Cytoreductive surgery followed by intra peritoneal hyperthermic perfusion in the treatment of peritoneal surface malignancies: morbidity and mortality with closed abdomen technique.

AIMS: The purpose of this phase II study was to analyze the morbidity and mortality of cytoreductive surgery (CRS) + intraperitoneal hyperthermic perfusion (IPHP) in the treatment of peritoneal surface malignancies. PATIENTS AND METHODS: One hundred and sixty four patients (36 ovarian cancer, 32 abdominal sarcomatosis, 34 peritoneal mesothelioma, 36 pseudomyxoma peritonei, 12 gastric cancer, 8 colon adenocarcinoma and 8 from other origins) underwent 166 procedures. Two patients underwent the intervention twice due to disease relapse. The mean follow-up was 20.6 months (range: 0.4 - 91.3). The mean age was 52 years (range: 24-76). CRS was performed with peritonectomy procedures. IPHP through Closed abdominal technique was conducted with preheated (42.5 degrees) perfusate containing cisplatin+mitomycin C or cisplatin+doxorubicin for 60/90 minutes. RESULTS: grade 3/4 morbidity rate was 12.0%. Some frequent post-operatory complications were intestinal fistulas (17), respiratory (5) and abdominal bleeding (4). Multivariate analysis with logistic regression model with the backward elimination method identified carcinomatosis extension (OR: 5.3, CI95%: 1.2-24.5) as the best predictor of morbidity grade 3/4. Four patients presented grade 3/4 toxicity. Operative mortality rate was 0.6%. CONCLUSIONS: CRS+ IPHP presented acceptable morbidity 3/4 toxicity and mortality rates what support the need to be tested in prospective phase III clinical trial.

[Laboratory diagnosis of intestinal protozoan opportunistic infections in Goiânia, GO]. / Diagnóstico laboratorial dos protozoáris entéricos oportunistas em Goiânia, GO.

Cryptosporidiosis, isosporiasis, cyclosporiasis and microsporídiosis have become common in immunocompromised patients. The diagnosis of these diseases is important, because although they produce similar clinical pictures, they have a different therapeutic approach and prognostic. Seeking to evaluate the situation of the diagnosis of these parasites, the laboratories of the SUS network and health centers of the district of Goiânia-GO were mapped.

Treatment of recurrent sarcoma of the extremities by isolated limb perfusion using tumor necrosis factor alpha and melphalan.

BACKGROUND: 24-60% of patients with soft tissue sarcoma shows local recurrences after treatment of the primary tumor. The event is associated with a high incidence of macroscopic or microscopic metastases and a poor survival. Our goal is to preserve a patient's functional limb by treating such cases with isolated limb perfusion (ILP) with recombinant human tumor necrosis factor alpha (rHu TNF-alpha) and melphalan, which have demonstrated a potent antitumor activity in vivo and in vitro studies. METHODS: During the period November 1991 to November 1995, 10 patients with unresectable recurrent soft tissue sarcoma of the limb were treated by ILP at intermediate hyperthermia (40-40.5 degrees C) with rHu TNF-alpha and melphalan. Two patients also received recombinant interferon gamma (rIFN-gamma) before and during ILP. We used a range of 2-4 mg for rHu TNF-alpha and 50-100 mg of melphalan. rIFN-gamma was administered on days -2 and -1 (15 x 10(6) IU) subcutaneously and the same dose was injected in the arterial line during ILP. RESULTS: No perioperative surgical complication was observed. Local toxicity was moderate (grade I or II); general toxicity was observed in 6 patients (2 grade I and 4 grade III). Complete response was obtained in 7 cases; 2 patients had a partial response and finally 1 was a nonresponder and showed local progression, which required surgical amputation. Tumor necrosis (observed in 5 cases) was maximal in 4 patients (80-100%) and absent in the patient who had local progression. CONCLUSIONS: The results we obtained with the treatment of soft tissue sarcoma confirm the efficacy of ILP as a limb-sparing methodology for unresectable recurrences. Furthermore, rHu TNF-alpha and melphalan confirmed their antitumor activity when associated with hyperthermia. Amputation or disarticulation may be reliable as a second-choice treatment for these patients.

Pulmonary toxicity of alpha tumor necrosis factor in patients treated by isolation perfusion.

