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Biomedical subjects

J Greenberg

Publications and source records attributed to J Greenberg.

At least 19 recordsLinked to original sources
PubMed1995

An eighth locus for autosomal dominant retinitis pigmentosa is linked to chromosome 17q.

Retinitis pigmentosa is one of the most common causes of severe visual handicap in middle to late life. Prior to this report, seven loci had previously been mapped for the autosomal dominant form of this disorder (adRP). We now report the identification of a novel adRP locus on chromosome 17q. To map the new locus, we performed linkage analysis with microsatellite markers in a large South African kindred. After exclusion of 13 RP candidate gene loci (including rhodopsin and peripherin-RDS), we obtained significant positive lod scores at zero recombination fraction (theta = 0) for D17S808 (Z = 4.63) and D17S807 (Z = 5.69). Multipoint analysis gave a maximum lod score of 8.28 between these two markers. From haplotype analysis, the disease locus lies in the interval between markers D17S809 and D17S942. Three candidate genes for retinal dystrophies map to this chromosomal region and these genes are currently being investigated for possible involvement with adRP in this family.

Adult↗
PubMed1995

Volatile organic compounds in the breath of patients with schizophrenia.

AIMS: To analyse the breath of patients with schizophrenia for the presence of abnormal volatile organic compounds. METHODS: A case comparison study was performed in two community hospitals in Staten Island, New York. Twenty five patients with schizophrenia, 26 patients with other psychiatric disorders, and 38 normal controls were studied. Alveolar breath samples were collected from all participants, and volatile organic compounds in the breath were assayed by gas chromatography with mass spectroscopy. Differences in the distribution of volatile organic compounds between the three groups were compared by computerised pattern recognition analysis. RESULTS: Forty eight different volatile organic compounds were observed in the breath samples. Three separate pattern recognition methods indicated an increased differentiation capability between the patients with schizophrenia and the other subjects. Pattern recognition category classification models using 11 of these volatile organic compounds identified the patients with schizophrenia with a sensitivity of 80.0% and a specificity of 61.9%. Volatile organic compounds in breath were not significantly affected by drug therapy, age, sex, smoking, diet, or race. CONCLUSIONS: Microanalysis of volatile organic compounds in breath combined with pattern recognition analysis of data may provide a new approach to the diagnosis and understanding of schizophrenia. The physiological basis of these findings is still speculative.

Breath Tests↗
PubMed1995

Psychoanalytic technique and the interactive matrix.

In this paper the concept of an "interactive matrix" is introduced. The interactive matrix is shaped, from moment to moment in every treatment, by the personal characteristics of the analysand and of the analyst. These include the beliefs, commitments, hopes, fears, needs, and wishes of both participants. It is only within the context of the interactive matrix that the events of an analysis acquire their meaning. The implications of this perspective for analytic technique are explored and illustrated with a clinical example.

Female↗
PubMed1994

The type I macrophage scavenger receptor binds to gram-positive bacteria and recognizes lipoteichoic acid.

Macrophage scavenger receptors exhibit unusually broad binding specificity for polyanionic ligands and have been implicated in atherosclerosis and various host defense functions. Using a radiolabeled, secreted form of the type I bovine macrophage scavenger receptor in an in vitro binding assay, we have found that this receptor binds to intact Gram-positive bacteria, including Streptococcus pyogenes, Streptococcus agalactiae, Staphylococcus aureus, Enterococcus hirae, and Listeria monocytogenes. Competition binding studies using purified lipoteichoic acid, an anionic polymer expressed on the surface of most Gram-positive bacteria, show that lipoteichoic acids are scavenger receptor ligands and probably mediate binding of the receptor to Gram-positive bacteria. Lipoteichoic acids, for which no host cell receptors have previously been identified, are implicated in the pathogenesis of septic shock due to Gram-positive bacteria. Scavenger receptors may participate in host defense by clearing lipoteichoic acid and/or intact bacteria from tissues and the circulation during Gram-positive sepsis. Since scavenger receptors have been previously shown to bind to and facilitate bloodstream clearance of Gram-negative bacterial endotoxin (lipopolysaccharide), these receptors may provide a general mechanism for macrophage recognition and internalization of pathogens and their cell surface components.

