Biomedical subjects
Publications and source records attributed to B Jones.
Transhiatal herniation of colon is uncommon after transhiatal esophagectomy. Two patients with this complication are presented. Presenting symptoms vary depending on the size and contents of the hernia. Patients may be asymptomatic. The diagnosis is suggested by plain chest radiography, and treatment, in symptomatic patients, is surgical reduction of the hernia via a laparotomy.
Immune activation is mediated by a specific interaction between the T-cell receptor (TCR) and an antigenic peptide bound to the major histocompatibility complex (MHC). T-cell activation can also be stimulated by superantigens which bind to germline-encoded variable domain sequences of certain TCR beta-chains. We have used a surface plasmon resonance biosensor to characterize the molecular interactions between a class II-restricted alphabeta TCR and its superantigen and MHC/peptide ligands. The extracellular domains of the murine D10 TCR (Valpha2, Vbeta8.2) were expressed in insect cells and secreted as a disulfide-linked heterodimer. In the absence of MHC class II, purified soluble D10 TCR bound to Staphylococcus aureus enterotoxin C2 with an association rate of 1.69+/-0.12 x 10(4)M(-1) sec(-1) and a dissociation rate of 1.9+/-0.47 x 10(-2) sec(-1), giving a dissociation constant of 1.1 microM. Binding of the TCR to S. aureus enterotoxin B was barely detectable and could not be measured accurately due to the rapid dissociation rate. Soluble D10 TCR also bound to a soluble murine MHC class II I-A(k) molecule containing a fused antigenic conalbumin peptide and complementary leucine zipper sequences to facilitate efficient chain pairing. The purified I A(k) chimera specifically stimulated proliferation of the D10 T-cell clone, and bound to immobilized soluble D10 TCR with an association rate of 1.07+/-0.19 x 10(4)M(-1)sec(-1) and a dissociation rate of 2.2+/-0.65 x 10(-2) sec(-1), giving a dissociation constant of 2.1 microM.
BACKGROUND/AIMS: In the majority of cases of fulminant "viral" hepatitis in Australia, no known aetiological agent can be isolated. We have examined the possible role of the recently discovered hepatitis G virus (HGV) in such cases. METHODS: An HGV specific reverse transcription polymerase chain reaction (RT-PCR) was performed on pre- and post-liver transplant serum from 14 patients who were referred for transplantation at our unit between 1989 and 1995 for unexplained fulminant hepatic failure. Eleven patients successfully underwent transplantation and three died while waiting for a suitable donor organ. Hepatitis viruses A-E were excluded by standard serological and PCR based testing. HGV RT-PCR was also performed on 21 other, randomly selected, liver transplant recipients ("controls"). RESULTS: The 14 fulminant cases were HGV RT-PCR negative prior to transplantation while five of 21 controls were positive. Post-transplant, eight of the 11 fulminant patients were found to be HGV RT-PCR positive and the same five controls remained HGV RT-PCR positive. In three of the eight fulminant patients the HGV infection resolved. CONCLUSIONS: Our data indicate that HGV infection is unlikely to be responsible for fulminant hepatitis and that it is probably acquired from blood and/or blood products during the transplantation process. Furthermore, long-term carriage of HGV post-transplant is not associated with clinically apparent liver disease.
