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Biomedical subjects

L Kern

Publications and source records attributed to L Kern.

35 records · Page 2Linked to original sources
PubMed1990

The FUR1 gene of Saccharomyces cerevisiae: cloning, structure and expression of wild-type and mutant alleles.

The FUR1 gene of Saccharomyces cerevisiae encodes uracil phosphoribosyltransferase (UPRTase) which catalyses the conversion of uracil into uridine 5'-monophosphate (UMP) in the pyrimidine salvage pathway. The FUR1 gene is included in a 2.1 kb genomic segment of DNA and is transcribed into a 1 kb poly(A)+mRNA. Sequencing has determined a 753 bp open reading frame capable of encoding a protein of 251 amino acids. The FUR1 genes for three recessive fur1 alleles, having different sensibilities to 5-fluorouridine (5-FUR) but identical levels of resistance to 5-fluorouracil (5-FU), were cloned and sequenced. Single bp changes located in different regions of the gene were found in each mutant. Two in vitro-constructed deletions of the FUR1 gene have been integrated at the chromosomal locus, giving strains with 5-FURR and 5-FURR mutant phenotype. Assays of UPRTase, uridine kinase, uridine ribohydrolase and uridine 5'-monophosphate nucleotidase enzymatic activities, in extracts of strains where the FUR1 gene is overexpressed or deleted, indicate that the FUR1 encoded protein possesses only UPRTase activity.

Alleles↗
PubMed1990

Morphological and immunohistochemical investigations of the utriculus prostaticus from the fetal period up to adulthood.

We investigated the utriculus prostaticus from the fetal period up to adulthood in 148 prostates. During the second half of gestation the utriculus had a simple tubular or a cystic form and was lined with metaplastic squamous epithelium which showed immunohistochemical positivity for different keratins, carcinoembryonic antigen, and peanut agglutinin binding sites. After birth, alveolar outgrowths of the utriculus developed. After puberty, the utriculus had become a complicated and variable structure. The epithelium no longer differed from that of the prostate glands either morphologically or immunohistochemically. Within the epithelium numerous endocrine cells were found containing neuron-specific enolase, chromogranin, and serotonin. The utriculus and ejaculatory ducts were embedded in a fibrous stroma with, after birth, numerous plexus-like blood vessels. This fibrous zone was peripherally bordered by a layer of smooth muscle. There was no evidence for a function of the utriculus differing from that of the prostate glands. Since the epithelium of both structures is identical immunohistochemically, the epithelium of the sinus urogenitalis most likely particpates in the lining of the utriculus during embryogenesis.

Adolescent↗
PubMed1990

Cloning and sequencing of URA10, a second gene encoding orotate phosphoribosyl transferase in Saccharomyces cerevisiae.

Orotate phosphoribosyl transferase (OP-RTase) catalyses the transformation of orotate to OMP in the pyrimidine pathway. In the yeast Saccharomyces cerevisiae, the URA5 gene is known to encode this enzyme activity. In this paper we present the cloning and sequencing of a yeast gene, named URA10, encoding a second OPRTase enzyme. Comparison of the predicted amino acid sequences between URA5 and URA10 genes shows more than 75% similarity. These sequences have also been compared to those of Escherichia coli, Podospora anserina, Sordaria macrospora and Dictyostelium discoideum. Remarkable similarities in the primary structure of these proteins have been found. Gene disruption experiments revealed that URA10 gene expression is responsible for the leaky phenotype of a ura5 mutant. Assays of OPRTase activity in extracts from ura5 and ura10 mutants indicate that the URA10 product contributes only 20% of the total activity found in wild type cells.

Amino Acid Sequence↗
PubMed1990

Nursing interventions for families of cardiac surgery patients.

Caring for the cardiac surgery patient includes intervening with the patient's family members. It is important for the nurse to acquire the knowledge base to implement appropriate interventions with family members. An intervention program was designed to meet the needs of family members of cardiac surgery patients based on a compilation of previous research data. This program included providing educational classes for the nursing staff as well as giving written information and support to the family member while visiting in the intensive care unit. A visiting intervention checklist was given to each nurse to initiate for each family member at all visits. Family members who received the intervention program reported higher satisfaction of needs and lower anxiety levels than those family members who did not receive the program.

Cardiac Surgical Procedures↗
PubMed1984

Incidence and significance of early pericardial effusions after cardiac surgery.

