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Genomic gigantism: DNA loss is slow in mountain grasshoppers.

Several studies have shown DNA loss to be inversely correlated with genome size in animals. These studies include a comparison between Drosophila and the cricket, Laupala, but there has been no assessment of DNA loss in insects with very large genomes. Podisma pedestris, the brown mountain grasshopper, has a genome over 100 times as large as that of Drosophila and 10 times as large as that of Laupala. We used 58 paralogous nuclear pseudogenes of mitochondrial origin to study the characteristics of insertion, deletion, and point substitution in P. pedestris and Italopodisma. In animals, these pseudogenes are "dead on arrival"; they are abundant in many different eukaryotes, and their mitochondrial origin simplifies the identification of point substitutions accumulated in nuclear pseudogene lineages. There appears to be a mononucleotide repeat within the 643-bp pseudogene sequence studied that acts as a strong hot spot for insertions or deletions (indels). Because the data for other insect species did not contain such an unusual region, hot spots were excluded from species comparisons. The rate of DNA loss relative to point substitution appears to be considerably and significantly lower in the grasshoppers studied than in Drosophila or Laupala. This suggests that the inverse correlation between genome size and the rate of DNA loss can be extended to comparisons between insects with large or gigantic genomes (i.e., Laupala and Podisma). The low rate of DNA loss implies that in grasshoppers, the accumulation of point mutations is a more potent force for obscuring ancient pseudogenes than their loss through indel accumulation, whereas the reverse is true for Drosophila. The main factor contributing to the difference in the rates of DNA loss estimated for grasshoppers, crickets, and Drosophila appears to be deletion size. Large deletions are relatively rare in Podisma and Italopodisma.

Animals↗

Novel mutation in desmoplakin causes arrhythmogenic left ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a familial heart muscle disease characterized by structural, electrical, and pathological abnormalities of the right ventricle (RV). Several disease loci have been identified. Mutations in desmoplakin have recently been isolated in both autosomal-dominant and autosomal-recessive forms of ARVC. Primary left ventricular (LV) variants of the disease are increasingly recognized. We report on a large family with autosomal-dominant left-sided ARVC. METHODS AND RESULTS: The proband presented with sudden cardiac death and fibrofatty replacement of the LV myocardium. The family was evaluated. Diagnosis was based on modified diagnostic criteria for ARVC. Seven had inferior and/or lateral T-wave inversion on ECG, LV dilatation, and ventricular arrhythmia, predominantly extrasystoles of LV origin. Three had sustained ventricular tachycardia; 7 had late potentials on signal-averaged ECG. Cardiovascular magnetic resonance imaging in 4 patients revealed wall-motion abnormalities of the RV and patchy, late gadolinium enhancement in the LV, suggestive of fibrosis. Linkage confirmed cosegregation to the desmoplakin intragenic marker D6S2975. A heterozygous, single adenine insertion (2034insA) in the desmoplakin gene was identified in affected individuals only. A frameshift introducing a premature stop codon with truncation of the rod and carboxy terminus of desmoplakin was confirmed by Western blot analysis. CONCLUSIONS: We have described a new dominant mutation in desmoplakin that causes left-sided ARVC, with arrhythmias of LV origin, lateral T-wave inversion, and late gadolinium enhancement in the LV on magnetic resonance images. Truncation of the carboxy terminus of desmoplakin and consequent disruption of intermediate filament binding may account for the predominant LV phenotype.

Adult↗

Homologous recombination among three intragene Alu sequences causes an inversion-deletion resulting in the hereditary bleeding disorder Glanzmann thrombasthenia.

