<Emphasis Type="Italic">Mycobacterium avium</Emphasis> disease in wild red-legged partridges (<Emphasis Type="Italic">Alectoris rufa</Emphasis>)

Three wild red-legged partridges (Alectoris rufa) from intensively managed hunting areas in Spain were received for necropsy. They showed granulomatous lesions in different parts of the body, mainly in liver and spleen. Microscope examination of the granulomas showed central caseous necrosis and large amounts of acid-fast bacilli, surrounded by epitheloid cells, giant cells, and lymphocytes. Attempts to isolate and culture the bacillus in Colestsos medium were unsuccessful, but the polymerase chain reaction technique revealed the presence of microorganisms belonging to the Mycobacterium avium complex in one of the partridges. This is the first report of avian tuberculosis in free-living red-legged partridges.     

Systemic nocardiosis in a hill mynah (Gracula religiosa) a pathological study

A case of systemic nocardiosis in a hill mynah (Gracula religiosa) studied by pathological techniques, is described. Macroscopically, greyish white nodular lesions of 2 to 8 mm in diam. were seen in the lungs, kidneys, proventriculus, mesentery and muscles of the eye ball. Histologically, there was replacement of normal parenchyma in these organs by areas of caseation necrosis or granulomas with epithelioid andLanghan's giant cells. The organism was gram and PAS positive, but not acid fast. No culture was obtained.     

Three-dimensional study of the cytoskeleton in macrophages and multinucleate giant cells by quick-freezing and deep-etching method.

The three-dimensional ultrastructure of multinucleate giant cells in subcutaneous granulomas was compared with those of peritoneal macrophages using a quick-freezing and deep-etching method. Subcutaneous granulomas were induced by implanting plastic coverslips in the dorsal subcutaneous tissue of rats. The quick-freezing and deep-etching replicas were prepared from the cells attached to the coverslips. Dense networks of actin filaments were distributed along all peripheral aspects (beneath the plasma membrane, and on free and coverslip-attached surfaces) of the multinucleate giant cells. On the coverslip-attached surface, numerous clathrin-coated pits and vesicles occurred between the actin filaments. In these cells, intermediate filaments, but not actin filaments, were the predominant cytoskeletal components in perinuclear regions and were attached to the cell nucleus, mitochondria and other vesicular cell organelles. A similar distribution of cytoskeletal components was observed in the mononuclear macrophages of the granulomas and the peritoneal macrophages. These results show that the cytoskeletal organization varies in different regions of the cytoplasm of multinucleate giant cells, while the characteristic cytoskeletal arrangement, resembling that of mononuclear macrophages, is maintained.     

Three-dimensional study of the cytoskeleton in macrophages and multinucleate giant cells by quick-freezing and deep-etching method

The three-dimensional ultrastructure of multinucleate giant cells in subcutaneous granulomas was compared with those of peritoneal macrophages using a quick-freezing and deep-etching method. Subcutaneous granulomas were induced by implanting plastic coverslips in the dorsal subcutaneous tissue of rats. The quick-freezing and deep-etching replicas were prepared from the cells attached to the coverslips. Dense networks of actin filaments were distributed along all peripheral aspects (beneath the plasma membrane, and on free and coverslip-attached surfaces) of the multinucleate giant cells. On the coverslip-attached surface, numerous clathrin-coated pits and vesicles occurred between the actin filaments. In these cells, intermediate filaments, but not actin filaments, were the predominant cytoskeletal components in perinuclear regions and were attached to the cell nucleus, mitochondria and other vesicular cell organelles. A similar distribution of cytoskeletal components was observed in the mononuclear macrophages of the granulomas and the peritoneal macrophages. These results show that the cytoskeletal organization varies in different regions of the cytoplasm of multinucleate giant cells, while the characteristic cytoskeletal arrangement, resembling that of mononuclear macrophages, is maintained.     

