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Biomedical subjects

C A Moore

Publications and source records attributed to C A Moore.

At least 19 recordsLinked to original sources
PubMed1992

Familial occurrence of renal and Müllerian duct hypoplasia, craniofacial anomalies, severe growth and developmental delay.

Absence of the kidneys and of the Müllerian structures has been reported in many patients. We report on a brother and sister, born to nonconsanguineous parents, with renal hypoplasia, Müllerian duct hypoplasia, and strikingly similar facial abnormalities. Both sibs have severe growth and developmental retardation. We think that the unique clinical findings in these sibs represent a new syndrome. The embryological and genetic implications of this condition are discussed.

Abnormalities, Multiple↗
PubMed1992

Emergent applications of cardiopulmonary support: a multiinstitutional experience.

The use of emergent portable bypass systems is increasing. Because of limited patient use in any one institution, a combined experience can better determine the applicability of these systems. A total of 187 patients from 17 centers were analyzed. Causes leading to bypass initiation were cardiac arrest (125 patients), cardiogenic shock (44), profound hypothermia (7), pulmonary insufficiency (9), and miscellaneous (2). Weaning from bypass was successful in 30.5% (57 patients). Sixty-four patients (34.2%) were transferred to standard bypass or other modes of circulatory assist. Of the total population, 40 patients (21.4%) were alive greater than 30 days. There were no survivors of unwitnessed arrests. Major diagnostic or therapeutic interventions were carried out on bypass in 74.9% of all patients. In survivors, 77.1% (37/48) had major therapeutic interventions as compared with 50.0% (67/135) of nonsurvivors. Emergency portable bypass systems can successfully resuscitate and support cardiac hemodynamics, although the underlying causes necessitating bypass remain difficult to correct. When corrective intervention can be performed, there is an increased chance of survival. Unwitnessed arrest, prolonged cardiopulmonary resuscitation, and lack of treatment options are relative contraindications. Appropriate patient selection and early application of these systems should lead to improved survival.

Adolescent↗
PubMed1992

The correspondence of vocal tract resonance with volumes obtained from magnetic resonance images.

The increasing availability of magnetic resonance imaging (MRI) as a research, and even clinical, tool in speech production makes possible a wide range of quantitative methods in vocal tract measurement. In these initial stages of application, it is essential that the limits of the method be identified. The present investigation was designed to apply the techniques of digital image analysis and volumetric measurement to MRIs obtained for the vocal tract during production of continuant speech sounds, and to apply these measures to a well-established and thoroughly tested model of acoustic transmission (Stevens & House, 1955). The results demonstrated that, although there were several sources of relatively large error and measurement bias, the vocal tract volumes obtained from MRIs were significantly predictive of vocal tract resonance frequencies. These results are discussed with respect to limits and potential for future application of MRI to speech production research.

Adult↗
PubMed1992

Polysomnography of adults and elderly: sleep architecture, respiration, and leg movement.

Polysomnographic data recorded from a large sample of normal, healthy, adult volunteer subjects are reported. First and second night summary values are included. Results agree remarkably well with previously published findings and the age-related differences in sleep architecture that we found are described in detail. We also discuss some of the unique methodological problems associated with developing normative sleep values.

Adult↗
PubMed1991

Two nonallelic insulin genes in Xenopus laevis are expressed differentially during neurulation in prepancreatic embryos.

Insulin, traditionally regarded as a metabolic hormone, also can potently stimulate growth and differentiation in many cell types. To study further the potential role of insulin during early embryogenesis, we have used the amphibian Xenopus laevis, a versatile model of vertebrate development. Using (i) nucleotide sequences of two previously cloned cDNAs that correspond to two different nonallelic Xenopus insulin genes (both of which are expressed in the adult pancreas) and (ii) a modification of the highly sensitive reverse transcription-polymerase chain reaction (RT-PCR) method developed in our laboratory, designated RNA template-specific PCR (RS-PCR), we now find that mRNAs for both Xenopus insulins I and II are present in mature (stage VI) oocytes but not in less-mature oocytes (stages I and IV) or in unfertilized eggs. The Xenopus insulin II gene is differentially expressed during early neurulation (stage 13), while only the insulin I gene is expressed at stage 21, when the neural tube is closing and cephalization is beginning. During later stages (i.e., stage 26) there is a region in the head that appears to be transcribing only the insulin I gene, while mRNAs for both insulins I and II are present in the body region. These findings show that the two nonallelic insulin genes are expressed differentially in Xenopus embryos in a stage- and region-specific manner; because appropriate receptors are also present, we suggest a role for insulin during early nervous system development well before the emergence of pancreatic beta cells.

