Impression cytology on conjunctiva and cornea in dry eye patients establishes a correlation between squamous metaplasia and dry eye clinical severity

PURPOSE

To obtain deeper knowledge of the cellular transition in squamous metaplasia, and to look for a correlation between the clinical grade of severity of dry eye and the grade of squamous metaplasia of the corneal and conjunctival epithelium, studied by impression cytology.

METHODS

A total of 143 patients with dry eye disorders of different grades of clinical severity and 33 control subjects of matched age and sex were studied. Symptoms, clinical tests (including Schirmer test, slit-lamp examination, break-up time, rose Bengal staining, vanishing lacunar sulci, and neovascularization), and tear osmolarity were used to establish the diagnosis of dry eye. The subjects were classified into six clinical grades, grade 0 indicating normal and grades 1 to 5 progressively more severe dry eye. Impression cytology specimens were taken from the central cornea and different areas of the conjunctiva of one eye from all patients. A morphologic and morphometric study of the photographs obtained by light microscopy showed cell size, nuclear size, nuclear-cytoplasmic ratio (N:C) in nonsecretory epithelial cells, and density of goblet cells.

RESULTS

Morphometric and morphologic studies of the ocular surface cells indicated significant differences, mainly in cell sizes, nuclear alterations, and the N:C ratio, in nonsecretory epithelial cells of the conjunctiva and cornea, and in goblet cell densities from the conjunctiva, between the clinically normal eyes and those with the five grades of clinical severity of dry eye, with different degrees of squamous metaplasia.

CONCLUSIONS

A morphologic and morphometric analysis of the ocular surface from patients with dry eye obtained by impression cytology led us to draft a new grading system containing one normal level and five levels of squamous metaplasia. This new grading system is based on a significant decrease in the number of goblet cells with less periodic acid-Schiff-hematoxylin-positive staining, an increase in nonsecretory cell size, more marked cell separation, a lower N:C ratio, and an increase in nuclear alterations. The clinical severity of the dry eye correlates with these alterations.

[Innervation of the lachrymal gland in patients with primary Sjögren's syndrome. An immunohistopathological study]

PURPOSE

Histopathological parameters of the main lachrymal gland from patients with primary Sjögren's syndrome (SS1) were investigated, and the relation between morphological and immunohistochemical changes in the innervation of lachrymal gland in patients with SS1, as well as the immunopathological differences between SS1, non-autoimmune keratoconjunctivitis sicca (KCS) and controls were analysed.

METHODS

Lachrymal glands from patients with SS1, KCS and control subjects were biopsied and examined using standard transmission electron microscopic techniques and an immunohistochemical method (vasoactive intestinal polypeptide-VIP).

RESULTS

Moderate numbers of myelinated and non-myelinated nerve fibres were found in the connective tissue around lachrymal glands in patients with SS1. Non-myelinated nerve fibres made contact with glandular epithelium, myoepithelial cells, vascular endothelium, plasma cells and fibroblasts. Patients with non-immunological KCS had similar characteristics as SS1 in number and activity, showing a normal morphological pattern. Control subjects showed a higher number of active nerve fibres.

CONCLUSION

Main lachrymal gland from patients with SS1 were therefore definitively innervated with moderate activity and normal structures. The ultrastructural study demonstrated there were no statistical differences with respect to patients with non-autoimmune KCS. Immunohistochemical studies showed a similar VIP activity in lachrymal gland between patients with SS1 and KCS, but there was a significant decrease in the innervation activity with regard to control subjects. All this implies that the autoimmunological factor in patients with SS1 does not significantly affect the lachrymal gland innervation.

[Impression cytology contribution to differential diagnosis of Sjögren syndrome in the ophthalmological clinic]

PURPOSE

First, to assess the use of impression cytology, clinical and laboratory tests in the daily clinic for the early diagnosis of Primary Sjögren Syndrome (SS1), and second, to establish morphological differences between SS1, keratoconjunctivitis sicca (KCS) and healthy controls using impression cytology.

MATERIAL AND METHOD

The study comprised 35 patients suffering from primary Sjögren syndrome, same number of patients with keratoconjunctivitis sicca and normal healthy subjects. All groups underwent clinical tests (Schirmer's test, break-up time, and bengal rose staining), laboratory tests (tear protein pattern, tear osmolarity and serum immunoglobulin readings), and impression cytology on different areas of the conjunctiva and cornea.

RESULTS

All patients presented one or more subjective symptoms of ocular irritation although seeming normal at naked eye. Two patients with Sjögren's syndrome showed total corneal keratinization. Clinical and laboratory tests did not show significant differences between Sjögren's syndrome patients group and keratoconjunctivitis group. Serum tests of antibodies and immunoglobulins did present diagnostic values. Impression cytology showed significant differences between Sjögren syndrome patients compared to the rest of groups with regard to epithelial and goblet cells.

CONCLUSIONS

Impression cytology consists in a hystopathological test and it is considered the only ophtalmological test that offers a differential diagnosis in Sjögren's syndrome and should be included in a classification criteria. Inpression cytology presents significant differences between Sjögren syndrome and keratoconjunctivitis sicca.

N-terminal fatty acid substitution increases the leishmanicidal activity of CA(1-7)M(2-9), a cecropin-melittin hybrid peptide

In order to improve the leishmanicidal activity of the synthetic cecropin A-melittin hybrid peptide CA(1-7)M(2-9) (KWKLFKKIGAVLKVL-NH(2)), a systematic study of its acylation with saturated linear fatty acids was carried out. Acylation of the N(epsilon)-7 lysine residue led to a drastic decrease in leishmanicidal activity, whereas acylation at lysine 1, in either the alpha or the epsilon NH(2) group, increased up to 3 times the activity of the peptide against promastigotes and increased up to 15 times the activity of the peptide against amastigotes. Leishmanicidal activity increased with the length of the fatty acid chain, reaching a maximum for the lauroyl analogue (12 carbons). According to the fast kinetics, dissipation of membrane potential, and parasite membrane permeability to the nucleic acid binding probe SYTOX green, the lethal mechanism was directly related to plasma membrane permeabilization.

[Comparison of 2 lacrimal punctal occlusion methods]

PURPOSE

To study and compare two methods for canalicular occlusion: Cautery and Punctal Patch.