Semi-quantitative analysis of soft-tissue reactions in fine needle aspirates from tissue cysticercosis

Fine needle aspiration cytology (FNA) has a well-documented role in the diagnosis of cysticercosis. However, little is discussed about the associated inflammatory response in the host tissues. Aspirates from 182 cases of subcutaneous cysticercosis were semiquantitated for the type and degree of inflammatory response, and the amount and preservation of the parasite. Tissue sections were reviewed where available. In the FNA where no parasite was observed but a confirmatory tissue diagnosis was available, it was found that eosinophils (52%), epithelioid cell granulomas (30%), palisading histiocytes (33%) and giant cells (28%) were seen less frequently than in those where larval fragments were identified in the aspirated material in varying quantities, the response being 88-92% eosinophils, 50-70% palisading histiocytes, 68-80% epithelioid cell granulomas and 46-74% giant cells. Repair cells were maximally seen when readily identifiable larval fragments were seen in the aspirate. Bizarre cells were equally distributed in these aspirates. The tissue response in FNA from subcutaneous cysticercosis can be varied and eosinophils are found to increase with the presence of the degenerating parasite. In soft-tissue aspirates, palisading histiocytes with epithelioid cell granulomas with or without giant cells and an inflammatory exudate with predominantly eosinophils alerts one to search diligently for a parasite.     

Experimental histoplasmosis capsulati in athymic nude mice

Granuloma formation in nude (nu/nu) mice and their heterozygous littermates (nu/+ mice) against Histoplasma capsulatum var. capsulatum infection was studied.A culture of H. capsulatum var. capsulatum, isolated from a granuloma in the nasal cavity of a Japanese patient, was used in this experiment. Sixteen specific-pathogen-free male nu/nu and 32 nu/+ mice were used in this study.The nu/+ mice were divided into two groups. Sixteen nu/+ mice in one group and 16 nu/nu mice were inoculated intraperitoneally with 10⁶ yeast cells of the fungus, those in the other group of nu/+ mice were inoculated intravenously with the same number of the yeast cells. Two mice out of each group were sacrificed 2, 3, 7, 11, 14, 18, 25 and 30 days after inoculation, and each of their organs was examined histopathologically. In addition, pieces of these tissues were cultured on Sabouraud's dextrose agar slants.In the nu/+ mice inoculated intraperitoneally, although the fungus was recovered from the spleen, kidney and lymph nodes during the initial course of the infection, lesions were not detected in their histopathological sections. In the nu/+ mice inoculated intravenously, colonies were recovered from all of the organs examined, other than the brain and thymus, 7 days after inoculation.Histopathologically, a few microfoci consisting chiefly of mononuclear cells with or without yeast cells were found in the liver sections 4 days after inoculation. Seven and 11 days after inoculation the number of lesions had increased. They had large accumulations of mononuclear cells. From day 14 on, almost all of the yeast cells had lost most of their staining affinity or were destroyed in the granuloma. From day 25 on, the granulomatous lesions changed gradually to fibrous tissue.In the nu/nu mice the fungus was readily recovered from the spleen, liver, kidney and lymph nodes. Histopathologically, a few microfoci consisting of mononuclear cells were present in the liver sections 4 days after inoculation. That is to say, during the initial course of infection granulomas were formed. In the liver, from day 7 on, the lesions were large and their number increased. However, there was a definite difference between the nu/nu and nu/+ mice. In the former, the yeast cells were not killed, and they continued to multiply within the granulomas. These granulomas were never transformed into fibrous tissue.     

Brugia malayi,Brugia pahangi, and Brugia patei: Pulmonary pathology in jirds, Meriones unguiculatus

The chronological development of pulmonary lesions due to subperiodic Brugia malayi and related species was studied in the jird, Meriones unguiculatus. Major pathologic changes included (1) granulomas induced by larvae and adults, (2) obstructive endarteritis, and (3) chronic interstitial inflammation with degenerating microfilariae. The majority of pulmonary granulomas were initiated near the time of the final molt, about 30 days postinoculation, followed by involution and formation of residual vascular lesions over the next several months. A minority of granulomas arose about sexually mature adult worms and showed a characteristic sequence of development along the length of these worms. Ultrastructural observations suggested that within granulomas internal structures of the worm underwent an autolytic-like disintegration, while the cuticle remained intact. A material, presumably of parasitic origin, then appeared between the cuticle and adherent epitheloid and giant cells and was subsequently phagocytized by these cells. Obstructive endarteritis appeared to peak at about the time of the final molt, and became largely fibrotic by 125 days postinoculation; electron microscopy of the subintimal infiltrates revealed a variety of cells including inflammatory cells and others interpreted as modfied cells of vascular origin (smooth muscle cells and two types of endothelial cells).Parasitological data suggested that both larvae and adults migrated to the lungs and that mating occurred here, rather than in peripheral sites of development. In terms of development, reproduction and survival, the pulmonary arteries of the male jird offered a suitable alternative for the localization of these primarily lymphatic filariae; our results thus suggest that the pulmonary localization of these worms should not be considered indicative of an aberrant mode of development. The failure of female jirds to develop detectable peripheral microfilaremia was associated with a high rate of infertility among female worms, rather than pulmonary sequestration or destruction of microfilariae.     