The crucial role of the human platelet fibrinogen receptor in maintaining normal hemostasis is best exemplified by the autosomal recessive bleeding disorder Glanzmann thrombasthenia (GT). The platelet fibrinogen receptor is a heterodimer composed of glycoproteins IIb (GPIIb) and IIIa (GPIIIa). Platelets from patients with GT have a quantitative or qualitative abnormality in GPIIb and GPIIIa and can neither bind fibrinogen nor aggregate. Very few genetic defects have been identified that cause this disorder. We describe a kindred with GT in which the affected individuals have a unique inversion-deletion mutation in the gene for GPIIIa. Patient platelets lacked both GPIIIa protein and mRNA. Southern blots of patient genomic DNA probed with an internal 1.0-kb GPIIIa cDNA suggested a large rearrangement of this gene but were normal when probed with small GPIIIa cDNA fragments that were outside the mutation. Cytogenetics and pulsed-field gel analysis of the GPIIIa gene were normal, making a translocation or a very large rearrangement unlikely. Additional Southern analyses suggested that the abnormality was not a small insertion. We constructed a patient genomic DNA library and isolated fragments containing the 5' and 3' breakpoints of the mutation. The nucleotide sequence from these genomic clones was determined and revealed that, relative to the normal gene, the mutant allele contained a 1-kb deletion immediately preceding a 15-kb inversion. The DNA breaks occurred in two inverted and one forward Alu sequence within the gene for GPIIIa and in the left, right, and left arms, respectively, of these sequences. There was a 5-bp repeat at the 3' terminus of the inversion.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

A case of acute myelogenous leukemia with MLL-AF10 fusion caused by insertion of 5' MLL into 10p12, with concurrent 3' MLL deletion.

Structural abnormalities involving the mixed-lineage leukemia (MLL) gene on 11q23 have been associated with hematological malignancies. The rearrangement of MLL occurs during translocations and insertions involving a variety of genes on the partner chromosome. We report a rare case of acute myelogenous leukemia (AML-M2) with 11q23 abnormalities. Fluorescence in situ hybridization (FISH) using a commercial dual-color MLL probe detected an atypical signal pattern: one fusion signal, two green signals smaller than those usually detected, and no orange signals. Spectral karyotyping (SKY) analysis indicated that one green signal was detected on the short arm of derivative chromosome 10, and the other green signal on the long arm of a derivative chromosome 11, on which no orange signal was detected. A long-distance inverse polymerase chain reaction (LDI-PCR) identified the fusion partner gene, in which intron 6 of MLL was fused with intron 8 of AF10 on 10p12 in the 5' to 3' direction. Our observations indicated that the MLL-AF10 fusion gene resulted from the insertion of part of the region that included the 5' MLL insertion into 10p12; this was concurrent with the deletion of 3' MLL.

Acute Disease↗

The effect of perfusion on T1 after slice-selective spin inversion in the isolated cardioplegic rat heart: measurement of a lower bound of intracapillary-extravascular water proton exchange rate.

Many NMR measurements of cardiac microcirculation (perfusion, intramyocardial blood volume) depend on some kind of assumption of intracapillary-extravascular water exchange rate, e.g., fast exchange. The magnitude of this water exchange rate, however, is still unknown. The intention of this study was to determine a lower limit for this exchange rate by investigating the effect of perfusion on relaxation time. Studies were performed in the isolated perfused cardioplegic rat heart. After slice-selective inversion, the spin lattice relaxation rate of myocardium within the slice was studied as a function of perfusion and compared with a mathematical model which predicts relaxation rate as a function of perfusion and intracapillary-extravascular exchange rate. A linear relationship was found between relaxation rate T(-1) and perfusion P normalized by perfusate/tissue partition coefficient of water, lambda: deltaT(-1) = m x deltaP/lambda with 0.82 < or = m < or = 1.06. Insertion of experimental data in the model revealed that a lower bound of the exchange rate from intra- to extravascular space is 6.6 s(-1) (4.5 s(-1), P < 0.05), i.e., the intracapillary lifetime of a water molecule is less than 150 ms (222 ms, P < 0.05). Based on this finding, the T1 mapping after slice-selective inversion could become a valuable noncontrast NMR method to measure variations of perfusion.

Animals↗

Mitochondrial DNA rearrangements: intracellular information system.

