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Background: Although gastric reserve volume (GRV) is a surrogate marker of gastrointestinal dysfunction and feeding intolerance, there is ambiguity in its estimation due to problems associated with its measurement. Introduction of point-of-care ultrasound as a tool for anesthetists kindled interest in its use for GRV estimation., Methods: In this prospective observational study, we recruited 57 critically ill patients and analyzed 586 samples of GRV obtained by both ultrasonography (USG) and manual aspiration., Results: The analysis showed that USG-guided GRV was significantly correlated (r=0.788, P<0.001) and in positive agreement with manual aspiration based on Bland-Altman plot, with a mean difference of 8.50±14.84 (95% confidence interval, 7.389-9.798). The upper and lower limits of agreement were 37.7 and -20.5, respectively, within the ±1.96 standard deviation (P<0.001). The respective sensitivity and positive predictive value, specificity and negative predictive value, and area under the curve of USG for feeding intolerance were 66.67%, 98.15%, and 0.82%, with 96.49% diagnostic accuracy., Conclusions: Ultrasonographic estimation of GRV was positively, significantly correlated and in agreement with the manual aspiration method and estimated feeding intolerance earlier. Routine use of gastric USG could avoid clinical situations where feeding status is unclear and there is high risk of aspiration and could become a standard practice of critical care.

Background: Toxoplasmosis causes serious and sometimes life-threatening disease in immunocompromised patients like organ transplant recipients, immunodeficiency disorders or HIV-infected individuals. The co-occurrence of toxoplasmosis in a respiratory sample harboring tuberculosis (TB) may be missed especially in an area endemic for the latter infection., Case Report: A 10-year-old child presented with complaints of fever with loss of appetite and weight. Based on radiological and clinical features, a presumptive diagnosis of pulmonary TB was made and bronchoalveolar lavage (BAL) performed for cytological and microbiological confirmation. Smears from BAL showed numerous lymphocytes along with few ciliated columnar epithelial cells. Ziehl-Neelsen stain for acid-fast bacilli was positive. The Giemsa-stained cytosmears also showed clusters of crescent-shaped tachyzoites of toxoplasma gondii in a background of lymphocytes. The patient was initiated on anti-tubercular therapy with marked clinical improvement., Conclusion: A diligent screening of cytosmears for a possible coinfection in a TB-positive sample is essential for the cytopathologists to detect coexisting toxoplasmosis, which is a rare but treatable disease., (© 2020 Wiley Periodicals LLC.)

Objective: To compare maternal and perinatal outcomes in pregnant women with underlying heart disease who underwent induction of labor with those who had spontaneous labor., Materials and Methods: A total of 50 pregnant women with heart disease who were registered in cardio-obstetric clinic were recruited consecutively between 38-41 weeks' gestation. Patients with favorable Bishop scores at 38 weeks were randomized into two groups. Induction of labor with oxytocin was performed in one group, and the second group underwent spontaneous onset of labor. Descriptive analysis in terms of mean, standard deviation, and percentage was performed. Unpaired t-test was applied for comparison of two groups using SPPS statistical software., Results: No significant difference in the rate of maternal complications was observed between the two groups. No cardiac complications were reported in pregnant females who underwent induction of labor. Fifty-two percent of patients delivered during workday hours when labor was induced, whereas only 24% of pregnant women delivered during working hours who underwent spontaneous delivery. No maternal or neonatal deaths were reported., Conclusion: Induction of labor with oxytocin is a relatively safe procedure in women with heart disease, it does not result in any cardiac complications. More patients delivered during daytime when electively induced, which minimized the maternal and fetal risks because obstetric, anesthesiologist, cardiologist, and perinatologist specialists are readily available during the daytime., Competing Interests: Conflict of Interest: No conflict of interest was declared by the authors., (©Copyright 2019 by Turkish Society of Obstetrics and Gynecology | Turkish Journal of Obstetrics and Gynecology published by Galenos Publishing House.)

