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Biomedical subjects

A Lee

Publications and source records attributed to A Lee.

At least 487 records · Page 27Linked to original sources
PubMed1994

Homogeneous fluorescence detection method for human leukocyte antigen-DR typing following polymerase chain reaction amplification with sequence-specific primer.

A fluorescent homogeneous method for the detection of sequence-specific amplification of human leukocyte antigen (HLA) alleles has been developed. In this approach, polymerase chain reaction sequence-specific primers (PCR-SSP) are used to amplify DRB1, DRB3, and DRB4 alleles. Lambda exonuclease and Exonuclease I are added to reduce background by digesting template DNA, partial primer dimer, and primer. PCR amplicons are then detected following the addition of a fluorescent dye (thiazole yellow dimer) which binds to double-stranded DNA. No transfer or wash steps are required. Thus, the risk of sample contamination, which is a major source of inaccuracy for DNA amplification methods, is greatly reduced. This approach is also faster and more easily automated than the standard approach using gel electrophoresis and ethidium bromide staining. Speed and automation are important considerations for HLA typing since the number of possible alleles for each HLA type is substantial. A homogeneous HLA-SSP typing method may be especially useful for clinical labs doing large numbers of samples and for the eventual automation of HLA DNA typing.

Alleles↗
PubMed1994

Intra-abdominal pressure measurement using a modified nasogastric tube: description and validation of a new technique.

OBJECTIVE: This study assessed the accuracy of an intragastric method of measuring intra-abdominal pressure (IAP). DESIGN: Prospective sequential study with simultaneous paired measurement of gastric and urinary bladder pressures. SETTING: Operating theatre, University Teaching Hospital. PATIENTS: 9 patients undergoing laparoscopic cholecystectomy were studied. INTERVENTIONS: Intraperitoneal pressures were monitored during peritoneal insufflation at laparoscopy up to a pressure of 20 mmHg. MEASUREMENTS AND RESULTS: Intra-abdominal pressure measurements were recorded simultaneously using a gastric balloon and urinary catheter. Gastric pressure may be up to 4 mmHg higher or 3 mmHg lower than urinary bladder pressure. CONCLUSIONS: Intra-abdominal pressure can be measured easily in this new fashion, allowing a continuous pressure trend to be obtained without interfering with urinary output estimation.

Abdomen↗
PubMed1994

I, you, me, and autism: an experimental study.

The nature of autistic individuals' abnormalities in the use of personal pronouns has been a topic of considerable speculation but little systematic investigation. We tested groups of CA- and verbal MA-matched autistic and nonautistic mentally retarded children and young adults on a series of tasks that involved the comprehension and use of the personal pronouns "I," "you," and "me." All subjects were able to comprehend these pronouns within the test situations, and there were few instances of pronoun reversal. However, autistic subjects were significantly less likely to employ the pronoun "me" in a visual perspective-taking task (when instead they tended to say: 'I can see the . . .'), and lower ability subjects were more likely to use their own proper names rather than personal pronouns in certain photograph-naming tasks. There were also circumstances in which autistic subjects were less likely than controls to employ the pronoun "you" to refer to the experimenter. A high proportion of these autistic subjects were reported to have current difficulties with personal pronouns in their everyday life, and we discuss some alternative interpretations of the results.

Adolescent↗
PubMed1994

Polyunsaturated fatty acids modulate stomatal aperture and two distinct K+ channel currents in guard cells.

Regulation of stomatal aperture is critical for both CO2 uptake and water retention by plants. Stomatal opening is produced by osmotic water flow into guard cells, which follows K+ transport across the plasma membrane. We report here that linolenic acid and arachidonic acid, but not several other fatty acids, enhance stomatal opening and inhibit stomatal closing. In patch clamped guard cell protoplasts, linolenic and arachidonic acid rapidly potentiated inward K+ currents and inhibited outward K+ currents, which are carried via distinct K+ channels. These results suggest that certain fatty acids regulate stomatal aperture by modulation of two different K+ channels and may act as second messengers for stimuli that regulate CO2 uptake and water retention by plants.

Carbon Dioxide↗
PubMed1994

Do nurses know when to summon emergency assistance?

