Long term continuous domiciliary oxygen therapy by transtracheal catheter.

Long term continuous oxygen therapy improves prognosis in patients with hypoxaemic chronic airflow limitation. Transtracheal delivery of oxygen permits adequate oxygenation of such patients at lower flow rates than are required for delivery by nasal cannulas, thus increasing the time for which portable oxygen cylinders can be used and improving the efficacy of domiciliary oxygen concentrators in patients with refractory hypoxaemia. In a study of the long term acceptability and risks of transtracheal oxygen in 37 patients, with a total follow up of 595 patient-months, most patients reported symptomatic benefit and four have used transtracheal oxygen successfully for more than four years. Problems have included surgical emphysema (4 patients), catheter fracture (9), local infection (34), and catheter dislodgement (21); but these have been relatively infrequent and in general have not caused important clinical problems. Transtracheal oxygen therapy was discontinued in 10 patients before death for various reasons, including infection (2 patients), catheter fracture (1), and surgical emphysema (1). Accumulation of mucus balls has not been a problem. It is concluded that transtracheal oxygen therapy is a safe and acceptable alternative to nasal cannulas in well motivated patients with hypoxaemia due to chronic airflow limitation who are keen to pursue an active life.     

Immunolymphoscintigraphy of pulmonary and mediastinal lymph nodes in dogs: a new approach to lung cancer imaging

Despite improved resolution with new imaging techniques, surgical confirmation of mediastinal lymph node status is often required for reliable staging of patients with non-small cell lung cancer. Recent scintigraphic studies suggest that s.c. administration of radiolabeled antibodies can be more efficient than the i.v. route for targeting regional lymph nodes in animals and humans. To determine if this approach could be applied to the lymphatics of the lung, we injected both specific and irrelevant radiolabeled monoclonal antibodies via a flexible fiberoptic bronchoscope through the mucosa of lobar bronchi in normal dogs. The injected antibodies were expected to drain by way of local lymphatic vessels toward the central lymph nodes, in effect following the same pathway as do cells metastasizing to these nodes during early regional tumor dissemination. To accomplish this, anesthetized dogs were intubated and then coinjected with the two labeled antibodies [600 microCi/100 micrograms (total)] through a fiberoptic bronchoscope. The animals were serially imaged and then autopsied 14-36 h after injection. Individual hilar and carinal nodes contained over 1% of the injected 131I-labeled specific antibody dose and the average selectivity was 2.5:1 with respect to a coinjected irrelevant IgG. Distant organs (mesenteric lymph node, liver, spleen, bone marrow, and lung parenchyma other than the injection site) contained much less radioactivity, and those sites accumulated a greater fraction of the non-specific labeled antibody. The ratio of iodine-131 to iodine-125 counts between hilar/carinal lymph nodes and abdominal lymph nodes ranged from 15:1 to 100:1. These initial studies indicate efficient delivery of antibody to a subset of the regional nodes via pulmonary lymphatics. They suggest the feasibility of this technique which may be of use in the detection and perhaps therapy of human lung cancer metastases in regional lymph nodes.     

Lithium and 5-HT1A receptor sensitivity: a neuroendocrine study in healthy volunteers

The effect of lithium administration (800 mg daily for 7 days) on the neuroendocrine and temperature responses to the 5-HT_1A receptor agonist, gepirone, was studied in eight healthy male volunteers. Gepirone (20 mg orally) significantly increased plasma levels of prolactin, growth hormone, corticotropin and cortisol, and lowered oral temperature. None of these responses was significantly altered by lithium treatment. The results suggest that the ability of short-term lithium treatment to increase 5-HT-mediated neuroendocrine responses in humans is unlikely to be related to changes in the sensitivity of pre- or post-synaptic 5-HT_1A receptors.     

