Segments of chromosomal DNA from Rhynchosciara americana that undergo additional rounds of DNA replication in the salivary gland DNA puffs have only weak ARS activity in yeast.

We have constructed a library of recombinant phage containing DNA from salivary gland chromosomes of Rhynchosciara americana. We have isolated phage from this library that carry sequences homologous to cDNA clones that hybridize in situ to the DNA puffs at the polytene chromosome regions C3 and C8. This has enabled us to demonstrate a 16-fold amplification of the genomic DNA sequences at these regions during DNA-puffing. At the C8 site there is a sequence element that has characteristics of 'scrambled' moderately repetitive DNA. This is located within 3 kb from the gene encoding a 1.95-kb mRNA. We have assayed restriction fragments from the two DNA puffs for Ars activity in yeast. The only strong Ars activity is associated with a part of the moderately repetitive DNA element from the C8 puff which is not present at this site in all animals.

Parapneumonic empyema. A pitfall in diagnosis.

Two patients eventually shown to have empyema were encountered in which the initial thoracentesis revealed fluid compatible with either a simple or a complicated parapneumonic effusion. In both cases, the diagnosis of empyema was made by a second thoracentesis done at a close interval of time from a different site. Therefore, the physician should approach parapneumonic effusions systematically, and remember that in some cases, multiple thoracenteses may be required to make the correct diagnosis of an empyema.

Doxycycline pleurodesis for pneumothorax in patients with AIDS.

Since first described in 1984, nontraumatic pneumothoraces in patients with AIDS has become more common. When compared with spontaneous pneumothorax in the general population, pneumothoraces in patients with AIDS are often complicated by prolonged air leaks as well as higher recurrence rates. Chemical pleurodesis has an important role in the management of these complications. The most experience with chemical pleurodesis uses tetracycline hydrochloride as the sclerosing agent; however, this agent is no longer available. Doxycycline has been used in pleurodesis of malignant effusions, but its use in managing pneumothoraces is limited. We present five patients who have AIDS with a total of seven pneumothoraces. Each patient experienced a persistent air leak. Six of the pneumothoraces were managed successfully with doxycycline. Although the follow-up period was limited, there were no recurrences noted and the only side effect seen was chest pain in four which was easily controlled with narcotics. Doxycycline sclerotherapy can be used effectively for pleurodesis in the management of nontraumatic pneumothorax in the patient with AIDS.

Dyspnea and pulmonary function in the L-tryptophan-associated eosinophilia-myalgia syndrome.

We reviewed the pulmonary history, dyspnea ratings, and pulmonary function test results in 16 patients with L-tryptophan-induced eosinophilia myalgia syndrome to determine the correlation between reported pulmonary complaints and pulmonary function abnormalities. All patients reported pulmonary symptoms. Dyspnea, seen in 14 of 16 (87 percent) patients, was the most common symptom. The severity of dyspnea was graded by the baseline dyspnea index and the oxygen cost diagram. Pulmonary function testing including maximal static inspiratory and expiratory pressures were measured. The DCO was diminished in 12 of 16 (75 percent) patients. The MSIP was decreased in seven out of ten (70 percent) and the MSEP was decreased in nine out of ten (90 percent) of those patients tested. There was a statistically significant correlation between the severity of dyspnea as graded by the BDI and OCD, and the decrease in DCO. These results and a review of the literature of the pulmonary manifestations of EMS lead us to conclude that patients with EMS have a high prevalence of dyspnea, and it appears to be caused by both lung parenchymal involvement, as well as respiratory muscle weakness.

Differential lobe lavage for diagnosis of acute Pneumocystis carinii pneumonia in patients receiving prophylactic aerosolized pentamidine therapy.