METHOD

The study included fourty patients divided in two groups of 20 patients. The end point was 4 occluded puncti. The first group underwent deep cauterization resulting in occlusion of the full vertical aspect of the canaliculus. The second group underwent punctal patch technique for canalicular occlusion. Differential parameters were the following: time of intervention, ease of use, risks and precision. In the post operatory, discomfort, subjective and objective improvement in ocular surface as well as long term result of each technique was analysed.

RESULTS

Time of intervention was longer for punctal patch compared to cautery. Both methods exhibited similar ease of use and improvement in ocular surface. Precision was high in punctal patch technique showing complete and final occlusion and no punctum needed reopening, while cautery technique presented 20% rate of reopening intervention. Postoperatory discomfort and irritation were remarkably evident with punctal technique, while minimal in cautery technique.

CONCLUSION

Survival analysis after one year follow up, showed a higher rate of advantages for punctal patch technique over cautery technique.

[Histopathological and immunohistochemical study of the ocular cicatricial pemphigoid]

OBJECTIVE

To study the relationship between the histopathological alterations and the clinical severity grade in the first phases of the ocular cicatricial pemphigoid to facilitate early diagnosis of the disease and initiate treatment as early as possible.

MATERIAL AND METHODS

We have studied 10 patients with different clinical grades of severity (3 patients with grade I; 4 patients with grade II; 2 patients with grade III, and 1 patient with grade IV). For these patients, full ophthalmologic examinations were performed [clinical, laboratory tests, impression cytology, ultrastructural study, study of direct (IFd) and indirect immunofluorescence (IFi).

RESULTS

The different techniques used have enabled us to observe the diminution of goblet cells, the initiation of subepithelial bullae, separation of epithelial basement membrane, increase and disorganization of collagen fibers, increase in the number of desmosomes, decrease in the number of hemidesmosones, increase in the intraepithelial fibrillar materials and the presence of immunoglobulin deposits and complement in the basement membrane of these patients in the early phases of the disease.

CONCLUSION

The techniques used in this study have enabled us to make an earlier diagnosis of the disease, since it manifests the eye dryness immediately and the posterior biopsy can confirm the differential diagnosis.

Measuring the lacunar sulci as a new indicator of shrinkage of the ocular surface

PURPOSE

To present a new indicator that measures the sulci of the lacrimal lake of the eye according to the degrees of ocular abduction at which they vanish. This new approach will help determine the severity and progression of mucosal retraction in ocular surface diseases.

METHODS

A total of 181 eyes of 94 healthy persons, 130 eyes of 65 patients with Sjogren's syndrome, and 30 eyes of 15 patients with ocular pemphigoid were examined using the slit lamp. We recorded the vanishing point of the three main lacunar sulci (plico-bulbar, plicocaruncular and dermo-caruncular) while abducting.

RESULTS

In healthy persons, the average vanishing points for the first and second lacunar sulci were respectively, 53.20 +/- 12.3 and 54.50 +/- 9.8. In patients with Sjogren's syndrome, 49.53 degrees +/- 10.81 and 53.17 degrees +/- 7.28 and in patients with incipient ocular cicatricial pemphigoid, 42.69 degrees +/- 14.33 and 44.46 degrees +/- 16.85. Statistical significance was p < 0.005.

CONCLUSIONS

The lacunar sulci are shallower and vanish sooner in ocular cicatricial pemphigoid and Sjogren syndrome than in normals. Investigating the vanishing point of the lacunar sulci while abducting is useful for grading the shrinkage of the conjunctiva, caruncle and medial canthus.

In vitro activity of CA(1-8)M(1-18), a synthetic cecropin A-melittin hybrid peptide, against multiresistant Acinetobacter baumannii strains

The in vitro antibiotic activity of CA(1-8)M(1-18), a synthetic cecropin A-melittin hybrid peptide, was determined by broth microdilution on 20 clinical Acinetobacter baumannii isolates with different resistance profiles. The MIC(50), MIC(90) and ranges were 4 mg/l, 4 mg/l and 2-8 mg/l, respectively, and were independent of resistance pattern. Different assay parameters such as microplate plastic (polystyrene or polypropylene), addition of supplements (5-10% fetal calf serum or 5% horse blood), inoculum size (10(5), 10(6), 10(7) and 10(8) CFU/ml) or incubation period (24 or 48 h) were studied. MIC was independent of the first two parameters, although the MIC values increased both with inoculum size or incubation period. Killing curves were obtained both for a standard strain and a multiresistant isolate over a 45.7-2.8 mg/l (16-1 mM) peptide range, using an initial inoculum of 10(5)-10(6) CFU/ml and 10(9)-10(10) CFU/ml. A concentration of 45.7 mg/l was required for complete killing. Accordingly, CA(1-8)M(1-18) showed good in vitro activity against the A. baumannii strains tested irrespective of the resistance to classical antibiotics, and could be a future candidate for multiresistant A. baumannii infections, although further cytotoxicity and pharmacological studies will be needed.

Intrinsic structural differences in the N-terminal segment of pulmonary surfactant protein SP-C from different species

Predictive studies suggest that the known sequences of the N-terminal segment of surfactant protein SP-C from animal species have an intrinsic tendency to form beta-turns, but there are important differences on the probable location of these motifs in different SP-C species. Our hypothesis is that intrinsic structural determinants of the sequence of the N-terminal region of SP-C could define conformation, acylation and perhaps surface properties of the mature protein. To test this hypothesis we have synthesized peptides corresponding to the 13-residue N-terminal sequence of porcine and canine SP-C, and studied their structural behaviour in solution and in phospholipid bilayers and monolayers. In these peptides, leucine at position 1 of both sequences has been replaced by tryptophan in order to allow their study by fluorescence spectroscopy. Far-u.v. circular dichroism spectra of the peptides in aqueous and organic solutions and in phospholipid micelles or vesicles are consistent with predicted conformational differences between the porcine and the canine sequences. Both families of peptides showed changes in their fluorescence emission spectra in the presence of phospholipids that were consistent with spontaneous lipid/peptide interactions. Both canine and porcine peptides were able to form monolayers at air-liquid interfaces, the canine peptides occupying lower area/molecule and being compressible to higher pressures than the porcine sequences. The peptides also shifted the isotherms and perturbed the packing of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) monolayers, the effects being always higher in anionic than in zwitterionic lipids, and also substantially higher in films containing canine peptide in comparison to porcine peptide. Acylation of cysteines at the N-terminal end of SP-C may modulate these intrinsic conformational features and the changes induced could be important for the development of its surface activity.