Background: The pathogenesis of myocardial infarction (MI) involves environmental and genetic risk factors, with the latter putatively playing significant roles in younger patients. Genetic variability in coagulation factors comprises one such group. The coagulation factor 13 subunit A (F13A1) Val34Leu polymorphism (rs5985) has yielded variable findings in literature, with no prior South Asian data., Methods: We studied the frequency of this polymorphism using the amplification-created restriction-enzyme site (ACRES) polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 101 MI patients aged below 40 years and 103 controls along with plasma fibrinogen and serum homocysteine levels., Results: The distribution of Val/Val, Val/Leu and Leu/Leu genotypes was similar among cases (72.3%, 26.7% and 1.0%) and controls (78.6%, 19.4% and 1.9%, respectively). Val and Leu allele frequencies were 85.6% and 14.4% among patients and 88.3% and 11.7% among controls, respectively (p = .416). Mean plasma fibrinogen was higher in patients vis-à-vis controls (3.1 versus 3.7 g/l; p < .001) but homocysteine was elevated in both patients (52%) and controls (67%) (p = .225). Multivariate analysis revealed hypertension (p < .001, OR 6.16) and smoking (p < .001, OR 5.48) to impart strongest risk followed by positive family history, plasma fibrinogen levels and male gender., Conclusions: Despite its small sample size, this first South Asian study suggests neither protective nor deleterious effects of the F13A1 Val34Leu polymorphism on the risk of MI in young persons. The Leu allele frequency is intermediate to that reported from the West and the Far East. Traditional risk factors contribute greatly to risk even in younger MI patients in South Asia.

The aim of this study was to evaluate the association of prothrombotic gene polymorphisms [factor V Leiden (FVL) 1691GA, factor VII (FVII) 10976GA, FVII HVR4, platelet membrane glycoproteins GP1BA 1018CT, GP1BA VNTR, integrin ITGB3 1565TC, integrin ITGA2 807CT and methylenetetrahydrofolate reductase (MTHFR) 677C/T], plasma factors (fibrinogen and homocysteine) and traditional risk factors with acute myocardial infarction (AMI) in 184 patients ≤ 40 years of age and 350 controls (≤ 40 years) from north India. Multiple logistic-regression analysis showed that hypertension (OR 1.9, 95 % CI 1.1-3.8, p = 0.042), diabetes mellitus (OR 10.5, 95 % CI 2.0-56.7, p = 0.006), smoking (OR 7.1, 95 % CI 3.7-13.6, p < 0.001), low socio-economic status (OR 13.5, 95 % CI 2.3-78.4, p = 0.004), high waist-hip ratio (OR 35.6, 95 % CI 11.1-53.7, p < 0.001) and FVL 1691GA (OR 6.0, 95 % CI 1.2-13.4, p = 0.03) were independent risk predictors of AMI in young. Elevated plasma fibrinogen also showed association with increased AMI risk. ITGA2 807C/T polymorphism showed protection against AMI in univariate analysis only, while GP1BA VNTR-ac (OR 0.4, 95 % CI 0.2-0.9, p = 0.033) showed significant protection even after adjusting for age and sex. Multinominal logistic-regression analysis showed gene-gene (GP1BA 1018C/T with GP1BA VNTR and ITGA2 807C/T with ITGB3 1565T/C polymorphisms) and gene-environment interactions (gene polymorphisms with smoking) operating in the occurrence of AMI in young. In conclusion, the role of inherited predisposition to thrombosis in complex, polygenic and multifactorial disease like AMI is limited to certain genetic factors, in combination with environmental factor like smoking.

Background: We carried out a study to evaluate the effects of protective premedication with Acetaminophen, Gabapentin and combination of Acetaminophen with Gabapentin on post-operative analgesia in patients undergoing open cholecys-tectomy under general anesthesia. PATIENTS #ENTITYSTARTX00026;, Methods: The study was conducted in a double-blind randomized and controlled manner in 120 consenting patients of either sex belonging to ASA physical status grade I and II, between the age groups of 20 to 50 years, weighing between 40 to 65 kg and undergoing elective surgery (open cholecystectomy) under general anesthesia. The patients were divided into 4 groups: 1: placebo, 2: Acetaminophen 1000 mg, 3: 1200 mg Gabapentin, 4: Acetaminphen 1000 mg plus 1200 mg Gabapentin. The drugs were given two hours before induction. Time, number and total amount of rescue analgesic (tramadol) and VAS score at rest and on movement. Side effects like any episode of nausea/vomiting and level of sedation were noted., Results: Premedication with antihyperalgesic and analgesic agents helps to decrease postoperative pain scores. Gabapentin premedication is effective for providing better postoperative pain relief with lower and delayed requirements of rescue analgesics, but causes more episodes of nausea and vomiting and higher levels of sedation.

