Biomedical subjects

W E Johnson

Publications and source records attributed to W E Johnson.

At least 37 records · Page 2Linked to original sources

PubMed1998

Stimulation of melanogenesis in a human melanoma cell line by bistratene A.

The polyether toxin, bistratene A, induced morphological and functional differentiation of a human melanoma cell line (MM96E). The cells became blocked at the G2/M transition and elaborated a number of processes. Tyrosinase activity and melanin content were substantially increased. Northern blot analysis showed up-regulation of mRNA for several genes known to be involved in melanin biosynthesis (pmel17, pmel34, and tyrosinase related proteins, TRP-1 and TRP-2). Bistratene A induced the phosphorylation of several proteins as assessed by 2D gel electrophoresis and one of these was identified as stathmin (oncoprotein 18), a cell-cycle regulated phosphoprotein. Bistratene A specifically induced the translocation of protein kinase Cdelta (PKCdelta) from a soluble to a particulate fraction without affecting other isoforms. These results implicate a role for protein kinase Cdelta in the induction of differentiation of this human melanoma cell line.

Acetamides↗

PubMed1998

Phylogeographic patterns and evolution of the mitochondrial DNA control region in two neotropical cats (Mammalia, felidae).

The ocelot (Leopardus pardalis) and margay (L. wiedii) are sister-species of Neotropical cats which evolved from a lineage that migrated into South America during the formation of the Panamanian land bridge 3-5 million years ago. Patterns of population genetic divergence of each species were studied by phylogenetic analyses of mitochondrial DNA (mtDNA) control region sequences in individuals sampled across the distribution of these taxa. Abundant genetic diversity and remarkably concordant phylogeographic partitions for both species were observed, identifying parallel geographic regions which likely reflect historical faunal barriers. Inferred aspects of phylogeography, population genetic structure, and demographic history were used to formulate conservation recommendations for these species. In addition, observed patterns of sequence variation provided insight into the molecular evolution of the mtDNA control region in closely related felids.

Animals↗

PubMed1997

Phylogenetic reconstruction of the Felidae using 16S rRNA and NADH-5 mitochondrial genes.

The Felidae family represents a challenge for molecular phylogenetic reconstruction because it consists of 38 living species that evolved from a relatively recent common ancestor (10-15 million years ago). We have determined mitochondrial DNA sequences from two genes that evolve at relatively rapid evolutionary rates, 16S rRNA (379 bp) and NADH dehydrogenase subunit 5 (NADH-5, 318 bp), from multiple individuals of 35 species. Based on separate and combined gene analyses using minimum evolution, maximum parsimony, and maximum likelihood phylogenetic methods, we recognized eight significant clusters or species clades that likely reflect separate monophyletic evolutionary radiations in the history of this family. The clusters include (1) ocelot lineage, (2) domestic cat lineage, (3) Panthera genus, (4) puma group, (5) Lynx genus, (6) Asian leopard cat group, (7) caracal group, and (8) bay cat group. The results confirm and extend previously hypothesized associations in most cases, but in others, e.g., the bay cat group, suggest novel phylogenetic relationships. The results are compared and evaluated with molecular, cytogenetic, and morphological data to derive a phylogenetic synthesis of field evolutionary history.

Animals↗

PubMed1997

Rates of nuclear and cytoplasmic mitochondrial DNA sequence divergence in mammals.

Differential rates of nucleotide substitution among different gene segments and between distinct evolutionary lineages is well documented among mitochondrial genes and is likely a consequence of locus-specific selective constraints that delimit mutational divergence over evolutionary time. We compared sequence variation of 18 homologous loci (15 coding genes and 3 parts of the control region) among 10 mammalian mitochondrial DNA genomes which allowed us to describe different mitochondrial evolutionary patterns and to produce an estimation of the relative order of gene divergence. The relative rates of divergence of mitochondrial DNA genes in the family Felidae were estimated by comparing their divergence from homologous counterpart genes included in nuclear mitochondrial DNA (Numt, pronounced "new might"), a genomic fossil that represents an ancient transfer of 7.9 kb of mitochondrial DNA to the nuclear genome of an ancestral species of the domestic cat (Felis catus). Phylogenetic analyses of mitochondrial (mtDNA) sequences with multiple outgroup species were conducted to date the ancestral node common to the Numt and the cytoplasmic (Cymt) mtDNA genes and to calibrate the rate of sequence divergence of mitochondrial genes relative to nuclear homologous counterparts. By setting the fastest substitution rate as strictly mutational, an empirical "selective retardation index" is computed to quantify the sum of all constraints, selective and otherwise, that limit sequence divergence of mitochondrial gene sequences over time.

