Electron microscopic analysis of the normal and the activated pleural macrophage

Despite an apparent role in pleural pathophysiology, little information is known about pleural macrophage morphology. Intrapleural tetracycline (TCN) results in pleural macrophage influx and pleural fibrosis; intrapleural carrageenan (CAR) induces macrophage influx without ensuing fibrosis. Pleural macrophages collected from normal (NL) and TCN- or CAR-exposed rabbit pleural spaces were examined with electron microscopy. Cellular size; number of microvilli; pseudopods; coated pits (CP) and coated vesicles (CV); and prevalence of golgi, rough endoplasmic reticulum (RER), and intermediate filaments (IF) were determined. The means of each variable in each group were assessed by one-way analysis of variance, with post hoc testing performed by Scheffe F test; p < or = .05 was considered significant. TCN-stimulated pleural macrophages were characterized by their small perimeters. CAR-induced pleural macrophages were marked by their large size and abundant intracellular amorphous material. They had larger perimeters, areas, and diameters than the TCN-induced or normal macrophages and thus smaller numbers of CV + CP per area. The normal pleural macrophages were characterized by more IF, microvilli, and microvilli per perimeter than either the CAR- or TCN-induced pleural macrophages. No differences between groups were found in nuclear cytoplasmic ratios, number of pseudopods, and content of golgi or of RER. The results suggest that normal pleural macrophages and TCN- and CAR-induced pleural macrophages differ morphologically and that these morphologic differences reflect functional differences.

Early inflammatory response of minocycline and tetracycline on the rabbit pleura

The histopathologic findings were compared from 20 mg/kg intrapleural tetracycline hydrochloride (TCN) and three doses of intrapleural minocycline hydrochloride (5, 10, and 20 mg/kg) (MCN) in New Zealand white rabbits. Both TCN and MCN produced an early neutrophilic predominant pleural effusion that became mononuclear over 48 h. There was no difference in pleural fluid accumulation, number of adhesions, or histologically measured visceral and parietal pleural thickness between TCN and MCN (all p = ns). The TCN, 20 mg/kg, produced more visceral pleural plaque than MCN, 5 mg/kg (p < 0.05). Increasing MCN doses resulted in greater pleural fluid neutrophil accumulation. With higher dose MCN, greater mesothelial cell desquamation and fibroblast proliferation was evident compared to the 5 mg/kg dose. The MCN and TCN produce similar histopathologic condition in the rabbit pleura which suggests that MCN should cause a similar clinical response in humans.

Pleural effusions in hospitalized patients with AIDS

OBJECTIVE

To determine the incidence, cause, and characteristics of pleural effusions in hospitalized patients with the acquired immunodeficiency syndrome (AIDS).

DESIGN

Retrospective.

PARTICIPANTS

A total of 222 patients with AIDS hospitalized between January 1986 and January 1992 at the Medical University of South Carolina hospitals.

RESULTS

Pleural effusions occurred in 59 patients for an overall incidence of 27%. The mean age of the patients was 35 +/- 2 years (SE) and the male to female ratio was 5:1. The cause was infectious in 39 (66%) patients, noninfectious in 18 (31%), and unknown in 2 (3%). Pleural effusions were caused by bacterial pneumonia in 18 (31%) patients, Pneumocystis carinii pneumonia in 9 (15%), Mycobacterium tuberculosis in 5 (8%), septic embolism in 2 (3%), Nocardia asteroides in 2 (3%), cryptococcus neoformans in 2 (3%), and Mycobacterium arium intracellulare in 1 (2%). Among noninfectious causes (n = 18), hypoalbuminemia was the cause in 11 patients (19%), cardiac failure in 3 (5%), and atelectasis, Kaposi sarcoma, uremic pleurisy, and adult respiratory distress syndrome in 1 (2%) each. Patients with AIDS who had pleural effusions had significantly lower serum albumin levels and had lower CD4 counts than did those without pleural effusions (P < 0.001).

CONCLUSIONS

Pleural effusions are common in hospitalized patients with AIDS. Bacterial pneumonia is the most common cause for pleural effusion in AIDS. Large effusions are associated with Kaposi sarcoma and tuberculosis. Hypoalbuminemia is a common cause of noninfectious pleural effusions.

Tips for monitoring the position of a central venous catheter. How placement can go awry--even when the anatomy is normal

Malpositioning of a central venous catheter can cause potentially life-threatening complications. Knowledge of thoracic anatomy and close attention to proper insertion technique increase the likelihood of, but do not ensure, proper placement. Selection of a right-sided venous entry site reduces the risk of malpositioning. The return of nonpulsatile, dark-colored blood is a strong, but not infallible, indication of venous placement. Do not assume that venous system valves preclude malpositioning. Use chest films to confirm accurate insertion. When these are equivocal, take simultaneous blood samples from a peripheral artery and the central line; the samples will have markedly different blood gas levels if the catheter is in a vein.

