Cryptosporidium parvum infection in suckling rats: impairment of mucosal permeability and Na(+)-glucose cotransport

Na(+)-glucose transport and transepithelial permeability were investigated during symptomatic acute cryptosporidiosis in newborn rats. The infection resulted in a significant (P < 0.01) decrease in the ileal short-circuit current and a nonsignificant fall in the transepithelial potential difference and conductance. In glucose-stimulated conditions, the rise in ileal short-circuit current and transepithelial permeability were significantly lower in Cryptosporidium parvum-infected rats than in controls (delta Isc = 3.24 +/- 1.21 microA.cm-2 vs delta Isc = 5.09 +/- 2.23 microA.cm-2 in infected and control animals, respectively; P < 0.001; delta PD = -0.35 +/- 0.13 mV vs delta PD = -0.44 +/- 0.14 mV for infected and control animals, respectively; P < 0.01). Electrical parameters were not affected by addition of the cyclooxygenase inhibitor indomethacin in either Cryptosporidium-infected newborn rats or controls. Horseradish peroxidase and mannitol flux studies demonstrated a significant decrease (P < 0.05) in transepithelial molecular permeability in infected enterocyte rats, HRP flux = 380, range 68-5570 ng.cm-2, and mannitol flux = 1.06, range, 0.34-1.44%.cm-2.min-1, compared with controls rats, HRP flux = 4446 range, 1121-124,363 ng.cm-2, and mannitol flux = 1.99, range, 0.57-5.09%.cm-2.min-1; P < 0.05. These effects could originate from C. parvum-induced alteration of intracellular trafficking of pinocytosis vesicles and therefore account for the decrease in permeability to solute and macromolecules, together with impaired transcellular nutrient transport, in suckling rats.

Effects of lamivudine on replication of hepatitis B virus in HIV-infected men

BACKGROUND

Therapy for hepatitis B virus (HBV) infection is still unsatisfactory, particularly in patients who are co-infected with the human immunodeficiency virus (HIV). Lamivudine, a retroviral inhibitor, has been shown to have activity against HBV replication in vitro, in animal models, and in studies of immunocompetent persons.

OBJECTIVE

To assess the efficacy of lamivudine in inhibiting HBV replication during a 12-month period in patients with both HBV and HIV infection.

DESIGN

Prospective, open study.

SETTING

University hospital.

PATIENTS

40 consecutive patients (39 men and 1 woman) infected with both HIV and HBV. All had progressive HIV disease; were refractory to or unable to tolerate therapies other than lamivudine; and received lamlvudine, 600 mg/d or 600 mg/d followed by 300 mg/d, as therapy for HIV disease.

MEASUREMENTS

Serum concentrations of HBV DNA were assessed every 2 months by using molecular hybridization. Polymerase chain reaction (PCR) for HBV DNA was done at baseline and was done at months 2, 6, and 12 only if the HBV DNA concentration was less than 5 pg/mL.

RESULTS

Two groups were retrospectively identified at baseline: patients with high HBV replication (serum HBV DNA concentrations > 5 pg/mL) (n = 30) and patients with low HBV replication (serum HBV DNA concentrations < 5 pg/mL) (n = 10). After 12 months of treatment, 26 of 27 patients (96.3% [95% Cl, 81% to 99.9%]) who had had high HBV replication at baseline had serum HBV DNA concentrations less than 5 pg/mL. However, PCR could still detect HBV DNA in serum in 11.5% (Cl, 2% to 30%) of these patients. Among patients who had had low HBV replication at baseline, the results of PCR for serum HBV DNA became negative in the 6 patients who had had a positive result on PCR at baseline. No serious adverse events occurred during treatment.

CONCLUSION

Although this study was not a randomized, blinded trial, it suggests that lamivudine is active against.

Kinetics of mucosal ileal gamma-interferon response during cryptosporidiosis in immunocompetent neonatal mice

The kinetics of serum and ileal interferon-gamma (IFN-gamma) content were determined during recovery from cryptosporidiosis in NMRI suckling mice. A total of 60 mice aged 4 days were inoculated by intragastric gavage with 10(4) cryptosporidia (n = 30) or phosphate-buffered saline (n = 30). Six animals per group were killed on days 0, 3, 6, 9 and 13 postinoculation. Blood samples and ileum were collected. Experimental infection was followed by a rise in parasite load in the ileum starting on day 3 postinfection, which peaked at day 6 postinoculation. Ileal IFN-gamma levels increased rapidly in parasitized mice from day 3 to day 6, then fell rapidly. These levels were significantly higher than the control values (day 3 P < 0.05, days 6 and 9 P < 0.001). IFN-gamma secretion began before parasite excretion, but the curves of these two parameters correlated positively. Recovery from cryptosporidiosis in immunocompetent neonatal mice is thus associated with an early and marked increase in ileal IFN-gamma content.