Echocardiography (echo) is frequently performed postoperatively to evaluate patients suspected of having cardiac tamponade or pericarditis. The overall incidence and significance of echocardiographic pericardial effusions (PE) early after cardiac surgery are unknown. Therefore, M-mode and 2-dimensional (2-D) echo were used to study 39 stable patients 4 to 10 days after cardiac surgery. Twenty-two patients (56%) had unequivocal moderate-to-large PEs. PEs were identified on serial chest x-rays in only 6 patients. PEs were significantly more common after heavy postoperative bleeding, and occurred in 16 of 19 patients with more than 500 ml of total chest tube output; only 6 of 20 patients with chest tube output less than 500 ml had PE. There was no correlation of PE by echo with pericardial friction rubs, chest pain or atrial arrhythmias. Elevated erythrocyte sedimentation rate did not correlate with PE by echo or clinical pericarditis. In 1 of 22 patients with PE, tamponade developed, and the patient required reoperation on day 5; the other 21 were discharged without related therapy. Thus, early postoperative PEs are common and related to postoperative bleeding. Because they do not correlate with symptoms of pericarditis and rarely lead to tamponade, their identification is usually of limited clinical significance.

Adult↗
PubMed1984

The influence of vigorous versus mild exercise on autistic stereotyped behaviors.

A major problem encountered in many autistic children is their high rate of stereotypic behavior, which has been shown to interfere with on-task responding and other appropriate behaviors. Since the experimental literature indicates that physical exercise can positively influence both appropriate and inappropriate behaviors, including the children's stereotypic behaviors, the purpose of this study was to investigate whether the specific type of exercise (i.e., mild vs. vigorous) would differentially affect subsequent stereotyped behaviors. The results demonstrated that (1) 15 minutes of mild exercise (ball playing) had little or no influence on the children's subsequent stereotyped responding, and (2) 15 minutes of continuous and vigorous exercise (jogging) was always followed by reductions in stereotyped behaviors. These results are discussed in relation to cognitive, physiological, and educational implications.

Autistic Disorder↗
PubMed1982

The effects of physical exercise on self-stimulation and appropriate responding in autistic children.

A major problem encountered with autistic children is their characteristic self-stimulatory behavior, which frequently interferes with on-task responding and other appropriate behaviors. However, the experimental literature suggests that with many populations, increased physical activity might positively influence subsequent responding. Therefore, the purpose of this study was to investigate the use of increased physical activity (in this experiment, jogging) as a possible method of decreasing subsequent self-stimulatory behaviors as well as increasing subsequent appropriate responding. Seven autistic children with exceptionally high levels of self-stimulatory behavior participated in the investigation. Self-stimulatory and appropriate behaviors were measured both before and after jogging in a repeated-reversal design. The results demonstrated the following: (1) Brief jogging sessions produced decreases in subsequent levels of self-stimulatory behaviors and also produced increases in appropriate play and academic responding; (2) These changes after jogging were evident in three different experimental settings: during academic responding on preschool level tasks' in a clinic; during ball-playing in an outside play area; and in a quiet room, while no other activity was occurring; (3) Supplementary measures obtained in an applied classroom setting showed a similar relationship with both increases in on-task activity and general interest ratings for school tasks following the jogging sessions.

Adolescent↗
PubMed1982

'Pseudodiagnosticity' in an idealized medical problem-solving environment.

Sixty-five senior medical students chose symptom information that would allow them to assess which of two diagnoses was more appropriate for hypothetical patients. Although Bayes' theorem should have governed their data selection, 83 percent of the subjects did not choose the symptom information required for Bayesian computation. Instead, they showed an overwhelming tendency to seek data relevant to a single disease, while ignoring information related to an equally plausible alternative diagnosis. The tendency for subjects to select diagnostically irrelevant information in such tasks has been labeled "pseudodiagnosticity." The effect result from the difficulty of simultaneously evaluating the relevance of a single symptoms in relation to single diagnosis. Medical educators might incorporate classroom demonstrations of the pseudodiagnosticity effect in order to increase students' accuracy in differential diagnosis.

Bayes Theorem↗
PubMed1979

[Hypochlorhydria in acute gastritis (author's transl)].

After swallowing a non-sterilised pH electrode a 25-year-old medical student developed an influenza-like illness followed by hypo- and achlorhydria for several weeks, acute leukocyte-gastrititis, and epithelial defects of the antrum. This possibly represents an infectious disease which can be transmitted by contaminated electrodes or probes.