Aflatoxin B1 (AFB1) has been classified as a category I human carcinogen, which is responsible for a high incidence of hepatocellular carcinoma. Since exposure to AFB1 can occur through skin contact in addition to ingestion and inhalation, the carcinogenic potential of topically applied AFB1 on mouse skin was investigated. Our results show that single topical application of AFB1 (80 nmol) as a tumor initiator, followed by twice weekly application of 12-tetradecanoyl phorbol myristate acetate (TPA, 4 nmol), resulted in tumor formation after 13 weeks. However, no tumorigenic potential was observed when AFB1 (16 nmol) was used either as a complete carcinogen or as a tumor promoter (4 nmol). Histological analysis of skin showed squamous cell carcinoma in the AFB1/TPA treated group. The application of AFB1 as a complete carcinogen, an initiator or a promoter after 24 weeks demonstrated widespread degenerative and necrotic changes in hepatic tissue as well, suggesting liver to be the target organ following percutaneous absorption. Additionally, twice weekly topical application of AFB1 caused significant induction of cutaneous CYP IA monoxygenases without any effect on hepatic levels while glutathione-S-transferase activity was induced more in the liver than skin. The topical application of AFB1 also resulted in increased hepatic and cutaneous lipid peroxidation with concomitant depletion of glutathione content. It is likely that due to higher induction of hepatic GST activity, products of lipid peroxidation may be detoxified and therefore unable to cause DNA damage making mice resistant to hepatic tumor formation. The overall results indicate a tumor initiating potential of AFB1 in mice and suggest that continued dermal exposure of AFB1, even at low doses, might lead to degenerative changes in hepatocytes.

The potential of Picroliv, a herbal extract against acute cadmium (Cd) intoxication, was evaluated in male rats. Biochemical and histopathological profile in rats pretreated with Picroliv (12 mg/kg, oral) followed by a single dose of Cd as cadmium chloride (CdCl2) (3 mg/kg, ip) revealed marked suppression of oxidative stress in liver and testes. The Cd-induced enhanced levels of lipid peroxidation, membrane fluidity and reduced levels of nonprotein sulphydryls and Na(+)K(+)ATPase were significantly restored to near normal by Picroliv pretreatment. In addition, the Cd-induced serum levels of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, gamma glutamyl transpeptidase and lactate dehydrogenase were restored to near basal levels. Hepatic and testicular histopathological damage was also minimized. The results strongly suggest definite hepato- and testicular protection by Picroliv. The antioxidant potential of the herbal extract in the major part, and not its chelating property, seems to be responsible for its ameliorative action.

The immunotoxicological effects of piperine were investigated in Swiss male mice, gavaged at a dose of 1.12, 2.25 or 4.5 mg/kg body weight for five consecutive days. All the dose levels had no overt toxic effect and the liver gained weight normally. Treatment at highest dose, however, resulted in significant decrease in the weight of spleen, thymus and mesenteric lymph nodes, but not of peripheral lymph nodes. All the dose levels suppressed the cellular population of lymphoid organs, except for the spleen, where the doses of 1.12 and 2.25 caused an increase. Haematologically, doses of 2.25 and 4.5 mg/kg caused a significant reduction in total leucocyte counts and differential leucocyte counts showed an increase in the percentage of neutrophils. The higher doses of 2.25 and 4.5 mg/kg suppressed the mitogenic response of B-lymphocyte to lipopolysaccharide. The number of primary antibody (IgM) forming cells in the spleen and the level of primary antibody in serum, was decreased. The doses of 1.12 and 2.25 mg/kg suppressed the mitogenic response of T-lymphocytes to phytohaemagglutinin and the nitroblue tetrazolium (NBT) dye reducing activity of peritoneal exudate cells (PECs). Since the lowest dose of 1.12 mg of piperine per kg body weight had no immunotoxic effect, it may be considered as immunologically safe "no observed adverse effect level (NOAEL)" dose.