Alleles↗
PubMed1991

Ligase-free subcloning: a versatile method to subclone polymerase chain reaction (PCR) products in a single day.

Often, it is convenient to subclone polymerase chain reaction (PCR) products into a plasmid vector for subsequent replication in bacteria, but conventional subcloning methods often fail. We report a rapid and versatile method to subclone PCR products directionally into a specific site of virtually any plasmid vector. The procedure requires only four primers, does not require DNA ligase, and may be accomplished in a single day. Ligase-free subcloning is performed by incorporating into the PCR primers sequences at the 5' ends that result in PCR products whose 3' ends are complementary to the 3' ends of the recipient linearized plasmid. The PCR product and the linearized plasmid are spliced together in a second PCR reaction in which Taq polymerase extends the complementary overlapping 3' ends (ligation by overlap extension). Denaturation followed by heterologous reannealing and cyclization results in a cyclic recombinant plasmid with two nicks that may be used directly to transform competent Escherichia coli. In our hands, ligase-free subcloning is rapid, and offers many advantages over existing strategies.

Bacteriophage lambda↗
PubMed1991

RNA template-specific PCR: an improved method that dramatically reduces false positives in RT-PCR.

We report a novel modification of the reverse transcription PCR method, designated RNA template-specific PCR. With this approach, the 5' end of the first strand is tagged with a unique nucleotide sequence during reverse transcription that may then be exploited to amplify preferentially RNA-derived sequences. In our hands, RNA template-specific PCR retains the sensitivity of the traditional method, but greatly reduces the frequency of false positives, and virtually eliminates carryover contamination from PCR products amplified in previous experiments.

Animals↗
PubMed1990

Anterior ethmoid anatomy facilitates dacryocystorhinostomy.

The ethmoid air cell labyrinth lies adjacent to the medial orbital wall, extending even beyond the sutures of the ethmoid bone. Its anatomic relationship to the lacrimal sac fossa is important in lacrimal surgery. We evaluated computed tomographic scans of 190 orbits with normal ethmoid anatomy to define the anatomic relationship of anterior ethmoid air cells to the lacrimal sac fossa. In 93% of the orbits, the cells extended anterior to the posterior lacrimal crest, with 40% entering the frontal process of the maxilla. This anatomic relationship may be used to facilitate the osteotomy during dacryocystorhinostomy. During a 10-year period (310 cases), one of us routinely entered the anterior ethmoid air cells to initiate the osteotomy during dacryocystorhinostomy. This technique has helped to avoid lacerations of the nasal mucosa.

Adolescent↗
PubMed1990

Infantile hypophosphatasia: autosomal recessive transmission to two related sibships.

Hypophosphatasia, a rare heritable form of rickets/osteomalacia, is characterized by deficient activity of the tissue nonspecific (liver/bone/kidney) isoenzyme of alkaline phosphatase (ALP). Signs may be present prenatally or not until late adult life. Although the infantile form of hypophosphatasia has usually been categorized as an autosomal recessive (AR) disorder, several studies suggest that childhood cases are the consequence of either AR or autosomal dominant (AD) inheritance and adult cases are primarily AD. Eastman and Bixler (J Craniofac Genet Dev Biol 3:213-234, 1983) propose that all cases of hypophosphatasia may reflect AD inheritance with 85% penetrance and homozygous lethality. We report on 3 patients with hypophosphatasia in a black family, first manifested clinically during infancy, where the pattern of inheritance for each is consistent with AR transmission. Two were brothers who died from the disorder. The other patient, a cousin, presented with classic stigmata of hypophosphatasia during infancy, but is now age 5 1/2 years and has had a much milder clinical course. Although consanguinity is absent, the maternal grandmothers are sibs as are the maternal grandfathers and the paternal grandmothers. The family history is otherwise negative for skeletal or dental disease. Laboratory and radiographic results are consistent with heterozygosity in each parent. Fibroblast ALP activity is less than 1% normal in all 3 patients with no complementation observed in heterokaryon analysis. Accordingly, the genetic defects appear to be identical in all 3 patients. Our findings show that infantile hypophosphatasia may be inherited as an AR condition where there is variable expressivity and that homozygosity or compound heterozygosity, as may be the case in this family, is not necessarily lethal.

