Biomedical subjects

C Smith

Publications and source records attributed to C Smith.

At least 667 records · Page 37Linked to original sources

PubMed1991

An estrogen-responsive element mediates the transcriptional regulation of calbindin D-9K gene in rat uterus.

The rat calbindin (molecular mass 9 kDa) gene sequence revealed the presence of an imperfect palindromic estrogen-responsive-like element (ERE) located at position +51 from the transcriptional initiation site. This element has the sequence AGGTCAGGGTGATCT which differs by one nucleotide from the vitellogenin ERE palindromic sequence AGGTCACTGTGACCT. The activity of this element to induce transcription in response to estrogen and the ability to bind estrogen receptor was investigated. This sequence confers estrogen-dependent transcriptional activity when cloned upstream from the tkp-CAT construct in pBLCAT2 plasmid and transfected into T47D cells, similar to the vitellogenin gene ERE activity but to a lesser extent. This element binds to the estrogen receptor in vitro as assessed by gel retardation assay similar to the vitellogenin gene ERE. No such binding was detected when a mutant sequence AGATCACTGTGATCT was used. The specificity of the complex was confirmed using polyclonal antibodies, ER712 raised against the estrogen receptor. Furthermore, competition assays showed that both sequences were able to compete for binding to the estrogen receptor. The in vivo transcriptional regulation of the calbindin D-9K gene by estrogen was also investigated in the rat. Female animals maintained on a vitamin D-sufficient or a vitamin D-deficient diet were ovariectomized, housed for 3 weeks, and then injected with 17 beta-estradiol (0.5 micrograms/kg body weight/day). Slot blot analysis of total RNA showed a marked increased in calbindin D-9K mRNA levels in the uterus but not in the intestine by 26 and 50 h post-injection. These results demonstrate that the calbindin D-9K gene is transcriptionally regulated by estrogen in the uterus mediated by an estrogen-responsive element identified in the gene.

Animals↗

PubMed1991

Single laser three color immunofluorescence staining procedures based on energy transfer between phycoerythrin and cyanine 5.

Monoclonal antibodies specific for phycoerythrin (PE) were covalently labeled with the fluorescent dye cyanine 5 (Cy5). Excitation at 488 nm of immune complexes obtained by mixing Cy5-anti-PE with PE resulted in a 4-fold reduction of PE fluorescence measured at 565 nm and an increase of fluorescence measured at 655 nm. The observed energy transfer between PE and Cy5-anti-PE was used to develop three color immunofluorescence staining procedures for flow cytometers equipped with an Argon laser tuned at 488 nm. Mouse IgG1 monoclonal antibodies specific for cell surface antigens were cross-linked with either unlabeled or Cy5 labeled mouse IgG1 anti-PE using F(ab')2 fragments of monoclonal rat anti-mouse IgG1. PE was added to these immune complexes in sufficient amounts to saturate all PE binding sites. Cells were incubated with PE-labeled and PE/Cy5-labeled tetrameric antibody complexes together with FITC labeled antibodies and analyzed by flow cytometry. The emission from FITC, PE and PE/Cy5 could be readily separated and bright three color immunofluorescence staining of mononuclear cells from human peripheral blood and bone marrow was observed. The results of these experiments demonstrate that useful probes for single laser three color staining of cell surface antigens can be readily obtained by mixing of selected reagents. Compared to standard procedures for the covalent labeling of PE (tandem) molecules to antibodies, the non-covalent procedures described in this report provide significant advantages in terms of the amount of reagents, time and equipment required to obtain suitable reagents for three color immunofluorescence staining.

Animals↗

PubMed1991

Laser-induced fluorescence emission: I. The spectroscopic identification of fibrotic endocardium and myocardium.

UNLABELLED: Laser-induced fluorescence has been developed as a guidance system for laser angioplasty. Laser ablation has been used for resection of arrhythmogenic ventricular scar. We have investigated the use of laser-induced fluorescence for the detection of fibrotic and ischemic changes in endocardium and myocardium. Fluorescence emission spectra from human necropsy specimens were correlated with histologic examination. Normalized fluorescence intensity detected from both the endocardial and the myocardial surfaces of the fibrotic ventricular specimens was significantly higher than that of corresponding normal specimens at 440 to 475 nm. Fibrotic endocardium could be identified by a fluorescence emission intensity ratio less than 1.5 for wavelength ratio 375/450nm. Acutely infarcted endocardium was recognizable by a ratio of 1.5 to 2.0. The specificity and sensitivity of detection of scarred endocardium was 70 and 100%, respectively. Fibrotic myocardium was also consistently identified by fluorescence spectroscopy. CONCLUSION: Fluorescence emission spectroscopy can differentiate normal and fibrotic endocardium and myocardium, in vitro. This technique may be useful for guidance during laser ablation of arrhythmogenic ventricular scar.

