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Biomedical subjects

B Case

Publications and source records attributed to B Case.

At least 19 recordsLinked to original sources
PubMed2006

Changes in tumour oxygenation during fractionated hyperthermia and radiation therapy in spontaneous canine sarcomas.

Tumour oxygenation was measured in seven canine soft tissue sarcomas being treated with a fractionated course of radiation and hyperthermia. Measurements obtained during treatment were compared to pre-treatment measurements. The most important finding was an increase in oxygenation in tumours with low pre-treatment oxygenation that persisted throughout treatment. This is an advantageous hyperthermia effect as it may lead to increased radiation cell killing at each fraction. In other tumours, potentially less advantageous changes in oxygenation may be hyperthermia fractionation related and this deserves further investigation.

Animals↗
PubMed2001

Child hospitalization: an opportunity for parental smoking intervention.

BACKGROUND: Hospitalization with tobacco-related illness increases smokers' interest in cessation. Because parental smoking increases the child's risk of developing respiratory and other illnesses, a child's hospitalization might motivate a smoking parent to consider changing smoking behavior. It is unclear if parents would be receptive to smoking-cessation interventions at the time when their child is hospitalized. METHODS: In March 1999, parents of 298 consecutive children admitted to the medical services at Children's Hospital Boston were interviewed to determine the smoking status of household members. Smoking parents were invited to complete a 35-item questionnaire regarding personal smoking history and acceptability of three types of cessation interventions. RESULTS: Sixty-five smoking parents were identified among the 298 admissions; 62 of 65 (95%) participated in the survey. Among respondents, only 15% had ever participated in any smoking-cessation program, and only 31% had ever used a medication to try to quit. Although 78% of parents were willing to speak with a counselor about their smoking while their child was in the hospital, and 74% would enroll in a telephone-based smoking-cessation program, only 26% were interested in a free program requiring travel back to the hospital. All parents believed that pediatricians should offer parental smokers the chance to participate in a smoking-cessation program. CONCLUSIONS: At the time of a child's hospitalization, parents are willing to enroll in smoking interventions that include in-hospital and telephone counseling but not to travel back to the hospital. A child's hospitalization may provide a unique opportunity to enroll parents who smoke into cessation programs.

Adult↗
PubMed2000

No contractile effect for 5-HT1D and 5-HT1F receptor agonists in human and bovine cerebral arteries: similarity with human coronary artery.

1. Using subtype-selective 5-HT1 receptor agonists and/or the 5-HT1 receptor antagonist GR127935, we characterized in vitro the 5-HT receptor that mediates the contraction of human and bovine cerebral arteries. Further, we investigated which sumatriptan-sensitive receptors are present in human coronary artery by reverse-transcriptase polymerase chain reaction (RT-PCR). 2. Agonists with affinity at the 5-HT1B receptor, such as sumatriptan, alniditan and/or IS-159, elicited dose-dependent contraction in both human and bovine cerebral arteries. They behaved as full agonists at the sumatriptan-sensitive 5-HT1 receptors in both species. In contrast, PNU-109291 and LY344864, selective agonists at 5-HT1D and 5-HT1F receptors, respectively, were devoid of any significant vasocontractile activity in cerebral arteries, or did not affect the sumatriptan-induced vasocontraction. The rank order of agonist potency was similar in both species and could be summarized as 5-HT = alniditan > sumatriptan = IS-159 >>> PNU-109291 = LY344864. 3. In bovine cerebral arteries, the 5-HT1 receptor antagonist GR127935 dose-dependently inhibited the vasoconstrictions elicited by both 5-HT and sumatriptan, with respective pA2 values of 8.0 and 8.6. 4. RT-PCR studies in human coronary arteries showed a strong signal for the 5-HT1B receptor while message for the 5-HT1F receptor was weak and less frequently detected. Expression of 5-HT1D receptor mRNA was not detected in any sample. 5. The present results demonstrate that the triptan-induced contraction in brain vessels is mediated exclusively by the 5-HT1B receptor, which is also present in a majority of human coronary arteries. These results suggest that selective 5-HT1D and 5-HT1F receptor agonists might represent new antimigraine drugs devoid of cerebro- and cardiovascular effects.

Animals↗
PubMed1999

Using sector endoluminal ultrasound to identify the normal pancreas when axial computed tomography is falsely positive.

RATIONALE AND OBJECTIVES: Little has been reported on the ability of endoluminal ultrasound (EUS) to identify a normal pancreas after an abnormal axial computed tomogram (CT). Many clinicians still use axial technology, as opposed to helical or spiral CT, which differ in scanning speed. Spiral CT and EUS are considered equal in their ability to diagnose pancreatic tumors. Although this is not the case with axial CT, the complementary role by EUS has not been defined. This study reports on the ability of EUS to identify the "true-negative" pancreas deemed abnormal by axial CT. METHODS: Sixty-five consecutive patients suspected of having a small pancreatic lesion were studied by comparing axial CT and EUS examinations, using each patient as his or her own control. Identification of a normal pancreas was reviewed using surgery, biopsy, and long-term clinical follow-up as the standard of truth. RESULTS: Thirty-three patients were documented as having small pancreatic lesions; the remaining 32 were normal. The sensitivity and specificity, respectively, were 91% and 41% for axial CT and 88% and 88% for EUS. The positive and negative predictive values, respectively, were 61% and 82% for CT and 88% and 88% for EUS. The statistical differences between axial CT and EUS were significant. CONCLUSION: An axial CT positive for a small pancreatic mass requires confirmation with additional imaging before invasive management. The specificity of EUS--twice that of CT--is strong evidence that EUS can fulfill this role. Review of the literature supports the conclusion that EUS should be required in the workup of small pancreatic lesions identified at axial CT.