The extent of mtDNA rearrangements has been analyzed in nDNA preparations of rat and human with a statistically representative group of oligonucleotides directed to two regions of mtDNA: genes for cytochrome oxidase subunits I and III. Human PCR preparations generated with oligonucleotides directed 'normally' showed the expected fragment for mtDNA and the presence of a plethora of fragments with rearrangements (deletions and insertions), in contrast to rat PCR preparations under the same reaction conditions in which these kinds of rearranged fragments were rarely observed. Both human and rat PCR preparations generated with oligonucleotides directed 'inversely' showed numerous fragments, some of which showed differences in copy number correlating with distinct phases during development/aging. Sequence analysis of some normal and rearranged fragments demonstrated in all cases DNA sequences 99% homologous with other mtDNA sequences at rearranged fragments. No evidence of nuclear DNA sequences was found. The following scheme is proposed for mtDNA rearrangements during the lifetime of an organism: variation in copy number of some fragments with inversions of mtDNA depends on the specific developmental/aging period; in old cells there is an increase in higher molecular weight mtDNA deletions. These findings strongly suggest that the mtDNA rearrangements play a role as an intracellular 'information system'.

Adult↗

Systemic anticoagulation and prevention of hemodialysis catheter malfunction.

Although chronic anticoagulation is commonly prescribed to prevent thrombosis and malfunction of hemodialysis tunneled cuffed catheters (TCC), there are only limited data regarding its efficacy. The aim of this prospective study was to evaluate whether anticoagulation with adjusted-dose warfarin targeting an international normalized ratio (INR) of 1.5-2.0 is associated with improved catheter outcome in long-term patients at high risk of TCC malfunction. Among the 65 patients included in the study, 35 were considered at high risk (i.e., patients with a history of previous TCC thrombosis requiring catheter replacement and/or with TCC malfunction occurring within 2 weeks after catheter insertion in the absence of mechanical problems) and were prescribed warfarin, whereas 30 low-risk patients did not receive anticoagulation. During follow-up, TCC malfunction, defined as the need for inversion of catheter lines and/or recombinant tissue-type plasminogen activator infusion, was observed in 61.5% of patients. Among patients receiving warfarin, 19 (54.3%) achieved adequate anticoagulation (i.e., > 80% of follow-up INR values and INR value at the time of malfunction within target range). Anticoagulation was considered inadequate in 16 patients (45.7%). Malfunction-free catheter survival at 9 months was 47.1% in patients with adequate anticoagulation compared with 8.1% in patients with inadequate anticoagulation (p = 0.01). This difference remained statistically significant after adjustment for aspirin intake. These results suggest that achieving adequate anticoagulation with target INR 1.5-2.0 may prevent TCC malfunction and improve catheter outcome.

Aged↗

Sequence and uptake specificity of cloned sonicated fragments of Haemophilus influenzae DNA.

Our data support the conclusion that all tight binding of DNA by competent cells of Haemophilus influenzae is due to 9 base pairs (bp) of the 11-bp motif 5'-AAGTGCGGTCA or its inverse complement, TGACCGCACTT. Sonicated chromosomal DNA of H. influenzae was absorbed and extracted from competent cells to prepare a subpopulation of uptake fragments enriched for single uptake (binding) sequences. This DNA was inserted into the plasmid pUC18 and cloned into Escherichia coli. Whole sonicated chromosomal DNA was also cloned in pUC18 as a population of control fragments. Seventy-one plasmids were labeled with 3H and tested for DNA binding, and the inserts of 28 of them were sequenced. The control plasmid pUC18 was absorbed to competent H. influenzae cells at low levels of 5 to 10% of DNA added. The plasmids containing uptake inserts were mostly absorbed at levels of 70 to 80%, but a significant number contained inserts with an intermediate level of binding, 20 to 30%. The inserts of 15 plasmids were excised and tested for DNA uptake to demonstrate good agreement between uptake of these plasmids and their insert fragments. Sequencing of inserts revealed that the presence of 9 bp of the 11-bp motif was associated with tight binding. Some inserts with intermediate levels of binding had no significant similarities to the 9-bp sequence. The 9-bp sequence appeared to account for most of the binding to competent cells, but appreciable binding occurred with fragments without 9-bp homology. About one-third of the 9-bp uptake sequences were found as inverted repeats that could form strong stem-loop structures. It has been suggested by Goodman and Scocca (Proc. Nal. Acad. Sci. USA 85:6982-6986, 1988) that in Neisseria gonorrhoeae, uptake sequences occur as palindromes and act as transcription terminators. Although consistent, the data are insufficient to make this conclusion for uptake sequence palindromes in H. influenzae.