Capillaries↗

PubMed1991

Analysis of DNA restriction fragments greater than 5.7 Mb in size from the centromeric region of human chromosomes.

Pulsed electrophoresis was used to study the organization of the human centromeric region. Genomic DNA was digested with rare-cutting enzymes. DNA fragments from 0.2 to greater than 5.7 Mb were separated by electrophoresis and hybridized with alphoid and simple DNA repeats. Rare-cutting enzymes (Mlu I, Nar I, Not I, Nru I, Sal I, Sfi I, Sst II) demonstrated fewer restriction sites at centromeric regions than elsewhere in the genome. The enzyme Not I had the fewest restriction sites at centromeric regions. As much as 70% of these sequences from the centromeric region are present in Not I DNA fragments greater than 5.7 and estimated to be as large as 10 Mb in size. Other repetitive sequences such as short interspersed repeated segments (SINEs), long interspersed repeated segments (LINEs), ribosomal DNA, and mini-satellite DNA that are not enriched at the centromeric region, are not enriched in Not I fragments of greater than 5.7 Mb in size.

Centromere↗

PubMed1991

The early care and feeding of anorexics.

Comparing mothers' reports of early feeding practices in 18 mothers of anorexics and 25 mothers of normal children by means of a questionnaire, we found that the mothers of anorexics introduced solids earlier and used Schedule rather than Demand feedings more frequently. The mothers of anorexics did not treat patients and control siblings differentially. Our study suggests that differences in early feeding and in infant temperament may be operative in the pathogenesis of anorexia nervosa.

Adolescent↗

PubMed1991

Site-specific mutagenesis of annexin V: role of residues from Arg-200 to Lys-207 in phospholipid binding.

Annexin V (placental anticoagulant protein I) binds tightly to anionic phospholipid vesicles in the presence of calcium. Four mutant proteins were expressed in Escherichia coli in which Ala replaced one of the following residues in the third repeat of annexin V: Arg-200, His-204, Arg-206, or Lys-207. In a competitive fluorescence quenching assay, the wild-type recombinant protein had the same affinity for phosphatidylserine-containing vesicles as the placentally derived protein. The affinity of the four mutant proteins for phosphatidylserine-containing vesicles was unchanged relative to wild-type protein. We conclude that His-204 and adjacent basic residues, including the highly conserved Arg-200 residue, are not required for high-affinity phospholipid binding.

Amino Acid Sequence↗

PubMed1991

The antioxidant action of ketoconazole and related azoles: comparison with tamoxifen and cholesterol.

The azole antifungal drug ketoconazole was found to inhibit Fe(III)-ascorbate dependent lipid peroxidation using either rat liver microsomes or ox-brain phospholipid liposomes as the substrate. It also inhibited microsomal peroxidation induced by the Fe(III)-ADP/NADPH system. The related azoles, miconazole and clotrimazole, were much weaker inhibitors than ketoconazole. Ketoconazole was approximately equipotent with the triphenylethylene anticancer drug tamoxifen in the microsomal system and was almost as effective as 4-hydroxytamoxifen in the liposomal system. Ketoconazole introduced into phospholipid liposomes during their preparation inhibited Fe(III)-ascorbate induced lipid peroxidation to a greater extent than similarly introduced cholesterol, ergosterol or tamoxifen. Miconazole and clotrimazole were again poor inhibitors of lipid peroxidation in this system. These antioxidant effects of ketoconazole may be due to membrane stabilization in the systems used. The implications of our findings for the clinical applications of these drugs are discussed.

Animals↗

PubMed1991

Successful tracheal autotransplantation with a vascularized omental flap.

A major problem in tracheal transplantation is the restoration of an adequate vascular supply to the transplanted trachea. In 12 piglets, a segment (6 rings) of thoracic trachea was removed and the excised segment was then sutured back in place. In 9 animals (group A), a vascularized omental flap was wrapped around the autotransplanted trachea. In the other 3 pigs (group B), the omentum was not used. Eight of 9 group A pigs were killed, 1 or 2 months later, having had no signs of airway obstruction; the 9th pig was killed after 14 days because of airway obstruction. The 3 pigs in group B were killed after 11 to 13 days because of progressive respiratory obstruction. In the 8 asymptomatic pigs in group A, the omental flap was viable and tracheal growth was normal with no differences in diameter between normal and autotransplanted trachea. Histologically intact cartilage was lined with respiratory epithelium. In the one group A pig who was killed early, the omental flap was necrotic. In this pig and in the 3 group B animals, extensive tracheal necrosis and nonviable cartilage were observed. These findings indicate that in the pig, a 6-ring segment of trachea can be transplanted with vascularization provided by an omental flap.

