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Biomedical subjects

K Schwartz

Publications and source records attributed to K Schwartz.

At least 163 records · Page 9Linked to original sources

Breastfeeding practices and lactation mastitis.

Clinical impression suggests that lactation mastitis is associated with inexperienced nursers, improper nursing techniques, stress and fatigue. A pilot study was conducted to describe the frequency of self-reported breastfeeding practices during the first week post partum among 100 breastfeeding women delivering at a freestanding birthing center or participating in an early discharge program. Nine cases of lactation mastitis were identified from the survey population and an additional 8 from the target population for the survey. Seventeen controls matched by delivery date were identified from survey participants. The frequency of self-reported breastfeeding practices, the presence of fatigue and stress during the week prior to the mastitis date in the case was compared among cases and controls. In the first week post partum, most women fed their babies every 2-3 hr for approx. 20 min a feeding. The cradle or Madonna position was the most frequently used nursing position. Nine percent reported supplementing feedings with formula. Women with mastitis were more likely than controls to report a history of mastitis with a previous child. In the week prior to the mastitis date of the case, women with mastitis were more likely than controls to report breast or nipple pain and cracks or breast fissures. They were less likely to report being able to take a daytime nap. Future studies should focus on the relative importance of and interrelationships among these factors.

Adult↗

The human apolipoprotein(a)/plasminogen gene cluster contains a novel homologue transcribed in liver.

Lipoprotein(a) is an atherogenic lipoprotein whose function and plasma concentration reflect the structure and regulation of the apolipoprotein(a) gene. Apolipoprotein(a) is a close homologue of plasminogen, and their genes are tightly linked on chromosome 6. To further characterize these genes, we analyzed overlapping human genomic yeast artificial chromosome clones, which revealed a cluster of four highly homologous genes encoding apolipoprotein(a), plasminogen, and two apolipoprotein(a)-related genes (rg) or pseudogenes. Hybridization analysis and reverse transcriptase polymerase chain reaction showed that one of these novel genes, designated apolipoprotein(a)rg-C, has a domain structure similar to apolipoprotein(a) and is transcribed in human liver. Three additional homologues designated as plasminogen-related genes are shown to be unlinked to this gene cluster and reside on chromosomes 2 and 4.

Apolipoproteins A↗

MCMI personality subtypes for male and female alcoholics.

Alcohol-dependent outpatients were clustered on the basis of their responses on the Millon Clinical Multiaxial Inventory (MCMI; Millon, 1983) personality disorder scales; male and female patients were clustered separately. The clusters were compared with respect to self-reported psychiatric, interpersonal, and drinking problems. The results, along with those of previous cluster analyses with male inpatients, suggest several reliable personality subtypes. One type (more common in inpatient settings) scores high on Negativistic and Avoidant/Schizoid or Dependent scales and reports numerous problems and intense distress. A second type (more common in outpatient settings) reports few problems and scores highest on Compulsive or Histrionic/Narcissistic scales. A third group (found in all and only male samples) scores high on Narcissism and Antisocial scales, readily admits substance problems, and may be interpersonally controlling and distancing.

Adolescent↗

[Physiopathology of mitral mechanics in hypertrophic cardiomyopathy. Groupe de travail "Cardiomyopathies et insuffisance cardiaque" de la Société Française de Cardiologie].

Ventricular hypertrophy, the only indisputable phenotypical marker of hypertrophic cardiomyopathy, is the basis of the physiopathology and treatment of the disease. Mitral valve abnormalities are usually considered to be secondary to the hypertrophy but the genesis of systolic anterior motion by the Venturi effect has been questioned by many clinical and experimental observations. Abnormalities of the mitral valve apparatus may in themselves (elongation of the valves, antero-internal malposition of the mitral papillary muscles and/or hyperlaxicity of antero-internal corhdae tendinae) create systolic anterior motion or subaortic obstruction in the absence of septal hypertrophy and/or increased subaortic flow velocities. Anatomo-clinical studies have confirmed this hypothesis: a high prevalence of mitral valve disease (increased valvular surface and length) has been found in hypertrophic cardiomyopathy. The recognition of these abnormalities is of value from the therapeutic (mitral valvuloplasty) diagnostic (in borderline cases) and genetic (when the primary nature of the abnormalities is confirmed) points of view.

Animals↗

Evaluating Bhola's Configurations Theory of Planned Change.

In Bhola's Configurations Theory of Planned Change, the CLER Structure resides in the midst of an epistemic triangle comprised of systems theory, dialectical thinking and constructivism. Our evaluation process compared the theory with descriptive statements in the Tiffany/Lutjens Planned Change Theory Evaluation Scale and found that Bhola's Theory resonates well with nursing's needs. This suggests its application to nursing's clinical, education, administrative, and research settings.