Chronic Disease↗
PubMed1997

Initial experience with FK506 (tacrolimus) in pediatric renal transplant recipients.

PURPOSE: The efficacy and safety of the new immunosuppressant agent, FK506 (tacrolimus), was assessed in pediatric renal transplant recipients over a mean 12-month follow-up period. METHODS: Twenty pediatric renal transplant recipients received oral FK506 therapy (0.3 mg/kg/d) in combination with azathioprine (1 to 2 mg/kg/d) and low-dose prednisone as primary therapy (n = 11) or were converted from cyclosporine-based therapy (n = 9) for complications including cyclosporine toxicity (n = 2), acute refractory rejection (n = 4), and chronic rejection (n = 3). Patients were then followed-up prospectively to evaluate effectiveness of therapy and complications. RESULTS: In the primary treatment group, 45% of patients had one or more rejection episodes. Two required OKT3 therapy (18%) for persistent rejection, with one (9%) graft loss at 3 months. All other episodes were treated effectively with FK506 dose adjustment and steroid pulses. Patient and graft survival was 100% and 91%, respectively, at 12 months mean follow-up. In the FK506 conversion group, two teenage girls with intractable acne and hirsutism were converted with complete resolution and no change in renal function. Four patients were converted for acute rejection: two who did not respond to steroid pulse and two who did not respond to both steroids and OKT3. All four grafts were salvaged (mean follow-up, 12 months; mean Creatinine [Cr], 1.1). Three patients were converted for biopsy-proven chronic rejection at 3, 10, and 12 years after transplant (mean Cr, 2.4) with two of three of patients stable with functioning grafts at 1 year after conversion. Complications of FK506 therapy included temporary insulin-dependent diabetes mellitus (10%), neurological complications (25%), renal toxicity (15%), and hypertension (85%). There were no cases of gastrointestinal toxicity, hepatic dysfunction, lymphoproliferative disorders, or life threatening viral infection. All symptoms of toxicity responded to dose adjustment. No patient required conversion from FK506 to other agents. CONCLUSION: This early experience indicates that FK506 in combination with low-dose steroids and azathioprine appears to provide safe and effective immunosuppression in the pediatric age group as a primary agent and may salvage grafts in patients with refractory steroid and OKT3 resistant rejection. Graft and patient survival is comparable to that seen with conventional cyclosporine-based immunosuppression.

Adolescent↗
PubMed1996

Pneumococcal polysaccharide vaccine in children with chronic renal disease: a prospective study of antibody response and duration.

We studied the antibody response to pneumococcal serotypes 3 and 14 after pneumococcal polysaccharide vaccine was administered to 41 children with renal disease. One month after vaccination, 76% and 61% of patients achieved at least a twofold titer rise to serotypes 3 and 14, respectively; this finding was comparable to historic control values. One year after vaccination, the majority of patients retained protective antibody levels. Achieving a titer > or = 1.0 microgram/ml IgG at 1 month was highly predictive of retaining a protective antibody level > or = 0.15 microgram/ml at 1 year.

Adolescent↗
PubMed1996

Differential expression of sumatriptan-sensitive 5-hydroxytryptamine receptors in human trigeminal ganglia and cerebral blood vessels.

The efficacy of sumatriptan in migraine relief has been attributed to its interaction with 5-hydroxytryptamine1D (5-HT1D) receptors in cerebral blood vessels and/or on nerve endings of the trigeminovascular system in the dura mater. Using the high sensitivity of polymerase chain reaction (PCR) amplification, we investigated the expression of the sumatriptan-sensitive 5-HT receptors, namely, the 5-HT1D alpha, 5-HT1D beta, and 5-HT1F subtypes in human trigeminal ganglia (10 experiments) and cerebral blood vessels (seven experiments) obtained postmortem. Messages for the 5-HT1D alpha and 5-HT1D beta receptors were expressed in all except one of the 10 trigeminal ganglia studied. Expression of the 5-HT1F receptor was detected by gel electrophoresis of the PCR products in six ganglia and by Southern blot hybridization in two additional cases. In human brain vessels, message for the 5-HT1D beta receptor was present in all samples, whereas specific PCR products corresponding to the 5-HT1D alpha receptor could hardly be detected in only two preparations. PCR products indicative of the 5-HT1F receptor message were detected by gel electrophoresis in three brain vessel preparations and confirmed in the other four by Southern blot hybridization. Restriction mapping and sequence analysis of all PCR products identified the expected human 5-HT receptor DNA sequences. The data confirm that the 5-HT1D beta receptor is the dominant species in human cerebral blood vessels and further show that this receptor and the 5-HT1F are expressed in both neural and vascular tissues. In contrast, the data point to a preferential expression of 5-HT1D alpha receptors in neural versus vascular tissues and strongly reemphasize the need for selective 5-HT1D alpha agonists in the identification of the target tissue(s) for antimigraine drugs. Moreover, the data stress the importance to better understand the role of 5-HT1F receptors in cerebrovascular functions and dural inflammation and further raise interest regarding their possible involvement in migraine therapy.