Animals↗

PubMed1996

Outcome of respiratory symptoms after antireflux surgery on patients with gastroesophageal reflux disease.

OBJECTIVE: To investigate factors predictive of relief of respiratory symptoms associated with gastroesophageal reflux disease (GERD). DESIGN: A case series of patients with GERD and respiratory symptoms undergoing fundoplication from 1987 to 1994 at a tertiary care university hospital. PATIENTS: Of 118 patients undergoing fundoplication for cardinal symptoms of GERD, 63 had respiratory symptoms. Postoperative follow-up information was available in 50 patients at a median of 3 years. INTERVENTIONS: The presence of GERD was documented on the basis of barium swallow, esophagoscopy, esophageal manometry, and 24-hour pH studies. A standardized questionnaire was used to score symptoms. A Nissen fundoplication was performed in 39 patients, a Collis-Belsey fundoplication in 3 patients. MAIN OUTCOME MEASURES: A repeat standardized questionnaire was used to evaluate the response to surgery for each symptom experienced. Univariate analysis was performed to evaluate factors influencing outcome. RESULTS: Respiratory symptoms were present in 53% (63/118) of patients with GERD. Fundoplication relieved the respiratory symptoms in 76% (38/50) of the patients. Reflux symptoms were relieved in 86% (43/50) of the patients. Abnormalities of esophageal motility were present in 34% (17/50) of the patients, and these were significantly more common in patients who did not experience relief of their respiratory symptoms (9/12 vs 8/38, chi 2 = 9.54, P = .002). CONCLUSIONS: Respiratory symptoms are common in patients with GERD. Unlike classic reflux symptoms, the beneficial effects of antireflux surgery on respiratory symptoms are less predictable. The probability of relief of these respiratory symptoms with antireflux surgery is directly dependent on esophageal motor function.

Adult↗

PubMed1996

Genetic and phylogenetic divergence of feline immunodeficiency virus in the puma (Puma concolor).

Feline immunodeficiency virus (FIV) is a lentivirus which causes an AIDS-like disease in domestic cats (Felis catus). A number of other felid species, including the puma (Puma concolor), carry a virus closely related to domestic cat FIV. Serological testing revealed the presence of antibodies to FIV in 22% of 434 samples from throughout the geographic range of the puma. FIV-Pco pol gene sequences isolated from pumas revealed extensive sequence diversity, greater than has been documented in the domestic cat. The puma sequences formed two highly divergent groups, analogous to the clades which have been defined for domestic cat and lion (Panthera leo) FIV. The puma clade A was made up of samples from Florida and California, whereas clade B consisted of samples from other parts of North America, Central America, and Brazil. The difference between these two groups was as great as that reported among three lion FIV clades. Within puma clades, sequence variation is large, comparable to between-clade differences seen for domestic cat clades, allowing recognition of 15 phylogenetic lineages (subclades) among puma FIV-Pco. Large sequence divergence among isolates, nearly complete species monophyly, and widespread geographic distribution suggest that FIV-Pco has evolved within the puma species for a long period. The sequence data provided evidence for vertical transmission of FIV-Pco from mothers to their kittens, for coinfection of individuals by two different viral strains, and for cross-species transmission of FIV from a domestic cat to a puma. These factors may all be important for understanding the epidemiology and natural history of FIV in the puma.

Amino Acid Sequence↗

PubMed1995

Down-regulation but not phosphorylation of stathmin is associated with induction of HL60 cell growth arrest and differentiation by physiological agents.

Stathmin is a cytosolic phosphoprotein that has an important but, as yet, undefined role in cell proliferation and differentiation. Induction of growth arrest and differentiation of HL60 cells to monocytes by phorbol 12-myristate 13-acetate is associated with rapid phosphorylation of the protein. Stathmin phosphorylation was not seen when HL60 cells were induced to differentiate to monocytes, by 1 alpha, 25-dihydroxyvitamin D3, and to neutrophils, by all-trans retinoic acid and granulocyte colony stimulating factor. In all the above instances, stathmin expression was down-regulated. Thus, increased stathmin phosphorylation is not required for cell growth arrest or differentiation or down-regulation of stathmin expression.