Animals↗
PubMed1994

Desmethylimipramine, a potent inhibitor of synaptosomal norepinephrine uptake, has diverse effects on thyroid hormone processing in rat brain. II. Effect on in vivo 5'-deiodination of [125I]thyroxine.

We have studied the effects of desmethylimipramine (DMI), a tricyclic antidepressant, on thyroid hormone (TH) handling in rat brain in an effort to discover a pharmacological basis for reported interactions between TH, affective disorders and psychotropic drugs. An acute dose of DMI has been used in order to determine the primary effects of the drug in brain without perturbations from secondary effects. Recently we have reported that a single dose of DMI significantly decreases brain uptake of both [125I]thyroxine (T4) and [125I]3,3',5-triiodothyronine (T3) across the spectrum of thyroid states from hypothyroid (HYPO) to euthyroid (EU) to T4-induced hyperthyroid (HYPER). To investigate further the effects of DMI on brain processing of TH, we have measured effects of the drug on in vivo rates of T4 to T3 conversion in a series of experiments in which DMI (25 mg/kg) was given to HYPO, EU and HYPER male rats in conjunction with i.v. [125I]T4. Decreased in vivo conversion ratios (T3/T4 ratios) suggest that acute DMI treatment causes a significant decrease in 5'-deiodinase activity in balance of brain (but not cerebellum) in all DMI treated rats as compared to their saline treated controls (ANOVA, P < 0.0001). For assurance that reduced T3/T4 in DMI treated rat brain is not the result of DMI enhancement of 5-deiodination of T3 or T4, the effect of DMI on concentrations of labeled I-, rT3, and T2 (3,3'- and 3',5'-) was also observed. In no case was there a significant increase in any metabolite in DMI treated rats for any tissue studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

Role of consciousness and accessibility of death-related thoughts in mortality salience effects.

On the basis of terror management theory, research has shown that subtle mortality salience inductions engender increased prejudice, nationalism, and intergroup bias. Study 1 replicated this effect (increased preference for a pro-U.S. author over an anti-U.S. author) and found weaker effects when Ss are led to think more deeply about mortality or about the death of a loved one. Study 2 showed that this effect is not produced by thoughts of non-death-related aversive events. Studies 2 and 3 demonstrated that this effect occurs only if Ss are distracted from mortality salience before assessment of its effects. Study 4 revealed that although the accessibility of death-related thoughts does not increase immediately after mortality salience, it does increase after Ss are distracted from mortality salience. These findings suggest that mortality salience effects are unique to thoughts of death and occur primarily when such thoughts are highly accessible but outside of consciousness.

Affect↗
PubMed1994

Using socially fair treatment to promote acceptance of a work site smoking ban.

Announcements of a work site smoking ban were made to 732 clerical workers. The presentations differed in the amount of information given about the need for the ban and the degree of interpersonal sensitivity shown over the personal impact of the ban. Immediately after the announcement, questionnaires were completed to assess participants' acceptance of the ban. High amounts of information thoroughness and of social sensitivity, given separately, enhanced acceptance of the ban, but their combined effects were even greater. Although heavy smokers were least accepting of the ban, they showed the greatest incremental gain in acceptance after exposure to thorough information presented in a highly sensitive manner. By contrast, nonsmokers' acceptance of the ban was uniformly unaffected by the way it was presented to them. Regardless of how much they smoked, all participants recognized the procedural fairness associated with giving thorough information in a socially sensitive manner.

Adult↗
PubMed1994

DNA haplotype analysis of Huntington disease reveals clues to the origins and mechanisms of CAG expansion and reasons for geographic variations of prevalence.