Objective: To investigate the effect of Lead (Pb) acetate exposure on Semliki forest virus (SFV) pathogenesis in mice., Methods: Different doses (62.5, 125, 250 and 500 mg/Kg body weight) of Pb dissolved in normal saline were given to mice by oral intubation in a sub-acute (28 days) and sub-chronic (90 days) regimen followed by SFV infection. Morbidity, mortality, clinical symptoms, mean survival time (MST), changes in body and organ weight, accumulation of lead in soft tissues, virus titre in brain and histopathological alterations were compared between lead exposed and infected groups., Results: Early appearance of virus symptoms, increased mortality, decreased MST, enhanced SFV titre and greater tissue damage were observed in lead exposed-SFV-infected mice., Conclusion: Pre-exposure to lead increases the susceptibility of mice towards SFV infection. Further studies are suggested in view of the persistence of lead in the environment and the possibility of infection by microbial pathogens.

The scum of waste crankcase oil (SWCO) forms due to weathering of waste crankcase oil, deposited on the surface of water bodies. It is known to attach to the feathers of aquatic birds and cause toxicity to the eggs of nestling birds. The water bodies contaminated with SWCO can also be a source of toxicity to the human beings and animals entering such bodies. Since SWCO used in the present study had an appreciable content of heavy metals like Zn, Pb, Cd, Mn, Cr and Ni, the present investigation was undertaken to study a probable effect on immune system of mice. Animals treated with SWCO at a dose of 0.5, 1.0, 2.0, or 4.0 g/kg body weight for 28 days, had no effect on the weight gain of vital organs. A depressing effect was observed on the cell population of spleen and thymus. The number of primary antibody (IgM) producing cells was significantly depressed in spleen. The IgM antibody titer of serum, reduction of NBT dye by peritoneal exudat cells and mounting of delayed hypersensitivity response were not affected. In view of above immunotoxic effects of SWCO, the waste crankcase oil should be carefully disposed of, away from water bodies.

In order to study environmental pollution in and around a petroleum refinery complex, a multielemental instrumental neutron activation analysis (INAA) method was used to assay concentrations of As, Ba, Br, Cl, Co, Cr, Cs, Cu, Fe, Hg, La, Mn, Mo, K, Na, P, Sc, Rb, Se, Sr, W and Zn in the rumen fluid ash samples of buffaloes from the vicinity of the refinery. Corresponding samples from a control area 300 km away from the refinery were analysed. Standard Reference Materials, Bovine liver (SRM 1577a), Oyster tissue (SRM 1566a) and Animal bone (CRM H-5) were also analysed for quality control. Samples were irradiated with thermal neutrons at 10(12)-10(13) n cm-2 s-1 and counted by high-resolution gamma spectrometry. Mean elemental concentrations of As, Ba, Br, Cr, Hg and Fe were found to be enhanced, whereas those of Na, K, Cl, Cu, Mn and P were depleted in samples from the vicinity of the refinery complex compared to controls. The environmental implications of anomalous elemental concentrations are discussed.

An unexpected mortality of more than 300 cattle was investigated near a metal recovery factory located in a rural area of the Thane district of India. The factory was engaged in reclaiming lead, aluminum, tin, and zinc from discarded lead storage batteries and soft drink cans. The environmental samples (soil, leaves, grass, slag, water, and sediment), human blood and hair and animal samples (blood, urine, peritoneal fluid, liver, kidney, cow dung, ribs, and femur), collected for analysis revealed toxic levels of lead, cadmium, and chromium. Clinical examination of factory workers and school children revealed cough, fever, gastric problems, abdominal pain, skin lesions (scabies), and blue line on gums. Histopathological examination of animal tissues revealed chronic pathology with lead inclusion bodies in hepatocytes and renal tubules. Based on environmental, clinical, analytical, and histopathological observations, the mortality has been attributed to toxic levels of metals in the body and the malnourished status of the animals.

