PubMed Health⌕ Search

Biomedical subjects

M Graham

Publications and source records attributed to M Graham.

At least 73 records · Page 4Linked to original sources
PubMed1988

Ultrasound screening for clinically occult abdominal aortic aneurysm.

In a review of the records of 74 patients who had undergone repair of an abdominal aortic aneurysm at a community hospital between 1977 and 1983 we found that the aneurysm had been undiagnosed before rupture in 35%; these patients had an operative death rate of 50%, whereas elective repair carried a death rate of 4%. The characteristic patient was an obese man over the age of 55 years with hypertension, coronary artery disease, cerebrovascular disease or peripheral vascular disease. Ultrasound examination was performed in 45 patients with these characteristics, and six aneurysms were diagnosed. Either surgery or computed tomography confirmed the diagnosis. The rate of false-negative results was estimated by review of the charts of 100 men over the age of 55 years who had undergone abdominal ultrasonography for other indications: no undetected aneurysms were discovered over 3 years of follow-up. Routine screening in this high-risk group would improve the rate of diagnosis of this potentially fatal condition before rupture and offer the patient the lower mortality rate associated with elective surgery.

Aged↗
PubMed1988

Nevus cell aggregates in the placenta. A histochemical and electron microscopic study.

This is a report of the histochemical and ultrastructural analysis of nevus cell aggregates in the placenta from a neonate with a giant pigmented nevus. Although the distinction between aberrant migration of neural crest elements and blood-borne metastasis from the giant pigmented nevus is not readily resolved, the authors favor the former as an explanation of this unusual placental lesion.

Biopsy↗
PubMed1988

The evolution and outcome of cavitating periventricular leukomalacia in infancy. A study of 46 cases.

Forty six infants with the ultrasonic diagnosis of cavitating periventricular leukomalacia (CPVL) have been reviewed. Follow up examination results allow correlation between the ultrasound appearances and subsequent neurodevelopmental and neurological deficits. The highest incidence of this condition was found in infants at and below 27 weeks gestation, and occurred in 15% of very premature infants surviving 14 days or more. Cavities developed 15 days after the onset of periventricular echodensity (median time). Ventricular dilatation occurred in 24% of the infants who developed cavities. Follow up information was available in 27 infants and 18 of these (67%) had significant neurodevelopmental handicap. The location of echolucent cavities were described as involving anterior, middle or posterior cerebral zones or any combination of these. Cerebral palsy was closely related to the presence of cavities, but there was little association between cavities and developmental delay. Four factors were found to predict cerebral palsy: cavities within the occipital zone, the involvement of multiple regions of the brain, lesions greater than 1 cm in diameter and cavities associated with subcortical leukomalacia. Lesions confined to the anterior or middle zones were unlikely to be associated with significant handicap. The presence of cavities per se was not associated with a higher incidence of severe developmental delay.

Cerebral Palsy↗
PubMed1988

Non-Hodgkin's lymphomas.

The non-Hodgkin's lymphomas are a group of diseases for which substantial progress has been made in understanding tumor biology and effectiveness of treatment during the last few years. These advances may provide insight into the development of neoplasms because of recognized association of lymphomas with viral infections and immunodeficiency. The prognosis for patients with non-Hodgkin's lymphomas continues to improve. As a result, current studies on treatment of lymphomas in certain favorable stages have concentrated on reducing the intensity of therapy. For patients with advanced disease, further improvements in treatment are being sought.

Adolescent↗
PubMed1987

Prediction of cerebral palsy in very low birthweight infants: prospective ultrasound study.

The value of regular cerebral ultrasound scanning in predicting cerebral palsy (CP) was assessed in very low birthweight infants. The infants were scanned before discharge, and their vision and hearing were assessed at age 9 months and neurodevelopment was assessed at 18 months. Ultrasound abnormalities, defined before the study, were periventricular haemorrhage (PVH), "prolonged flare" (echodensity persisting in the periventricular white-matter for more than 2 weeks without cavitating), and cystic periventricular leukomalacia (PVL). The incidence of these three conditions in surviving infants was 49%, 15%, and 8%, respectively. 158 infants survived to be discharged from hospital and 156 had neurodevelopmental assessment at 18 months of corrected age. All infants with PVH alone and confined to the lateral ventricles were normal at follow-up. The presence of cysts accurately predicted abnormal outcome (94%) and was highly specific (96%). Prolonged flare predicted adverse outcome but the accuracy (79%) was less good than for cystic PVL. 12 infants had CP, and 10 of these had ultrasound evidence of PVL. 8 of the 13 infants with cysts had spastic CP. 4 of these were walking independently and had mild CP. No infant with ultrasound evidence of a single cyst or with cysts confined to the frontal region or centrum semiovale had severe CP. Cysts involving the periventricular white-matter in the occipital region were associated with a poor prognosis. Echolucent cystic lesions detected by ultrasound in the neonatal period accurately predict adverse outcome, and if multiple and present in the occipital region, confer a very high risk of severe CP.