Base Sequence↗

Identification of genes negatively regulated by Fis: Fis and RpoS comodulate growth-phase-dependent gene expression in Escherichia coli.

Fis is a nucleoid-associated protein in Escherichia coli that has been shown to regulate recombination, replication, and transcription reactions. It is expressed in a transient manner under batch culturing conditions such that high levels are present during early exponential phase and low levels are present during late exponential phase and stationary phase. We have screened a random collection of transposon-induced lac fusions for those which give decreased expression in the presence of Fis. Thirteen different Fis-repressed genes were identified, including glnQ (glutamine high-affinity transport), mglA (methyl-galactoside transport), xylF (D-xylose-binding protein), sdhA (succinate dehydrogenase flavoprotein subunit), and a newly identified aldehyde dehydrogenase, aldB. The LacZ expression patterns revealed that many of the fusions were maximally expressed at different stages of growth, including early log phase, mid- to late log phase, and stationary phase. The expression of some of the late-exponential- and stationary-phase genes was dependent on the RpoS sigma factor, whereas that of others was affected negatively by RpoS. We conclude that Fis negatively regulates a diverse set of genes and that RpoS can function to both activate and inhibit the expression of specific genes.

Amino Acid Sequence↗

Alteration of the rugose phenotype in waaG and ddhC mutants of Salmonella enterica serovar Typhimurium DT104 is associated with inverse production of curli and cellulose.

The rugose (also known as wrinkled or rdar) phenotype in Salmonella enterica serovar Typhimurium DT104 Rv has been associated with cell aggregation and the ability, at low temperature under low-osmolarity conditions, to form pellicles and biofilms. Two Tn5 insertion mutations in genes that are involved in lipopolysaccharide (LPS) synthesis, ddhC (A1-8) and waaG (A1-9), of Rv resulted in diminished expression of colony rugosity. Scanning electron micrographs revealed that the ddhC mutant showed reduced amounts of extracellular matrix, while there was relatively more, profuse matrix production in the waaG mutant, compared to Rv. Both mutants appeared to produce decreased levels of curli, as judged by Western blot assays probed with anti-AgfA (curli) antibodies but, surprisingly, were observed to have increased amounts of cellulose relative to Rv. Comparison with a non-curli-producing mutant suggested that the alteration in curli production may have engendered the increased presence of cellulose. While both mutants had impaired biofilm formation when grown in rich medium with low osmolarity, they constitutively formed larger amounts of biofilms when the growth medium was supplemented with either glucose or a combination of glucose and NaCl. These observations indicated that LPS alterations may have opposing effects on biofilm formation in these mutants, depending upon either the presence or the absence of these osmolytes. The phenotypes of the waaG mutant were further confirmed in a constructed, nonpolar deletion mutant of S. enterica serovar Typhimurium LT2, where restoration to the wild-type phenotypes was accomplished by complementation. These results highlight the importance of an integral LPS, at both the O-antigen and core polysaccharide levels, in the modulation of curli protein and cellulose production, as well as in biofilm formation, thereby adding another potential component to the complex regulatory system which governs multicellular behaviors in S. enterica serovar Typhimurium.

Bacterial Proteins↗

Plasma cortisol and aggression in boys with ADHD.

