Genotypic, clinical, and demographic characteristics of children infected with Helicobacter pylori

Helicobacter pylori isolates vary between geographic regions. Certain H. pylori genotypes may be associated with disease outcome. Thirty-eight children underwent diagnostic upper endoscopy at four medical centers and were retrospectively analyzed to determine if H. pylori virulence genes were associated with endoscopic disease severity, histologic parameters, and host demographics. The H. pylori virulence genotype was analyzed by a reverse hybridization line probe assay and type-specific PCR. Endoscopic ulcers or erosions were found in 17 (45%) patients, with 13 (34%) of these patients having antral nodularity. Histological gastritis, of varying severity, was present in all children. Four patients harbored more than one H. pylori strain: one subject had both cagA(+) and cagA-negative strains, while three patients harbored either two different cagA-negative strains (two children) or two cagA(+) strains (one child). There were 28 (74%) cagA(+) isolates; 19 were associated with the vacA s1b genotype, 7 were associated with the vacA s1a genotype, 1 was associated with the vacA s1c genotype, and 1 was associated with the s2 genotype. Of 14 cagA-negative isolates, 6 were vacA s2 genotype, 4 were vacA s1b, 3 were vacA s1a, and 1 was vacA s1c. Nine of ten (90%) Hispanics had similar H. pylori strains (vacA s1b,m1), and all Asian-Canadian children were infected by strains with vacA s1c genotype. No correlation between H. pylori strain and endoscopic or histopathologic abnormalities was found. This study provides a baseline framework of North American children and their H. pylori strains, serving as a powerful epidemiological tool for prospective investigations to better understand the transmission and evolution of diverse disease outcomes.

Characteristics of Helicobacter pylori infection in Jamaican adults with gastrointestinal symptoms

Helicobacter pylori infection is common in Jamaica. Describing its epidemiology in a population-based study depends largely on serology, but serologic assays have not been validated in this population. To address this issue, we examined the presence of H. pylori infection in 30 sequential adult patients with gastroduodenal symptoms by three biopsy-based methods (rapid urease test, histology, and culture) as well as by one research and two commercial enzyme-linked immunosorbent assays (ELISAs). A patient was considered H. pylori positive if the organism was detected by at least one biopsy-based method. Eighteen (60%) of the 30 patients were H. pylori positive by these criteria, whereas 21 (70%) were seropositive for H. pylori immunoglobulin G by our research ELISA. The presence of H. pylori infection in patients with gastric cancer and those with chronic gastritis was missed by biopsy-based methods but was detected by serologic assays. This observation indicates that serologic assays may be better suited for the detection of this infection in a population in which H. pylori-associated pathology is prevalent. The performance of our research ELISA in detecting biopsy-based H. pylori-positive cases was excellent, with a sensitivity and specificity of 100% and 75%, respectively. Molecular genotyping of the isolates revealed that the predominant H. pylori genotypes in this cohort of Jamaicans were cagA(+) vacA slb-m1, and iceA2. The validated serologic assay enables us to interpret epidemiologic data from population-based studies in Jamaica by comparison to those from other populations.

Effect of food on the pharmacokinetics and bioavailability of oral imiquimod relative to a subcutaneous dose

OBJECTIVES

The present study, the first clinical pharmacokinetic report of the immune response modifier imiquimod, was conducted to assess the effect of food on the oral absorption of imiquimod, to characterize its pharmacokinetics, and to estimate its oral bioavailability.

SUBJECTS AND METHODS

Sixteen healthy male volunteers completed this open-label, randomized, three-period crossover study. Subjects received a 100 mg oral dose of imiquimod after fasting in one period, after a standarized, high fat meal in another, and a 30 mg subcutaneous dose in the third period.

RESULTS

The oral bioavailability of imiquimod was on average 47%, and independent of whether imiquimod was administered with or without food. Oral imiquimod was absorbed in both fasted and non-fasted states with an absorption half-life of approximately 1 hour. However, there seemed to be a delay in the initiation of the absorption process when food was administered, which translated in to a Tmax of approximately 2.6 hours while fasting and one hour later in the non-fasted state. Imiquimod was rapidly eliminated with a half-life of approximately 2.5 hours and a total body clearance of approximately 970 ml/hxkg. Although equivalence could not be established due to the large intersubject variability, no significant differences in rate (Cmax) and extent (AUC) of oral absorption were observed between the fasted and non-fasted states. In addition, the Cmax, AUC and bioavailability values for individual subjects were consistent between both oral treatments.

CONCLUSION

This study suggests that food does not have a major effect on the rate, extent of absorption or bioavailability of oral imiquimod, and thus, it is suitable to administer imiquimod orally in either the fasted or non-fasted states.

