Bioprosthetic valve fracture during valve-in-valve transcatheter aortic valve replacement: multicenter propensity matched analysis

Background

Valve-in-valve (ViV) transcatheter aortic valve implantation (TAVI) can be completed by bioprosthetic valve fracture (BVF) to reduce final transvalvular gradients. The aim was to compare outcomes in ViV-TAVI patients with versus without BVF.

Methods

Consecutive patients undergoing ViV-TAVI procedure in four international centers were included, from 2010 to 2021. We used a 1:2 propensity score-matching method to compare postprocedural hemodynamic, complications, and long-term outcomes. Patients were matched for baseline characteristics, time since prior surgery, and characteristics of surgical bioprothesis (type and size).

Results

A total of 390 patients were analyzed, including 40 BVF. Propensity matching 1:2 yielded 38 patients in BVF group and 76 patients in no-BVF group. There was no difference in procedural complications rate and in-hospital deaths (5.1%) between the two groups. Post-procedural hemodynamic parameters significantly improved using BVF: aortic valve area (1.4 cm2 [IQR: 1.23 to 2.3] vs. 1.3 cm2 [IQR: 1.05 to 1.61], p=0.008), mean aortic gradient (12mmHg [IQR: 7.5 to 16.5] vs. 17mmHg [IQR: 11 to 22], p=0.008) and peak velocity (2.2m/s [IQR: 1.8 to 2.7] vs. 2.6m/s [IQR: 2.2 to 3.1], p=0.027). BVF had an additional benefit in the smallest surgical valve (≤21 mm). The use of BVF was independently associated with improved hemodynamic parameters. Overall survival in the matched cohort was 87.8±3.7% at 2-year follow-up, without difference between groups (87.5±6.9% in the BVF group vs. 88.4±4.2% in the no-BVF group, p=0.85).

Conclusion

Compared to ViV-TAVI alone, BVF was safe and improved immediate hemodynamic and long-term outcomes, especially in patients with small surgical aortic bioprosthesis.

Funding Acknowledgement

Type of funding sources: None.

Patterns of left ventricular longitudinal myocardial dysfunction in mitral valve prolapse and effects of valve repair

Background

Regional longitudinal left ventricular (LV) dysfunction in patients with mitral regurgitation (MR) due to valve prolapse (MVP) with normal ejection fraction has been recently described, with data pointing at dysfunction of the LV base related to dilatation of the mitral annulus.

Purpose

To investigate degree and extent of regional LV dysfunction and its mechanisms in patients with MVP and severe acute (MRa, n=27) or chronic (MRc, n=41) MR and no coronary disease, undergoing surgical valve repair with 3 months follow-up (FU); 20 normal subjects were used as controls (N).

Methods

Speckle-tracking echocardiography was performed pre- (Bas), 1 week (1w) and 4 months (4mo) post-operatively to measure longitudinal global (GLPSS, %), regional (RPSS, %) and segmental (SPSS) peak systolic strain. Maximum and minimum mitral annulus (MA) diameters were measured with 3D echo at Bas. We also evaluated: LV end-diastolic volume index (EDVi, ml/m2); ejection fraction (EF, %); left atrial end-systolic volume index (LAVi, ml/m2); non-invasive pulmonary systolic pressure (PSP, mmHg).

Results

Risk factors (hypertension, diabetes, atrial fibrillation, smoke and previous stroke) were similar in MRc and MRa. At Bas EDVi was larger by definition in MRc (MRc: 102±21, MRa: 67±10 ml/m2, p<0.001) as LAVi (101±46 vs 76±31 ml/m2, p=0.035). Both EF (65±8 vs 64±8 ml/m2) and GLPSS (−20±4 vs −21±5%) were normal, but RPSS was reduced, only at the base (−13±6 vs −13±6%, p= ns; N: −18±2, p<0.03 vs MRc and MRa) in MRc and MRa, with reduced SPSS localized at anterior, lateral and posterior – but not septal – segments. At 1w, EF decreased in both MRc (47±14%, p<0.001 vs Bas) and MRa (56±10%, p=0.014 vs Bas), together with GLPSS (MRc: −11±4%, p<0.001 vs Bas; MRa; −13±4, p<0.001 vs Bas) driven by a prevalent marked decrease in RPSS (MRc: −7±4%, p<0.001 vs Bas; MRa; −8±5, p<0.001 vs Bas) of the LV base. All patients were alive at 3 months with no MACEs, similar reduction of mean MR grade (MRc: 4±0 to 1.9±0.7, p<0.001; MRa: 3.9±0.3 to 0.9±0.9, p<0.001) and PSP (MRc: 50±23 to 29±5 mmHg, p<0.001; MRa: 42±22 to 32±6 mmHg, p=0.039), normal EDVi (MRc: 70±27, MRa: 49±10 ml/m2), dilated LAVi (MRc: 101±46, MRa: 54±13 ml/m2), and reduced GLPSS (MRc: −12±5%, p<0.001 vs Bas; MRa; −15±3, p=0.001 vs Bas) and base RPSS (MRc: −7±6%, p=0.004 vs Bas; MRa; −10±4, p= ns vs Bas). At multivariate analysis, regional dysfunction was not related to the prolapsing scallop, presence of flail, commissure involvement, dimension and geometry of the MA, EF or pulmonary pressures.