In vivo monitoring of intracellular ATP levels in Leishmania donovani promastigotes as a rapid method to screen drugs targeting bioenergetic metabolism

A method for the rapid screening of drugs targeting the bioenergetic metabolism of Leishmania spp. was developed. The system is based on the monitoring of changes in the intracellular ATP levels of Leishmania donovani promastigotes that occur in vivo, as assessed by the luminescence produced by parasites transfected with a cytoplasmic form of Phothinus pyralis luciferase and incubated with free-membrane permeable D-luciferin analogue D-luciferin-[1-(4,5-dimethoxy-2-nitrophenyl) ethyl ester]. A significant correlation was obtained between the rapid inhibition of luminescence with parasite proliferation and the dissipation of changes in mitochondrial membrane potential (DeltaPsi(m)) produced by buparvaquone or plumbagin, two leishmanicidal inhibitors of oxidative phosphorylation. To further validate this test, a screen of 14 standard leishmanicidal drugs, using a 50 microM cutoff, was carried out. Despite its semiquantitative properties and restriction to the promastigote stage, this test compares favorably with other bioenergetic parameters with respect to time and cell number requirements for the screening of drugs that affect mitochondrial activity.

Interaction of antimalarial drug quinacrine with nucleic acids of variable sequence studied by spectroscopic methods

The interaction of antimalarial drug quinacrine (QA) with polynucleotides is studied by UV-visible absorption, fluorescence and surface-enhanced Raman spectroscopy (SERS). The polynucleotides employed for such a study were calf thymus DNA, poly(A).poly(T), poly(A).poly(U), poly(C).poly(G) and poly(dG-dC).poly(dG-dC). Absorption and fluorescence spectra of QA complexes indicate that an interaction with the biomolecule is taking place, although different interaction mechanisms are probable depending on the sequence. The SERS spectra also reflect spectral changes which depend on the polymer sequence and that can be correlated to those observed by fluorescence, with the advantage of the detailed structural information provided by this vibrational technique. QA interacts with polynucleotides through its diprotonated form and by ring stacking. The strength of such interaction is extremely sequence dependent, thus suggesting different interaction mechanisms in each case. The SERS technique allows the simultaneous study of those polynucleotide moieties that are directly involved in the interaction thanks to the short-range character of the SERS spectroscopy. The interaction of QA with the above nucleic acids lead to a different change in the chain stability and flexibility which is further related to the different denaturation tendency of the polymer in the presence of the metal surface.

Animal antimicrobial peptides: an overview

Antibiotic peptides are a key component of the innate immune systems of most multicellular organisms. Despite broad divergences in sequence and taxonomy, most antibiotic peptides share a common mechanism of action, i.e., membrane permeabilization of the pathogen. This review provides a general introduction to the subject, with emphasis on aspects such as structural types, post-translational modifications, mode of action or mechanisms of resistance. Some of these questions are treated in depth in other reviews in this issue. The review also discusses the role of antimicrobial peptides in nature, including several pathological conditions, as well as recent accounts of their application at the preclinical level.

Spatial and temporal variability of ground-level ozone in Castilla-León (Spain)

Ozone is a secondary air pollutant that has received extensive attention in the literature, mainly because of the adverse effects that exposure to it can cause, particularly in vegetation during the growing season. Because meteorological conditions strongly influence the efficiency of photochemical processes leading to ozone formation and destruction, ground-level ozone air pollution is currently being considered as a regional-scale phenomenon rather than a local one. This role of O3 as a regional-scale pollutant often implies the handling of large data sets in order to obtain information about its spatial and temporal variability patterns over a given broad region. Rotated principal component analysis (RPCA) is known to be one of the most powerful mathematical tools that can be used to achieve this aim. RPCA was applied in this paper to the summer and winter hourly time series of ground-level O3, concentrations recorded during 2 consecutive years (1996-1997) at 26 urban and suburban sites in Castilla-León (Spain). This procedure permitted the identification of different subregions where O3 concentrations show different spatio-temporal variability patterns. These variability patterns are mainly associated with the interaction of regional-level meteorological and anthropogenic factors. Some differences between winter and summer patterns were also found.

Amyloid precursor proteins in the cerebellar cortex of Alzheimer's disease patients devoid of cerebellar beta-amyloid deposits: immunocytochemical study of five cases

Five human brains affected by Alzheimer's disease (AD), but without cerebellar amyloid (A beta) deposits, were investigated for the presence and location of amyloid precursor proteins (APP). This was parallel to 6 AD brains with A beta deposits, 6 young controls and 6 age-matched controls. Antibodies against A beta and two epitopes of APP (amino and carboxy terminals, APP(60-100) and APP(643-695), respectively) were employed. Accumulations of APP in neurons (mainly Purkinje cells) and glial cells in the upper part of the molecular layer were far greater than those in age-matched control brains and similar to those in AD brains with A beta deposits. This suggests that changes in APP production and/or metabolism occur before A beta deposition, or that these changes can occur without amyloidogenic processing. More than 60% of positive Purkinje neurons were of normal appearance; most of them showed both APP(60-100) and APP(643-695) immunoreactivity, but a small number (<21%) reacted with only a single antiserum. A small number of Golgi, Lugaro and granule cells were APP immunopositive. In all cases, stellate and basket cells were negative, as were most glial cells other than those of the molecular layer. Folia showed two different appearances, which were particularly well displayed in three cases: "strongly" immunopositive folia with high reactivity in Purkinje cells and other neurons, and "weakly" immunopositive folia with low neuronal reactivity, but with a large number of positive glial cells in the molecular layer. The results are discussed in relation to the possible existence of types or stages of the AD process and local factors, including specific and non-specific cell factors, in the induction of APP accumulation. All these 5 cases were female, but the Apo-E 4 genotype was displayed only in two cases.

