Large-scale discovery of novel genetic causes of developmental disorders

Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.

Randomized, prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema

OBJECTIVE

To evaluate whether bilevel positive airway pressure, by actively assisting inhalation, more rapidly improves ventilation, acidemia, and dyspnea than continuous positive airway pressure (CPAP) in patients with acute pulmonary edema.

DESIGN

Randomized, controlled, double-blind trial.

SETTING

Emergency department in a university hospital.

PATIENTS

Twenty-seven patients, presenting with acute pulmonary edema, characterized by dyspnea, tachypnea, tachycardia, accessory muscle use, bilateral rales, and typical findings of congestion on a chest radiograph.

INTERVENTIONS

In addition to standard therapy, 13 patients were randomized to receive nasal CPAP (10 cm H2O), and 14 patients were randomized to receive nasal bilevel positive airway pressure (inspiratory and expiratory positive airway pressures of 15 and 5 cm H2O, respectively) in the spontaneous/timed mode that combines patient flow-triggering and backup time-triggering.

MEASUREMENTS AND MAIN RESULTS

After 30 mins, significant reductions in breathing frequency (32 +/- 4 to 26 +/- 5 breaths/min), heart rate (110 +/- 21 to 97 +/- 20 beats/min), blood pressure (mean 117 +/- 28 to 92 +/- 18 mm Hg), and Paco2 (56 +/- 15 to 43 +/- 9 torr [7.5 +/- 2 to 5.7 +/- 1.2 kPa]) were observed in the bilevel positive airway pressure group, as were significant improvements in arterial pH and dyspnea scores (p < .05 for all of these parameters). Only breathing frequency improved significantly in the CPAP group (32 +/- 4 to 28 +/- 5 breaths/min, p < .05). At 30 mins; the bilevel positive airway pressure group had greater reductions in Paco2 (p = .057), systolic blood pressure (p = .005), and mean arterial pressure (p = .03) than the CPAP group. The myocardial infarction rate was higher in the bilevel positive airway pressure group (71%) compared with both the CPAP group (31%) and historically matched controls (38%) (p = .05). Duration of ventilator use, intensive care unit and hospital stays, and intubation and mortality rates were similar between the two groups.

CONCLUSIONS

Bilevel positive airway pressure improves ventilation and vital signs more rapidly than CPAP in patients with acute pulmonary edema. The higher rate of myocardial infarctions associated with the use of bilevel positive airway pressure highlights the need for further studies to clarify its effects on hemodynamics and infarction rates, and to determine optimal pressure settings.

The role of fiberoptic endoscopy in the management of corrosive ingestion and modified endoscopic classification of burns

We prospectively evaluated the role of fiberoptic esophagogastroduodenoscopy in the management of 81 patients with corrosive ingestion. A total of 381 endoscopic examinations were performed: 88 within 96 hours following corrosive ingestion, 108 between the third and ninth week, and 185 during the period of follow-up after bougie dilation of esophageal strictures. The customary endoscopic classification of burns (grades 0 to 3) was modified by subdividing grade 2 burns into 2a and 2b, and grade 3 burns into 3a and 3b for prognostic and therapeutic implications. There was no significant correlation between oropharyngeal and upper gastrointestinal tract injury. Early major complications and deaths were confined to patients with grade 3 burns. All patients with grade 0, 1, and 2a burns recovered without sequelae. The majority of patients (71.4%) with grade 2b injury and all survivors with grade 3 injury developed esophageal or gastric cicatrization, or both, which needed endoscopic or surgical treatment. There were no complications related to endoscopy. We conclude that early endoscopy is not only a safe, reliable, and accurate diagnostic tool in such patients, but also is of crucial importance in management and prognosis.

