Elevated Tissue Kallikrein Activity in Airway Secretions from Patients with Tracheobronchitis Associated with Prolonged Mechanical Ventilation

The clinical course of patients undergoing prolonged mechanical ventilation is often complicated by the development of purulent tracheobronchitis. The purpose of this study was to assess whether ventilator-associated hypersecretion is associated with elevated levels of tissue kallikrein (TK) activity. TK can induce marked bronchial inflammation in animal models and TK activity is increased in the airway secretions of symptomatic asthmatics. It has not been studied in conditions with predominantly neutrophilic bronchial secretions, although animal data indicate that neutrophil elastase may stimulate TK activity. We measured TK activity in airway secretions of patients undergoing mechanical ventilation for more than 4 weeks (PMV group) and in two comparator groups: patients with cystic fibrosis, who were colonized with Pseudomonas aeruginosa (CF group) and patients undergoing mechanical ventilation for less than one week who did not have clinical evidence of purulent airway secretions (acute mechanical ventilation, AMV group). We also compared the level of neutrophil elastase (NE) activity, an index of neutrophil activation, in the three patient groups. TK and NE activity in the sol phase were measured by the degradation of chromogenic substrates (DL Val-Leu-Arg pNA and N-Methoxy Succinyl Ala-Ala-Pro-Val pNA, respectively). Intergroup differences in cell counts were not significant. However, TK activity was significantly less in the AMV group than in the PMV and cystic fibrosis patients (Kruskal-Wallis ANOVA, p < 0.05). Elastase activity was significantly greater in the CF group (p < 0.05) than in the other two groups. Compared to patients undergoing short-term mechanical ventilation (AMV group), TK activity was elevated in patients with purulent tracheobronchitis associated with prolonged mechanical ventilation (PMV group). The elevation in TK activity in these patients is comparable to levels in sputum from patients with cystic fibrosis (CF group), although the latter had a significantly higher level of NE activity. The observation of increased TK activity in patients with neutrophilic airway inflammation suggests that TK may play a role in modulating inflammation in ventilator-associated tracheobronchitis and may be worthy of further study to determine its source and significance.

Bench testing of nebulizers: a comparison of three methods

Although nebulizers can vary widely in performance, there is no uniformly accepted method for bench testing these devices. In the present study, we compared three bench methods of measuring the performance of three commercial jet nebulizers (Whisper Jet [WJ; Marquest Medical, Englewood, CO], Sidestream [SS; Marquest Medical], and Vixone [VO; Westmed, Tucson, AZ] to assess the impact of the method of testing on reported nebulizer performance. Each nebulizer was charged with 3 mL of albuterol mixed with a radiotracer (technetium [99mTc]), and the radioactivity captured on a paper filter was expressed as a percentage of the nebulizer charge (% delivered). The nebulizers were tested with and without duplication of spontaneous respiration by a piston pump (spontaneous respiration and standing cloud methods, respectively). The nebulizers were also tested using a model of mechanical ventilation (mechanical ventilation method). For all three devices, the addition of the standardized breathing pattern significantly reduced the % delivered with all three nebulizers compared with the standing cloud method. For the standing cloud method, the presence of the T-piece/mouth-piece significantly reduced the % delivered with the WJ but not with the other two devices. The mechanical ventilation method had the lowest % delivered for all three devices. The magnitude of the differences between nebulizers varied with duration of treatment. The findings of this study emphasize the importance of bench testing that duplicates intended clinical usage, because significant differences in nebulizer performance may be manifested under certain clinical conditions but not under others.

Sarcoidosis in a patient with AIDS: a manifestation of immune restoration syndrome

Sarcoidosis has been rarely reported in the presence of HIV infection. Helper T-lymphocyte depletion may attenuate granuloma formation. We present a patient who developed active sarcoidosis after being started on highly active antiretroviral therapy (HAART), which increased his CD4 count and decreased his viral load. There have been reports of exaggerated responses to mycobacteria and viruses with the restoration of T-cell function after HAART in HIV-infected patients. We propose that active sarcoidosis seen in this patient is also a manifestation of this newly observed "immune restoration disease."

No evidence of human herpesvirus 8 infection in patients with paraneoplastic pemphigus, pemphigus vulgaris, or pemphigus foliaceus