Protein tyrosine kinase activity in T lymphocytes from patients with systemic lupus erythematosus

We have recently observed an abnormal pattern of protein tyrosine phosphoryl-ation in resting T lymphocytes obtained from peripheral blood of patients with systemic lupus erythematosus (SLE). To examine whether these findings may be related to dysregulated protein tyrosine kinase (PTK) function, we tested the relative amount and enzyme activity of the main PTKs involved in the earliest signalling steps triggered via the CD3 pathway. Cell lysates from peripheral blood T cells in SLE patients showed lower amounts of p59(fyn) and p56(lck) as shown by immunoblot. In contrast, the amount of ZAP-70, a PTK of the syk family, was comparable in both groups. However, p59(fyn) immuno-precipitates obtained from unstimulated peripheral blood SLE T cells showed enhanced PTK activity as compared to controls, whereas the PTK activity of p56(lck) and ZAP-70 molecules was comparable in both groups. The unchecked activity of the TCR/CD3-associated src kinase p59(fyn) may alter the balance needed for regulated T cell responses in SLE patients.

Leishmania pifanoi amastigote antigen P-4: epitopes involved in T-cell responsiveness in human cutaneous leishmaniasis

In experimental murine cutaneous leishmaniasis, the purified Leishmania pifanoi amastigote protein P-4 has been shown to induce significant protection against infection. Further, recent studies examining the response of peripheral blood mononuclear cells (PBMC) from Leishmania braziliensis-infected human patients have demonstrated that the P-4 protein selectively elicits a significant TH1-like response. Because a TH1-like response is associated with cure, epitope studies were conducted to further evaluate the human response to P-4. PBMC from confirmed cutaneous leishmaniasis patients infected with L. braziliensis in Rio de Janeiro, Brazil, an area where the disease is endemic, were examined for T-cell proliferation and/or cytokine production in response to whole-parasite homogenate, isolated P-4 protein, and/or P-4 peptides. Twenty of the 22 patients (91%) examined responded to the native P-4 protein by proliferation and/or gamma interferon (IFN-gamma) production. According to the proliferation data, PBMC from 14 patients (64%) were found to respond to the intact P-4 protein (stimulation index of >/=2.5). Fifty-seven percent of the P-4-responsive patients studied responded to at least one of the P-4 peptides; 11 individual peptides were found to elicit a proliferative response. Of 17 patients examined for cytokine production, no PBMC produced detectable interleukin-4 in response to P-4 protein or peptides. However, PBMC from 14 patients (82%) produced significant levels of IFN-gamma (>/=20 pg/ml) in response to native P-4 protein. Nineteen of the 23 peptides were found to elicit an IFN-gamma response from at least two patients. These data indicate that multiple epitopes spanning the entire P-4 molecule are responsible for the TH1-like immune response observed, indicating that the intact P-4 amastigote molecule, rather than selected peptides, may prove to be the most useful for leishmaniasis vaccine development.

Expression and regulation of mitochondrial uncoupling protein 1 from brown adipose tissue in Leishmania major promastigotes

Rat uncoupling protein 1 (UCP1) was successfully translated in transfected Leishmania major promastigotes. Immune electron microscopy revealed that the protein was exclusively in the mitochondria. UCP1 expression was about 350,000 copies per promastigote, accounting for 4.7% of the total mitochondrial protein. In intact parasites, expression of UCP1 induced a slight increase in respiratory rate and a modest decrease in mitochondrial membrane potential (delta psi(m)). In contrast, in digitonin-permeabilized parasites, a significantly lower value both in delta psi(m) (57 +/- 10 vs 153 +/- 12 mV) and respiratory control ratio (0.99 vs 1.54) were observed for UCP1 versus control parasites, although when UCP1 activity was inhibited by bovine serum albumin (BSA) and GDP, control values were restored. Therefore, a fully functional UCP1 was present and only partially inhibited in vivo by endogenous purine nucleotides. However, neither ATP levels, growth rate nor mitochondrial protein import differed significantly between both types of parasites. Expression of the pore-like mutant UCP1 delta 9 was deleterious to the organism. Consequently, Leishmania was capable of expressing and importing into mitochondria proteins from higher eukaryotes lacking an N-terminal targeting pre-sequence as UCP1. As described previously, parasite metabolism had only a limited tolerance to mitochondrial disfunction. Transfection of Leishmania with foreign proteins which play an important regulatory role in metabolism is a useful tool to study both parasite metabolism in general, and alternative pathways involved in maintaining internal homeostasis.

The plasma membrane of Leishmania donovani promastigotes is the main target for CA(1-8)M(1-18), a synthetic cecropin A-melittin hybrid peptide

Reports on the lethal activity of animal antibiotic peptides have largely focused on bacterial rather than eukaryotic targets. In these, involvement of internal organelles as well as mechanisms different from those of prokaryotic cells have been described. CA(1-8)M(1-18) is a synthetic cecropin A-melittin hybrid peptide with leishmanicidal activity. Using Leishmania donovani promastigotes as a model system we have studied the mechanism of action of CA(1-8)M(1-18), its two parental peptides and two analogues. At micromolar concentration CA(1-8)M(1-18) induces a fast permeability to H+/OH-, collapse of membrane potential and morphological damage to the plasma membrane. Effects on other organelles are related to the loss of internal homeostasis of the parasite rather than to a direct effect of the peptide. Despite the fast kinetics of the process, the parasite is able to deactivate in part the effect of the peptide, as shown by the higher activity of the d-enantiomer of CA(1-8)M(1-18). Electrostatic interaction between the peptide and the promastigote membrane, the first event in the lethal sequence, is inhibited by polyanionic polysaccharides, including its own lipophosphoglycan. Thus, in common with bacteria, the action of CA(1-8)M(1-18) on Leishmania promastigotes has the same plasma membrane as target, but is unique in that different peptides show patterns of activity that resemble those observed on eukaryotic cells.