An efficient method for qualitative screening of phosphate-solubilizing bacteria

An efficient protocol was developed for qualitative screening of phosphate-solubilizing bacteria, based upon visual observation. Our results indicate that, by using our formulation containing bromophenol blue, it is possible to quickly screen on a qualitative basis the phosphate-solubilizing bacteria. Qualitative analysis of the phosphate solubilized by various groups correlated well with grouping based upon quantitative analysis of bacteria isolated from soil, effect of carbon, nitrogen, salts, and phosphate solubilization-defective transposon mutants. However, unlike quantitative analysis methods that involve time-consuming biochemical procedures, the time for screening phosphate-solubilizing bacteria is significantly reduced by using our simple protocol. Therefore, it is envisaged that usage of this formulation based upon qualitative analysis will be salutary for the quick screening of phosphate-solubilizing bacteria. Our results indicate that the formulation can also be used as a quality control test for expeditiously screening the commercial bioinoculant preparations, based on phosphate solubilizers.

SAP90 binds and clusters kainate receptors causing incomplete desensitization

The mechanism of kainate receptor targeting and clustering is still unresolved. Here, we demonstrate that members of the SAP90/PSD-95 family colocalize and associate with kainate receptors. SAP90 and SAP102 coimmunoprecipitate with both KA2 and GluR6, but only SAP97 coimmunoprecipitates with GluR6. Similar to NMDA receptors, GluR6 clustering is mediated by the interaction of its C-terminal amino acid sequence, ETMA, with the PDZ1 domain of SAP90. In contrast, the KA2 C-terminal region binds to, and is clustered by, the SH3 and GK domains of SAP90. Finally, we show that SAP90 coexpressed with GluR6 or GluR6/KA2 receptors alters receptor function by reducing desensitization. These studies suggest that the organization and electrophysiological properties of synaptic kainate receptors are modified by association with members of the SAP90/PSD-95 family.

Assessment of the severity of primary depressive illness. Wakefield self-assessment depression inventory

A self-assessment inventory for measuring severity of depressive illness is described, Its chief merits are brevity and simplicity. The correlation with the Hamilton Rating Scale is +0·87. At a cut-off level of 14–15 points 3% of patients and 7·5% of ‘Normals’ are misclassified. The mean scores for male and female patients do not differ significantly and the small positive correlation of score with age is of little practical significance. The limitations in this inventory are discussed but, despite them, it has practical value and merits further development.

Infliximab is associated with attenuated immunogenicity to BNT162b2 and ChAdOx1 nCoV-19 SARS-CoV-2 vaccines in patients with IBD

OBJECTIVE

Delayed second dose SARS-CoV-2 vaccination trades maximal effectiveness for a lower level of immunity across more of the population. We investigated whether patients with inflammatory bowel disease treated with infliximab have attenuated serological responses to a single dose of a SARS-CoV-2 vaccine.

DESIGN

Antibody responses and seroconversion rates in infliximab-treated patients (n=865) were compared with a cohort treated with vedolizumab (n=428), a gut-selective anti-integrin α4β7 monoclonal antibody. Our primary outcome was anti-SARS-CoV-2 spike (S) antibody concentrations, measured using the Elecsys anti-SARS-CoV-2 spike (S) antibody assay 3-10 weeks after vaccination, in patients without evidence of prior infection. Secondary outcomes were seroconversion rates (defined by a cut-off of 15 U/mL), and antibody responses following past infection or a second dose of the BNT162b2 vaccine.

RESULTS

Geometric mean (SD) anti-SARS-CoV-2 antibody concentrations were lower in patients treated with infliximab than vedolizumab, following BNT162b2 (6.0 U/mL (5.9) vs 28.8 U/mL (5.4) p<0.0001) and ChAdOx1 nCoV-19 (4.7 U/mL (4.9)) vs 13.8 U/mL (5.9) p<0.0001) vaccines. In our multivariable models, antibody concentrations were lower in infliximab-treated compared with vedolizumab-treated patients who received the BNT162b2 (fold change (FC) 0.29 (95% CI 0.21 to 0.40), p<0.0001) and ChAdOx1 nCoV-19 (FC 0.39 (95% CI 0.30 to 0.51), p<0.0001) vaccines. In both models, age ≥60 years, immunomodulator use, Crohn's disease and smoking were associated with lower, while non-white ethnicity was associated with higher, anti-SARS-CoV-2 antibody concentrations. Seroconversion rates after a single dose of either vaccine were higher in patients with prior SARS-CoV-2 infection and after two doses of BNT162b2 vaccine.