We studied pulmonary function in 22 patients affected by in-transit metastases from cutaneous melanoma and metastases from soft tissue sarcoma of the limbs who were treated with isolation perfusion in extracorporeal circulation with rTNF alpha at doses ranging from 0.5 to 4 mg/m2 in mild hyperthermia. Seventeen patients suffered from respiratory insufficiency which required assisted ventilation (7 mechanical ventilation for 1 day, 8 for 2 days and 2 patients on synchronized intermittent mandatory ventilation). Spirometric parameters recorded 7 to 15 days after treatment did not change from baseline values; in contrast, lung transfer factor for carbon monoxide significantly declined in a dose dependent fashion. These data confirm that rTNF alpha administered by isolation perfusion technique induces pulmonary side effects. Further studies are required to better define time course and reversibility of impairment in pulmonary function.

Cardiac and pulmonary effects of alpha tumor necrosis factor administered by isolation perfusion.

AIMS: We studied cardiac and pulmonary function in 22 patients affected by in transit metastases from cutaneous melanoma and metastases from soft tissue sarcoma of the limbs and treated with isolation perfusion in extracorporeal circulation with rTNF alpha at doses ranging from 0.5 to 4 mg/m2 in mild hyperthermia. PATIENTS AND METHODS: All patients experienced a septic-like shock syndrome of variable severity: this feature lasted from 24 to 72 h and was controlled by the infusion of dopamine. Seventeen patients suffered from respiratory insufficiency, which required assisted ventilation (7 cases mechanical ventilation for 1 day, 8 cases for 2 days, and 2 cases synchronized intermittent mandatory ventilation). RESULTS: Spirometric parameters recorded 7-15 days after treatment did not change from baseline values. In contrast, lung transfer factor for carbon monoxide significantly declined in a dose dependent fashion. CONCLUSIONS: Our data confirm that rTNF alpha administered by isolation perfusion technique induces systemic cardiovascular and pulmonary side effects. Further studies are required to better define time course and reversibility of impaired pulmonary function.

Treatment of in-transit metastases from cutaneous melanoma by isolation perfusion with tumour necrosis factor-alpha (TNF-alpha), melphalan and interferon-gamma (IFN-gamma). Dose-finding experience at the National Cancer Institute of Milan.

From December 1991 to July 1993, 22 consecutive patients with grade IIIA-IIIAB melanoma underwent isolation perfusion with TNF-alpha (0.5-4 mg), melphalan (10 mg/l perfused limb) and, in the first 12 cases, IFN-gamma (1.5 x 10(6) U). The first series of 12 patients received a total dosage TNF-alpha of 2-4 mg, and the second series of 10 cases received an escalating dosage of TNF-alpha (1.5-1.0-0.5 mg) and no IFN-gamma before or during surgery. The perfusion lasted 90 min and was conducted in mild hyperthermia (39-39.5 degree C muscle temperature). The results of the first series included seven patients in complete remission, four with stable disease and one case not evaluable for local toxicity. Fifty per cent of cases developed a regional relapse from 3 to 4 months after surgery. Presently with a median follow up of 10 months, five patients of this group have no evidence of disease, four are alive with disease, two died from melanoma and one died of complications likely due to treatment (multi-organ failure syndrome). In the second series, the immediate responses included seven patients in complete remission and three in partial remission; with a median follow up of 3 months, two patients developed a regional relapse, respectively, 3 and 5 months after surgery. So far our experience of perfusion with TNF-alpha has not reproduced the data reported by other investigators. Further clinical and biological findings and a longer follow-up period are needed to draw any conclusion, and a decreasing TNF-alpha dose should be carefully evaluated.

Treatment of primary or relapsing limb cancer by isolation perfusion with high-dose alpha-tumor necrosis factor, gamma-interferon, and melphalan.

