Cigarette smoke: protection of alveolar macrophages by glutathione and cysteine.

Phagocytosis of bacteria by rabbit alveolar macrophages is inhibited quantitatively by cigarette smoke in vitro. This phagocytoxic effect was abolished by addition of 0.2 to 0.4 micromole of glutathione or cysteine per milliliter of cigarette smoke. Serum protein was required to obtain both the toxic effect of the smoke and the protective action of the sulfhydryl compounds. The protective role of the sulfhydryl agents suggests an oxidant action of the cigarette smoke on these pulmonary cells.

Deforestation history of the eastern rain forests of madagascar from satellite images.

Madagascar is biologically one of the richest areas on Earth, and its plants and animals are among the most endangered. Satellite images and vegetation maps based on earlier aerial photographs were used to determine the extent of eastern rain forests in Madagascar and to monitor the rate of deforestation over a 35-year period. In 1985, 3.8 million hectares of rain forest remained, representing only 50 percent of the 7.6 million hectares existing in 1950 and 34 percent of the estimated orignal extent (11.2 million hectares). Between 1950 and 1985, the rate of deforestation averaged 111,000 hectares per year. Deforestation was most rapid in areas with low topographic relief and high population density. If cutting of forests continues at the same pace, only forests on the steepest slopes will survive the next 35 years.

Defect in intracellular killing of Staphylococcus aureus within alveolar macrophages in Sendai virus-infected murine lungs.

Bacterial multiplication associated with virus infections is related to defects in in situ bactericidal (phagocytic) mechanisms of the lung. To determine whether the phagocytic defect was in bacterial ingestion and/or intracellular digestion, mice were infected with a sublethal dose of aerosolized Sendai virus and challenged 7 days later with a finely dispersed aerosol of Staphylococcus aureus. Groups of uninfected and virus-infected mice were sacrificed at 0, 6, 12, and 24 h after challenge, the lungs were perfused with formalin in situ, and the intra- or extracellular location of the bacteria was determined histologically. At 0 h, 49% and 51% of the staphylococci had an intracellular location in virus and nonvirus-infected lungs, respectively. With time, decreasing numbers of staphylococci were observed within the phagocytic cells of nonvirus-infected lungs, mostly as single organisms or in small clusters of less than four. In contrast, in focal area of virus-infected lungs, increasing numbers of phagocytic cells showed clumps of more than 25 bacteria/cell. These data demonstrate that virus-infected suppression of pulmonary antibacterial activity against S. aureus is related primarily to defects in intracellular processing mechanisms.

Immune enhancement of pulmonary bactericidal activity in murine virus pneumonia.

Bacterial multiplication in the lung associated with murine Sendai virus pneumonia is caused by virus-induced defects in pulmonary bactericidal mechanisms. The nature of this effect has been studied in animals immunized against the challenge bacteria. Mice were immunized against Proteus mirabilis by intraperitoneal inoculation and by aerosol inhalation. After the development of immunity, mice were infected aerogenically with 10(4) TCID(50) of Sendai virus. 7 days later, during the height of the bronchial inflammation and pulmonary consolidation, the mice were challenged with an aerosol of viable (35)S-labeled Proteus mirabilis or (32)P-labeled Staphylococcus aureus.Nonimmunized virus-infected animals showed marked impairment of pulmonary bactericidal activity with subsequent multiplication of the bacterial strain in the case of Proteus mirabilis. Immunized nonvirus-infected animals showed enhancement of pulmonary bactericidal activity for the homologous and heterologous strains in comparison with nonimmunized animals. Virus-infected animals immunized by aerosol showed enhanced bactericidal activity against the homologous but not the heterologous bacterial strain. Neither virus infection nor immunization had a significant effect on the transport of particles in the lung. The data demonstrated that the bacterial multiplication associated with the virus pneumonia was prevented by preceding immunization against the homologous challenge organism. The data suggest a mechanism for controlling bacterial multiplication associated with virus pneumonias.

The effect of Sendai virus infection on bactericidal and transport mechanisms of the murine lung.