Difficulties in creating vascular access in patients on hemodialysis are encountered in most dialysis centers. This is usually due to a lack of suitable peripheral vessels due to previous access surgery in patients on long-term hemodialysis, but also may be seen in some patients de novo, particularly diabetics and patients with peripheral vascular disease. Surgical techniques used to overcome this problem vary depending on patient characteristics and, to a certain extent, on local expertise/preference. We report our experience of using silicon dual-lumen hemodialysis catheters over a 3-year period; during this time, 54 catheters were inserted into 32 hemodialysis patients. The indication for this procedure in 52 catheters (31 patients) was either exhausted vascular access or obvious difficulty identifying a suitable peripheral blood vessel. Of the catheters inserted, 20 were placed into subclavian veins by primary insertion (ie, patients did not have existing subclavian catheter); 34 were replaced over a guidewire (a procedure used to allow technique salvage). The catheter survival rate was 72.7% at 90 days and 48.7% at 1 year. Corresponding rates at 90 days and 1 year for technique survival were 93.3% and 81.8%, respectively. The mean catheter and technique survival was 387 (95% confidence intervals [CIs], 273, 502) and 844 (95% CIs, 684, 1,005) days, respectively. Poor flow accounted for 70.4% of catheter failures and, despite 18 episodes of catheter-related sepsis, no catheters were lost due to infection. Factors identified as leading to reduced catheter survival were left-sided placement and catheter tip placement in the superior vena cava (as opposed to right atrial placement). We did not observe poorer survival or increased sepsis in catheters replaced over a guidewire, and would advocate this technique as a means of salvage in this group of patients.
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Twenty-one patients with recurrent intracranial gliomas were retreated by external beam radiotherapy between 1987 and 1995. Twenty patients received cytotoxic chemotherapy involving CCNU as part of their retreatment. Only five of the 21 patients had received chemotherapy in combination with the initial external beam radiotherapy (RT) prior to recurrence. The different histological groups were analysed and the patients divided into two groups; group I (Grade I and II gliomas) and group II (Grade III, IV and glioblastoma). The overall median survival for all patients was 59 months, with a median survival of 22 months after recurrence. For group I and group II patients, the median survival was 26 months and 13 months after recurrence respectively. It was concluded that some highly selected patients with intracranial gliomas can be retreated safely by carefully planned external beam RT given to a relatively low dose in order to palliate neurological dysfunction and the symptoms of raised intracranial pressure, and to reduce steroid dependency. The results strongly suggest that recovery does occur after initial RT. Retreatment may possibly improve survival in a small proportion of patients. Further studies, including randomized trial designs, quality of life assessment, and neurological symptoms indices, would be required to determine the quantitative benefit of any such treatment policy. The objectives of this study were to determine whether patients received any benefit, such as symptom relief and the allowance of steroid withdrawal, after retreatment, and whether long term survival could be achieved.
A non-smoking Asian woman with previously treated pulmonary tuberculosis presented with a recent onset unproductive cough and cavitating mass lesion on her chest X-ray which rapidly developed into a large tuberculous cavity after bronchoscopy. Acid-fast bacilli were isolated from the cavity and she responded very rapidly to standard anti-tuberculous chemotherapy. This unusual condition must be considered in patients who deteriorate after bronchoscopy.
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What are the influences behind falling enrolments into professional nursing pre-service programs and how can the trend be reversed? Bronwyn Jones looks at the issue.
We report the isolation by differential display of a novel tomato ethylene-responsive cDNA, designated ER5. RT-PCR analysis of ER5 expression revealed an early (15 min) and transient induction by ethylene in tomato fruit, leaves and roots. ER5 mRNA accumulated during 2 h of ethylene treatment and thereafter underwent a dramatic decline leading to undetectable expression after 5 h of treatment. The full-length cDNA clone of 748 bp was obtained and DNA sequence analysis showed strong homologies to members of the atypical hydrophobic group of the LEA protein family. The predicted amino acid sequence shows 67%, 64%, 64%, and 61% sequence identity with the tomato Lemmi9, soybean D95-4, cotton Lea14-A, and resurrection plant pcC27-45 gene products, respectively. As with the other members of this group, ER5 encodes a predominantly hydrophobic protein. Prolonged drought stress stimulates ER5 expression in leaves and roots, while ABA induction of this ethylene-responsive clone is confined to the leaves. The use of 1-MCP, an inhibitor of ethylene action, indicates that the drought induction of ER5 is ethylene-mediated in tomato roots. Finally, wounding stimulates ER5 mRNA accumulation in leaves and roots. Among the Lea gene family this novel clone is the first to display an ethylene-regulated expression.
