Phylogeography and recent emergence of the Old World screwworm fly, Chrysomya bezziana, based on mitochondrial and nuclear gene sequences.

A previous study had identified an African and an Asian race of the Old World screwworm fly, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), based on the 3' terminal 279 basepairs (bp) of the mitochondrial cytochrome b gene. The current study improved the phylogeographic resolution of cytochrome b for this species by characterizing more of the gene (the 3' terminal 715 bp) and by sampling more geographical populations, including Oman, Iran, Hong Kong and the Indonesian islands of Sulawesi and East Sumba. Strong support was found for recognizing an African race, but not for a monophyletic Asian race. The cladistic and genealogical relationships among the Asian populations were complex. There was sufficient genetic homogeneity throughout separate regions (mainland Asia and each Indonesian island) to suggest that there are no reproductive barriers within each region that might necessitate the production of more than one strain for control by the sterile insect technique (SIT). Primers were designed for the amplification by polymerase chain reaction of two nuclear loci, the highly conserved elongation factor-1alphagene and the less conserved white gene, and the preliminary results indicated that these genes showed the same pattern of small-scale regional variation as cytochrome b. The cytochrome b haplotypes are useful markers for identifying the geographical origins of any emerging infestations of the species: the absence of Indonesian and African haplotypes in the Middle East demonstrates that the large-scale transport of livestock is not spreading Old World screwworm.

A case of eruptive milia.

A 68-year-old woman presented with a 10-year history of multiple milia on her scalp. Spontaneous eruptive milia are uncommon and the term describes cases that are more extensive in number and distribution than would be expected in primary milia.

Seasonality of Old World screwworm myiasis in the Mesopotamia valley in Iraq.

Following the first recorded introduction of the Old World screwworm fly (OWS), Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), into the Mesopotamia valley in Iraq in September 1996, cases of livestock myiasis caused by OWS developed a distinctly seasonal pattern. The annual cycle of clinical OWS cases is explained here on the basis of environmental variables that affect the different life-cycle stages of C. bezziana. This analysis suggests that low temperatures restricted pupal development during the winter, whereas the dispersal of adult flies was constrained by hot/dry summer conditions. A restricted number of OWS foci persisted throughout the year. In these foci, pupal development was fastest during the autumn months. In autumn, rapid multiplication, lasting several OWS generations, allowed subsequent adult fly dispersal across the valley floor during the winter. Hence, the monthly incidence of clinical OWS cases in livestock peaked during December-January and was lowest during July-August. In addition to temperature and humidity, vegetation cover played a role in OWS distribution. Hence the majority of OWS cases were clustered in the medium density type of vegetation [normalized difference vegetation index (NDVI) values of 0.2-0.4] along the main watercourses in the marshy Mesopotamia valley. Although sheep were the host most commonly infested by C. bezziana, local sheep density was not found to be a major factor in disease spread. Satellite imagery and the application of Geographical Information System (GIS) tools were found to be valuable in understanding the distribution of OWS in relation to vegetation and watercourses. The presence of screwworm in Iraq, at the perimeter of the intercontinental OWS distribution, may give rise to major seasonal flare-ups.

Testicular granulocytic sarcoma, a source of diagnostic confusion.

We report a case of granulocytic sarcoma of the testis without hematologic manifestations. The patient was disease free 7 years after the initial presentation. The initial pathology interpretation favored a diagnosis of high-grade non-Hodgkin's lymphoma but additional histologic staining confirmed the diagnosis of granulocytic sarcoma. Only 2 cases of testicular granulocytic sarcoma without an associated hematologic disorder have been described. To our knowledge, this is the third reported case. The diagnosis of this rare tumor is difficult and should be in the differential diagnosis when non-Hodgkin's lymphoma is considered.

Macrophages, microglial cells, and HLA-DR antigens in fetal and infant brain.