CONCLUSION

Infliximab is associated with attenuated immunogenicity to a single dose of the BNT162b2 and ChAdOx1 nCoV-19 SARS-CoV-2 vaccines. Vaccination after SARS-CoV-2 infection, or a second dose of vaccine, led to seroconversion in most patients. Delayed second dosing should be avoided in patients treated with infliximab.

TRIAL REGISTRATION NUMBER

ISRCTN45176516.

Prospective trial of high-frequency oscillation in adults with acute respiratory distress syndrome

OBJECTIVE

To evaluate the safety and efficacy of high-frequency oscillatory ventilation (HFOV) in adult patients with the acute respiratory distress syndrome (ARDS) and oxygenation failure.

DESIGN

Prospective, clinical study.

SETTING

Intensive care and burn units of two university teaching hospitals.

PATIENTS

Twenty-four adults (10 females, 14 males, aged 48.5 +/- 15.2 yrs, Acute Physiology and Chronic Health Evaluation II score 21.5 +/- 6.9) with ARDS (lung injury score 3.4 +/- 0.6, Pao2/Fio2 98.8 +/- 39.0 mm Hg, and oxygenation index 32.5 +/- 19.6) who met one of the following criteria: Pao2 < or =65 mm Hg with Fio2 > or =0.6, or plateau pressure > or =35 cm H2O.

INTERVENTIONS

HFOV was initiated in patients with ARDS after varying periods of conventional ventilation (CV). Mean airway pressure (Paw) was initially set 5 cm H2O greater than Paw during CV, and was subsequently titrated to maintain oxygen saturation between 88% and 93% and Fio2 < or =0.60.

MEASUREMENTS AND MAIN RESULTS

Fio2, Paw, pressure amplitude of oscillation, frequency, blood pressure, heart rate, and arterial blood gases were monitored during the transition from CV to HFOV, and every 8 hrs thereafter for 72 hrs. In 16 patients who had pulmonary artery catheters in place, cardiac hemodynamics were recorded at the same time intervals. Throughout the HFOV trial, Paw was significantly higher than that applied during CV. Within 8 hrs of HFOV application, and for the duration of the trial, Fio2 and Paco2 were lower, and Pao2/Fio2 was higher than baseline values during CV. Significant changes in hemodynamic variables following HFOV initiation included an increase in pulmonary artery occlusion pressure (at 8 and 40 hrs) and central venous pressure (at 16 and 40 hrs), and a reduction in cardiac output throughout the course of the study. There were no significant changes in systemic or pulmonary pressure associated with initiation and maintenance of HFOV. Complications occurring during HFOV included pneumothorax in two patients and desiccation of secretions in one patient. Survival at 30 days was 33%, with survivors having been mechanically ventilated for fewer days before institution of HFOV compared with nonsurvivors (1.6 +/- 1.2 vs. 7.8 +/- 5.8 days; p =.001).

CONCLUSIONS

These findings suggest that HFOV has beneficial effects on oxygenation and ventilation, and may be a safe and effective rescue therapy for patients with severe oxygenation failure. In addition, early institution of HFOV may be advantageous.

Prospective randomized trial of laparoscopic gastrojejunostomy versus duodenal stenting for malignant gastric outflow obstruction

BACKGROUND

We prospectively compared laparoscopic gastrojejunostomy with duodenal stenting as a means of palliating malignant gastric outflow obstruction.

METHODS

A total of 27 patients with malignant gastric outflow obstruction were randomized to either laparoscopic gastrojejunostomy (LGJ) or duodenal stenting (DS) over a 3-year period.

RESULTS

Thirteen patients underwent successful LGJ and 10 had successful DS. Eight patients had complications after LGJ, but none had complications after DS. Patients who underwent LGJ had a significant increase in visual analog pain score at day 1 (p = 0.05), and also had a longer hospital stay compared to those who underwent DS (11.4 vs. 5.2 days, p = 0.02). After DS, patients experienced an improvement in physical health at 1 month as measured using the Short Form-36 (SF-36) questionnaire (p < 0.01). There was no change following LGJ.

