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Biomedical subjects

J Austin

Publications and source records attributed to J Austin.

At least 55 records · Page 3Linked to original sources
PubMed1997

Detection of RAPD markers correlated with chloroquine resistance in Plasmodium falciparum.

We described the use of the random amplified polymorphic DNA (RAPD) technique on Plasmodium falciparum DNA to detect genetic markers for chloroquine-resistant strains. Fourteen RAPD primers were tested, three of which generated banding patterns correlated with chloroquine resistance. To measure this correlation, the RAPD profiles were analyzed using the Nei and Li similarity coefficient. Detection of distinctive RAPD bands allowed us to synthesize specific PCR primers to be used on whole-blood samples. Two primer sets were synthesized and tested on sensitive and resistant strains for their ability to amplify the DNA fragment corresponding to the RAPD marker. These results suggest that RAPD and PCR techniques can be used as powerful tools for the detection of genetic markers associated with drug resistance.

Animals↗
PubMed1996

Health outcomes of two telephone interventions for patients with rheumatoid arthritis or osteoarthritis.

OBJECTIVE: The effects of treatment counseling or symptom monitoring telephone intervention strategies on the health outcomes of patients with rheumatoid arthritis (RA) or osteoarthritis (OA), compared with usual care, were assessed. METHODS: A 3-group, randomized, controlled 9-month trial was conducted incorporating 405 patients with RA or OA and using the Arthritis Impact Measurement Scales (AIMS2) as the outcome measure. RESULTS: Analyses of covariance showed that the AIMS2 total health status of the treatment counseling group (effect size = 33, P < 0.01), but not the symptom monitoring group (effect size = 0.21, P = 0.10), was significantly improved, compared with usual care, for both RA and OA patients. The specific types of benefits differed significantly between RA and OA patients. The mean number of medical visits by OA patients in the treatment counseling group was also significantly reduced (P < 0.01). CONCLUSION: Telephone contact using the treatment counseling strategy produced significant, but different, health status benefits for RA and OA patients. The symptom monitoring strategy produced modest benefits.

Adult↗
PubMed1996

The standard deviation as an informative measure of variability in reporting interobserver agreement means.

The range is the measure of variability typically presented with the means of interobserver agreement scores of behavioral data. However, the range by itself yields little information about the individual interobserver agreement scores before they were averaged. The standard deviation, on the other hand, is a measure of variability that provides the researcher and reader with information regarding the dispersion of scores, allowing a more thorough interpretation of the interobserver agreement mean. The case is presented for the adoption of the standard deviation as an adjunct to the range in reporting the mean of interobserver agreement scores.

Behavior Therapy↗
PubMed1995

c-erbB-2/neu oncogene and Ki-67 analysis in the assessment of palatal salivary gland neoplasms.

To evaluate the role of the Ki-67 proliferation antigen and c-erbB-2/neu oncogene expression in the clinical assessment of salivary gland tumors, we followed up 71 patients with minor salivary tumors of the palate. All benign neoplasms (n = 18) showed low Ki-67 scores (< 12%), whereas 26% (14 of 53) of malignant neoplasms manifested high Ki-67 scores (> 12%). A significant statistical difference between Ki-67 scores for benign and malignant neoplasms was observed (p < 0.001). Ki-67 index also correlated significantly with malignant tumor grade (p = 0.04) and patient survival (p = 0.02). Only 1 of the 18 benign tumors had c-erbB-2/neu oncogene overexpression. A significant difference between c-erbB-2/neu overexpression in benign and malignant tumors was observed (p = 0.01). Overexpression of c-erbB-2/neu oncogene was noted in 38% (16 of 42) of malignant tumors and was significantly associated with aggressive tumor behavior (p < 0.001). Multivariate analysis of significant factors revealed that gender, tumor stage, and c-erbB-2/neu oncogene overexpression were jointly predictive of survival. Our data indicate that although the Ki-67 proliferating antigen and c-erbB-2/neu oncogene expression may reflect certain intrinsic biologic properties of these neoplasms, only c-erbB-2/neu overexpression is significantly associated with their biologic aggression.

Adolescent↗
PubMed1995

Epithelial-myoepithelial carcinoma of salivary glands. A clinicopathologic, DNA flow cytometric, and immunohistochemical study of Ki-67 and HER-2/neu oncogene.

