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Biomedical subjects

D Wood

Publications and source records attributed to D Wood.

At least 163 records · Page 9Linked to original sources

Barriers to medical care for homeless families compared with housed poor families.

To evaluate health access and health services utilization of homeless families we selected a systematic sample of 194 homeless families from 10 shelters in Los Angeles and 196 housed poor families from the same geographic regions of Los Angeles selected from welfare offices. Both samples relied primarily on Medicaid for their health insurance (61% and 96%). However, more homeless families than housed poor families were currently uninsured (26% vs 2%), had lost health insurance over the past year (50% vs 21%), and had spent a greater percentage of the past year uncovered by health insurance (22% vs 6%). Homeless families were much less likely to report a regular provider for preventive care (81% vs 94%) or for sick care (72% vs 95%). Moreover, of those reporting a regular provider, homeless families were more likely than housed poor families to use emergency departments or clinics rather than private offices for both preventive care (35% vs 15%) and sick care (37% vs 26%). Barriers to health care more frequently prevented homeless families from obtaining care (38% vs 28%). These findings suggest that homeless families have greater problems of access to health care than other poor families, related to lack of insurance, lack of a regular primary care provider, and other barriers. Programs to address these barriers for homeless families are presented.

Adult↗

The GTPase stimulatory activities of the neurofibromatosis type 1 and the yeast IRA2 proteins are inhibited by arachidonic acid.

Three proteins, GTPase activating protein (GAP), neurofibromatosis 1 (NF1) and the yeast inhibitory regulator of the RAS-cAMP pathway (IRA2), have the ability to stimulate the GTPase activity of Ras proteins from higher animals or yeast. Previous studies indicate that certain lipids are able to inhibit this activity associated with the mammalian GAP protein. Inhibition of GAP would be expected to biologically activate Ras protein. In these studies arachidonic acid is shown also to inhibit the activity of the catalytic fragments of the other two proteins, mammalian NF1 and the yeast IRA2 proteins. In addition, phosphatidic acid (containing arachidonic and stearic acid) was inhibitory for the catalytic fragment of NF1 protein, but did not inhibit the catalytic fragments of GAP or IRA2 proteins. These observations emphasize the biochemical similarity of these proteins and provide support for the suggestion that lipids might play an important role in their biological control, and therefore also in the control of Ras activity and cellular proliferation.

Arachidonic Acid↗

Glass ceramic approach to controlling the properties of a glass-ionomer bone cement.

Glass-ionomer dental cements have potential as bone cements in joint replacement surgery. However, commercially available glasses used in dental cements suffer from the loss of fluorine during the melting procedure and from phase separation of the glass upon quenching, giving rise to inter- and intra-batch variation. A model glass was examined in which minimal loss of fluorine is observed. This results in a glass whose composition is reproducible between batches. This glass will crystallize both above and below the glass transition temperature following heat treatments. Cements can be produced whose properties vary with the degree of crystallinity of the glass-ceramic. A commercial glass was also examined and was found to crystallize to an apatite phase.

Bone Cements↗

Antigenic structure of chimeras of type 1 and type 3 polioviruses involving antigenic sites 2, 3 and 4.

Chimeric polioviruses have been made in which regions of the type 1 Sabin strain corresponding to antigenic sites 2, 3 and 4 have been replaced by the corresponding regions of the type 3 Sabin strain. Manipulation of one site or a component of it generally did not affect the reactions of the others, suggesting that they form independent structural features. The extent to which the inserted site expressed the antigenic properties of type 3 could be assessed by reaction with polyclonal or monoclonal antibodies, or by immunogenicity. Site 2 could be expressed on infectious virus and site 3 on heated non-infectious virus (C antigen), but not on the native virion. The results are consistent with the view that sites consisting of a continuous sequence of amino acids may be presented on chimeras, whereas more complex sites, such as site 4 or site 3 of the native virion, are transferred less readily from type 3 to type 1.