Pulmonary virus infections predispose to bacterial infections in the lung. The mechanism of this effect was studied by quantitative comparison of the effects of airborne acute viral infection on pulmonary transport vs. in situ bactericidal mechanisms in mice. Animals infected by aerosol with 10(4) TCID(50) of Sendai virus developed pathologic pulmonary changes of interstitial pneumonitis, bronchial epithelial desquamation, and peribronchial mononuclear cell infiltration 7 days later. At that time, the mice were challenged with an aerosol of viable (32)P-labeled Staphylococcus aureus. Pulmonary bactericidal activity and physical transport by the lung were determined by the determination of viable staphylococcal and (32)P radiotracer counts respectively at 4, 24, 48, and 72 hr after bacterial challenge. Infected mice showed a significant decrease from normal in the rate of reduction of viable bacterial counts in the first 4 hr after challenge followed by a proliferation of the staphylococci. By contrast, radiotracer removal rates at 4 and 24 hr were similar in infected and noninfected mice. There was a small but significant retention of (32)P in the lungs of the infected animals at the later periods. These data demonstrate that bacterial multiplication associated with virus infection of lungs is related to defects in in situ bactericidal (phagocytic) mechanisms rather than transport mechanisms of the lung, despite histologic evidence of extensive destruction of bronchial-ciliated epithelium.

Antibacterial mechanisms of the urinary bladder.

THE DISAPPEARANCE OF BACTERIA FROM THE NORMAL URINARY BLADDER IS APPARENTLY A FUNCTION OF TWO HOST DEFENSE MECHANISMS: the mechanical clearance of organisms by voiding, and the antibacterial activity of the bladder wall. This study quantified the relative contribution of each of these mechanisms to the resistance of the bladder to bacterial infection.(32)Phosphorus-labeled E. coli. S. aureus, and P. mirabilis were each injected into the urinary bladders of unanesthetized female guinea pigs. At intervals after voiding, the bladders were removed, washed, homogenized, and assayed for residual radioactivity and viable bacteria. Mechanical clearance was measured by the changes in total radioactive count. Antibacterial activity was quantified by comparing the bacterial to radioactive ratios of the original bacterial inoculum with similar ratios in the bladder homogenates. More than 99.9% of the bladder inoculum was rapidly excreted and about 0.1% (10(4)-10(5)) organisms remained attached to the bladder wall. Of those E. coli attached to the bladder, rapid sequential reduction in viability occurred and reached a level of 85% loss at 30 min after inoculation. 4 hr after challenge, less than 10% of those organisms still attached to the bladder mucosa remained viable. P. mirabilis was handled with equal facility, but S. aureus showed a reduction in viability of only 46% at 1 hr and 67% at 4 hr after inoculation. 6 hr after infection with S. aureus, 6 of 12 guinea pig bladders showed multiplication of the organisms still attached to the bladder wall; only 1 of 12 animals challenged with E. coli had comparable multiplication. The mechanism whereby the bladder wall kills bacteria is unclear, but it did not appear to be related to an antibacterial activity of urine, clumping of organisms on bladder mucosa, phagocytosis by leukocytes, or serum levels of bactericidal antibody. Although it is clear that the bladder exhibits intrinsic antibacterial properties, the role of this defense mechanism in the pathogenesis of urinary tract infection requires further clarification.

Do clinical and formal assessments of the capacity of patients in the intensive care unit to make decisions agree?

BACKGROUND: The complex environment and technology of intensive care unit (ICU) care may impair the ability of patients to participate in medical decision making or give informed consent. We studied the agreement of the intuitive assessments of residents and nurses of ICU patients' cognition, judgment, and decision-making capacity, and whether those assessments agreed with abbreviated formal mental status testing. METHODS: Using a prospective survey case study, we assessed 200 English-speaking patients within 24 hours of their ICU admission. Formal assessment of cognition, judgment, and insight was performed by a research assistant. We obtained independent intuitive ratings by nurses and residents of patient cognition, judgment, and ability to participate in medical decision making or give informed consent. RESULTS: Residents' and nurses' assessment of cognition and judgment showed a high degree of agreement with weighted ks of greater than 0.76. Assessments of cognition by residents and nurses agreed with Folstein Mini-Mental State Examination in 70% and 73.6% of cases, respectively. Forty percent of the population had an unimpaired Mini-Mental State Examination score of greater than 23, and an additional 12% of the subjects were mildly impaired with scores of 20 to 23. When asked whether they would approach patient or family for consent for an invasive procedure, nurses and physicians said they would request informed consent from 66% and 62% of the patients, respectively. CONCLUSIONS: Residents and nurses caring for patients newly admitted to the ICU agree in their assessment of cognition, judgment, and capacity to participate in medical decision making, and are not unduly influenced by ventilator status. Their assessments correlate highly with abbreviated formal mental status testing.

