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Biomedical subjects

J Willis

Publications and source records attributed to J Willis.

At least 19 recordsLinked to original sources
PubMed1992

Estrogen and progesterone receptor detection in archival formalin-fixed, paraffin-embedded tissue from breast carcinoma: a comparison of immunohistochemistry with the dextran-coated charcoal assay.

The steroid receptor (estrogen (ER) and progesterone receptor (PR] status was studied in 94 cases of invasive breast carcinoma from three separate institutions. All cases had fresh tissue examined for ER and PR by the dextran-coated charcoal cytosolic assay (DCC), and each case was examined immunohistochemically for ER and PR from archival formalin-fixed, paraffin-embedded tissue. Immunohistochemical assays (IH) were reviewed blinded to the DCC results and scored in a semiquantitative fashion prior to comparison to the DCC results. Overall, there was agreement between DCC and IH in 89% of ER and in 87% of PR assays. Some 50% of the ER discorrelations were of the IH-positive DCC-negative type, while 27% of the PR discorrelations were of this type. In four cases, both ER and PR did not correlate between IH and DCC determinations, with two being IH (ER and PR) positive and DCC negative, and two of the opposite type. The results of the study show that steroid receptor assays performed on routinely processed formalin-fixed archival material are reliable and closely recapitulate the results of traditional biochemical assays. Results suggest that, in the cases where IH is positive while DCC is negative, the IH result may actually provide a more reliable receptor status of the tumor than does the DCC result. Semiquantitation of fixed tissue IH assays shows a trend toward quantitative correlation with DCC results, but this correlation is weak, and factors concerning fixation and processing are most likely to be responsible.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1990

Cardiac microdialysis to estimate interstitial adenosine and coronary blood flow.

The purpose of this study was twofold: 1) to investigate the feasibility and usefulness of cardiac microdialysis for the simultaneous estimation of regional cardiac interstitial fluid (ISF) adenosine (ADO) concentration and coronary blood flow (CBF); and 2) to determine the changes in the ISF levels of ADO and CBF during cardiac stimulation or regional myocardial ischemia. Cardiac microdialysis probes were implanted in the left ventricular myocardium of chloralose-urethan-anesthetized dogs and perfused with Krebs-Henseleit buffer. The concentration of ADO in the effluent dialysate was used as an index of intramyocardial ISF ADO concentration while local CBF was measured by H2 clearance via a platinum wire within the dialysis fiber. Dialysate ADO was elevated immediately after insertion of the microdialysis probe, declined rapidly in the first 20 min, stabilized by 60 min, and remained constant for 2 h. Based on the relationship in vitro and in vivo between microdialysis probe perfusion rate and dialysate ADO concentration, ISF ADO concentration within the left ventricular myocardium was estimated to be 0.9-1.3 microM. Dobutamine (10 micrograms.kg-1.min-1) infusion resulted in a 36% increase in CBF and a 2.5-fold increase in dialysate ADO (n = 9; P less than 0.05). Regional myocardial ischemia, induced by occlusion of the left anterior descending artery (LAD), caused a 13-fold increase in dialysate ADO in the LAD perfused myocardium (n = 9; P less than 0.05). These results are consistent with the ADO hypothesis and suggest that cardiac microdialysis provides a reliable technique for the sampling of regional intramyocardial ISF.

Adenosine↗
PubMed1990

Asymmetries of sleep spindles and beta activity in pediatric EEG.

Unilateral suppression of beta activity, unilateral suppression of sleep spindles, and unilateral delta slowing on EEG have not been previously compared regarding accompanying neuroradiological (NR) and clinical neurological (CN) findings in children. We studied EEGs in children under age 10 years with unilateral beta suppression (n = 80), spindle suppression (n = 51) or unilateral delta slowing (n = 49). There were no significant differences between the three groups of abnormal EEGs in their relationships with NR and CN. Unilateral suppression of sleep spindles and beta activity are at least as accurate as focal slowing in lateralizing NR and CN findings.

Beta Rhythm↗
PubMed1990

Common pests.

Explore the source record for details and available documents.

Child↗
PubMed1990

Orbital anatomy for rehabilitation: the ocularist's point of view.

