Morbidity from malaria and immune responses to defined Plasmodium falciparum antigens in children with sickle cell trait in The Gambia

Morbidity from Plasmodium falciparum malaria and humoral and in vitro cellular immune responses to defined malaria antigens were measured in rural Gambian children with haemoglobin phenotype AS (HbAS) and in those with a normal haemoglobin (HbAA). In a survey undertaken during the dry season, HbAS children had a higher parasite rate than HbAA children but a lower prevalence of parasitaemia at a level of 500/microliters or greater. Malariometric indices measured during a rainy season survey were similar in the 2 groups of children. During the rainy season, the incidence of infection with P. falciparum did not vary with haemoglobin phenotype. However, in children aged 6 years or less, a significantly smaller proportion of HbAS children who acquired infection developed clinical symptoms than did HbAA children. During both the dry season and rainy season surveys, humoral and in vitro cellular immune responses to defined antigens from the sporozoite and merozoite stages of P. falciparum were similar in the 2 groups of children. Thus, despite the differences in parasite indices and morbidity from malaria between the 2 groups of children, we found no evidence of an enhanced immune response to malaria infection amongst HbAS children compared with normal children.

Recognition of dominant T cell-stimulating epitopes from the circumsporozoite protein of Plasmodium falciparum and relationship to malaria morbidity in Gambian children

Cellular immune responses to the Plasmodium falciparum circumsporozoite (CS) protein were measured by proliferation and interferon-gamma production in a cohort of children aged 3 to 8 years, living in The Gambia. Anti-CS antibody titres, malariometric indices and sickle cell status were also determined. Malaria morbidity in the ensuing malaria transmission season was monitored by weekly health questionnaire, axillary temperature measurements and examination of blood films. Exposure to malaria was inferred from entomological data collected during the transmission season. Immunological and parasitological measurements were repeated at the end of the rainy season. Immunological findings were compared between children who experienced clinical malaria or asymptomatic infection and children who had no evidence of infection. No association was found between cellular immune responses to the CS protein at the beginning of the transmission season and subsequent susceptibility to infection except among children with high titres of antibody to (NANP)40. Seropositive children who did not become infected had a higher mean proliferative response to the Th3R epitope than seropositive children who did become infected. High titres of anti-(NANP)40 antibodies alone were not protective. Responses to the Th2R epitope were significantly higher at the end of the rainy season than at the beginning in children who experienced an asymptomatic infection. Responses to variant sequences of the 2 epitopes were highly correlated at an individual level but there was no correlation between proliferative and interferon responses to a particular epitope.

Ventriculo-bronchial fistula: a rare cause of intermittent massive hemoptysis

A 44-year-old man presented with massive hemoptysis. Bronchoscopy followed by surgical exploration revealed a left ventriculo-bronchial fistula related to previous ventricular surgery. Repair was successful.

Platelet intracellular free calcium concentration in normotensive and hypertensive pregnancies in the human

1. Basal and stimulated platelet intracellular free calcium concentrations were measured in non-pregnant women and in third trimester patients who were either normotensive or who had pregnancy-induced hypertension or pre-eclampsia. There were 15 subjects in each group. 2. A trend for a reduction of the maximal response of platelet calcium levels to stimulation by 5-hydroxytryptamine was seen in pregnant groups compared with nonpregnant subjects, but this was significant only in pre-eclampsia. 3. No significant differences in basal or adenosine 5'-pyrophosphate-stimulated levels of platelet intracellular free calcium concentration were observed between the four groups. 4. These results illustrate that basal platelet calcium levels are unchanged in hypertension of pregnancy. Alterations in basal platelet calcium levels may not be involved in the platelet activation that is a feature of pre-eclampsia.

Pulmonary complications of percutaneous nephrostomy and kidney stone extraction

Percutaneous nephrostomy and percutaneous removal of kidney stones are widely used procedures that obviate the need for open urologic surgery in many patients. In six patients who had percutaneous renal manipulation, pulmonary complications of varying severity developed, including urinothorax, pneumothorax, hemorrhage, pleural effusion, pneumonia, and atelectasis. Patients having percutaneous renal manipulation should be monitored during and after the procedure for pulmonary complications.

Jones-Hedman walker modification for C7 quadriplegic patient: case study in team cooperation

A 20-year-old man with C7 quadriplegia was admitted to a tertiary care rehabilitation facility 1.5 months after discharge from an acute care community hospital. The patient's goals were to improve his skills in activities of daily living to a level of maximum independence, and to walk. Although his high level of spinal cord injury made ambulation unlikely, an occupational therapist and a rehabilitation engineer, working together, devised a method to help the patient meet his ambulation goal. They modified an ordinary walker by fabricating polyvinyl chloride-acrylic alloy guards lined with foam to reduce palmar pressure. The patient was then able to use wrist and finger extension during walker advancement and was able to ambulate 300m with Craig-Scott orthosis. The case illustrates the importance of a skilled interdisciplinary team in a specialized center for management of spinal cord injured patients.

Enhancement of the indirect anti-platelet antibody test and its application to platelet immunology

Comparisons in the same patients of platelet-bound anti-platelet antibody (APA) levels (direct test) with serum APA levels (indirect test) frequently do not give the same results. Indirect test results frequently are negative or marginally elevated even though platelet-bound antibody is greatly increased on direct testing. The most likely cause for these differences between the two tests is insufficient binding of serum antibody to test platelets in vitro. In an effort to enhance in vitro antibody binding, we examined four test modifications affecting platelet attachment. Rabbit anti-human platelet antisera (absorbed with their specific human donor leukocytes to remove HLA- and granulocyte-specific antibodies) were combined under various conditions with human platelets and tested in a modified antiglobulin consumption test utilizing rabbit IgG. The test conditions varied: incubation time of the serum APA-platelet mixture at 37 degrees C; age of the test platelet pool; ionic strength of the mixture (varied through incorporation of a low-ionic-strength solution (LISS); and vortex agitation for 30 seconds prior to the addition of sera. Optimal attachment in standard phosphate-buffered saline took place in 60 minutes using test platelets stored for either 3 or 30 days, and yielded mean values for rabbit immune sera of 9.9 fg of IgG per platelet. Preincubation controls yielded a mean of 0.7 to 1.5 fg per platelet. Incorporation of LISS or vortexing of test platelets did not affect the results of control, but both modifications substantially increased test values of immune sera to 15.8 and 17.3 fg of IgG per platelet, respectively. Combining LISS with vortexing did not further increase values.

Thermoregulation in spontaneously hypertensive rats: effects of antihypertensive treatments

Colonic temperature was measured in spontaneously hypertensive (SHR), Wistar Kyoto (WKY) and Wistar Charles River (WIS) rats. The SHRs had higher basal temperature and their temperature decreased more rapidly when exposed to 4 degrees C than temperature of controls. During exposure to 37 degrees C for 2 hrs no controls but majority of SHRs died. Treatment with clonidine (1 mg/kg, b.i.d., 14 days), hydralazine (10 mg/kg, b.i.d., 14 days) or diuretics (chlorothiazide 100 mg/kg + spironolactone 10 mg/kg, q.d., 21 days) decreased blood pressure of SHRs but did not normalize their body temperatures and heat sensitivity. These results indicate thermoregulatory dysfunction in SHRs which is probably of central origin.