Amino Acid Sequence↗

Intestinal absorption of the intact peptide carnosine in man, and comparison with intestinal permeability to lactulose.

1. Healthy humans ingested the dipeptide carnosine (L-beta-alanyl-L-histidine). Their plasma levels and urinary outputs of carnosine and beta-alanine were monitored over the following 5 h. 2. Large amounts of intact carnosine (up to 14% of the ingested dose) were recovered in the urine over the 5 h after ingestion. However, carnosine was undetectable in the plasma unless precautions were taken to inhibit blood carnosinase activity ex vivo during and after blood collection. 3. The amount of carnosine recovered in urine varied substantially between subjects. It correlated negatively with carnosinase enzymic activity in the plasma. Highest carnosinase activities were observed in those subjects who regularly underwent physical training. 4. Urinary recovery of the disaccharide lactulose also varied considerably between subjects, but was substantially lower than that of carnosine. There was no significant correlation between the recoveries of carnosine and lactulose. 5. When lactulose was ingested with a hypertonic solution, the urinary recovery of lactulose was generally increased. When carnosine was ingested with a hypertonic solution, the urinary recovery of carnosine was reduced: hence the paracellular route probably is not dominant for absorption of intact carnosine. 6. Intact carnosine must have crossed the intestine to an extent much greater than hitherto recognized. Rapid post-absorptive hydrolysis is a severe obstacle to quantification of intact peptide absorption.

Adult↗

The relationship between neuropsychological measures and self-care skills in patients with cerebrovascular lesions.

The present investigation examined the relationship between performance on the Michigan Neuropsychological Battery (MNB) and selected self-care skills in a group of patients with unilateral cerebrovascular lesions. Among MNB measures, left-sided somatosensory and motor functions were the best predictors of self-care skills, showing that in these stroke patients lower level cerebral functions mediated by the right hemisphere are more strongly related to the self-care skills examined than higher cerebral functions. Also, evidence that patients with cerebrovascular lesions in the left hemisphere performed better than patients with right hemisphere lesions in several self-care categories is further indication that right hemisphere processes have a special role to play in the mediation of these self-care activities. The research and clinical implications of these findings are noted.

Activities of Daily Living↗

Neuropsychological studies of blacks with cerebrovascular disorders: a preliminary investigation.

Very few studies have been conducted that examine brain behavior functions in blacks and other ethnic minorities. Recognizing that measures of higher cortical functions have cultural, experiential, and organic determinants, the present investigation was designed to ascertain whether findings reported in neuropsychologic studies of white patients with lateralized cerebral lesions are applicable to groups of black patients with lesions in similar locations. Thirty-seven patients with left (n = 15) and right (n = 22) cerebrovascular lesions were administered the Michigan Neuropsychological Battery (MNB). This battery is comprised of a number of objective standardized measures of higher and lower-level cerebral functions. With one exception, the performance of patients in the brain-injured groups was not systematically different on tests of higher brain functions. As expected, tests of lower-level somatosensory and motor functions showed a pattern of greater impairment on the side of the body contralateral to the lesion. But, in contrast to neuropsychological studies of white patients, a pattern of laterality specific deficits on verbal IQ and performance IQ was not observed. Methodological and theoretical implications of these findings are discussed.

Analysis of Variance↗

The catalytic domain of the neurofibromatosis type 1 gene product stimulates ras GTPase and complements ira mutants of S. cerevisiae.