Malignant melanoma over a fifty-year period: a histological evaluation

The incidence of primary cutaneous malignant melanoma is increasing in the developed countries. Cutaneous malignant melanomas diagnosed in our Department over a period of fifty years from 1930 to 1980 were examined to see if there was any change in their histological features. In 1930 and 1955, over 90% of malignant melanomas presented as tumours infiltrating deep into the subepithelial tissue. By 1980, 55% of tumours presented with deeply infiltrating lesions and only 20% occurred at a stage where adequate local excision could provide hope of a cure. There is thus a need for greater awareness among the medical profession and the public if we hope to be able to treat malignant melanomas at an early stage.     

Incomplete excision of the gallbladder during laparoscopic cholecystectomy

Dissection and transection of the cystic duct close to the gallbladder has been advocated as a means of avoiding common bile injury during laparoscopic cholecystectomy (LC). We present three cases in which inadequate identification of the gallbladder—cystic duct junction resulted in incomplete cholecystectomy. In two patients an unsecured gallbladder infundibulum presented as cystic duct leaks and one patient developed recurrent symptomatic cholelithiasis. These cases emphasize the need for complete dissection and visualization of the cystic duct at the gallbladder prior its division and secure ligation during LC.     

Attitudes toward psychiatry among Irish final year medical students

This study investigated the attitudes of medical students towards psychiatry, both as a subject on the medical curriculum and as a career choice. Three separate questionnaires previously validated on medical student populations were administered prior to and immediately following an 8-week clinical training programme. The results indicate that the perception of psychiatry was positive prior to clerkship and became even more so on completion of training. On completion of the clerkship, there was a rise in the proportion of students who indicated that they might choose a career in psychiatry. Attitudes toward psychiatry correlated positively with the psychiatry examination results. Those that intended to specialise in psychiatry achieved significantly higher examination scores in the psychiatry examination.     

Malignant pleural effusions: pleurodesis using a small-bore percutaneous catheter

This study describes our experience using a percutaneously placed small-bore catheter for drainage of malignant pleural effusions and subsequent instillation of a sclerosing agent to obliterate the pleural space. We treated 15 consecutive patients with known metastatic cancer and a symptomatic pleural effusion. Twelve patients survived for more than four weeks after the procedure; 11 of these 12 patients had a successful objective clinical response. The procedure was well tolerated, with little or no discomfort during catheter placement and the maintenance period. No serious complications were encountered. We conclude that the use of a small-bore percutaneously placed "pneumothorax" catheter in the management of malignant pleural effusions is an effective and more comfortable alternative to large-bore closed-tube thoracostomy.     

Differential expression of osteogenic factors associated with osteoinductivity of human osteosarcoma cell lines

Differential expression of multiple osteogenic factors may be responsible for the different osteoinductivity of osteosarcoma cell lines. We compared in vivo osteoinductivity of human osteosarcoma cell lines (Saos-2 vs. U-2 OS) in nude mice, and their in vitro expression of various osteogenic factors of protein level by quantitative immunocytochemistry and mRNA level by RT-PCR and/or in situ hybridization. Saos-2 cells, but not U-2 OS, were osteoinductive in vivo. Significantly higher expression (independent t-test, all p < 0.005) of osteogenic factors were observed in Saos-2 cells compared with U-2 OS, which included bone morphogenetic proteins (particularly BMPs-2, 3, 4, and 7), transforming growth factor-beta (TGF-beta), BMP receptor (BMPR)-1A, receptor-regulated Smads (R-Smads), Smads 1, 2, and 5, and common-mediator Smad (Co-Smad), Smad 4. In contrast, U-2 OS cells expressed higher levels of inhibitory Smad 6 (I-Smad) protein than Saos-2 cells (p < 0.001). These results suggest that a combination of osteogenic factors (BMPs, TGF-beta, BMPRs, and R/Co-Smads) against I-Smad may play important roles in the Saos-2 cell osteoinductivity. This may have a clinical implication in selecting key osteogenic factors for combined therapy for bone defect diseases. The characterized cell lines can be used as positive and negative controls for the assessments of both in vitro and in vivo bone formation capabilities of designed tissues or biomaterials.