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Biomedical subjects

K Sullivan

Publications and source records attributed to K Sullivan.

At least 91 records · Page 5Linked to original sources
PubMed1995

Autosomal dominant "Opitz" GBBB syndrome due to a 22q11.2 deletion.

We report on a family with autosomal dominant paternally inherited "Opitz" GBBB syndrome and an additional case with findings which have been reported in that syndrome. In each case the propositus presented with a vascular ring. Since a vascular ring may be a sign of a 22q11.2 deletion [Zacki et al., 1995], FISH (fluorescence in situ hybridization) studies were performed. These studies demonstrated a 22q11.2 deletion in the 3 affected individuals. Review of Opitz GBBB syndrome and the 22q11.2 microdeletion syndrome demonstrates significant overlap of manifestations including both facial characteristics and structural anomalies. Based on the phenotypic overlap and the presence of a 22q11.2 deletion in our patients with Opitz GBBB syndrome and the presence of a deletion in a patient with lung hypoplasia, absent pulmonary artery, and long segment tracheomalacia, we propose that, in some cases, the Opitz GBBB syndrome may be due to a 22q11.2 deletion. This enlarges the list of "syndromes" associated with the 22q11.2 deletion, which presently includes most patients with DiGeorge, velocardiofacial, and conotruncal anomaly face syndrome.

Abnormalities, Multiple↗
PubMed1995

Breastfeeding.

Explore the source record for details and available documents.

Breast Feeding↗
PubMed1995

beta-Tubulin mutation suppresses microtubule dynamics in vitro and slows mitosis in vivo.

Microtubule (MT) dynamics vary both spatially and temporally within cells and are thought to be important for proper MT cellular function. Because MT dynamics appear to be closely tied to the guanosine triphosphatase (GTPase) activity of beta-tubulin subunits, we examined the importance of MT dynamics in the budding yeast S. cerevisiae by introducing a T107K point mutation into a region of the single beta-tubulin gene, TUB2, known to affect the assembly-dependent GTPase activity of MTs in vitro. Analysis of MT dynamic behavior by video-enhanced differential interference contrast microscopy, revealed that T107K subunits slowed both the growth rates and catastrophic disassembly rates of individual MTs in vitro. In haploid cells tub2-T107K is lethal; but in tub2-T107K/tub2-590 heterozygotes the mutation is viable, dominant, and slows cell-cycle progression through mitosis, without causing wholesale disruption of cellular MTs. The correlation between the slower growing and shortening rates of MTs in vitro, and the slower mitosis in vivo suggests that MT dynamics are important in budding yeast and may regulate the rate of nuclear movement and segregation. The slower mitosis in mutant cells did not result in premature cytokinesis and cell death, further suggesting that cell-cycle control mechanisms "sense" the mitotic slowdown, possibly by monitoring MT dynamics directly.

Base Sequence↗
PubMed1995

Mortality study of construction workers in the UK.

BACKGROUND: Construction is one of the most dangerous industries in the world. However, there has been little literature on occupational epidemiology in this field. A study of the mortality experience over a 13-year period among construction workers in the UK was carried out. METHOD: This was based on 15,007 death certificates of members of the Building and Civil Engineering Holiday and Benefit Scheme, who had died during 1975 to 1987 aged 20-64 years. Proportional mortality ratio (PMR) and mortality odds ratio techniques were used. RESULTS: Significantly elevated PMR were found for deaths from all cancers, including cancer of the lung and stomach, and for accidental deaths. Associations were demonstrated between several job categories and an increased risk of cancer mortality. Occupational exposures to hazardous substances may have contributed to the elevated cancer mortality, although the study findings should be interpreted with caution. Inadequate supervision of safety procedures, together with a high proportion of young and inexperienced workers, may be associated with the high number of accidental deaths. CONCLUSIONS: The results support the hypothesis that working in the construction industry is associated with a high risk for accidental death and probably also for malignant diseases including lung, mesothelium and stomach cancers. Further epidemiological studies among construction workers are needed to support policies aimed at improving occupational health, including the prevention of accidents.

