Cryptococcal meningitis in human immunodeficiency virus (HIV)-positive and HIV-negative patients.

This study compared clinical manifestations, blood biochemistry and cerebrospinal fluid (CSF) results of HIV-positive and HIV-negative patients with cryptococcal meningitis. We collected 57 cases of cryptococcal meningitis from cytological specimens submitted to the Department of Tropical Pathology, Faculty of Tropical Medicine. Pertinent clinical data were analyzed retrospectively in 47 cases for clinical manifestations, laboratory features and outcomes of 38 HIV-positive and 9 HIV-negative patients. Headache was the most common symptom seen in all cases, of which 70.2% occurred with fever. CSF examination of both groups revealed elevated opening pressure. Increased CSF protein and depressed CSF glucose levels were seen in HIV-negative cases, which differed from HIV-positive cases, where a slight change was noted. CSF pleocytosis in HIV-positive patients was variable. Forty-eight percent of HIV-positive patients had CSF leukocyte counts below 20 cells/ mm3. None was found in the HIV-negative patients. Specific treatments with amphotericin B and fluconazole were given. Five fatal cases of cryptococcal meningitis were noted, all of which were HIV-positive. There were statistically significant differences in blood neutrophils, blood eosinophils, CSF leukocyte counts, CSF neutrophils, CSF lymphocytes, CSF glucose, and CSF total protein, in HIV-positive and HIV-negative patients (p = 0.050, p = 0.022, p = 0.002, p = 0.016, p = 0.047, p = 0.031, p = 0.009, respectively).

Cerebrospinal fluid analysis in eosinophilic meningoencephalitis.

Eosinophilic meningoencephalitis (EME) remains an important neurological disease and is widely distributed in Thailand. We analyzed the cytological specimens of 56 EME cases. Pertinent clinical data were analyzed retrospectively and correlated with the cerebrospinal fluid (CSF)analysis. Headache was the commonest symptom seen in all EME cases. History of raw or partially cooked Pila snail ingestion was elicited from most patients. There was a marked seasonal occurrence between July to January. Patients received specific treatment as supportive therapy, which included spinal taps, analgesics and corticosteroids, was adequate. No fatal cases were seen. The CSF specimens were sorted into two categories: fresh CSF and hematoxylin and eosin (H&E) stained centrifuged CSF sediment. There was a statistically significant difference between the number of eosinophils and lymphocytes of fresh CSF and the H&E stained centrifuged CSF sediment (p = 0.001 and 0.001 respectively). The CSF glucose and the number of eosinophils in both methods were significantly correlated (p = 0.000, p = 0.008 for fresh CSF and the H&E stained centrifuged CSF sediment respectively). Moreover, the number of eosinophils was statistically significant with the protein in the CSF (p = 0.013), and intracranial pressure (ICP) (p = 0.025). Higher yields of eosinophils, especially in the early course of the disease, can readily be detected in the H&E stained centrifuged CSF sediment, whereas fresh specimens were negative. Further tests may increase the sensitivity and specificity of EME diagnostic results.

Opportunistic infections in the liver of HIV-infected patients in Thailand: a necropsy study.

Liver necropsy from patients infected with human immunodeficiency virus was analyzed in 117 cases. Wide ranges of opportunistic infections were recorded in 47%. Cryptococcosis (21.4%) was the most outstanding infection, followed by tuberculosis (16.2%), cytomegalovirus (5.1%) and penicillosis (3.4%). Non-specific alterations of the liver tissues included fatty steatosis (49.6%), fibrosis (55.6%), portal inflammation and reactive hepatitis. Cases of chronic active and chronic passive hepatitis and one case of hepatocellular carcinoma were reported. In the infected liver, predominant pathological changes included granuloma and spotty necrosis, which were attributed to tuberculous hepatitis. Infection with Cryptococcus usually showed no associated pathological change. The sensitivity for the clinical diagnosis of Cryptococcus was 88.8% and specificity was 91.7%. For tuberculosis, sensitivity was 20% and specificity was 67.9%.

Absence of knobs on parasitized red blood cells in a splenectomized patient in fatal falciparum malaria.

We present a case report of fatal falciparum malaria of a splenectomized adult Thai patient. The patient developed high peripheral parasitemia and showed signs of severe malaria with multiorgans involvement. Ultrastructure of Plasmodium falciparum-infected red blood cells in a fatal splenectomized patient and pathological features are reported for the first time with special emphasis on the role of the spleen as a modulating cytoadherence phenotype of parasitized red blood cells (PRBC). In this patient, adherence of the PRBC to the vascular endothelium of brain, kidney and lung including blood circulating cells, was noted, despite the absence of knob on the surface of the PRBC.

