Biomedical subjects

J Thompson

Publications and source records attributed to J Thompson.

At least 253 records · Page 14Linked to original sources

PubMed1997

Microembolization during endovascular and conventional aneurysm repair.

PURPOSE: Endovascular aneurysm repair has been advocated as a "minimally invasive" alternative to conventional aneurysm surgery. However, because of manipulation within the aneurysm sac, endovascular techniques may result in massive microembolization. METHODS: In this study lower limb microemboli were quantified in 29 patients undergoing conventional (11 straight and 7 bifurcated grafts) and endovascular aneurysm repair (8 aortoiliac, 1 straight, and 2 bifurcated grafts) by insonation of the superficial femoral artery with a 2 MHz Doppler probe. Emboli were detected as high-intensity, short-duration signals on the background Doppler trace. Differentiation of gaseous emboli from particulate emboli was achieved by calculation of the sample volume length (emboli velocity x duration = sample volume length) for each embolus (N = 4927). Previous experiments had determined that a sample volume length < 1.4 cm represented particulate embolization. RESULTS: The number of gaseous, particulate, and total emboli were significantly greater in the endovascular group compared with the conventional group (p < 0.05). CONCLUSIONS: These data demonstrate that peripheral microembolization is significantly higher during endovascular aneurysm repair than during conventional surgery. Methods to reduce embolization must be developed before endovascular aortic surgery is widely adopted.

Aged↗

PubMed1997

RT-PCR investigation of fibronectin mRNA isoforms in malignant, normal and reactive oral mucosa.

This study aimed to establish patterns of cellular fibronectin mRNA splice variants in normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, and focal reactive overgrowths of oral mucosa. Particular emphasis was placed on evaluation of either the EDA or EDB domains as markers of malignancy. Total RNA was extracted from normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, reactive epulides, fibroepithelial polyps and denture-related hyperplasia. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to identify different fibronectin transcripts at three splice sites (EDA, EDB and IIICS). All the tissues investigated produced EDA+, EDA-, EDB+ and EDB- splice variants, and this study did not support RT-PCR-based detection of either EDA or EDB domains as markers of malignancy in oral tissues. Variations in IIICS splice patterns were observed, although these were not specific to any lesion group. In particular, there were differences in either the inclusion or omission of the domain coding for the CS-5 binding site for alpha 4 beta 1 integrin, whereas the CS-1 binding site for alpha 4 beta 1 integrin was typically present when additional domains were included at the IIICS splice site. In conclusion, complex patterns of fibronectin splice variant transcripts exist in normal and pathological oral mucosa. This may reflect the multiple biological functions identified for fibronectin proteins, although the significance of different specific fibronectin splice variants has yet to be fully elucidated.

Alternative Splicing↗

PubMed1997

Counterflow centrifugal elutriation as a method of T cell depletion may cause loss of immature CD34+ cells.

Counterflow centrifugal elutriation (CCE) is capable of separating cells on the basis of size. CCE has been used successfully to deplete allogeneic bone marrow (BM) grafts of T lymphocytes to decrease the risk of acute graft-versus-host disease. Previous studies have shown that more immature CD34+ cells in human BM tend to be smaller than more mature CD34+ cells. Human BM was subjected to CCE with the 4 ml standard chamber at constant rotor speed (2300 r.p.m.) and increasing flow-rate (14-23 ml/min, rotor-off). The eleven fractions collected were assayed for CD34+ and CD3+ cells, and for CFU-GM, HPP-CFC and long-term culture initiating cells (LTC-IC). The CD3+ T cells were enriched in the early (small-cell) fractions 14-17 ml/min. CD34+ cells were enriched in fractions 17-21 ml/min, and CFU-GM were concentrated in the same fractions. HPP-CFC and LTC-IC showed nearly identical CCE profiles, with enrichment in fractions 16-18 ml/min. When fraction < or = 17 ml/min was chosen as cut-off, the small-cell fraction contained 94.0% of all CD3+ cells, 44.4% of total cells, 33.2% of CD34+ cells and 34.7% of CFU-GM; however, 67.6% of HPP-CFC and 72.4% of LTC-IC were recovered in this small-cell fraction. These data suggest that T cell depletion through CCE as used by us, while losing only minor proportions of CD34+ cells and CFU-GM, carries the risk of losing the majority of more immature progenitor cells. This may lead to an increased risk of graft failure, in particular in HLA-mismatched transplants.