Histopathology of Canine Sporotrichosis: A Morphological Study of 86 Cases from Rio de Janeiro (2001–2007)

The present study reports the histopathological findings of 86 skin lesions of dogs with sporotrichosis from Rio de Janeiro. Suppurative granulomatous inflammation was the predominant finding and was observed in 76 (88.37%) cases. Plasma cells surrounding the suppurative granulomas were detected in 68 (89.5%) cases and an inflammatory infiltrate at the periphery of these granulomatous lesions was observed in 63 (82.9%). Fungus-specific staining revealed yeast cells compatible with Sporothrix schenckii in 36 cases. These fungal elements were only detected in lesions characterized by suppurative granulomatous inflammation. Thus, specific staining of serial sections is recommended in the case of dogs with skin lesions whose histopathological presentation is consistent with sporotrichosis. However, due to the generally small number of yeast cells in lesions, the hypothesis of sporotrichosis should not be ruled out even if the result is negative, especially in epidemic areas where correlation with epidemiological data is particularly useful.     

Histological and ultrastructural features of gastrointestinal basidiobolomycosis

Basidiobolus ranarum is a fungus found in the dung of amphibians, reptiles, and insectivorous bats. Its structural elements include both hyphae and zygospores. Patients with B. ranarum infection may present with subcutaneous, gastrointestinal, or systemic lesions. Here we report a case of gastrointesinal badidiomycosis in a 13-year-old male child who presented with acute abdomen. Exploration revealed a mass in the ascending colon. On histology, transmural granulomatous inflammation composed of abundant eosinophils, lymphocytes, histiocytes and giant cells was seen. Histochemical stains revealed broad, non-septate, hyphae-like structures surrounded by an eosinophilic sheath. On an ultrastructural level, fungal hyphae, spores, and macrophage-laden crystalloids were observed. The diagnosis of gastrointestinal basidiobolomycosis was established and the patient received antifungal treatment. This paper reviews the relevant literature regarding basidiomycosis, and discusses its diverse clinicopathological features, as well as distinguishing it from other diseases.     

Experimental infection of white mouse with chrysosporium and paecilomyces

SPF white mice were inoculated intraperitoneally with 5 strains of saprophytic fungi of the mycelial genera Chrysosporium (C. keratinophilum, C. tropicutn) and Paecilomyces (P. lilacinus, P. marquandii, P. victoriae). The fungi caused granulomatous lesions in the peritoneal cavity and they were recultured (except P. lilacinus and P. marquandii) two months after inoculation. Spores, short hyphae and budding cells of all the fungi were observed in the granulomas stained by periodic-acid Schiff (PAS) and methenamine-silver nitrate (Grocott) techniques.     

Experimental reproduction of the Jorge Lobo's disease in BALB/c mice inoculated with Lacazia loboi obtained from a previously infected mouse

Long-term maintenance of Lacazia loboi in the laboratory has not been reported. We report here the use BALB/c mice to maintain the Lacazia loboi for extended period of time. Eight to ten week-old mice were inoculated intradermally in both hind footpads with a fungal suspension from a macerated footpad obtained from an original mouse previously infected with the fungi and sacrificed 8 months after inoculation. The inoculated animals were sacrificed at different time intervals, footpads were excised, the right one was submitted to histopathological examination and the left one was macerated in sterile saline for fungal count and viability index determination. The inoculated animals presented the histopathological picture identical to the mice previously inoculated with material from human lesion. Granulomatous infiltrates with predominance of macrophages and giant cells were observed. The granulomas evolved progressively as observed in the different times of sacrifice. After 7 months of inoculation, macroscopic lesions were observed, and the number of fungi obtained from macerated footpads was higher than the number of inoculated fungi. The pattern of lesion development was similar to what was observed in animals infected with a fungal suspension obtained from a human lesion. Considering the histopathological findings, the clinical manifestations, and the finding of a higher number of fungi obtained than the inoculated into footpads of each mice, we believe the BALB/c mice strain is as an excellent way to maintain L. loboi in laboratory. Moreover, even after serial passages of the fungi, the granulomatous lesions are reproduced consistently in laboratory conditions.This revised version was published online in October 2005 with corrections to the Cover Date.     

