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Biomedical subjects

M M Green

Publications and source records attributed to M M Green.

At least 37 records · Page 2Linked to original sources
PubMed1996

Hemoglobin S/hemoglobin Osler: a case with 3 beta globin chains. DNA sequence (AAT) proves that Hb Osler is beta 145 Tyr-->Asn.

A 13-year-old African-American female with erythrocytosis and three different beta globins on electrophoresis beta A, beta S, and beta Osler, raised the possibility that one chromosome 11 might contain a duplicated beta globin gene, since there are normally only 2 beta globin genes. DNA sequence analysis showed GTG at codon 6 in exon 1, corresponding to Hb S and AAT at codon 145 in exon 3, indicating a substitution of Asn for Tyr. Thus, Hb Osler undergoes spontaneous post-translational deamidation, beta 145 Asn-->beta 145 Asp. Unmodified Hb Osler (Asn) co-migrates with Hb A on electrophoresis and co-elutes with Hb A on HPLC; therefore it has not been identified previously. All previous studies have incorrectly identified the mutation as being beta 145 (HC 2) Tyr-->Asp.

Adolescent↗
PubMed1996

Hb Cook [beta 132(H10)Lys-->Thr]: a new hemoglobin variant in a southeast Asian family.

Approximately 700 hemoglobin variants have been reported, causing a variety of clinical manifestations, with the majority being clinically silent. We report a new hemoglobin variant, Hb Cook, that was found in combination with Hb E in a child of Thai origin. DNA sequencing of the beta-globin gene showed that the mutation is AAA-->ACA in codon 132, corresponding to beta 132 (H10)Lys-->Thr.

Asia, Southeastern↗
PubMed1995

Molecular characterization of spontaneous mutations at the scarlet locus of Drosophila melanogaster.

Six spontaneous mutations of the scarlet (st) locus of Drosophila melanogaster have been studied at the molecular level. Two of the mutants (st1 and stsp) arose in laboratory populations, while the other four (stcob, stct89, stdct and stdv) were isolated from natural populations. In five of these there is a DNA insertion within the st region and in four cases the insertion has been identified as being a transposable element; these include the retrotransposons 412 and B104/roo, and also jockey a member of the LINE family. In the other case (stdct), the insertion appears to consist of partially duplicated st sequences. In two of the mutants (st1 and stdv) the same transposable element (412) has inserted in the same orientation at exactly the same site within the st gene. The transposable element insertions are found in intron and exon regions of the st gene and also in the putative upstream regulatory region; insertions located in introns or exons result in the production of truncated st transcripts. The results show that the same types of transposable elements that cause spontaneous mutation in laboratory stocks of D. melanogaster also cause mutation in the wild.

ATP-Binding Cassette Transporters↗
PubMed1995

The silver gene of Drosophila melanogaster encodes multiple carboxypeptidases similar to mammalian prohormone-processing enzymes.

The silver (svr) gene of Drosophila melanogaster is required for viability, and severe mutant alleles result in death prior to eclosion. Adult flies homozygous or hemizygous for weaker alleles display several visible phenotypes, including cuticular structures that are pale and silvery in color due to reduced melanization. We have identified and cloned the DNA encoding the svr gene and determined the sequence of several partially overlapping cDNAs derived from svr mRNAs. The predicted amino acid sequence of the polypeptides encoded by these cDNAs indicates that the silver proteins are members of the family of preprotein-processing carboxypeptidases that includes the human carboxypeptidases E, M, and N. One class of svr mRNAs is alternatively spliced to encode at least two polyproteins, each of which is composed of two carboxypeptidase domains.

Amino Acid Sequence↗
PubMed1995

The molecular analysis of brown eye color mutations isolated from geographically discrete populations of Drosophila melanogaster.

A large proportion of spontaneous mutations in Drosophila melanogaster strains of laboratory origin are associated with insertions of mobile DNA elements. As a first step toward determining whether spontaneous laboratory mutations are predictive for mutational events occurring in the wild, recessive brown (bw) eye color mutants were isolated. By inbreeding the progeny of wild-caught Drosophila melanogaster females, bw mutations were isolated from seven separate geographic sites distributed among Japan, California. Siberia and Hungary. Among a total of 14 mutations studied, no case of transposon mutagenesis was found. At least 4 mutations are associated with small deletions in the bw gene. The remainder are inseparable from wild-type bw by Southern analysis and are presumed to be basepair changes or very small indels. Although only two spontaneous bw mutants of laboratory origin have been analyzed molecularly, one is a mobile element insertion.

Alleles↗
PubMed1995

An intragenic tandem duplication of genomic DNA is responsible for the f3N mutation of Drosophila melanogaster.

Among the numerous X chromosome-linked forked bristle (f) mutations described in Drosophila melanogaster, one designated f3N exhibits the unusual property of reverting spontaneously to wild type at an inordinate frequency, a frequency that can be increased with x-ray irradiation. In contrast to the f mutants described thus far, all of which are associated with the insertion of mobile DNA elements, f3N is associated with an intragenic duplication of 2.8 kb of genomic DNA that resolves to the normal sequence when reversions occur. Consideration is given to intrachromosomal recombination as the mechanism of reversion and truncation of the forked protein as a cause for the mutant phenotype.