CONCLUSION

Duodenal stenting is a safe means of palliating malignant gastric outflow obstruction. It offers significant advantages for patients compared with minimal-access surgery.

Contribution of nitric oxide synthases 1, 2, and 3 to airway hyperresponsiveness and inflammation in a murine model of asthma

Asthma is a chronic disease characterized by increased airway responsiveness and airway inflammation. The functional role of nitric oxide (NO) and the various nitric oxide synthase (NOS) isoforms in human asthma is controversial. To investigate the role of NO in an established model of allergic asthma, mice with targeted deletions of the three known isoforms of NOS (NOS1, 2, and 3) were studied. Although the inducible (NOS2) isoform was significantly upregulated in the lungs of ovalbumin (OVA)-sensitized and -challenged (OVA/OVA) wild-type (WT) mice and was undetectable in similarly treated NOS2-deficient mice, airway responsiveness was not significantly different between these groups. OVA/OVA endothelial (NOS3)-deficient mice were significantly more responsive to methacholine challenge compared with similarly treated NOS1 and NOS1&3-deficient mice. Airway responsiveness in OVA/OVA neuronal (NOS1)-deficient and neuronal/endothelial (NOS1&3) double-deficient mice was significantly less than that observed in similarly treated NOS2 and WT groups. These findings demonstrate an important function for the nNOS isoform in controlling the inducibility of airway hyperresponsiveness in this model of allergic asthma.

Engineering Chinese hamster ovary cells to maximize sialic acid content of recombinant glycoproteins

We have engineered two Chinese hamster ovary cell lines secreting different recombinant glycoproteins to express high levels of human beta1,4-galactosyltransferase (GT, E.C. 2.4.1.38) and/or alpha2, 3-sialyltransferase (ST, E.C. 2.4.99.6). N-linked oligosaccharide structures synthesized by cells overexpressing the glycosyltransferases showed greater homogeneity compared with control cell lines. When GT was overexpressed, oligosaccharides terminating with GlcNAc were significantly reduced compared with controls, whereas overexpression of ST resulted in sialylation of >/=90% of available branches. As expected, GT overexpression resulted in reduction of oligosaccharides terminating with GlcNAc, whereas overexpression of ST resulted in sialylation of >/=90% of available branches. The more highly sialylated glycoproteins had a significantly longer mean residence time in a rabbit model of pharmacokinetics. These experiments demonstrate the feasibility of genetically engineering cell lines to produce therapeutics with desired glycosylation patterns.

Safety and efficacy of a sustained inflation for alveolar recruitment in adults with respiratory failure

OBJECTIVE

To assess the safety and efficacy of a sustained inflation, used as a lung volume recruitment maneuver in ventilated patients with hypoxemic respiratory failure.

DESIGN

Prospective data collection as part of a quality assurance program following introduction of a lung volume recruitment guideline in the intensive care unit.

SETTING

Academic medical-surgical critical care unit.

PATIENTS

Hypoxemic patients with bilateral pulmonary infiltrates. Patients with chronic obstructive pulmonary disease, pulmonary barotrauma and hemodynamic instability were excluded.

INTERVENTIONS

A sustained inflation using a pressure of 30 to 45 cmH2O was applied for 20 s. The pressure was determined as the lesser of 45 cmH2O or the peak pressure while ventilated at a tidal volume of 12 ml/kg. Intra-arterial blood pressure and pulse oximetry were monitored continuously.

MEASUREMENTS AND RESULTS

Significant improvement in oxygenation occurred in the majority of patients within 10 min. The mean oxygen saturation improved from 86.9 +/- 5.5 to 94.3 +/- 2.3% (p < 0.01). No significant adverse effects were noted: hypotension and mild oxygen desaturation occurred in some patients during the 20-s inflation, reversing rapidly after inflation was terminated. No barotrauma occurred.