Antigens, CD34↗

PubMed1997

Memories for the Marchioness.

We examined the accounts of 27 survivors of the Marchioness ferry sinking, using cross-validation of accounts to search for instances of motivated forgetting. In order to identify objective items that could be validated, we focused the analysis on subjects' statements of whom they were with at various stages of the disaster. We compared these findings with an informal recall of a non-traumatic event after an interval of a few days. The main finding was that recall was reasonably good for both traumatic and non-traumatic events. Specifically, in the Marchioness sample, among those 86 statements that could have been confirmed in the accounts of other informants, 74 were in fact confirmed. Of the remaining 12 unconfirmed statements, only one involved a contradiction. We conclude that for a disaster of this kind, and with this particular sample of individuals, motivated forgetting was extremely rare.

Amnesia↗

PubMed1997

Epidemiology and clinical impact of parainfluenza virus infections in otherwise healthy infants and young children < 5 years old.

Over a 20-year period in a population of otherwise healthy children, respiratory viruses have been cultured from nasal wash specimens from each child with a clinically significant respiratory illness. Since efforts are underway to develop vaccines for prevention of illness due to parainfluenza virus (PIV) type 3, the epidemiologic characteristics of PIVs were reviewed, and the population size necessary to demonstrate vaccine efficacy was estimated. A population of 1429 children was followed through early childhood. PIVs were isolated from 286 samples, 17.4% of positive viral cultures. PIV-3 was the most common: 10% of the children had at least one symptomatic, culture-proven PIV-3 infection. PIV-3 was endemic during the study period, while the other two PIVs, PIV-1 and -2, caused biennial flu epidemics. Only four PIV-related hospitalizations were seen. The efficacy of a PIV-3 vaccine could be demonstrated in a trial of 600 carefully monitored children vaccinated by 3 months and followed to 15 months of age.

Child, Preschool↗

PubMed1997

Evaluation of two live, cold-passaged, temperature-sensitive respiratory syncytial virus vaccines in chimpanzees and in human adults, infants, and children.

Two live-attenuated, cold-passaged (cp), temperature-sensitive (ts) candidate vaccines, designated cpts530/1009 and cpts248/955, were attenuated, genetically stable, and immunogenic in chimpanzees and were highly attenuated for human adults. In respiratory syncytial virus (RSV)-seropositive children, cpts530/1009 was more restricted in replication than cpts248/955. In seronegative children, 10(4) pfu of cpts248/955 was insufficiently attenuated, and a high titer of vaccine virus was shed (mean peak titer, 10(4.4) pfu/mL), whereas 10(4) pfu of cpts530/1009 was relatively attenuated and restricted in replication (mean peak titer, 10(2.0) pfu/mL). At a dose of 10(5) pfu, cpts530/1009 was immunogenic in seronegative children (geometric mean titer of RSV neutralizing antibodies, 1:724). Transmission of either vaccine to seronegative placebo recipients occurred at a frequency of 20%-25%. Of importance, vaccine viruses recovered from chimpanzees and humans were ts. In contrast to previous studies, this study indicates that live attenuated RSV vaccines that are immunogenic and phenotypically stable can be developed. Additional studies are being conducted to identify a live RSV vaccine that is slightly more attenuated and less transmissible than cpts530/1009.

Adolescent↗

PubMed1997

Lineage commitment of HLA-DR/CD38-defined progenitor cell subpopulations in bone marrow and mobilized peripheral blood assessed by four-color immunofluorescence.