OBJECTIVE: The results of several studies suggest an inverse relationship between cortisol secretion and aggressive behavior. This study examined basal plasma cortisol levels in aggressive and nonaggressive boys with attention-deficit hyperactivity disorder (ADHD). METHOD: The subjects were 23 aggressive and 27 nonaggressive boys with ADHD, aged 7 to 11 years. After 3 days of a low monoamine diet and an overnight fast, an indwelling catheter was inserted into a forearm vein. Samples for plasma cortisol levels were obtained 105 and 115 minutes after insertion of the catheter. RESULTS: A one-way analysis of covariance (ANCOVA) controlling for body mass revealed no significant difference in plasma cortisol between the aggressive and nonaggressive boys. Furthermore, when the children were alternatively divided on the basis of the presence or absence of a DSM-III-R diagnosis of conduct disorder, a one-way ANCOVA again revealed no significant difference in cortisol levels. CONCLUSIONS: The hypothesized inverse relationship between cortisol secretion and aggressive behavior in boys with ADHD was not found. These findings are consistent with a large body of literature indicating that the biological substrate of aggression is complex and that the identification of biological laboratory markers of aggressive behavior is not a clinically useful strategy at this time.

Aggression↗

Evaluation of techniques for measuring negative intramuscular pressures in humans.

Negative external pressure has been used previously in experiments on the blood circulation in humans and is currently being considered as a counter-measure to the musculoskeletal deconditioning which occurs during the exposure to microgravity. Intramuscular pressure (IMP) measurement is an important tool for determining the effectiveness of the transmission of negative pressure. Therefore two IMP techniques, a fibre optic transducer-tipped catheter and a fluid-filled teflon catheter with side holes, were evaluated using laboratory and human tests for measuring negative pressures. For the laboratory tests, both catheters were placed inside a lower leg negative pressure (LLNP) chamber and pressures of 0, -20, -50, -80, -100 and back to 0 mmHg were applied. Both catheters measured pressures equally and remained stable over 1 min at all pressure levels. When the teflon catheter was infused at rates commonly used for IMP recordings at normal atmospheric pressures, the drip rate at the catheter tip increased inversely with the magnitude of negative pressure. The cables and pressure tubings of the catheters within the LLNP chamber were not affected by the negative pressures. For tests in humans, the catheters were inserted side by side in the tibialis anterior muscle in eight legs of four human volunteers. The leg was placed in the LLNP chamber and pressures of 0, -20, -50, -80 and back to 0 mmHg were applied. The teflon catheter was used without infusion. Both catheters measured IMP similarly at rest and both remained stable over 1 min at all pressure levels; also the IMP during muscle contractions and immediately following contractions was similarly recorded by both catheters. We concluded that both catheter systems are suitable for recording negative pressures over a wide range. As is the case with recordings at normal atmospheric pressures, the fibre optic transducer-tipped catheter system may be preferred when recording IMP in a negative pressure environment when complex limb movements are involved.

Adult↗

A new complex variant Philadelphia chromosome, t(1;9;22)ins(17;22), characterized by fluorescence in situ hybridization in an adult ALL.

A new complex variant Philadelphia chromosome was detected in a 65-year-old man with acute, pre-B, lymphoblastic leukemia (ALL). The classic cytogenetic analysis identified an apparently balanced three-way translocation t(1;9;22)(q25;q34;q11.2). Fluorescence in situ hybridization (FISH) studies confirmed the translocation and showed bcr/abl fusion on the der(22). However, these studies revealed that the distal part of the bcr gene was not translocated onto chromosome 1 at 1q25, but inserted into chromosome 17 at 17p12-13. This complex variant translocation was described as a t(1;9;22)(q25;q34;q11.2)ins(17;22)(p12-13;q11.2q11.2). Secondary changes including +8, an inversion of the derivative chromosome 9, a translocation t(14;20)(q11;q13), and an additional derivative 22 were also identified in most of the abnormal cells. The patient died from systemic fungemia and multiorgan failure 9 months after the diagnosis of ALL. The clinical significance of complex variant Philadelphia chromosomes in ALL is reviewed and discussed.

Adult↗

Operative treatment of the difficult stage 2 adult acquired flatfoot deformity.