BACKGROUND: Utilization of alpha-tumor necrosis factor (alpha-TNF) in clinical practice is limited by severe general side effects. Very promising results with low toxicity were reported with administration of alpha-TNF by isolation perfusion in extracorporeal circulation. METHODS: From December 1991 to November 1992, 14 patients underwent perfusion with alpha-TNF (2-4 mg, total dose), gamma-interferon (1.5 x 10(6) IU), and melphalan (10 mg/l/perfused limb). Twelve patients presented in-transit metastases of the limbs, one patient, a clear cell sarcoma of the hand, and one patient, a wide spindle cell carcinoma of the thigh. Perfusion lasted 90 minutes and was conducted in mild hyperthermia (38-40.5 degrees C, muscle temperature). RESULTS: Nine complete regressions and four stable diseases were recorded. In one case, a reliable evaluation of response was not possible for diffused tissue necrosis. Five patients relapsed or progressed locally from 3 to 4 months after surgery, five presented distant localizations from 2 to 7 months after surgery, and one died of disease 6 months after perfusion. Twelve patients are alive, seven without evidence of disease. A septic-like shock syndrome was observed in all patients and required administration of dopamine, dobutamine, or noradrenaline. One patient died 30 days after perfusion from a multiorgan-failure syndrome, likely due to alpha-TNF. The follow-up time ranges from 4 to 15 months (median, 6). CONCLUSIONS: The preliminary, impressive results reported in other series were not completely confirmed in this study adopting the same treatment scheme. Further clinical experience and biologic data are needed to state the real efficacy of the approach and to reduce the severe general toxicity consistently associated with this type of treatment.

Pulmonary toxicity of recombinant interleukin-2 plus lymphokine-activated killer cell therapy.

The aim of the present investigation was to evaluate lung toxicity in 15 patients affected by metastatic melanoma of different sites, and treated with recombinant interleukin-2 (rIL-2) plus lymphokine-activated killer (LAK) cells The treatment regimen included a first and a second course of rIL-2, separated by four consecutive daily leukaphereses. Autologous LAK cells were reinfused during the second course. Lung function was monitored before and after each rIL-2 administration. In the 12 patients who could be followed until completion of the therapy, spirometric parameters and transfer factor of the lungs for carbon monoxide (TLCO) decreased significantly during the first rIL-2 course, remained stable during leukapheresis, and declined significantly further during the second rIL-2 course. In the second phase, chest radiography documented some degree of pulmonary oedema, ranging from interstitial oedema to frank pulmonary oedema. A significant dose-dependent correlation was found between the cumulative rIL-2 dose and the decline in TLCO in the first course of therapy. Moreover, patients who developed symptomatic respiratory insufficiency (World Health Organisation grade III or IV) during the second course of therapy received a higher number of LAK cells than those who did not. The data support the hypothesis that LAK cells have an additional toxic effect on the lung.

Reappraisal of the role of liver transplantation in the treatment of hepatocellular carcinoma arising in cirrhosis.

Several retrospective analyses have recently shown the advantage of liver transplantation (OLT) for patients with hepatocellular carcinoma (HCC) at early tumor stages. Preliminary results of a prospective series of OLT for unresectable small HCC arising in cirrhosis are reported. Eighteen out of 22 patients (82%) are alive without evidence of HCC recurrence after a median follow-up of 11 months.

[Use of buprenorphine after right hepatectomy]. / Impiego della buprenorfina dopo intervento di epatectomia destra.

Ten patients who underwent surgery (5 right hepatectomy and 5 colectomy) for cancer participated in a clinical controlled study. They were treated with buprenorphine (i.v. slow infusion) to relieve postsurgical pain. We found an increased urinary excretion of this drug in patients who underwent hepatectomy as compared with patients who underwent colectomy. However no differences in the occurrence of side-effects and/or in the therapeutic effect were observed between the two groups. We conclude that buprenorphine can be effectively and safely used also in patients with a resection of liver parenchyma.

[Functional changes in the biliary system following extrahepatic biliary obstruction]. / Alterazioni funzionali del sistema biliare secondarie ad ostruzione biliare extraepatica.

To assess the potential structural changes of the biliary tree and liver in patients with extrahepatic biliary obstruction, the resected specimens of 20 patients operated for benign biliary stricture were evaluated by means of immunocytochemical and histological methods. Furthermore, liver biopsies were taken for the same purposes. The results showed that in the dilated segment of the hepatic duct proximal to the stricture, innervation was greatly reduced or completely absent with associated advanced morphological and histological changes and high intrabiliary pressure levels. Similar findings were observed in the liver biopsies, too. These biopsies showed advanced morphological and histological changes associated with reduced innervation. By contrast, the nondilated segment of the hepatic duct, distal to the obstruction, showed normal innervation, normal morphology and histology and normal levels of intrabiliary pressure. The present study provides evidence that in cases of extrahepatic biliary obstruction, there are advanced pathological changes in the biliary tree associated with innervation impairment. These structural changes are associated with functional changes in both the liver and the biliary tree. Such functional changes represent a threat to the patient, particularly if major surgery is required. Increased biliary pressure appears to be a major cause of the development of these changes. Biliary drainage, either surgical or endoscopic, is indicated as the only alternative to reduce intrabiliary pressure and to contribute to a reversal of these structural and functional changes.

