Risk factors for Helicobacter pylori infection in children: is education a main determinant?

To investigate potential risk factors associated with Helicobacter pylori (Hp) infection, we performed a case-control study in 167 consecutively selected hospitalized children in Salvador, Brazil. Hp infection was identified by the presence of IgG against Hp in serum samples. Data were gathered using a structured questionnaire, 38.3% children were found to be seropositive and classified as cases, and 61.7% were seronegative controls. After multivariate analysis, independent variables associated with Hp infection included: the educational attainment of the child's provider > or = 11 years (OR 0.1, 95% CI 0.01-0.9), poor garbage disposal service (OR 2.2, 95% CI 1.0-4.9), thumb sucking (OR 4.6, 95% CI 1.1-19.8), brushing teeth more than once a day (OR 5.6, 95% CI 1.8-17.7), having a pet dog (OR 2.5, 95% CI 1.0-6.1), and a history of chronic urticaria (OR 4.0, 95% CI 1.5-10.8). The risk factors identified are consistent with some, but not all, previous studies supporting either oral-oral or faecal-oral transmission of Hp. Our data suggested that a higher educational attainment might play an important role in preventing Hp infection.

Blood donors with 'medium' or 'minor' risk factors for human immunodeficiency virus infection: are they eligible for donation?

BACKGROUND AND OBJECTIVES: We conducted a longitudinal prospective study to assess the eligibility to blood donation of donors with 'minor' risk factors (i.e. minor surgery, professional exposure, cohabitation with 'high risk' people, occasional use of light drugs) or 'medium' risk factors for human immuno-deficiency virus (HIV) infection (i.e. casual sexual relationship, multiple heterosexual exposure, sexual partnership with subjects at risk, regular use of light drugs). DESIGN AND METHODS: During a 4-year period we administered a psychosocial questionnaire to all donors attending our Center. In addition we determined anti-HIV, anti-hepatitis C virus (HCV), hepatitis B surface antigen (HBsAg) and syphilis serology (TPHA) at entry to the study and at 6-month intervals. RESULTS: Of 25,367 donors, 1,535 (6%) reported medium and 8,761 (34%) minor risk. At enrollment into the study, 4 medium risk donors were anti-HIV positive and there was a significantly higher rate of positivity for TPHA (0.33% vs 0.07%) and anti-HCV (1.17% vs 0.63%) in this group than in donors reporting no risk. No anti-HIV positivity was observed in minor or no risk donors. During a median follow-up of 18 months, none of 24,404 donors undergoing 106,503 visits seroconverted to HIV. The incidences of novel HCV and syphilis infections were almost one log greater in donors at medium risk (3 and 1x10-4/yr, respectively) than in no risk donors (0.4 and 0.1x10-4/yr, respectively). Medium risk donors were more frequently males (Odds Ratio=3.2, 95% confidence interval= 2.8-3.7), aged 26-35 yrs (1.52; 1.3-1.78), single (1.4; 1.2-1.6), divorced (2; 1.4-2.8), freelance workers (1.43; 1.1-1.9) and first-time donors (1.8; 1.6-2.1) than no risk donors. INTERPRETATION AND CONCLUSIONS: The only 4 HIV positive subjects of the cohort were medium risk donors picked up at enrollment. No HIV seroconversion was observed during the study. On the basis of this study we will continue to defer 'medium' risk donors.

The incidence and risk factors of community-acquired hepatitis C in a cohort of Italian blood donors.

To assess the incidence and source of community-acquired hepatitis C virus (HCV) infection among subjects at low risk for blood-borne diseases, we prospectively studied a cohort of 16,515 repeat blood donors over a mean follow-up time of 36 months. Second- and third-generation methods were used for hepatitis C virus antibody (anti-HCV) testing. HCV RNA was determined in the serum of anti-HCV-positive donors by reverse-transcription polymerase chain reaction. Liver biopsy was performed in the viremic subjects. Risk factors for HCV infection were identified by a psychosocial questionnaire in the whole cohort. During follow-up, 5 donors became infected with HCV. The incidence was 1 per 10,000 person-years (95% confidence interval, 0.3-2.4 per 10,000). During the 6 months before seroconversion, four subjects (80%) underwent medical or surgical percutaneous procedures, compared with 26.5% in the entire donor cohort (difference between frequencies, 53.5%; CI: 18.9-89.1). One seroconverting donor had sexual intercourse with an infected subject. Only 1 infected donor developed clinically evident acute hepatitis. HCV RNA remained detectable in 4 of 5 subjects for 8 to 36 months after seroconversion, and liver biopsy showed chronic hepatitis in all cases. Thus, new cases of hepatitis C occur among individuals without a history of known risk factors, some of which may be caused by nosocomial exposure.