Sequencing of the neurofibromatosis gene (NF1) revealed a striking similarity among NF1, yeast IRA proteins, and mammalian GAP (GTPase-activating protein). Using both genetic and biochemical assays, we demonstrate that this homology domain of the NF1 protein interacts with ras proteins. First, expression of this NF1 domain suppressed the heat shock-sensitive phenotype of yeast ira1 and ira2 mutants. Second, this NF1 domain, after purification as a glutathione S-transferase (GST) fusion protein, strongly stimulated the GTPase activity of yeast RAS2 and human H-ras proteins. The GST-NF1 protein, however, did not stimulate the GTPase activity of oncogenic mutant ras proteins, H-rasVal-12 and yeast RAS2Val-19 mutants, or a yeast RAS2 effector mutant. These results establish that this NF1 domain has ras GAP activity similar to that found with IRA2 protein and mammalian GAP, and therefore may also regulate ras function in vivo.

Cloning, Molecular↗

Genetic mapping of chronic childhood-onset spinal muscular atrophy to chromosome 5q11.2-13.3.

SPINAL muscular atrophy (SMA) describes a group of heritable degenerative diseases that selectively affect the alpha-motor neuron. Childhood-onset SMAs rank second in frequency to cystic fibrosis among autosomal recessive disorders, and are the leading cause of heritable infant mortality. Predictions that genetic heterogeneity underlies the differences between types of SMA, together with the aggressive nature of the most-severe infantile form, make linkage analysis of SMA potentially complex. We have now analysed 13 clinically heterogeneous SMA families. We find that 'chronic' childhood-onset SMA (including intermediate SMA or SMA type II, and Kugelberg-Welander or SMA type III) is genetically homogeneous, mapping to chromosomal region 5q11.2-13.3.

Adolescent↗

Cystadenocarcinoma of the pancreas: neo-adjuvant therapy and CEA monitoring.

Cystadenocarcinoma of the pancreas is generally considered to be unresponsive to chemotherapy and radiation therapy. We present two cases of laparotomy-proven unresectable cystadenocarcinoma which responded to intravenous 5-fluorouracil (1,000 mg/m2/24 hr x 5 days x 2) and 4,000 rads of radiation therapy. Both patients had objective response with marked shrinkage of the tumor as determined by clinical examination and computed tomography. At reexploration both tumors had become completely resectable with histologically clear margins and negative lymph nodes. Carcinoembryonic antigen (CEA) levels were elevated in both patients at initial presentation (86 and 71 ng/ml). The CEA levels declined to 19.9 and 66.0 ng/ml, respectively, after neo-adjuvant therapy, and both fell to normal levels after resection. Although surgical resection has been considered the only curative therapy for patients with pancreatic cystadenocarcinoma, we suggest that preoperative irradiation and chemotherapy may reduce the size of seemingly unresectable tumors. We also recommend serial CEA determinations in patients with levels initially elevated as a marker of the response to neo-adjuvant and operative therapy.

Carcinoembryonic Antigen↗

Characterisation of Chlamydia psittaci isolated from a horse.

This paper describes the isolation and characterisation of a strain of Chlamydia psittaci obtained from a nasal swab taken from a horse with serous nasal discharge. Initial isolation was achieved in cycloheximide-treated McCoy cell monolayers. Chlamydial inclusions stained by immunofluorescence either with a rabbit antiserum raised against C. psittaci or with a monoclonal antibody directed against the genus-specific lipopolysaccharide antigen were single and compact. They did not stain with iodine or with a monoclonal antibody reactive against Chlamydia trachomatis. The agent was re-isolated in the yolk sacs of embryonated hens eggs and designated N16. Identification of the agent was confirmed by electron microscopy. Unique plasmid DNA was prepared from a purified suspension of chlamydial elementary bodies (EBs), and analysed by electrophoresis through 1.0% agarose gels stained by ethidium bromide. This strain of C. psittaci grew relatively slowly in cycloheximide-treated McCoy cells, and the yield of elementary bodies during the course of one growth cycle was relatively low.

Animals↗

Antigenic structure of chimeras of type 1 and type 3 poliovirus involving antigenic site 1.

