Adhesive and degradative properties of human placental cytotrophoblast cells in vitro.

Human fetal development depends on the embryo rapidly gaining access to the maternal circulation. The trophoblast cells that form the fetal portion of the human placenta have solved this problem by transiently exhibiting certain tumor-like properties. Thus, during early pregnancy fetal cytotrophoblast cells invade the uterus and its arterial network. This process peaks during the twelfth week of pregnancy and declines rapidly thereafter, suggesting that the highly specialized, invasive behavior of the cytotrophoblast cells is closely regulated. Since little is known about the actual mechanisms involved, we developed an isolation procedure for cytotrophoblasts from placentas of different gestational ages to study their adhesive and invasive properties in vitro. Cytotrophoblasts isolated from first, second, and third trimester human placentas were plated on the basement membrane-like extracellular matrix produced by the PF HR9 teratocarcinoma cell line. Cells from all trimesters expressed the calcium-dependent cell adhesion molecule cell-CAM 120/80 (E-cadherin) which, in the placenta, is specific for cytotrophoblasts. However, only the first trimester cytotrophoblast cells degraded the matrices on which they were cultured, leaving large gaps in the basement membrane substrates and releasing low molecular mass 3H-labeled matrix components into the medium. No similar degradative activity was observed when second or third trimester cytotrophoblast cells, first trimester human placental fibroblasts, or the human choriocarcinoma cell lines BeWo and JAR were cultured on radiolabeled matrices. To begin to understand the biochemical basis of this degradative behavior, the substrate gel technique was used to analyze the cell-associated and secreted proteinase activities expressed by early, mid, and late gestation cytotrophoblasts. Several gelatin-degrading proteinases were uniquely expressed by early gestation, invasive cytotrophoblasts, and all these activities could be abolished by inhibitors of metalloproteinases. By early second trimester, the time when cytotrophoblast invasion rapidly diminishes in vivo, the proteinase pattern of the cytotrophoblasts was identical to that of term, noninvasive cells. These results are the first evidence suggesting that specialized, temporally regulated metalloproteinases are involved in trophoblast invasion of the uterus. Since the cytotrophoblasts from first trimester and later gestation placentas maintain for several days the temporally regulated degradative behavior displayed in vivo, the short-term cytotrophoblast outgrowth culture system described here should be useful in studying some of the early events in human placen

The transiency of oropharyngeal colonization with gram-negative bacilli in residents of a skilled nursing facility.

To determine the duration and persistence of gram-negative bacillary (GNB) oropharyngeal colonization over a specified period and the risk of subsequent GNB pneumonia developing in nursing home patients, we prospectively cultured for 31 weeks the oropharynges of patients in a skilled nursing facility. Over a 31-week period, an average of 13.8 percent of the patients showed colonization (weekly prevalence rates ranged from 0 to 29 percent). No patient had pneumonia during the study period. We concluded that the presence of GNB in the oropharynx of our patients is transient, continually changing over an extended period, and that GNB colonization as a transient occurrence is not directly associated with an increased risk of GNB pneumonia. Our data also emphasize the limitations of previously described single-culture survey studies in predicting the importance of GNB oropharyngeal colonization.

The use of the laryngeal mask airway to facilitate the insertion of a percutaneous tracheostomy.

We report the use of the laryngeal mask airway to facilitate the insertion of a percutaneous tracheostomy (Ciaglia kit) in two patients. This method has not been reported previously. We believe that in selected patients the technique described increases the ease of placement of a percutaneous tracheostomy.

Iatrogenic anaemia? A survey of venesection in patients in the intensive therapy unit.

In 30 consecutive patients admitted to the Intensive Therapy Unit, the volume of blood taken for investigations was recorded. Results were available for 26 patients. Total venesection volume averaged 336 ml. Venesection volume averaged 55.7 ml/day after the first 24 hours. The mean haemoglobin on admission was 11.5 g/d litre. Blood loss was related to both APACHE score and length of stay (APACHE.day), to the presence of arterial and central venous catheters, and to the need for mechanical ventilation. Iatrogenic blood loss of this magnitude will cause anaemia if it continues.