Effects of blood donation on cerebral blood flow velocity.

Eighteen healthy male blood donors, nine with hematocrit (Hct) of 0.40 to 0.45 (normal Hct) and nine with Hct of 0.49 to 0.52 (upper-limit Hct), were monitored by continuous-wave internal carotid Doppler sonography and hematologic tests for 28 days after blood donation, to ascertain whether and to what extent a single standard donation may modify the velocity of cerebral blood flow. The two groups had similar mean predonation values of internal carotid flow velocity (ICFV): blood donation was followed in both groups by a slight, transient decrease of ICFV at the end of phlebotomy, due to donation-induced hypovolemia, and then by an increase of ICFV lasting 7 to 10 days. Analysis of individual profiles revealed that only four of nine upper-limit and six of nine normal Hct donors displayed a positive trend (increase) in the ICFV within the first week after donation, and that it was due mainly to a rise in systolic flow velocity. Mean Hct and arterial oxygen content showed a negative trend (decrease) within the first week that was opposite to the ICFV trend. Other laboratory variables, including serum proteins and plasma fibrinogen concentration, and the iron status indicators did not change, except for serum ferritin, which also decreased within the first week after phlebotomy. It can be concluded that blood donation may result in a short-term increase of blood flow velocity that is independent of Hct predonation levels in approximately one-half of the donors.

Screening and evaluation of blood donors with upper-limit hematocrit levels.

Eighty-one consecutive repeat male blood donors with hematocrit levels ranging from 0.49 to 0.54 underwent hematologic investigation, blood gas analysis, and respiratory function tests in order to ascertain whether they represent the upper end of the reference distribution or have underlying causes of erythrocytosis. Three of the 81 (3.7%) proved to have early-stage polycythemia rubra vera, nine (11.1%) to have erythrocytosis secondary to respiratory failure, and two (2.4%) to have relative erythrocytosis due to reduced plasma volume. Detection and evaluation of blood donors with high hematocrit values are ways in which blood banks could contribute to health screening and become involved in preventive medicine.

Chronic granulomatous disease in a 23-year-old female.

A 23-year-old girl with clinical and laboratory findings characteristic of chronic granulomatous disease is described. The patient was admitted to hospital because of severe disseminated aspergillosis. Studies of neutrophils showed normal phagocytosis but impaired microbicidal killing and a failure of the respiratory burst activity as measured by NBT-reduction, superoxide generation, chemiluminescence and antibody-dependent cell mediated cytotoxicity. Patient's neutrophils had normal chemotactic responsiveness but a marked impairment in the level of serum chemotactic activity was observed. Neutrophils from the parents and 2 maternal aunts showed normal values for all the determinations. The lack of evidence for a carrier state in all the family members studied together with the inability to detect a mixed population of neutrophils in our patient are in contrast with the Lyon's hypothesis of X-chromosome inactivation. Our findings suggest an autosomal recessive inheritance in this female with chronic granulomatous disease.

Modifications of granulocyte subpopulations and of their adherence property during filtration leukapheresis in man.

Polymorphonuclear leucocytes (PMN) isolated from the peripheral blood of 23 blood donors undergoing filtration leukapheresis were examined with regard to their number, expression of membrane receptors for rabbit IgG or human C3b and their ability to adhere to nylon fibres. All the donors showed an early granulocytopenia followed by a gradual return of PMN into the circulation, but differed in the number of PMN appearing in the rebound phase. Evaluation of rosette forming cells (RFC) and cells adhering to nylon fibres in this phase led to the recognition of two main groups of donors. In one of these groups the number of PMN, RFC and adhering cells remained unchanged compared to the pre-apheresis values. The other group showed marked leucocytosis accompanied by a relative increase in the number of non-RFC and non-adhering cells. Possible mechanisms involved in the changes of PMN subpopulations are discussed.

A modified 'low pH' lignocaine method to isolate human monocytes: a comparison with other separation procedures.

A modified 'low pH' lignocaine method for the recovery of human monocytes from untreated plastics is described and compared with other adherence separation procedures, viz. mechanical scraping by a rubber policeman, microexudate-coated plastic method and pretreatment of plastics by the fetal calf serum (FCS). Monocytes separated by each of the above-mentioned techniques carried out in parallel were characterised by morphological and functional criteria: non-specific esterase staining, contamination by T- and B-lymphocytes, viability, adherence, neutral red uptake, phagocytosis of yeast particles, random mobility, chemotaxis, and tumoricidal activity both in the absence and in the presence of interferon and lymphokines. The 'low pH' lignocaine method appears to be a simple and reproducible technique for the isolation of human monocytes. It seem preferable to other adherence procedures inasmuch as it yields viable, pure and functionally intact monocytes without requiring preconditioned plastics.