We used four-color fluorescence analysis to compare lineage antigen expression in relationship to CD38 and HLA-DR on CD34+ progenitor cells in adult human bone marrow and mobilized peripheral blood. Each of four progenitor cell subpopulations defined by HLA-DR and CD38 intensity (CD38-/HLA-DR-, CD38-/HLA-DR+, CD38+/HLA-DR+, and CD38+/HLA-DR-) were present in both progenitor cell sources in similar ratios. The most prevalent subpopulation consisted of cells that expressed both CD38 and HLA-DR. Virtually all progenitor cells that lacked CD38 also lacked lineage antigens regardless of their HLA-DR expression. In contrast, the majority of the cells within both CD38+ progenitor cell subpopulations possessed either lineage antigens or the proliferation-associated antigen, CD71. Furthermore, CD71 was expressed on three times the number of CD38+/HLA-DR- cells when compared with the CD38-/HLA-DR- subpopulation. Within CD34+ progenitor cell subpopulations defined by the expression of CD38 and HLA-DR, the CD38+/HLA-DR- component appears to be the most mature, based on the expression of CD71 and various lineage-associated antigens, including representative markers characterizing early lymphoid, myeloid, and erythroid precursors. Thus, selection of the most immature CD34+ progenitor cells based solely on the lack of HLA-DR expression results in isolation of two distinct cell populations with markedly different maturation status and resultant growth characteristics.

ADP-ribosyl Cyclase↗

PubMed1997

Efficacy of oral irinotecan against neuroblastoma xenografts.

The efficacy of the topoisomerase I inhibitor, 7-ethyl-10-(4-[1-piperidino]-1-piperidino)-carbonyloxy-camptotheci n (irinotecan, CPT-11), administered by oral gavage has been examined against a panel of six independently derived neuroblastoma xenografts. Irinotecan was administered either daily for 5 days on 12 consecutive weeks ¿(d x 5)12¿ or for 5 days on two consecutive weeks repeated every 21 days for 4 cycles ¿[(d x 5)2]4¿. Given on the (d x 5)12 schedule the maximum tolerated dose (MTD) was 50 mg/kg. For intermittent scheduling ¿[(d x 5)2]4¿, the MTD was 75 mg/kg, resulting in the same total dose being administered (3 g/kg) over the period of treatment. At the MTD for the 12 consecutive week schedule there were two of 42 toxicity related deaths, whereas intermittent scheduling at the MTD resulted in none of 42 deaths. The intermittent schedule ¿[(d x 5)2]4¿ was less toxic than therapy given (d x 5)12, as at the end of treatment mice weighed 92 +/- 4% (SD; n = 6 experiments) and 81 +/- 4% (SD; n = 6 experiments) of their body weight at the start of therapy, respectively. The latter schedule was associated with loose feces starting around week 8 of therapy, broken teeth and a high incidence of swelling of the orbital conjunctiva that developed late in the course of therapy. Given (d x 5)12, irinotecan caused complete regressions of all six neuroblastoma xenograft lines. Because mice tolerate significantly greater systemic exposure to SN-38 lactone than do patients (as determined by plasma AUC at the respective MTD), we evaluated the intermittent schedule of administration, reducing the dose/administration to determine the lowest dose levels that produced objective regressions of these neuroblastoma xenografts and determined the daily systemic exposure associated with these dose levels. In four lines examined objective responses were obtained at dose levels of 12.5 or 6.25 mg/kg. The daily plasma AUC exposures associated with minimum dose achieving response in NB1691 (12.5 mg/kg), NB1643 (6.25 mg/kg) and NBEB (12.5 mg/kg) for irinotecan lactone were 219, 152 and 653 ng-h/ml, respectively; and for SN-38 lactone were 704, 418 and 987 ng-h/ml, respectively. These results indicate that childhood neuroblastoma xenografts are highly sensitive to irinotecan given by oral administration and therapeutic activity is similar to i.v. irinotecan administered on similar schedules.

Administration, Oral↗

PubMed1997

The DSM-IV Outline for Cultural Formulation: a critical demonstration with American Indian children.

OBJECTIVE: The publication of DSM-IV is notable for the improved coverage of cultural issues in the diagnosis of mental disorders. In particular, Appendix I of DSM-IV includes an "Outline for Cultural Formulation" (Outline) which assists the clinician in evaluating the impact of an individual's cultural context on diagnosis and treatment. However, the capacity of the Outline to facilitate the development of comprehensive cultural formulations for children and adolescents has not been established. In this article the use of the Outline with American Indian children is reviewed critically. METHOD: Based on the Outline, cultural case formulations for four American Indian children were developed and their comprehensiveness was assessed. RESULTS: Applied to the case material, the Outline provided a clear template for the development of cultural formulations. Nonetheless, several gaps in the material required by the Outline were identified, particularly in the areas concerning cultural identity and cultural elements of the therapeutic relationship. CONCLUSIONS: Clinicians working with children should recognize the strengths as well as the limitations of the Outline and expand their cultural descriptions accordingly. Several additions to the text of the Outline that will facilitate the development of comprehensive cultural formulations specific to children and adolescents are proposed.