Brugia pahangi: Histopathological study of golden hamsters

Sixteen male hamsters were inoculated subcutaneously with 95 to 150 infective larvae of B. pahangi and were examined for histopathologic lesions at 39–109 days postinfection. The basic microscopic lesion observed was obstructive granulomatous lymphangitis. Analogous lymph node changes sometimes occurred along with lymphoreticular hyperplasia and increased numbers of eosinophils. Cellular infiltration of perivascular and perinodal tissues was common, with plasma cells and eosinophils predominating. Genital lesions included funiculitis, epididymitis, and mild orchitis. Live and dead worms were found in the testicular parenchyma. Pulmonary changes in hamsters infected more than 105 days included multiple small, granulomatous foci and periarteriolar, peribronchiolar, and subpleural cellular accumulations of plasma cells and eosinophils. Granulomatous obstruction of pulmonary arteries associated with dead worms was observed in two hamsters infected for 39–45 days and in one hamster infected for 109 days. Small liver granulomas were common. Disintegrating microfilariae occurred within giant cells in the lymph nodes, spleen, lungs, and testes.     

Dendritic Cells in Chronic Mycobacterial Granulomas Restrict Local Anti-Bacterial T Cell Response in a Murine Model

Background

Mycobacterium-induced granulomas are the interface between bacteria and host immune response. During acute infection dendritic cells (DCs) are critical for mycobacterial dissemination and activation of protective T cells. However, their role during chronic infection in the granuloma is poorly understood.

Methodology/Principal Findings

We report that an inflammatory subset of murine DCs are present in granulomas induced by Mycobacteria bovis strain Bacillus Calmette-guerin (BCG), and both their location in granulomas and costimulatory molecule expression changes throughout infection. By flow cytometric analysis, we found that CD11c⁺ cells in chronic granulomas had lower expression of MHCII and co-stimulatory molecules CD40, CD80 and CD86, and higher expression of inhibitory molecules PD-L1 and PD-L2 compared to CD11c⁺ cells from acute granulomas. As a consequence of their phenotype, CD11c⁺ cells from chronic lesions were unable to support the reactivation of newly-recruited, antigen 85B-specific CD4⁺IFNγ⁺ T cells or induce an IFNγ response from naïve T cells in vivo and ex vivo. The mechanism of this inhibition involves the PD-1:PD-L signaling pathway, as ex vivo blockade of PD-L1 and PD-L2 restored the ability of isolated CD11c⁺ cells from chronic lesions to stimulate a protective IFNγ T cell response.

Conclusions/Significance

Our data suggest that DCs in chronic lesions may facilitate latent infection by down-regulating protective T cell responses, ultimately acting as a shield that promotes mycobacterium survival. This DC shield may explain why mycobacteria are adapted for long-term survival in granulomatous lesions.     

Lack of cathepsin activities alter or prevent the development of lung granulomas in a mouse model of sarcoidosis

Background

Remodeling of lung tissues during the process of granuloma formation requires significant restructuring of the extra-cellular matrix and cathepsins K, L and S are among the strongest extra-cellular matrix degrading enzymes. Cathepsin K is highly expressed in various pathological granulomatous infiltrates and all three enzymes in their active form are detected in bronchoalveolar lavage fluids from patients with sarcoidosis. Granulomatous inflammation is driven by T-cell response and cathepsins S and L are actively involved in the regulation of antigen presentation and T-cell selection. Here, we show that the disruption of the activities of cathepsins K, L, or S affects the development of lung granulomas in a mouse model of sarcoidosis.

Methods

Apolipoprotein E-deficient mice lacking cathepsin K or L were fed Paigen diet for 16 weeks and lungs were analyzed and compared with their cathepsin-expressing littermates. The role of cathepsin S in the development of granulomas was evaluated using mice treated for 8 weeks with a potent and selective cathepsin S inhibitor.

