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Biomedical subjects

J Edwards

Publications and source records attributed to J Edwards.

At least 109 records · Page 6Linked to original sources
PubMed1994

Increased risk for type I (insulin-dependent) diabetes in relatives of patients with alopecia areata (AA).

The prevalence of various chronic diseases was compared in 517 individuals with alopecia areata, and 2,969 of their first degree relatives. As previous reports have suggested an increased incidence of diabetes in relatives of patients with alopecia areata, special attention was given to the prevalence of Type 1 and Type 2 diabetes in the patients and in their relatives. Several immunologic diseases were increased in alopecia probands and relatives. Thyroid disease, vitiligo, Addison disease, and pernicious anemia were more prevalent in probands and in their relatives than in the general population. Specifically, a high rate of thyroid disease was found in probands (14.7%) and in their first degree relatives (4.2%). Only one proband had Type 1 diabetes, yet there were 14 sibs with Type 1 diabetes. Thus, Type 1 diabetes was significantly more prevalent in the sibs (1.2%) than in either the probands with alopecia (0.2%), or the general population (0.12-0.25%) (P < 0.05)). In contrast, Type 2 diabetes was not more common in probands or in sibs than in the general population. These data suggest that alopecia areata protects against Type 1 diabetes in predisposed individuals. The high rate of thyroid disease suggests that screening probands and first degree relatives for thyroid disease should be considered.

Addison Disease↗
PubMed1994

Cytotoxic T-cell activity antagonized by naturally occurring HIV-1 Gag variants.

Most asymptomatic individuals infected with HIV-1 have a cytotoxic T lymphocyte (CTL) response to the virus Gag proteins which can be demonstrated in vitro. Epitopes have been mapped in p17 Gag and p24 Gag restricted by HLA-B8 (p17-3 and p24-13) and -B27 (p24-14). Viruses isolated from patients who make CTL responses to these peptides vary within the genetic sequences encoding these epitopes and some mutations lead to reduction in killing activity in vitro. This was attributed to either failure of the variant epitope to bind major histocompatibility complex class I or failure of T-cell receptors to bind the presented peptide. But peptide variants of class I-restricted epitopes cause 'antagonism', that is, the presence of a variant epitope (in the form of peptide) inhibits normal lysis of targets presenting the original epitope. This mirrors similar findings in class II-restricted systems. Here we report that naturally occurring variant forms of p17-3, p24-13 and p24-14 may cause antagonism of CTL lines derived from the same individuals. The effect is present if the epitopes are derived from synthetic peptides and when they are processed from full-length proteins expressed by either recombinant vaccinia constructs or replicating HIV.

Amino Acid Sequence↗
PubMed1994

Screening for colorectal cancer using an immunochemical test for faecal occult blood: results of the first 2 years of a South Australian programme.

This paper reports an evaluation of the first 2 years of a South Australian screening programme for colorectal cancer which was established in 1988 by the Institute of Medical and Veterinary Science. The programme uses an immunochemical test for faecal occult blood. Based on 1 year of follow-up, over the period of this analysis there were 24 cancers and 99 adenomas detected in 6208 participants, and the estimated sensitivity and specificity of the test (for colorectal cancer) were 82.8 and 95.9%, respectively. In many cases the test was used to detect recurrence of disease in individuals with a previous diagnosis of colorectal cancer. The estimated predictive value of a positive test for colorectal cancer in this population was 7.5%. Results suggest that participants belonged to higher-than-average socio-economic groups and were more likely than the general population to have a family history of colorectal cancer. Almost one-third had suffered from bowel symptoms in the 6 months before taking the test. These unique characteristics of participants, which limit the generalizability of results to the wider population, may result from the programme's reliance on self-recruitment methods. Consistent evidence for improvements in mortality in populations screened for colorectal cancer is still required before a recommendation for widespread screening in Australia can be made.

Adult↗
PubMed1994

Effect of cerebrospinal fluid drainage and/or partial exsanguination on tolerance to prolonged aortic cross-clamping.