OBJECTIVE: In elderly patients there are few data on the efficacy and safety of pituitary surgery and radiotherapy (DXT). The aim of the present study was to assess the mode of presentation, treatment and outcome of patients > 64 years with a pituitary tumour presenting to a regional neuroendocrine service. DESIGN: A retrospective case note review of all patients with a pituitary tumour, from 1986 to 1993, was performed with DXT information from computerized records. PATIENTS: Forty-four patients were identified: median age 70 (65-83) years; 25 males; followed for a mean of 34 (range 0-84) months. RESULTS: The commonest presenting symptom was with visual disturbance (24 patients) with a further 9 with asymptomatic visual field defects. Five patients had acromegaly and two prolactinoma. Thirty-two patients underwent transsphenoidal surgery (TSS) (with post-operative DXT in 14 cases) and 6 craniotomy. Two patients had DXT as the primary procedure and four were observed. Visual fields improved in 21 of 29 patients. Perioperative complications occurred significantly more often after craniotomy (5/6) than after TSS (6/32) (P < 0.01). Eight patients died during the follow-up period (three deaths tumour related; one death followed DXT). CONCLUSIONS: Pituitary adenoma is a remediable cause of visual disturbance in the elderly. Most tumours were non-functioning. Age alone is not a contraindication to active treatment particularly with transsphenoidal surgery and radiotherapy.
BACKGROUND: Human T-cell lymphoma/leukemia viruses types I and II (HTLV-I and HTLV-II) are related exogenous human retroviruses. The former is definitely pathogenic while disease association with the latter is unclear. There are two subtypes of HTLV-II, A and B. Currently, enzyme-linked immunosorbent assays (ELISAs) based on HTLV-I antigens are used to screen for the presence of HTLV-I and -II antibodies. Confirmation and subtyping are accomplished by Western blot (WB) or ELISAs based on HTLV-I whole viral antigens and/or HTLV-I and HTLV-IIA peptides. The sensitivity and specificity of these serologic assays were compared to those of HTLV-I and-II-specific polymerase chain reaction (PCR) assays in tests on samples from Indians from South America in whom the HTLV-IIB subtype is endemic. STUDY DESIGN AND METHODS: Sera from 246 Gran Chaco Indians were evaluated for HTLV antibodies with the use of four ELISAs (Retrotek HTLV-I; Cambridge Biotech rgp21 enhanced HTLV-I/II; Vironostika HTLV-I/II; and Select HTLV-I/II), and a WB assay. Peripheral blood leukocyte DNA from each Indian was analyzed for HTLV-I or HTLV-II pol DNA via PCR. Fifteen of the PCR-positive samples were further subtyped via cloning and sequencing and/or oligomer restriction. RESULTS: Ninety-seven samples (39%) were positive for HTLV-II by serologic and/or PCR assays. All 15 positive DNA samples that were further analyzed were of the HTLV-IIB subtype and were clustered as a highly conserved phylogenetic group. Comparative analyses indicate that the sensitivity and specificity of the various assays were: PCR, 97 and 100 percent; Retrotek, 70 and 91 percent; Cambridge Biotech, 74 and 96 percent; Vironostika, 73 and 99 percent; Select 72 and 98 percent; and WB, 70 and 100 percent. CONCLUSION: The sensitivities of the tested HTLV serologic assays were comparable. However, the specificity of the Retrotek ELISA was significantly lower than that of the others. When positive, the subtyping assays were very specific. However, PCR assays would seem preferable or to be a necessary adjunct for the sensitive detection of HTLV-IIB infection.
During the completion of an interpretive evaluation project, differences in rates of dying patients using hospice services between nursing homes were examined. Rates were found to vary from 2% to 39% in 23 nursing homes owned by one company. Twenty of the 23 administrators responded to a survey regarding attitudes toward hospice care in the nursing home. Nursing homes with administrators most sympathetic to hospice care had rates three times higher than nursing homes with administrators least sympathetic. Specific concerns were discussed in interviews with four of the least sympathetic administrators. The findings are congruent with program implementation theory which describes the discretionary power of local administrators to limit access to new programs that they find problematic.