The diagnostic yield of bronchoalveolar lavage (BAL) for Pneumocystis carinii pneumonia (PCP) in patients infected with human immunodeficiency virus has been reported to be 95 percent, but falls to 62 percent in patients receiving aerosolized pentamidine. Because aerosolized pentamidine appears to be preferentially deposited in the middle and lower lobes, we postulated that an upper lobe lavage would have a higher diagnostic yield than the standard middle/lower lobe lavage in patients receiving aerosolized pentamidine. Twenty-five patients receiving aerosolized pentamidine suspected of having acute PCP underwent separate BAL of an upper lobe and lower lobe as well as transbronchial biopsy. Fifteen of the 25 (60 percent) were diagnosed as having PCP. Of the 15, one had the samples inadvertently combined. In the remaining 14, BAL was positive for P carinii organisms in 12 lavages of the lower lobe and 14 of the upper lobe. Upper lobe lavage had statistically significantly more P carinii organisms by semiquantitative technique than the lower lobe. In patients receiving aerosolized pentamidine, who develop acute PCP, an upper lobe lavage may have a higher diagnostic yield than the standard middle/lower lobe lavage. In addition, the transbronchial biopsy specimen offered no treatable diagnosis that was not made by lavage alone in the 25 patients. This raises the question of the utility of transbronchial biopsies in these patients.

Recurrent bronchogenic cyst. An argument for complete surgical excision.

A case of a recurrent bronchogenic cyst in a 42-year-old woman 25 years after original resection led to a review of the therapeutic modalities for the management of bronchogenic cysts. Recurrence of bronchogenic cysts is a reason for complete surgical excision of symptomatic bronchogenic cysts at initial presentation. If either asymptomatic or symptomatic bronchogenic cysts are drained or partially excised, long-term follow-up is indicated to detect recurrence.

New air-fluid levels in bullous lung disease: a reevaluation.

Air-fluid levels appearing in lung bullae are always considered to indicate infection and therefore conservative management with prolonged antibiotics and observation to resolution is the recommended approach. This article presents a case of bullous lung disease with new air-fluid levels, in which a diagnosis of malignancy was made by aspiration of the fluid. This association is discussed and a more aggressive evaluation of such patients to include computed tomography of the chest and fluid sampling is recommended before a presumption of benignity is made.

Clonal divergence in lung cancer development is associated with allelic loss on chromosome 4.

Patients who receive curative treatment for lung cancer can develop additional lung tumors that may or may not be related to the original tumor and thus require different clinical management. If a subsequent tumor has a pattern of allele loss, revealed by allelotype analysis, overlapping that of the first tumor, it is believed to be a local recurrence or metastasis. In this case history, we present loss of heterozygosity analyses of the original primary tumor, and two second primary tumors occurring in the ipsilateral and the contra-lateral lungs. The allelotyping suggests that these tumors are all clonally related but concordance is not complete. Our interpretation is that the original primary tumor and the two new primary tumors have developed to full malignancy independently, but are clonally related, possibly via a clone of motile progenitor cells. Deletion mapping of DNA from biopsies of this patient delineated a region in 4p16 that we had previously shown to be lost in the transition from carcinoma in situ to invasive tumor. We identified a minimally deleted region encompassing six genes including two candidate tumor suppressor genes, CRMP1 a lung cancer metastasis-suppressing gene and PPP2R2C a gene for a regulatory subunit of the PP2 complex known to suppress tumorigenesis, particularly viral induced transformation.

Maximizing oxygen delivery when resuscitating patients from shock. Clinical guidelines as well as some practical pointers.

In patients with shock and evidence of hypoperfusion, target therapy at increasing oxygen delivery and decreasing oxygen consumption. To augment delivery, increase arterial oxygenation (with mechanical ventilation and high levels of inspired oxygen), hemoglobin level to at least 10 g/dL (with transfusions of red blood cells), and cardiac output (with hydration and inotropic support). Avoid vasopressors because they increase afterload and thereby decrease cardiac output and oxygen delivery. To reduce oxygen consumption, consider antipyretics (to lower metabolic demand) and mechanical ventilation plus sedatives or paralytics (to decrease the work of breathing). Continue therapy until oxygen consumption is no longer coupled to delivery.

32P, 33P and 35S: selecting a label for nucleic acid analysis.

The advent of 33P nucleotide triphosphates has widened the options available for labelling nucleic acids. Choosing the most appropriate label requires a careful consideration of experimental needs and circumstances.