Paraplegia as a consequence of spinal cord ischemia associated with procedures on the thoracic and thoracoabdominal aorta has been linked to the interaction of proximal hypertension with elevated cerebrospinal fluid pressure (CSFP) during aortic cross-clamping (AXC). CSFP reduction via cerebrospinal fluid (CSF) drainage is thought to significantly prolong the cord's tolerance to AXC. Likewise, partial exsanguination is reported to effectively reduce ischemic injury by controlling proximal hypertension. To evaluate the individual and collective efficacy of both techniques, 18 mongrel dogs (25 to 35 kg), divided into three equal groups, underwent a fourth interspace left thoracotomy AXC. Baseline proximal arterial blood pressure (PABP), distal arterial blood pressure (DABP), and CSFP were established and monitored at 5-minute intervals during 120 minutes of AXC, and for 30 minutes thereafter. Group I animals were partially exsanguinated prior to AXC to maintain PABP at a mean of 115 to 120 mmHg. Group II animals had sufficient (16 +/- 5 cc) CSF withdrawn to maintain a DABP-CSFP gradient, i.e., spinal cord perfusion pressure (SCPP) of 20 mmHg. Group III animals were treated with both CSF drainage and partial exsanguination in the same manner as groups I and II, respectively. Perioperative somatosensory evoked potential (SEP) monitoring evaluated cord function. Postoperative neurological outcome was assessed with Tarlov's criteria. SEPs degenerated approximately 22 minutes following AXC for groups II and III. In contrast, group I exhibited rapid (10 +/- 7 min) SEP loss. All five surviving group I animals displayed paralysis 48 hours postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Reliability of assessing patellar alignment: the A angle.

Anterior knee pain syndrome is a complex problem for clinicians and patients. One possible etiological factor that has been identified is malalignment of the patella. Recently, a clinical method to assess patellar malalignment has been proposed--the A angle. However, no reliability of this technique was reported. Therefore, the purpose of this study was to determine intrarater and interrater reliability for the A angle. Thirty-six subjects participated in this study. Three raters measured each knee twice (N = 70). Interclass correlation coefficients (ICC) and standard error of measurements (SEM) were determined for the A angle and component measurements. Intrarater A-angle values ranged from 11.8 to 23.5 degrees. Intrarater A-angle ICCs were poor (0.20-0.32, SEM = 5.30-7.95 degrees). Interrater A-angle ICC was poor (-0.01, SEM = 7.82 degrees). Results indicated that the A angle as determined in this study was not reproducible. Therefore, further study is needed before the A angle can be used as a reliable assessment tool for patellar position.

Adult↗
PubMed1993

Molecular cloning and characterization of p64, a chloride channel protein from kidney microsomes.

Chloride channels were previously purified from bovine kidney cortex membranes using a drug affinity column. Reconstitution of the purified proteins into artificial liposomes and planar bilayers yielded chloride channels. A 64-kDa protein, p64, identified as a component of this chloride channel was used to generate antibodies which depleted solubilized kidney membranes of all chloride channel activity. This antibody has now been used to identify a clone, H2B, from a kidney cDNA library. Antibodies, affinity-purified against the fusion protein of H2B also depleted solubilized kidney cortex from all chloride channel activity. The predicted amino acid sequence of p64 shows that it contains two and possibly four putative transmembrane domains and potential phosphorylation sites by protein kinase A, protein kinase C, and casein kinase II. There was no significant homology to other protein (or DNA) sequences in the data base. The protein is expressed in all cells tested. Expression of its mRNA in Xenopus laevis oocytes led to the insertion of a protein with the appropriate molecular mass in microsomes but not in the plasma membrane. It is likely that p64 represents the chloride channel of intracellular organelles.

Amino Acid Sequence↗
PubMed1993

A comparison of tumor and normal tissue microvascular hematocrits and red cell fluxes in a rat window chamber model.