Conclusions

In patients with MVP and severe MR, there is a specific regional longitudinal dysfunction pattern prevalent at the LV base which may be related to the duration of MR but not to annular dilatation or morphology of the prolapsing leaflets. The dysfunction worsens greatly following acute reduction of preload after surgical repair and is still significant at 4mo FU.

Funding Acknowledgement

Type of funding source: None

Bartonella-related pseudomembranous angiomatous papillomatosis of the oral cavity associated with allogeneic bone marrow transplantation and oral graft-versus-host disease

Patients undergoing allogeneic stem cell transplantation are at high risk for infection with a variety of pathogens during different phases of the procedure. Human infections due to Bartonella spp. are viewed as emerging diseases typical in, although not exclusive to, immunosuppressed patients, in particular those with AIDS, organ transplants and haematological malignancies. We describe four patients, three children and one adult, who developed vegetating papillomatous lesions exclusively on the oral mucosae. They shared a history of haematological malignancy and allogeneic bone marrow/stem cell transplantation, and later developed chronic graft-versus-host disease, also involving the oral mucosae. Histopathologically, the vegetating lesions were characterized by a diffuse neoangiogenesis, granulation-like tissue, and a mixed cell infiltrate predominantly composed of neutrophils. Gram-negative bacteria were found in the endothelial cells of the vessels in the deeper portion of the corium by electron microscopy. In three cases, DNA of B. henselae was detected by polymerase chain reaction (PCR), and confirmed by sequencing of the PCR products. All the lesions healed after systemic antibiotic therapy, although some recurred after months, and regressed again after systemic antibiotic treatment associated with conservative surgical excision.

The Intradermal Leishmanin Reaction Induces Antigen-specific Maturation of Canine Dendritic Cells with Up-regulation of MHCII Synthesis and Expression

Dendritic cells (DCs) are professional antigen-presenting cells that reside in many tissues, including the skin. This study showed that intradermal injection of leishmanin in Leishmania infantum-infected dogs induced the "up-regulation" of surface MHCII expression, associated with progressive ultrastrucutural changes characteristic of DC maturation, including the formation of multilaminar MHC class II-containing compartments and arrays of tubulo-vesicular structures. These changes were not observed in control dogs from L. infantum non-endemic areas. The results indicated that canine DCs were effector cells in delayed-type hypersensitivity, that the leishmanin reaction was specific for a cell-mediated reaction to L. infantum in infected dogs, and that canine DCs possessed ultrastructural organelles reminiscent of those in activated human DCs.

A symbiont of the tick Ixodes ricinus invades and consumes mitochondria in a mode similar to that of the parasitic bacterium Bdellovibrio bacteriovorus

We have recently performed molecular characterisation of an intracellular alpha-proteobacterium, named IricES1, which resides in the ovarian tissue of female Ixodes ricinus ticks from Italy. A unique characteristic of this bacterium is its ability to invade the mitochondria of the cells in which it resides. Although some ultrastructural studies have been performed on close relatives of this bacterium from I. ricinus in England and Switzerland, a number of questions remain about its movement within ovarian tissues and mitochondria. We have performed the first detailed ultrastructural examination of IricES1 in engorged female adult I. ricinus. Among our findings was that the bacterium enters mitochondria in a similar way to that employed by the 'predatory' bacterium Bdellovibro bacteriovorus, that is, between the inner and outer membranes. It then appears to multiply, with the new 'colony' consuming the mitochondrial matrix. Despite having many of their mitochondria consumed, oocytes appear to develop normally, and the bacteria are likely to be vertically transferred to all eggs.