Critical illness in pregnancy. An analysis of 20 patients admitted to a medical intensive care unit

There is a paucity of literature with regard to the need for intensive care treatment of critically ill obstetric patients. In this review, the findings from 20 obstetric patients admitted to a medical ICU (MICU) over a 40-month period were analyzed. Demographics, preexistent medical problems, diagnoses, days in the hospital and the MICU, need for mechanical ventilation, maternal and fetal mortality, and invasive procedures were reviewed. (For comparison, a limited analysis of nonobstetric admissions to the MICU over the same time period were included.) Fifty percent (10) of the patients had preexisting medical problems. Maternal mortality was 20 percent (4 patients), with a fetal mortality of 35 percent (7). In all of the maternal deaths, adult respiratory distress syndrome was present. Although mortality and the need for mechanical ventilation did not differ between the obstetric and nonobstetric patients, pulmonary artery and arterial catheters were placed at a higher rate in the obstetric patients. Critically ill obstetric patients, although younger than general MICU patients, appear to have as great a risk of dying of their critical illness and have a high infant mortality.

Intrapleural streptokinase in experimental empyema

Intrapleural streptokinase has been used in multiloculated empyemas to enhance pleural space drainage, presumably by causing fibrinolysis of the interlocular septae. We evaluated the efficacy and safety of daily administration of 10,000 U intrapleural streptokinase or equal volumes of saline to enhance resolution of experimental empyema in the rabbit pleural space. Seventy-two hours after intrapleural turpentine, 10(8) colony-forming units each of Escherichia coli, Peptostreptococcus anaerobius, and Bacteroides fragilis were injected into the sterile pleural effusion of all animals. Immediately after bacterial inoculation, and daily for 3 days, animals received 10,000 U streptokinase or saline intrapleurally. Animals that achieved a pleural fluid pH < 7.30 and either glucose < 50 mg/dl or LDH > 500 IU/L were included for data analysis. At Day 4 after bacterial inoculation, the streptokinase-treated empyemic rabbits had more pleural fluid (18.8 +/- 5.1 ml) (mean +/- SEM) than did saline-treated control animals (4.8 +/- 1.7 ml) (p = 0.015), fewer interpleural adhesions (8.2 +/- 2.7) than did saline-treated control animals (25.1 +/- 3.6) (p = 0.002), and comparable amounts of visceral and parietal pleural plaque than did saline-treated control animals (p = NS). No evidence of systemic fibrinolysis was observed at 1 h after intrapleural streptokinase administration. We conclude that intrapleural streptokinase decreases interpleural adhesion numbers but fails to reduce the amount of pleural plaque observed in experimental empyema in rabbits. The increases in pleural fluid volume observed after streptokinase administration may be due to mechanisms other than fibrinolytic activity.

Pleural effusion in lung cancer

Pleural effusions are common in the setting of lung cancer. A pleural effusion associated with lung cancer is an ominous finding, but a small percentage of patients are candidates for curative surgery. The clinician must establish whether the effusion is malignant, excluding the possibility of curative surgery; paramalignant, which may or may not exclude surgery; or whether it is unassociated with cancer. When a malignant pleural effusion is diagnosed, the clinician must decide on the most appropriate form of palliation for the symptomatic patient. In the symptomatic patient with a reasonable life expectancy and pleural fluid pH of more than 7.3, chemical pleurodesis appears to be the most effective and least morbid therapy.

Pleural macrophages differentially alter mesothelial cell growth and collagen production

Intrapleural tetracycline (TCN) results in pleural macrophage influx and pleural fibrosis; intrapleural carrageenan (CAR) induces macrophage influx without fibrosis. Because macrophage products can modulate mesothelial cell activity, we investigated the role of TCN- and CAR-induced pleural macrophages on mesothelial cell growth can collagen production. Rabbit pleural macrophages, isolated by plastic adherence 72 h after 20 mg/kg TCN or 10 mg CAR instilled intrapleurally, were cultured for 20 h. Macrophage-conditioned media (MCM) from TCN-or CAR-induce pleural macrophages (TCN MCM, CAR MCM, respectively), were added to non-confluent or confluent rat visceral pleural mesothelial cells and compared to the effects of TCN and CAR. Nonconfluent mesothelial cells were harvested 72 h later for hemacytometry cell counts. A 20-h pulse of [3H] proline (1 mu Ci, 30 Ci/mM) preceded 72-h-cell harvesting of confluent cells. Collagen content was determined in the cell fraction and cell media separately after bacterial collagenase exposure. Mesothelial cells exposed to TCN MCM were found to have decreased numbers when compared to all groups (P < 0.05) except CAR. Cell media collagen content was increased in all macrophage-conditioned-media and chemical-exposed groups compared with control, with TCN MCM having a larger increase than TCN alone (P < 0.05). We conclude that stimulated pleural macrophages release a factor(s) that alters mesothelial cell growth and collagen production and that TCN- and CAR-stimulated pleural macrophages are functionally different. These in vitro mesothelial cell alterations may be important in the genesis of TCN pleurodesis.