CONCLUSIONS

A sustained inflation is a safe, clinically applicable method of lung volume recruitment which improves oxygenation in selected patients and may have a role in ventilatory management.

Serum autoantibodies to brain in Landau-Kleffner variant, autism, and other neurologic disorders

OBJECTIVE

Etiologically unexplained disorders of language and social development have often been reported to improve in patients treated with immune-modulating regimens. Here we determined the frequency of autoantibodies to brain among such children.

DESIGN

We collected sera from a cohort of children with (1) pure Landau-Kleffner syndrome (n = 2), (2) Landau-Kleffner syndrome variant (LKSV, n = 11), and (3) autistic spectrum disorder (ASD, n = 11). None had received immune-modulating treatment before the serum sample was obtained. Control sera (n = 71) were from 29 healthy children, 22 with non-neurologic illnesses (NNIs), and 20 children with other neurologic disorders (ONDs). We identified brain autoantibodies by immunostaining of human temporal cortex and antinuclear autoantibodies using commercially available kits.

RESULTS

IgG anti-brain autoantibodies were present in 45% of sera from children with LKSV, 27% with ASD, and 10% with ONDs compared with 2% from healthy children and control children with NNIs. IgM autoantibodies were present in 36% of sera from children with ASD, 9% with LKSV, and 15% with ONDs compared with 0% of control sera. Labeling studies identified one antigenic target to be endothelial cells. Antinuclear antibodies with titers >/=1:80 were more common in children with ASD and control children with ONDs.

CONCLUSION

Children with LKSV and ASD have a greater frequency of serum antibodies to brain endothelial cells and to nuclei than children with NNIs or healthy children. The presence of these antibodies raises the possibility that autoimmunity plays a role in the pathogenesis of language and social developmental abnormalities in a subset of children with these disorders.

Exertional leg symptoms other than intermittent claudication are common in peripheral arterial disease

BACKGROUND

Epidemiological data show that most community-dwelling men and women with lower-extremity peripheral arterial disease (PAD) do not have typical symptoms of intermittent claudication. We compared the prevalence of intermittent claudication, leg symptoms other than intermittent claudication, and absence of exertional leg symptoms between patients with PAD identified from a blood flow laboratory (group 1), patients with PAD in a general medicine practice (group 2), and control patients without PAD (group 3).

METHODS

Numbers of participants in groups 1, 2, and 3 were 137, 26, and 105, respectively. Patients with previously diagnosed PAD were excluded from groups 2 and 3. All participants underwent ankle-brachial index measurement and were administered the San Diego claudication questionnaire to assess leg symptoms.

RESULTS

Within groups 1, 2, and 3, prevalences of intermittent claudication were 28.5% (n = 39), 3.8% (n = 1), and 3.8% (n= 4), respectively. Prevalences of exertional leg symptoms other than intermittent claudication were 56.2% (n= 77), 42.3% (n= 11), and 19.0% (n = 20), respectively. Absence of exertional leg symptoms was reported by 15.3% (n= 21), 53.8% (n= 14), and 77.1% (n=81), respectively. Among patients with PAD, older age, male sex, diabetes mellitus, and group 2 vs group 1 status were associated independently with absence of exertional leg symptoms in multivariable regression analysis. Lower ankle-brachial index levels and group 1 vs group 2 status were associated with intermittent claudication.

CONCLUSIONS

Clinical manifestations of PAD are diverse, particularly among patients identified by ankle-brachial index screening. Exertional leg symptoms other than intermittent claudication are common in PAD. Patients with PAD who are older, male, diabetic, or identified with ankle-brachial index screening in a primary care setting are more likely to have asymptomatic PAD.