Immunohistochemical reactions for macrophages, microglia, and HLA-DR antigens were tested on frozen sections of necropsy brain tissue from 20 fetuses and infants ranging in age from 18 weeks' gestation to 8 months post term. No primary central nervous system disease was present but there were four cases of sudden infant death syndrome (SIDS). Macrophages were detected in all the samples studied and were located in the germinal matrix zone, in perivascular spaces throughout the brain, and in the leptomeninges and subependymal layer. Well differentiated microglia were present in all cases examined after 35 weeks' gestation and less well ramified forms were seen at earlier stages of gestation. HLA-DR antigens were detected on a small number of macrophages, chiefly in a perivascular location, in all but three cases. The fewest reactive cells and the weakest reactions occurred in the youngest fetuses. One case of SIDS showed increased foci of microglia in perivascular white matter: this case and one other case of SIDS were the only cases with well ramified microglia that expressed HLA-DR antigens. These findings may be relevant to an understanding of local immune responses in fetal brain infections, including human immunodeficiency virus infection.

Mononuclear cell infiltrate and HLA-Dr expression in intra- and extradural secondary carcinomas.

Frozen sections from 30 secondary carcinomas (22 intra- and 8 extradural) were reacted with a panel of monoclonal antibodies to macrophages, lymphocytes, NK cells and HLA-Dr invariant chain. A moderate number of macrophages was demonstrated in 91% of tumours. CD 8 and CD 4 lymphocytes were detected in smaller numbers in 68% and 28% of tumours respectively. B lymphocytes were present in only one tumour and NK cells were absent. There was no significant difference between the mononuclear cell infiltrate in the intra- and extradural tumours and in respect to the histological tumour type. HLA-Dr antigen was expressed by macrophages in most cases and by tumour cells in 5/22 (22%) (4 adeno and 1 anaplastic carcinoma; of which one adenocarcinoma was extradural and the remaining intradural). The results may represent evidence for a degree of cellular immune response to secondary carcinomas which is independent of the intra- or extradural location of the tumour.

Mononuclear cell infiltrate and HLA-Dr expression in 28 pituitary adenomas.

Frozen sections from 28 pituitary adenomas were reached with a panel of monoclonal antibodies to macrophages, lymphocytes and HLA-Dr invariant chain. A low number of macrophages were demonstrated in all tumors, mainly perivascular. CD8 and CD4 lymphocytes were detected in even smaller numbers in 80% and 14% of tumors respectively. B lymphocytes were present in only 1 case. An occasional NK cell was present in 1/13 cases studied. HLA-Dr antigen was expressed by macrophages in all cases and by tumor cells in 2 growth hormone-producing adenomas/19 adenomas. These findings may represent evidence for a low degree of cellular immune response to pituitary adenomas.

Pleural mesothelioma of connective tissue type, localized fibrous tumour of the pleura, and reactive submesothelial hyperplasia. An immunohistochemical comparison.

Ten diffuse pleural mesotheliomas of connective tissue type have been compared with 14 examples of pleural granulation tissue and 7 localized fibrous tumours of the pleura, using immunohistochemistry to identify cytokeratins of low and high molecular weight and vimentin. Low molecular weight cytokeratin and vimentin were both detected in 8 of the 10 mesotheliomas and in 12 of the 14 reactive lesions. High molecular weight cytokeratin was rarely detected in either lesion. The seven localized fibrous tumours of the pleura were all positive for vimentin and negative for both cytokeratins. These findings support an origin of connective tissue type mesotheliomas from multipotential submesothelial spindle cells and of localized fibrous tumours of the pleura from either conventional fibroblasts or resting submesothelial spindle cells. Antibodies to cytokeratin help distinguish these two neoplasms but provide no assistance in the more difficult diagnostic problem of distinguishing mesotheliomas of connective tissue type from pleural reactions characterized by abundant granulation tissue.

Malignant transformation in endometriosis of the urinary bladder.

A case of primary intravesical endometrioid carcinoma is described, together with a review of the literature. This represents the fourth reported case of malignant transformation in vesical endometriosis.

Angiotropic large cell lymphoma (angioendotheliomatosis) presenting with protein-losing enteropathy.

A 73 year old female presented with progressive hypoproteinaemic oedema which was resistant to treatment. The cause was not established until post-mortem, when it was found that she had angiotropic large cell lymphoma involving the vessels of the large intestine with mucosal ulceration. To our knowledge, this is the first report of angiotropic large cell lymphoma, which usually presents with neurological and skin involvement, presenting with protein-losing enteropathy.