Characterization of renal prolactin-binding sites of two amphibians (Ambystoma tigrinum and Rana catesbeiana) and a reptile (Pseudemys scripta elegans).

The specific binding of 125I-ovine prolactin (oPRL) to renal membrane preparations from Pseudemys scripta elegans, Ambystoma tigrinum, and Rana catesbeiana was characterized. All three membranes showed specific oPRL binding that was dependent upon time, temperature, pH, and membrane concentration. Scatchard analysis of the binding of 125I-oPRL revealed high-affinity sites with KA values of 2.1 X 10(10), 3.6 X 10(10), and 1.25 X 10(10) M-1 for kidney membranes of Pseudemys, Ambystoma, and Rana, respectively. In addition, there was a low-affinity site on the Ambystoma membranes. The binding capacities ranged from 31 to 70 fmol/mg of membrane protein. The hormonal specificity of these membranes was studied by competing increasing amounts of oPRL, human growth hormone (hGH) derived from recombinant DNA techniques, bovine (b) GH, and human placental lactogen (hPL) with 125I-oPRL. The oPRL standard and hGH were the most potent competitors in all three assays, although hGH was not as potent as the oPRL. Human PL was moderately active in the turtle kidney assay, weakly active in the Ambystoma radioreceptor assay, and inactive in the bullfrog assay. Bovine GH had low potency on the turtle membranes and was inactive in the amphibian assays. The results of these studies indicate that the characteristics of renal PRL receptors of Pseudemys, Ambystoma, and Rana are similar to those of lactogenic receptors throughout the vertebrates. In addition, these data provide evidence for the first time of renal PRL receptors in a reptile.

Volatile agent use: perception and practice. A survey of agent use over a 3-year period.

We calculated the quantity, as MAC hours and MAC hours anaesthetic, of halothane, enflurane and isoflurane, used in this Health District over a 3-year period. Halothane accounted for 77% of anaesthesia in the first year and for 57% in the final year. Overall usage of volatile agents decreased. Fifteen consultants and 19 senior registrars perceived, in a survey of practice, only a change in relative use of volatile anaesthetic agents with a large swing from halothane to both enflurane and isoflurane. Half the anaesthetists stated that the medicolegal consideration was the prime reason for their change. The perceived total demise of halothane does not appear to have been realised, despite individual anaesthetist's perceptions.

Characterization of hepatic growth hormone binding sites in two fish species, Gillichthys mirabilis (Teleostei) and Acipenser transmontanus (Chondrostei).

To obtain information on the presence of growth hormone (GH) receptors in liver of nonmammalian vertebrates the specific binding of 125I-bovine growth hormone (bGH) to liver membranes of seven species representing the major groups was studied by radioreceptor assay. A substantial degree of specific binding was detected with sturgeon (Acipenser transmontanus) liver membranes and a much lower amount was detected on hepatic membranes of Gillichthys mirabilis. No significant specific binding was detected on liver membranes of pigeon, turtle, bullfrog, tilapia, or leopard shark. Gillichthys and sturgeon liver membranes were further characterized and compared with hepatic membranes from male rabbits. The sturgeon and Gillichthys membranes showed binding that was dependent upon time, temperature, pH, and membrane concentration. Scatchard analysis of the binding of 125I-bGH to sturgeon and rabbit membranes revealed both high and low affinity binding sites. The high affinity sites had KA values of 3.1 X 10(11) and 1.0 X 10(11) M-1, and capacities of 12 and 50 fmol/mg protein, respectively. Membranes from Gillichthys liver contained only a single class of binding sites with a KA of 6.7 X 10(9) M-1 and a binding capacity of 49 fmol/mg. Hormonal specificity of the sturgeon and Gillichthys hepatic binding sites was studied using methionyl-human GH (met-hGH), ovine prolactin (oPRL), and a crude preparation of sturgeon (st)GH. The met-hGH and stGH inhibited the binding of 125I-bGH to sturgeon liver membranes while only met-hGH displaced labeled bGH from Gillichthys liver membranes. One microgram of oPRL did not significantly inhibit 125I-bGH binding in either membrane assay. Based on these studies, sturgeon hepatic GH receptors seem to be more like those of nonprimate mammals than those of teleosts. Our results, in conjunction with the data of J. N. Fryer (Gen. Comp. Endocrinol. 39, 123-130 (1979)), indicate that considerable evolutionary divergence has occurred among teleost hepatic GH receptors. Thus, vertebrate GH receptors seem to have undergone at least as much evolution as has the hormone itself.