The hemodialysis access: preferences and concerns of patients, dialysis nurses and technicians, and physicians

One hundred twenty-eight hemodialysis patients and 64 medical personnel consisting of dialysis nurses and technicians, hemodialysis access surgeons and nephrologists were surveyed about their preferences and concerns in regard to the hemodialysis vascular access. The access preferred by physicians was the A-V fistula in the lower arm. In contrast, the access preferred by dialysis nurses and technicians was the polytetrafluoroethylene (PTFE) graft in the lower arm. Patients desired a superficial access in the forearm which was easy to cannulate, had minimal effect on their appearance, provided quick hemostasis after dialysis and enabled arm comfort during dialysis. Physicians felt the most significant concerns about the access were thrombosis and infection. Nurses and technicians ranked difficult cannulation and insufficient access blood flows that prohibited dialysis adequacy as their major problems. For patients the most common problem was pain during needle insertion. This survey concluded that the A-V fistula remains the access of choice. However, appropriate maturation of the fistula must occur before needle insertion is attempted. An immature fistula is difficult to cannulate, has fragile veins resulting in blood leakage around the needle infiltrating the subcutaneous tissues and has inadequate blood flows for successful dialysis. Patients who are introduced to dialysis with inadequate access function or access failure from either an A-V fistula or a PTFE graft have increased morbidity, inadequate dialysis and enhanced anxiety about dialysis treatments. To increase the success and acceptance of A-V fistulas in hemodialysis patients it is incumbent upon the nephrologist to protect the future access arm from damage to the vasculature and to allow for fistula maturation before cannulation. Surgical protocols must improve the appropriate selection of a fistula or PTFE graft for various age groups and disease categories. Better patient preparation and selection of the proper access type for each patient will enhance early access function and subsequent access survival.

Assessing attachment: convergent validity of the adult attachment interview and the parental bonding instrument

OBJECTIVE

The aim of this study was to determine whether or not the Parental Bonding Instrument (PBI) can provide information about parent-child attachment that is comparable to information obtained from the Adult Attachment Interview (AAI), a more complex measure of attachment.

METHOD

One hundred and thirty emotionally and/or behaviourally disturbed adolescents (73 male, 57 female; ages 13-19 years, x = 15.3 +/- 1.47 years) participating in a study of attachment and suicidality completed the PBI and the AAI. Data from these measures were compared within participants.

RESULTS

Maternal care and overprotection on the PBI differed significantly by AAI attachment classification (F3,122 = 2.79, p = 0.012), with autonomous participants showing the most optimal and unresolved participants the least optimal PBI results. Maternal love and maternal involvement/role reversal on the AAI were significant predictors of maternal care and maternal overprotection, respectively, on the PBI (R2 = 0.15; R2 = 0.16). These predictions improved when AAI scales measuring idealisation and involving anger towards the mother were included in the regression analyses (R2 = 0.35; R2 = 0.20). Autonomous participants on AAI showed the highest scale correlations across instruments.

CONCLUSIONS

Attachment information obtained from the PBI and the AAI is comparable in participants with optimal attachment histories, but not in participants showing idealisation or anger towards their mothers. Caution is, therefore, advisable when using the PBI to obtain attachment information in clinical samples where suboptimal attachment histories are likely.

Administration of imiquimod, an interferon inducer, in asymptomatic human immunodeficiency virus-infected persons to determine safety and biologic response modification

A phase I study to determine safety, maximum tolerated dose, and biologic response during multiple once-a-week administration of oral imiquimod, an immune response modifier, was conducted in 12 adults with early human immunodeficiency virus (HIV) infection. All completed the dose-escalation phase of weekly dosing at 100-mg increments and received at least one maintenance dose, 100 mg below the patient's toxic dose, for 12 weeks. Dose-limiting toxicity occurred in 3 patients at 200-mg, 5 at 300-mg, and 3 at 400-mg dose levels. One tolerated the 500-mg dose without dose-limiting toxicity. Dose-limiting toxicities included fatigue, fever, malaise, increased transaminases, hypotension, vomiting, and depression. Seven of 12 completed 12 weeks of maintenance. At > or = 200 mg of imiquimod, all patients had biologic responses, measured by elevations in serum interferon, beta2-microglobulin, and neopterin levels. Imiquimod induced pronounced levels of circulating interferon in asymptomatic HIV-infected persons, with variable effect on virus load.