Blotting, Western↗

PubMed1995

Central angiotensin II induces thirst-related responses in an amphibian.

Angiotensin II (A-II), a potent inducer of thirst-related behavior in many vertebrate species, was injected into the third ventricle of the brain of the spadefoot toad, Scaphiopus couchii. Following injection of 10 ng A-II the animals demonstrated a significant increase in water absorption response (WR) behavior, in which toads press their ventral skin to a moist surface and absorb water by osmosis. This increase in the frequency of WR behavior was positively correlated with an increase in water gain during a 2-hr period indicating that centrally injected A-II stimulates water intake by this amphibian species. We have previously demonstrated that WR behavior is also induced by intraperitoneal (i.p.) injections of A-II in several anuran species, including S. couchii. Thus, amphibians, like other vertebrates, demonstrate an increase in water intake in response to either centrally administered or circulating A-II. A second series of experiments was conducted to determine whether the above response to A-II might be secondary to increases in the circulating levels of aldosterone (ALDO) or antidiuretic hormone because the release of both of these hormones has been shown by others to be stimulated by A-II. Scaphiopus couchii injected i.p. with either ALDO or arginine vasotocin in dosages of 1, 10, and 100 micrograms/100 g body weight showed no increase in WR behavior relative to toads injected with saline alone. These results suggest that A-II acts directly on the brain of S. couchii to induce WR behavior.

Aldosterone↗

PubMed1994

Angiotensin II induces water absorption behavior in two species of desert anurans.

The octapeptide, angiotensin II (A-II), induces drinking behavior in several vertebrate species; however, relatively little is understood about A-II-induced thirst in amphibians. Scaphiopus couchii and Bufo cognatus were dehydrated to 90% of their ad libitum weight. This level of dehydration was sufficient to induce water absorption response (WR) behavior in both species. Fully hydrated toads injected intraperitoneally with A-II exhibited a significant amount of WR behavior. The minimum effective dose for inducing WR behavior was 10 micrograms/100 g-animal for S. couchii and 100 micrograms/100 g-animal for B. cognatus. When dehydrated toads were treated with the A-II receptor antagonist, Thr8-saralasin, S. couchii, exhibited a significant increase in WR behavior, while B. cognatus did not respond behaviorally. Finally, treatment of dehydrated toads with captopril, a compound that inhibits conversion of angiotensin I to A-II, did not significantly affect WR behavior in either species. These results support other findings that A-II may be involved in WR behavior in amphibians. However, the failure of Thr2-saralasin or captopril to inhibit WR behavior in dehydrated toads suggests that the receptor mechanisms involved in thirst regulation in toads may be different from those in mammals, and the renin-angiotensin system may not be the only potential mediator of WR behavior in these species.

Angiotensin II↗

PubMed1994

Phylogenetic reconstruction of South American felids defined by protein electrophoresis.

Phylogenetic associations among six closely related South American felid species were defined by changes in protein-encoding gene loci. We analyzed proteins isolated from skin fibroblasts using two-dimensional electrophoresis and allozymes extracted from blood cells. Genotypes were determined for multiple individuals of ocelot, margay, tigrina, Geoffroy's cat, kodkod, and pampas cat at 548 loci resolved by two-dimensional electrophoresis and 44 allozyme loci. Phenograms were constructed using the methods of Fitch-Margoliash and neighbor-joining on a matrix of Nei's unbiased genetic distances for all pairs of species. Results of a relative-rate test indicate changes in two-dimensional electrophoresis data are constant among all South American felids with respect to a hyena outgroup. Allelic frequencies were transformed to discrete character states for maximum parsimony analysis. Phylogenetic reconstruction indicates a major split occurred approximately 5-6 million years ago, leading to three groups within the ocelot lineage. The earliest divergence led to Leopardus tigrina, followed by a split between an ancestor of an unresolved trichotomy of three species (Oncifelis guigna, O. geoffroyi, and Lynchailuris colocolo) and a recent common ancestor of Leopardus pardalis and L. wiedii. The results suggest that modern South American felids are monophyletic and evolved rapidly after the formation of the Panama land bridge between North and South America.

Alleles↗

PubMed1994

Racial disparities in reported prenatal care advice from health care providers.

