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Biomedical subjects

J Richardson

Publications and source records attributed to J Richardson.

At least 199 records · Page 11Linked to original sources
PubMed1994

Surgical management of intrathoracic oesophageal rupture.

Intrathoracic oesophageal rupture is a life-threatening condition that requires early diagnosis and effective treatment if death or serious prolonged illness is to be avoided. Six consecutive patients with intrathoracic oesophageal rupture were treated by debridement and irrigation of the mediastinum and primary suture closure with reinforcement of the suture line by pedicled omentum. The cause of the rupture was Boerhaave's syndrome in five patients and compressed air injury to the oesophagus in one. All but one patient presented more than 24 h after onset of symptoms, with a mean of 38 (range 12-72) h. All the patients recovered well with no postoperative oesophageal leakage. The mean hospital stay was 11.5 (range 9-15) days. Irrespective of the duration of the oesophageal rupture, aggressive resuscitation and prompt primary suture closure with reinforcement of the suture line with a well vascularized pedicled tissue flap is required for optimal results.

Adult↗
PubMed1994

The envelopes of two ecotropic murine leukemia viruses display distinct efficiencies in retroviral vaccination by interference.

In cell cultures infected with a retrovirus, the expression of the viral envelope interferes with superinfection by retroviruses which recognize the same receptor. We have previously demonstrated that vaccination of susceptible strains of mice (of the Mus musculus species) with the attenuated ecotropic Friend murine leukemia virus (F-MuLV) B3 efficiently protects against the early hemolytic anemia and the erythroleukemia induced by a challenge with the virulent F-MuLV 57 through a similar in vivo mechanism of interference to superinfection (A. Corbin and M. Sitbon, J. Virol. 67, 5146-5152, 1993). Vaccination with the heterologous ecotropic Moloney-MuLV (M-MuLV) efficiently protects against the early hemolytic anemia but has a weak protective effect on the F-MuLV 57-induced erythroleukemia. Furthermore, vaccination with the attenuated F-MuLV B3 had only a transient protective effect on M-MuLV-induced thymomas. These different efficiencies of F- and M-MuLV to confer protection in this model of vaccination by interference were mostly due to envelope sequences, indicative of distinct in vivo interference properties of the two ecotropic envelopes.

Animals↗
PubMed1994

Cost utility analysis: what should be measured?

The paper re-examines the issue of the appropriate unit for measuring output in cost utility analysis and the technique that will measure it. There are two main themes. The first is that utility, as it is often conceived and quantified, is not an appropriate basis for measurement. Consequently, a question arises concerning the selection of an appropriate unit of measurement. The second theme is that there is a need to establish criteria for the evaluation of measurement units. Four criteria are proposed which follow from commonly accepted social objectives and from the requirements of a measurement unit. It is concluded that, as judged by these criteria, the measurement units produced by the time trade-off and person trade-off (equivalence) techniques are more satisfactory than the units produced by the rating scale, magnitude estimation or the standard gamble.

Choice Behavior↗
PubMed1994

Results of surgical treatment of stage III lung cancer.

The role of surgery in the management of Stage III lung cancer is controversial. A retrospective analysis of our experience with 220 Stage III patients treated surgically (Stage IIIa n = 174, Stage IIIb n = 46) form the basis of this report. Of the 140 patients who underwent resection only 88 were considered to be potentially curative, all but two being operated in Stage IIIa. The overall 5-year survival rate for Stage III lung cancer was 12.1% whilst curative resection had a 5-year survival rate of 31.8%. The 5-year survival rate increased to 42% with curative resection for T3N0M0 patients. There were no 5-year survivors with incomplete resection. There were no 5-year survivors in Stage IIIb disease. Five-year survival rates for N0 (n = 62), N1 (n = 78), and N2 (n = 80) irrespective of T status were 37.2%, 3.4% and 5.6%, respectively. The operative mortality rate was only 3.4% for curative resection while palliative or non-resection patients had a mortality rate of 10.6%. Eighty-eight patients, 55 of Stage IIIa and 23 of Stage IIIb had postoperative radiotherapy with a median survival of 12 and 9 months, respectively. Fifteen small cell carcinoma patients had postoperative adjuvant chemotherapy with a median survival of 6.5 months. The only 5-year survivor in this group also had a curative resection. We conclude that metastasis to lymph nodes usually implies systemic disease and a poor prognosis. Surgical therapy continues to be the treatment of choice in a small subset of patients with Stage III resectable lung cancer discovered at thoracotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

Acute bilateral optic disc neovascularization.

PURPOSE: A case of bilateral acute neovascularization of the optic disc and peripapillary epiretina of unknown etiology in a previously healthy 26-year-old woman is discussed. METHODS: The clinical course of the disease, investigation, and treatment are presented in detail. RESULTS: Histopathologic examination of epiretinal tissue removed from the second eye at vitrectomy provided evidence of inflammatory disease and suggested a possible etiology. CONCLUSION: The cause of this patient's disease remains uncertain. Known causes of this disease were excluded as far as possible. Histopathologic examination of the epiretinal membrane from the second eye demonstrated an unusually increased inflammatory response and multiple intracytoplasmic inclusion bodies in neutrophils resembling mollicute-like organisms.