Thirty-one salivary gland epithelial-myoepithelial carcinomas from 26 patients were studied by DNA flow cytometry, and immunostaining for Ki-67 and HER-2/neu oncogene product. The results were correlated with clinicopathologic factors and patient outcome. The tumor most commonly involved the parotid gland, and mainly affected patients in their 6th to 8th decades. The clinical course was characterized by a high incidence of local recurrence (50%) and not infrequent distant metastasis (25%). None of the patients in this cohort died of disease. DNA content analysis revealed 21 neoplasms with DNA diploidy and 5 tumors with DNA aneuploidy; all aneuploid cases were near-diploid (hyperdiploidy) and showed low proliferative activity. All aneuploid and 60% of the diploid neoplasms developed recurrences and/or metastases. Immunohistochemical analysis of Ki-67 proliferation markers also showed low overall growth fractions. Interestingly, Ki-67 immunoreactivity was largely restricted to myoepithelial cells, suggesting a central role for this cell in the development of these tumors. HER-2/neu oncogene analysis failed to demonstrate overexpression in any of the tumors examined. This study indicates that epithelial-myoepithelial carcinoma is a low grade malignant neoplasm with a high propensity for recurrence. HER-2/neu oncogene and Ki-67 offer no additional advantages over current factors in the biologic evaluation of these neoplasms. DNA aneuploidy may allow for the identification of a subset of tumors that is more prone to recurrence and metastasis, but further studies with extended follow-up are needed.

Adolescent↗
PubMed1994

Cell contact regulates neuroblast formation in the Caenorhabditis elegans lateral epidermis.

A single line of epidermal seam cells lies along each side of the nematode C. elegans. During normal development, one of these cells, V5, produces a neuroblast that will give rise to a sensory structure, the postdeirid. If seam cells located either anterior or posterior to V5 are ablated however, this neuroblast formation is blocked. Because of this requirement for the presence of adjacent seam cells, we have asked whether V5's ability to produce a neuroblast depends on direct contact with its seam cell neighbors. We find that direct contact between seam cells is required for commitment to neuroblast production. Seam cells lose and reform their contacts with each other as they go through rounds of cell division during larval development. Signaling required for neuroblast formation occurs when the seam cells make contact after their first round of division. If this contact is prevented, no neuroblast is made; when it is delayed, the time of signaling is also delayed. The characteristics of these signals suggest that a seam cell must be part of a continuous epithelium in order to develop normally and that signaling may occur via a cell recognition/cell adhesion pathway. The effect of seam cell ablations on neuroblast formation is altered in mab-5(-) animals, suggesting that this HOM-C gene is part of the pathway by which seam cell signaling controls the decision to make a postdeirid neuroblast.

Animals↗
PubMed1993

A homeotic gene cluster patterns the anteroposterior body axis of C. elegans.

In insects and vertebrates, clusters of Antennapedia class homeobox (HOM-C) genes specify anteroposterior body pattern. The nematode C. elegans also contains a small cluster of HOM-C genes, one of which has been shown to specify positional identity. Here we show that two additional C. elegans HOM-C genes also specify positional identity and that together these three HOM-C genes function along the anteroposterior axis in the same order as their homologs in other organisms. Thus, HOM-C-based pattern formation has been conserved in nematodes despite the many differences in morphology and embryology that distinguish them from other phyla. Each C. elegans HOM-C gene is responsible for a distinct body region; however, where their domains overlap, two HOM-C genes can act together to specify the fates of individual cells.

Amino Acid Sequence↗
PubMed1993

Warm blood cardioplegia.

Between 1990 and 1992, 346 consecutive patients underwent coronary artery bypass procedures. Ninety-eight patients (group A) from 1990 served as historical controls, and 248 patients (group B) from 1991 to 1992 served as a prospective, consecutive cohort for statistical comparison. The two groups varied in the type of myocardial protection used: intermittent cold crystalloid cardioplegia was used in group A and continuous warm blood cardioplegia in group B. (Two patients in group A received intermittent cold blood cardioplegia, and these 2 patients are grouped with the crystalloid group for the sake of convenience. The presence or absence of these 2 patients did not alter the group A statistics in any noticeable manner). Class IV high-risk groups demonstrated a 63% reduction in mortality (p = 0.07), and overall group B experienced a 28% reduction in mortality (4.4% versus 6.1%; p = not significant), an 86% reduction in perioperative myocardial infarction rate (1.6% versus 12.2%; p < 0.05), a 20% reduction in postoperative bleeding (275 versus 345 mL.day-1.m-2), and a marked reduction in reentry rates (p = 0.05). Also noted was a 32% reduction in postoperative ventilation requirements (25 versus 37 hours; p = 0.05). Less inotrope was required and intraoperative stroke was not seen in the patients with warm blood cardioplegia. Group B patients were less likely to have development of complex postoperative arrhythmias. Ventricular fibrillation at unclamping was noticeably rare (2.0% in group B versus 84% in group A; p < 0.05). The average group B heart resumed sinus rhythm 72 seconds after declamping.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Further studies of the mixed acetals of nucleosides.

We reported in 1988 on a new nucleoside modification reaction: the exocyclic amino groups of (d)adenosine and (d)cytidine react rapidly at ambient temperature with acetaldehyde and alcohols to give stable mixed acetals (N-ethylethoxy-acetal). NH2 + O = CH(CH3) + ROH-->NH-CH(CH3)-O-R + H2O. Here we report in detail on the occurrence of this reaction in very dilute aqueous solution (ie under biological conditions), on its mechanism and kinetics, on the mixed acetal formation with other aldehydes and other nucleic acid components, and on the question of whether these adducts are mutagenic.

