Mediastinal space-occupying lesion with reduced perfusion of the left lung. Thoracic aortic aneurysm with compression of the left pulmonary artery

CONTEXT: An increase in the recreational use of personal watercraft (PWC) raises concern about an increase in associated injuries on a national level. OBJECTIVE: To estimate the relative frequency, types of injury, and demographic features of persons injured while using PWC in the United States. DESIGN: Case series. SETTING: Emergency department (ED) visits to hospitals participating a national probability sample. PARTICIPANTS: All persons treated for PWC-related injury from January 1,1990, through December 31, 1995. RESULTS: An estimated 32954 persons (95% confidence interval [CI], 22919-42989) with PWC-related injuries were treated in US hospital EDs, of which 3.5% were hospitalized. Personal watercraft-related injuries have increased significantly from an estimated 2860 in 1990 to more than 12000 in 1995. During this period, the number of PWC in operation increased 3-fold from approximately 241500 in 1990 to an estimated 760000 in 1995. The most prevalent diagnoses were lacerations, contusions, and fractures. MAIN OUTCOME MEASURES: The estimated number and percentage of patients treated in EDs for PWC-related injuries, by year, age, sex, and the number and rate per 1000 of PWC in operation by year. CONCLUSIONS: Since 1990, there has been at least a 4-fold increase in injuries associated with an increase in the recreational use of PWC. The rate of ED-treated injuries related to PWC was about 8.5 times higher (95% CI, 8.2-8.8; 1992 data) than the rate of those from motorboats. Specific training and adult supervision is recommended for minors using PWC. Furthermore, medical practitioners should encourage personal flotation device use and other protection for their patients who are known water enthusiasts.     

Role of nitric oxide in rat nephrotoxic nephritis: comparison between inducible and constitutive nitric oxide synthase

Nitric oxide (NO), generated by inducible NO synthase (iNOS) in migrating macrophages, is increased in glomerulonephritis. This study investigates the effect of NO inhibition on rat nephrotoxic nephritis (NTN) to clarify the role of NO production in glomerular damage. NTN was induced in Sprague Dawley rats by an injection of an anti-glomerular basement membrane (GBM) antibody. Urinary nitrite excretion and nitrite release from kidney slices (5.47 +/- 1.19 versus 2.15 +/- 0.73 nmol/mg protein, NTN versus Control, P < 0.05) were increased in NTN on day 2. Glomerular macrophage infiltration and intercellular adhesion molecule (ICAM)-1 expression increased from day 2. iNOS expression was increased in interstitial macrophages. Glomerular endothelial cell NOS (ecNOS) expression evaluated by counting immunogold particles along GBM was suppressed (0.06 +/- 0.02 versus 0.35 +/- 0.04 gold/micron GBM, P < 0.0001). Glomerular damage developed progressively. NG-nitro-L-arginine methyl ester (L-NAME), which inhibits both iNOS and ecNOS and aminoguanidine (AG), a relatively selective inhibitor for iNOS, equally suppressed nitrite in urine and renal tissue. Glomerular ICAM-1 expression and macrophage infiltration were reduced by L-NAME, but not by AG. Expression of ecNOS was significantly increased by L-NAME (0.91 +/- 0.08, P < 0.0001 versus NTN), but slightly by AG (0.18 +/- 0.04). AG significantly and L-NAME slightly attenuated the glomerular damage at day 4. In conclusion, suppression of iNOS prevents glomerular damage in the early stage of NTN. Treatment by L-NAME reduces macrophage infiltration by suppression of ICAM-1 expression, which may be explained by an increase in ecNOS expression.     