[Muciparous cells and endocrine cells of the gallbladder epithelium in patients with uncomplicated cholelithiasis]. / Cellule mucipare e cellule endocrine dell'epitelio della colecisti in pazienti con colelitiasi non complicata.

In this study the authors have investigated the different morphofunctional features of the gallbladder mucosa in patients with uncomplicated cholelithiasis. Histological changes, type and distribution of endocrine and mucin-producing cells were characterized by immunocytochemistry and mucin histochemistry. The authors attempted to correlate these findings to the number and size of gallbladder stones as well as type of bacteria present in the bile. The results indicate that, despite similar clinical parameters, a wide range of histological changes may occur in the gallbladder mucosa of these patients. Moreover, the presence of some endocrine and mucin-producing cell types in the so called "pyloric metaplasia" led the Authors to hypothesize that the latter may be a trivial event.

Granuloma anular gigante en napa, factor de error diagnostico / Giant anular granuloma in layer, diagnostic error factor

Con el objetivo de recordar la forma de granuloma anular gigante en napa se presentan dos observaciones con diagnóstico erróneo de lepra indeterminada y sarcoidosis respectivamente. Esta forma clínica ha sido motivo de atención bibliográfica desde 1930 a 1950. La tendencia actual de la misma es buscar las diferencias histológicas entre el granuloma anular localizado y el generalizado, del cual el gigante en napa es sólo una de sus formas con un aspecto característico. Su imagen clínica debe ser recordada para orientar a la histopatología (AU)

Granuloma anular gigante en napa, factor de error diagnostico / Giant anular granuloma in layer, diagnostic error factor

Con el objetivo de recordar la forma de granuloma anular gigante en napa se presentan dos observaciones con diagnóstico erróneo de lepra indeterminada y sarcoidosis respectivamente. Esta forma clínica ha sido motivo de atención bibliográfica desde 1930 a 1950. La tendencia actual de la misma es buscar las diferencias histológicas entre el granuloma anular localizado y el generalizado, del cual el gigante en napa es sólo una de sus formas con un aspecto característico. Su imagen clínica debe ser recordada para orientar a la histopatología

FMLP-induced arachidonic acid release, phospholipid metabolism, and calcium mobilization in human monocytes. Regulation by cyclic AMP.

Radiolabeled human peripheral blood monocytes released [3H]arachidonic acid upon challenge with the calcium ionophore A23187 (10 microM), or f-Met-Leu-Phe (FMLP, 1 microM). Chromatographic analysis of [3H]arachidonic acid labeled phospholipids showed that stimulation by FMLP reduced the amount of labeled phosphatidylcholine exclusively. Treatment of the monocytes with 10(-3) M dibutyryl cyclic AMP (d-cAMP) or 5 X 10(-4) M isobutylmethylxanthine (IBMX) substantially inhibited [3H]arachidonic acid release (30%) and depletion from labeled phosphatidylcholine (PC) in FMLP--but not calcium ionophore--stimulated cells. Using the fluorescent probe Indo-1, the FMLP-induced cytosolic calcium increase was unaffected by 10(-3) M dibutyryl cyclic AMP. The results suggest that FMLP-stimulated phospholipase activity is regulated by cyclic AMP, but not by depressing receptor-medicated increases in cytoplasmic free calcium.

Phospholipid and arachidonic acid metabolism in zymosan-stimulated human monocytes: modulation by cAMP.