Case Management↗

PubMed1997

Pediatric aerodigestive foreign body injuries are complications related to timeliness of diagnosis.

Foreign body (FB) injury from aspiration or ingestion is a common pediatric health problem. Diagnosis relies on clinical judgment plus medical history, physical examination, and radiographic evaluation. A multi-institutional review of 1269 FB events revealed that 85% were correctly diagnosed following a single physician encounter. However, 15% of the children had an elusive diagnosis (>1 week), despite previous evaluation. Delays in diagnosis were seven times more likely to occur in aspirations than in ingestions. Secondary injuries (e.g., pneumonia and atelectasis) occurred in 13% of airway FBs but in only 1.7% of esophageal FBs. Plain radiographs were used in 82% of children, and special studies (e.g., fluoroscopy) in only 7%. We conclude that diagnosis of FB injury in children is frequently achieved at the initial evaluation but that continued surveillance by follow-up visits to health care facilities from parents and other caretakers is important, to reduce pulmonary injuries.

Adolescent↗

PubMed1997

D2 dopamine receptor gene (DRD2) Taq1 A polymorphism: reduced dopamine D2 receptor binding in the human striatum associated with the A1 allele.

The relationship between a dopamine D2 receptor genetic polymorphism at the Taq1 A locus and the level of D2 receptor binding was investigated in normal, middle aged to elderly subjects with no psychiatric or neurological disorders. D2 receptor binding was measured by autoradiography in the caudate, putamen and nucleus accumbens, using the specific D2 receptor ligand [3H]-raclopride. In a sample of 44 individuals, only one was homozygous for the A1 allele, 25 were homozygous for A2 and 18 were heterozygotes. The presence of one or two A1 alleles was associated with reduced D2 receptor binding in all areas of the striatum, reaching statistical significance in the ventral caudate and putamen (p = 0.01 and p = 0.044, respectively). This reduction was more marked in males than females, particularly in the putamen. A genetic predisposition to lower D2 receptor expression may increase susceptibility to neuroleptic medication or clinical symptoms that are associated with diseases involving dopaminergic pathology.

Aged↗

PubMed1997

Radiation-induced chromatid breaks and DNA repair in blood lymphocytes of patients with dysplastic nevi and/or cutaneous melanoma.

Each chromatid contains a single continuous molecule of double-stranded DNA, so chromatid breaks represent unrepaired DNA double-strand breaks. Frequencies of chromatid breaks after G2 phase x-irradiation were determined in phytohemagglutinin-stimulated blood lymphocytes from normal subjects and from four categories of patients with dysplastic nevi with or without cutaneous melanoma or with melanoma alone. Some cells were treated with an inhibitor of DNA repair replication to determine enzymatic incision activity at damaged sites after exposure to x-rays, UVC, or fluorescent light. Whereas one of 16 normal controls had deficient DNA repair, all 17 patients from families with hereditary dysplastic nevi with or without melanoma (category I) had a deficiency in repair of radiation-induced DNA damage, manifested as an abnormally high frequency of chromatid breaks after x-irradiation or a reduced capacity to incise the damaged sites after UV exposure. Four of 11 patients with sporadic dysplastic nevi alone (category II) and eight of 12 with sporadic dysplastic nevi and melanoma (category III) showed deficient DNA repair after x-irradiation. One of two patients with sporadic melanoma and no dysplastic nevi (category IV) was also deficient in repair of x-ray-induced damage. Deficient DNA repair thus appears to be associated with hereditary dysplastic nevi with or without melanoma. It also characterizes some patients with sporadic dysplastic nevi or melanoma.

Adolescent↗

PubMed1997

The effect of laryngeal mask airway insertion on the position of the internal jugular vein.