Accidents, Occupational↗
PubMed1995

Congestive heart failure: differential adaptation of the diaphragm and latissimus dorsi.

Diaphragm and latissimus dorsi muscle functions, histochemistries, and morphometries were studied in anesthetized male Yucatan minipigs with congestive heart failure (CHF) induced by supraventricular tachycardia (n = 5). Sham-operated animals served as a control group (n = 5). In CHF animals, transdiaphragmatic pressure measured during supramaximal phrenic stimulation was reduced by 40% at low frequencies (< or = 20 Hz) and by 60% at higher frequencies. Twitch amplitude and half-relaxation time were also decreased. The cross-sectional areas of type I, IIa, and IIb fibers were reduced in the diaphragm. The proportion of type I fibers increased, whereas type IIa fibers decreased. Succinate dehydrogenase activity was elevated in type IIa and IIb fibers, but diaphragmatic fatigability was not altered. CHF reduced latissimus dorsi isometric force by 40% for stimulation frequencies > or = 30 Hz. The cross-sectional area of latissimus dorsi type IIb fibers was decreased, but twitch characteristics, fiber type composition, succinate dehydrogenase activity, and fatigability were unchanged. Experimental CHF appears to cause greater intrinsic adaptive changes in the diaphragm compared with those in the latissimus dorsi in the minipig. For both muscles, reduced contractile function was associated with atrophy. Impaired performance of the diaphragm may also be attributed to an increase in the relative contribution of type I fibers to the total tension-generating capacity of the muscle and to the pathophysiological mechanisms underlying the shortened relaxation time of the twitch response.

Adaptation, Physiological↗
PubMed1995

Simultaneous DNA 'fingerprinting', diagnosis of sex and single-gene defect status from single cells.

Sex and cystic fibrosis status have been previously diagnosed separately at the single cell level. We have developed a sensitive, reliable, accurate and rapid (within 5-6 h) system for the simultaneous diagnosis of sex, cystic fibrosis and a DNA 'fingerprint' within a single reaction from a variety of single cells. As contamination cannot be totally excluded, particularly at the single cell level, DNA 'fingerprinting' can be used to assess the risk of contamination. High sensitivity with single cells is combined with very high specificity (estimated matching probability of 10(-7)-10(-8)), allowing the source of the amplified cell to be identified with a very high degree of probability. Fluorescent primers were multiplexed for six tetranucleotide microsatellite sequences to determine the DNA fingerprint; the amelogenin gene was used to diagnose sex, and primers for the CFTR region were used to determine cystic fibrosis (CF) status. Analysis of the fluorescent product was undertaken using an automated DNA sequencer with Genescan software. This technique has many applications such as prenatal and preimplantation diagnosis, forensic identification of small or degraded samples, and detection of contamination sources. DNA fingerprints of single haploid spermatozoa and other cells can be assessed, so ensuring the detection of both diploid and haploid contamination during preimplantation diagnosis.

Cystic Fibrosis↗
PubMed1994

Identification of protein-tyrosine phosphatases prevalent in adipocytes by molecular cloning.

Protein-tyrosine phosphatases (PTPases) are among the fastest growing family of enzymes that are closely linked to signal transduction pathways involving reversible tyrosine phosphorylation. In order to identify PTPase homologs expressed in adipocytes that might regulate the action of insulin or growth factors in this tissue, we screened a rat adipocyte cDNA library at reduced stringency with a panel of candidate PTPase probes. After subcloning and sequence analysis of the positive plaques, this approach enabled us to identify the expression of LRP/RPTP-alpha, PTPase 1B, SH-PTP2/Syp, and LAR in adipocytes at an abundance of 16, 7, 6 and 3 per million, respectively. Furthermore, a sequence variant of SH-PTP2/Syp was identified that may have significance in the tissue-specific activity of this enzyme. These data provide insight into PTPase homologs that may have a physiological role in the regulation of phosphotyrosyl turnover in hormone signalling pathways in adipocytes.