Macrophage triggering with cecropin A and melittin-derived peptides induces type II nitric oxide synthase expression

Triggering of RAW 264.7 cells with a cecropin A-melittin hybrid peptide (CA(1-8)M(1-18)) promoted a rapid rise in the intracellular calcium concentration that was followed, after a lag period of 6 h, by nitric oxide synthesis through the expression of the cytokine-inducible form of nitric oxide synthase (type II NOS or iNOS). The maximal effect was obtained at peptide concentrations in the 2 to 5-microM range. Simultaneous incubation with the peptide and LPS abrogated the nitric oxide synthesis elicited after LPS treatment of the cells. CA(1-8)M(1-18) induced a rapid activation of nuclear factor kappaB as evidenced by the presence of p50/p65 heterodimers of the nuclear factor kappaB/c-Rel family in the nuclei of activated cells. This peptide also activated the reporter activity of cells transfected with a plasmid harboring a 1-kb fragment corresponding to the 5'-flanking region of the murine iNOS gene. CA(1-8)M(1-18) promoted apoptotic cell death at concentrations below 1 to 2 microM, whereas higher concentrations altered the plasma membrane integrity. These results suggest the involvement of multiple intracellular signaling pathways in the mechanism by which this peptide elicits macrophage triggering.

Macrophage triggering with cecropin A and melittin-derived peptides induces type II nitric oxide synthase expression

Triggering of RAW 264.7 cells with a cecropin A-melittin hybrid peptide (CA(1-8)M(1-18)) promoted a rapid rise in the intracellular calcium concentration that was followed, after a lag period of 6 h, by nitric oxide synthesis through the expression of the cytokine-inducible form of nitric oxide synthase (type II NOS or iNOS). The maximal effect was obtained at peptide concentrations in the 2 to 5-microM range. Simultaneous incubation with the peptide and LPS abrogated the nitric oxide synthesis elicited after LPS treatment of the cells. CA(1-8)M(1-18) induced a rapid activation of nuclear factor kappaB as evidenced by the presence of p50/p65 heterodimers of the nuclear factor kappaB/c-Rel family in the nuclei of activated cells. This peptide also activated the reporter activity of cells transfected with a plasmid harboring a 1-kb fragment corresponding to the 5'-flanking region of the murine iNOS gene. CA(1-8)M(1-18) promoted apoptotic cell death at concentrations below 1 to 2 microM, whereas higher concentrations altered the plasma membrane integrity. These results suggest the involvement of multiple intracellular signaling pathways in the mechanism by which this peptide elicits macrophage triggering.

Acidic pH stress induces protein tyrosine phosphorylation in Leishmania pifanoi

In order to determine whether in vitro Leishmania exposure to conditions comparable to those encountered inside the host cell would induce specific signals, we have studied tyrosine phosphorylation patterns in Leishmania pifanoi. Incubation of L. pifanoi at acidic pH resulted in the phosphorylation of several proteins including three of 27, 43 and 51 kDa, as well as the dephosphorylation of a 175 and a 39 kDa proteins in promastigotes recently transformed. In contrast, heat shock at 37 degrees C did not change the tyrosine phosphorylation pattern. Phosphorylation only occurs at pH 5.0 or lower and reached completion after 1 h. Changes returned to the initial conditions in 2 h after pH medium neutralization, indicating a reversible mechanism of phosphorylation.

Release of lipid vesicle contents by an antibacterial cecropin A-melittin hybrid peptide

A synthetic cecropin A(1-8)-melittin(1-18) hybrid peptide, with antimalarial and antibacterial properties, promotes leakage of aqueous contents of phospholipid vesicles, as determined by measuring the induced release of vesicle-entrapped fluorescence probes. The release of vesicle contents corresponds to an all-or-none mechanism. High molecular weight entrapped solutes (fluorescence-labeled dextrans, 20 and 4 kDa molecular mass) are also released by the peptide. This fact and the high peptide stoichiometry required for the release of vesicle contents suggest a detergent-like disruption of the bilayer. The leakage process is not related to any membrane event requiring lipid-mixing between bilayers. The peptide destabilizes both negatively and neutrally charged phospholipid vesicles. The thermal variation of the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene-labeled vesicles is modified by the peptide. Circular dichroism and tryptophan fluorescence emission spectra reveal conformational changes in the peptide molecule upon interaction with the lipid vesicles. These changes are consistent with an increased alpha-helical content and a less polar environment for the single tryptophan residue of the peptide. The leakage induced in phosphatidylserine vesicles is a faster process than in phosphatidylcholine vesicles, while the peptide is more effective in releasing the contents of the latter type of vesicles. This suggests that acidic phospholipids may modulate the effect of the peptide on membranes.

Ophthalmological tests in patients with keratoconjunctivitis sicca with and without association of primary Sjögren's syndrome

We compared clinical, laboratory and histological tests in patients with keratoconjuctivities sicca with and without association of primary Sjögren's syndrome. Rosa bengal staining, osmolarity and impression cytology had high specificity and sensitivity for a correct diagnosis of keratoconjunctivitis sicca with and without primary Sjögren's syndrome. Schirmer and breakup time (BUT) tests were not quite as specific or sensitive. Impression cytology was the only ocular test that showed significant differences between the two pathological groups.

The biosynthesis, processing, and immunolocalization of Leishmania pifanoi amastigote cysteine proteinases

Biosynthesis, enzymatic processing, and immunocytochemical localization of an abundant developmentally regulated cysteine proteinase of Leishmania pifanoi, Lpcys2, were investigated employing axenic cultured amastigotes and monoclonal antibodies specifically recognizing either the mature proteinase or the carboxy-terminal extension domain. Pulse labeling and protein sequence data indicated that a 45-kDa precursor is processed to a 40-kDa intermediate, which is further cleaved to generate the 27-kDa mature enzyme and a 15-kDa COOH-terminal domain. Evidence indicates that proteolytic activity is associated with the intermediate form as well as the mature proteinase. Treatment with selected cysteine but not aspartic acid proteinase inhibitors arrested proteolytic processing of Lpcys2 in vivo and inhibited parasite cell division. Electron microscopic immunolocalization of both catalytic and COOH-terminal domains in L. pifanoi and Leishmania amazonensis amastigotes showed intense labeling of megasomes, indicating that cleavage of the COOH-terminal domain probably occurs in the megasome. A low level of the mature proteinase was also associated with the flagellar pocket and plasma membrane; consistent with this observation, low level secretion of Lpcys2 into the culture medium was detected. Lpcys1, a related, less abundant amastigote-specific cysteine proteinase lacking a comparable COOH-terminal domain, was localized to the flagellar pocket and megasomes. Consequently, enzyme sorting to megasomes does not appear to depend upon the COOH-terminal domain; hence this region of Lpcys2 may not be essential for its intracellular targeting.