Models, Nursing↗

Nicotine patch.

Explore the source record for details and available documents.

Administration, Cutaneous↗

Evaluation of a rapid test to detect Streptococcus group A.

Rapid tests for the detection of group A beta-hemolytic streptococcus (GABHS) directly from a throat swab have become very popular. Previous studies have reported an antigen test sensitivity of 55-95% and a specificity of 88-100%. The present study evaluates the reliability of one rapid test in detecting GABHS (PathoDx). A total of 164 throat swab specimens was taken. GABHS was isolated on the culture in 37 (22.5%), and the rapid test was positive in 60 (36.6%). The sensitivity of the rapid test was 86.5% and the specificity 80%. Of the 60 positive rapid test results, 28 (47%) were false positive and the positive predicted value was 53%. We conclude that results obtained using rapid test kits should be compared to throat cultures in order to determine the reliability of such kits in specific clinical settings.

Humans↗

Impact of molecular genetics in cardiac diseases.

Genetic linkage mapping has become an important technology applied to the study of human biology and in particular, for the delineation of the molecular basis of diseases through gene isolation and characterization of mutations in DNA. This approach was applied to cardiac hereditary disorders only a few years ago through the analysis of familial hypertrophic cardiomyopathy and congenital long QT syndrome. For both diseases, there is a striking genetic heterogeneity and analyses of genotype-phenotype correlations are underway. Familial occurrence is likely to play also an important role in idiopathic dilated cardiomyopathy. Genetic testing and risk stratification will be more complicated than it was initially expected, but hope is now there to discover new ways for preventing, diagnosing and treating deadly cardiac disorders.

Cardiomyopathy, Dilated↗

Clinical and genetical heterogeneity of familial hypertrophic cardiomyopathy.

Familial hypertrophic cardiomyopathy (FHC) is an autosomal dominant disease which has a benign clinical course in most patients but carries also the risk of sudden cardiac death. Initial genetic studies have revealed the beta-myosin heavy chain (beta-MHC) gene on chromosome 14q11-q12 as morbid gene. Several mutations have been identified, almost all of them are missense mutations of the area in the gene coding for the globular head region of the myosin. The codon 403 has been found to be a hot-spot for mutations. Both, mutant myosin messenger RNA and proteins have been found in cardiac and in skeletal muscle, indicating the presence of a normal protein synthesis of the mutant allele. Histological studies show that gross alterations in protein assembly do not occur (e.g. by introducing the 403Arg-->Gln mutation in cell expression systems) and in-vitro motility of distinct mutations may be reduced in comparison to wild type myosin. The exact mechanism, however, how myosin mutations cause FHC has not yet been elucidated. Three novel loci for FHC have been identified only recently on chromosomes 1q3, 11p13-q13, and 15q22. It can be hoped that the characterization of the morbid genes in these loci will provide valuable information for the clarification of the pathogenesis of FHC and possibly for future therapeutic approaches. The challenge for future studies is to identify the morbid genes of the new loci, their mutations and their proteins.

Calmodulin-Binding Proteins↗

5' control regions of the apolipoprotein(a) gene and members of the related plasminogen gene family.

Elevated blood levels of apolipoprotein(a), the component of lipoprotein(a) that distinguishes it from low density lipoprotein, are a major risk factor for atherosclerosis. The apolipoprotein(a) gene is highly similar to the plasminogen gene and to at least four other genes or pseudogenes. The 5' untranslated and flanking sequences of these six genes contain extensive regions of near identity and share sequence elements involved in the initiation of transcription and translation. About 1000 base pairs of flanking DNA of each gene are sufficient to promote transcription in cultured hepatocytes. The apolipoprotein(a) gene promoter contains functional interleukin 6-responsive elements, consistent with the reported acute-phase response of apolipoprotein(a). Flanking genomic fragments of the apoliprotein(a) gene from two individuals with vastly different plasma apolipoprotein(a) concentrations have sequence differences that are reflected in differences in the rate of in vitro transcription.

Apolipoproteins↗

Contractile protein gene expression in serum-free cultured adult rat cardiac myocytes.

The effects of two adhesion substrates (serum and laminin) and time in culture on the expression of genes encoding myosin heavy chain (MHC) isoforms and alpha-skeletal actin were analysed in myocytes isolated from adult rat heart and maintained in serum-free culture. Relative messenger ribonucleic acid (mRNA) abundances were quantitated by dot-blot analysis. Gene expression was not influenced by the substrate used. Time in culture induced a decrease in total mRNA abundance and an up-regulation of beta-MHC and alpha-skeletal actin genes. It is proposed that atrophy of adult myocytes is associated with a pattern of gene expression similar to the fetal program.

Actins↗

The molecular biology of heart failure.