Ultrastructural evidence of the degenerative events occurring during embryogenesis of the filarial nematode Brugia pahangi after tetracycline treatment

Intracellular bacteria belonging to the genus Wolbachia have been described in filarial nematodes and these microorganisms appear to have evolved an obligatory mutualistic association with their filarial hosts. In fact, antibiotic treatment leads to the clearance of bacteria from worms resulting in a block in embryogenesis and, eventually, death of adult filariae. Currently, the antifilarial action of antibiotic treatment is interpreted as a secondary consequence of the bacteriostatic activity against Wolbachia endosymbionts. Here, we demonstrate by transmission electron microscopy the degenerative events occurring during embryogenesis of Brugia pahangi after tetracycline treatment. After 56 days of treatment the cytoplasm of hypodermal cords was totally void of Wolbachia and numerous vacuoles, residual of cytolitic activity, were observed. In the ovary, the morphology of the oocytes was well conserved 33 days after treatment, but the texture of symbiotic bacteria appeared altered. After 56 days of treatment embryogenesis was dramatically affected and the terminal portion of the ovary appeared totally empty. The authors suggest that the symbiotic bacteria play a direct role in worm metabolism and a long-term bacteriostatic effect may block bacterial activity involved in the active control of cytolysis. As a consequence, the bacteriophorous vacuole is transformed into a digestive vacuole and the whole symbiotic population is disrupted.

Immunohistochemical/immunogold detection and distribution of the endosymbiont Wolbachia of Dirofilaria immitis and Brugia pahangi using a polyclonal antiserum raised against WSP (Wolbachia surface protein)

Intracellular bacteria in filarial nematodes were described as early as the 1970s, yet it was only with the work on Dirofilaria immitis, the agent of canine and feline heartworm disease, that these microorganisms were identified as belonging to Wolbachia, a genus known for encompassing bacteria infecting insects and other arthropods. The implications for the presence of intracellular bacteria in filarial nematodes is now the subject of intense research, particularly regarding their role in the immunology and pathogenesis of disease in infected humans and animals and as a possible target for therapy. Here, the authors report results on the immunohistochemical and immunogold staining of Wolbachia in D. immitis and Brugia pahangi using polyclonal antibodies raised against the recombinant Wolbachia surface protein (WSP). The bacteria were present in the lateral hypodermal chords of both male and female worms and in the reproductive tract of adult females (oocytes, morulae, microfilariae). In D. immitis and B. pahangi from animals treated with tetracycline, positive staining was observed in the lateral chords of adult males and females, but was absent from the oocytes and morulae. These results indicate that Wolbachia endosymbionts can be identified immunohistochemically with anti-WSP polyclonal antibodies, that their distribution matches that already described for Wolbachia of other filarial worms, and that antibiotic treatment may impede the vertical transmission of these bacteria. Unequivocal detection of Wolbachia is essential for the study of this symbiont, in particular to monitor the effects of antibiotic treatment on worms. The use of a specific marker for bacteria in their nematode hosts represents an extremely useful tool in evaluating the pathogenic role and the effect of antibiotic treatment on these potential targets in the control of filarial disease.

Trichinella zimbabwensis n.sp. (Nematoda), a new non-encapsulated species from crocodiles (Crocodylus niloticus) in Zimbabwe also infecting mammals

Since 1995, Trichinella larvae have been detected in 39.5% of farmed crocodiles (Crocodylus niloticus) in Zimbabwe. Morphological, biological, biochemical and molecular studies carried out on one isolate from a farmed crocodile in 2001 support the conclusion that this parasite belongs to a new species, which has been named Trichinella zimbabwensis n.sp. This species, whose larvae are non-encapsulated in host muscles, infects both reptiles and mammals. The morphology of adults and larvae is similar to that of Trichinella papuae. Adults of T. zimbabwensis cross in both directions with adults of T. papuae (i.e. male of T. zimbabwensis per female of T. papuae and male of T. papuae per female of T. zimbabwensis), producing F1 offspring which produce very few and less viable F2 larvae. Muscle larvae of T. zimbabwensis, like those of T. papuae, do not infect birds. Three allozymes (of a total of 10) are diagnostic between T. zimbabwensis and T. papuae, and five are diagnostic between T. zimbabwensis and Trichinella pseudospiralis, the third non-encapsulated species. The percentage of the pairwise alignment identity between T. zimbabwensis and the other Trichinella species for the cytochrome oxidase subunit I gene, the large subunit ribosomal-DNA (mt-lsrDNA) gene and the expansion segment five, shows that T. zimbabwensis is more similar to the two non-encapsulated species T. papuae (91% for cytochrome oxidase I; 96% for mt-lsrDNA; and 88% for expansion segment five) and T. pseudospiralis (88% for cytochrome oxidase I; 90% for mt-lsrDNA; and 66-73% for expansion segment five) than to any of the encapsulated species (85-86% for cytochrome oxidase I; 88-89% for mt-lsrDNA; and 71-79% for expansion segment five). This is the first non-encapsulated species discovered in Africa. The finding of a new Trichinella species that infects both reptiles and mammals suggests that the origin of Trichinella parasites dates back further than previously believed and can contribute to understanding the phylogeny and the epidemiology of the genus Trichinella.