[Extramedullary intracranial solitary plasmocytoma. Report of 2 cases]

Multiple myeloma frequently affects the C.N.S with a high prevalence of spinal cord compression following vertebral neoplastic infiltration. On the other hand, solitary plasmacytomas, tumors that arise in a wide variety of locations due to the universal distribution of plasma cells, are infrequent within the cranial vault and rarely present as extramedullary lesions, arising from the intracranial soft tissues without affecting neighboring bony structures. Only 33 such cases have been reported in the medical literature. The authors report two additional cases of solitary intracranial, extramedullary plasmacytoma. Case 1.--54 year-old woman with a chief complaint of severe headache and behavioral changes of three months duration. C.N.S. imaging revealed a bifrontal mass lesion, arising from the anterior third of the falx cerebri. Case 2.--45 year old-man who complained of headache and blurred vision of a month duration C.N.S. imaging displayed a third ventricle mass lesion. In both cases the neuropathological diagnosis was extramedullary plasmacytoma. Postoperatively the confirmation of solitary intracranial plasmacytoma was achieved only after a thorough work-up to rule out the presence of neoplasm elsewhere in the body. Radiotherapy was given to both patients and follow-up has failed to reveal neoplastic disease 4 and 3 years, respectively, after the diagnosis.

Permeabilization of the mitochondrial inner membrane by short cecropin-A-melittin hybrid peptides

A number of cecropin-A-melittin hybrid peptides have previously been shown to be potent antibacterial agents [Andreu, D., Ubach, J., Boman, A., Wahlin, B., Wade, D., Merrifield, R. B. & Boman, H. G. (1992) FEBS Lett. 296, 190-194]. In the present report we analyze their action on biological systems using rat liver mitochondria as a test system. We demonstrate that the longest peptide, cecropin-A-(1-8)-melittin(1-18) permeabilizes the mitochondrial inner membrane allowing the movement of both charged and non-charged solutes. Concentrations used have already been shown to be bactericidal. This effect is also demonstrated under respiring conditions where succinate oxidation is uncoupled. Shorter analogs also permeabilize mitochondria although at ten-fold higher concentrations. Heparin potentiates the peptide effects at low concentrations, while at high concentration it becomes inhibitory. We propose that the cecropin-melittin analogs disrupt the mitochondrial membrane in a detergent-like mode rather than by creating selective channels as had been previously suggested.

Trypanosoma cruzi: identification of a membrane cysteine proteinase linked through a GPI anchor

The biochemical and functional properties of T. cruzi GP50/55, a novel glycosylphosphatidylinositol (GPI)-anchored membrane antigen have been investigated. A 50-52-kDa thiol proteinase activity could be immunoprecipitated with monoclonal antibodies (mAb) directed against GP50/55 (mAb C10), different from the one reactive with mAbs against lysosomal cysteine proteinase GP57/51. Furthermore, the mAb C10-reactive proteinase corresponded to the GPI-anchored surface antigen since the proteolytic and antigenic activity partitioned to the aqueous phase after Triton X114 phase separation of phosphatidylinositol specific phospholipase C (PI-PLC)-treated parasites. Of several proteins immunoprecipitated by a polyclonal anti-lysosomal cysteine proteinase, an mAb to GP57/51 recognized a 60-kDa protein, whereas mAb C10 recognized antigens ranging between 52 and 50 kDa. The GP50/55 antigen detected by mAb C10 is expressed on the parasite surface whereas the GP57/51 antigen is mainly intracellular. The internal peptide sequence obtained from purified GP50/55 showed that it is more homologous to the prototype of the cysteine proteinases superfamily, papain, than to the two T. cruzi lysosomal cysteine proteinases so far described. Our data indicate that the T. cruzi GP50/55 is a novel GPI-anchored cysteine proteinase and may represent another isoform of this heterogeneous group of proteinases.

Intercostal neuralgia associated with internal mammary artery grafting

Two patients who underwent coronary artery bypass grafting in which the internal mammary arteries were used, developed chronic, atypical chest pain. After further investigation a diagnosis of intercostal neuralgia was made. It is thought that this condition is due to damage to the intercostal nerves when the internal mammary arteries are dissected. Intercostal neuralgia should be included in the differential diagnosis of chest pain after coronary artery surgery, as its recognition may save the patient unnecessary investigation and suffering.

[Primary cardiac hemangioma. A case report and review of the literature]

A 26-years-old woman, without symptoms, was diagnosed of cardiac tumor by means of two-dimensional echocardiography, magnetic resonance imaging and angiocardiography. The tumor was removed underwent open-heart operation and cardiopulmonary bypass. Histologic study was suggestive of a capillary hemangioma. We present our experience with this case and a review of the literature.

Recombinant vaccinia viruses expressing GP46/M-2 protect against Leishmania infection

Leishmania is a genus of parasitic protozoa capable of causing a spectrum of human diseases. The GP46/M-2 membrane glycoprotein has been demonstrated in a murine model system to elicit a protective immune response against infection with Leishmania amazonensis; in highly susceptible BALB/c mice, immunization leads to significant protection against infection. In the present study, for induction of long-term immunological effects, two recombinant vaccinia viruses, derived from the wild type and attenuated variant 48-7 and expressing the GP46/M-2 protein, were constructed; to ensure safety, we used the attenuated vaccinia virus mutant (48-7) as a live vector. Susceptible BALB/c mice immunized with either GP46/M-2-recombinant vaccinia virus were significantly protected against infection with L. amazonensis; 45 to 76% of the animals were completely protected (sterile) against a challenge inoculum of 10(3) infective organisms. The protectively immunized animals demonstrated T- and B-cell-dependent immunological responses; both lymphokine responses as well as antibody responses and long-term memory are indicative of T-cell activation. This first report of the use of a recombinant vaccinia virus to induce protection against a Leishmania infection indicates that recombinant vaccinia viruses should be of value in the design of a safe and effective vaccine against this parasitic disease.

