Lactate causes changes in gonococci including increased lipopolysaccharide synthesis during short-term incubation in media containing glucose

Gonococci (strain BS4(agar)), emerging from lag-phase during 1-1.5 h incubation in a medium containing glucose (28 mM) and either 5 microM or 50 microM sodium lactate, show enhanced capacity for their lipopolysaccharide (LPS) to be sialylated by cytidine 5'-monophospho-N-acetyl neuraminic acid. The sialyltransferase content of the lactate-treated gonococci was not greater than that of control organisms and showed no differences in LPS components. However, the total LPS content of the lactate-treated gonococci was 10-20% higher than that of control organisms, so lactate enhancement may be due to more sialyl receptors becoming available due to an overall stimulation of LPS synthesis. The protein and pentose contents of the lactate-treated gonococci were also higher than those of controls, indicating stimulation of protein synthesis and ribosome production. Electron microscopy showed hair-like external appendages on control but not on lactate-treated gonococci. The above growth conditions are unnatural. However, when concentrations of glucose and lactate were adjusted to values akin to those occurring in vivo (glucose 5 mM alone and with either 1 mM or 10 mM lactate), and gonococcal multiplication occurred during the short incubation period (1-1.5 h), lactate again induced greater contents of LPS, protein and pentose. A high content of LPS, which will contribute to pathogenicity, should be a constant feature of gonococci growing in human urogenital tissues, where lactate is ever present with glucose.

Evidence for in vivo mitosis by granule-containing mast cells from canine mastocytomas

Mast cell accumulations are generally considered to arise almost exclusively from the recruitment of non-granulated, bone-marrow-derived, precursor cells, with the stem cell factor (SCF) reported to play a crucial role in the growth, development and maturation of granulated mast cells within specific tissue sites. In this study dog mastocytoma specimens have been examined by both immunohistochemical and ultrastructural techniques, to demonstrate that fully granulated mast cells are capable of mitotic activity. Observations showing the formation of mitotic spindles, chromosome separation and cytokinesis all support the concept that granulated mast cells are capable of proliferative activity. The ability of mature granulated mast cells to replicate provides an alternative process for local increases in mast cell numbers, at least in canine mast cell tumours. Such observations suggest the possibility that normal or neoplastic human mast cells, fully granulated, have the potential to proliferate in specific tissue sites.

Some ultrastructural data on Microsporidium ceylonensis, a cause of corneal microsporidiosis

Sections of corneal tissue infected with Microsporidium ceylonensis were restained or processed for electron microscopy. Confirmation was obtained that the parasite develops in macrophages and that spores are uninucleate. New information is provided that sporoblasts and spores develop synchronously within a membrane in the host cell, spores have an anisofilar polar tube of 6-10 wide coils and 2-3 narrow coils and details are given of the spore wall and internal organisation. The parasite was compared on the one hand with Encephalitozoon, which exhibits asynchronous intravacuolar development of merogonic and sporogonic stages and has spores with isofilar polar tubes and on the other hand with species reported from mammals, of which the sporogonic stages develop synchronously within sporophorous vesicles and the spores have anisofilar polar tubes. Even so, a generic emplacement could not be established. Attention is drawn to the similarities between M. ceylonensis and Nosema sp. described from the cornea of a woman in Botswana.

Differentiation of desquamative interstitial pneumonia (DIP) from pulmonary adenocarcinoma by immunocytochemistry

AIM

After a misdiagnosis of pulmonary adenocarcinoma as desquamative interstitial pneumonia (DIP), we investigated whether immunohistochemical markers could differentiate these conditions.

METHODS AND RESULTS

Three cases of DIP and one pulmonary adenocarcinoma masquerading as DIP were studied by light and electron microscopy. All cases were mucin-negative. The cases of DIP were CD68 positive but cytokeratin-negative. The adenocarcinoma was cytokeratin-positive (AE1/3 and CAM5.2), as well as showing some CD68-positive cells. Markers for carcinoma (CEA, Ber-EP4, and Leu M1) were negative in all cases. Ultrastructurally the adenocarcinoma appeared to be derived from Type II pneumocytes.

CONCLUSION

Before a diagnosis of DIP is made, cytokeratin markers should be used.

Cross-reaction of an anti-Cryptosporidium monoclonal antibody with sporocysts of Monocystis species

The non-specific cross-reaction of a fluorescently labelled anti-Cryptosporidium monoclonal antibody was observed microscopically when testing faecal specimens from small mammals. The reactive particles were identified as sporocysts of the Gregarine family Monocystidae, and indicate that considerable care should be taken so that false positives are not recorded.