At Liverpool Hospital in 1989, mortality from cardiopulmonary arrest was 71% in the general wards, and 64% in the Emergency department. In an attempt to identify and treat seriously ill patients before they progressed to cardiac arrest, a medical emergency team (MET) was established. The MET replaced the existing cardiac arrest team and comprised a nurse from the intensive care unit (ICU), a resuscitation registrar (an anaesthetics trainee), a medical registrar and a senior registrar from the ICU. The resuscitation registrar was the team leader. The calling criteria for the MET were based on predetermined physiological variables, abnormal laboratory results, and specific conditions or if nursing or medical staff were concerned by the patient's condition. A study was conducted 2 years following implementation of the MET system, to determine registered nurses' (RNs) opinions, knowledge and use of the system. A questionnaire distributed to 141 nurses rostered on the chosen study date revealed a positive attitude the MET, although there was a low awareness regarding the availability of the MET information booklet. 53% of nurses had called the MET in the last 3 months; all would call the team again in the same circumstances. The correct response in three of four hypothetical situations presented was to call the MET. The number of correct responses varied between scenarios from 17-73%. Hypotension did not appear to alert nurses to summon emergency assistance. Some nurses, despite the presence of severe deterioration and patient distress, called the resident rather than the MET.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

"Voluvision": three-dimensional ultrasonography of fetal malformations.

OBJECTIVE: A new technique using three-dimensional ultrasonography and its performance in fetal malformations imaging was evaluated. STUDY DESIGN: A case of fetal complex malformation with bipartite scrotum combined with hypospadias and duodenal atresia is reported. RESULTS AND CONCLUSION: Three-dimensional ultrasonography provides important additional information in diagnosing fetal malformations.

Abnormalities, Multiple↗
PubMed1994

LSD flashback syndrome exacerbated by selective serotonin reuptake inhibitor antidepressants in adolescents.

Two adolescents with a long history of abuse of lysergic acid diethylamide (LSD) and symptoms consistent with major depressive disorder, on initiation of antidepressant therapy with selective serotonin reuptake inhibitor agents, had the new onset or worsening of LSD flashback syndrome. The similarity in neuroreceptor physiology for both LSD and serotonin suggests that the LSD flashback syndrome may be induced by these drugs in patients with a history of LSD abuse.

1-Naphthylamine↗
PubMed1994

The basic knowledge assessment tool: is it useful?

Registered Nurses (RN's) caring for the critically ill, require a wide range of specialised skills and knowledge. Assessing knowledge of RN's within Intensive Care Units (ICU's) is imperative if we are to ensure that patients are afforded quality care. The aim of this study was to evaluate existing knowledge of the RN's working in the ICU of a major teaching hospital using the Basic Knowledge Assessment Tool (BKAT). Overall mean test scores of 78% were encouraging. Knowledge gaps were evident in gastrointestinal and endocrine disorders. Significantly higher scores were obtained by RN's trained in the hospital based system (p = 0.02) and those possessing ICU qualifications (p = 0.01). There were no differences in scores according to age and length of ICU experience. Registered nurses scored badly in a number of questions, which highlighted some problems in the terminology used in the BKAT.

Adult↗
PubMed1994

Breath hydrogen after ingestion of the bulk sweeteners sorbitol, isomalt and sucrose in chocolate.

The effect of eating chocolate containing sugar alcohols as sweetening agents on colonic fermentation has been investigated by monitoring breath H2 levels. Levels were compared with those occurring after the consumption of normal, sugar-containing chocolate. Ten healthy volunteers aged 19 to 21 years ingested equal amounts of either sorbitol, isomalt or sucrose incorporated into standard chocolate bars. Breath H2 levels after consumption of chocolate containing either sorbitol or isomalt were significantly higher than those after consumption of chocolate containing sucrose (P < 0.001). After consumption of chocolate containing sorbitol, double the mean estimated volume of breath H2 was produced over 6 h compared with that produced after eating chocolate containing isomalt. Taken together with results relating to the incidence of intolerance symptoms, these findings demonstrate that sorbitol is associated with greater colonic fermentation compared with isomalt.

Adult↗
PubMed1994

Cognitive deficits and personality patterns in maternally versus paternally inherited myotonic dystrophy.

Neuropsychological functioning was compared between 7 myotonic dystrophy (MD) patients with maternal inheritance (mMD), 14 MD patients with paternal (pMD) inheritance, and 10 normal controls. Both groups evidenced slowed performance on a measure of information processing speed. However, the pMD group had an otherwise normal neuropsychological profile. In contrast, the mMD group exhibited abnormal scores on measures of intelligence, visual-construction, and some, albeit not all, measures of frontal functioning. No significant differences between the three groups were detected on measures of verbal or visual memory, or on measures of visual-perception. Overall, these findings suggest that inheritance pattern is one important moderating variable in determining the impact of the MD gene on cognitive functioning. Personality assessment revealed a relatively high incidence of dependent tendencies and depressive symptoms, even among pMDs. Given the generally normal cognitive functioning among pMDs, personality/emotional disturbance observed among MD patients may largely reflect their adjustment to having a progressively disabling medical condition, rather than being a direct expression of MD related brain dysfunction.