Paraneoplastic pemphigus has been associated with both malignancies and multicentric Castleman's disease; the latter is a rare angiolymphoproliferative disorder that has also been linked with human herpesvirus 8 (HHV8) infection. Other diseases definitively associated with HHV8 include Kaposi's sarcoma and primary effusion lymphoma. In a search for additional HHV8-associated diseases, patients with paraneoplastic pemphigus, as well as patients with pemphigus vulgaris and pemphigus foliaceus, were studied. Using an immunofluorescence assay able to specifically detect antibodies directed against lytically induced HHV8 antigens, HHV8 antibodies were not detected in sera from 24 patients with paraneoplastic pemphigus (including 10 with concomitant Castleman's disease) nor from 19 patients with pemphigus vulgaris. Sera from patients with Kaposi's sarcoma and from healthy U.S. blood donors were positive (25 of 26) and negative (none of 20), respectively. In addition, HHV8 DNA was not found in frozen lesional skin of five patients with pemphigus vulgaris and five patients with pemphigus foliaceus by nested polymerase chain reaction (lower limit of detection = 10 copies viral DNA per microg total cellular DNA). Finally, tissue sections of lesional skin from 10 patients with pemphigus vulgaris were negative for HHV8 by in situ hybridization, using probes able to detect both latently and lytically expressed HHV8 genes in Kaposi's sarcoma tissue. In summary, no evidence of HHV8 infection was found in all types of pemphigus using a variety of methods. These findings do not support a general role for HHV8 in skin diseases associated with immunosuppression.

Visualization of human herpesvirus type 8 in Kaposi's sarcoma by light and transmission electron microscopy

BACKGROUND

Human herpesvirus type 8 (HHV-8) has been associated with Kaposi's sarcoma, body cavity-based lymphoma (BCBL), and multicentric Castleman's disease through DNA, in situ hybridization, and serologic studies. HHV-8 has been visualized only in HHV-8-positive/Epstein-Barr virus (EBV)-negative/ cytomegalovirus (CMV)-negative BCBL cell lines, but not in HHV-8-positive/EBV-negative/ CMV-negative Kaposi's sarcoma lesions.

DESIGN

Kaposi's sarcoma of the skin, lymph node, and spleen from three patients with AIDS were analysed for HHV-8, EBV and CMV DNA by polymerase chain reaction (PCR), for HHV-8 RNA (Tl.1 riboprobe) by in situ hybridization (ISH), for viral inclusions by light microscopy, and for herpesviruses by transmission electron microscopy (TEM). Sections were also labeled with Tl.1 counterstained with CD34, an endothelial cell marker.

RESULTS

The skin lesion was DNA PCR-positive for HHV-8 and CMV (nested, but not single PCR), the lymph node was positive for HHV-8 and EBV, and the spleen was positive for only HHV-8. TEM revealed infection by a virus displaying the typical morphology and cytopathicity of herpesviruses. Hexagonal nucleocapsids and mature enveloped virions were present in vasoformative spindle cells and mononuclear cells, often resembling lymphocytes. Extrapolating from TEM to standard light microscopy on hematoxylin and eosin-stained paraffin sections, eosinophilic, targetoid intranuclear inclusions were identified within spindle cells which often lined vascular lumina. The Tl.1-riboprobe labeled CD34+ spindle cells containing intranuclear inclusions, as well as mononuclear cells within Kaposi's sarcoma and residual lymphoid tissue.

CONCLUSION

The herpesvirus visualized in Kaposi's sarcoma lesions has morphologic and cytopathic features typical of human herpesviruses, productively infects vasoformative spindle cells and mononuclear cells, and is consistent with HHV-8. It can also form intranuclear inclusions that are identifiable by light microscopy in hematoxylin and eosin sections and by ISH.

Near-drowning: epidemiology, pathophysiology, and initial treatment

Drowning is a major cause of accidental deaths, especially in children. The most serious pathophysiologic consequence of near-drowning is hypoxemia, which usually is due to aspiration-induced noncardiogenic edema. Therefore, initial resuscitative efforts need to be directed at establishing adequate oxygenation and ventilation, followed by rewarming and fluid administration. Although completely asymptomatic patients with normal vital signs, oxygenation and chest radiographs require only 4 to 6 hours of observation, many near-drowning victims will require at least 24 hours of observation. Despite these measures, approximately 25% of victims presenting to the Emergency Department will die and another 6% will develop neurological sequelae. Therefore, it is vital that better efforts be made by the community in promoting and instituting water safety programs.

Vesical neck reconstruction in patients with epispadias-exstrophy complex

The achievement of satisfactory continence in the management of patients with the epispadias-exstrophy complex remains a challenge. Between 1971 and 1989, 22 children underwent vesical neck reconstruction at our hospital. Satisfactory continence was achieved in 17 of the 22 patients (77%), including 8 (36%) who are continent after a single vesical neck reconstruction and 9 of 13 who achieved continence after additional and/or adjunctive procedures. Additions and/or adjunctive procedures included revision of the vesical neck reconstruction, bladder augmentation and/or placement of an artificial urinary sphincter. We conclude that vesical neck reconstruction with or without additional and/or adjunctive procedures can result in an acceptable continence rate in patients with the epispadias-exstrophy complex.

Intraoral Masson's vegetant intravascular hemangioendothelioma

Two cases of Masson's vegetant intravascular hemangioendothelioma are described. The intraoral appearance of these reported lesions are rare. Due to histologic similarities to angiosarcoma and the benign progression of vegetant intravascular hemangioendothelioma, a thorough discussion of these diseases is presented.