OBJECTIVES: The relationship between certain maternal behaviors and adverse pregnancy outcomes has been well documented. One method to alter these behaviors is through the advice of women's health care providers. Advice from providers may be particularly important in minority populations, who have higher rates of infant mortality and prematurity. This study examines racial disparities according to women's self-report of advice received from health care providers during pregnancy in four areas: tobacco use, alcohol consumption, drug use, and breast-feeding. METHODS: Health care providers' advice to 8310 White non-Hispanic and Black women was obtained from the National Maternal and Infant Health Survey. RESULTS: After controlling for sociodemographic, utilization, and medical factors, Black women were more likely to report not receiving advice from their prenatal care providers about smoking cessation and alcohol use. The difference between Blacks and Whites also approached significance for breast-feeding. No overall difference was noted in advice regarding cessation of drug use, although there was a significant interaction between race and marital status. CONCLUSIONS: These data suggest that Black women may be at greater risk for not receiving information that could reduce their chances of having an adverse pregnancy outcome.

Adolescent↗

PubMed1993

Immunohistochemical identification of trigeminal ganglion neurons that innervate the mouse cornea: relevance to intercellular spread of herpes simplex virus.

Inoculation of the scarified cornea with herpes simplex virus (type 1) leads to herpetic infection of trigeminal ganglion cells. A recent study of the susceptibility of ganglion cells revealed that there may be at least four populations of trigeminal ganglion cells that are infectable by herpes. Two classes were identified by their neuropeptide content: Substance P or calcitonin gene-related peptide. One class was identified by its affinity for a monoclonal antibody, SSEA-3. The fourth class was recognized by its common affinity for both the monoclonal antibody LD2 and for the lectin Bandeiraea simplicifolia isolectin. However, there has been no direct evidence of which types are infected directly as a result of retrograde transport from the corneal site and which may be infected by cell-to-cell spread. The aim of this study was to determine which classes of neurons, which are known to become infected with HSV after ocular inoculation, supply corneal innervation. We have identified four classes of trigeminal ganglion neurons that supply axons to the central cornea of the mouse, on the basis of their ability to transport Fluoro-Gold retrograde from axons in the central corneal epithelium and stroma. About 40% of the neurons that innervate the cornea contain Substance P or calcitonin gene-related peptide; about 60% of the neurons that innervate the cornea react with the monoclonal antibody SSEA-3. About 36% of all neurons in the whole ophthalmic division react with the LD2 or Bandeiraea simplicifolia isolectin, and Fluoro-Gold labels only 2% of them.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

A note concerning misconceptions of the general public about brain injury.

A survey performed in South Louisiana disclosed that the general population held a number of misconceptions about the sequelae of brain injury. The authors cautioned that the respondents represented a convenient sample and were representative of only a small geographic region, and challenged others to conduct similar surveys in other regions of the country. The present study represents a replication of the Gouvier et al. survey in samples of individuals residing in Western New York State and Southern Ontario, Canada. The results of the current study are consistent with those reported by Gouvier et al., namely that misconceptions about brain injury are common. The impact of these misconceptions for individuals with brain injury are discussed.

Journal Article↗

PubMed1992

Clients/patients with a principal diagnosis of affective disorder served in the inpatient, outpatient, and partial care programs of specialty mental health organizations, United States, 1986.

Of the 1.7 million persons under care on April 1, 1986 in the psychiatric inpatient, outpatient, and partial care programs of specialty mental health organizations nationwide, approximately 365,500 persons, or 22 percent, had a principal diagnosis of affective disorder. The vast majority of these persons, 84 percent, were under care in outpatient programs; 10 percent, in inpatient programs; and 6 percent, in partial care programs. Approximately 833,000, or 21 percent, of the 3.9 million persons admitted during 1986 to these same psychiatric programs had a diagnosis of affective disorder. Fifty-nine percent of persons with affective disorders were admitted to inpatient programs; 37 percent, to outpatient programs; and 4 percent, to partial care programs. Overall, most persons with affective disorders admitted to and under care in each of the three program types were female, white, and between the ages of 25 and 64. Most persons admitted to and under care in inpatient and partial care programs had a history of prior inpatient mental health care, while most persons in outpatient programs had never been treated in an inpatient psychiatric care setting. The principal source of payment used by persons with affective disorders varied by type of program setting. Blue Cross or other commercial insurance was the most common source of payment used by persons within inpatient programs, personal resources were used most often by persons under care in outpatient programs, and some type of public funds was used most often within partial care programs. Most persons with affective disorders were referred to inpatient and outpatient programs by family or friends, or were self-referrals. Most persons in partial care programs with affective disorders were referred to the program by an inpatient, outpatient, or another partial care mental health service. Services received by persons with affective disorders also varied by program setting. In general, drug and individual therapy were the leading types of treatment provided in inpatient programs. Individual therapy was the leading type of treatment provided, followed by drug therapy, in outpatient programs. Within partial care programs, no single type of treatment predominated.