Visceral leishmaniasis (Kala-azar) in two patients with HIV-1 infection: atypical features and response to therapy

Visceral leishmaniasis (VL) is a well recognized opportunistic infection in patients with HIV-1 infection, which may occasionally present with atypical features. We describe two patients with advanced HIV-1 infection (CD4<100/ mm3) in whom visceral leishmaniasis presented with atypical features, and their response to therapy. Atypical features of visceral leishmaniasis in the two infected patients include absence of fever, dissemination to the duodenal mucosa and to the skin as xanthoma-like lesions. Therapy and secondary prophylaxis remain unsatisfactory, and studies to evaluate combinations of amphotericin B and immunotherapy are needed.

Characterisation of 16 Campylobacter jejuni and C. coli typing bacteriophages

Taxonomic classification of bacteriophages specific for Campylobacter jejuni and C. coli has not been reported previously. A set of 16 virulent phages, distinguishable by their lytic spectra, has been used extensively for epidemiological typing of C. jejuni and C. coli at Preston Public Health Laboratory. These phages were investigated by electron microscopy, pulsed-field gel electrophoresis and restriction endonuclease analysis. All phages had icosahedral heads and long contractile tails. Accordingly, they were classified as members of the Myoviridae family. These phages could be subdivided into three groups according to genome size and head diameter: group I, two phages with head diameters of 140.6 and 143.8 nm and genome sizes of 320 kb; group II, five phages with average head diameters of 99 nm and average genome sizes of 184 kb; and group III, nine phages with average head sizes of 100 nm and average genome sizes of 138 kb. Phages NCTC12676 and NCTC12677 of group I had unusually large genomes of c. 320 kb which are two of the largest phage genomes to be described. Restriction endonuclease analysis demonstrated that DNA from the 16 phages was refractory to digestion by a number of restriction enzymes.

Information on alternative medicine: a collection management issue

Collection management of library materials about alternative medicine may be a growing problem for librarians because differing views exist regarding the acceptability of this information in a public forum. The purpose of the study reported was to investigate possible differences in the views of physicians, medical students, and librarians regarding the availability of information about alternative medicine for both medical students and the general public. Interviews were conducted with two representatives from each group, all of whom are affiliated with the Faculty of Medicine at The University of British Columbia or its library. The study was exploratory in nature, conducted in part to determine whether a larger research project in this area should be mounted. The data revealed considerable differences in opinion about alternative medicine: the librarians were more hesitant about the acceptability of radical or revolutionary materials, particularly those containing information that could result in direct harm to a patient. The physicians and medical students were more confident than the librarians that traditional medical treatment (and therefore information about it) should always be paramount.

Adenovirus-associated gastro-enteritis in the north-west of England: 1991-1994

Faeces, positive for adenoviruses by electron microscopy on initial examination at Manchester Public Health Laboratory (PHL) or Preston PHL during the period 1991-1994, were examined by an enzyme immunoassay which differentiated Ad40, Ad41 and non-AdF strains. Isolation and serotyping by neutralisation of non-AdF strains were attempted in PLC/PRF/5 cells. Of 452 specimens examined, 99 (22%) contained Ad40, 209 (46%) Ad41 and 144 (32%) non-AdF serotypes. From 1991 to 1993 the ratio of Ad40 to Ad41 was constant at approximately 1 to 1.6, but in 1994 it was almost 1 to 5. Non-AdF serotypes, of which Ad1 and Ad2 were the most common, accounted for 44% of specimens tested from 1991, but this dropped to 20% of those from 1994. An age/sex analysis showed that half the specimens examined were from infants under one year old, and that overall the male/female ratio was 3 to 2. The significance of these results is discussed, including the changing prevalence of Ad40 and Ad41, and the role of non-AdF serotypes in gastro-enteritis.

A New Microsporidium, Nosema cristatellae n. sp. in the Bryozoan Cristatella mucedo (Bryozoa, Phylactolaemata)

A microsporidian infecting cells of the body wall of the phylactolaemate bryozoan Cristatella mucedo is described. All stages of the parasite are diplokaryotic and lie in direct contact with the host cell cytoplasm. Sporogony is probably disporoblastic. Spores measure 7.5 x 5.1 &mgr;m and have 22-32 coils of the polar tube arranged in several rows and a bell-like polaroplast of compact membranes. The parasite is assigned to the genus Nosema as a new species, Nosema cristatellae. It is differentiated from the previously described parasites of Alcyonella (=Plumatella) fungosa (Bryozoa), named Myxosporidium bryozoides and Nosema bryozoides, by spore characters and tissue specificity. Although it was found in a different species of bryozoan, it is not known whether N. cristatellae is infective to P. fungosa. Copyright 1997 Academic Press. Copyright 1997 Academic Press

The prevalence of Enterocytozoon bieneusi in acquired immunodeficiency syndrome (AIDS) patients from the north west of England: 1992-1995