Acute Disease↗
PubMed1994

Relationship between ultraviolet radiation-induced immunosuppression and carcinogenesis.

The capacity of ultraviolet B (UVB) radiation to damage the cutaneous immune system has been extensively documented, and there is good reason to believe that UVB-induced damage is a critical, albeit permissive, factor in the development of sunlight-induced skin cancers. A summary of the evidence shows that acute, low-dose UVB protocols, which resemble quantitatively and qualitatively the manner in which human beings typically experience sun exposure, alter the cutaneous immune system in at least two important ways: they impair the induction of contact hypersensitivity to cutaneous antigens, and induce antigen-specific tolerance. In mice there is compelling evidence that immunogenetic factors dictate whether UVB radiation will impair contact hypersensitivity induction or not. The genetic loci that contain the relevant polymorphic alleles include tumor necrosis factor-alpha and lipopolysaccharide. Because the effects of UVB radiation on contact hypersensitivity induction are mimicked by intracutaneous injections of subinflammatory doses of tumor necrosis factor-alpha or cis-urocanic acid, the favored hypothesis to explain the mechanism of action of UVB radiation in UVB-susceptible individuals is that UVB-dependent transformation of trans- to cis-urocanic acid in the epidermis triggers the intracutaneous release of excess amounts of tumor necrosis factor-alpha. By transiently immobilizing Langerhans cells and other local antigen-presenting cells within the skin, the requirement that hapten be brought to the draining lymph node to sensitive naive hapten-specific T cells is not met, and contact hypersensitivity fails to develop. Because the UVB-susceptibility and UVB-resistance traits have also been demonstrated in human beings, the hypothesis is advanced that these traits are similarly under control of immunogenetic factors, and that a constellation of immune susceptibility genes contributes to the risk of developing sunlight-induced skin cancer. The cellular and molecular basis of UVB-induced tolerance is not as well described, but current evidence suggests that different mechanisms, and presumably different polymorphic genes, dictate whether tolerance will emerge after UVB exposure in mice. Because acute, low-dose UVB also induces tolerance in human beings, the immunogenetic factors that dictate tolerance of this type may also contribute to the risk of developing sunlight-induced skin cancer.

Animals↗
PubMed1994

Different abilities of Friend murine leukemia virus (MuLV) and Moloney MuLV to induce promonocytic leukemia are due to determinants in both psi-gag-PR and env regions.

Moloney murine leukemia virus (M-MuLV) is capable of inducing promonocytic leukemia in 50% of adult BALB/c mice that have received peritoneal injections of pristane, but Friend MuLV strain 57 (F-MuLV) is nonleukemogenic under similar conditions. It was shown earlier that these differences could not be mapped to the U3 region of the virus long terminal repeat, indicating the probable influence of structural genes and/or R-U5 sequences. In this study, reciprocal chimeras containing exchanged structural genes and R-U5 sequences from these two closely related viruses were analyzed for differences in ability to induce disease. Results showed that two regions of F-MuLV, psi-gag-PR and env, when substituted for those of M-MuLV were dramatically disease attenuating. The 5'-most region, which is widely distributed, overlaps with the 5' end of the env intron and includes the RNA packaging region, psi, the entire gag coding region, and the viral protease coding region (PR) of pol. It was also found that reciprocal constructs having substitutions of both of these regions of M-MuLV in an F-MuLV background allowed full reestablishment of promonocytic leukemia. These leukemias were positive for c-myb rearrangements which are characteristic of M-MuLV-induced promonocytic leukemias. Neither region alone, however, was sufficient to produce disease with a greater incidence than 13%. Further studies demonstrated that the inability of viruses with psi, gag, PR, or env sequences from F-MuLV to induce leukemia in this model system was not due to their inability to replicate in hematopoietic tissue, to integrate into the c-myb locus early on after infection in vivo, or to express gag-myb mRNA characteristic of M-MuLV-induced preleukemic cells and acute leukemia.

3T3 Cells↗
PubMed1994

Self-expanding tracheobronchial stents in the management of major airway problems.

The management of patients with critical major airway obstruction has been made possible by the recent introduction of expandable metal stents as the sole treatment or as an adjunct to other treatment modalities. To alleviate the distressing symptoms from tracheobronchial obstructions Gianturco self-expanding stents were used successfully in the management of 16 patients. The indications were; stenosis from postoperative strictures and recurrent tumours (n = 6), extrinsic compression from metastatic disease (n = 4), inoperable primary tumours of central airways (n = 4), airway collapse from relapsing polychondritis (n = 1), and endobronchial non-Hodgkin's lymphoma (n = 1). Fourteen patients have immediate relief of stridor and the remaining two patients were successfully weaned from ventilatory support. The stents were inserted under general anaesthesia through a rigid bronchoscope under direct vision. The ease of insertion under radiological control, self-expanding nature of the stents and the lack of major complications on follow-up of up to 22 months are particular advantages. The self-expanding tracheobronchial stents are a useful addition to our armamentarium in maintenance of the airways in patients with major airway stenosis and collapse.