In the post enucleation and evisceration patient, we must continually seek to resolve the functional and cosmetic defects that occur following surgery. Fitting a prosthesis that appears to be symmetrical with the fellow eye is the measuring stick of our success. The success or failure in achieving this cosmetic symmetry will determine to a great degree the rehabilitation of the patient. It is important for the ocularist to have at least a basic understanding of the anatomic changes that have resulted in the anophthalmic socket to correctly assess and treat these changes. The authors suggest a method detailing the steps involved in making an accurate clinical assessment of the patient. The authors will also outline the defects normally associated with post enucleation syndrome, their usual causative effects, and provide a suggested reading list supplying information on both surgical and prosthetic correction for each of these areas.

Blepharoptosis↗
PubMed1989

Effect of pyruvate on regional ventricular function in normal and stunned myocardium.

The prolonged ventricular dysfunction following brief periods of coronary artery occlusion that does not produce irreversible damage has been termed the "stunned" myocardium. Although ventricular function returns to preischemic values by 1 to 7 days after reperfusion is established, inotropic therapy may be necessary to enhance contractility in the stunned heart. The purpose of this study was to determine the effect of pyruvate on ventricular function in normal and stunned myocardium. Eight chloralose/urethane anesthetized dogs were instrumented with ultrasonic crystals to measure systolic wall thickening in the left anterior descending artery (LAD) and left circumflex artery perfused regions of the left ventricle. Pyruvate (1 ml/min of 150 mM sodium pyruvate, pH 7.4) was infused directly into the LAD prior to and 30 minutes after a 10 minute LAD occlusion. Prior to LAD occlusion, LAD pyruvate infusion increased systolic wall thickening in the LAD-perfused region from 16.2% +/- 4.3% to 23.4% +/- 5.1% (p less than 0.05). Thirty minutes after LAD occlusion, regional wall thickening was depressed (3.3% +/- 2.6%; p less than 0.05), which is indicative of stunned myocardium. Subsequent LAD pyruvate infusion increased wall thickening in the stunned myocardium to 12.7% +/- 2.5%. The improvement of regional ventricular function was maintained only during the pyruvate infusion, as function returned to prepyruvate levels within 20 minutes after cessation of pyruvate infusion. These data indicate that pyruvate exerts a positive inotropic effect in normal and stunned myocardium. If pyruvate, a key intermediate in energy-producing pathways, exerts its inotropic effect through an enhancement of the energy state of the heart, it may have advantages over traditional inotropic agents in the treatment of postischemic contractile dysfunction.

Animals↗
PubMed1989

Somatosensory evoked potentials predict neuromotor outcome after periventricular hemorrhage.

Thirty-nine very low-birthweight (VLBW) preterm infants with periventricular hemorrhage (PVH) were studied with short-latency median nerve somatosensory evoked potentials (SEP) at two, four and/or six months corrected age, and subsequently were followed to a mean age of 22 months. All 12 infants with a single SEP showing unilateral absence or prolonged latency of the early cerebral (N1) response had motor abnormalities at follow-up. A single normal SEP predicted normal motor development in 19 of 36 infants; two normal SEPs did so in 15 of 26 infants, and three normal SEPs in 12 of 14 infants. These results demonstrate that SEPs play a useful rôle in predicting neuromotor outcome for VLBW preterm infants with PVH.

Cerebral Hemorrhage↗
PubMed1988

Cerebral involvement in children with acute and relapsing inflammatory polyneuropathy.

We present two children with seizures and other signs of cerebral involvement at the outset of acute inflammatory demyelinating polyneuropathy, consistent with a diagnosis of encephalomyeloradiculoneuropathy. One child had a recurrence associated with mild central dysfunction and improved during therapy with corticosteroids. Both children recovered completely. Both acute and relapsing inflammatory demyelinating neuropathy may be accompanied by cerebral dysfunction, expanding the clinical spectrum of encephalomyeloradiculoneuropathy.

Brain↗
PubMed1988

Stage II sleep alters infants' short latency somatosensory evoked potentials.

To evaluate the effects of stage II sleep on short latency somatosensory evoked potentials (SLSEP) to median nerve stimulation, we studied 16 normal infants from two to twelve months of age. SLSEP were recorded during waking and stage II sleep. Four channels of parasagittal EEG and behavioral observations were used to classify states. Compared with SEP in the waking state, cerebral potentials in stage II sleep were of much lower amplitude, even vanishing entirely in several infants. In addition, the change from waking to stage II sleep produced significantly longer latencies of the peaks N1, P1, and P2. We suggest performing SLSEP in infants in the waking state in order to assess cerebral somatosensory function.

Electrodes, Implanted↗
PubMed1988

Differential requirements for platelet aggregation and inhibition of adenylate cyclase by epinephrine. Studies of a familial platelet alpha 2-adrenergic receptor defect.