Acetaldehyde↗
PubMed1993

Blood pressure during sustained inhibitory breathing in the natural environment.

Previous studies reported that breathing frequency of laboratory dogs decreased preceding the onset of an avoidance task and that this decrease was accompanied by increases in blood pressure and decreases in heart rate. Low frequency/normal tidal volume breathing has also been observed in ambulatory humans, but the cardiovascular concomitants of this inhibitory breathing pattern remain to be determined. The present study recorded blood pressure and heart rate in humans during periods of inhibitory breathing in the natural environment. Systolic and mean pressure were higher during inhibitory breathing than at other times, but no differences in diastolic pressure or heart rate were observed. Inhibitory breathing was differentially associated with the workplace and with social situations. Thus, major components of a physiological pattern that predisposes laboratory animals to sodium-sensitive experimental hypertension have now been observed to covary in ambulatory humans. Whether inhibitory breathing in the natural environment is a correlate or a cause of elevated blood pressure remains to be determined.

Adult↗
PubMed1993

Increasing recycling in office environments: The effects of specific, informative cues.

We investigated the effects of prompts on the recycling behavior of approximately 217 faculty, staff, and graduate students in two academic departments of a large university. During the intervention, two signs were posted in each department. One sign prompted recycling (posted above the recycling receptacle), and the other sign prompted proper disposal of trash (posted above the trash receptacle). Results of a multiple baseline design across the two departments indicated that the sign prompt increased recycling behavior. Installation of the sign prompts in close proximity to receptacles in Department A resulted in a 54% improvement over baseline. Posting of sign prompts over containers 4 m apart in Department B resulted in a 17% improvement, whereas positioning the signs and receptacles in close proximity resulted in a 29% improvement over baseline.

Journal Article↗
PubMed1992

'Something for your pain, dear'?

As a student nurse in the middle '70s, I recall being struck by the unsophisticated and somewhat haphazard way pain relief following surgery was managed. I had been expecting to receive tuition in the clinical environment, as my classroom studies had not included any reference to pain or pain management. I was, like other staff on the ward, largely ignorant of pain physiology and pain psychology, and accustomed to making subjective judgement of other people's pain, based largely on my own misconceptions and inappropriate inherited attitudes. This, in turn, led to analgesia being offered in much the same way as a 'nice cup of tea', 'Something for your pain, dear?' Standard doses of analgesia were prescribed for the majority of patients via intramuscular or oral routes, and the actual dose administered was randomly selected by nursing staff and delivered at varying intervals. Thankfully, over the last few years, things have started to change.

Humans↗
PubMed1992

The effects of inhaled albuterol and oral theophylline on gastroesophageal reflux in patients with gastroesophageal reflux disease and obstructive lung disease.

Patients with gastroesophageal reflux disease may have pulmonary symptoms due to repeated aspiration of gastric contents or reflex bronchospasm during a reflux event. Oral bronchodilators are known to worsen gastroesophageal reflux and may lead to vicious cycle when gastroesophageal reflux causes bronchospasm. The effect of inhaled bronchodilators on gastroesophageal reflux is unknown. We compared the severity of gastroesophageal reflux in patients with documented gastroesophageal reflux disease and obstructive lung disease while they were taking inhaled albuterol or oral theophylline. Nine patients with gastroesophageal reflux disease had 24-hour esophageal pH studies on two separate days approximately 1 week apart. On one study day, the patients received 0.5 mg of albuterol in 2.5 mL of normal saline vias hand-held nebulizer, four times a day. On the other day, the patients received sustained-release theophylline, 200 mg twice a day, or in a dosage taken previously to achieve a serum theophylline level of 55 to 110 mumol/L. The patients had 40% reduction in the total time the pH was less than 4.0 with albuterol than with theophylline (9.7% vs 16.1%). Seven patients had less gastroesophageal reflux while taking albuterol, and two patients had essentially no change. Patients with gastroesophageal reflux disease, who require bronchodilator therapy for obstructive lung disease, have less reflux with inhaled albuterol.

Administration, Inhalation↗
PubMed1991

The W element is a positive regulator of HLA-DRA transcription in various DR+ cell types.

The W and P elements are cis-acting transcriptional regulators of the human class II MHC gene HLA-DRA necessary for maximal promoter activity in DR+ B cells. Proteins that bind specifically to W may mediate promoter activity from a DNA segment containing W and P (W/P). In this report, we demonstrate that a -143 to -123 bp region that lacks P is sufficient to mediate the W elements function and to bind the W proteins W-B1 and W-B2 in the Raji B-lymphoblastoid cell line. In contrast to previous reports, we find that W/P is not a B cell-specific element; rather that its promoter activity parallels active transcription of the endogenous DRA gene. In addition, we show that tissue-restricted regulation by W/P is not correlated with the ubiquitous (W-B1) and lymphoid-specific (W-B2) distribution of the W binding proteins. We suggest that mechanisms in addition to binding to W may account for W/P-dependent transcriptional activation in DR+ cells.

B-Lymphocytes↗