This study of allelic association using three intra- and two extragenic markers within 150 kb of the Huntington disease (HD) mutation has provided evidence for linkage disequilibrium for four of five markers. Haplotype analysis of 67 HD families using markers in strong linkage disequilibrium with HD identified two haplotypes underlying 77.6% of HD chromosomes. Normal chromosomes with these two haplotypes had a mean number of CAG repeats significantly larger than and an altered distribution of CAG repeats compared with other normal chromosomes. Furthermore, haplotype analysis of five new mutation families reveals that HD has arisen on these same two chromosomal haplotypes. These findings suggest that HD arises more frequently on chromosomes with specific DNA haplotypes and higher CAG repeat lengths. We then studied CAG and CCG repeat lengths in the HD gene on 896 control chromosomes from different ancestries to determine whether the markedly reduced frequency of HD in Finland, Japan, China and African Blacks is associated with an altered frequency of DNA haplotypes and subsequently lower CAG lengths on control chromosomes compared to populations of Western European descent. The results show a highly significant inverse relationship between CAG and CCG repeat lengths. In populations with lowered prevalence rates of HD, CAG repeat lengths are smaller and the distribution of CCG alleles is markedly different from Western European populations. These findings suggest that, in addition to European emigration, new mutations make a contribution to geographical variation of prevalence rates and is consistent with a multistep model of HD developing from normal chromosomes with higher CAG repeat lengths.

Africa↗
PubMed1994

A new locus for autosomal dominant retinitis pigmentosa on the short arm of chromosome 17.

Retinitis pigmentosa (RP) is a group of genetically and clinically heterogeneous retinopathies, some of which have been shown to result from mutations in two different known retinal genes, rhodopsin (3q) and peripherin-rds (6p). Three additional anonymous loci at 7p, 7q and pericentric 8 have been implicated by linkage studies. There are still, however, a few families in which all known loci have been excluded. In this report we present data indicating a location, on the short arm of chromosome 17, for the autosomal dominant RP (ADRP) locus in a large South African (SA) family of British ancestry. Positive two-point lod scores have been obtained for nine markers (D17S938, Z = 5.43; D17S796, Z = 4.82; D17S849, Z = 3.6; D17S786, Z = 3.55; TP53, Z = 3.55; D17S578, Z = 3.29; D17S960, Z = 3.16; D17S926, Z = 1.51; D17S804, Z = 0.47 all at theta = 0.10 except D17S804 and D17S926, theta = 0.20). These data provide definitive evidence for the localization of an ADRP gene on chromosome 17p. The human recoverin gene has been localized to 17p13.1 and was consequently a prime candidate for ADRP in the family studied. However, mutation screening of the three exons of this gene failed to produce any evidence of recoverin being the gene involved in the pathogenesis of ADRP in this SA family.

Calcium-Binding Proteins↗
PubMed1994

Metabolic and environmental origins of volatile organic compounds in breath.

Although more than 200 volatile organic compounds (VOCs) have been identified in human alveolar breath, their origins are still mostly unknown. An attempt was made to determine whether the major VOCs in breath were derived from inside or outside the body--that is, were they products of metabolism or contaminants from the environment? The concentrations were measured of the 24 most abundant VOCs in the alveolar breath of 12 normal volunteers and also in the air they inspired. The polarity of the mean alveolar gradient (concentration in breath minus concentration in inspired air) was positive in 15 VOCs and negative in nine. The mean alveolar gradient varied from strongly positive (for example, 2,3,3-trimethylpentane), consistent with a metabolite manufactured in the body, to strongly negative (for example, isoprene), consistent with ingestion of an air pollutant which was then catabolised in vivo or excreted via an extra-pulmonary pathway.

Breath Tests↗
PubMed1994

Alveolar gradient of pentane in normal human breath.