Correlation between impression cytology and tear function parameters in Sjögren's syndrome

We have compared clinical (Schirmer I test, BUT and rose bengal staining), laboratory (lysozyme and lactoferrin tear levels) and histological tests (impression cytology) in 165 eyes from 85 patients with primary Sjögren's syndrome and in 80 eyes from 40 control subjects. Impression cytology can provide the location of cellular alterations on the ocular surface and information on the severity of the disease. The upper bulbar and interpalpebral areas from patients with primary Sjögren's syndrome were shown to have cellular alterations early in the course of the disease, while the lower bulbar and lower palpebral areas were only affected in severe cases. Statistical analysis has shown that impression cytology and rose bengal staining are the most specific and sensitive methods for the diagnosis of primary Sjögren's syndrome.

Developmental life cycle of Leishmania--cultivation and characterization of cultured extracellular amastigotes

The biochemistry and immunology of Leishmania promastigotes has been extensively studied; this is due primarily to the facility with which this stage, in contrast to the amastigotes stage, can be maintained in axenic culture. Several attempts to axenically culture lines of Leishmania amastigotes have been reported in the literature. This paper summarizes methods of adaptation (low pH, elevated temperature and culture medium) and characterization of several axenic lines of Leishmania amastigotes. Based on morphological, biological, immunological and biochemical evidence, these organisms appear to resemble amastigotes from infected macrophages or tissue. The axenically cultured amastigotes appear to be distinct from shocked (heat, serum deprivation, stressed) Leishmania promastigotes in the plethora of proteins synthesized, growth (multiplication) in culture, and developmental regulation observed. These data suggest that Leishmania organisms have a significant developmental response to certain signals (pH, temperature) mimicking their in vivo macrophage milieu. The response to other environmental parameters characteristic of the host-macrophage remain to be determined. These axenically cultured amastigotes should be of interest for further immunological, biochemical and developmental investigations of the disease-maintaining stage of this parasite.

Isolation of two pyruvate kinase activities in the parasitic protozoan Leishmania mexicana amazonensis

Using phosphocellulose affinity chromatography we were able to separate two pyruvate kinase (EC 2.7.1.40) activities in the parasitic protozoan Leishmania mexicana amazonesis. One activity (PYK1) showed hyperbolic kinetics and was decreased by fructose 2,6-bisphosphate, whereas the second activity (PYK2) showed sigmoidal kinetics for the substrate phosphoenolpyruvate and was activated by fructose 2,6-bisphosphate. Molecular sieve chromatography (Sephacryl S-400) of PYK1 produced a single peak of apparent molecular mass around 200,000, while PYK2 eluted at a position corresponding to M(r) 55,000.

Morphological changes in ocular surface in dry eyes and other disorders by impression cytology

A study was conducted on 107 eyes of 70 patients with dry eye disorders and mechanical and chemical extrinsic alterations and 64 eyes of 32 control subjects in order to describe a possible specific response of the conjunctival and corneal surface. We found the presence of "snakelike" chromatin cells and other nuclear changes, squamous metaplasia, and inflammatory cells in the conjunctiva in all groups. A decrease in goblet cell densities was also found in all groups, except for patients with blepharoconjunctivitis. The corneal cells were slightly larger in patients with keratoconjunctivitis sicca.

Biochemical characterization of the protective membrane glycoprotein GP46/M-2 of Leishmania amazonensis

Biochemical features of the immunologically protective, membrane glycoprotein GP46/M-2 of Leishmania amazonensis have been investigated. The protein appears to have a single carbohydrate side chain of approximately 3 kDa, representing 7% of the mass of the mature GP46/M-2 protein. Experiments removing this carbohydrate side chain from GP46/M-2 indicate that the carbohydrate is not involved in the epitope recognized by the monoclonal antibody, M-2. As this monoclonal antibody recognizes a species-specific epitope, these data suggest that this determinant is defined by the polypeptide portion of the molecule. Studies employing the VSG-lipase as well as anti-CRD antibody clearly indicate that the molecule is anchored to the surface membrane of the promastigote via a phosphatidylinositol-linked lipid anchor. Neither the carbohydrate side chain nor the lipid anchor appear to be responsible for the apparent refractoriness of this protein to protease digestion, suggesting that properties of the polypeptide itself may be responsible. These data are discussed in terms of recent DNA-derived protein sequence of the GP46/M-2.

Topographical distribution of ocular surface cells by the use of impression cytology

Cytology impression samples of the conjunctiva and the cornea were obtained from normal eyes. Our results were in agreement with most authors, except in the interpalpebral areas. In the interpalpebral areas, we found new data about superficial cell distribution not described before; the non-secretory cells were more separated and larger, with a higher nuclear-cytoplasmic ratio than other areas. The secretory cells (goblet cells) had significantly decreased with respect to the rest. In the interpalpebral areas, near the limbal areas, no goblet cells were found, and the size of non-secretory cells was increased, the density was lower and the nuclear-cytoplasmic ratio was higher, with regards to the external areas. The corneal epithelial cells had a similar morphological appearance in all specimens tested. We confirm that our subjects were absolutely normal, and conclude that environmental factors might explain why the cells were slightly transformed.

Synthesis of Lectin-Like Protein in Developing Cotyledons of Normal and Phytohemagglutinin-Deficient Phaseolus vulgaris

The genome of the common bean Phaseolus vulgaris contains a small gene family that encodes lectin and lectin-like proteins (phytohemagglutinin, arcelin, and others). One of these phytohemagglutinin-like genes was cloned by L. M. Hoffman et al. ([1982] Nucleic Acids Res 10: 7819-7828), but its product in bean cells has never been identified. We identified the product of this gene, referred to as lectin-like protein (LLP), as an abundant polypeptide synthesized on the endoplasmic reticulum (ER) of developing bean cotyledons. The gene product was first identified in extracts of Xenopus oocytes injected with either cotyledonary bean RNA or LLP-mRNA obtained by hybrid-selection with an LLP cDNA clone. A tryptic map of this protein was identical with a tryptic map of a polypeptide with the same SDS-PAGE mobility detectable in the ER of bean cotyledons pulse-labeled with either [(3)H]glucosamine or [(3)H]amino acids, both in a normal and in a phytohemagglutinin-deficient cultivar (cultivars Greensleeves and Pinto UI 111). Greensleeves LLP has M(r) 40,000 and most probably has four asparagine-linked glycans. Pinto UI 111 LLP has M(r) 38,500. Unlike phytohemagglutinin which is a tetramer, LLP appears to be a monomer by gel filtration analysis. Incorporation of [(3)H]amino acids indicates that synthesis of LLP accounts for about 3% of the proteins synthesized on the ER, a level similar to that of phytohemagglutinin.