Cytokines associated with pathology in the brain tissue of fatal malaria.

Cytoadherence of Plasmodium falciparum-infected erythrocytes to the brain microvascular endothelial cells is believed to be an important cause of circulatory blockage in cerebral malaria. Cytokines released during acute infection may activate brain endothelial cells leading to increased binding of infected erythrocytes in the brain and reduced cerebral blood flow. This effect may be direct and more potent with the tissue-localized cytokines in the brain. In order to establish this relationship, brain tissues of cerebral and noncerebral malaria were compared. The most prominent histopathologic changes in the brain included edema, neuronal degeneration, ring hemorrhage, and percentage of parasitized erythrocytes sequestration were observed in cerebral malaria. Immunohistochemical staining of the brain sections demonstrated that tissue-localized TNF-alpha, IFN-gamma, IL-I1B, and IL-10 were associated with the histopathology. However, IL-4 was the only cytokine presented at moderate level in the brain tissue of noncerebral malaria which histopathology was the least. No tissue-localized cytokine was observed in the brain of P. vivax infection or of the car accident control cases.

Herpes simplex virus type-2, cytomegalovirus and Epstein-Barr virus infection in acute non A to E hepatitis Thai patients.

A significant number of acute non A to E hepatitis cases are reported in Thailand every year, and the etiologies of these cases are unknown. Members of the herpesviridae family have been reported to cause either a self limited or fatal hepatitis in a small proportion of patients in other parts of the world. To determine whether herpesviruses may play a role in acute non A to E hepatitis, sera from 32 acute hepatitis patients without markers for acute hepatitis A to E virus infection were examined for IgM to herpesvirus type 2 (HSV-2), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) using commercially available assays. IgM to HSV-2 was detected in four sera, IgM to CMV was detected in one serum, and IgM to EBV was detected in one serum. All of the acute non A to E hepatitis patients recovered and none had underlying conditions associated with impaired immunity. These results suggest that herpesviruses should be considered in the differential diagnosis for Thai patients with hepatitis.

Etiology of acute non-A, B, C hepatitis in Thai patients: preliminary study.

To better characterize the etiology of acute non-A, B, C hepatitis, 24 sera from 50 acute hepatitis without acute markers for hepatitis A, B, and C were examined for acute markers for the hepatitis E virus (HEV), cytomegalovirus (CMV), herpes simplex virus type 2 (HSV-2), and Epstein-Barr virus. Immunoglobulin M (IgM) specific for HEV, HSV-2, and CMV was detected using ELISA and total Ig specific to EBV was determined by standard indirect immunofluorescence. IgM to CMV was not observed in sera from any of the patients; whereas, IgM to HEV was detected in sera from 2 patients and IgM to HSV-2 was detected in 5 of 24 acute hepatitis patients. In addition, high titer of antibody was found in 2 of the patients. This results indicate that HSV-2 and HEV circulate in Thailand and are responsible for a small proportion of non-A, B, C hepatitis in Thailand.

Localization of Vibrio cholerae O1 in the intestinal tissue.

Colonization of V. cholerae O1 in vivo is known to be a non-invasive type which the vibrios are confined only to the intestinal tissues. The pathway by which the vibrio antigens reach the lymphoid cells and subsequently give rise to the immune responses is not entirely clear. Thus, experiments were performed in experimental rats by inoculating live V. cholerae O1 into the ligated ileal loops. The fate of the vibrios in the intestinal tissues was then studied by transmission electron microscopy at different times after the inoculation. It was concluded that live V. cholerae O1 were initially taken up by the M cells which overlay Peyer's patches and which subsequently delivered the intact vibrios to phagocytic cells in the Peyer's patches. These phagocytic cells processed (digested) the vibrios while the lymphocytes and plasma cells infiltrated around them. During the late period of infection (12-15 hours after inoculation of the vibrios), vibrios were also found passing through the loose intercellular spaces between the absorptive epithelial cells into the underlying intestinal tissues.

Immunogenicity of liposome-associated oral cholera vaccine prepared from combined Vibrio cholerae antigens.