Adipocytes↗
PubMed1994

A second look at second-order belief attribution in autism.

Compared the performance of autistic and mentally retarded subjects, all of whom had passed a standard first-order test of false belief, on a new second-order belief task. 12 autistic and 12 mentally retarded subjects, matched on verbal mental age (assessed by PPVT and a sentence comprehension subtest of the CELF) and full-scale IQ were given two trials of a second-order reasoning task which was significantly shorter and less complex than the standard task used in all previous research. The majority of subjects in both groups passed the new task, and were able to give appropriate justifications to their responses. No group differences were found in performance on the control or test questions. Findings are interpreted as evidence for the role of information processing factors rather than conceptual factors in performance on higher order theory of mind tasks.

Adolescent↗
PubMed1994

Resistance to positional noise scales with target size.

The ability to judge the separation between two target lines deteriorates as the base separation increases. Several lines of evidence suggest that this may be due to larger base separations being processed by mechanisms that cover larger areas and which have a greater associated positional uncertainty as a consequence. Separation discrimination was measured as a function of base separation with randomly jittering targets. As predicted from the above models the resistance to positional noise increased in proportion to base separation of the targets. The data is incompatible with the suggestion that resistance to positional noise declines when the extent of the noise exceeds fixational instability.

Discrimination, Psychological↗
PubMed1994

Identification of the remains of the Romanov family by DNA analysis.

Nine skeletons found in a shallow grave in Ekaterinburg, Russia, in July 1991, were tentatively identified by Russian forensic authorities as the remains of the last Tsar, Tsarina, three of their five children, the Royal Physician and three servants. We have performed DNA based sex testing and short tandem repeat (STR) analysis and confirm that a family group was present in the grave. Analysis of mitochondrial (mt) DNA reveals an exact sequence match between the putative Tsarina and the three children with a living maternal relative. Amplified mtDNA extracted from the remains of the putative Tsar has been cloned to demonstrate heteroplasmy at a single base within the mtDNA control region. One of these sequences matches two living maternal relatives of the Tsar. We conclude that the DNA evidence supports the hypothesis that the remains are those of the Romanov family.

Base Sequence↗
PubMed1994

Predicting and explaining behavior: a comparison of autistic, mentally retarded and normal children.

The relationship between performance on a false belief task and a new task designed to elicit explanations of human action was examined in two experiments. In the first study normal preschoolers' performance on both tasks was significantly correlated. The second experiment included matched groups of autistic, mentally retarded, and older normal children. The autistic subjects were significantly worse than controls at offering mentalistic explanations. Performance on the false belief and the explanation of action tasks was highly correlated for the autistic subjects. These findings are discussed in terms of the relationships between language and theory of mind.

Autistic Disorder↗
PubMed1994

The impact of recent legislative change in Germany.

Cost-containment policies introduced in Germany under the 'Health Structure Act' at the beginning of 1993 marked a dramatic turnaround in German healthcare policy. The traditional arms-length approach of government policy makers, under which responsibility for implementation of the measures specified in national legislation was devolved upon the representatives of healthcare providers and statutory health insurance funds, was replaced by government mandates at the national level. These mandates-including price controls, a national pharmaceuticals budget and copayment changes-had a dramatic impact on the German healthcare system and on the German pharmaceutical market in particular. Eventually, these national controls are to be phased out as the associations of healthcare providers and health insurance funds negotiate the terms for implementation of further measures specified in the 'Health Structure Act': regional budgets, prescription guidelines, stricter controls of prescribing behaviour and a positive list. Despite this gradual return to the federalistic principles of the German healthcare system, the German pharmaceutical market will never be the same.

Budgets↗
PubMed1994

Issues in the assessment of nutritional status using anthropometry.