Treatment of AIDS-associated gastrointestinal cytomegalovirus infection with foscarnet and ganciclovir: a randomized comparison

Patients with symptomatic gastrointestinal disease due to cytomegalovirus (CMV) were randomized to receive open-label ganciclovir (22) or foscarnet (26). Patients were stratified by disease site and concurrent gut infection. Response was assessed by a visual analogue score of symptoms, endoscopic appearances, histologic inflammation, and numbers of CMV inclusions. In each treatment group, 73% had a complete or good clinical response; 83% of foscarnet-treated and 85% of ganciclovir-treated patients showed response by endoscopy, and inclusion bodies disappeared from follow-up biopsies in 73% of these. Most patients (35) developed further evidence of CMV disease during follow-up. The time to progression was not significantly different between recipients (16 weeks) and nonrecipients (13 weeks) of maintenance therapy, although patients were not randomized to receive maintenance or not. Survival in both treatment groups was < 40 weeks and was unaffected by maintenance treatment. Both ganciclovir and foscarnet are effective first-line treatments for gastrointestinal (GI) CMV infection. Maintenance therapy does not prevent progression of disease.

Flumazenil therapy for hepatic encephalopathy in cirrhotic patients: a double-blind pragmatic randomized, placebo study

OBJECTIVE

To evaluate the effects of flumazenil on hepatic encephalopathy in patients with cirrhosis.

DESIGN

Double-blind randomized study.

SETTING

Liver intensive care unit over a 2-year period.

PATIENTS

Fourteen patients with cirrhosis (median age 54 years, range 41-73 years), comprising 10 men and four women enrolled during 18 episodes of hepatic encephalopathy.

METHODS

Placebo or flumazenil (1 mg at 0.1 mg/min infusion rate) was infused in coded vials. The patients' hepatic encephalopathy was graded clinically and by electroencephalography (EEG).

RESULTS

In eight episodes of hepatic encephalopathy the placebo was infused first and no improvement occurred (0%). During 12 episodes of hepatic encephalopathy, flumazenil was administered and the EEG recording improved within 7 min (range 4-47 min; 12 out of 18 cases; 66 versus 0% for flumazenil versus placebo, respectively; P < 0.01); a modest clinical improvement in hepatic encephalopathy was observed within 83 min (range 30-340 min). The amount of flumazenil infused averaged 0.7 mg (range 0.4-1 mg).

CONCLUSIONS

The infusion of 0.4-1 mg flumazenil results in a modest but rapid improvement in the EEG grading of hepatic encephalopathy and to a moderate but delayed improvement in the clinical grade of hepatic encephalopathy.

A high-yield outbred suckling mouse model of cryptosporidiosis

Outbred suckling mice (NMRI strain) were used as hosts. They were initially inoculated with oocysts of human origin, and subsequently with parasites recovered from the mouse ileal mucosa. Cryptosporidia were counted in an aliquot of whole-ileum homogenate. Parasite load was expressed as cryptosporidia per centimeter of ileum. Serial passage of C. parvum in NMRI mouse litters led to a gradual amplification of parasite burden relative to animals initially inoculated with the human isolate.

Inefficacy of intestinal secretory immune response to Cryptosporidium in acquired immunodeficiency syndrome

BACKGROUND/AIMS

An alteration of the secretory immune response has been forwarded to explain frequent and chronic mucosal infections in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to explore the intestinal immunoglobulin (Ig) secretions in patients with AIDS and their relationships to cryptosporidiosis.

METHODS

Patients with AIDS and enteric cryptosporidiosis (n = 12), other enteric infections (n = 10), and no identifiable enteric pathogen (n = 10) and human immunodeficiency virus-seronegative controls (n = 18) were studied. The number of intestinal IgA and IgM plasma cells of the duodenal lamina propria mucosa and total and anti-Cryptosporidium IgA, IgM, and IgG were measured in serum and feces.

RESULTS

Although not significantly increased, the number of IgA and IgM plasma cells was greater in patients with AIDS (n = 20) than in controls (n = 5). In feces, total IgA outputs and specific anti-Cryptosporidium IgA levels were significantly higher in patients with AIDS and cryptosporidiosis than in the two other groups of patients with AIDS (P < 0.05 and P < 0.01, respectively) and controls (P < 0.001 and P < 0.01, respectively). Total fecal IgM output and specific anti-Cryptosporidium IgM coproantibodies were increased only in the Cryptosporidium-infected patients relative to the controls (P < 0.05).

CONCLUSIONS

Despite the development of pathogen-specific mucosal antibody responses, patients with AIDS and cryptosporidiosis fail to clear the parasite.