Treatment with an oral proteinase inhibitor slows gastric emptying and acutely reduces glucose and insulin levels after a liquid meal in type II diabetic patients.

OBJECTIVE: To determine whether an oral trypsin/chymotrypsin inhibitor, POT II, will delay the rate of gastric emptying in recently diagnosed type II diabetic patients and improve their postprandial metabolic parameters. RESEARCH DESIGN AND METHODS: Two gastric emptying studies were performed on each of six type II diabetic patients. During one study, the patient ingested a glucose/protein solution, and during the other study, the patient ingested the same glucose/protein solution with the addition of 1.5 g of POT II, a putative stimulant of cholecystokinin (CCK) release. Each patient served as their own control subject. Each of the two oral solutions were administered to the patients in a counter-balanced order separated by at least 1 week. RESULTS: Serum insulin, plasma glucose, plasma gastric inhibitory polypeptide (GIP) values, and the rate of gastric emptying were all significantly (P < 0.05) decreased over the 2-h testing period when POT II was added to the oral glucose/protein meal. The area under the curve above baseline for glucose with POT II was 75% of the glucose value without POT II. The area under the curve above baseline for insulin with POT II was 68% of the value without POT II. Plasma CCK was significantly increased by POT II 15 min postprandially. CONCLUSIONS: A trypsin/chymotrypsin inhibitor, POT II, can delay the rate of gastric emptying, and decrease postprandial plasma glucose levels, GIP levels, and serum insulin levels in type II diabetic patients diagnosed recently. Delay of gastric emptying in diabetic patients may provide a unique or adjunctive approach to the treatment of type II diabetes.

Rapid gastric emptying of a solid pancake meal in type II diabetic patients.

OBJECTIVE: To estimate the rate of gastric emptying of a solid pancake carbohydrate meal in recently diagnosed asymptomatic type II diabetic patients compared with nondiabetic control subjects. RESEARCH DESIGN AND METHODS: Gastric emptying studies using radiolabeled meals were performed on eight recently diagnosed asymptomatic diabetic patients and on eight sex-, BMI- and age-matched nondiabetic control subjects. Although a liquid protein drink was administered along with the pancake meal, the radioactivity was adherent to only the pancake portion of the meal. Plasma glucose and serum insulin levels were measured in fasting and postprandial blood samples collected at 15-min intervals up to 120 min after ingestion of the mixed nutrient meal. RESULTS: The average gastric half-emptying time (time it takes for one-half of the meal to empty) was significantly more rapid for the diabetic patients (45.3 +/- 4.8 min) when compared with the nondiabetic control subjects (60.4 +/- 5.1 min; P = 0.05). The serum insulin concentrations were not statistically different between the two groups. Plasma glucose values were significantly higher in the diabetic patients compared with the nondiabetic control subjects. CONCLUSIONS: Type II diabetic patients with no clinical evidence of neuronal dysfunction have a significantly more rapid rate of gastric emptying of a solid high-carbohydrate meal when compared with nondiabetic control subjects.

Role of secretin in basal and fat-stimulated pancreatic secretion in conscious rats.