Receptor-ligand interaction in mononuclear phagocytes is intimately linked to alterations in membrane phospholipids and release of arachidonic acid (AA). In addition, synthesis of bioactive lipids from released AA can result in further modification of cell responses. Upon challenge with opsonized zymosan, [3H]-arachidonic acid ([3H]-AA)-labeled human monocytes released 25 +/- 2% of their incorporated radiolabel within 30 min. Pretreatment of the monocytes with 5 X 10(-4) M isobutylmethylxanthine (IBMX) or 1 X 10(-3) M dibutyryl cyclic AMP (d-cAMP) inhibited total [3H]-AA release in the presence of zymosan by 47% and 42%, respectively. Analysis of incorporated [3H]-AA in cellular phospholipid pools indicated that significant amounts of label were lost from both phosphatidylcholine (PC) and phosphatidylinositol (PI) during zymosan stimulation. Treatment with d-cAMP substantially inhibited the loss of label from PC, but had no affect on PI. HPLC analysis of cell supernatants from zymosan-treated cells indicated that 5-HETE was the predominant metabolite generated from [3H]-AA, and its production was depressed during treatment with d-cAMP. Phospholipase activity in human monocyte homogenates was not effected by d-cAMP or IBMX at the highest concentrations used, whether these were added directly to the homogenate or by pretreatment of whole cells, demonstrating that inhibition required an intact cell. These results suggest that human monocytes exposed to opsonized zymosan release AA via two mechanisms and that modulation by cAMP is indirectly effecting a phospholipase directed towards PC.

Stimulus-specific induction of phospholipid and arachidonic acid metabolism in human neutrophils.

Phospholipid remodeling resulting in arachidonic acid (AA) release and metabolism in human neutrophils stimulated by calcium ionophore A23187 has been extensively studied, while data obtained using physiologically relevant stimuli is limited. Opsonized zymosan and immune complexes induced stimulus-specific alterations in lipid metabolism that were different from those induced by A23187. [3H]AA release correlated with activation of phospholipase A2 (PLA2) but not with cellular activation as indicated by superoxide generation. The latter correlated more with calcium-dependent phospholipase C (PLC) activation and elevation of cellular diacylglycerol (DAG) levels. When cells that had been allowed to incorporate [3H]AA were stimulated with A23187, large amounts of labeled AA was released, most of which was metabolized to 5-HETE and leukotriene B4. Stimulation with immune complexes also resulted in the release of [3H]AA but this released radiolabeled AA was not metabolized. In contrast, stimulation with opsonized zymosan induced no detectable release of [3H]AA. Analysis of [3H]AA-labeled lipids in resting cells indicated that the greatest amount of label was incorporated into the phosphatidylinositol (PI) pool, followed closely by phosphatidylcholine and phosphatidylserine, while little [3H]AA was detected in the phosphatidylethanolamine pool. During stimulation with A23187, a significant decrease in labeled PI occurred and labeled free fatty acid in the pellet increased. With immune complexes, only a small decrease was seen in labeled PI while the free fatty acid in the pellets was unchanged. In contrast, opsonized zymosan decreased labeled PI, and increased labeled DAG. Phospholipase activity in homogenates from human neutrophils was also assayed. A23187 and immune complexes, but not zymosan, significantly enhanced PLA2 activity in the cell homogenates. On the other hand, PLC activity was enhanced by zymosan and immune complexes. Stimulated increases in PLC activity correlated with enhanced superoxide generation induced by the stimulus.

Structural requirements for chemotactic activity of leukotriene B4 (LTB4).

LTB4 (5s, 12R dihdroxy-6, 14-CIS-8, 10-trans-eicosatetraenoic acid) formed in activated neutrophils by lipoxygenation of arachidonic acid is an extremely potent chemotaxin. We examined structural requirements for chemotactic and aggregatory activity of the ligand using synthetic LTB4 and several of its isomers. Additionally we examined the potency of two analogs, nor- and homo-LTB4. Dose response curves for neutrophil chemotaxis to these compounds were obtained using a modified Boyden chamber. The mean distance cells moved into the filter was determined after 30 minutes. Peak chemotactic activity of LTB4 was at 10(-7)M. At higher concentrations, chemotactic activity was decreased. The shape of the dose response curve was similar to that of FMLP except that maximum chemotaxis to LTB4 was consistently greater than chemotaxis to FMLP. A mixture of the two epimers at c-5 and c-12 shifted the response curve to the right but did not lower maximum activity. Increasing or decreasing the chain by one carbon between the first hydroxyl group and the carboxyl group also shifted the response curve to the right without lowering maximal activity. Changing the 6 double bond from cis to trans has a greater effect. Activity was only detectable at high concentrations and maximum activity achieved was less than 50% that of LTB4. Thus the chain length between the carboxyl and C-5 hydroxyl groups, the c-5 and c-12 absolute stereochemistry and the stereochemistry of the delta6 double bond are all important structural features for chemotactic activity with delta6 stereochemistry apparently having the greatest contribution. The relative potencies of these compounds in inducing aggregation were comparable to their chemotactic potencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Neutrophils may directly synthesize both H2O2 and O2- since surface stimuli induce their release in stimulus-specific ratios.

