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Biomedical subjects

R Soave

Publications and source records attributed to R Soave.

At least 37 records · Page 2Linked to original sources

Coccidian infections in AIDS. Toxoplasmosis, cryptosporidiosis, and isosporiasis.

Cryptosporidium sp. and Isospora belli are coccidian protozoan parasites that were long recognized as pathogens for many animal species. The medical community became acquainted with these organisms with the advent of AIDS. Both parasites are associated with persistent, debilitating enteritis and, in the case of Cryptosporidium, biliary tract involvement in patients with AIDS. For the immunocompetent host, infection with these two pathogens usually results in self-limited diarrhea. Cryptosporidiosis appears to occur more often than isosporiasis, but the true prevalence of both infections for various populations of humans is unknown. Clinically, cryptosporidiosis is indistinguishable from isosporiasis. Diagnosis is based on finding the acid-fast (red staining oocyst in stained fecal specimens). There is no known effective therapy for cryptosporidiosis, whereas patients with isosporiasis respond promptly to treatment with trimethoprim-sulfamethoxazole. Patients with AIDS and isosporiasis have a high relapse rate after achieving complete remission and therefore need to be maintained on suppressive therapy. Much more needs to be learned about these two fascinating, "newly recognized" parasites.

Acquired Immunodeficiency Syndrome↗

Asexual development of Cryptosporidium parvum within a differentiated human enterocyte cell line.

Unremitting diarrhea with malabsorption is associated with Cryptosporidium parvum infection of the small intestine in patients with AIDS. The lack of a well-defined in vitro model of C. parvum infection has severely hampered research into the biology of cryptosporidial invasion of the host epithelial cell and development of new pharmacologic and immunologic therapies. The adherent human intestinal epithelial cell line HT29 when grown in glucose-free medium develops morphologic and functional characteristics of the small intestine enterocyte and was used to develop an in vitro model of infection. Cryptosporidium oocysts obtained from AIDS patients were applied to a monolayer of cloned, differentiated HT29.74 cells. Cells were fixed and stained to estimate the degree of parasite infection. Schizonts were easily distinguished from the host cell by light microscopy. Twenty-four hours after 10(5) oocysts were added to approximately 10(6) HT29.74 cells, Cryptosporidium infection rates varied from 50 to 120 schizonts per 1,000 cells. Among 14 different experiments, the mean infection rate was 91 (+/- 18) schizonts per 1,000 cells. Electron microscopy at 6 and 24 h confirmed intracellular localization and development of schizonts. The morphologic features of the cryptosporidial schizonts within HT29.74 cells, which included the presence of a dense band and feeder layer, were identical to those described during cryptosporidial infection of human enterocytes in patients with AIDS. Fewer schizonts were observed at 5 days and beyond. Infection of differentiated HT29.74 cells (62 and 65 schizonts per 1,000 cells at 24 and 72 h, respectively) was over five times more efficient than infection of undifferentiated HT29.74 cells (9 and 5 schizonts per 1,000 cells at 24 and 72 h, respectively). In vitro infection of differentiated HT29.74 cells will allow a better understanding of the mechanisms by which C. parvum infects the small intestinal epithelium and will allow a systematic evaluation of new therapeutic agents.

Animals↗

Cryptosporidiosis and isosporiasis in patients with AIDS.

Cryptosporidium and Isospora belli are coccidian protozoan parasites that were long recognized as pathogens of animals. They were brought to the attention of the medical community by the advent of AIDS. These parasites are associated with persistent, devastating enteritis in patients with AIDS and self-limited diarrheal illness in the immunocompetent host. Cryptosporidiosis appears to be more common than isosporiasis in both patients with AIDS and those who are not immunosuppressed. Clinically, cryptosporidiosis is indistinguishable from isosporiasis. Watery, noninflammatory diarrhea, abdominal cramping pain, and weight loss are the characteristic symptoms. Diagnosis is made by identification of the acid-fast organisms in stained fecal specimens. There is no known effective therapy for cryptosporidiosis, whereas patients with isosporiasis respond promptly to treatment with trimethoprim-sulfamethoxazole. Patients with AIDS and isosporiasis have a high frequency of recurrent infection and therefore should be maintained on suppressive therapy. Much more needs to be learned about these two fascinating and unique parasites to be able to intervene successfully in the management of infected patients with AIDS.

Acquired Immunodeficiency Syndrome↗

Enzyme immunoassay detection of immunoglobulin M and G antibodies to Cryptosporidium in immunocompetent and immunocompromised persons.