Animals↗

PubMed1991

Respiratory failure due to retained esophagus: a complication of esophageal replacement.

Recurrent fistulas occur in about 10% of infants treated for esophageal atresia with distal tracheoesophageal fistula. Failed repair of a recurrent fistula rarely requires esophageal replacement and removal or diversion of the native esophagus. We present a patient who underwent multiple operations for recurrent tracheosophageal fistula whose native esophagus was eventually replaced with a colonic interposition graft. Over the subsequent 9 years he experienced failure to thrive, respiratory distress, and repeated pulmonary infections attributed to chronic aspiration. Eventually, he developed respiratory failure and required endotracheal intubation and mechanical ventilation. He became increasingly difficult to ventilate and, in spite of aggressive efforts, suffered a cardiac arrest from which he could not be resuscitated. At postmortem, a dilated blind segment of native esophagus, which was compressing and obstructing the malacic trachea, was found in the posterior mediastinum. Death was caused by massive air embolus, which was in turn attributed to the high airway pressures needed to ventilate the patient. Tracheal compression by a remnant of native esophagus should be considered in the differential diagnosis of respiratory failure after esophageal replacement.

Child↗

PubMed1991

Pharmacokinetics of peptide T in patients with acquired immunodeficiency syndrome (AIDS).

1. The pharmacokinetics of Dala1-peptide T-NH2 (peptide T) was determined during phase I clinical trials in patients with acquired immunodeficiency disease (AIDS) and AIDS related complex (ARC). Drug levels were determined by specific RIA, and in some cases with HPLC analysis, after intravenous (i.v.) or intranasal (i.n.), via metered sprayer, administration. 2. The plasma kinetics appeared to be bi-phasic with a first compartment half-life of 30 to 60 minutes and a second plasma clearance rate of 4 to 6 hours, observed for both routes of administration. Peptide T, in one individual was confirmed to be present at 6 hrs in plasma, determined after HPLC isolation followed by specific RIA. 3. Bioavailability, determined for a 2 mg test dose in six individuals was 9.3 +/- 6.9 nmol/L. Peak plasma levels of 41 +/- 30 nmol/L after 10 mg i.n., 2.8 +/- 5.9 nmol/L after 2 mg i.n., and 0.13 +/- 0.07 nmol/L after 0.4 mg i.n. were observed. In two individuals tested, peptide T was detected in CSF at levels 20% of the corresponding plasma level 90 and 145 minutes post i.v. administration. Peptide T was not detected in urine. I.N. administration was well tolerated for times up to 21 months.

Acquired Immunodeficiency Syndrome↗

PubMed1991

Paradoxical sleep increases predict successful learning in a complex operant task.

The sleep of 16 Sprague-Dawley rats was continuously monitored both before and during task acquisition. Eight rats were exposed in turn to autoshaping, 10-response fixed-ratio (FR 10), and sequential operant (SO) tasks. They all learned the autoshaping and FR 10 tasks with equal ease. However, 4 rats were unable to solve the SO task and were labeled as slow learning (SL). The other 4 rats did learn the task and were labeled as fast learning (FL). FL rats exhibited more paradoxical sleep than either the SL group or the two control groups. The results suggest a subtle, but as yet unknown, biological difference between FL and SL rats within the Sprague-Dawley strain.

Animals↗

PubMed1991

Some biochemical and behavioural aspects of the paradoxical sleep window.

It has recently been proposed that there is a vulnerable period of time following successful learning when paradoxical sleep (PS) is necessary for learning. This vulnerable time period has been called the PS window. In Experiment 1, the protein synthesis inhibitor anisomycin (ANI) was administered following shuttle avoidance training in the Sprauge-Dawley rat to coincide with the onset of an established PS window. Control groups received either saline or ANI either 3 hours before or 3 hours after the beginning of the PS window. Three hours after the injection, each group was retested. Then animals were immediately sacrificed, and whole brain biochemical analyses were done on levels of acetylcholine (ACh) and activity of acetylcholinesterase (AChE). Only the rats given ANI timed to coincide with the beginning of the PS window showed learning deficits. All ANI-treated groups had less ACh and AChE activity. In Experiment 2, the ACh antagonist scopolamine (SCOP) was injected at the same times as in Experiment 1, and each of these groups had a corresponding saline control group as before. Retesting was done 1 day later; once again, the only group to show learning deficits was the group receiving SCOP timed to coincide with the PS window. Results suggested that the transmitter ACh plays an important role in learning/memory processes at the PS window.

Acetylcholine↗

PubMed1991

Mental function after general anaesthesia for transurethral procedures.