PURPOSE: The authors sought to determine if the right ventricular ejection fraction (RVEF), as measured by xenon ventriculography, is depressed in patients with pulmonary emboli. The authors also sought to correlate any decrement in RVEF with the extent of lung perfusion defects. MATERIALS AND METHODS: The authors identified all patients who had lung ventilation-perfusion (V/Q) scans between January 1994 and December 1996, that were interpreted as high probability for pulmonary embolism. From these patients, the authors selected those who had undergone concurrent xenon ventriculography (XV) (n = 23), and then reprocessed the initial ventriculography data for confirmation. The authors also reviewed original V/Q scans, chest radiographs, and clinical data. A control group was drawn from patients with normal V/Q scans who had undergone XV. RESULTS: Fifteen patients (65%) with high probability V/Q scans had an abnormally low RVEF (< .32). Patients with high probability V/Q scans also had a significantly lower mean RVEF (0.28 +/- .08) than patients with normal V/Q scans (.39 +/- .08 SD). The degree of RVEF decline correlated poorly with the number of segmental perfusion defects (r = -.39). CONCLUSIONS: RVEF is often depressed in patients with high probability V/Q scans. XV can identify these patients, while routine lung V/Q scans cannot.
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The effects of 14-day use of either a chlorhexidine/xylitol or a xylitol chewing gum on salivary levels of mutans streptococci, lactobacilli, and yeasts were determined for 53 subjects (mean age 79.49 +/- 7.7 years) participating in this randomised, double-blind, placebo-controlled trial. Salivary flow rates and enamel staining were measured and the attitudes of the subjects to gum chewing were evaluated by the use of structured questionnaires. The chlorhexidine/xylitol gum significantly reduced the salivary levels of mutans streptococci (p < 0.0001) lactobacilli (p < 0.05) and yeasts (p < 0.05) while the xylitol placebo gum produced significant reductions in mutans streptococci (p < 0.01) only. The study population found chewing gum twice per day for 10 min an acceptable method of receiving medication and improving oral health. Prior to gum use participants recognised persistent symptoms of dry mouth and their subjective evaluation of dry mouth was significantly (p < 0.001) related to the number of prescribed medications with xerostomic side-effects. The desire to continue gum use was significantly related to the subjects' evaluation of their oral dryness at baseline and to their perceived oral health gain from gum usage. Only those participants with stained enamel at baseline exhibited increased enamel staining following chlorhexidine/xylitol gum usage.
In children with craniosynostosis, raised intracranial pressure (ICP) and upper airway obstruction (UAO) are both common features. However, potential interactions between UAO and ICP during sleep are poorly understood. The aim of the present study was to compare the levels of ICP during sleep between a group of patients with syndromic craniosynostosis (with facial involvement and consequent UAO) and a group of control patients with isolated unicoronal synostosis (with no facial involvement and normal upper airways). Polygraphic cardiorespiratory sleep studies with continuous monitoring of ICP were performed during unsedated sleep in 13 children with syndromic craniosynostosis and 7 control patients with isolated unicoronal synostosis only. In the syndromic group, UAO was present in 11 out of 13 patients, with 8 out of 13 having frank obstructive sleep apnoea. In contrast, none of the control patients showed signs of UAO during sleep. There was no evidence of central apnoeas in any of the patients studied. Clinical histories taken from parents tended to underestimate the severity of the respiratory problems. Elevated ICP was seen in 10 of the 13 syndromic patients, with borderline raised ICP in the remaining three cases. In contrast, raised ICP was seen in only 3 of the 7 control patients, with borderline raised levels in 2 of the 7. For both patient groups, ICP was higher during active sleep compared to quiet sleep. Multiple regression analysis showed that ICP during active sleep was dependent upon disease severity (unicoronal/ multiple synostosis) and to the baseline ICP level during quiet sleep. Both raised ICP and airway obstruction were more apparent during active sleep. There was a significant correlation between severity of UAO and increased ICP in active sleep. We conclude that obstructive respiratory problems are frequent in the syndromic patients, and can be severe in a large proportion of cases; intracranial hypertension is also frequent in this group. Further studies are required to investigate the possibility of a causal relationship between upper airway obstruction and raised intracranial pressure.