Previous studies have raised the question of whether pentane is a normal constituent of human breath, since its concentrations in inspired room air and expired breath are often similar. Using a highly sensitive assay for volatile organic compounds, we studied 37 normal subjects in order to determine the alveolar gradient of pentane in their breath (i.e. concentration in alveolar breath minus concentration in the inspired air). The chemical identity of pentane was confirmed by mass spectroscopy. The alveolar gradient of pentane was zero +/- 0.175 nmol/l in 54.1% of subjects, and distributed in an approximately bell-shaped curve. Determination of the alveolar gradient divided the normal subjects into three groups: the "passive equilibrators" who did not appear to excrete pentane in the breath (the majority), "metabolizers" who actively catabolized inhaled pentane, and "manufacturers" who excreted more pentane than they inhaled.

Breath Tests↗
PubMed1994

Genetic mapping of retinitis pigmentosa--implications for South African patients.

The term 'retinitis pigmentosa' (RP) encompasses a group of hereditary degenerative disorders of the retina, which are both genetically and clinically heterogeneous. The finding of molecular markers for certain forms of RP potentially allows for presymptomatic and prenatal diagnosis of a proportion of RP families. These developments and their implications for affected South African families are highlighted in this article.

Chromosome Mapping↗
PubMed1994

Computed tomography or endoscopic ultrasonography in preoperative staging of gastric and esophageal tumors.

BACKGROUND: Accurate preoperative staging of tumors of the esophagus and stomach is important in selecting treatment and determining prognosis. To date, no exact preoperative test has been useful in assessing stage of these tumors. Until recently, computed tomographic (CT) scanning has been the most frequently used examination to predict operative findings. Endoscopic ultrasonography (EUS) is a relatively new modality used by some centers to assess extramural anatomy of tumors in these two locations. METHODS: We described 28 patients with tumors involving the esophagus and gastroesophageal junction, and the stomach, who underwent both EUS and CT before surgical exploration. We compared these two tests with the final pathologic interpretation and paid particular attention to presence of lymph nodes and wall penetration by primary tumor. RESULTS: For wall penetration by an esophageal-gastroesophageal junction carcinoma, EUS was 85% accurate versus 15% for CT. For absence of nodal spread by these tumors, EUS was 100% accurate versus 67% for CT. In the presence of nodal spread EUS was 60% accurate versus 50% for CT. For wall penetration by a gastric carcinoma, EUS was 71% accurate versus 0% for CT. In the absence of nodal spread EUS and CT were both 100% accurate. In the presence of nodal spread EUS was 50% accurate versus 25% for CT. CONCLUSIONS: EUS is more accurate than CT in the preoperative staging of upper gastrointestinal malignancies.

Aged↗
PubMed1994

Locus heterogeneity for Waardenburg syndrome is predictive of clinical subtypes.

Waardenburg syndrome (WS) is a dominantly inherited and clinically variable syndrome of deafness, pigmentary changes, and distinctive facial features. Clinically, WS type I (WS1) is differentiated from WS type II (WS2) by the high frequency of dystopia canthorum in the family. In some families, WS is caused by mutations in the PAX3 gene on chromosome 2q. We have typed microsatellite markers within and flanking PAX3 in 41 WS1 kindreds and 26 WS2 kindreds in order to estimate the proportion of families with probable mutations in PAX3 and to study the relationship between phenotypic and genotypic heterogeneity. Evaluation of heterogeneity in location scores obtained by multilocus analysis indicated that WS is linked to PAX3 in 60% of all WS families and in 100% of WS1 families. None of the WS2 families were linked. In those families in which equivocal lod scores (between -2 and +1) were found, PAX3 mutations have been identified in 5 of the 15 WS1 families but in none of the 4 WS2 families. Although preliminary studies do not suggest any association between the phenotype and the molecular pathology in 20 families with known PAX3 mutations and in four patients with chromosomal abnormalities in the vicinity of PAX3, the presence of dystopia in multiple family members is a reliable indicator for identifying families likely to have a defect in PAX3.

Chromosome Mapping↗