The clinician's perspective on parapneumonic effusions and empyema

Respondents at an interactive symposium on pleural space infections (n = 339) at the 1991 American College of Chest Physicians Annual Scientific Assembly recorded their personal management preferences for hypothetical patients with empyema. The group's preference was to treat pleural sepsis from an anaerobic multiloculated empyema by pleural decortication (49 percent); however, open thoracotomy with directed chest tube placement (22 percent), chest tube placement with intrapleural streptokinase (14 percent), placement of a single chest tube into the largest pleural loculus (8 percent), and placement of multiple small-bore catheters with computed tomographic guidance (7 percent) all had proponents. In the case of a multiloculated empyema not completely drained by a first chest tube in a nontoxic patient, the preference was drainage by a second chest tube, either a small-bore (42 percent) or a large-bore (36 percent) tube. The heterogeneity of responses suggests that prospective trials comparing treatment modalities are needed.

Pleural disease in pregnancy

Pleural effusions, pneumomediastinum, and pneumothorax are known complications of pregnancy. Although reported in small series and anecdotal case reports, the serious nature of these complications and the potential for misdiagnosis during the events of labor and delivery warrant a careful review of the available literature. In this article the incidence, clinical manifestations, and, where appropriate, therapeutic options of these disorders are discussed.

A prospective study of amylase-rich pleural effusions with special reference to amylase isoenzyme analysis

By analysis of pleural effusions from 200 patients, 25 cases of amylase-rich effusions were identified, for an overall incidence of 13 percent. Four of the 25 patients (16 percent) had evidence of pancreatitis. These patients had higher mean ratios of pleural fluid to serum amylase levels (18 +/- 6.3 [SEM] vs 4.8 +/- 1.3) compared to patients with nonpancreatic diseases (p = 0.003); all four exhibited a predominant pancreatic isoenzyme profile. Of the 21 patients with nonpancreatic amylase-rich effusions, lung cancer was the most commonly associated condition (8 patients). In 14 of the 21 patients in whom an isoenzyme profile was obtained, salivary-type amylase was predominant. Amylase-rich pleural effusions occur frequently, and pleural fluid isoamylase determination is specific for pancreatitis-associated effusions. The finding of a pleural effusion rich in salivary isoamylase should prompt an evaluation for carcinoma (particularly of lung primary), but may also be seen in other pleural inflammatory conditions.

Hamman's sign revisited. Pneumothorax or pneumomediastinum?

Louis Hamman described distinctive chest noises and emphasized their association with pneumomediastinum in 1937. However, the etiology of Hamman's sign remains incompletely defined and its association with pneumothorax underemphasized. We present a patient with pneumothorax and Hamman's sign assessed by computed chest tomography. Tomography suggested an alternate genesis of Hamman's sign; free pleural air may be cyclically channeled through a lung fissure thus creating chest sounds.

Pulmonary hypertension and human immunodeficiency virus infection. Two reports and a review of the literature

Pulmonary hypertension may be primary (idiopathic) or secondary. While the etiologies for secondary pulmonary hypertension are diverse, infection with the human immunodeficiency virus (HIV) has not been included. To date there have been 16 reported cases of pulmonary hypertension in the HIV-infected population. Plexogenic arteriopathy was the most common pathologic finding. We report two HIV-infected patients who were concomitantly found to have pulmonary hypertension with plexogenic arteriopathy. One patient had lymphocytic interstitial pneumonitis, an entity not previously associated with pulmonary hypertension. We review the 16 previous cases of pulmonary hypertension and HIV infection and discuss this association.

Pleural fluid analysis in malignant mesothelioma. Prognostic implications

Pleural fluid characteristics of 26 patients diagnosed with malignant mesothelioma over an 18-year period were reviewed and compared with those of patients with effusions due to other malignancies. Survival from time of initial thoracentesis was directly correlated with pleural pH and decreased pleural fluid/serum glucose ratios but was not related to protein or LDH concentration. Decreased pleural fluid pH was statistically related to a decreased pleural fluid/serum glucose ratio. Patients with low pH (less than 7.30) pleural effusions had statistically decreased mean survival and decreased mean pleural fluid/serum glucose ratios compared with patients with normal pH (greater than or equal to 7.30). Patients with malignant mesothelioma pleural effusions had statistically decreased mean pleural fluid pH compared with patients with other malignant pleural effusions. Decreased levels of pleural fluid pH and pleural fluid/serum glucose ratios have negative prognostic significance and probably correlate with the degree of tumor bulk affecting the pleural surface.