The role of endogenous secretin in basal and fat-stimulated pancreatic exocrine secretion was investigated in conscious rats. Rats were prepared with chronic fistulas draining bile and pancreatic juice, which was collected and returned to the duodenum at all times. Six days postoperative rats were fasted overnight, and pancreatic protein and fluid secretion were monitored for 3 h under basal conditions (0.15 M NaCl, intraduodenally) and during 2 h of intraduodenal infusion of a 20% triglyceride emulsion (Liposyn). Solutions were infused at 4.6 ml/h. Rats received a single bolus injection of 0.1 ml antisecretin serum or normal rabbit serum starting in the second hour of the basal period, and the effect on basal and fat-stimulated pancreatic protein and fluid secretion was determined. Antisecretin serum significantly inhibited basal interdigestive pancreatic protein and fluid secretion by 43% and 36%, respectively. Infusion of 20% fat emulsion stimulated a 2.1-fold increase in pancreatic protein and fluid secretion. The stimulation of both protein and fluid secretion was significantly inhibited by 60% by antisecretin serum. Plasma secretin after 2 h of fat infusion was 17.7 +/- 1.8 pM and was greatly reduced by the presence of secretin antiserum. The results support the hypothesis that secretin released by fatty acids is an important mediator of the pancreatic protein and fluid secretory response to dietary fat in the rat.

Distribution and localization of a novel cholecystokinin-releasing factor in the rat gastrointestinal tract.

The purpose of this study was to examine the distribution and localization of an intestinal cholecystokinin (CCK)-releasing factor, called luminal CCK-releasing factor (LCRF), in the gastrointestinal tract and pancreas of the rat. RIA analysis indicates that LCRF immunoreactivity is found throughout the gut including the pancreas, stomach, duodenum, jejunum, ileum, and colon with the highest levels in the small intestine. Immunohistochemistry analysis shows LCRF immunoreactivity staining in intestinal villi, Brunner's glands of the duodenum, the duodenal myenteric plexus, gastric pits, pancreatic ductules, and pancreatic islets. These results indicate potential sources for secretagogue-stimulated release of luminal LCRF and support the hypothesis that LCRF is secreted into the intestinal lumen to stimulate CCK release from mucosal CCK cells.

Different subtypes of alpha 1A-adrenoceptor mediating contraction of rat epididymal vas deferens, rat hepatic portal vein and human prostate distinguished by the antagonist RS 17053.

1. The alpha 1-adrenoceptor subtype mediating contraction of the rat hepatic portal vein to phenylephrine was characterized by use of competitive antagonists previously shown to have selectivity between the expressed alpha 1-subtype clones. Prazosin competitively antagonized the phenylephrine contractions with a pA2 value of 9.2, as did WB 4101 (pA2 9.4), 5-methyl urapidil (pA2 8.6), indoramin (pA2 8.4) and BMY 7378 (pA2 6.5). 2. The pA2 values on the rat portal vein correlated highly with their previously published pA2 values for the alpha 1A-adrenoceptors mediating contraction of the rat epididymal vas deferens and human prostate and poorly with those for the alpha 1B- and alpha 1D-adrenoceptors mediating contraction of the rat spleen and aorta, respectively. The antagonist pA2 values on the rat portal vein correlated highly with their previously published pK1 values for the expressed alpha 1a-clone and poorly with those for the expressed alpha 1b- and alpha 1d-clones. Therefore the results show that contraction of the rat portal vein to phenylephrine is mediated by alpha 1A-adrenoceptors. 3. The novel alpha 1-adrenoceptor antagonist RS 17053 had a relatively high affinity for the alpha 1A-adrenoceptors mediating contraction of the rat epididymal vas deferens (pA2 9.5) compared with the alpha 1B-adrenoceptors in the rat spleen (pA2 7.2) or the alpha 1D-adrenoceptors in the rat aorta (pKB 7.1), in agreement with its selectivity for the expressed alpha 1a-clone. However, RS 17053 had over 100 fold lower affinity for the alpha 1A-adrenoceptors mediating contraction of the rat portal vein (pKB 7.1) and human prostate (pKB 7.1) compared with its affinity for the alpha 1A-adrenoceptors in the rat epididymal vas deferens or the expressed alpha 1a-clone. 4. The difference in affinity of RS 17053 between the rat epididymal vas deferens and rat portal vein cannot be explained by a species difference in the receptor. Therefore RS 17053 may distinguish between subtypes of the alpha 1A-adrenoceptor in the rat portal vein and human prostate compared with those in the rat epididymal vas deferens or the expressed alpha 1a-clone.

Diagnosis of pneumonia due to Pneumocystis by subsegmental pulmonary lavage via the fiberoptic bronchoscope.