Does fertilization in the filarial nematode Dirofilaria immitis occur through endocytosis of spermatozoa?

Information on the ultrastructural details of fertilization in filarial nematodes are still unavailable. Here we report new data on this process in Dirofilaria immits, the heartworm of dogs and cats. Electron microscopy allowed us to observe oocytes engulfing spermatozoa through an endocytosis-like process. We also observed spermatozoa inside the oocytes which still possessed their plasma membrane and which were clearly enveloped by a further membrane, likely derived from the endocytosis process. At this stage, at the interface between the sperm membrane and the endocytotic membrane (vacuolar space), we observed flocculent material in the proximity of the membranous organelles (MOs) of the sperm. In the proximity of the MOs, we also observed the enlargement of the vacuolar space. Other images showed the dissolution of the sperm membrane, and the release of nuclear masses and organelles in the egg cytoplasm. We did not observe the fusion of lysosomes to the endocytotic vacuoles. In addition, the lysis of the sperm organelles has never been observed inside the vacuoles containing the whole sperm. Thus we suggest that the degradation of the endocytotic and sperm plasma membranes is determined by material released by the MOs. Since we did not observe the entry of sperm into the oocytes by other mechanisms, we also suggest that endocytosis is the normal process used by the spermatozoon to get into the egg cytoplasm in D. immitis. Finally, during our observations of the seminal receptacle we did not observe any structure in the spermatozoa which could be interpreted as an intracellular bacterium. This is consistent with previous results indicating that the bacterium Wolbachia in filarial nematodes is not transmitted through the sperm.

Ultrastructural characteristics of nurse cell-larva complex of four species of Trichinella in several hosts

The nurse cell-larva complex of nematodes of the genus Trichinella plays an important role in the survival of the larva in decaying muscles, frequently favouring the transmission of the parasite in extreme environmental conditions. The ultrastructure of the nurse cell-larva complex in muscles from different hosts infected with T. nativa (a walrus and a polar bear), T. spiralis (horses and humans), T. pseudospiralis (a laboratory mouse) and T. papuae (a laboratory mouse) were examined. Analysis with transmission electron microscope showed that the typical nurse cell structure was present in all examined samples, irrespective of the species of larva, of the presence of a collagen capsule, of the age of infection and of the host species, suggesting that there exists a molecular mechanism that in the first stage of larva invasion is similar for encapsulated and non-encapsulated species.

Familial benign recurrent vertigo

Benign recurrent vertigo (BRV) has been previously linked to migraine but there have been no prior studies of families with BRV. We studied the families of 24 patients who presented to our clinic with BRV and who reported a family history of similar attacks of vertigo. All probands underwent diagnostic evaluation to exclude identifiable causes of recurrent vertigo and they completed a standardized medical questionnaire pertaining to episodic vertigo and the features of migraine. This questionnaire was also sent to all relatives of the probands who agreed to participate. Of 220 relatives who returned questionnaires, 37% reported BRV and 50% met the diagnostic criteria for migraine. By contrast, only one of 43 (2%) unrelated spouses reported BRV and 10 of 43 (23%) met the diagnostic criteria for migraine. More than two-thirds of relatives with BRV met the diagnostic criteria for migraine and the majority reported that they had a typical migraine headache with at least some of their episodes of vertigo. Both BRV and migraine showed a female preponderance (more than 2 to 1). Familial BRV seems to be a migraine syndrome, probably inherited in an autosomal dominant fashion with decreased penetrance in men. In the search for the causative gene, vertigo may be a more useful marker than migraine because recurrent vertigo is relatively rare in the general population whereas migraine is very common.

In vitro efficacy of nikkomycin Z against the human isolate of the microsporidian species Encephalitozoon hellem

Since 1985 microsporidia have been recognized as a cause of emerging infections in humans, mainly in immunocompromised human immunodeficiency virus-positive subjects. As chitin is a basic component of the microsporidian infective stage, the spore, we evaluated in vitro the susceptibility of a human-derived strain of Encephalitozoon hellem to nikkomycin Z, a peptide-nucleoside antibiotic known as a competitive inhibitor of chitin synthase enzymes. Transmission electron microscopy showed that this drug, at 25 microgram/ml, reduced the number of parasitic foci by about 35% +/- standard deviation after 7 days of culture (P < 0.0001) and induced cell damage of both mature and immature spores and also other sporogonic and merogonic stages. In particular, an irregular outline of the cell shape and an abnormally condensed cytoplasm in meronts and sporonts were documented. Also, the polar tubule and the polaroplast membranes appeared disarrayed in the sporoblast stage. The spore wall showed an enlarged endospore and delaminated exospore. Mature spores had a complete cytoplasmic disorganization and a swollen and delaminated cell wall. No ultrastructural cell damage was observed in uninfected control cultures treated with the drug.