Comparative study on polypeptide patterns of larvae of Trichinella isolates by two-dimensional electrophoresis

The two-dimensional patterns (isoelectrofocusing-IEF/polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate-SDS) of S3 fractions of muscle larvae of four Trichinella isolates were compared. The comparative study concerned six groups of polypeptides. It was observed that the Garkavi isolate of Trichinella pseudospiralis was clearly different from the other isolates, and it showed the simplest IEF/SDS polypeptide pattern. The C-76 isolate of T. nelsoni had only four of the six groups, distinguishing it from the GM-1 isolate of T. spiralis and the Boev isolate of T. nativa that showed all the indicated groups.

Evidence for common antigens on human non-adherent synoviocytes (type A) and peripheral monocytes

The characterization of a homogeneous non-adherent synoviocyte (Type A) cell population (greater than or equal to 95%) from non-rheumatoid patients by culturing the cells in the presence of forty percent foetal calf serum is reported. These cells were able to phagocyte latex beads, iron particles, fluoresceinated zymosan and yeast. Furthermore, non-adherent synoviocytes were capable of being infected by the obligate intracellular parasite of peripheral monocytes Leishmania donovani. Indirect immunofluorescence experiments with specific anti-human monocyte (OKM1) antibody and specific antisynoviocyte serum, showed the presence of common surface structures between synoviocytes A cells and peripheral monocytes. Fifty five percent of the synoviocytes were also positive for HLA Dr antiserum. Analysis by two dimensional gel electrophoresis showed that peripheral monocytes and synoviocytes secreted identical polypeptides in vitro. These results strongly suggest a relationship between synoviocytes A and mononuclear phagocyte system.

White light-electromagnetic field interaction causes a localized destruction of cultured HeLa cells

Filming of cultured HeLa cells using time-lapse cinevideomicrography techniques, with exposure to an extremely low frequency electromagnetic field allowed the direct observation of a localized cellular destruction process caused by a white light-electromagnetic field interaction. This phenomenon was not observed with normal human fibroblasts.

The antenna system of Rhodospirillum rubrum. Detection of macromolecular constituents not stainable by Coomassie brilliant blue in solubilized preparations of the B880 complex

A solubilized preparation of the major Rhodospirillum rubrum antenna complex (B880) was obtained by a described procedure and its polypeptide composition was analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Only two polypeptides of molecular weights close to 7000 were detected after staining the gels with Coomassie brilliant blue. However, several other constituents could be visualized by silver staining or by an immunochemical method. When the preparation was chromatographed on Sephacryl, some of the resulting fractions exhibited the characteristic B880 absorption spectrum and contained only the two proteins that were detectable with Coomassie brilliant blue. In those fractions the A 280/A 880ratio was 0.4, which indicated a significant improvement of the bacteriochlorophyll to protein ratio over the unchromatographed preparation (A 280/A 880=0.7). Other chromatography fractions lacked bacteriochlorophyll and contained a carotenoid which seemed to be bound to protein. The macromolecular constituents present in these latter fractions differed from those associated to the purified B880 complex in their electrophoretic moblities and/or in their staining properties. That suggested the possible existence of a carotenoprotein that did not result from the B880 complex upon loss of bacteriochlorophyll.

Topography of the subunits of Micrococcus lysodeikticus F1-ATPase

The combined use of proteolytic digestion and lactoperoxidase catalyzed labelling with [125I] applied to membrane-bound or soluble pure F1-ATPase from Micrococcus lysodeikticus has allowed us to establish the topography of its alpha, beta, gamma and delta subunits within the protein molecule and with respect to the plane of the membrane. The beta subunit is most externally located to the membrane bilayer looking towards the cytoplasmic face, a position consistent with its proposed catalytic role. The alpha and gamma subunits lie in an intermediate layer between the beta subunits and the membrane, in which the gamma subunit occupies a central position within the F1-ATPase molecule in contact with the alpha subunit. The delta subunit appears to be tightly bound to the F0 component of the ATPase complex, probably buried in the membrane bilayer. A molecular arrangement of M. lysodeikticus ATPase is proposed that, taking into account the subunit stoichiometry alpha 3 beta 3 gamma 2 delta 2 (MW 420 000), accommodates the role assigned to each subunit and most, if not all, the known properties of this bacterial energy-transducing protein.

Partial characterization of membrane-associated proteinases from Micrococcus lysodeikticus

We have identified cytoplasmic and membrane-associated proteinases from Micrococcus lysodeikticus (M. luteus) by the use of 125I-labeled casein and insulin as substrates. The membrane-associated activities were released by shock washing. Proteolytic activities showed pH optima at slightly alkaline values and we have concentrated on the activities at pH 8.0. The total units of both proteolytic activities were higher in the cytoplasmic than in any other fractions but the situation was different when the results were expressed in terms of specific activity. The activities against casein and insulin were differentiated by the action of inhibitors, divalent metal ions, Arrhenius plots and dependence on ionic strength. On these grounds, it is proposed that the membrane-associated enzyme acting on insulin is a single thiol proteinase while the proteolysis of casein reflects the action of, at least, two enzymes (thiol proteinase and serine proteinase). The distinction between the casein and insulin degrading activities was confirmed by crossed-inhibition experiments and by their behaviour on gel chromatography and concentration-dependence experiments. The aggregating properties have hampered the purification of the enzymes. The present results raise doubts about the significance of preventing membrane damage and degradation of membrane proteins by the addition of indiscriminated proteinase inhibitors during membrane isolation and manipulation.