Four issues in the use and interpretation of anthropometry are discussed at the level of the population and of the individual. The first issue is the index or indices of choice: weight-for-height versus height-for-age versus weight-for-age. The selection of an index or indices depends upon many factors, and no one index is completely adequate in all situations. Proposed criteria are provided to assess the severity of low anthropometry within populations. The second issue is the scale of the index: z-scores (or standard deviations) versus percentiles versus percent-of-median. z-Scores have several properties that make them superior to the other two scales. A third issue deals with limitations in the current growth reference; one of these is the disjunction between the growth curves at 2 years of age, resulting from the use of two different populations in the reference. It is important that this disjunction be recognized by researchers so that the anthropometric findings are interpreted correctly for this age range. Lastly, some issues to do with the collection of single versus multiple anthropometric measurements on children are discussed.

Anthropometry↗
PubMed1993

Three-year-olds' understanding of mental states: the influence of trickery.

This study examined the claim that children under 4 cannot conceptualize false mental states. Fifty-one children between 3;0 and 4;2 were tested in a Standard and a Trick Condition. In the Standard Condition, children were given a modified version of the Smarties task developed by Hogrefe, Wimmer, and Perner (1986). In the Trick Condition, the Smarties task was modified so that children were required to trick another person by switching the contents of a familiar box. Results revealed that a majority of subjects responded correctly to Ignorance and False Belief Questions in the Trick Condition, but not in the Standard Condition. There were no differences in children's ability to attribute ignorance and false belief. These results suggest that even young 3-year-olds have the ability to attribute mental states that differ from their own, even though this ability has proved elusive and difficult to demonstrate.

Child, Preschool↗
PubMed1993

Renal transplantation in children and adolescents: the 1992 annual report of the North American Pediatric Renal Transplant Cooperative Study.

From January 1987 to January 1992 the North American Pediatric Renal Transplant Cooperative Study registered and followed 2,037 children and adolescents 17 years of age or less who received 2,197 renal transplants at 75 participating centers in the United States and Canada. The cumulative experience over 5 years of data collection demonstrated trends in renal transplantation practice for pediatric patients. The percentage of live donor organ recipients receiving donor-specific blood transfusions decreased from 40% in 1987 to less than 12% in 1991; random blood transfusions also were used less frequently during the most recent 2 years of the study. Immunosuppressive therapy on posttransplant day 0 or 1 with polyclonal and monoclonal antilymphocyte agents was used in over 40% of transplants. There was also a notable preference for the combined use of prednisone, azathioprine and cyclosporine as maintenance immunosuppression. The percentage of live donor source graft recipients receiving cyclosporine increased from 78% in 1987 to 90% in the most recent year, and considered together, nearly 90% of live donor and cadaver organ recipients received cyclosporine. The observed graft survival probabilities for live donor grafts were 88%, 83%, 81% and 76% at years 1-4 post transplantation, respectively. The 1st through 4th year graft survival probabilities for cadaver grafts were 74%, 68%, 63% and 58%, respectively. The five most common causes of pediatric end-stage renal disease have remained as: hypoplastic-dysplastic kidney, obstructive uropathy, focal segmental glomerulosclerosis, reflux nephropathy and systemic immunological diseases throughout the 5 years of this study. There has been a decrease in children 2 years of age or less undergoing transplant surgery. On average, 50% of graft failures were due to the various forms of rejection. Vascular thrombosis (14%) and recurrence of primary renal disease (7%) were the next most frequently encountered causes of graft failure. Poor linear growth was identified as a problem affecting the majority of children both before and after transplantation. Post transplant linear growth was best among recipients less than 6 years of age at transplantation and recipients of all ages who received alternate-day prednisone. A total of 16 malignancies were reported during the 5 years of study. A total of 105 deaths were reported, with infection (41%) the most common primary cause of death. The 2-year patient survival probabilities were 95.5% and 93% for recipients of live donor and cadaver grafts, respectively.

Adolescent↗