Comparison of hepatitis C viral loads in patients with or without coinfection with different genotypes

Hepatitis C virus genotyping was assessed for 257 chronic hepatitis C patients with viral loads above 1,000 IU/ml. Twelve patients were coinfected with more than one genotype. Their median viral loads did not differ significantly from those observed for monoinfected patients, which in turn did not vary significantly among different genotypes.     

Effects of stimulant medications on the EEG of children with Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive type.

Stimulant medications are the most commonly-used treatments for Attention-Deficit/Hyperactivity Disorder (ADHD) in North America and Australia, although it is still not entirely known how these medications work. This study investigated the effects of stimulant medications on the EEG of children with the Inattentive type of ADHD. An initial EEG was recorded during an eyes-closed resting condition and Fourier transformed to provide absolute and relative power estimates for the delta, theta, alpha and beta bands. Theta/alpha and theta/beta ratios were also calculated. Subjects were placed on a 6-month trial of a stimulant and a second EEG was recorded at the end of the trial. Subjects were included in this study only if they showed a good clinical response during the trial. The unmedicated ADHD group had significantly greater absolute and relative theta, less relative alpha, and higher theta/alpha and theta/beta ratios than the control group. The stimulant medications resulted in a normalisation of the EEG, with changes in the theta, alpha and beta bands being most evident. These results suggest that stimulants act to increase cortical arousal in children with ADHD, normalising their EEG.     

Heterotrimeric G proteins and the platelet-derived growth factor receptor-beta contribute to hypoxic proliferation of smooth muscle cells

Hypoxic proliferation of pulmonary arterial smooth muscle cells (PASMC) is mitogen dependent, but the signaling pathways mediating hypoxia-induced cell growth are not well understood. We investigated hypoxic proliferation in primary cultures from porcine pulmonary artery smooth muscle. The cells were grown in medium with or without platelet-derived growth factor (PDGF)-B, a potent smooth muscle cell mitogen. Hypoxia induced upregulation of PDGF receptor-beta expression, the primary receptor for PDGF-B. However, PDGF-B-mediated hypoxic enhancement of proliferation was abolished by pertussis toxin, indicating (1) involvement of heterotrimeric Galpha i proteins and (2) minimal effect of increased PDGF receptor expression in hypoxic enhancement of proliferation. We treated PASMC with labeled, nonhydrolyzable analogs of GTP to determine directly if GTP binding proteins were activated by hypoxia in PASMC. We show that hypoxia stimulates GTP incorporation in PASMC both in the presence and absence of PDGF-B. Serum-starved PASMC are able to increase their incorporation of GTP after only 10 min of hypoxia, and this response is not pertussis toxin sensitive. In serum-starved PASMC, we show that hypoxia stimulates incorporation of GTP into a 44-kD protein. The results show that heterotrimeric G proteins are involved in hypoxia-induced signaling in pulmonary vascular smooth muscle cells.     

Inhibition of Escherichia coli Translocation from the Gastrointestinal Tract by Normal Cecal Flora in Gnotobiotic or Antibiotic-Decontaminated Mice

Escherichia coli C25 maintained population levels of 10(9) to 10(10) per g of cecum and translocated to 100% of the middle mesenteric lymph nodes in gnotobiotic mice monoassociated with E. coli C25. Intragastric inoculation of these mice with the cecal contents from specific-pathogen-free mice reduced the population levels of E. coli C25 to 10(6) per g of cecum and completely inhibited translocation to the mesenteric lymph nodes. Intragastric inoculation with heat-treated, Formalintreated, or filtered cecal contents did not reduce the population levels of E. coli C25 or reduce the incidence of translocation of E. coli C25 to the mesenteric lymph nodes. Thus, viable bacteria apparently are required in the cecal contents inocula to reduce the population levels and the incidence of translocation of E. coli C25. Treatment with streptomycin plus bacitracin decreased the anaerobic bacterial levels in these gnotobiotic mice, allowing increased population levels of E. coli C25 and increased translocation to the mesenteric lymph nodes. E. coli C25 also translocated to the mesenteric lymph nodes of specific-pathogen-free mice treated with streptomycin and bacitracin before colonization with E. coli C25. The high cecal population levels of E. coli C25 in these antibiotic-decontaminated specific-pathogen-free mice apparently overwhelm any barrier to translocation exerted by the immunologically developed lamina propria of the specific-pathogen-free mice. Inoculation of gnotobiotic mice with a cecal flora also reduced the population levels of an indigenous strain of E. coli with a concomitant inhibition of translocation of the indigenous E. coli to the mesenteric lymph nodes. Thus, bacterial antagonism of the gastrointestinal population levels of certain indigenous bacteria, such as E. coli, by other members of the normal bacterial flora appears to be an important defense mechanism confining bacteria to the gastrointestinal tract.     