Systolic function, readmission rates, and survival among consecutively hospitalized patients with congestive heart failure

We sought to describe the relation between left ventricular systolic function and rates of hospital readmission and survival among consecutively hospitalized patients with congestive heart failure. Medical records were reviewed for these patients at an academic medical center between Jan. 1, 1992, and Dec. 31, 1993. Left ventricular systolic function assessments performed within 6 months before discharge were used to classify left ventricular systolic function. Hospital readmission rates and survival through Dec. 31, 1994, were compared between patients with systolic dysfunction and those with preserved systolic function. Among 412 patients hospitalized with a primary diagnosis of congestive heart failure, 224 had undergone a left ventricular function assessment during the 6 months before hospital discharge. In-hospital mortality and readmission rates were higher among patients without a recent assessment of left ventricular systolic function. Of patients with systolic dysfunction, 55% versus 41% of patients with preserved systolic function were either readmitted or had an emergency room visit within 6 months after discharge (p = 0.06). At 27 months' follow-up, cumulative survival probabilities were 65% for patients with preserved systolic function, 65% for patients with systolic dysfunction, and 60% for patients without a left ventricular systolic function assessment (p = 0.24). Patients without a recent left ventricular systolic function assessment have significantly higher hospital readmission rates than patients with a recent systolic function assessment. Among hospitalized patients, mortality rates are comparable between patients with systolic dysfunction and those with preserved systolic function. However, patients with heart failure with systolic dysfunction may have higher readmission rates.

Short-term pulmonary vasodilation with L-arginine in pulmonary hypertension

BACKGROUND

Endothelial dysfunction may contribute to the pathogenesis of pulmonary hypertension through impaired production of the endothelium-derived vasodilator nitric oxide (NO). L-Arginine, the substrate for NO synthase (NOS), has a vasodilatory effect in systemic vascular beds and can correct abnormal endothelium-dependent vasodilation. It has been suggested that these two effects of L-arginine are mediated through NOS metabolism and enhanced NO production. Therefore, we assessed the short-term pulmonary hemodynamic effects of exogenous L-arginine in patients with pulmonary hypertension of various origins.

METHODS AND RESULTS

During continuous hemodynamic monitoring, 10 subjects with pulmonary hypertension (mean pulmonary artery pressure [PAP], 54 +/- 5 mm Hg [mean +/- SEM]) received a 30-minute control infusion of hypertonic saline followed by a 30-minute infusion of 500 mg/kg of L-arginine. The hemodynamic effects of L-arginine were compared with those of prostacyclin titrated to maximally tolerated doses. The hemodynamic response to L-arginine was also studied in 5 subjects with heart failure but without pulmonary hypertension (mean PAP, 20 +/- 2 mm Hg) and 5 healthy control subjects. In subjects with pulmonary hypertension, infusion of L-arginine reduced mean PAP by 15.8 +/- 3.6% (P < .005) and pulmonary vascular resistance (PVR) by 27.6 +/- 5.8% (P < .005) compared with decreases of 13.0 +/- 5.5% (P < .005) and 46.6 +/- 6.2% (P < .005), respectively, with prostacyclin. L-Arginine infusion also increased the mean plasma level of L-arginine from 59 +/- 6 mumol/L to 10,726 +/- 868 mumol/L (P < .005), which was associated with a significant increase in the plasma level of L-citrulline, the immediate product of NOS metabolism of L-arginine. Moreover, the peak plasma level of L-citrulline correlated significantly with the reductions in mean PAP (r = .71, P < .05) and PVR (r = .70, P < .05), consistent with vasodilation mediated by NOS metabolism of exogenous L-arginine and increased NO production. L-Arginine also had a modest hypotensive effect in healthy control subjects and reduced systemic vascular resistance in subjects with heart failure in the absence of pulmonary hypertension. However, only small reductions in absolute pulmonary vascular resistance were observed in this latter group in response to L-arginine that did not reach significance.

CONCLUSIONS

An exaggerated short-term pulmonary vasodilatory response to L-arginine in patients with pulmonary hypertension suggests a relative impairment in pulmonary vascular endothelial NO production that may contribute to increased pulmonary vascular tone and thus be important in the pathophysiology of pulmonary hypertension.