A phase I clinical trial of imiquimod, an oral interferon inducer, administered daily

Imiquimod is an orally active interferon inducer with anti-tumour activity in experimental animals. In this study the tolerability, toxicity and biological effects of daily oral imiquimod administration were investigated in 21 patients with refractory cancer. Patients were treated with doses of 25 mg, 50 mg, 100 mg or 200 mg on a projected 112 day course. Only three patients completed the course, all at the 50 mg dose. Treatment toxicities were dose related and mainly comprised flu-like symptoms, nausea and lymphopenia. Of the 21 patients, five received dose reductions and in five treatment was discontinued because of treatment-related toxicity. The biological activity of imiquimod was confirmed by significant and sustained rises in peripheral blood mononuclear cell (PBMC) 2-5A synthetase (2-5AS) levels at all doses. At 100 mg and 200 mg these occurred within the first 24 h of administration. Levels of neopterin and beta 2-microglobulin (beta 2M) were also significantly elevated when assessed after three weeks' treatment. Interferon production was not demonstrated within the first 24 h of the initial dose but, following repeated doses, ten of the patients developed detectable serum interferon concentrations with a maximum value of 5600 IU ml-1 recorded. Administration of imiquimod did not have any significant effect on serum levels of tumour necrosis factor (TNF) or interleukin 1 (IL-1), nor did it lead to development of detectable levels of antibodies to interferon. One mixed clinical response was observed after 4 weeks' treatment at 100 mg in a patient with renal cell cancer. Daily administration of imiquimod causes activation of the interferon production system but at higher doses results in unacceptable toxicity. Further investigation of imiquimod as an interferon-inducing agent in cancer patients is suggested at either the lower dose levels or employing alternative dosing schedules.

Care of a woman with Down's syndrome using the Neuman Systems Model

Care study

Alice Bird is a 26-year-old women with Down's syndrome and a severe learning disability. Following a long illness, Alice's father passed away just before my involvement with the family. Alice now lives at home with her mother, aged 70, and an older sister, Janice, aged 34, who has a mild learning disability and is also being treated for mental health problems.

Two other brothers live nearby and are in regular contact with the family. My initial contact with this family followed a request for help in planning long-term care for Alice in the event of the mother's death. Mrs Bird, having recently lost her husband, realised that her daughter would almost certainly live longer than her and wanted to feel that appropriate plans had been made.

Membrane glycoproteins in cryopreserved platelets

Although platelets stored by cryopreservation are effective in hemostasis, they acquire a number of functional defects during storage and preparation for transfusion. In addition to known acquired defects such as defective aggregation, decreased resistance to hypotonic shock, and disc-spherocyte transformation, we have shown that cryopreserved platelets have decreased capacity to adhere to subendothelium, compared to liquid-stored platelets. To investigate this decrease in adhesive capacity of cryopreserved platelets, we measured the major adhesive membrane glycoprotein, GPIb, and the principal aggregatory protein, GPIIb/IIIa, using flow cytometry in fresh platelets or in platelets cryopreserved in 5% DMSO. We also analyzed aggregation of cryopreserved platelets or liquid-stored platelets in response to ristocetin as another measurement of GPIb functional capacity. We found that approximately 15% of cryopreserved platelets lost surface-bound GPIb, while there was no measurable loss of GPIIB/IIIa during cryopreservation. The cryopreserved platelets also showed a significant decrease in aggregation to ristocetin, but no loss of response to the stronger agonist, thrombin. The loss of surface GPIb from cryopreserved platelets was modest in degree, approximately that reported for liquid-stored platelets, and does not seem great enough to account for the observed functional changes in aggregation and adhesion.

Use of bone for obliteration of the nasofrontal duct with the osteoplastic flap: a cat model

The management of the frontal sinus remains controversial for traumatic and inflammatory disease. The osteoplastic flap with fat obliteration has become the treatment standard, although late failures with infection and mucocele formation may arise. Theories for mucocele formation include regrowth of residual mucosa from the sinus and ingrowth of mucosa from a nonobliterated nasofrontal duct. A study to evaluate the means of nasofrontal duct obliteration was developed. Three cat groups were evaluated at 1, 2, and 3 months. Group 1 had the duct and sinus obliterated with fat. Group 2 had the duct obliterated with bone and the sinus with fat. Group 3 had only the duct obliterated with bone. There was no mucosal ingrowth in any of the sinuses for the intervals studied. In group 1, fat volume was seen to decrease over time with replacement by fibrous tissue within the duct. Groups 2 and 3 developed progressive obliteration of the duct with new bone formation. One may infer that fat obliteration alone does not provide a predictable stable situation as fat atrophies within the duct and may allow mucosal ingrowth. Bone obliteration was shown to be progressive within the duct from osteogenesis. This is the first experimental model to correlate clinical observations of the use of bone for sinus obliteration. This study concluded that bone obliterates the nasofrontal duct better than the accepted standard of fat, independent of the material used to obliterate the sinus.