Cerebral Hemorrhage↗
PubMed1987

The indirect flight muscle of Drosophila accumulates a unique myosin alkali light chain isoform.

Mapping of the 5' and 3' ends of the Drosophila myosin alkali light chain (MLC-ALK) mRNA by S1 nuclease and primer extension assays has shown that the primary transcripts are identical irrespective of the time in development that the RNA was prepared. As shown by S1 nuclease experiments these transcripts are alternatively spliced in a tissue-specific fashion generating mRNAs that encode tissue-specific protein isoforms. Antibodies were raised to synthetic peptides identical in sequence to the unique portion of each protein. Western blots of one-dimensional polyacrylamide gels using the type-specific antibodies confirmed and extended the results obtained from the S1 nuclease experiments. The indirect flight muscle is the only tissue in the adult that accumulates the alternatively spliced mRNA. The choice between splicing pathways involves the use of a nonconsensus 3' splice junction in larvae and in the tubular muscles of adults, whereas in the indirect flight muscle of the adult only consensus sequences are utilized. The involvement of a trans-acting factor to activate the nonconsensus splice site in the myotubes of larvae and the tubular myotubes of adults is proposed.

Animals↗
PubMed1986

Chromosome 8 breakpoint far 3' of the c-myc oncogene in a Burkitt's lymphoma 2;8 variant translocation is equivalent to the murine pvt-1 locus.

The 2;8 variant translocation of human Burkitt's lymphomas is closely related cytogenetically to the t(6;15) of murine plasmacytomas; both involve a reciprocal exchange between the Ig kappa locus and a band region indistinguishable from that bearing the c-myc oncogene. To define their molecular relationship, we have compared cloned chromosome 8 DNA from the t(2;8) breakpoint in the human Burkitt's lymphoma JBL2 with cloned DNA from the murine pvt-1 locus, the major chromosome 15 breakpoint region in murine t(6;15). DNA sequencing and Southern blot analysis shows that these two regions are homologous. Thus the t(2;8) in JBL2 is the molecular equivalent of many murine t(6;15). The murine pvt-1 locus lies an unknown distance 3' of c-myc; analysis of DNA from several tumours with c-myc amplification reveals that pvt-1 is co-amplified in at least one case, placing pvt-1 approximately 100-500 kb 3' of c-myc. The significance of these results with respect to the role of pvt-1 in tumorigenesis is discussed.

Animals↗
PubMed1986

An inexpensive microcomputer digital imaging system for densitometry: quantitative autoradiography of insulin receptors with 125I and LKB Ultrofilm.

This article describes a video digitizing system designed for measuring film optical density. The system, which is based on a 6-bit (64 gray level) digitizer, solid state video camera, and Apple II microcomputer, digitizes a rectangular area selected by the operator and converts the gray level values into preselected standard units. In order to develop autoradiographic standard curves for quantitative autoradiography with 125I-insulin, liver slices labeled with 125I-insulin and plastic sections containing known amounts of tritium were apposed to the same sheet of LKB Ultrofilm for exposures of 1-7 days. The results indicate that 3H plastic standards can be used to calibrate QAR of 125I-labeled ligands with LKB Ultrofilm. The Apple system was also used to measure binding of 125I-insulin to the external plexiform layer (EPL) in slices of the rat olfactory bulb. Results suggest that the EPL has two binding sites for insulin, a high affinity site with Kd = 1.0 X 10(-8) M and a low affinity site having a Kd = 1.4 X 10(-5) M.

Animals↗
PubMed1986

Proviral integration site Mis-1 in rat thymomas corresponds to the pvt-1 translocation breakpoint in murine plasmacytomas.

Two loci independently implicated in T-and B-lymphocyte neoplasia are shown to be equivalent. The Mis-1 locus is a common proviral integration site in retrovirally induced rat T lymphomas, while the pvt-1 locus on murine chromosome 15 frequently translocates to the kappa locus in plasmacytomas bearing 6;15 translocations. By comparing cloned sequences, we show that pvt-1 is the murine homolog of Mis-1.