Many stimuli induce neutrophils to undergo an oxidative burst and generate toxic oxygen metabolites. The major products are O2- and H2O2, the latter being presumed to arise by spontaneous dismutation of the former. If H2O2 were indeed derived exclusively from released O2- according to the equation 2O2- + 2H+----H2O2 + O2, one would expect that relationship to be reflected in the ratio of the two metabolites detectable in the extracellular mileu of stimulated neutrophils. A second corollary is that H2O2 should not form when cytochrome c is present to scavenge O2- before it can dismutate. Although H2O2 cannot be measured directly in the presence of cytochrome c because it is consumed in reoxidizing reduced cytochrome c, its presence can be detected indirectly by the ability of catalase to improve the apparent yield of reduced cytochrome c. We found that the relative amounts of extracellular H2O2 and O2- that could be measured in the environment of stimulated neutrophils varied with the stimulus and that catalase protected reduced cytochrome c from H2O2 oxidation when some stimuli were used but not with others. For example, the ratio of O2- to H2O2 produced by neutrophils exposed to PMA was about 2:1, the expected result if H2O2 were derived from O2-. However when cytochalasin B was added to the cells before the stimulus, the yield of H2O2 was reduced but not the yield of O2-. When cells were allowed to settle and spread on tissue culture plastic they produced equimolar amounts of O2- and H2O2. Coating the plastic with IgG doubled cytochrome c reduction without effecting H2O2. In contrast, coating with albumin reduced H2O2 without effecting cytochrome c reduction. Soluble IgG aggregates induced production of mostly O2- whereas immune complexes resulted in release of both metabolites. FMLP and A23187 were similar to the soluble IgG aggregates in their effects and induced release of proportionately more O2- than H2O2. The addition of catalase to the cytochrome c solution improved the yield of reduced cytochrome c when PMA or IgG was used to stimulate the cells but not when FMLP was used. These and other data suggest that H2O2 release is not a linear function of the amount of O2- generated and that either a variable fraction of O2- spontaneously dismutates to H2O2 or the neutrophil NADPH oxidase, in a manner analogous to xanthine oxidase, is capable, under some circumstances, of producing H2O2 as well as O2-.(ABSTRACT TRUNCATED AT 400 WORDS)

Surface contact inhibits neutrophil superoxide generation induced by soluble stimuli.

Human neutrophils in suspension undergo a metabolic burst and generate reactive O2- metabolites upon exposure to many soluble and particulate stimuli. They can also be stimulated to produce O2- when in contact with surfaces. We found that when neutrophils were allowed to settle into protein-coated surfaces the amount of O2- they generated varied with the nature of the protein: IgG greater than bovine serum albumin greater than plastic greater than gelatin greater than serum greater than collagen. However, when polymorphonuclear leukocytes were permitted to settle onto a surface and then were stimulated with either phorbol myristate acetate or N-formyl-methionyl-leucyl-phenylalanine the O2- response was greatly diminished compared to control cells that were exposed to the stimulus in suspension. In contrast, superoxide production in response to the particulate stimulus opsonized zymosan was similar in both suspended and settled neutrophils. The degree of inhibition was not related to the degree of adherence since the diminished response occurred with all of the surfaces tested and in the presence of cytochalasin B. Onset of inhibition was very rapid as was recovery when cells were resuspended. Whereas production of O2- was greatly inhibited by surface contact, release of lysosomal enzymes was only slightly affected. The effect of surface contact did not appear to be mediated via activation of adenylate cyclase since the combination of a phosphodiesterase inhibitor and exogenous dibuteryl cyclic adenosine monophosphate did not inhibit phorbal myristate acetate O2- production, but surface contact did. These data indicate that surface contact such as would occur during diapedesis and chemotaxis profoundly alters neutrophil behavior by an unknown mechanism and imply that observations made on polymorphonuclear leukocytes in suspension cannot be generalized to polymorphonuclear leukocytes in tissue.