Black People↗
PubMed1990

Fetal brain disruption sequence.

The fetal brain disruption sequence is a recognizable pattern of defects that includes moderate to profound microcephaly, overlapping sutures, occipital bone prominence, and scalp rugae. The condition is postulated to arise from partial brain disruption during the second or third trimester with subsequent fetal skull collapse resulting from decreased intracranial hydrostatic pressure. Proposed causes include prenatal viral or parasitic infections and vascular disruptions. We report seven infants with the fetal brain disruption sequence. Two of these patients died. A changing phenotype with time was seen in three. Recognition of this phenotype is critical because the condition has a uniformly poor prognosis for infants but the recurrence risk in future pregnancies is low.

Abnormalities, Multiple↗
PubMed1990

Tracking of a "moving" fused auditory image under conditions that elicit the precedence effect.

Pursuit auditory tracking of a fused auditory image (FAI), based on stimulus conditions known to elicit the precedence effect phenomenon in sound localization, was investigated in 36 normal subjects and in a small group of subjects with known neuropathology. Movement of the FAI was simulated by incrementally varying the delay between two clicks presented, one each, from two loudspeakers placed on opposite sides of the listener. The group of normal listeners tracked the movement of the FAI without difficulty and with great accuracy; the perceived location of the FAI varied linearly with the interspeaker delay. The sensitivity of the task in detecting neural timing or integration deficits was investigated in 5 subjects with neuropathology, including subjects with unilateral temporal lobe lesions, multiple sclerosis, or dyslexia. These disorders, previously shown to disrupt neural timing, yielded characteristic patterns of tracking inaccuracy for this task. These subjects had no difficulty localizing either a moving unitary click source or sounds in daily life. These data support the suggestion that sound localization using stimulus conditions known to elicit the precedence effect places greater demands on neural timing and integration than conventional tests of localization, and may provide a more sensitive index of neural function.

Acoustics↗
PubMed1990

Effects of aging on the precedence effect in sound localization.

The precedence effect in sound localization can be evoked by presenting identical sounds (e.g., clicks) from pairs of loudspeakers placed on opposite sides of a subject's head. With appropriate inter-loudspeaker delays, normal subjects perceive a fused image originating from the side of the leading loudspeaker. Separate tests at loudspeaker delays ranging from 0 to 8 ms were presented to groups of young and elderly subjects. At 0 ms delay, young subjects perceived the fused image to be located halfway between the loudspeakers; at progressively longer delays, the image was perceived closer to the leading loudspeaker. Significant numbers of elderly subjects exhibited discrimination difficulties with delays below 0.7 ms.

Adult↗
PubMed1990

Tests of the precedence effect in sound localization reveal abnormalities in multiple sclerosis.

The precedence effect in sound localization involves presenting identical sounds (e.g., clicks) from pairs of matched speakers situated on opposite sides of a subject's head, with the clicks from one speaker preceding those from the other by a short interval. With appropriate delays, normal subjects perceive a fused image which originates from the side of the leading speaker. This test was administered to 24 patients with multiple sclerosis (MS). Separate tests involving speaker delays ranging from 0 msec (simultaneous presentation) to 8 msec were presented. At 0 msec delay, normal subjects perceived the fused image to be located halfway between the two speakers; at progressively longer delays, the image was perceived closer to the leading speaker. In contrast to normal subjects, a large proportion of the MS subjects exhibited difficulties with the task. The discrimination deficit was limited to delays below 1 msec, suggesting a problem involving an increased threshold for lateralizing the fused image away from midline toward the side of the leading speaker. The neural instability produced by demyelination in MS patients might account for this pattern of results.

Adult↗
PubMed1990

Thallium 201 kinetics in stunned myocardium characterized by severe postischemic systolic dysfunction.