We describe a family whose members have impaired platelet aggregation and secretion responses to epinephrine with normal responses to adenosine diphosphate and collagen. Platelet alpha 2-adrenergic receptors (measured using 3H methyl-yohimbine) were diminished in the propositus (78 sites per platelet), his two sisters (70 and 27 sites per platelet), and parents (37 and 63 sites per platelet), but not in two maternal aunts (12 normal subjects, 214 +/- 18 sites per platelet; mean +/- SE). However, the inhibition of cyclic adenosine monophosphate (cAMP) levels by epinephrine in platelets exposed to 400 nmol/L PGI2 was similar in the patients and five normal subjects (epinephrine concentration for 50% inhibition, 0.04 +/- 0.01 mumol/L v 0.03 +/- 0.01 mumol/L; P greater than .05). In normal platelets, the concentration of yohimbine (0.18 mumol/L) required for half maximal inhibition of aggregation induced by 2 mumol/L epinephrine was lower than that for inhibition of its effect on adenylate cyclase (1.6 mumol/L). In quin2 loaded platelets, thrombin (0.1 U/mL) stimulated rise in cytoplasmic Ca2+ concentration, [Ca2+]i, was normal in the two patients studied. The PGI2 analog ZK 36,374 completely inhibited thrombin-induced rise in [Ca2+]i; the reversal of this inhibition by epinephrine was normal in the two patients. Thus, despite the impaired aggregation response to epinephrine, platelets from these patients have normal ability to inhibit PGI2-stimulated cAMP levels. These patients with an inherited receptor defect provide evidence that fewer platelet alpha 2-adrenergic receptors are required for epinephrine-induced inhibition of adenylate cyclase than for aggregation.

Adenosine Diphosphate↗
PubMed1987

Hypothalamo-pituitary-adrenal function in infantile spasms: effects of ACTH therapy.

The metyrapone test was used to study the hypothalamo-pituitary-adrenal function in ten children with infantile spasms, before and after ACTH treatment. The hypothalamo-pituitary-adrenal response was normal before ACTH treatment in almost all children. After ACTH, the responses of two children were suggestive of a diminished pituitary reserve; three were suggestive of decreased adrenal as well as decreased pituitary reserve, and one suggested either adrenal hyperplasia with normal pituitary reserve, or appropriate response to a developing medical stress. We suggest that, in children being treated with ACTH, the dosage of ACTH should be gradually tapered, AM cortisol levels should be monitored, and high-dose steroids should be included when treating medical stress.

Adrenocorticotropic Hormone↗
PubMed1986

Bringing the visiting diary up to date.

A method is described for the systematic assessment and review of long term dependent patients in a small practice using a personally developed computer program and assessment scale.

Aged↗
PubMed1986

Pharmacokinetics and sputum penetration of ciprofloxacin in patients with cystic fibrosis.

Levels of ciprofloxacin in serum and sputum were studied for eight patients with cystic fibrosis who were infected with Pseudomonas aeruginosa. Patients were studied in a steady state on a dosage of 500 mg every 8 h. Peak levels in serum ranged from 1.27 to 5.6 mg/liter (mean, 3.16 +/- 1.27), and absorption was rapid, the time to peak concentration ranging from 0.5 to 3.0 h (mean, 1.5 +/- 0.9). The antibiotic penetrated sputum well, achieving areas under the curve of approximately 46% of those obtained in serum.

Adolescent↗
PubMed1985

Inhibition of platelet function by contrast media: iopamidol and ioxaglate versus iothalamate. Work in progress.

The effects of an ionic contrast agent, meglumine iothalamate (Conray-60), and two newer low-osmolality radiographic contrast media, sodium meglumine ioxaglate (Hexabrix) and iopamidol (B-15,000), on platelet aggregation and secretion responses were studied. All three agents inhibited platelet responses during stimulation with adenosine diphosphate (ADP), epinephrine, and collagen. Platelet function was inhibited by iothalamate at concentrations of 11 mg iodine/ml and above, and by the newer agents at concentrations above 30 mg iodine/ml. Addition of exogenous calcium decreased the iothalamate-induced inhibition of aggregation but did not improve dense granule secretion. There was no consistent effect of exogenous calcium on platelet inhibition by iopamidol and ioxaglate. These studies indicate that the newer agents inhibit platelet function less than iothalamate does, and that chelation of Ca2+ may not be the major mechanism of platelet inhibition by contrast agents.

Blood Platelets↗