To assess the accuracy of pulmonary lavage in diagnosing pneumonia due to Pneumocystis, we used animals as a model and then prospectively studied 33 immunosuppressed adults with diffuse pulmonary infiltrates. In rats treated with cortisone, Pneumocystis organisms could be found in the effluent from lavage as early as in sections of pulmonary tissue, and the effluent from lavage remained diagnostic throughout the ten weeks of observation. Subsegmental lavage in adult patients was performed through the wedged fiberoptic bronchoscope. Pneumocystis organisms were demonstrated in seven patients by lavage, and no false-negative results were recorded. Pneumocystis organisms were readily identified among the sheets of alveolar macrophages seen in smears of the effluent from lavage that were stained with methenamine silver. Subsegmental lavage via the fiberoptic bronchoscope is an accurate and safe technique for establishing the diagnosis of pneumonia due to Pneumocystis in patients whose respiratory embarrassment or thrombocytopenia makes biopsy of the lung hazardous.

Feedback inhibition of cholecystokinin secretion by bile acids and pancreatic proteases.

Feedback inhibition of CCK release by bile acids and pancreatic proteases is well established in the rat. The question of whether these mechanisms are important in humans has not been completely resolved, but current evidence strongly suggests that feedback regulation of CCK release by bile acids is present in humans and is physiologically significant, whereas the existence and importance of feedback regulation of CCK release by pancreatic proteases in humans are still highly controversial.

Bioactivity of intraduodenally and intravenously infused fragments of luminal cholecystokinin releasing factor (LCRF).

A luminal cholecystokinin releasing factor (LCRF), has been purified from intestinal secretion and found to have a mass of 8136 daltons. The amino-terminal 41 residues have been sequenced. Previous studies showed that intraduodenal infusion of the synthetic amino-terminal 35 amino acid peptide, LCRF1-35 significantly stimulated pancreatic protein and fluid secretion in conscious rats, but the peptide did not stimulate amylase release from isolated, dispersed pancreatic acini. In the present study, several fragments of LCRF were synthesized and tested for CCK-releasing activity (pancreatic protein secretion) to determine whether shorter fragments of LCRF exhibit the characteristic biological activity of native LCRF and synthetic LCRF1-35. Compounds tested were LCRF1-41, LCRF1-35, LCRF1-65 and LCRF11-25. Of the fragments shorter than LCRF1-35, only LCRF11-25 but not LCRF1-6 had significant CCK releasing activity. LCRF1-41 was equivalent to LCRF1-35 in potency and efficacy. Intravenous and intraduodenal infusion of LCRF1-35 elicited nearly identical dose-response curves.

Role of gastric juice in feedback regulation of rat pancreatic secretion by luminal proteases.

The role of gastric juice in the intestine on the pancreatic secretory response to intraduodenal infusion of trypsin inhibitors or to diversion of bile and pancreatic juice from the intestine was studied in conscious rats with pylorus ligation and gastric juice drainage. In absence of gastric juice in the intestine, diversion of bile and pancreatic juice from the intestine stimulated pancreatic secretion, but the incremental protein and fluid secretory responses to diversion of bile and pancreatic juice were increased approximately 2.9-fold and 2.5-fold, respectively, by intraduodenal infusion of HCl (60 microEq/h). Intraduodenal infusion of HCl (240 microEq/h) had no effect on the pancreatic secretory response to infusion of lima bean trypsin inhibitor (20 mg). These results support the hypothesis that the inhibitory effect of atropine on the pancreatic secretory response to diversion of pancreatic juice or bile and pancreatic juice is secondary to inhibition of gastric acid secretion. The lack of effect of HCl on the pancreatic response to trypsin inhibitor contradicts the hypothesis that acid in the intestine is important or necessary for the feedback response to loss of intraluminal protease activity. It is proposed that acid in the intestine augments the pancreatic response to diversion of pancreatic juice or bile and pancreatic juice by reducing intraluminal pH and thereby inactivating residual pancreatic proteases.

Pancreatic hypersecretion in the jejunal-bypass rat.