In the flexible pes planovalgus deformity of stage 2 posterior tibial tendon dysfunction, osteotomies appear to have a significant role in operative management by restoring more normal biomechanics, allowing tendon transfers to function successfully. The options when considering osteotomies for stage 2 disease include lateral column lengthening, medial displacement calcaneal osteotomy, and combined double osteotomy technique. The tight Achilles tendon should be lengthened as well. Lateral column lengthening has been used extensively for treatment of flexible flatfeet. It has been shown clinically and radiographically to address all 3 components of the pes planovalgus deformity present in stage 2 posterior tibial tendon dysfunction. Lateral column lengthening is used in combination with a medial soft tissue rebalancing procedure. The mechanism of action is still speculative but clearly is not owing to tensioning of the plantar fascia as previously thought. Despite the excellent correction of foot posture obtained by use of lateral column lengthening for adult acquired flatfoot, many clinicians have reservations about its use because of reported secondary increases in the calcaneocuboid joint pressures. This increase in pressure has been shown to occur experimentally, increasing the potential risk of calcaneocuboid joint arthrosis. This experimental evidence is supported by Phillips' study of the original Evans procedure, which resulted in a 65% incidence of calcaneocuboid joint arthrosis at 13-year follow-up. Mosier-LaClair et al reported a 14% incidence of calcaneocuboid joint arthritis at 5-year follow-up after double osteotomy for stage 2 posterior tibial tendon dysfunction. This incidence has not been proved true in the remainder of the literature surrounding this procedure and its use for flexible flatfoot. To address the concern regarding potential calcaneocuboid arthrosis secondary to lateral column lengthening, calcaneocuboid joint distraction arthrodesis has been explored as an alternative technique. The results show good initial correction, but the follow-up is extremely limited, and one study reported loss of correction over time. Longer follow-up is needed to determine whether or not this technique would provide the lasting correction seen with the Evans procedure. Calcaneocuboid joint lengthening arthrodesis does result in some limitation of adjacent hindfoot motion. Although this limitation is significantly less compared with talonavicular and subtalar joint fusion, this procedure may result in increased local pressures and arthrosis of the midfoot or hindfoot. For the above-mentioned reasons, longer follow-up studies are needed to determine whether calcaneocuboid joint distraction arthrodesis would prove to be a reliable and safe alternative for lateral column lengthening in the treatment of adult acquired flatfoot. Medial displacement calcaneal osteotomy has been used for correction of the pes planovalgus foot in posterior tibial tendon dysfunction. It has been used extensively for the surgical treatment of flexible flatfoot throughout the literature. Medial displacement osteotomy, in combination with flexor digitorum longus tendon transfer, can address all 3 components of adult acquired flatfoot. It does not recreate the medial longitudinal arch in all patients, however. Although the mechanism of action of medial displacement calcaneal osteotomy is unknown, it has been proved that it is not through the tightening of the plantar fascia in a windlass effect as previously thought. In contrast to lateral column lengthening, however, medial displacement calcaneal osteotomy does address the deforming valgus force of the Achilles tendon. Functionally transferring the insertion of the Achilles tendon medially removes a constant valgus-deforming force. The osteotomy can then act as a double tendon transfer with the flexor digitorum longus tendon to aid in foot inversion. For stage 2 posterior tibial tendon insufficiency, the authors favor the combination double osteotomy technique with a flexor digitorum longus tendon-to-medial cuneiform tendon transfer, débridement or removal of the posterior tibial tendon, and percutaneous heel cord lengthening. Early results were positive at 1.5 years after surgery with respect to maintenance of correction and functional improvement with no evidence of calcaneocuboid arthrosis. More recently, the intermediate 5-year follow-up has been assessed for this combination of procedures, and similar results were found. There was a high rate of patient satisfaction and functional improvement, and surgical correction of the flatfoot deformity was maintained and compared favorably with the contralateral normal foot. Although the intermediate follow-up found a 14% incidence of calcaneocuboid arthrosis, 50% of these patients had preoperative evidence of calcaneocuboid joint arthritis. (ABSTRACT TRUNCATED)

Adult↗

Effect of breathing circuit resistance on the measurement of ventilatory function.