Subchronic oral exposure to styrene in rodents (25 or 50 mg/kg/day in mice; 160 or 320 mg/kg/day in rats and guinea pigs, 5 days/week) for 4 weeks resulted in moderate congestion of pancreatic lobules, focal inflammatory reactions around islets (in mice) and altered serum insulin level while blood glucose levels remained unaffected. Increased beta cell degranulation together with characteristic neoformation of islets were predominantly seen in pancreas of guinea pigs.

Pathomorphological and immunological alterations caused by a mixture of styrene and dioctyl phthalate were studied in albino mice following oral administration of 0.02, 0.03, 0.05 x LD50 of the mixture. The chemicals were mixed together proportionate to their respective LD50 values and fed in ground nut oil, 5 d/wk for 4 weeks. Histological examination of spleen revealed considerable depletion of cellular population of lymphoid follicles which corresponded to the dose dependent decrease in splenic mononuclear cell population count. The thymic lobules revealed slight atrophy but accompanied by a significant increase in thymocyte population. Correspondingly few significant histological changes were observed in mesenteric and peripheral lymph nodes. The treatment caused impairment of primary humoral immune response to SRBC (IgM) but there was a significant increase in response of splenocytes to B-cell mitogen LPS. There was a suppression of cutaneous delayed type hypersensitivity and increase in splenic lymphocyte response to T-cell mitogen PHA. Simultaneously, indirect immunity represented by decreased phagocytosis and enhanced metabolic function of reducing NBT by peritoneal exudate cells was observed. The in vitro exposure of vero cells to the mixture caused dose dependent protective effect. The results of present study indicate that subchronic exposure to low doses of mixture of styrene and dioctyl phthalate under certain conditions may modulate some of the immune functions as compared to exposure to either chemicals alone.

Three infection models namely an oncogenic virus Encephalomyocarditis (EMCV), a rodent strain of malaria, Plasmodium berghei, and a rodent hookworm parasite, Nippostrongylus brasiliensis, were used to confirm the in vivo immunotoxic potential of styrene reported in our previous communication. The altered host resistance to these challenge infections was evaluated in rodents pre-treated with 0, 0.02, 0.03 or 0.05 x LD50 dose of styrene (5 days/week) for 4 weeks. Significantly increased mortality in mice was observed at the various tested dose levels of styrene when challenged with EMCV. Similarly the results obtained in the malaria infection model indicated increased blood parasitaemia as well as significantly enhanced mortality in styrene-treated animals. Also the rejection of N. brasiliensis was also found to be significantly impaired in animals treated with a higher dose of styrene. These results indicate that the exposure of rodents to styrene can markedly impair host resistance which may have biological significance.

Pathomorphological and immunological studies were carried out on rodents following oral administration of 0, 0.1, 0.25 and 0.5% (w/w) metanil yellow, mixed in diet, for 30 days. No significant change in hematologic parameters and histologic architecture of liver, kidney, mesenteric lymph node, thymus and urinary bladder was observed except for mild desquamation of intestinal villi and moderate changes in Peyer's patches of small intestine with higher doses. Among immunological parameters, significant enhancement in the primary humoral immune response (anti-SRBC IgM plaque forming cells of spleen) was observed with the lowest dose of metanil yellow while higher doses produced opposing effects. An elevated cutaneous delayed type hypersensitivity (DTH) reaction to SRBC was seen in 0.1% metanil yellow treated animals but higher doses did not influence the reaction. The treatment also caused changes in functional capabilities of macrophages. Although these immune alterations could hardly influence the local immunity of gut, as measured by the capacity of animals to cause rejection of Nippostrongylus brasiliensis parasite, the potential to modulate the immunity in general by metanil yellow however assumes considerable biological significance.