We diverted bile and pancreatic juice from jejunal blind loops of different lengths in conscious rats to see if the pancreatic secretory response was dependent on the length of the jejunal blind loop. Short-term bile and pancreatic juice diversion from a short jejunal blind loop, representing only 8-10% of the total length of the small intestine, stimulated a significant increase in pancreatic exocrine secretion. Short-term bile and pancreatic juice diversion from jejunal blind loops of increasing length resulted in a progressive decrease in the pancreatic secretory response to diversion (i.e., there appears to be a length-dependent inhibition of the pancreatic secretory response to short-term bile and pancreatic juice diversion from the jejunum). Cholinergic receptor blockade with atropine eliminated this length-dependent inhibition of pancreatic exocrine secretion during short-term bile and pancreatic juice diversion. In contrast to what was observed with short-term bile and pancreatic juice diversion, there was a length-dependent increase in pancreatic secretion during long-term bile and pancreatic juice diversion. The jejunal-bypass rat model can facilitate the investigation of the intestinal mechanisms mediating feedback regulation of pancreatic exocrine secretion.

Secretion of protein, fluid, and immunoreactive somatostatin in rat pure pancreatic juice: adaptation to chronic cerulein and secretin treatment.

These studies were undertaken to assess the effects of chronic administration of cerulein plus secretin, every 8 h for 10 days on fluid, protein, and somatostatin-like immunoreactivity (SLI) outputs in rat pancreatic juice. Pancreatic secretion was studied with conscious, cannulated rats, during infusion of precollected pancreatic juice to the rat intestine. Volume output reached a plateau of 5.2 ml/210 min after 3 days of treatment. Protein secretion steadily increased up to 218 mg/210 min after 5 days, decreased to 118 mg/210 min by day 7, and rose again to 281 mg/210 min after 10 days. The SLI release increased stepwise with a first plateau after 3 days at 493 ng/210 min; values between 983 and 562 ng/210 min were observed between days 4 and 7 with a third plateau at 1,887 ng/210 min between days 8 and 10. Peak levels of volume and protein occurred between 30 and 90 min following each daily stimulation. In the early days SLI output reached its peak 3.5 h after stimulation, whereas at the end of treatment, synchronous secretion of protein and SLI was observed. These data indicate that important modifications occur in the rate of secretion of protein and SLI in the pancreatic juice in the course of chronic administration of cerulein plus secretin.

Lack of effect of cerulein on pancreatic growth of rats fed a low-protein diet.

The effect of dietary protein deficiency and protein concentration of the diet on the pancreatic trophic response to a CCK analogue (cerulein) were studied. Rats were fed for 14 days with semipurified diets containing 5, 30, or 60% casein. During the final 4 days, they received 2 micrograms/kg cerulein or gelatin vehicle subcutaneously three times/day, and the effects on pancreatic weight and pancreatic content of protein, RNA, DNA, amylase, and chymotrypsin were determined. Cerulein failed to increase significantly any pancreatic parameter in rats fed 5% casein, while stimulating significant increases in almost all parameters in rats fed 30 and 60% casein diets. In the absence of cerulein treatment, increases in dietary protein levels caused progressive increases in all pancreatic growth parameters with the exception of amylase. In the presence of cerulein, increases in dietary protein concentrations caused progressive increases in pancreatic growth parameters (except amylase), which were maximal at 30% casein concentration of the diet for most parameters. The results confirm that pancreatic growth is stimulated by increasing protein concentration of the diet and indicate that a low protein diet, acting through a deficiency of dietary nitrogen and essential amino acids, limits the pancreatic trophic response to CCK or analogues. These results explain the failure of trypsin inhibitors to stimulate pancreatic growth in rats fed low levels of dietary protein.

Alpha2-adrenoceptor antagonists enhance responses of dorsal horn neurones to formalin induced inflammation.

Intrathecally applied alpha2-adrenoceptor antagonists atipamezole, idazoxan and yohimbine had no significant effect on any neuronal response in normal animals. In contrast, all three antagonists (100 microg) significantly increased the area under the curve of the total response to formalin, especially the second phase. Our results suggest the alpha2-adrenoceptor-mediated noradrenergic inhibitory system in the spinal cord is dormant under normal conditions, but controls both the magnitude and duration of the neuronal responses to subcutaneous injection of formalin.