A high-quality ultrasound system (Dyasonics Prisma) was used to study the effect of laryngeal mask airway insertion and cuff inflation on the position and relations of the internal jugular vein in eight healthy young patients undergoing elective surgery. On insertion of the laryngeal mask, with the cuff pre-inflated with 10 ml of air, some minor movement was discernible in the larynx. Neither the larynx nor surrounding structures changed significantly in position. However, on full inflation of the laryngeal mask cuff there was a more noticeable movement of the larynx, which visibly distended in an anterior direction. The mean anterior displacement was 0.8 cm (range 0.6-1.1 cm). There was no significant lateral displacement of the carotid artery or internal jugular vein and there was no significant compression of these structures. We conclude that in the presence of a laryngeal mask airway fixed landmarks such as the sternal notch and angle of the jaw should be used to identify the likely position of the internal jugular vein. Difficulty in cannulation may be experienced if the mobile laryngeal structures are used as landmarks.

Adolescent↗

PubMed1997

Collaborating for international research development in Malawi, Africa.

PURPOSE: To describe a collaborative research effort by a U.S. school of nursing, an African school of nursing, and the Malawian Ministry of Health. Providing assistance to women leaders in Malawi to develop and conduct research to improve the health of women and infants in villages is necessary. SCOPE: This 5-year project, 1990-1995, included organizing a workshop on the research process, developing and testing pilot projects, developing and conducting two full-scale studies, and disseminating findings. RESULTS: Two full-scale studies, one examining maternal mortality and one examining the effects of teen pregnancy, were completed with important health policy implications for Malawi. CONCLUSIONS: Successful international collaborative research yields increased knowledge for all participants and important health information. International research requires continuous communication, people skilled in group work, sensitivity to cultural differences, patience, persistence, and commitment.

Cooperative Behavior↗

PubMed1997

Displaying electroencephalographic dipole sources on magnetic resonance images.

A simple, inexpensive method of displaying electroencephalographic (EEG) dipole sources on magnetic resonance images (MRIs) is presented. It consists of measuring the head according to the 10-20 system but instead of placing electrodes, benzonatate capsules (Tessalon Perles) (100 mg) are affixed to the patient's scalp. MRI is obtained with the capsules in place. In addition to the routine images, thin-section (1.0-1.3-mm) scans in a three-dimensional volume are obtained and the coordinates for each electrode position ascertained. The capsules are then replaced by electrodes and a waking and sleep recording is performed with a digital EEG instrument. Phenomena of interest are then averaged and interfaced with a source analysis program. The three-dimensional electrode coordinates are placed in a file and used to establish the electrode cloud on the basis of which source analysis proceeds. The three-dimensional source locations are then superimposed on the MRIs. The method is useful in the workup of epilepsy patients, by relating focal epileptogenic activity to definable lesions, and it also allows more precise localization of normal EEG phenomena.

Adolescent↗

PubMed1997

6-phospho-alpha-D-glucosidase from Fusobacterium mortiferum: cloning, expression, and assignment to family 4 of the glycosylhydrolases.

The Fusobacterium mortiferum malH gene, encoding 6-phospho-alpha-glucosidase (maltose 6-phosphate hydrolase; EC 3.2.1.122), has been isolated, characterized, and expressed in Escherichia coli. The relative molecular weight of the polypeptide encoded by malH (441 residues; Mr of 49,718) was in agreement with the estimated value (approximately 49,000) obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for the enzyme purified from F. mortiferum. The N-terminal sequence of the MalH protein obtained by Edman degradation corresponded to the first 32 amino acids deduced from the malH sequence. The enzyme produced by the strain carrying the cloned malH gene cleaved [U-14C]maltose 6-phosphate to glucose 6-phosphate (Glc6P) and glucose. The substrate analogs p-nitrophenyl-alpha-D-glucopyranoside 6-phosphate (pNP alphaGlc6P) and 4-methylumbelliferyl-alpha-D-glucopyranoside 6-phosphate (4MU alphaGlc6P) were hydrolyzed to yield Glc6P and the yellow p-nitrophenolate and fluorescent 4-methylumbelliferyl aglycons, respectively. The 6-phospho-alpha-glucosidase expressed in E. coli (like the enzyme purified from F. mortiferum) required Fe2+, Mn2+, Co2+, or Ni2+ for activity and was inhibited in air. Synthesis of maltose 6-phosphate hydrolase from the cloned malH gene in E. coli was modulated by addition of various sugars to the growth medium. Computer-based analyses of MalH and its homologs revealed that the phospho-alpha-glucosidase from F. mortiferum belongs to the seven-member family 4 of the glycosylhydrolase superfamily. The cloned 2.2-kb Sau3AI DNA fragment from F. mortiferum contained a second partial open reading frame of 83 residues (designated malB) that was located immediately upstream of malH. The high degree of sequence identity of MalB with IIB(Glc)-like proteins of the phosphoenol pyruvate dependent:sugar phosphotransferase system suggests participation of MalB in translocation of maltose and related alpha-glucosides in F. mortiferum.

