time of admission and failed to respond to infusions of fresh frozen plasma, despite correction of other procoagulant and anticoagulant factors. All five children had anti-protein S IgM and IgG autoantibodies, which persisted for less than 3 months after admission. Decline in the anti-protein S IgG antibody concentration was associated with normalization of the plasma protein S levels. CONCLUSIONS: Autoimmune protein S deficiency may be a common mechanism causing postinfectious idiopathic purpura fulminans. Recognition of the pathophysiologic mechanism may provide a rational basis for treatment. Immediate heparinization, infusions of fresh frozen plasma, and, in cases complicated by major vessel thrombosis, the use of tissue-type plasminogen activator may limit thromboembolic complications.

Acute Disease↗
PubMed1995

The effect of high-dose medium- and long- term progestogen exposure on endometrial vessels.

A total of 19 paraffin-embedded endometrial tissue blocks were obtained from high-dose progestogen-exposed patients. A labelled streptavidin-biotin-alkaline phosphatase method was used with antibodies against von Willebrand factor (vWF) and CD34. The density of CD34 and vWF positive (CD34+ and vWF+) vessels in progestogen-exposed endometria (103 +/- 9.6/mm2 and 106 +/- 8.7/mm2) was significantly lower than in endometria from women with normal cycles (169 +/- 9.3/mm2 and 136 +/- 8.0/mm2) (P < 0.05). In women with normal menstrual cycles the concentration of CD34+ vessels was significantly higher than the number of vWF+ vessels (P = 0.0001). By comparison, the concentration of CD34+ vessels was similar to the concentration of vWF+ vessels in progestogen-exposed endometria. The ratios of vascular density as determined by vWF+ and CD34+ staining the control and progestogen groups were 0.81 and 1.05 respectively (P = 0.0001). Dilated venules were seen in the progestogen group. This study has demonstrated firstly that CD34 antibody detected the endothelial cells in a higher proportion of small endometrial vessels than vWF, and secondly that high-dose progestogen exposure significantly decreased the density of microvessels and increased the number of dilated venules in endometrium.

Antigens, CD↗
PubMed1995

Neuromuscular blocking profile of the vecuronium analogue, Org-9487, in the rat isolated hemidiaphragm preparation.

1. The neuromuscular effects of the short-acting aminosteroid muscle relaxant Org-9487 have been studied in the in vitro rat phrenic nerve/hemidiaphragm preparation by use of twitch tension and electrophysiological recording techniques. 2. Org-9487 (5-100 microM) produced a concentration-dependent decrease in the amplitude of twitches (0.1 Hz) and tetanic contractions (50 Hz) evoked by motor nerve stimulation. The compound produced fade of force during both 50 Hz stimulation and train-of-four stimulation at 2 Hz, indicating a prejunctional component of action. 3. Anticholinesterases only partially reversed the effect of Org-9487 on twitch responses. This was possibly because, at the concentrations required to block twitches in the rat, Org-9487 itself was found to possess significant anticholinesterase activity. 4. Org-9487 (3 microM) increased the rundown of endplate current amplitudes during a 2 s train of 50 Hz nerve stimulation. This was because Org-9487 increased the quantal content of the first endplate current in the train without affecting acetylcholine release towards the latter part of the train. 5. Org-9487 (10 microM) produced a voltage-dependent decrease in the time constant of decay of endplate currents at 32 degrees C and 0.5 Hz, indicative of a block of endplate ion channels. The blocking rate constant increased with membrane hyperpolarization.

Acetylcholine↗
PubMed1995

Antigen retrieval immunohistochemistry under the influence of pH using monoclonal antibodies.

Antigen retrieval (AR) incorporating high-temperature microwave (MW) heating of tissue sections before immunostaining is a revolutionary technique that can unmask the antigens in formalin-fixed tissue sections, thus making them available for immunohistochemical staining. Although high temperature is believed to be the primary mechanism in retrieval of antigens, a variety of chemical solutions have been tested to define an optimal AR solution. We tested the hypothesis that pH of the AR solution may influence the quality of immunostaining by using seven different AR buffer solutions at a series of different pH values ranging from 1 to 10. We evaluated the staining of monoclonal antibodies to cytoplasmic antigens (AE1, HMB45, NSE), nuclear antigens (MIB-1, PCNA, ER), and cell surface antigens (MT1, L26, EMA) on routinely formalin-fixed, paraffin-embedded sections under different pH conditions with MW heating for 10 min. The intensity of immunostaining was graded in a blinded fashion. The pH value of the AR buffer solution was carefully measured before, immediately after, and 15 min after the AR procedure. The influence of pH on AR immunohistochemical staining can be summarized into three patterns. Some antigens (L26, PCNA, AE1, EMA, and NSE) showed excellent retrieval throughout the pH range. Other antigens (MIB1 and ER) showed strong intensity of immunohistochemical staining at very low pH and at neutral to high pH, but a dramatic decrease in the intensity of the AR immunostaining at moderately acidic pH (pH 3-6). Still others (MT1 and HMB45) showed increasing intensity of the AR immunostaining with increasing pH, but only weak immunostaining at low pH. Among the seven buffer solutions at any given pH value, the intensity of AR immunostaining was very similar. However, Tris-HCl buffer tended to produce better results at higher pH, compared with other buffers. Although high-temperature heating is believed to be the most important factor for the AR technique, the pH value of the AR solution is an important co-factor for some antigens. Optimization of the AR system should therefore include optimization of the pH of the AR solution. Our results indicate that AR immunostaining of Tris-HCl or sodium acetate buffer at pH 8-9 may be suitable for most antigens, although certain nuclear antigens show optimal staining at low pH.

Antibodies, Monoclonal↗