BACKGROUND: The American Thoracic Society (ATS) has set the acceptable resistance for spirometers at less than 1.5 cm H2O/l/s over the flow range 0-14 l/s and for monitoring devices at less than 2.5 cm H2O/l/s (0-14 l/s). The aims of this study were to determine the resistance characteristics of commonly used spirometers and monitoring devices and the effect of resistance on ventilatory function. METHODS: The resistance of five spirometers (Vitalograph wedge bellows, Morgan rolling seal, Stead Wells water sealed, Fleisch pneumotachograph, Lilly pneumotachograph) and three monitoring devices (Spiro 1, Ferraris, mini-Wright) was measured from the back pressure developed over a range of known flows (1.6-13.1 l/s). Peak expiratory flow (PEF), forced expiratory flow in one second (FEV1), forced vital capacity (FVC), and mid forced expiratory flow (FEF25-75%) were measured on six subjects with normal lung function and 13 subjects with respiratory disorders using a pneumotachograph. Ventilatory function was then repeated with four different sized resistors (approximately 1-11 cmH2O/l/s) inserted between the mouthpiece and pneumotachograph. RESULTS: All five diagnostic spirometers and two of the three monitoring devices passed the ATS upper limit for resistance. PEF, FEV1 and FVC showed significant (p < 0.05) inverse correlations with added resistance with no significant difference between the normal and patient groups. At a resistance of 1.5 cm H2O/l/s the mean percentage falls (95% confidence interval) were: PEF 6.9% (5.4 to 8.3); FEV1 1.9% (1.0 to 2.8), and FVC 1.5% (0.8 to 2.3). CONCLUSIONS: The ATS resistance specification for diagnostic spirometers appears to be appropriate. However, the specification for monitoring devices may be too conservative. PEF was found to be the most sensitive index to added resistance.

Adult↗

Two sibs with partial trisomy 2q.

We report on two sibs with facial anomalies and developmental delay. Partial trisomy 2q was detected only after parental chromosome studies showed the father to carry a balanced interchromosomal insertion of 2 (q24.3-q32.1) into 5q.

Abnormalities, Multiple↗

Genetic analysis of regions of the Lactococcus lactis subsp. lactis plasmid pRS01 involved in conjugative transfer.

The genes responsible for conjugative transfer of the 48.4-kb Lactococcus lactis subsp. lactis ML3 plasmid pRS01 were localized by insertional mutagenesis. Integration of the IS946-containing plasmid pTRK28 into pRS01 generated a pool of stable cointegrates, including a number of plasmids altered in conjugative proficiency. Mapping of pTRK28 insertions and phenotypic analysis of cointegrate plasmids identified four distinct regions (Tra1, Tra2, Tra3, and Tra4) involved in pRS01 conjugative transfer. Tra3 corresponds closely to a region previously identified (D. G. Anderson and L. L. McKay, J. Bacteriol. 158:954-962, 1984). Another region (Tra4) was localized within an inversion sequence shown to correlate with a cell aggregation phenotype. Tra1 and Tra2, two previously unidentified regions, were located at a distance of 9 kb from Tra3. When provided in trans, a cloned portion of the Tra3 region complemented Tra3 mutants.

Chromosome Mapping↗

Isolation and field-inversion gel electrophoresis analysis of DNA markers located close to the Huntington disease gene.

A radiation-induced hybrid cell line containing 10-20 million base pairs of DNA derived from the terminal part of human 4p16 in a background of hamster chromosomes has been used to construct a genomic library highly enriched for human sequences located close to the Huntington disease (HD) gene. Recombinant phage containing human inserts were isolated from this library and used as hybridization probes against two other radiation hybrids containing human fragments with chromosomal breaks in 4p16 and against a human-hamster somatic cell hybrid that retains only the 4p15-4pter part of chromosome 4. Of 121 human phage tested, 6 were mapped distal to the HD-linked D4S10 locus. Since the HD gene is located between D4S10 and the 4p telomere, all of these sequences are likely to be closer to HD than D4S10, and any one of them may be a distal flanking marker for the disease locus. Long-range restriction map analysis performed with a field-inversion gel system shows that the six new loci are distributed in different places within 4p16. Although it is not possible to establish an order for the six sequences with the FIGE data, the results demonstrate that the region detected by these probes must span at least 2000 kb of DNA.

Animals↗