Adult↗

PubMed1991

Solid-phase extraction of pesticides from water: possible interferences from dissolved organic material.

A multiresidue analysis for trifluralin, simazine, atrazine, propazine, diazinon, parathion-methyl, alachlor, malathion, parathion, chlorpyrifos, pendimethalin, methidathion, and DEF in water that utilizes liquid-solid extraction (LSE) with octadecyl-bonded silica cartridges (C18BSCs) followed by gas chromatography/mass spectrometric analysis was developed. Recoveries of most pesticides were greater than 80% with C18BSCs from fortified water at concentration levels from about 1 to 500 ppb. Recoveries with C18BSCs, from an optically adjusted humic acid solution (10 ppm dissolved organic carbon) made to simulate a natural water with a high dissolved organic content, ranged from 29 to 153% and in general were lower than recoveries obtained from pure water. 14C-Labeled diazinon and parathion were recovered from the humic acid solution at levels of 57 and 68%, respectively, with C18BSCs; the remainder of the labeled pesticides was found in the cartridge eluents. Partition coefficients with human acid were calculated based on recovery of 14C-labeled pesticides from the C18BSCs.

Indicators and Reagents↗

PubMed1990

Stylized chromosome images.

Stylized chromosome images 1) serve as a format to test effects of preprocessing algorithms used in automated karyotyping; 2) enhance the ability of humans to perform quantitative analysis of chromosomal aberrations; 3) provide an alternative format for karyotype hard copies produced by automated systems. Stylized chromosomes are two-dimensional computer-generated images based on information extracted from one-dimensional width and density profiles. These profiles correspond to what cytogeneticists observe through the microscope as the shape and banding patterns of stained chromosomes. Stylized presentation sharpens chromosome band boundaries and perimeters, reduces "noise," and enhances gray level variations, which are difficult to distinguish by humans on photographic or computer generated karyotypes. Karyotyping accuracy using stylized images was used to detect difficult areas for automated chromosome identification. Landmark bands sufficient to classify chromosomes were identified; shapes of chromosomes reflected in width profiles were said to aid classification. A two-step automated karyotyping strategy proposed is: 1) classify chromosomes by landmarks, minimum information needed for identification; 2) subsequently employ the full banding pattern with maximum resolution to detect aberrations. Stylized images of abnormal chromosomes have potential for testing hypothesis regarding breakpoints and quantitative analysis, but improvements are needed in homologue normalization and definition of termini of chromosomes.

Algorithms↗

PubMed1989

Murder and assault arrests of White House cases: clinical and demographic correlates of violence subsequent to civil commitment.

The authors studied arrest records and clinical data on 217 persons formerly hospitalized as "White House Cases" because they were psychotically preoccupied with prominent political figures. Prior arrest for violent crime was the variable most strongly associated with arrest for violent crime after hospital discharge. Male gender and a history of weapons possession were also correlated with future violence. For those with prior violent crime arrests, hospital incidents requiring seclusion were also associated with later violence. For those without prior arrests, subsequent violence was associated with threats, living outside Washington, and command hallucinations. For those previously arrested for nonviolent crimes, only persecutory delusions were associated with later violence.

Commitment of Persons with Psychiatric Disorders↗

PubMed1988

Violent crime arrests and paranoid schizophrenia: the White House case studies.

We have previously reported on typically paranoid schizophrenic patients who attempted to see the President or other prominent American political figures based on hallucinations or delusional beliefs. By obtaining arrest records on these White House Cases (WHCs), we were able to determine which individuals had murder or assault arrests before and/or after their WHC hospitalizations. During the 9-12 years following discharge, 31 of the 217 male WHCs (for whom adequate clinical records were available) had murder or assault arrests. Demographic characteristics such as prior violent crime arrest and male gender proved to be much better predictors of future violence than clinical symptom, history, or behavior items. Hospital incidents requiring seclusion and a history of weapons possession were both associated with later violence in WHCs with prior violent crime arrests, while certain clinical symptoms (e.g., persecutory delusions and command hallucinations) may be linked to future violence in WHCs without prior violent crime arrests. These data need replication in other patient samples.

Chronic Disease↗