Adult↗
PubMed1994

Differential influence of parental smoking and friends' smoking on adolescent initiation and escalation of smoking.

Smoking-related behaviors and attitudes of significant others (especially friends and parents) are among the most consistent predictors of adolescent smoking. However, theorists remain divided on whether the behaviors of significant others influence adolescent smoking directly or indirectly, and the relative influence of parental and peer smoking on adolescents' own smoking is still a matter of debate. In addition, little research has examined the role of significant others' behavior on different stages of smoking onset. In particular, not much information is available regarding gender and ethnic differences in social influences on smoking behavior. We use structural equation modeling to address these issues. Different theoretical perspectives from cognitive-affective theories (Ajzen 1985; Ajzen and Fishbein 1980) and social learning theories (Akers et al. 1979; Bandura 1969, 1982, 1986) have been integrated into a structural model of smoking influence. The results show that friends' smoking affects adolescent initiation into smoking both directly and indirectly, whereas parental smoking influences smoking initiation only indirectly. The data also show that friends' and parents' smoking affect smoking escalation only indirectly. In general, friends' smoking has a stronger effect on adolescents' smoking behavior, particularly on initiation. Multiple group comparisons of the structural models predicting smoking initiation among males and females reveal that parental approval of smoking plays a significant mediating role for females, but not for males. Comparisons of Whites, Blacks, Hispanics, and other ethnic groups reveal that there are some significant differences in the pathways of friends' influences among the four groups.

Adolescent↗
PubMed1994

Management of postpneumonectomy bronchopleural fistulae. A review.

The management of postpneumonectomy bronchopleural fistulae continues to constitute a major therapeutic challenge. Refinements of surgical techniques have reduced the incidence of this dreaded complication although it cannot be totally prevented. Management remains controversial. We report our recent experience of three patients with bronchopleural fistulae following a right pneumonectomy, two for bronchogenic carcinoma and another for non-tuberculous, suppurative lung disease. Our treatment of choice for these patients is, immediate pleural drainage together with parenteral broad spectrum antibiotics followed by endoscopic closure of the fistula with monomeric n-butyl-2-cyanoacrylate glue (Histoacryl blue, B Braun, Melsungen, Germany). The pleural space is then irrigated with Povidone Iodine to sterility following which the closed bronchial stump is reinforced following which the closed bronchial stump is reinforced and the pleural space obliterated by decortication, omentopexy and by a tailored thoracoplasty. This cosmetically acceptable treatment produces minimal functional disability and is achieved with minimal morbidity and mortality in these critically ill patients.

Aged↗
PubMed1994

Efficacy of pre-emptive analgesia and continuous extrapleural intercostal nerve block on post-thoracotomy pain and pulmonary mechanics.

OBJECTIVE: Thoracotomy results in severe pain and deleterious changes in pulmonary physiology. The literature suggests that these alterations in pulmonary mechanics are inevitable and can only be minimised but not prevented by effective analgesia. We have re-evaluated this concept and assessed the efficacy of pre-emptive analgesia [preincisional afferent block, premedication with opiate and/or non-steroidal anti-inflammatory drug (NSAID)] in conjunction with postoperative extrapleural continuous intercostal nerve block on postoperative pain and pulmonary function. MATERIALS AND METHODS: A prospective randomized study was conducted on 56 patients undergoing elective thoracotomy. Subjective pain relief was assessed on a linear visual analogue scale. Pulmonary function was measured on the day before operation and 12 hourly for 48 hours after operation. There were seven patients in each of the eight groups. RESULTS: The balanced analgesia group comprising preincisional block and premedication with opiate and NSAID (Group 1) had significantly better analgesia, needed less postoperative supplementary analgesics and maintained their preoperative pulmonary function postoperatively irrespective of the nature of the operation. The ranking of importance of the three components of the pre-emptive analgesia as assessed in this study are preincisional block, opiate premedication and premedication with NSAID's. No significant change in plasma levels of cortisol or glucose occurred in Group 1 patients from prior to induction of anaesthesia to 24 hours postoperatively, suggesting effective somatic and sympathetic afferent blockade had been achieved in these patients. There were no complications related to the infusion or the use of NSAID's. CONCLUSIONS: We conclude that a balanced analgesic regime comprising preoperative pain prophylaxis and postoperative maintenance analgesia by NSAID and continuous extrapleural intercostal nerve block will minimise and even reverse the expected decline in lung function after thoracotomy. The postoperative decline in lung function is not obligatory but primarily due to incisional pain and thus is preventable by effective analgesia. An ideal balanced pre-emptive analgesic regime should include preincisional local anaesthetic afferent block and premedication with opiates and a NSAID:

Administration, Rectal↗