Clostridium difficile: clinical disease and diagnosis

Clostridium difficile is an opportunistic pathogen that causes a spectrum of disease ranging from antibiotic-associated diarrhea to pseudomembranous colitis. Although the disease was first described in 1893, the etiologic agent was not isolated and identified until 1978. Since clinical and pathological features of C. difficile-associated disease are not easily distinguished from those of other gastrointestinal diseases, including ulcerative colitis, chronic inflammatory bowel disease, and Crohn's disease, diagnostic methods have relied on either isolation and identification of the microorganism or direct detection of bacterial antigens or toxins in stool specimens. The current review focuses on the sensitivity, specificity, and practical use of several diagnostic tests, including methods for culture of the etiologic agent, cellular cytotoxicity assays, latex agglutination tests, enzyme immunoassay systems, counterimmunoelectrophoresis, fluorescent-antibody assays, and polymerase chain reactions.

Surfactant protein-A inhibits lavage-induced surfactant secretion in newborn rabbits

In vitro experiments with granular pneumocytes suggest that surfactant protein-A (SP-A) inhibits secretion of pulmonary surfactant. We examined whether SP-A inhibits surfactant secretion induced by lung distention during lung lavage. Human SP-A was obtained by lung lavage in a patient with pulmonary alveolar proteinosis. After centrifugation of the lavagate, the pellet was repeatedly washed with saline and then extracted with chloroform:methanol. The methanol:saline phase was separated and lyophilized to yield the SP-A product. SDS-PAGE and immunoblot analysis indicated that our preparation of SP-A had only minor contamination with human plasma proteins. To examine secretion, we used freshly killed newborn rabbit pups of 29.5 days gestation and lavaged the lungs by 10 sequential, fresh saline washes. Littermate neighbor pairs were lavaged with SP-A or human plasma protein at concentrations of 1, 6, 10, and 50 micrograms/ml, and disaturated phosphatidylcholine (DSPC) was analyzed as a marker for surfactant. The inhibition of surfactant secretion was maximal at a concentration of 10 micrograms/ml; the average yield by the last two pairs of washes, an index of surfactant secretion, was 286 +/- 41 micrograms/g dry lung weight for SP-A, compared to 405 +/- 37 micrograms/g dry lung weight for controls, an inhibition of 30% (p < 0.005). There were no changes in the volumes of returned lavage or in the concentrations of lactate dehydrogenase or DNA. To test whether SP-A increased cellular uptake of DSPC in the lungs, we prepared radioactive exogenous surfactant, lavaged it into the lungs, and monitored recovery of radioactivity by continued lavage. Recovery was the same in treated and control lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacologic action of Escherichia coli heat-stable (STa) enterotoxin

Escherichia coli produces a heat-stable (STa) enterotoxin that belongs to a family of peptides that mediate several diarrheal diseases, including traveler's diarrhea and epidemic diarrhea in infants and newborns. The STa enterotoxin consists of 18 or 19 amino acids and is encoded by genes specified on a transposon. Intestinal secretion is induced by specific binding to high affinity receptors that reside on the brush border cell membrane of the small intestine. Receptor activation by STa enterotoxin induces a sequence of events that culminate in the release of fluid and electrolytes into the intestinal lumen. These events include the stimulation of particulate guanylate cyclae and subsequent increase of intracellular cyclic GMP, involvement of particulate protein kinase, elevation of intracellular calcium, and activation of the phosphatidylinositol pathway. The release of archidonic acid and production of prostaglandins and/or leukotrienes have also been implicated in the action of STa. Evidence indicates that the STa enterotoxin receptor may be a single multifunctional membrane protein.

Improved post-transfusion quality of density separated AS-3 red cells after extended storage

A centrifugal method of red cell density separation was utilized for unit processing in these studies to determine the quality of the lighter fraction (neocytes) after storage for up to 42 d and to evaluate whether the heavier fraction (gerocytes) deteriorated more rapidly than neocytes during storage. Each unit was passed through a Leukotrap filter to remove white cells prior to density separation. Red cell recovery and survival were evaluated using double label technetium-99m with either chromium-51 or nonradioisotopic chromium which permitted concurrent paired analysis. In vivo neocyte red cell recovery, as tested on the same 11 donors on days 1, 7 and 42 of storage, was effectively unchanged. Recovery and survival half-life (that is, the number of days after transfusion at which half of the cells infused remain in the circulation) of 42 d stored gerocytes were significantly lower than similarly stored neocytes (75.5 +/- 7.2% and 20.1 +/- 6.5 d for gerocytes versus 84.4 +/- 4.9% and 39.0 +/- 9.0 d for neocytes). One-day stored neocytes showed a 16.5% increase in red cell availability over the combined average for 42 d stored neocytes and gerocytes. Statistically, while there were significantly higher ATP, 2,3-DPG, and lactate levels pre-storage by paired t-test for neocytes compared to gerocytes, by day 42 there were no significant differences detected between the two red cell fractions by any of the in vitro variables measured. These studies suggest that this simple separation technique for leucocyte-poor red cell units provides a neocyte population with improved viability and the potential for increased transfusion intervals in chronically transfused patients.