Liposomes were prepared from bovine brain sphingomyelin and cholesterol. They were reinforced by incorporation of osmium tetroxide to prevent their immediate degradation inside the host. Combined Vibrio cholerae antigens (lipopolysaccharide, crude cell-bound hemagglutinin and procholeragenoid) were orally administered to experimental rats either as free or liposome-associated. A total of 70 experimental rats was utilized in experiments comparing the immune responses of rats to liposome-associated vaccine, free vaccine, liposomes, or placebo, and to vaccines where the lipid or antigen levels were reduced. Immediately after feeding with sodium bicarbonate to lower the gastric acidity, they were fed either cholera vaccines or placebo. Results from serum ELISA revealed that the liposomes localized the immune response to the intestinal mucosa. They displayed an adjuvant property in terms of evoking a higher immune response to V. cholerae antigens, as measured by the appearance of specific antibody-producing cells in the intestinal mucosa, than when the antigens were fed alone. The adjuvanticity was found to be lipid dose dependent. Liposomes prepared with high lipid content enhanced immunogenicity of the admixture antigens to a greater degree.

Electron microscopic study of phagocytosis in human spleen in falciparum malaria.

The ultrastructure of the spleen of a patient who died of natural infection of Plasmodium falciparum was studied with emphasis on phagocytosis. Parasitized erythrocytes were shown to interact with the heterogenous populations of phagocytic cells. Phagocytosis occurred predominantly in macrophages than endothelial cells and immature forms of parasites were preferentially phagocytosed. Splenic trapping, pitting and destruction of both infected and noninfected erythrocytes were demonstrated. Other forms of interaction between phagocytic cells and parasitized erythrocytes observed include complex interdigitation, association of loose and tight phagosomes, and preferential sites of adherence, the significance of which need further investigation.

Spleen in falciparum malaria: ultrastructural study.

An ultrastructural study was undertaken of the spleen of 13 year-old-boy who died of falciparum malaria. The spleen revealed the following: both parasitized and non-parasitized erythrocytes are phagocytosed in large numbers by macrophages, littoral and reticular cells. Blood congestion and trapping of parasitized erythrocytes are commonly seen in splenic sinusoids and cords. Erythrocytes forming rosette structure around immuno-presenting cells is observed. The results of this study provide evidence that the mechanisms underlying splenic host defence in malaria include both immunological and non-immunological interaction with erythrocytes. Splenic trapping of parasitized erythrocytes is an important defence mechanism and the phagocytosis of erythrocytes probably accounts for anaemia.

Oral vaccine against cholera prepared from Vibrio cholerae antigen(s).

Albino rats aged 7-8 weeks old purchased from the National Laboratory Animal Centre, Salaya, Nakhon Pathom, were found to be a good animal model for the study on immunogenicity of V. cholerae antigens. Seventy-two rats were fasted for 15 hours before feeding each one with 1 ml of 5% NaHCO3 to reduce gastric acidity prior to immunization. They were divided into 9 groups of 8 rats and immunized orally with 2 ml, each, of the V. cholerae antigens dissolved or suspended in Cassamino acid as follows: group 1 (control): Cassamino acid (Ca) alone; group 2 (control): 2.5% formalinized sheep red blood cells (F-SRBC); group 3: 1,000 micrograms of lipopolysaccharide (LPS); group 4: 100 micrograms of procholeragenoid (P); group 5: 80 haemagglutinating units of cell-bound haemagglutinin (CHA) adsorbed onto the surface of F-SRBC (CH-SRBC); group 6: 500 micrograms of LPS + 50 micrograms of P; group 7: CH-SRBC + 50 micrograms of P; group 8: combined vaccine formula 1 consisted of 500 micrograms of LPS, CH-SRBC and 50 micrograms of P and group 9: combined vaccine formula 2 consisted of 1,000 micrograms of LPS, CH-SRBC and 100 micrograms of P. The immunization was repeated once more 14 days later. Five days, thereafter, the rats were killed and their jejuni were removed for cryostat sectioning. Antibody producing cells against LPS (anti-LPS cells), P (anti-CT cells) and CHA (anti-CHA cells) in the intestinal lamina propria were enumerated by double antibody sandwich method of immunofluorescence using pure LPS, cholera toxin (CT) and pure CHA as the antigens in the assay, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Electron microscopy of the human brain in cerebral malaria.

Ultrastructure of erythrocytes infected with Plasmodium falciparum in human brain, obtained 3 hours post mortem revealed gross distortion of host red cells with abnormality of the red cell surface. The superficial alterations of the parasitized cells as knob-like protrusion appear to be the sites of attachment to vascular endothelium. There was evidence of platelets sticking to the injured endothelium. The endothelial vesicular membrane is in close adhesion to the parasitized red cell, and also to the platelets involved in this mechanism. Thus, explaining the sequestration of parasitized red cell and obstruction in cerebral microcirculation, cerebral oedema and low peripheral platelet count. The was no evidence of inflammation, fibrin or thrombus formation observed in our studies.