This laboratory has previously used a window chamber model to measure red blood cell velocity in mammary tumors and normal granulation tissues of the F-344 rat. Because red cell flux and hematocrit more accurately reflect the oxygen carrying potential of blood, we used this model to measure these parameters. Red blood cells were labelled with fluorescein isothiocyanate, and 0.2 ml. packed cells were injected intravenously into rats bearing an 8 to 10 day old R-3230 mammary carcinoma. beta-phycoerythrin (0.15 mg.) was also injected and served as a plasma dye to outline the blood vessels. A sample of peripheral blood was then taken and analyzed by flow cytometry to determine the labeled fraction of red blood cells. Flowing tumor and normal tissue vessels were recorded onto a VCR, and these video images were used to determine vascular length and diameter, RBC flux and velocity, and hematocrit. Median vessel diameter and loge (red blood cell flux) were significantly greater in tumors than in normal tissues (p = 0.007 and p < 0.025, respectively). After controlling for these variables, the median tumor hematocrit of 19% was not significantly greater than the median normal tissue hematocrit of 15%. This technique provides a nontoxic and reproducible method that is now being used to assist in the in vivo definition of tumor oxygenation.

Animals↗
PubMed1993

Auditory lexical decisions in children and adults: an examination of response factors.

This study examined the influence of nonlexical response factors on the speed of auditory lexical decisions in children and adults. Two groups of children (6- and 7-year-olds, 8- and 9-year-olds) and adults participated in three tasks: a real-word lexical decision task in which subjects were asked to say "yes" as quickly as possible to real words; a nonword lexical decision task in which subjects were asked to say "no" as quickly as possible to nonwords; and an auditory-vocal reaction time task in which subjects were asked to say "yes" or "no" to a tone. Response times on all tasks decreased with age. However, the age-related differences on the real-word lexical decision task disappeared when differences in auditory-vocal reaction times were taken into account. This result suggests that a large part of developmental differences in the speed of lexical processing may be due to nonlexical response factors.

Adult↗
PubMed1993

Effect of extradural analgesia on stress responses to abdominal surgery in infants.

We studied 40 children younger than 4 yr having elective abdominal surgery under general anaesthesia supplemented with either systemic opioids or extradural bupivacaine. Venous blood samples were obtained before tracheal intubation to measure baseline concentrations of adrenaline, noradrenaline, glucose, ACTH and cortisol. Additional samples were obtained 45 min after the start of surgery, at the end of surgery, 1 h and 24 h after the end of surgery. Plasma concentrations of bupivacaine were measured also in the extradural group at each sampling time. Both techniques provided acceptable analgesia, but the perioperative increases in adrenaline, glucose and ACTH were significantly greater in the opioid group. Noradrenaline concentrations decreased to less than baseline values in the extradural group and were significantly less than in the opioid group. The perioperative increase in cortisol was similar in the two groups, despite the differences in ACTH responses. Most responses returned to the baseline values within 24 h. Plasma bupivacaine concentrations remained within safe limits during the study, but systemic concentrations increased in some of the patients during postoperative infusion with 0.125% bupivacaine.

Abdomen↗
PubMed1993

Caregiver-infant interaction--comforting post-operative neonates.

Analysis of 40 h of videotaped caregiving to four male infants was conducted using ethology. All infants were full term and had major chest surgery 12 h previously. All incidents of caregiver-infant interaction were examined, and the verbal and tactile comforting behavior of the caregiver was coded for duration, context, infant cue and infant state prior and following the interaction. A total of 191 comforting incidents occurred during the study. Stroking was the most common form of touch used. Most of the comforting (60%) was given in the context of caregiving; sleeping infants were touched often (38%); 25.3% of the touches were given to acutely distressed infants, and wide awake infants relatively little. Most of the infants showed no change in infant state after the relatively brief comforting incidents, but in 15.7% of the incidents the infants 'settled' after comforting. The authors conclude that this is a relatively strong effect considering the short duration of the comforting actions.

Caregivers↗