Amino Acid Sequence↗
PubMed1995

White as a reporter gene to detect transcriptional silencers specifying position-specific gene expression during Drosophila melanogaster eye development.

The white+ gene was used as a reporter to detect transcriptional silencer activity in the Drosophila genome. Changes in the spatial expression pattern of white were scored in the adult eye as nonuniform patterns of pigmentation. Thirty-six independent P[lacW] transposant lines were collected. These represent 12 distinct pigmentation patterns and probably 21 loci. The spatial pigmentation pattern is due to cis-acting suppression of white+ expression, and the suppression probably depends on cell position rather than cell type. The mechanism of suppression differs from inactivation by heterochromatin. In addition, activation of lacZ in P[lacW] occurs also in specific patterns in imaginal discs and embryos in many of the lines. The expression patterns of white+ and lacZ may reflect the activity of regulatory elements belonging to an endogenous gene near each P[lacW] insertion site. We speculate that these putative POSE (position-specific expression) genes may have a role in pattern formation of the eye as well as other imaginal structures. Three of the loci identified are optomotor-blind, engrailed and invected. teashirt is also implicated as a candidate gene. We propose that this "silencer trap"' may be an efficient way of identifying genes involved in imaginal pattern formation.

ATP-Binding Cassette Transporters↗
PubMed1993

Undiagnosed post-traumatic stress disorder following motor vehicle accidents.

OBJECTIVES: To determine the pattern of emergence of post-traumatic stress disorder (PTSD) among motor vehicle accident victims and to examine the influence of PTSD on subsequent levels of disability. DESIGN: A longitudinal study of motor vehicle accident victims one month and 18 months after the accident. SUBJECTS: Twenty-four motor vehicle accident victims admitted by the trauma team at the Royal Adelaide Hospital. A 52% response rate was achieved. MAIN OUTCOME MEASURES: Post-traumatic stress disorder as diagnosed by the Diagnostic Interview Schedule and disability as measured with the Sickness Impact Profile. RESULTS: Eighteen months after their accidents, six of the 24 subjects had clinically significant PTSD and one was considered borderline. None had been previously diagnosed or treated. The group with PTSD had higher scores on all measures of psychological distress one month after the accident and were more likely to use immature psychological defences. There was no association between physical outcome (measured with the modified Glasgow Outcome Scale) at six months and subsequent diagnosis of PTSD. However, the group with PTSD had higher levels of disability on assessment with the Sickness Impact Profile, particularly in the domain of social functioning. The results suggest PTSD was associated with work-related dysfunction equal to that associated with severe physical handicap. CONCLUSION: The data from this pilot study suggest that PTSD after motor vehicle accidents is an important cause of disability, which may also become the focus for damages in litigation. Thus, there is a need for further investigation of the early patterns of distress and to design preventive programs for victims of road accidents.

Accidents, Traffic↗
PubMed1991

Mutations in the su(s) gene affect RNA processing in Drosophila melanogaster.

We have studied the effect of mutations in the suppressor of sable [su(s)] gene on P element-induced yellow alleles. Two independent mutations tested, y76d28 and y1#7, contain a 1.1-kilobase (kb) P element inserted in the 5' transcribed untranslated portion of the yellow gene. Sequences responsible for the y1#7 mutation are inserted in the same transcriptional orientation as yellow and cannot be processed by splicing, and this mutation is not suppressed by su(s) mutations. P element sequences are located in a transcriptional orientation opposite to that of the yellow gene in y76d28; these sequences can be spliced from a composite P element-yellow mRNA, resulting in low accumulation of a functional 1.9-kb yellow transcript. The levels of both the putative precursor P element-yellow RNA and the 1.9-kb yellow transcript increase in y76d28 su(s) flies, suggesting that mutations in su(s) do not affect the efficiency of splicing of the P element sequences. Analysis of y76d28 cDNAs isolated from flies carrying a wild-type or mutant su(s) gene demonstrates that the choice of splice junctions to process P element sequences is unchanged in these different backgrounds, suggesting that mutations in su(s) do not affect the selection of donor and acceptor splice sites. We propose that the su(s) protein functions to control the stability of unprocessed RNA during the splicing reaction.

Alleles↗
PubMed1991

Acute pelvic inflammatory disease after surgical sterilization.

STUDY OBJECTIVE: Physicians are very cognizant of the possibility of pregnancy after surgical sterilization, but the potential for acute pelvic inflammatory disease (PID) is thought to be rare. This study was undertaken to determine if upper tract PID occurred more frequently than previously reported in patients remote from surgical sterilization. DESIGN: Retrospective review of hospitalized patients with the primary discharge diagnosis of PID. SETTING: Urban, university hospital. PARTICIPANTS: Three hundred sixty-four hospitalized patients with the primary discharge diagnosis of PID over a six-year study period. MEASUREMENTS AND MAIN RESULTS: Patients' age; gynecologic histories and diagnoses; and laboratory, clinical, and surgical findings were noted. Twenty-three cases of acute PID were identified in 21 patients previously sterilized (6%). Nine of the 23 cases had systemic toxicity warranting surgical evaluation; 18 of the 23 cases were admitted from the emergency department. Mean statistical characteristics of the study group were age, 27.3 +/- 0.8 (SE) years; time interval from sterilization, 49.8 +/- 7.4 months; WBC 15,000 +/- 1,200; and temperature, 38.0 +/- 0.2 C. CONCLUSION: We conclude that acute PID may occur more frequently than previously reported in patients with prior surgical sterilization. An increased awareness of this entity is warranted.