Differential requirement for classic and novel PKC isoforms in respiratory burst and phagocytosis in RAW 264.7 cells

The binding of Ab (IgG)-opsonized particles by FcgammaRs on macrophages results in phagocytosis of the particles and generation of a respiratory burst. Both IgG-stimulated phagocytosis and respiratory burst involve activation of protein kinase C (PKC). However, the specific PKC isoforms required for these responses have yet to be identified. We have studied the involvement of PKC isoforms in IgG-mediated phagocytosis and respiratory burst in the mouse macrophage-like cell line, RAW 264.7. Like primary monocyte/macrophages, their IgG-mediated phagocytosis was calcium independent and diacylglycerol sensitive, consistent with novel PKC activation. Respiratory burst in these cells was Ca2+ dependent and inhibited by staurosporine and calphostin C as well as by the classic PKC-selective inhibitors Gö 6976 and CGP 41251, suggesting that classic PKC is required. In contrast, phagocytosis was blocked by general PKC inhibitors but not by the classic PKC-specific drugs. RAW 264.7 cells expressed PKCs alpha, betaI, delta, epsilon, and zeta. Subcellular fractionation demonstrated that PKCs alpha, delta, and epsilon translocate to membranes during phagocytosis. In Ca2+-depleted cells, only novel PKCs delta and epsilon increased in membranes, and the time course of their translocation was consistent with phagosome formation. Confocal microscopy of cells transfected with green fluorescent protein-conjugated PKC alpha or epsilon confirmed that these isoforms translocated to the forming phagosome in Ca-replete cells, but only PKC epsilon colocalized with phagosomes in Ca2+-depleted cells. Taken together, these results suggest that the classic PKC alpha mediates IgG-stimulated respiratory burst in macrophages, whereas the novel PKCs delta and/or epsilon are necessary for phagocytosis.

Elevated nitric oxide concentrations in isolated lower airway gas of asthmatic subjects

Previous studies have raised the possibility that the measurement of nitric oxide (NO.) concentrations in expired air may represent a noninvasive measure of lower airway inflammation. To address the question of whether the elevated NO. recovered in mixed expired air from asthmatic subjects is a reflection of the pulmonary airway microenvironment or merely nasopharyngeal contamination, mixed expired NO. determinations were performed in five normal and five asthmatic subjects before and after orotracheal intubation (thereby isolating the lower airway gas from ambient air contamination or gas conditioned in the nasopharynx). The mixed expired NO. concentrations determined in patients with asthma were significantly elevated (p < 0.05 or less) above those of normal subjects in both the pre- and postintubation samples. After intubation, mixed expired NO. levels were 4.7 +/- 1.3 ppb and 13.2 +/- 2.0 ppb in normal and asthmatic individuals, respectively; the difference in these values was statistically significant (p < 0.01). Lower airway gas, sampled through the bronchoscope during a breathhold, was found to contain NO. concentrations of 7.0 +/- 1.2 ppb and 40.5 +/- 5.6 ppb at the tracheal carina of normal and asthmatic individuals, respectively. The asthmatic values were significantly (p < 0.01) elevated above those found in normal subjects. These findings indicate that the difference in mixed expired NO. of normal subjects and asthmatics reflects a difference in NO. concentration present in the lower airway.

Reciprocal regulation of anaerobic and aerobic cell wall mannoprotein gene expression in Saccharomyces cerevisiae

The DAN/TIR genes encode nine cell wall mannoproteins in Saccharomyces cerevisiae which are expressed during anaerobiosis (DAN1, DAN2, DAN3, DAN4, TIR1, TIR2, TIR3, TIR4, and TIP1). Most are expressed within an hour of an anaerobic shift, but DAN2 and DAN3 are expressed after about 3 h. At the same time, CWP1 and CWP2, the genes encoding the major mannoproteins, are down-regulated, suggesting that there is a programmed remodeling of the cell wall in which Cwp1 and Cwp2 are replaced by nine anaerobic counterparts. TIP1, TIR1, TIR2, and TIR4 are also induced during cold shock. Correspondingly, CWP1 is down-regulated during cold shock. As reported elsewhere, Mox4 is a heme-inhibited activator, and Mot3 is a heme-induced repressor of the DAN/TIR genes (but not of TIP1). We show that CWP2 (but not CWP1) is controlled by the same factors, but in reverse fashion-primarily by Mot3 (which can function as either an activator or repressor) but also by Mox4, accounting for the reciprocal regulation of the two groups of genes. Disruptions of TIR1, TIR3, or TIR4 prevent anaerobic growth, indicating that each protein is essential for anaerobic adaptation. The Dan/Tir and Cwp proteins are homologous, with the greatest similarities shown within three subgroups: the Dan proteins, the Tip and Tir proteins, and, more distantly, the Cwp proteins. The clustering of homology corresponds to differences in expression: the Tip and Tir proteins are expressed during hypoxia and cold shock, the Dan proteins are more stringently repressed by oxygen and insensitive to cold shock, and the Cwp proteins are oppositely regulated by oxygen and temperature.