Achlorhydria↗
PubMed1979

How reliable is determination of ulcer size by endoscopy?

The suface areas of 23 artificial ulcers in a rubber manikin and of 35 ulcers in 35 consecutive patients admitted for endoscopy of the upper gastrointestinal tract were estimated by six endoscopists. Of the 138 estimations made in the manikin 80% underestimated the true size of the ulcer: the mean (+/- SD) was -29 +/- 40%. The largest and the smallest estimate of the same ulcer by different endoscopists varied on average by a factor of 4.5 +/- 3.8, and the estimates by the same endoscopists of ulcers with the same size varied by a factor of 2.3 +/- 0.6. In the patients the scatter of the estimates was even larger, the mean factor being 7.8 +/- 6.3. Changes in ulcer size are therefore an unsuitable criterion for assessing ulcer healing. Even if consecutive examinations are performed by the same endoscopist, changes in ulcer area smaller than by a factor of 3 are not discernible.

Endoscopes↗
PubMedDate not supplied

Analysis and intervention with two topographies of challenging behavior exhibited by a young woman with autism.

A functional analysis was conducted with a young woman who engaged in both self-injury and aggression. Self-injury functioned to access preferred stimuli while aggression served an escape function. Intervention, a package consisting of gradually increasing the delay to reinforcement (access or escape), mand training, and extinction was effective for decreasing self-injury. However, this intervention was less effective in reducing aggression. A modification of the intervention, in which the gradual delay procedure was eliminated, resulted in reductions in aggression. The findings are discussed in the context of assessment and intervention selection with individuals who engage in multiple topographies of challenging behavior.

Adolescent↗
PubMedDate not supplied

Decreased cardiac output in the critical care setting.

The specific aim of this exploratory, descriptive study was to demonstrate that the nursing diagnosis, decreased cardiac output, contains at least seven separate and specific components. Forty critical care nurses completed a questionnaire about seven different case studies, or vignettes. Each vignette reflected one of the following: myocardial injury, arrhythmias, decreased preload, myocardial ischemia, increased afterload, drug effects, and cardiac surgery alterations. Mean scores were used to validate the specific subcategories. Analyses of variance were used to demonstrate statistically significant differences among them. Six of the labels were supported, providing preliminary evidence for the validity of these components of decreased cardiac output.

Adult↗
PubMedDate not supplied

"Pseudo" twin-to-twin transfusion syndrome and fetal outcome.

OBJECTIVE: To assess the fetal outcome, in a tertiary center, in pregnancies with suspected twin-to-twin transfusion syndrome (TTTS) not confirmed using ultrasonographic examination, diagnosis of pathology, or both. STUDY DESIGN: Forty-four pregnancies with suspected TTTS were followed longitudinally using ultrasonographic examination until delivery. The minimal criteria for the diagnosis of TTTS were: (1) suspicion of monochorionicity gleaned from ultrasound examination (to be confirmed at birth); (2) presence of polyhydramnios in one gestational sac (either assessed subjectively--or, finding that the largest vertical pocket of amniotic fluid was >8 cm in diameter before 20 weeks' gestation and >10 cm in diameter thereafter); and (3) presence of oligohydramnios in the other gestational sac (finding either that there was a "stuck" twin complication or that the largest vertical pocket of amniotic fluid was <1 cm in diameter). When one of the above criteria was not present, the pregnancy was defined as "pseudo" TTTS. Fetal outcome in "pseudo" TTTS was analyzed according to the relative size of the neonate (large or small) and whether the cord insertion was normal or velamentous. RESULTS: There were 18 cases of "pseudo" TTTS. No treatment in utero was necessary in any of the 18 pregnancies. The mean gestational age was 21.9 +/- 3.7 (1 SD) weeks at diagnosis and 33.0 +/- 3.0 weeks at delivery. The average weight discrepancy between the twins at birth was 34.3 +/- 14.8%. There were three fetal demises of the small twin and one neonatal demise of the large twin (p > 0.05). Large twins developed respiratory distress syndrome (RDS) more often than small twins (p < 0.05). Five percent of the large twins and 50% of the small twins had a velamentous insertion of the cord (p < 0.05). CONCLUSION: In pregnancies complicated by "pseudo" TTTS our data indicate that: (1) small twins have abnormal cord insertion more frequently than large twins, (2) large twins develop RDS more frequently than small twins. Our data suggest that the perinatal mortality in these pregnancies appears to be lower than that reported for the classical TTTS.

Amniocentesis↗