Deletion of stem-loop 3 is compensated by second-site mutations within the Gag protein of human immunodeficiency virus type 1

Encapsidation of human immunodeficiency virus type 1 (HIV-1) RNA involves specific interactions between viral Gag proteins and viral RNA elements located at the 5' untranslated region (UTR). These RNA elements are termed packaging (psi) or encapsidation (E) signals and mainly comprise the stem-loop 1 (SL1) and SL3 RNA structures. We have previously shown that deletion of the SL1 sequences is compensated by second-site mutations within Gag. Similar studies are now extended to SL3 and the results demonstrate that deletion of this RNA structure is rescued by two point mutations, i.e., A11V in p2 and I12V in nucleocapsid (NC). These two compensatory mutations are different from those associated with the rescue of SL1 deletion, suggesting that SL1 and SL3 may bind to different residues of Gag during viral RNA packaging. Analysis of virion-derived RNA in native agarose gels shows that deletion of SL3 leads to decreases in both viral RNA packaging and dimerization. These defects are corrected by the compensatory mutations A11V and I12V. Yet, defects in viral RNA dimerization at an early stage that were caused by the SL3 deletion in the context of a viral protease-negative mutation cannot be overcome by these two suppressor mutations. Therefore, the positive effects of A11V and I12V on dimerization of the SL3-deleted RNA must have taken place at the maturation stage.     

The application of operative ultrasound immediately following carotid endarterectomy

One hundred and seventy-five carotid bifurcations have been scanned using intraoperative ultrasonic imaging. The technique is simple, reproducible, rapid, and reliable. Intimal flaps, clamp stenoses, residual plaques, and platelet accumulations were detected by this method. Most technical defects occurred in the external carotid artery (12%), and it is recommended that significant lesions remaining in this vessel should be removed. Defects in the internal carotid artery and common carotid artery were much less common (7%) and most of these were quite small, not requiring reopening. In fact, only 2% required reopening. In 1% of patients there were defects detected that led to stroke, which would have been removed on present criteria. Although there were other causes of stroke, technical error remains an immediately reversible source of postoperative stroke that can be avoided by the use of operative ultrasonic imaging. Long-term minor defects, as followed by noninvasive tests, rarely became significant and bore no relationship to the development of restenosis.

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Resumen Ciento setenta y cinco bifurcaciones carotídeas han sido estudiadas intraoperatoriamente al cierre de la arteriotomía para endarterectomía y una vez que los clamps y asas habían sido retirados y el flujo restaurado, mediante la imagenología de ultrasonido. La técnica es simple, reproducible, rápida, y confiable. Pliegues (flaps) de la íntima, estenosis por clamps, placas residuales, y acumulaciones plaquetarias fueron detectadas por este método. La mayoría de los defectos de técnica operatoria se presentaron en la carótida externa (12%) y por ello se recomienda que lesiones de significación que queden presentes en este vaso deben ser removidas. Los defectos en la arteria carótida interna y en la carótida primitiva fueron mucho menos frecuentes (7%) y su mayoría fueron mínimos y no requirieron reapertura del vaso. En 1% de los pacientes se presentaron defectos que dieron lugar a accidente cerebral los cuales, bajo criterios actuales, habrían sido removidos. Aunque hubo otras causas de accidente cerebral, los errores técnicos siguen siendo una fuente reversible inmediata de accidente cerebral postoperatorio que puede ser evitado con el uso de imagenología de ultrasonido intraoperatoria. Los defectos menores estudiados a largo plazo por medios no invasivos muy rara vez probaron ser de significación y no aparecieron relacionados con el desarrollo de reestenosis.

