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Biomedical subjects

D H Connor

Publications and source records attributed to D H Connor.

At least 73 records · Page 4Linked to original sources
PubMed1978

Onchocercal lymphadenitis: Clinicopathologic study of 34 patients.

Clinicopathological studies on lymph nodes of 32 Africans with onchocerciasis--some complicated by hanging groin and elephantiasis of the genitalia--revealed atrophic lymphoid tissue, lymphoedema, chronic inflammation and fibrosis. We identified microfilariae of Onchocerca volvulus in nodes of 24 of 32 Africans (75%). There microfilariae were most numerous in the capsule and in the fibrous tissue of the medulla, but smaller numbers were also found within lymphoid tissue, in dilated lymphatics and in blood vessels. We believe that in Africians, antigens released from microfilariae of O. volvulus lead to the deposition of immune complex in tissues, which in turn causes inflammation and fibrosis and eventually obstructive lymphadenitis. This causes hanging groin and, possibly, also elephantiasis. A distinctive pattern of perivascular fibrosis contains "fibrinoid material" that we interpret as immune complexes involving microfilarial antigens. In contrast, nodes from two Yemenites with severe onchocercal dermatitis of the lower limbs (sowda) had hyperplastic follicles, minimal fibrosis and no microfilariae.

Adolescent↗
PubMed1977

Onchocerciasis: invasion of deep organs by Onchocerca volvulus.

Autopsies of two patients with onchocerciasis in the Republic of Zaïre are reported. In one patient elephantiasis who died following diethylcarbamazine therapy there were large numbers of microfilariae of Onchocerca volvulus in the kidney, liver, pancreas, and lung. In the second patient, who also had leprosy and hyperinfection strongyloidiasis, we found an encapsulated adult O. volvulus in the wall of the thoracic aorta.

Aorta, Thoracic↗
PubMed1976

Autopsy analysis of disease frequency in Kinshasa, Republic of Zaire.

Between July 1973 and December 1974, 304 autopsies were done at Hopital Mama Yemo, Kinshasa, Republic of Zaire. The causes of death and sudden death were tabulated and analyzed. The frequency of various diseases and groups of diseases among all the individuals and a large subset of individuals who died traumatically are tabulated and discussed. The present report is the most quantitative, albeit only, current estimate of mortality and prevalence of diseases in Zaire.

Adolescent↗
PubMed1976

Onchocercal dermatitis: ultrastructural studies of microfilariae and host tissues, before and after treatment with diethylcarbamazine (Hetrazan).

Specimens of skin from four Cameroon patients with severe onchocercal dermatitis, before and after treatment with diethylcarbamazine (DEC), were studied by light and electron microscopy. Microfilariae of Onchocerca volvulus have ultrastructural features resembling those of microfilariae of other genera. Between the surface layer of the cuticle and the trilaminate membrane, there is an electrolucent zone which is much wider in degenerating microfilariae than in intact microfilariae. Widening of the zone may result from DEC-induced release of component(s) of the cuticle, possibly collagen or mucopolysaccharide. Between the cuticle and dermal collagen there are granular deposits which might be immune complexes involving the collagenous component of cuticle. Others have shown that DEC does not kill microfilariae in vitro. Treatment with DEC presumably "unmasks" microfilariae in the skin so that they are recognized as foreign bodies and are destroyed by the host's defenses. Histiocytes and eosinophils are seen in close proximity to degenerating microfilariae. Enzymes from histiocytes and eosinophils might readily penetrate the cuticle altered by DEC treatment, and digest various components within the microfilariae. Alternatively, the widening of the electrolucent zone might result directly from the action of leucocytic or histiocytic enzymes, after the microfilaria has been killed by other mechanisms.

Adult↗
PubMed1976

Disseminated parasitosis in an immunosuppressed patient. Possibly a mutated sparganum.

The autopsy of a man who died of Hodgkin disease revealed that a peculiar metazoan parasite had proliferated and disseminated throughout his body. The parasite could not be identified; however, electron microscopical studies revealed that it had the structure of a flatworm. This, together with its shape and structure, convinced us that the parasite was an aberrant sparganum manifesting uncontrolled proliferation and dissemination.

Blood Vessels↗
PubMed1975

Fatal infections in protein-calorie malnourished children with thymolymphatic atrophy.

The clinicopathological features of 25 children who died with protein-calorie malnutrition were studied. All but four subjects were found at necropsy to have nutritional thymectomy and all but 3 died of infectious diseases. The infectious agents were chiefly intracellular micro-organisms including miliary tuberculosis, Herpes simplex, varicella, measles, Pneumocystis carinii, and Plasmodium falciparum. Staphylococcal infections, salmonellosis, shigellosis, strongyloidiasis, and hookworm were other significant infectious agents. Nutritionally acquired defective immunity, especially cell-mediated immunity, probably permitted these infectious agents to multiply and to disseminate widely.

Atrophy↗
PubMed1975

Dipetalonema streptocerca (Macfie and Corson, 1922): description of the adult female.

Morphologic features of the adult female Dipetalonema streptocerca and microfilariae are described and illustrated from serial paraffin sections of biopsied skin from eight Africans. Characteristic features include a maximum diameter of 85 microns, a thin, smooth cuticle, and uteri that fill the body cavity. D. streptocerca is briefly compared to Onchocerca volvulus.

Animals↗
PubMed1974

Cytotoxic activity of Mycobacterium ulcerans.

Although Mycobacterium ulcerans elicits extensive necrosis of human skin and subcutaneous tissue, the specific cause of the necrosis has never been elucidated. In an attempt to define a toxic substance, 18 strains of M. ulcerans were inoculated into mice, and the progress of each infection was observed and compared with infections of other mycobacteria, including M. cheloni, M. marinum, and M. bovis. Culture filtrates and viable organisms of each of these mycobacteria were inoculated onto tissue culture cells. Inoculation of mouse footpads with M. ulcerans resulted in progressive infections, leading to ulceration and eventual death. Strains of M. cheloni, M. marinum, and M. bovis did not produce progressive infections in the mice. Culture filtrates of M. ulcerans produced severe cytopathogenic effects on tissue cells, but washed, viable organisms of the same strains had no cytopathogenic effect. Culture filtrates and viable organisms of M. cheloni, M. marinum, and M. bovis did not produce a cytopathogenic effect on the tissue cells. Viable organisms of selected strains of M. ulcerans and the culture filtrates of the same strains were inoculated into guinea pig skin. The culture filtrates and the viable organisms both caused focal necrosis and focal inflammation, changes that resemble those in the naturally occurring infection in man. Preliminary purification of the culture filtrate by ultrafiltration indicates that the toxic fraction has a molecular weight of approximately 100,000, and temperature studies indicate that the toxic fraction is heat labile.

Animals↗
PubMed1974

Human Mycobacterium ulcerans infections developing at sites of trauma to skin.

In Zaire, we studied 180 patients with Mycobacterium ulcerans infections and found 14 with a history of antecedent trauma at the site of the lesion (e.g., gunshot and land mine injuries, penetrating wood splinters, and scorpion stings). Two patients developed lesions following hypodermic injections. We believe that trauma is an important mode of transmitting M. ulcerans infections, or of introducing the etiologic agent into the dermis of subcutaneous tissue from superficially contaminated skin.

Adipose Tissue↗