Association of lipid accumulation in small intestinal mucosa with decreased serum triglyceride and cholesterol levels in AIDS

Lipid accumulation has been described in the duodenal lamina propria of human immunodeficiency virus (HIV)-infected patients with diarrhea and malabsorption. Using light and electron microscopy, we studied duodenal biopsies obtained from 54 consecutive HIV-infected patients by means of upper gastrointestinal endoscopy after an overnight fast. The presence of diarrhea and weight loss were recorded, and all the patients had standard stool study for ova, parasites, and bacteria. Serum levels of albumin, triglycerides, and cholesterol were obtained within one week of the endoscopy. Fecal fat and fecal alpha 1-antitrypsin clearance were measured in 11 patients. Lipid accumulation was observed in nine patients (16.6%). Fat droplets were seen in enterocytes, in their basolateral membrane spaces, and in the lamina propria. The mean serum levels of triglycerides (1.85 +/- 0.20 mmol/liter) and cholesterol (2.81 +/- 0.30 mmol/liter) were significantly lower in the patients with enteric steatosis than in patients without this anomaly (respectively, 3.38 +/- 0.39 and 3.97 +/- 0.18 mmol/liter, P < 0.001 P < 0.01). The mean amount of fecal fat in the three patients with lipid accumulation (16 +/- 1.60 g/24 hr) was significantly larger than in the eight patients without lipid accumulation (4.50 +/- 0.62 g/24 hr, P < 0.01). These findings suggest that fat malabsorption in HIV-infected individuals is due to a blockage of transport through the duodenal mucosa. The frequency of diarrhea, weight loss, or identified enteric pathogens did not differ significantly between patients with and without enteric steatosis. Both the etiology and the pathophysiology of these alterations remain to be documented.

Hypnotic relaxation: a new sedative tool for colonoscopy?

Sedation is often justified in patients requiring colonoscopy. We investigated the potential usefulness of hypnotic relaxation in 13 women and 11 men (median age, 43 years; range, 22-67) for whom other forms of anesthesia were not available. Hypnotic relaxation resulted in moderate or deep sedation in 12 patients (nine women; p < 0.05). In the patients in whom hypnosis was successful, pain was less intense than in patients in whom hypnosis was unsuccessful (p < 0.001). In addition, all colonoscopies were completed in the successful group, versus 50% in the unsuccessful group (p < 0.05). The patients in the successful group all agreed to another examination under the same conditions, whereas only 2% in the unsuccessful group agreed (p < 0.001). Our study suggests that, in a subgroup of hypnotizable patients, hypnotic relaxation may be a safe alternative to drug sedation and merits further study.

AIDS-related cholangiopathy. Critical analysis of a prospective series of 26 patients

Several types of biliary tract abnormality of undetermined origin have been described among AIDS patients. The aims of this study are: (1) to evaluate whether biliary tree involvement is in fact one or several homogeneous morphological entities, (2) to specify the role of CMV or Cryptosporidium sp. infection, and (3) to evaluate the possible efficacy of treatment. Since ultrasound had revealed abnormality in the biliary tree, 26 consecutive AIDS patients underwent cholangiography. Cholangiograms enabled us to distinguish between two types of biliary tract involvement: (1) gradual and regular stenosis of the terminal portion of the common bile duct associated with dilation but without irregularity of the intrahepatic biliary ducts was present in 27% of our cases, and (2) distal stenosis of the extrahepatic biliary ducts combined with diffuse irregularity of the caliber of the intrahepatic bile ducts was present in 73% of our cases. Concomitant infection by CMV or Cryptosporidium sp. was significantly more frequent when intrahepatic duct irregularities were present (94%) than when absent (14%, P < 0.001). Anti-CMV treatment and sphincterotomy were unsuccessful in treating anomalies of the intrahepatic biliary tract. Conversely, sphincterotomy caused rapid and lasting disappearance of pain in all our patients. In conclusion, biliary tract involvement in AIDS patients is of two types. CMV infection and infection by Cryptosporidium sp. are most frequent when the large intrahepatic ducts are implicated.

Systemic lupus erythematosus and chronic intestinal pseudoobstruction

We describe the first case of a patient with systemic lupus erythematosus in which clinical and radiological features, small bowel manometry and histological studies were consistent with the diagnosis of chronic intestinal pseudoobstruction. Our patient developed a fatal form of lupus with cerebral angiitis and tubulointerstitial lupus nephritis, with no sign of progressive systemic sclerosis or dermatopolymyositis. Postmortem examination confirmed the presence of an extensive fibrotic process in the muscularis layers, whereas the muscularis mucosae and the innervation of the digestive wall were spared.