Adult↗
PubMed1994

Recombinant Vgr-1/BMP-6-expressing tumors induce fibrosis and endochondral bone formation in vivo.

Members of the TGF-beta superfamily appear to modulate mesenchymal differentiation, including the processes of cartilage and bone formation. Nothing is yet known about the function of the TGF-beta-related factor vgr-1, also called bone morphogenetic protein-6 (BMP-6), and only limited studies have been conducted on the most closely related factors BMP-5, osteogenic protein-1 (OP-1) or BMP-7, and OP-2. Because vgr-1 mRNA has been localized in hypertrophic cartilage, this factor may play a vital role in endochondral bone formation. We developed antibodies to vgr-1, and documented that vgr-1 protein was expressed in hypertrophic cartilage of mice. To further characterize the role of this protein in bone differentiation, we generated CHO cells that overexpressed recombinant murine vgr-1 protein. Western blot analysis documented that recombinant vgr-1 protein was secreted into the media and was proteolytically processed to yield the mature vgr-1 molecule. To assess the biological activity of recombinant vgr-1 in vivo, we introduced the vgr-1-expressing CHO cells directly into the subcutaneous tissue of athymic nude mice. CHO-vgr-1 cells produced localized tumors, and the continuous secretion of vgr-1 resulted in tumors with a strikingly different gross and histological appearance as compared to the parental CHO cells. The tumors of control CHO cells were hemorrhagic, necrotic, and friable, whereas the CHO-vgr-1 tumors were dense, firm, and fibrotic. In contrast with control CHO tumors, the nests of CHO-vgr-1 tumor cells were surrounded by extensive connective tissue, which contained large regions of cartilage and bone. Further analysis indicated that secretion of vgr-1 from the transfected CHO tumor cells induced the surrounding host mesenchymal cells to develop along the endochondral bone pathway. These findings suggest that endochondral bone formation.

Amino Acid Sequence↗
PubMed1994

The chromosome end in yeast: its mosaic nature and influence on recombinational dynamics.

Yeast chromosome ends are composed of several different repeated elements. Among six clones of chromosome ends from two strains of Saccharomyces cerevisiae, at least seven different repeated sequence families were found. These included the previously identified Y' and X elements. Some families are highly variable in copy number and location between strains of S. cerevisiae, while other elements appear constant in copy number and location. Three repeated sequence elements are specific to S. cerevisiae and are not found in its evolutionarily close relative, Saccharomyces paradoxus. Two other repeated sequences are found in both S. cerevisiae and S. paradoxus. None of those described here is found (by low stringency DNA hybridization) in the next closest species, Saccharomyces bayanus. The loosely characterized X element is now more precisely defined. X is a composite of at least four small (ca. 45-140 bp) sequences found at some, but not all, ends. There is also a potential "core" X element of approximately 560 bp which may be found at all ends. Distal to X, only one of six clones had (TG1-3)n telomere sequence at the junction between X and Y'. The presence of these internal (TG1-3)n sequences correlates with the ability of a single Y' to expand into a tandem array of Y's by unequal sister chromatid exchange. The presence of shared repeated elements proximal to the X region can override the strong preference of Y's to recombine ectopically with other Y's of the same size class. The chromosome ends in yeast are evolutionarily dynamic in terms of subtelomeric repeat structure and variability.

Base Sequence↗
PubMed1994

Hepatitis A and evidence against the community dissemination of Helicobacter pylori via feces.

Seroprevalence data from 1501 subjects was used to test the hypothesis that Helicobacter pylori may be transmitted by the fecal-oral route. Antibody to hepatitis A virus was used as a marker of fecal-oral exposure. Of the 1501 subjects, 35.5% were seropositive for both H. pylori and hepatitis A, 19.1% were seronegative for both, 36.5% were seropositive for hepatitis A only, and 8.8% were seropositive for H. pylori only. Cross-sectional data from rural areas supported an association between hepatitis A and H. pylori. However, in the urban area there was no evidence of hepatitis A infection in persons < 10 years old, yet the seroprevalence of H. pylori was high in this group (approximately 32%). From our data, we suggest that communitywide fecal-oral spread of H. pylori may be of limited importance.

Adolescent↗
PubMed1994

Clinical signs and symptoms in pulmonary embolism. A reassessment.