The hypothesis tested in this study was that despite the presence of severe postischemic myocardial dysfunction ("stunning"), the extraction and subsequent intracellular washout of thallium 201 should be preserved as long as irreversible sarcolemmal membrane injury was avoided. To produce myocardial stunning, 19 open-chested dogs with a critical left anterior descending coronary artery (LAD) stenosis underwent 10 5-minute periods of total LAD occlusion, each interspersed by 10 minutes of reperfusion by reflow through the critical stenosis. In another 12 control dogs observed for the same time period, no LAD occlusions were performed after placement of the critical stenosis. Hemodynamics, regional myocardial thickening by quantitative two-dimensional echocardiography, and microsphere-determined regional blood flows were serially measured. In 18 stunned dogs, systolic thickening in the LAD zone was markedly reduced to 0.4 +/- 2.4% at 40 minutes after the 10th reperfusion period compared with 32.5 +/- 2.2% thickening (p less than 0.001) in 12 control dogs at a matched time. The 201Tl first-pass extraction fraction determined by a double-isotope method using intracoronary 201Tl administration was comparable after the 10th reflow in a subgroup of 13 stunned (0.78) and six control (0.79) dogs. The T1/2 for the intracellular washout rate was also not significantly different in another group of six stunned (60 +/- 13 minutes) and six control (53 +/- 14 minutes) dogs, nor was the percentage of the 201Tl dose initially distributed in the interstitial compartment (11 +/- 3% vs. 7 +/- 2%). Systemic hemodynamics and regional flows were comparable in the two groups at 40 minutes after the 10th reflow. No dog had evidence of myocardial necrosis by triphenyl tetrazolium chloride staining. Thus, normal myocardial 201Tl extraction and washout kinetics are observed in a canine model of severe postischemic dysfunction (stunning) produced by repetitive brief LAD occlusions. These findings might have important clinical implications concerning the application of rest 201Tl scintigraphy for evaluation of perfusion and viability in patients with coronary artery disease and regional myocardial asynergy that is ultimately reversible.

Animals↗
PubMed1989

A monoclonal antibody against the rod outer segment guanyl nucleotide-binding protein, transducin, blocks the stimulatory and inhibitory G proteins of adenylate cyclase.

GTP-binding proteins have been implicated as transducers of a variety of biological signaling processes. These proteins share considerable structural as well as functional homology. Due to these similarities, it was thought that a monoclonal antibody that inhibits the light activation of the rod outer segment GTP-binding protein, tranducin (Gt), might exert some functional effect upon the G proteins that regulate the adenylate cyclase system. Antibody 4A, raised against the alpha subunit of Gt, cross-reacted (by hybridization on nitrocellulose) with purified alpha subunits of other G proteins (Gi and Gs, regulatory guanyl nucleotide-binding proteins that mediate inhibition and stimulation of adenylate cyclase, respectively) as long as they were not denatured. This antibody, which interferes with rod outer segment cGMP phosphodiesterase activation by blocking interaction between rhodopsin and Gt, also interfered with actions of both the stimulatory and inhibitory G proteins of adenylate cyclase from rat cerebral cortex membranes. Effects of monoclonal antibody (mAb) 4A were dose-dependent and not reversed by washing. mAb 4A also blocked the Gi-mediated inhibition of adenylate cyclase in the cyc- variant of S49 lymphoma and in doing so raised the level of adenylate cyclase activity in both the cyc- variant and the S49 wild type. There was no effect of mAb 4A on adenylate cyclase activity of the resolved catalytic subunit. These results suggest that the well known sequence homologies among the G proteins involved in cellular signal transduction may extend to the sites that interact with other members of signal-transducing cascades (receptors and effector molecules). Therefore, antibody 4A may serve as a useful tool to probe the similarities and differences among the various systems.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1989

Familial distal arthrogryposis with craniofacial abnormalities: a new subtype of type II?

We report on 5 relatives in 3 generations with an apparent new type of distal arthrogryposis. These individuals have manifestations of type I distal arthrogryposis, but in addition, have craniofacial anomalies that include facial asymmetry, hypertelorism, downslanting palpebral fissures, high nasal bridge, malar hypoplasia, micrognathia, highly arched palate, notched chin, and posteriorly angulated ears. Their intelligence is normal. Although these manifestations preclude us from placing this family in the type I (isolated) distal arthrogryposis category, we also are unable to place them in any of the recognized subtypes of type II distal arthrogryposis. Thus, we think this family may have a previously undescribed form of autosomal dominant type II distal arthrogryposis.

Abnormalities, Multiple↗