Trichinella papuae n.sp. (Nematoda), a new non-encapsulated species from domestic and sylvatic swine of Papua New Guinea

Encapsulated and non-encapsulated species of the genus Trichinella are widespread in sylvatic animals in almost all zoogeographical regions. In sylvatic animals from Tasmania (Australian region), only the non-encapsulated species Trichinella pseudospiralis has been reported. Between 1988 and 1998, non-encapsulated larvae of Trichinella were detected in five domestic pigs and six wild boars from a remote area of Papua New Guinea. Morphological, biological, and molecular studies carried out on one strain isolated from a wild boar in 1997 suggest that these parasites belong to a new species, which has been named Trichinella papuae n.sp. This species can be identified by the morphology of muscle larvae, which lack a nurse cell in host muscles, and whose total length is one-third greater than that of the other non-encapsulated species, T. pseudospiralis. Adults of T. papuae do not cross with adults of the other species and genotypes. Muscle larvae of T. papuae are unable to infect birds, whereas those of T. pseudospiralis do. The expansion segment V of the large subunit of the ribosomal DNA differs from that of the other species and genotypes. All of these features allow for the easy identification of T. papuae, even in poorly equipped laboratories. The discovery and identification of a second non-encapsulated species in the Australian region strongly supports the existence of two evolutionary lines in the genus Trichinella, which differ in terms of the capacity of larvae to induce a modification of the muscle cell into a nurse cell.

Experimental respiratory cryptosporidiosis in immunosuppressed rats: a light and electron microscopy study

Cryptosporidium parvum is a coccidian protozoon that causes diarrhoeal enteritis in immunocompetent and immunocompromised humans and other mammals. Sometimes, chiefly in HIV-infected subjects, anatomical sites other than gastro-intestinal tract, such as the biliary and respiratory tree, are involved. We performed an experimental respiratory infection in immunosuppressed albino rats with a C. parvum human-derived isolate, to confirm the possibility of a primary infection at this site and to evaluate the protozoan damages by light and also by transmission electron microscopy (TEM). The animals were infected intratracheally with 1 x 10(6) C. parvum oocysts/ml and, from the 7th day post-infection, biological specimens of trachea, bronchi, lung and ileum were zoopsied. A sole cryptosporidial colonization of the respiratory tract, from the trachea to the median bronchi, without lung parenchyma infection, was observed. Moreover 13/33 (39.4%) rats also developed intestinal infection. TEM study of the respiratory tree specimens demonstrated that cryptosporidia infect either ciliated or goblet cells, and confirmed the role of microvilli in the parasite cell adhesion. The most relevant alterations involved the ciliated cells, with loss of cilia and nuclear and cytoplasmic damages.

Effects of tetracycline on the filarial worms Brugia pahangi and Dirofilaria immitis and their bacterial endosymbionts Wolbachia

Wolbachia endosymbiotic bacteria have been shown to be widespread among filarial worms and could thus play some role in the biology of these nematodes. Indeed, tetracycline has been shown to inhibit both the development of adult worms from third-stage larvae and the development of the microfilaraemia in jirds infected with Brugia pahangi. The possibility that these effects are related to the bacteriostatic activity of tetracycline on Wolbachia symbionts should be considered. Here we show that tetracycline treatment is very effective in blocking embryo development in two filarial nematodes, B. pahangi and Dirofilaria immitis. Embryo degeneration was documented by TEM, while the inhibition of the transovarial transmission of Wolbachia was documented by PCR. Phylogenetic analysis on the ssrDNA sequence of the Wolbachia of B. pahangi confirms that the phylogeny of the bacterial endosymbionts is consistent with that of the host worms. The possibility that tetracycline inhibition of embryo development in B. pahangi and D. immitis is determined by cytoplasmic incompatibility is discussed.