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Résumé Cent soixante-quinze fourches carotidiennes ont été soumises à une échographie per-opératoire. La méthode d'exploration est simple, aisée à répéter et fiable. Les lambeaux d'intima, les sténoses secondaires au clampage, les plaques laissées en place, les accumulations de plaquettes peuvent être détectées par cette exploration. La majorité des impairs opératoires s'observent au niveau de la carotide externe (12% des cas) et imposent la correction des lésions patentes. Les malfaçons au niveau de la carotide interne et de la carotide primitive sont moins fréquentes (7% des cas). Les lésions sont souvent peu importantes, leur correction ne s'imposant que dans 2% des cas. Dans 1% des cas, ces lésions artérielles opératoires aboutissent à une lésion cérébrale qui aurait pu être évitée. En effet, bien que d'autres causes de lésion cérébrale existent, les altérations imputables à l'acte chirurgical sont réversibles dès lors qu'elles sont mises en évidence par l'échographie opératoire. Les lésions mineures persistantes qui sont décelées par les tests non-invasifs ne sont que rarement à l'origine d'une sténose artérielle post-opératoire.

     

The Influence of Obesity on Hospital Admission After Outpatient Foot and Ankle Surgery

We examined the association of body mass index (BMI) with sociodemographic data, medical comorbidities and hospital admission following ambulatory foot and ankle surgery. We conducted an analysis utilizing data from the American College of Surgeons National Surgical Quality Improvement Program database from 2007 to 2016. Adult patients who underwent ankle surgery defined as ankle arthrodesis, ankle open reduction and internal fixation, and Achilles tendon repair in the outpatient setting. We examined 6 BMI ranges: <20 kg/m² underweight, ≥20 to <25 kg/m² normal weight, ≥25 to <30 kg/m² overweight, ≥30 to <40 kg/m² obese, ≥40 kg/m²to <50 kg/m² severely obese, and ≥50 kg/m² extremely obese. The primary outcome was hospital admission. We performed multivariable logistic regression and reported odds ratios (OR) and their associated 95% confidence interval (CI) and considered a p value of <.05 as statistically significant. Data extraction yielded 13,454 adult patients who underwent ambulatory ankle surgery. We then performed listwise deletion to exclude cases with missing observations. After excluding 5.4% of the data, the final study population included 12,729 patients. The overall rate of hospital admission was in the population was 18.6% (2,377/12,729). The overall rate of postoperative complications was 0.03% (4/12,729). We found no significant association of BMI with hospital admission following multivariable logistic regression. We recommend that BMI alone should not be solely used to exclude patients from having ankle surgery performed in an outpatient setting, especially since this patient group makes up a significant proportion of orthopedic surgery.     

A new species of Stephanostomum Looss, 1899 (Digenea, Acanthocolpidae) with a bizarre oral sucker: S. adlardi sp. nov. from the common coral trout Plectropomus leopardus (Lacepède, 1802) (Perciformes, Serranidae) from Lizard Island, Great Barrier Reef

A new species of Acanthocolpidae, Stephanostomum adlardi is described from the serranid Plectropomus leopardus from Lizard Island in the northern Great Barrier Reef. It differs from all previously described acanthocolpids in the structure of the oral sucker which is extended into dorsal and ventral lobes each bearing a row of spines. A phylogenetic tree estimated from combined nuclear small and partial large ribosomal RNA gene sequences shows that, despite the unusual oral sucker structure, the species is a true member of the genus Stephanostomum. The molecular results also suggest that Monostephanostomum nolani is derived from within Stephanostomum.     

The effect of lung inflation on the control of respiratory frequency in the neonate

1. We have measured the relationship between tidal volume (V_T) and the duration of inspiration (T_i) and expiration (T_e) for individual breaths (30 in each steady state).

2. Ten pre-term and ten term infants were studied during steady state while breathing 21% O₂, then 21% O₂ plus 2 and 4% CO₂.

3. In all infants, the average T_i at the various chemical drives was remarkably constant, and did not decrease as the tidal volume increased. However, at any given level of respiratory drive, there was a slightly positive correlation of V_T with T_i and T_e in 95% of the cases.

4. In four pre-term and two term infants, T_e increased with increasing respiratory drive. In these infants, therefore, instantaneous respiratory frequency (1/(T_i + T_e)) actually decreased as lung volume increased.

5. We suggest that T_i is independent of V_T within the range of volumes studied (up to 2 times the resting V_T) and that changes in instantaneous respiratory frequency (1/(T_i + T_e)) result from changes in T_e.