PVC dust, following a single intratracheal instillation (25 mg/rat), was substantially cleared through the lymphatic circulation and progressively accumulated in the tracheobronchial lymph nodes (TBLN) in a time-dependent manner for up to 1 year. The tissue response in TBLN during 60-270 days post-instillation of PVC dust was characterized by progressive increase in total organ fresh weight, dry weight, DNA, RNA and protein contents, concurrent with the proliferation of macrophages and hyperplasia of reticular cells. Active phagocytosis and enhanced hydrolytic activity in TBLN was evident around 270 days post-instillation by the appearance of PVC-laden macrophages near and within the dust foci, and increased activity of acid phosphatase, DNAse, RNAse and beta-glucuronidase. PVC dust caused degeneration of macrophages, and consequent release of hydrolytic enzymes resulted in limited cytotoxicity without inducing reticulination and fibrosis in the TBLN. The histology and clinical biochemistry of liver, kidney, spleen and serum were not altered and there were no detectable PVC particles in these tissues at up to 365 days. It is therefore concluded that lymphatic clearance of intratracheally instilled PVC dust results in its accumulation and mild foreign body reaction in TBLN which is non-fibrogenic at up to 365 days post-instillation.

The role of histamine in modulating the immune response of hamsters infected with Ancylostoma ceylanicum (hookworm) was investigated. Histamine administration (20 mg base/hamster x 6 ip) made the immune hamsters susceptible to challenge infection, and on assay the humoral as well as the cell-mediated responses were found to be suppressed. An adverse effect of histamine was observed on lymphocytes but the macrophage function remained unaltered, since the latter lack histamine receptors. These findings provide definite evidence that histamine suppresses specific immune responses, and that contrary to earlier reports this neurotransmitter does not play a direct role in the 'self-cure' phenomenon.

Instrumental and radiochemical neutron activation analyses (INAA, RNAA) have been used to quantify the different elements present in mica samples derived from Indian mines and a factory, together with USGS standards using high-resolution gamma-ray spectrometry. Both samples revealed the presence of several toxic elements in appreciable quantities. When tested in a rat model system over a period of 360 days after intratracheal injection of mica samples of respirable size (50 mg/animal), the animals which received the factory sample containing shellac exhibited enhanced dust-induced pulmonary reaction together with characteristic abscess formation at later periods. The significance of these findings is discussed.

Samples of dust extracted from the lungs and lymph nodes of certain domestic animals from West Bengal, Orissa, Bihar provinces of India were quantitatively analysed using photon excited energy dispersive X-ray fluorescence technique. Thin specimens were prepared for analysis to minimize matrix enhancement and absorption effects. Amongst the various elements analysed, Hg, Fe, Cu, Zn and Pb were found to be present in appreciable amounts. An important finding was the presence of a very high concentration of Hg in extracted dust samples from West Bengal. The significance of the various results obtained in this investigation is discussed.

Pulmonary fibrogenic response was investigated in mice following intratracheal inoculation of amosite, anthophylite and tremolite varieties of Indian asbestos and studies were made over a period of 150 days. At early periods all the varieties produced acute inflammatory reaction in the lungs. Thick reticulum fibers were encountered at later periods with amosite, while only thin reticulum fibers developed with anthophyllite or tremolite variety. The formation of asbestos bodies did not take place with any of the asbestos varieties even at 150 days. The deviation in the pulmonary fibrogenic response in mice has been attributed to species difference.

Experimental manganese lymphadenopathy was produced by guinea pigs by intratracheal inoculation of manganese dioxide (50 mg/300 g body weight) and histopathologic changes in the tracheobronchial lymph nodes were studied up to 180 days. There was slow extracellular transport of manganese dust into the nodes, which did not provoke any significant reaction at early periods. However, at later periods the nodes exhibited a significant increase in the density of dust particles and the reaction consisted of phagocytosis, degeneration of dust laden macrophages, slight proliferation of fibroblasts, together with some reticulinosis corresponding to deposits of dust particles. The significance of these findings have been discussed from the chronic toxicity viewpoint.