Some aspects of intracellular symbiosis during embryo development of Mastotermes darwiniensis (Isoptera: Mastotermitidae)

All examined species of cockroaches have been shown to harbour intracellular bacteria in specialized cells (bacteriocytes) of the fat body. In termites, bacteria in specialized cells have been observed only in Mastotermes darwiniensis (Isoptera: Mastotermitidae). All of these bacteria have been assigned to the same eubacterial lineage, with the bacteria of M. darwiniensis as the sister group to the cockroach bacteria. While the main steps of the life cycle of cockroach bacteria have been described, little is known about the bacteria of M. darwiniensis. More specifically, no data are available on their behaviour during the development of this termite. Using both optical and electron microscopy methods, we examined embryos of M. darwiniensis at different developmental stages. Our results show that the integration of bacteria during the development of M. darwiniensis is implemented in the same way as in cockroaches. In particular, we observed the aggregation of a large amount of bacteria in a single mass in the yolk sac, with vitellophage-associated bacterial lysis. In cockroaches, a similar process has been described in detail for Periplaneta americana (Blattaria: Blattidae), where the bacterial mass is referred to as the transitory mycetome. The formation of a transitory mycetome could thus be regarded as an ancestral condition for cockroaches and termites.

Balance disorders in older persons: quantification with posturography

We measured sway velocity using static and dynamic posturography in a group of young normal subjects and two groups of subjects older than 75 years; one older group considered their balance normal for their age, and the other reported imbalance. The latter group consisted of patients with documented peripheral and central vestibular disorders and patients with dizziness and imbalance of unknown cause. The velocity of sway was higher in older subjects than in younger subjects and in older subjects who reported imbalance than in age-matched controls. The difference was greater with dynamic posturography than with static posturography, but the posturography data provided little information about the cause of the imbalance and did not correlate with the frequency of reported falls.

Mechanisms of microsporidial cell division: ultrastructural study on Encephalitozoon hellem

The mitotic process in microsporidian Encephalitozoon hellem, a known human pathogen, has been studied with the aim of elucidating some ultrastructural aspects of its nuclear division. The presence of a nuclear spindle, of "electrondense spindle plaques" associated with the nuclear envelope and of cytoplasmic double walled vesicles are reported. We suggest that these "electrondense spindle plaques" serve as foci for intranuclear and cytoplasmic microtubule arrangements, similar to the microtubule organizing centers within the centrosomes of animal cells. The extent to which the microsporidial division process is comparable with that of more familiar eukaryotes such as yeast cells is discussed.

A prospective study of posturography in normal older people

OBJECTIVE

To follow posturographic measurements over time in a group of normal older subjects to see if sway increases with aging and if sway is greater in those with deteriorating balance and falls.

SUBJECTS

Seventy-two community-dwelling older people (age range 79-91 years), who initially had normal neurological evaluations, were followed with three yearly follow-up examinations.

MEASUREMENTS

Amplitude and velocity of sway on static and dynamic posturography, Tinetti gait and balance score, reports of falls.

RESULTS

Velocity of sway on dynamic tests increased significantly during the 3 years of follow-up. The percentage increase in sway was about the same in the anterior-posterior and medial-lateral directions and with eyes open and eyes closed. Subjects with low Tinetti scores had higher sway amplitude and velocity, particularly on dynamic tests, but no measure of sway was significantly different in those who reported falls compared with those who did not report falls.

CONCLUSIONS

Sway increases in normal subjects over time, and sway is greater in older subjects with deteriorating balance compared with those with normal balance. Sway was not greater in those who fell compared with those who did not fall, probably because falls are highly dependent on individual behavior.

Mediterranean leishmaniasis in HIV-infected patients: epidemiological, clinical, and diagnostic features of 22 cases

Twenty-two Italian HIV-infected patients developed leishmaniasis, clinically manifested as visceral (13 cases), cutaneous (2 cases) and disseminated disease (7 cases). Twenty were males and two females (mean age: 32.8 years) with a mean CD4+ cell count of 46.8/microliter at diagnosis; risk factors were intravenous drug use (17 patients) and sexual behaviour (two bisexual, two homosexual, one heterosexual). All but one patient lived or travelled in hypoendemic Italian regions and other Mediterranean countries. Apart from the two patients with cutaneous leishmaniasis, the clinico-pathological and biological spectrum of the infection was often atypical, especially in patients with disseminated disease. The diagnosis was routinely made by direct recovery of parasites in biological specimens, mainly in bone marrow aspirate, whereas serology was negative or borderline in most of the patients. Among 17 in vitro isolates, Leishmania infantum was the only species involved with previously undescribed isoenzyme patterns in two cases. Treatment with antimonials and other drugs showed only temporary clinical improvement in some patients. Relapses were the rule. Leishmaniasis confirms itself as an opportunistic infection in HIV-positive persons. Secondary chemoprophylaxis should be considered in cases of relapsing disease.