Microsporidia are increasingly being recognised as important enteric pathogens in patients with advanced human immunodeficiency virus (HIV) disease, i.e. acquired immunodeficiency syndrome (AIDS). The aims of this study were to investigate the frequency of detection of microsporidia associated with diarrhoea in patients with advanced HIV disease in the north west of England, and to determine the species involved and their prevalence. During the period from April 1992 to the end of December 1995, chronic diarrhoea in 88 patients in the late stage of HIV disease was investigated. Duodenal biopsies, duodenal aspirates or jejunal biopsies were received from 38 patients, and stool samples from 63 patients, as part of the routine investigation of possible causes of diarrhoea in these patients. Biopsies and aspirates were examined by thin-section electron microscopy (EM), and stool samples were examined by epi-fluorescence microscopy after staining with Calcofluor. Putative stool positives were confirmed by transmission electron microscopy. CD4-lymphocyte counts were available from all patients who provided samples. Nine out of 63 patients (14.3%) were found to be excreting microsporidial spores on stool examination. The species was confirmed as Enterocytozoon bieneusi. The mean CD4-lymphocyte count for this group was 37 x 10(6)/L (normal range 517-1677 x 10(6)/L). Three out of 38 biopsy specimens (7.9%) were also found to be infected with this microsporidian. The mean CD4-lymphocyte count for this group was 72 x 10(6)/L. Encephalitozoon intestinalis was not found in any samples examined. The prevalence of microsporidial infection in AIDS patients in the north west of England appears to be similar to that of patients in London, but less than that reported in studies from other developed countries.

Electron microscopy and serological features of a patient with Q fever prosthetic valve endocarditis

The clinical, serological and electron microscopic findings in a 47 year old woman with bioprosthetic valve coxiella endocarditis occurring 15 years after streptococcal endocarditis are described. The patient underwent valvular surgery a total of four times to control symptoms and remains well on medical therapy more than two years after her last operation.

Spindle cell and pleomorphic lipoma: an ultrastructural study

Spindle cell and pleomorphic lipoma are rare benign tumors of adipose tissue. Their histogenesis is poorly understood and pleomorphic lipoma has not previously been studied ultrastructurally. This study describes the morphology and ultrastructure of 6 cases of spindle cell and pleomorphic lipoma. Both spindle cell and pleomorphic lipomas showed similar ultrastructural features with an interrupted basal lamina, occasional non-membrane-bound lipid vacuoles and abundant rER. In all the cases mast cells were conspicuous and were intimately related to both spindle and pleomorphic cells. It is proposed that both the spindle and pleomorphic multinucleated cells that characterize these tumors are prelipoblastic mesenchymal cells. The possible significance of an interaction between these cells and mast cells is discussed.

Colonic tubular adenomas and intestinal spirochaetosis: an incompatible association

Two cases of tubulovillous adenoma and adjacent colonic mucosa were studied in which intestinal spirochaetosis had heavily colonized the non-neoplastic but not the neoplastic epithelium. Ultrastructural and histochemical studies were performed and we postulate that the reason for this disparity is the normal microvillous pattern of the non-neoplastic epithelium which facilitates colonization by the spirochaetes.

Leishmaniasis of the tongue treated with liposomal amphotericin B

A 66-year-old man, immunosuppressed because of a lymphoma and with severe ischaemic heart disease and proteinuria, presented with a swelling on the tongue due to leishmaniasis. His travel history suggested that he had acquired the infection in the Mediterranean area some years earlier. He was treated with liposomal amphotericin B for 21 days and made a good recovery despite a temporary deterioration in renal function. Oral lesions are a rare manifestation of Old World leishmaniasis. Liposomal amphotericin B is a novel treatment that may be well tolerated when there is concern about the toxicity of more established drugs.

Value of electron microscopy in diagnosis of renal disease

AIMS

To assess the role and value of electron microscopy in the diagnosis of renal disease.

METHODS

Retrospective evaluation of 88 renal biopsy specimens received for primary diagnosis by assessment of the contribution of electron microscopy to the final diagnosis in the knowledge of the light microscopy and immunofluorescence findings.

RESULTS

Electron microscopy had an important diagnostic role in 75% of cases and was essential or necessary for diagnosis in 25%. In 25% of cases electron microscopy was considered unhelpful in diagnosis.

CONCLUSION

Electron microscopy has an integral role in the diagnosis of renal disease, and tissue should be taken for electron microscopy in all cases if possible. In some selected cases once the light microscopy and immunofluorescence findings are known it may be possible to forego electron microscopic examination. Electron microscopy is particularly useful in the differential diagnosis of minimal change disease and the nephrotic syndrome.