In the mammalian heart, the development of cardiac hypertrophy is a common feature that normally precedes all forms of heart failure. This adaptive process involves molecular changes in the myocardium, including the altered expression of several genes encoding proteins for contraction and relaxation. The expression of myosin heavy chain (MHC) and sarcomeric alpha-actin messenger ribonucleic acid (mRNA) changes qualitatively during cardiac hypertrophy; however, their accumulations are not coordinated. Skeletal alpha-actin transcripts accumulate throughout the ventricles and earlier than beta-MHC transcripts, which accumulate primarily around large coronary vessels. Skeletal alpha-actin transcripts also "hyperaccumulate" relative to cardiac alpha-actin mRNA, whose expression does not change. Expression of MHC isomRNA shows an inverse relation; as beta-MHC accumulates, alpha-MHC decreases in abundance. From nuclear run-on assays, we present evidence that the accumulation of these gene products is at least under partial transcriptional control with developmental growth, suggesting that those changes that occur with hypertrophy and heart failure may be primarily transcriptionally regulated. The expression of the mRNA for the calcium-adenosine triphosphate (Ca(2+)-ATPase) of the sarcoplasmic reticulum changes quantitatively with cardiac hypertrophy without the reexpression of a different isoform. The relative mRNA and protein concentrations for this protein diminish with both cardiac hypertrophy and heart failure, a change that may partially explain the delayed relaxation rates seen in hypertrophied and failing hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗

Exaggerated anesthetic requirements in the preferentially anesthetized brain.

BACKGROUND: The brain is assumed to be the site of anesthetic action, but anesthetics have effects elsewhere, such as the spinal cord. A preferentially anesthetized goat brain model was used to determine the importance of anesthetic action in the brain. METHODS: Six goats were anesthetized with isoflurane; after tracheal intubation and insertion of a femoral arterial catheter, bilateral neck dissections were performed to isolate the external carotid arteries and external jugular veins. The occipital arteries were ligated to prevent vertebral blood from entering the carotid system. (Goats do not have direct, significant vertebral artery contributions to the brain, and they lack internal jugular veins.) Control isoflurane minimum alveolar concentration (MAC) was determined using a dew-claw clamp as the painful stimulus. Following this, cranial venous blood was drained into a bubble oxygenator in which an isoflurane vaporizer was placed in line with the gas flow. Oxygenator arterial isoflurane concentration was estimated from the isoflurane partial pressure in the oxygenator exhaust. Isoflurane administration via the lungs was discontinued and the isoflurane partial pressure in the blood delivered via the carotid artery was increased by an amount required to bracket the partial pressures permitting and preventing movement in response to dew-claw stimulation. The native circulation was reestablished and MAC determined again. RESULTS: Cerebral isoflurane requirements were 1.2 +/- 0.3% (mean +/- SD) before bypass, increased to 2.9 +/- 0.7% during bypass when the brain was preferentially anesthetized, and decreased to 1.3 +/- 0.1% after bypass. CONCLUSIONS: The results support the importance of subcortical structures, such as the spinal cord, in the generation of purposeful movement in response to a painful stimulus under general anesthesia.

Anesthesia↗

Antithetical accumulation of myosin heavy chain but not alpha-actin mRNA isoforms during early stages of pressure-overload-induced rat cardiac hypertrophy.

Myocardial response to a hemodynamic overload involves changes in the expression of isogenes encoding myosin heavy chain (MHC) and actin: beta-MHC/alpha-MHC and skeletal/cardiac alpha-actin mRNA isoform ratios are increased. It is not known whether these changes are due to increased accumulations of the two neosynthesized transcripts, beta-MHC and skeletal alpha-actin, or whether the mRNA isoforms normally present, alpha-MHC and cardiac alpha-actin, are concomitantly decreased. To answer these questions, using dot-blot hybridizations, primer extension, and exonuclease VII mapping assays, we have analyzed the content of sarcomeric MHC and actin mRNAs in the poly(A+) RNA in left ventricles of 23-24-day-old rats 18 and 24 hours after a pressure overload induced by stenosis of the thoracic aorta. The results showed a 1.9-fold increase in poly(A+) RNA after the stenosis. Skeletal/cardiac alpha-actin mRNA isoforms were already increased fivefold (from 0.19 to 0.99) at 18 hours, and this was exclusively due to a 5.5-fold increase in skeletal alpha-actin mRNA. At 24 hours, this ratio was increased ninefold (from 0.14 to 1.22), and this was due to a 4.3-fold increase in the level of skeletal alpha-actin mRNAs (p < 0.001) and a 1.9-fold decrease of cardiac alpha-actin mRNA (p < 0.001), restoring the same proportion of sarcomeric actin mRNA in sham-operated and operated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