Ingestion of corrosive acids. Spectrum of injury to upper gastrointestinal tract and natural history

We have prospectively evaluated 41 patients who ingested acid for location, extent, severity, and outcome of the injury to the upper gastrointestinal tract. The injury was assessed within 36 h of acid intake by endoscopy or surgery, or at autopsy. Symptoms and signs were unreliable in predicting the extent and severity of injury. The degree of burns was classified as follows: grade 0 in 2 patients, grade 1 in 3, grade 2 in 16, and grade 3 in 20. Esophageal injury was seen in 87.8% of the patients, gastric injury in 85.4%, and duodenal injury in 34.1%. All patients with grade 0, 1, and 2a injury recovered without sequelae. Acute complications occurred in 39.1% of the cases, and death in 12.2%. It is significant that all such patients had grade 3 burns. Five of the 8 patients with grade 2b injury and all survivors of grade 3 injury developed esophageal or gastric cicatrization, or both, which subsequently needed endoscopic or surgical treatment. We find that endoscopy is not only the tool of choice for diagnosis in such cases but also aids in deciding upon treatment and prognosis. We conclude that acid injury of the upper gastrointestinal tract is a very serious condition that affects the esophagus and stomach equally and results in high morbidity and mortality.

Heterotopic ossification after central nervous system trauma: A current review

Neurogenic heterotopic ossification (NHO) is a disorder of aberrant bone formation affecting one in five patients sustaining a spinal cord injury or traumatic brain injury. Ectopic bone forms around joints in characteristic patterns, causing pain and limiting movement especially around the hip and elbow. Clinical sequelae of neurogenic heterotopic ossification include urinary tract infection, pressure injuries, pneumonia and poor hygiene, making early diagnosis and treatment clinically compelling. However, diagnosis remains difficult with more investigation needed. Our pathophysiological understanding stems from mechanisms of basic bone formation enhanced by evidence of systemic influences from circulating humor factors and perhaps neurological ones. This increasing understanding guides our implementation of current prophylaxis and treatment including the use of non-steroidal anti-inflammatory drugs, bisphosphonates, radiation therapy and surgery and, importantly, should direct future, more effective ones.

Three mouse models of muscular dystrophy: the natural history of strength and fatigue in dystrophin-, dystrophin/utrophin-, and laminin alpha2-deficient mice

To optimize and evaluate treatments for muscular dystrophy, it is important to know the natural history of the disease in the absence of therapeutic intervention. Here we characterized disease progression of three mutant mouse strains of muscular dystrophy: mdx mice, which lack dystrophin; mdx:utrn-/- mice, which also lack utrophin; and dy/dy mice, which are deficient in laminin alpha2. Normal mice show a marked increase in forelimb strength over the first 10 weeks of life and little fatigue (<5%) over five consecutive strength trials. Mdx and mdx:utrn-/- mice demonstrate less strength then normal mice and approximately 40% fatigue at each age. Mdx mice become obese but mdx:utrn-/- mice do not. Dy/dy mice remain small and are much weaker than mdx and mdx:utrn-/- mice at all ages even when normalized to weight; however, they show only minimal fatigue (10%). This work demonstrates a distinct pattern of disease progression in each model and provides a foundation for assessing strategies for improving strength in each model.