Results

When compared to wild-type litters, more cathepsin K-deficient mice had lung granulomas, but individually affected mice developed smaller granulomas that were present in lower numbers. The absence of cathepsin K increased the number of multinucleated giant cells and the collagen content in granulomas. Cathepsin L deficiency resulted in decreased size and number of lung granulomas. Apoe-/- mice treated with a selective cathepsin S inhibitor did not develop lung granulomas and only individual epithelioid cells were observed.

Conclusions

Cathepsin K deficiency affected mostly the occurrence and composition of lung granulomas, whereas cathepsin L deficiency significantly reduced their number and cathepsin S inhibition prevented the formation of granulomas.     

Giant Cells: Contradiction to Two-Hit Model of Tuber Formation?

Tuberous sclerosis (TSC) is an autosomal dominant disease characterized by the formation of hamartomatous lesions in many organs, including brain, heart or kidneys. It has been found that TSC is caused by the mutation in one of the two tumor suppressor genes: TSC1 or TSC2, encoding hamartin and tuberin, respectively. According to Knudson’s two-hit model of tumorigenesis, second-hit mutation and resulting loss of heterozygosity (LOH) of a tumor suppressor gene is necessary for tumor formation. In fact, LOH is commonly found in several types of hamartomas formed in the process of tuberous sclerosis, but, interestingly, not in brain lesions, containing characteristic giant cells. In this paper, we review literature covering origination of giant cells and present several hypotheses explaining why in spite of the presence of hamartin and tuberin, brain lesions form in TSC patients.     

Imaging of luciferase and GFP‐transfected human tumours in nude mice

Studies were performed to compare green ?uorescent protein (GFP)‐transfected and ?re?y luciferase (Luc)‐transfected MCF‐7 human breast tumour cells both in vitro and in vivo. For in vitro studies, cells were serially diluted in 96‐well microplates and analysed using a NightOwl LB 981 Molecular Light Imager and a Victor multilabel reader. For in vivo studies, nude mice were injected either intraperitoneally, intravenously or subcutaneously with transfected cells and then imaged using the NightOwl Imager after intraperitoneal injection of d ‐luciferin for Luc tumours, or excitation at 470 nm for GFP tumours. In vitro imaging studies revealed that both GFP and Luc transfectants were quanti?able. However, the Luc‐transfected cells were detectable at a signi?cantly lower concentration compared to GFP transfectants. In vivo studies demonstrated that GFP‐transfected tumours were detectable as subcutaneous and intraperitoneal tumours but not as deep tissue lesions, whereas Luc‐transfected tumours were detectable as subcutaneous and intraperitoneal tumours and as deep tissue lesions resulting from intraperitoneal or intravenous inoculation. These ?ndings demonstrate that GFP‐transfected cells may be useful for imaging studies of super?cial tumours where both excitation and emission wavelengths are able to penetrate tissues, whereas luciferase‐transfected cells appear superior for imaging studies of primary and metastatic tumours in distant sites and deep tissues. Copyright © 2003 John Wiley & Sons, Ltd.     

Thyroid tuberculosis – role of PCR in diagnosis of a rare entity

N. Gupta, K. Sharma, A. Barwad, M. Sharma, A. Rajwanshi, P. Dutta and A. Sharma
Thyroid tuberculosis – role of PCR in diagnosis of a rare entity Background: Tuberculosis is a rare cause of granulomatous thyroiditis, whose diagnosis may be difficult with routine cytopathology and staining for acid‐fast bacilli (AFB). Study design: Amongst 7962 cases of various thyroid lesions subjected to fine needle aspiration cytology (FNAC) over a period of 12 years, 34 cases (0.43%) were found to have cytological features of granulomatous inflammation with or without necrosis, which could be due to tuberculosis, granulomatous thyroiditis or other causes of granulomatous inflammation such as sarcoidosis or fungal infections. DNA was extracted from the material available on May‐Grünwald–Giemsa‐stained smears from the archival material. PCR for Mycobacterium tuberculosis was performed for insertion sequence IS6110. Results: The age of the patients ranged from 32 to 58 years (median 48 years); 24 were female and 10 male. FNAC from thyroid swellings showed epithelioid granulomas with giant cells and/or necrosis. Although acid‐fast bacilli were only seen in smears in two cases, 19/34 (55.9%) showed the presence of 123 bp DNA band under ultraviolet transillumination. Five control cases were negative. Conclusion: Our study of archival cytological material illustrates the importance of PCR as a potentially useful tool for the detection of M. tuberculosis DNA from FNAC of thyroid lesions, which could provide an alternative for rapid diagnosis of thyroid tuberculosis in AFB‐negative cases.     