Reducing smoking. The effect of suggestion during general anaesthesia on postoperative smoking habits.

In a double-blind randomised trial, 122 female smokers undergoing elective surgery were allocated to receive one of two prerecorded messages while fully anaesthetised. The active message was designed to encourage them to give up smoking whilst the control message was the same voice counting numbers. No patient could recall hearing the tape. Patients were asked about their postoperative smoking behaviour one month later. Significantly more of those who had received the active tape had stopped or reduced their smoking (p < 0.01). This would suggest a level of preconscious processing of information.

Validation of a croup score and its use in triaging children with croup.

The Syracuse croup scoring system was validated in 165 children with croup who were admitted to an intensive therapy unit for assessment over a one year period. The unit served as a croup triage point for Cardiff and its environs. A score of > 5 was taken as an indication that a patient was at risk of upper airway obstruction and was used to support a triage decision by the junior hospital doctor to admit a patient to the intensive therapy unit. All patients with an initial score < or = 5 were considered safe for transfer to a general paediatric ward and none of these required subsequent admission to intensive care. This score was then tested on a further 134 children with croup, in order to identify those patients who required specialised monitoring, observation or treatment in intensive care. A score of > 5 gave a specificity of 100% and a sensitivity of 80%. Croup scoring continued after admission on the general paediatric wards. Two patients who were originally admitted to the intensive therapy unit with a score > 5 improved within 6 h and were transferred to the general ward with a score < or = 5. These children subsequently required readmission to the intensive therapy unit. Our tracheal intubation rate of 2% was low and may relate to the routine use of regular adrenaline nebulisation. We recommend this scoring system to other paediatric departments for initial triaging decisions and for documenting progress on the wards.

p53 mutations do not predict response to paclitaxel/radiation for nonsmall cell lung carcinoma.

BACKGROUND: Mutations in the tumor suppressor gene p53 have been associated with resistance to ionizing radiation and chemotherapy. Paclitaxel and concurrent radiation (paclitaxel/RT) achieve high response rates with locally advanced nonsmall cell lung carcinoma (NSCLC). In vitro data and animal studies suggest that paclitaxel may have a unique ability to activate tumor cell apoptosis in the absence of wild-type p53 function. The authors sought to determine whether p53 mutations affect response to paclitaxel/RT in patients with locally advanced NSCLC. METHODS: Thirty patients with Stage IIIA or IIIB NSCLC who participated in Brown University Oncology Group protocols utilizing paclitaxel/RT had tumor tissue that was adequate for analysis. Mutations were detected in tumor tissue by single-strand conformation polymorphism analysis of exons 5 through 8 of the p53 gene, and confirmed by direct sequencing. RESULTS: Mutations in p53 were found in 12 of 30 patients (40%). The response rates (complete plus partial) of 75% for patients with tumors with p53 mutations, and 83% for patients with wild-type p53, did not differ significantly (P = 0.70). CONCLUSIONS: p53 mutations do not predict response of patients with NSCLC to paclitaxel/RT. This finding is in striking contrast to results with other chemotherapeutic agents and ionizing radiation. These clinical data support in vitro data and animal studies regarding the unique mechanism of the action of paclitaxel. Further investigation is needed to determine the mechanism of lung tumor cell death after paclitaxel/RT. These results suggest that paclitaxel/RT may be an active regimen for patients with other locally advanced neoplasms with high rates of p53 gene mutations.