Cryptosporidium is a parasite of the human gastrointestinal tract and has a worldwide distribution. We developed a sensitive and reproducible enzyme immunoassay for detection of serum IgG or IgM to Cryptosporidium. For IgG, 13 of 15 patients with cryptosporidiosis and 26 of 26 patients with cryptosporidiosis and AIDS were positive, whereas 57 of 60 presumably uninfected individuals were negative. All three IgG-positive presumably uninfected individuals had been potentially exposed. Sensitivity and specificity of this assay was 95%. Patients without AIDS showed an early rise and fall of IgM and later elevation of IgG; some patients with AIDS produced IgM, and all produced IgG. Sera from 9 (20.9%) of 44 Ecuadorian children with diarrhea were positive for both IgM and IgG antibodies; 106 sera from persons with other parasitic illnesses showed a normal distribution for IgG antibody. These ELISA data show that patients without and with AIDS have serum antibody response to Cryptosporidium and suggest that exposure to or infection with Cryptosporidium is common.

Acquired Immunodeficiency Syndrome↗

Comparison of ceforanide and cephalothin prophylaxis in patients undergoing total joint arthroplasty.

One hundred one patients undergoing total hip and knee arthroplasty were randomly assigned to receive either two 1 gm doses of ceforanide or five doses of cephalothin perioperatively. Simultaneous plasma and cancellous bone specimens were obtained intraoperatively and assayed for antibiotic concentration. Ceforanide plasma and bone levels remained sustained over six hours. Cephalothin plasma and bone levels obtained three to four hours post administration were 91% lower than levels obtained one hour post-dose. Patients were examined for infection for up to 18 months following surgery. None of the patients developed an infected implant. The sustained plasma and bone levels achieved with ceforanide obviate the need for intraoperative dosing necessary with other agents.

Adult↗

Biliary tract obstruction in the acquired immunodeficiency syndrome.

Three patients with the acquired immunodeficiency syndrome had biliary obstruction resulting from benign strictures of the biliary tract. Stenosis of the distal common bile duct with differing degrees of irregularity of the smaller intrahepatic and extrahepatic ducts was seen in association with either cryptosporidial or cytomegaloviral infection of the biliary tree. We review cytomegaloviral and cryptosporidial infections of the biliary system, as well as possible relationships with idiopathic primary sclerosing cholangitis. Stenotic biliary tract disease appears to be yet another complication of the acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗

Cryptosporidiosis. Traveler's diarrhea in two families.

Intestinal cryptosporidiosis was diagnosed in three infants (aged 6 to 21 months), one child (aged 3 years), and two adult members of two families after their return from travel to the African continent. Examination of stools from all patients revealed acid-fast cryptosporidial oocysts on direct fecal smears stained by the modified cold Kinyoun technique. Five of the six were symptomatic with watery diarrhea, anorexia, and abdominal pain. Elevated anticryptosporidial titers were detected in five patients, two of whom were asymptomatic. Cryptosporidiosis should be included in the differential diagnosis of traveler's diarrhea.

Adult↗

Cryptosporidiosis in homosexual men.

Between April 1982 and June 1983, cryptosporidiosis was diagnosed in six homosexual men. Four patients with the acquired immunodeficiency syndrome had lymphopenia, cutaneous anergy, and profoundly impaired cellular immunity; their cryptosporidiosis was severe, unremitting, and refractory to all therapy. Two patients without other opportunistic infections or Kaposi's sarcoma had moderately impaired cellular immunity but not lymphopenia or anergy; their enteric illness was self-limited. Cryptosporidium recently had been recognized as a human pathogen that is transmitted through fecal-oral contamination. The severity of human cryptosporidiosis appears to be determined primarily by immunocompetence of the patient. These six homosexual men, with different degrees of immunologic impairment, had two clinically divergent forms of cryptosporidiosis. Their cases raise questions about human transmission of Cryptosporidium and the prognostic significance of this disease in patients who are at high risk for developing the acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗

Three-step stool examination for cryptosporidiosis in 10 homosexual men with protracted watery diarrhea.

Cryptosporidiosis, a zoonosis caused by Cryptosporidium species, is a newly recognized coccidial protozoan infection causing severe protracted watery diarrhea in humans. In August 1981, the first case of cryptosporidiosis in a homosexual man with acquired immune deficiency syndrome (AIDS) was reported; diagnosis was determined by intestinal biopsy. It is necessary to adopt a simple laboratory diagnostic procedure to screen large numbers of suspected cases. A three-step stool examination was developed to demonstrate Cryptosporidium oocysts and the diagnostic and infective stages of the infection in 10 homosexual men with AIDS. This is a less invasive, less costly, and more sensitive test than intestinal biopsy and has been designed to prevent confusion caused by yeast cells that are frequently present in stool, leading to a false diagnosis. The examination consists of preliminary differential determination by iodine wet mount, definitive identification by modified Kinyoun acid-fast staining, and a more effective method of concentrating oocysts, by Sheather's sugar cover-slip flotation method.

Acquired Immunodeficiency Syndrome↗

Appendicitis with perforation: a reminder to internists.

Over a two-year period, four adults with appendicitis were admitted to the medical service with manifestations sufficiently atypical to obscure the correct diagnosis. Perforation of the appendix was found in each, and abscess formation occurred in two cases. One patient died. The experience with these cases reemphasizes the protean manifestations of complicated appendicitis.

Abscess↗