The differentiation of monocytes into macrophages,epithelioid cells,and multinucleated giant cells in subcutaneous granulomas

The morphological changes occurring in monocytes during their differentiation into macrophages, epithelioid cells, Langhans-type giant cells, and foreign-body-type giant cells were investigated in foreign-body granulomas induced by subcutaneous implantation of pieces of Melinex plastic. Analysis based on Adams's (1974) criteria for discrimination between the several types of cell of the monocyte line, showed that each type has a characteristic type of granule. Primary and secondary granules, numerous in the Golgi area of monocytes were generally found close to the cell membrane and decreased in number in maturing macrophages. This was accompanied by an increase in the number of microtubules. Mature macrophages show numerous characteristic macrophage granules, which are round (average diameter: 280 nm) and have a halo between the limiting membrane and granular matrix. Mature epithelioid cells have characteristic epithelioid cell granules, and multinucleated giant cells a heterogenous population of granules. Fusing macrophages generally have their Golgi areas facing each other, and also show a reduced thickness of the cell coat. The morphology of the multinucleated giant cell is closely related to the number of nuclei present. In Langhans-type giant cells, which generally have two to ten nuclei, a giant centrosphere with numerous aggregated centrioles is found. In transition forms between Langhans-type and foreign-body-type giant cells, which generally contain 10--30 nuclei, the centrioles show less aggregation. In the foreign-body-type giant cells, which generally have more than 30 nuclei, centrioles are virtually absent and never aggregated. These differences between the Langhans-type giant cells, the foreign-body-type giant cells, and the transition forms, support our previous finding that Langhans-type giant cells are the precursors of foreign-body-type giant cells.     

Electron microscopic cytochemical analysis of hepatic granuloma induced by Cryptococcus neoformans

The hepatic granulomas in experimental cryptococcosis were analyzed by peroxidase (PO) cytochemistry. Cryptococcus neoformans was inoculated intravenously into rats (group A), and some rats were administrated with dextran sulphate to suppress Kupffer cell functions before inoculation (group B). All rats were sacrificed 7 days after inoculation. The livers were examined PO cytochemically. In addition, the liver, spleen, lungs, kidneys and brain were also examined histopathologically. The hepatic granulomas consisted of the following four type cells; exudate macrophages (type I), PO-negative macrophages (type II), Kupffer cells (type III), and other inflammatory cells (type IV) such as neutrophils and lymphocytes. The percentages of the granulomacomposing cells in group A were 10.3% (type I), 27.3% (type II), 52.9% (type III) and 9.5% (type IV), respectively. In contrast in group B, type II cells outnumbered type III cells by a ratio of 53. In group B, necrosis and hemorrhage were observed in the granuloma. The lesions in the lungs changed from granulomatous to cystic ones after suppression of the Kupffer cell functions. These results suggest that resident macrophages such as Kupffer cells may play an important role in the formation of cryptococcal lesions.     

A model of T-cell unresponsiveness using the male-specific antigen, H-Y

Granuloma formation in schistosomiasis japonica differs in several respects from those observed in Schistosoma mansoni infections. We have utilized the lung granuloma model in mice sensitized with subcutaneous injection of Schistosoma japonicum eggs to study the kinetics and mechanisms of this response. Animals injected subcutaneously with a range of 50–50,000 S. japonicum eggs elicited a significant pulmonary granulomatous response around ova subsequently injected intravenously. The pulmonary granulomas were formed of macrophages, lymphocytes, and eosinophils. Both antithymocyte globulin and antieosinophil sera reduced significantly the size of the granulomas and depleted the corresponding cell. Nude athymic mice developed markedly reduced pulmonary granulomas as did mice treated with niridazole or hydrocortisone. Sensitization to the egg antigens was demonstrable as both immediate and arthus-type footpad responses. Our data show that cell-mediated pulmonary granulomas can form around S. japonicum eggs in animals previously sensitized by the subcutaneous route. This model may provide further insights into the pathogenesis of S. japonicum granuloma.