Male mice given different oral doses (0.05, 0.03 or 0.02 x LD50/animal/day) of styrene (LD50 = 1 g/kg) daily for 5 days did not incite any overt toxicity in lymphoid organs or on hematologic parameters. At the tested dose levels styrene produced a mild reduction in the organ weight of adrenal and spleen and slight reduction in the cellular viability of lymph nodes. There was a dose-dependent suppression in the humoral immune response (IgM-producing PFCs of spleen and serum anti-SRBC HA titre) to SRBC. The proliferative response to the B-cell mitogen, LPS however revealed a significant increase in the incorporation of 3HT with middle and lowest doses of styrene. The results of cell-mediated immunity appeared somewhat unexpected and more complex as exposure resulted in a dose-dependent enhancement in the cutaneous DTH reaction to SRBC together with increased blastogenic response of splenic lymphocytes to phytohaemagglutinin (PHA). Additionally, there was significant impairment in the functional activity (NBT reduction, attachment and phagocytic indices) of nonadherent and adherent peritoneal exudate cells. Based on the present data the study identifies the immunotoxic potential of styrene and which acts differently on various arms of the rodent's immune system.

Intratracheal inoculations of quartz dust (250 mg/kg body weight) of a particle size less than 5 mum were given in mice and pulmonary tissue reactions studied over a period of 210 days. Acute inflammatory reaction in the lung parenchyma was observed at early periods and later the aggregates of dust laden macrophages encountered around bronchi and blood vessels. Towards the termination of the experiment at 210 days the fibrotic reaction comprised chiefly of thick compactly arranged reticulin fibers with few collagen fibers which remained restricted to the peribronchial and perivascular areas. There was no silicotic nodule formation in the parenchyma of the lung. The atypical pulmonary tissue response to quartz dust in mice has been attributed to different tissue reactivity.

Histopathological changes in the tracheo-bronchial lymph nodes were studied up to 365 days in guinea pigs following intratracheal injection of a suspension of mica dust. In general, the cytotoxic effect provoked by dust was not pronounced as the majority of the swollen dust-laden macrophages retained their normal structure at the termination of the experiment and fibrotic lesions were limited to the formation of thick reticulin fibers. The poor fibrogenic response of mica dust has been attributed to its low cytotoxicity.

The pathological lesions of bagassosis have been reproduced in guinea pigs given bagasse fibers along with low doses of actinomycete spores. In the early stages, interstitial infiltration with lymphocytes and macrophages as seen in humans was noted. Later, small interstitial bagasse granulomas composed of foreign body giant cells, fibroblasts, and lymphocytes developed, some of which had a laminated appearance. Lymph node changes consistent with an immunological reaction were observed. Actinomycetes alone showed occasional areas of pneumonitis and bagasse alone small granulomas consisting of foreign body giant cells and bagasse fibers. Finally, the combined effect of dust and actinomycetes produced interstitial fibrosis composed of thick reticulin fibers and occasional collagen fibers, which persisted to the end of the experiment. Bagasse alone and actinomycetes alone produced only thin reticulin fibers. It has been suggested that bagassosis is due to the synergistic action of bagasse fibers and Micropolyspora faeni and that in the pathogenesis of the syndrome an immunological component may be involved.

Effect of chrysotile dust alone or together with Candida albicans administered intratracheally in guinea pigs was studied in the genesis of pleural plaques over a period of 12 months. A significant increase of mucopolysaccharides, phosphorus, calcium and -SH content was detected in pleural fluid of animals treated with chrysotile and Candida albicans together than in those treated with chrysotile or Candida albicans alone. The results suggest that an infection of Candida albicans accentuates the effect of chrysotile by altering the biochemical parameters preceding to the formation of pleural plaques.

The pulmonary angiothrombotic lesions in narcotic addicts attributed to the talc present in drug tablets were studied experimentally in guinea pigs following repeated intravenous administration of a suspension of talc dust (75 mg per animal). In early periods there was a moderate localization of talc particles in the alveolar capillaries of lung, liver and abdominal lymph nodes. The vascular injury in the pulmonary tissue was in the form of mild proliferation of the endothelial cells. In addition, many nodular collections comprising macrophages and lymphocytes developed around such vascular structures. At later periods (150 days) the only significant reaction obtained was moderate thickening of interalveolar septa and the lesions were in no way comparable to the human reports. The significance of these findings has been discussed.