The clinical diagnosis of pulmonary embolism (PE) remains difficult despite years of investigation. The clinical signs and symptoms of pulmonary embolism are numerous, but they are not diagnostically accurate. Radionuclide ventilation perfusion imaging (VQ) has become an important adjunct in screening patients for suspected PE. This study re-evaluates the predictive capabilities of various clinical signs and symptoms in a population of patients in whom angiography was thought to be necessary because of clinical concern for PE. One hundred one patients with suspected PE were retrospectively identified. Clinical information on them was complete, and laboratory studies, VQ imaging, and pulmonary angiography were performed. Thirty-seven clinical signs, symptoms, and other characteristics were individually compared for patients whose angiographic results were positive or negative for PE. Modifying or interactive effects on PE were then examined with logistic regression analysis. Several clinical conditions, including immobilization and recent surgery, were significantly associated with PE. Shortness of breath and history of smoking were significantly associated with negative results on pulmonary angiography. A "high probability" VQ scan was highly predictive (P < .0001) of positive results on angiography. When interactive factors for PE were examined, lack of shortness of breath and arterial pH < or = 7.45, lack of shortness of breath and respiratory rate > 23, diaphoresis in a nonsmoker and immobilized female, were significantly associated with PE. This study again documents the difficulty in using clinical criteria--including signs, symptoms, and laboratory determinations--to predict PE accurately, even in a population in which PE was of clinical concern irrespective of the VQ scan results.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1994

Rapid RT-PCR amplification from limited cell numbers.

We describe a rapid and efficient RT-PCR method particularly suited to procedures involving limited cell and target gene copy numbers. Purified leukocytes and myeloid colonies derived from patients with chronic myelogenous leukemia (CML) in chronic phase were used for direct RT-PCR. Purified cells and colonies were lysed using a small quantity of DEPC-treated water containing RNasin as an RNA inhibitor. The untreated lysate was either used immediately for RT-PCR or frozen at -70 degrees C for later use. By this method we were able to consistently amplify bcr-abl transcripts from as few as 10 cells. No noticeable difference was observed between products amplified from fresh and frozen samples.

Base Sequence↗
PubMed1994

Arabidopsis COP8, COP10, and COP11 genes are involved in repression of photomorphogenic development in darkness.

Wild-type Arabidopsis seedlings are capable of following two developmental programs: photomorphogenesis in the light and skotomorphogenesis in darkness. Screening of Arabidopsis mutants for constitutive photomorphogenic development in darkness resulted in the identification of three new loci designated COP8, COP10, and COP11. Detailed examination of the temporal morphological and cellular differentiation patterns of wild-type and mutant seedlings revealed that in darkness, seedlings homozygous for recessive mutations in COP8, COP10, and COP11 failed to suppress the photomorphogenic developmental pathway and were unable to initiate skotomorphogenesis. As a consequence, the mutant seedlings grown in the dark had short hypocotyls and open and expanded cotyledons, with characteristic photomorphogenic cellular differentiation patterns and elevated levels of light-inducible gene expression. In addition, plastids of dark-grown mutants were defective in etioplast differentiation. Similar to cop1 and cop9, and in contrast to det1 (deetiolated), these new mutants lacked dark-adaptive change of light-regulated gene expression and retained normal phytochrome control of seed germination. Epistatic analyses with the long hypocotyl hy1, hy2, hy3, hy4, and hy5 mutations suggested that these three loci, similar to COP1 and COP9, act downstream of both phytochromes and a blue light receptor, and probably HY5 as well. Further, cop8-1, cop10-1, and cop11-1 mutants accumulated higher levels of COP1, a feature similar to the cop9-1 mutant. These results suggested that COP8, COP10, and COP11, together with COP1, COP9, and DET1, function to suppress the photomorphogenic developmental program and to promote skotomorphogenesis in darkness. The identical phenotypes resulting from mutations in COP8, COP9, COP10, and COP11 imply that their encoded products function in close proximity, possibly with some of them as a complex, in the same signal transduction pathway.

Arabidopsis↗
PubMed1994

Laryngotracheal stenosis: a serious complication of percutaneous tracheostomy.

Tracheostomy in patients requiring prolonged artificial ventilation in intensive care is increasingly being performed by a percutaneous dilatational technique, in preference to the standard surgical method. Since its introduction numerous series have reported favourably on its general safety in the short-term, but there have been few reports of longer term follow-up of patients. We present four cases of laryngotracheal stenosis, a previously unreported complication associated with the technique, and discuss the relevance of these to the future practice of percutaneous tracheostomy.

Adult↗