We have assessed the influence of age and preoperative mental status score on postoperative mental function, using a choice reaction time test. One hundred and twelve patients (mean age 70 yr, range 48-88 yr) were given a standardized general anaesthetic for transurethral procedures. Mental status before anaesthesia was measured with the Clifton Assessment Procedure for the Elderly (CAPE). Reaction time was measured before anaesthesia and for up to 3 days after anaesthesia. Variability in reaction time performance was increased 24 h after anaesthesia in transurethral patients, but not in a control group of orthopaedic patients (P = 0.0006). Factors contributing to increased variability of reaction time after operation in a multiple regression analysis were reduced CAPE score before operation (P less than 0.0001), extent of surgery (P = 0.023), postoperative pain (P = 0.007) and postoperative sedative drugs (P = 0.009). Factors not contributing included age, diagnosis of cancer, number of previous operations in past 5 years, duration of anaesthesia, minimum mean arterial pressure, minimum and maximum perioperative PCO2 values, postoperative pyrexia and poor sleep.

Aged↗

PubMed1991

"Pssst . . . the really useful guide to alcohol": evaluation of an alcohol education television series.

The paper reports on the effectiveness of a six-part television series ("Pssst . . . the really useful guide to alcohol") in changing viewers' knowledge and alcohol-related behaviours and attitudes. Comparisons between viewers and matched controls indicated significant increases in knowledge relating to alcohol. No changes in attitudes were found, although some behavioural change was indicated. These results are discussed in the context of wider-ranging alcohol-related health promotion initiatives.

Adolescent↗

PubMed1991

Patterns of drinking in Wales.

As part of a larger survey of health-related behaviours, 8441 Welsh men and women aged 18-64 years provided information relating to their overall consumption of alcohol, frequency of binge drinking (defined as consumption of at least half the recommended weekly limits, less than or equal to 21 units for men, less than or equal to 14 units for women) per occasion, and changes in consumption over time. Key findings indicate 29% of men and 9% of women report drinking in excess of the recommended safe limits, whilst 28% and 8% respectively report binge drinking at least once weekly. Such drinking is not, however, confined to heavy drinkers: 14% of men and 5% of women who drink within the recommended safe limits also report binge drinking at least once weekly. These and other results are discussed in relation to future health promotion initiatives.

Adolescent↗

PubMed1991

Increases in number of REMS and REM density in humans following an intensive learning period.

Animal studies have recently demonstrated that increases in rapid eye movement (REM) sleep and actual number of rapid eye movements (REMs) over normal levels followed successful learning of an avoidance task. These increases persisted for many days following the end of the training sessions. It was hypothesized that similar extended increases in REM sleep parameters would follow an intensive learning task in humans. Senior college students were sleep monitored following the end of their Christmas examinations. Results showed that there was a significant increase in the number of REMs observed following the exams as compared to baseline and control subject values. The number of extra REMs was mot prominent during the fifth REM period of the night. A significantly increased REM density was observed at the fourth REM sleep period of the night. Results support the idea of REM sleep and/or the REMs themselves being involved in long-term memory processing several days after the end of training.

Achievement↗

PubMed1991

Marked plasmacytosis and immunoglobulin abnormalities following infusion of streptokinase.

Marked plasmacytosis is an uncommon clinical finding associated with plasma cell dyscrasias and certain reactive states, particularly serum sickness. Moreover, serum sickness-like reactions are a well-recognized complication of therapy with streptokinase. In this report, the authors describe a patient who developed a transient, but striking, plasmacytosis and an unexplained fever following streptokinase treatment for a pulmonary embolus. An evaluation for multiple myeloma was completely negative except for the occurrence of serum monoclonal-like proteins which largely disappeared over an eight month period.

Humans↗

PubMed1991

Immunomodulation of kidney and heart transplants by anti-idiotypic antibodies.

To explore the possibility that circulating HLA antigens from the graft and anti-anti-HLA (anti-idiotypic) antibodies influence the long-term survival of renal and cardiac allografts, analysis of 330 renal allograft recipients and 174 recipients of cardiac allografts was conducted. Anti-donor-HLA antibodies (Ab1) present before or after transplantation are associated with graft failure, whereas irrelevant anti-HLA antibodies had no impact on actuarial graft survival. Ab1 may be uncovered by dissociation of immune complexes and depletion of soluble antigens with monoclonal antibody-coated magnetic beads. Of the 421 sera tested from 65 heart recipients, 97 showed Ab1 before depletion and 178 after depletion; similar rise in positive sera was seen in 39 renal transplant recipients. Three distinct patterns of appearance of Ab1 and Ab2 (anti-Ab1 antibody) were recognized. Patients with cyclic variations of Ab1 in association with Ab2 had 100% graft survival, whereas patients with cyclic variations of Ab1 but no detectable Ab2 had 2-year graft survival of 36% for kidneys and 71% for hearts. Presence of Ab1 in all sera after transplantation led to 47% and 56% 2-year renal and heart allograft survival, respectively.

Actuarial Analysis↗