Chimeric polioviruses have been prepared in which part of the antigenic site 1-encoding sequence of the Sabin strain of type 1 poliovirus has been replaced by sequences based on those found in the homologous region of the Sabin type 3 strain. The chimeras were analysed for their reaction with polyclonal and monoclonal antibodies raised against type 1 and type 3 viruses, and with polyclonal antipeptide sera, as well as for their immunogenicity in animals. The effectiveness with which the type 3 site was presented antigenically varied in ways which were partially predictable, based on the behaviour of type 3 mutants with monoclonal antibodies. However, other factors were implicated which may include conformational effects and other components of the site in addition to those altered in the chimeras. The ability of the chimeras to induce antibodies reacting with type 3 polioviruses paralleled their antigenic reactivity, and evidence is presented for the induction of strain-specific antibodies.

Animals↗

Homeless and housed families in Los Angeles: a study comparing demographic, economic, and family function characteristics.

We studied 196 homeless and 194 housed poor families in Los Angeles, California to gain an understanding of events that precipitate family homelessness. Both homeless and housed poor mothers averaged 29 years old and were accompanied by two or three children. Three-fourths of both the homeless and housed families had income below the poverty level, and both groups expended almost two-thirds of their income on housing. Mothers in homeless families more commonly reported spousal abuse (35 vs 16 percent), child abuse (28 vs 10 percent), drug use (43 vs. 30 percent), or mental health problems (14 vs 6 percent) and weaker support networks. Homeless mothers more commonly came from homes where their parents abused drugs or alcohol (49 vs 34 percent) or more commonly lived outside the home or in foster care (35 vs 25 percent). Homelessness was reported as due primarily to economic pressures of housing costs, but personal and family problems frequently played a contributing role, especially for single parent families. Burdens of increasing housing costs and family dysfunction among housed poor families place many at risk for homelessness.

Adult↗

Echocardiographic evaluation of fetal arrhythmias.

When during routine prenatal care, the auscultation++ of the fetal heart beat reveals an abnormal rate or rhythm, two things are needed: 1) the accurate diagnosis of the arrhythmia, and 2) the hemodynamic impact of the rhythm disturbance on the fetus. In Poland, external cardiotocography is the most widely Supported in part by the American Heart Association, Delaware Affiliate, Grant = 41161 available diagnostic system used by obstetricians, but it records only the mean heart rate or the instantaneous heart rate. Cardiotocography is therefore useful only in identifying tachycardia or bradycardia. The most frequent tape of fetal arrhythmia is an irregular rhythm, especially premature contractions (1, 15, 18). We believe that any disturbance in fetal cardiac condition should be evaluated more fully by fetal echocardiography.

Arrhythmias, Cardiac↗

Adipose fatty acid composition and the risk of serious ventricular arrhythmias in acute myocardial infarction.

The relation between subcutaneous adipose tissue fatty acid composition and serious ventricular arrhythmias during acute myocardial infarction was studied in 2 groups of patients. In group 1 (n = 42), studied retrospectively, patients with ventricular fibrillation or tachycardia had a higher concentration of long-chain saturated fatty acids than those without (32.5 +/- 0.8% vs 29.7 +/- 0.4% [mean +/- standard error of the mean], p less than 0.01). In a prospective study, patients with arrhythmias (n = 106) had higher levels of long-chain saturated fatty acids (32.1 +/- 0.5% vs 30.7 +/- 0.4%, p less than 0.05) and of stearic acid (4.9 +/- 0.2% vs 4.4 +/- 0.1%, p less than 0.02) and a lower concentration of palmitoleic acid (7.3 +/- 0.3% vs 8.1 +/- 0.2%, p less than 0.005). When peak plasma creatine kinase concentrations were included with the individual fatty acid levels in a multiple logistic regression, only creatine kinase correlated significantly with ventricular arrhythmias (p less than 0.01). Thus, saturated fatty acids in cardiac membranes may lead to greater vulnerability to ventricular arrhythmias, although infarct size is the only statistically significant predictor after multiple regression analysis.

Adipose Tissue↗