Animals↗
PubMed1985

Variant (6;15) translocations in murine plasmacytomas involve a chromosome 15 locus at least 72 kb from the c-myc oncogene.

The variant (6;15) translocations in murine plasmacytomas join the myc oncogene-bearing band of chromosome 15 and the immunoglobulin kappa band of chromosome 6. We recently cloned a region from chromosome 15 linked to C kappa and have now used probes from that region to define the major locus of plasmacytoma variant translocations, which we denote pvt-1. In five of nine plasmacytomas we analysed, the 6;15 translocation resulted from reciprocal recombination between the C kappa locus and a 4.5-kb region of pvt-1. Moreover, nearby we located the region shown by others to have undergone a complex (15;12;6) translocation in plasmacytoma PC7183. All the chromosome 6 breakpoints fell between 1 and 3 kb 5' to C kappa but only two were near J kappa genes. Thus the J kappa -C kappa region appears to be a recombination 'hot spot' in lymphocytes, but the breaks are unlikely to be mediated via V/J recombination enzymes. Comparison of a cloned 108-kb region across pvt-1 and another of 52 kb across c-myc established that the pvt-1 breakpoints lie at least 72 kb from the c-myc promoters. Since c-myc is expressed at a substantial level, the 6;15 translocation apparently activates c-myc. Activation may occur directly, at a remarkable distance along the chromosome, or indirectly, via a putative pvt-1 gene product.

Animals↗
PubMed1985

Diamond-Blackfan syndrome in adult patients.

Two adults with pure red cell aplasia are described. No extrinsic etiologic mechanisms were identified. Evidence of anemia was long-standing and varied in severity. Musculoskeletal abnormalities (webbed neck, Sprengel's and Klippel-Feil deformities, and hand abnormalities) were similar to those seen in the congenital form of red cell aplasia (Diamond-Blackfan syndrome). As in the congenital variety, adrenal cortical steroids resulted in hematologic repair. These observations suggest that congenital (Diamond-Blackfan) pure red cell aplasia may be first recognized in adulthood and that steroids provide a potential therapeutic modality.

Adult↗
PubMed1985

An unsuspected arsenic poisoning murder disclosed by forensic autopsy.

An unsuspected case of homicidal arsenic poisoning, clinically thought to be a primary hematopoietic disorder, was uncovered by an expanded toxicologic screen which is performed in all medical examiner's cases in which the decedent displays gastrointestinal symptoms prior to death. Arsenic concentrations were: blood, 7.2 mg/liter; liver, 15 mg/kg; and kidney, 6 mg/kg.

Adult↗
PubMed1982

Similarities between motion parallax and stereopsis in human depth perception.

Random dot techniques were used to investigate the human visual system's sensitivity to sinusoidal depth modulations specified by motion parallax information. Thresholds for perceiving depth were found to be smallest when the spatial frequency of the depth corrugations was between 0.2 and 0.5 c/deg visual angle. These data were compared with the equivalent thresholds for perceiving depth corrugations specified by binocular disparity using similar apparatus and psychophysical procedures. The similarity between the sensitivity functions is suggestive of a closer relationship between the two systems than has previously been thought.

Depth Perception↗
PubMed1982

Simultaneous and successive contrast effects in the perception of depth from motion-parallax and stereoscopic information.

Prolonged inspection of a three-dimensional corrugated surface resulted in a successive contrast effect, or aftereffect, of depth, whereby a subsequently-viewed physically-flat test surface appeared to be corrugated in depth with the opposite phase to the adapting surface. The aftereffect occurred both when the depth was specified by motion parallax, in the absence of all other sources of depth information, and when it was specified solely by stereoscopic information. The depth aftereffect was measured by 'nulling' the apparent depth in the test surface with physical relative motion or binocular disparity until the test surface appeared flat. Up to 70% of the depth in the adapting surface was necessary to null the aftereffect. Simultaneous contrast effects in the perception of three-dimensional surfaces were used to investigate the spatial interactions that exist in the processing of motion-parallax and stereoscopic information. A physically vertical surface appeared to slope in depth in the opposite direction to the slope of a surrounding surface. In this case up to 50% of the slope of the inducing surface was necessary to null the contrast effect. Similar results were again obtained for motion-parallax and stereoscopic depth.

Adaptation, Ocular↗