Acute Disease↗
PubMed1991

Cloning and direct sequencing from lambda cDNA libraries using the polymerase chain reaction: suppressin and the vasopressin receptor as models.

A strategy using the polymerase chain reaction (PCR) to screen a lambda gt11 pituitary cDNA library for cDNAs encoding suppressin, a putative anti-proliferative protein, and a putative vasopressin receptor is described. The use of this technique will facilitate the demonstration of e.g. the presence of "neuropeptide receptors" on cells of the lymphoid system, confirming the concept of "shared ligands and receptors" by the neuroendocrine and the immune system. Neither of the genes encoding the proteins of the present study have previously been cloned. The PCR-screening procedure requires sequence information from the gene of interest which permits the generation of complementary primers. These primers are then used in combination with lambda phage primers complementary to regions flanking the cloning site in a PCR to amplify cDNAs derived from the gene of interest. This novel screening procedure yields cDNA related to the gene of interest, including the largest clone present in the library. To confirm the utility of this technique for cDNA libraries, the library was also screened using traditional cDNA hybridization techniques. The largest clone obtained by screening the cDNA library with PCR was the same as that obtained by the conventional technique. Thus, the results of these studies show that the PCR method can be used instead of more conventional means to screen cDNA libraries. Lastly, we describe a protocol for directly sequencing PCR-amplified DNA using the same primers that are used for amplification. The combined use of these two strategies permits cloning and sequencing of cDNAs from lambda cDNA libraries in a fraction of the time required using traditional screening techniques, but with identical results.

Animals↗
PubMed1991

Larvicidal activity of Tagetes minuta (marigold) toward Aedes aegypti.

The steam distilled oils of 3 species of marigold, Tagetes patula, T. erecta and T. minuta, were tested for larvicidal activity toward third instar Aedes aegypti; activity at 10 ppm was demonstrated only for T. minuta. The larvicidal property of the whole oil dispersed in water persisted for at least 9 days. The terpene, ocimenone, which is a part of the whole oil, was found to be larvicidal only at a higher concentration than the whole oil and to lose its activity within 24 h after dispersal in water. These results suggest a potential utilization of oil of T. minuta or its components for the control of Ae. aegypti and other species of mosquitoes.

Aedes↗
PubMed1990

Tissue-specific transcriptional enhancers may act in trans on the gene located in the homologous chromosome: the molecular basis of transvection in Drosophila.

The y2 mutation resulted from the insertion of the gypsy element into the X-linked yellow locus of Drosophila melanogaster. As a consequence of this insertion, transcriptional enhancers that control the expression of the yellow gene in the wings and body cuticle of adult flies are unable to act on the yellow promoter, resulting in a tissue-specific phenotype characterized by mutant coloration in these structures. Some yellow null alleles (yn) are able to complement the y2 phenotype giving rise to near wild type y2/yn females. The molecular structure of the yellow locus in complementing and noncomplementing mutations was determined by cloning and sequencing the various alleles examined. From the information obtained in these studies, we propose a model suggesting that the complementing wild type phenotype of y2/yn flies might be due to the ability of functional wing and body cuticle transcriptional enhancers located in the yn locus to act in trans on the promoter of the yellow gene found in the y2-containing chromosome. Furthermore, this transactivation is abolished by the presence of an intact promoter in cis, suggesting that promoter competition between the yellow genes located on each homolog precludes the activation in trans by transcriptional enhancers in favour of cis effects on their own promoter.

Alleles↗
PubMed1990

Immunomodulatory characteristics of a novel antiproliferative protein, suppressin.

We investigated the immunoregulatory properties of a recently described inhibitor of lymphocyte proliferation, suppressin (SPN). It was determined that preincubation of murine leukocytes with SPN enhances natural killer cell (NK) activity. In addition, SPN potentiates interferon-gamma (IFN-gamma) augmentation of NK activity. Furthermore, preincubation of murine leukocytes with SPN induces the production of IFN-alpha/beta. The IFN-alpha/beta produced is active in NK assays as well as vesicular stomatitis virus neutralization assays. In vivo, SPN increases the time of survival of C57BL/6 mice injected with EL-4 lymphoma cells. Interestingly, SPN inhibits immunoglobulin (IgA, IgG, and IgM) production in response to the mitogen, concanavalin A in a dose-dependent manner. Collectively, the above data indicate SPN may have numerous applications in clinical science including tumor surveillance and autoimmune diseases such as arthritis.

Animals↗