Distribution of Trichinella spiralis larvae in muscles from a naturally infected horse

Epidemiological investigations conducted during 10 trichinellosis outbreaks between 1975 and 1994 showed that horse-meat was the probable source of infection. Though hundreds of thousands of horses have been examined at abattoirs in America and Europe to detect Trichinella infection by artificial digestion or trichinelloscopy, an infected horse has never been detected during routine analysis, which consists of examining 1 g of tissue muscle from the diaphragm. In November 1996, a naturally infected horse imported from Romania was detected in Southern Italy. The parasite was identified as Trichinella spiralis by random amplified polymorphic DNA analysis. Artificial digestion of tissue samples from 60 different muscles from 13 different sites of the infected horse carcass showed that M. levator Labii maxillaris, M. hyoideus transversus, and M. buccinator were the 3 most infected muscles. Muscles from the tongue, the masseter, and the diaphragm, which have normally been considered the muscles of choice for diagnosis, were the 4th, 6th and 13th most infected muscles, respectively. When comparing body sites, muscle tissues from the head showed the highest level of infection, followed by muscles from the neck. This finding may explain the negative results that have been obtained in the past during routine examination of the diaphragm of horses.

Asymptomatic respiratory tract microsporidiosis due to Encephalitozoon hellem in three patients with AIDS

Microsporidia of the genera Enterocytozoon and Encephalitozoon have been identified as frequent causes of intestinal and disseminated infections, respectively, in patients with AIDS. Even though most subjects infected with these protozoa develop overt disease, simple colonization without illness may occur, as we observed in three severely immunosuppressed patients with AIDS. The parasites, recognized in and isolated from bronchoalveolar lavage sediment specimens, were characterized as Encephalitozoon hellem. Colonization of the bronchial tree was temporary, and treatment with albendazole was not needed to clear the infection.

Detection of Trichinella spiralis in a horse during routine examination in Italy

Routine examination for Trichinella infection by artificial digestion of 5-g samples of muscle tissue revealed the presence of muscle larvae in one out of 28 horses imported from Romania to an abattoir in Italy. The parasite, identified as Trichinella spiralis by the polymerase chain reaction, showed a reproductive capacity index of 68 in Swiss mice. Light microscope examination of 200 nurse cell-larva complexes showed that 22% of them were calcified and that the capsules of the non-calcified nurse cells were 17.5-27.5 microns (s = 22.67 microns) thick and had very few cellular infiltrates. The serum samples from the parasitologically positive horse and from three other horses of the same stock, from which Trichinella larvae were not recovered by digestion, showed a low level of positivity as determined by ELISA and Western blot analyses using a crude antigen, whereas negative results were observed in both tests when an excretory-secretory antigen was used. The results, together with data from the literature, suggest that the horse had acquired the infection 8-10 months previously and confirm earlier observation obtained from experimental infections, which showed that muscle worm burden and specific circulating antibodies were lost several months after infection.

Ultrastructural features of spindle microtubule organization during the nuclear division of Encephalitozoon hellem

Ultrastructural studies were carried out to describe the nuclear division cycle of a strain of Encephalitozoon hellem isolated from an Italian AIDS patient. The nuclear division occurs during the proliferative vegetative phase and it is characterized by the intranuclear mitosis and by the lack of centrioles. The spindle termini are electron dense spindle plaques (ESPs), resembling to the spindle pole bodies (SPBs) of Saccharomycetes. The ESPs are bifacial organella forming microtubules on both nucleoplasic and cytoplasmic faces. In the outer layer of the spindle plaque are present vesicular elements lined by a double membrane of unknown function. The peculiar morphological features of E. hellem ESPs indicate that both intranuclear spindle and cytoplasmic microtubules are involved in the nuclear division.

Occurrence of apoptosis in serosa of Periplaneta americana l. (Blattaria: blattidae): ultrastructural and biochemical features

In 16-17-day-old embryos of Periplaneta americana, the amnion-serosa penetrates the cavity of the middle intestine, where it forms a cluster of compressed roundish cells. We demonstrated that these cells degenerate throughout apoptosis. The programmed cell death revealed by morphological and biochemical approaches showed all the apoptotic steps: chromatin fragmentation and pyknosis, cytoplasm condensation, karyorrhexis, cytoplasm cleavage. Nevertheless, some ultrastructural peculiarities (atypical heterochromatin arrangement, appearance of nuclear envelope protrusions, absence of nucleolar structures) suggest that the apoptotic expression partially depends on the biological situation (type of organism and inducing factors) in which the programmed cell death takes place. The presence of histiocytic cells internalizing cell debris, of apoptotic and non-apototic derivation, may be correlated with the importance of recycling substances useful for embryo growth.