Adult↗
PubMed1995

Immune response to influenza vaccination in children with renal disease.

Although immunization with influenza vaccine is recommended for children with chronic renal disease and after organ transplantation, the antibody response in these children has not been well described. We studied the response to the 1993-1994 trivalent influenza vaccine in children, aged 1-21 years, with chronic renal failure (n = 15), end-stage renal disease requiring dialysis (n = 10), and post renal transplantation (n = 17). Each group's antibody response was compared with that of a control group (n = 7). No significant differences were found in seroconversion rates, percentage of patients achieving protective hemagglutination-inhibition titers post vaccination or change in geometric mean titers from pre to post vaccination between study groups and controls. These results suggest that pediatric patients with renal disease will respond and therefore will benefit from currently recommended influenza immunization.

Adolescent↗
PubMed1994

Lanthanide particles in the lung of a printer.

Lanthanides were extracted from the lung tissue of a subject with a history of potential exposure to carbon-arc lamp emissions in printing shops. The characterization of inorganic particles was performed by energy dispersive X-ray spectroscopy (EDS) on a transmission electron microscope (TEM) and laser microprobe mass analysis (LAMMA). Both techniques showed the presence of elemental Ce, La and Nd at concentrations higher than the average concentration measured in 41 other workers who had died of cancer at various sites. The lung content of other prismatic and compact particles did not show any statistically significant differences between the case and the control group.

Carcinoma, Squamous Cell↗
PubMed1994

Neisseria sicca peritonitis in a patient maintained on chronic peritoneal dialysis.

Neisseria sicca, previously classified as a "nonpathogenic" organism, has now been recognized as a cause of many infections, including endocarditis and meningitis. However, it has not been reported as a cause of peritonitis. We present a case of documented N. sicca peritonitis immediately following an episode of Staphylococcus aureus peritonitis in a pediatric chronic peritoneal dialysis (CPD) patient. N. sicca should be considered as a possible pathogen in CPD-associated peritonitis.

Anti-Bacterial Agents↗
PubMed1994

Recombinant human growth hormone.

Recombinant human growth hormone was initially used as replacement therapy in children with short stature. As rhGH has become more readily available, it has been tested in a variety of other individuals who have delayed growth. Children with ESRD experience significant problems with delayed growth, thus replacement therapy with rhGH has been used in this population. resulting in improved growth velocity. The clinical significance of improved height may have a positive impact on the psychological well being of these children.

Child↗
PubMed1993

Defective antibody response to Hemophilus influenzae type b immunization in children receiving peritoneal dialysis.

Pediatric end-stage renal disease patients, maintained on chronic peritoneal dialysis (CPD), may have a variety of immunological abnormalities, including hypogammaglobulinemia and poor responses to vaccines. We measured antibody levels to Hemophilus influenzae type b (Hib) in 24 CPD patients. Eight children received primary Hib immunization while undergoing CPD. Of these, 1 of 8 (12%) lacked protective levels of antibody. In another child, who had an initial protective response, antibody levels were undetectable 12 months after immunization. Sixteen of the patients had not been immunized with Hib vaccine because they were more than 5 years old when the vaccine was licensed. In this group, 5 of 16 (31%) lacked protective levels of anti-Hib antibody. Of those available for follow-up, 3 responded normally to Hib vaccine. It is not sufficient to provide childhood immunizations to CPD patients with the assumption that those immunizations will lead to long-lived immunity. Antibody levels should be measured within a month of immunization and at regular intervals thereafter to document immunity.

Adolescent↗
PubMed1992

Ferruginous body counts in sputum as an index of past exposure to mineral fibres.

Previous work by our group among vermiculite miners exposed to fibrous tremolite demonstrated that asbestos body counts in sputum closely reflected intensity and duration of past exposure. In the present project sputum samples from nearly 600 volunteers from 11 cohorts of workers exposed to asbestos and other mineral fibres were found to contain much lower numbers of asbestos bodies than had been observed in vermiculite workers and these counts did not reliably reflect past levels of exposure. No evidence was found that occupational exposure to man-made mineral fibres led to any ferruginous body formation. Asbestos body counts appeared to differentiate between mesothelioma cases and controls and between levels of radiological asbestosis, but in both comparisons, based on small numbers, the power of discrimination was low. Substantial variation was found both in asbestos body and in macrophage counts in daily sampling of vermiculite workers but it was not sufficient to invalidate comparison between groups for epidemiological study. In individual subjects, however, little reliance can be put on results from a single sputum sample, particularly if negative.

Adult↗