Injuries sustained by aircrew on ejecting from their aircraft.

This paper describes some of the injuries sustained by the aircrew who ejected from their aircraft after a mid-air collision, and discusses the types of injury that such patients may suffer.

Outbreaks of influenza A in nursing homes in Sheffield during the 1997-1998 season: implications for diagnosis and control.

Three recent outbreaks of influenza A in nursing and residential homes in Sheffield were characterized by high attack rates among both residents and staff, and a high mortality rate among residents. The epidemiology of the outbreaks was unusual in that all three occurred towards the end of a quiet influenza season, against a generally low level of community activity, and involved strains of influenza that were not included in the current season's vaccine. The outbreak investigation was aided by the use of a novel rapid diagnostic technique. In future the combination of vaccination, surveillance, rapid diagnosis and new antineuraminidase drugs should improve prospects for control of influenza within closed communities.

Widely differing degrees of sequence conservation of the two types of rDNA insertion within the melanogaster species sub-group of Drosophila.

We have examined the distribution of sequences homologous to the type I and type II rDNA insertions of Drosophila melanogaster in its sibling species. Each of the six species we have examined has sequences homologous to the type I insertion, which have undergone extensive divergence by the criterion of their EcoRI, BstI and HindIII restriction patterns. We have isolated cosmid clones containing type I sequences from D. simulans and D. mauritiana, the two species most closely related to D. melanogaster. Southern hybridisation analysis of these clones indicates that, as in D. melanogaster, the type I sequences can exist independently of rDNA and can also dissociate to give sub-components homologous to the right hand segment of the D. melanogaster type I insertion. The type II sequences, on the other hand are present in five out of the six species, but their restriction endonuclease cleavage profile is highly conserved. The differences in the degree of conservation of the two types of insertion sequence are discussed.

The use of charge-coupled devices in the quantitative evaluation of images, on photographic film or membranes, obtained following electrophoretic separation of DNA fragments.

Charge-coupled devices can provide an excellent means for the quantification of DNA band images on membranes and photographic film. However, proper consideration must be given to important parameters such as signal-to-noise ratio and resolution, especially in applications which demand the use of large format media. When employed in the direct imaging of chemiluminescent blots, the charge-coupled device can provide equal or better sensitivity than that obtained by indirect methods using film, with the additional advantages of wide dynamic range and freedom from the vagaries of film processing.

Site specific insertion of a type I rDNA element into a unique sequence in the Drosophila melanogaster genome.

We describe a cloned segment of unique DNA from the Oregon R strain of Drosophila melanogaster that contains a short type I insertion of the kind principally found within rDNA. The predominant type I rDNA insertion is 5kb in length, but there are also a co-terminal sub-set of shorter type I elements that share a common right hand junction with the rDNA. The insertion that we now describe is another member of this sub-set. The right hand junction of the type I sequence with the unique DNA is identical to the right hand junction of the type I sequences with rDNA. There is no significant feature within the insertion sequence that could have determined the position of the left junction with the sequence into which it is inserted. Like the corresponding short type I insertions in rDNA, the insertion into the unique DNA is flanked on both sides by a duplicated sequence, which in this case is 10 base pairs long. The cloning of a sequence corresponding to the uninterrupted unique location was facilitated by the observation that the Karsnas strain of D. melanogaster contains only uninterrupted sequences of this kind. The duplicated sequence at the target site for the insertion is only present as a single copy in the uninterrupted DNA. The sequence of the target site for the insertion (ACTGTTCT) in the unique segment shows a striking homology to the target in rDNA (ACTGTCCC).

Magnetic bead purification of M13 DNA sequencing templates.

A method for the preparation of multiple M13 DNA sequencing templates is described. No phenol extraction is required and the procedure can be carried out in Eppendorf tubes or 96-well microtiter plates. Starting with a phage supernatant, the entire procedure is carried out in the same reaction vessel and all separation steps are based on a novel application of magnetic bead separation. The design of a 96-well magnetic separator is presented and the application of the method for large-scale sequencing is discussed.