Phylogenetically distant intracellular symbionts in termites

Cockroaches are known to harbour intracellular bacteria in specialised cells (mycetocytes, or bacteriocytes) of the fat body. In termites, mycetocyte bacteria have been observed only in Mastotermes darwiniensis. These symbionts are thought to have originated from a bacterium that infected an ancestor common to cockroaches and termites. Thus, loss of the infection should have occurred during evolution in all termite lineages, with the exception of that leading to M. darwiniensis. One might suspect that traces of the ancient infection may be present in some termites, in the form of non-mycetocyte intracellular bacteria (e.g. a small number of bacteria within normal cells). Indeed, circumstantial evidence for the presence of intracellular bacteria in two termite species has been reported. However, no data are available on the actual distribution of these bacteria in termites, or on their relationships with the mycetocyte bacteria of cockroaches and M. darwiniensis. In this paper we report results indicating that non-mycetocyte intracellular bacteria are widespread in termites. These results were obtained by electron microscopy on representatives of nine termite species. In addition, sequence analysis of the 16S rRNA genes indicated that the non-mycetocyte bacteria of termites belong to the wolbachia group of the alpha-2 subclass of the proteobacteria. These latter bacteria are not related to the mycetocyte bacteria of cockroaches and M. darwiniensis, which belong to the blattabacterium group of the flavobacteria-bacteroides. PCR analyses with primers specific for wolbachia or blattabacterium provided further support for the identification of the observed non-mycetocyte bacteria as members of the wolbachia group.

Pulmonary microsporidiosis due to Encephalitozoon hellem in a patient with AIDS

The microsporidian Encephalitozoon hellem is being reported with increasing frequency in HIV-positive subjects, as an agent of disseminated microsporidiosis without involving the gastrointestinal tract. We describe a case of pulmonary microsporidiosis in a 27-year-old Italian man with AIDS who developed fever, cough, and dyspnea. A chest X-ray showed multiple bilateral pulmonary opacities and mediastinal lymph-node enlargement. Stained smears of bronchoalveolar lavage sediment showed oval structures consistent with microsporidian spores. Viral, bacterial and fungal cultures were repeatedly negative, whereas microsporidia were successfully cultured in human and bovine fibroblast cell lines. Analysis of electron micrographs indicated that the isolate belonged to the genus Encephalitozoon. Based on further immunological, biochemical and molecular studies it was characterized as E. hellem. Even though a temporary improvement with albendazole therapy was noticed, the patient deteriorated clinically and died of severe respiratory distress.

Microsporidian spore wall: ultrastructural findings on Encephalitozoon hellem exospore

A study of the spore wall of Encephalitozoon hellem was performed on thin sections, freeze-fracture, and deep-etched samples to obtain information on spore wall organization and composition. Our observations demonstrate that the spore wall is formed by an inner 30-35 nm electron-lucent endospore and an outer 25-30 nm electron-dense exospore. The exospore is a complex of three layers: an outer spiny layer, an electron-lucent intermediate lamina and an inner fibrous layer. Freeze-fracture and deep-etching techniques reveal that the intermediate lamina and the inner fibrous layer result from the different spatial disposition of the same 4-nm thick fibrils. In thin sections the endospore reveals a scattered electron-dense material that appears in the form of trabecular structures when analyzed in deep-etched samples. The presence of chitin in the exospore is discussed.

Restoration by piroxicam of liver glutathione levels decreased by acute ethanol intoxication

The effect of piroxicam, a nonsteroidal anti-inflammatory drug, on blood ethanol and on triacylglycerols, malondialdehyde and glutathione levels in liver of fed rats acutely intoxicated with ethanol was studied. As previously reported for fasted rats, piroxicam in fed rats decreases the concentration of ethanol in blood and inhibits the hepatic increase of triacylglycerols and malondialdehyde consequent to ethanol administration. In addition, the hepatic depletion of reduced and reduced plus oxidized glutathione observed 8 and 12h after gavage of ethanol was reversed when piroxicam was administered simultaneously with ethanol. The importance of the finding is discussed in light of the paramount participation of glutathione during the cellular oxidative stress.

[A family outbreak of acute hepatic fascioliasis]

The diagnosis of human fascioliasis was established in an 11 year old boy with prolonged fever by complement fixation and ELISA tests. Good clinical response followed the treatment with emetine. Four other family members were also affected with the disease and their treatment was equally effective. The origin of the infection was traced to the ingestion of infected watercress at a site 15 km away from Santiago.

[Multiple hydatid cysts and generalized cysticercosis]

A 64 year old male presented with parotid gland swelling and neck and pulmonary nodules. Contrast and scintigraphic studies ruled out a primary process of the gland. Other nodules were detected in the abdomen and upper limbs. Biopsy of one of these showed C cellulosae and a positive serologic test followed. On the other hand echographic findings support the diagnosis of lung hydatid disease.