Amino Acid Sequence↗

PubMed1997

Phospho-beta-glucosidase from Fusobacterium mortiferum: purification, cloning, and inactivation by 6-phosphoglucono-delta-lactone.

6-Phosphoryl-beta-D-glucopyranosyl:6-phosphoglucohydrolase (P-beta-glucosidase, EC 3.2.1.86) has been purified from Fusobacterium mortiferum. Assays for enzyme activity and results from Western immunoblots showed that P-beta-glucosidase (Mr, 53,000; pI, 4.5) was induced by growth of F. mortiferum on beta-glucosides. The novel chromogenic and fluorogenic substrates, p-nitrophenyl-beta-D-glucopyranoside-6-phosphate (pNPbetaGlc6P) and 4-methylumbelliferyl-beta-D-glucopyranoside-6-phosphate (4MUbetaGlc6P), respectively, were used for the assay of P-beta-glucosidase activity. The enzyme hydrolyzed several P-beta-glucosides, including the isomeric disaccharide phosphates cellobiose-6-phosphate, gentiobiose-6-phosphate, sophorose-6-phosphate, and laminaribiose-6-phosphate, to yield glucose-6-phosphate and appropriate aglycons. The kinetic parameters for each substrate are reported. P-beta-glucosidase from F. mortiferum was inactivated by 6-phosphoglucono-delta-lactone (P-glucono-delta-lactone) derived via oxidation of glucose 6-phosphate. The pbgA gene that encodes P-beta-glucosidase from F. mortiferum has been cloned and sequenced. The first 42 residues deduced from the nucleotide sequence matched those determined for the N terminus by automated Edman degradation of the purified enzyme. From the predicted sequence of 466 amino acids, two catalytically important glutamyl residues have been identified. Comparative alignment of the amino acid sequences of P-beta-glucosidase from Escherichia coli and F. mortiferum indicates potential binding sites for the inhibitory P-glucono-delta-lactone to the enzyme from F. mortiferum.

Amino Acid Sequence↗

PubMed1997

Effect of rhGH and rhIGF-I treatment on protein utilization in elderly women.

To assess the effect of recombinant human growth hormone (rhGH) and recombinant human insulin-like growth factor I (rhIGF-I) on protein utilization, 14 women, age 66-82 yr, were invited to participate in studies of nitrogen balance (n = 14), whole body protein turnover (n = 14), and muscle protein synthesis (n = 8). They were studied both 1 wk before and during the last week of a 1-mo regimen, to which they had been randomly assigned, of either 0.025 mg rhGH/kg once daily or rhIGF-I at 0.015 (low), 0.03 (mid), or 0.06 (high) mg/kg twice daily. Nitrogen balance increased significantly after 1 wk of treatment in all groups (P < 0.05). After 1 mo, the magnitude of this effect had diminished by 50% in the rhGH group but remained elevated throughout the treatment period with all doses of rhIGF-I. Both protein synthesis and breakdown, measured by a primed constant infusion of [15N]glycine, were significantly increased with rhGH (9% and 8%, respectively), low-dose rhIGF-I (4.5% and 4%), and high-dose rhIGF-I (18% and 17%). Net synthesis was significantly increased with rhGH (48%) and high- and mid-dose rhIGF-I (27% and 196%, respectively). Muscle protein synthesis as measured by incorporation of [1-13C]leucine increased significantly with rhGH (50%) and the mid (67%) and high (57%) doses of rhIGF-I. These data show that whole body and muscle protein synthesis are responsive to growth factor stimulation in elderly women.

Aged↗