Westernized food habits and concentrations of serum lipids in the Japanese

It has recently been reported that there exists a new 'RING-finger' protein family among the zinc-finger (Zf) proteins. Previously, we had isolated the mouse Mel-18 cDNA (mMel-18) encoding the nuclear RING-finger protein that exhibits an ability to bind to a nonspecific DNA column. Here, we have isolated and characterized the human Mel-18 cDNA (hMel-18) using the mMel-18 cDNA as a probe. The deduced hMel-18 protein contains 344 amino acids (38 kDa) with a RING-finger motif, a helix-loop-helix (HLH)-like structure and a Pro/Ser-rich region. The hMel-18 gene is conserved among vertebrates. Its mRNA is highly expressed in placenta, lung and kidney, but the level is low in liver, pancreas and skeletal muscle. Using in situ hybridization, we mapped hMel-18 to band q22 of chromosome 12. It is possible that the Mel-18/bmi-1 gene family represents a mammalian homologue of the Drosophila polycomb gene group.     

Clonal change of HTLV-1 infected lymphocytes before onset of adult T-cell leukemia/lymphoma

A 73-year-old HTLV-1 infected male developed overt ATL following 3-years observation, and the clonality of HTLV-1 infected cells changed before overt ATL onset. 10 micrograms of DNA, extracted from mononuclear cells was digested with PstI, and the clonal proliferation of HTLV-1 infected cells was examined by Southern blotting with LTR probe. 4 bands were observed 3 years prior to ATL onset, and 2 different bands were detected 2 years and 6 months later. This suggests that in some ATL cases, the clonality of monoclonally proliferated HTLV-1 infected cells may be changeable before overt ATL onset.     

Fibrinolysis, antithrombin III, and protein C in neonates during cardiac operations

Fibrinolysis and coagulation were studied in 10 neonates undergoing cardiac operations for congenital heart defects. Coagulation was activated during cardiopulmonary bypass as evidenced by highly increased prothrombin fragment 1 + 2 levels compared with preoperative values. Prothrombin fragment 1 + 2 levels remained elevated until postoperative day 3. Unlike coagulation, fibrinolysis was not activated during cardiopulmonary bypass but did show late activation on postoperative day 3, as evidenced by elevated levels of the fibrin degradation product D-dimer. Lack of fibrinolytic activation during bypass and its appearance on postoperative day 3 were partly explained by changes observed in tissue plasminogen activator and its inhibitor. During bypass, levels of tissue plasminogen activator and its inhibitor increased by 3.4-fold and 3.2-fold, respectively. In the postoperative period, levels of plasminogen activator inhibitor normalized rapidly whereas tissue plasminogen activator remained elevated, resulting in late fibrinolytic activation on postoperative day 3. In accordance with elevated prothrombin fragment 1 + 2, platelet count, antithrombin III, protein C, prothrombin, and factor VII were decreased on postoperative day 2, indicating ongoing consumptive coagulopathy. Nine patients had antithrombin III and six had protein C levels below age-specific normal ranges, consistent with an acquired deficiency state. Three had central venous thrombosis by postoperative day 4 or 5. In all three, thrombosis was preceded by antithrombin III deficiency, protein C deficiency, and highly elevated plasminogen activator inhibitor (3.7 to 37 times the mean of the other patients) on postoperative days 1 to 3. In conclusion, cardiopulmonary bypass in neonates caused rapid and profound alterations in the coagulation and fibrinolytic systems and initiated consumptive coagulopathy lasting until at least postoperative day 3. Thrombophilic abnormalities in antithrombin III, protein C, and fibrinolysis were frequently found and were associated with serious thrombotic complications.     

Kinetic trapping of oxygen in cell respiration

Cell respiration in eukaryotes is catalysed by mitochondrial enzyme cytochrome c oxidase. In bacteria there are many variants of this enzyme, all of which have a binuclear haem iron-copper centre at which O2 reduction occurs, and a low-spin haem, which serves as the immediate electron donor to this centre. It is essential that the components of the cell respiratory system have a high affinity for oxygen because of the low concentration of dissolved O2 in the tissues; however, the binding of O2 to the respiratory haem-copper oxidases is very weak. This paradox has been attributed to kinetic trapping during fast reaction of O2 bound within the enzyme's binuclear haem iron-copper centre. Our earlier work indicated that electron transfer from the low-spin haem to the oxygen-bound nuclear centre may be necessary for such kinetic oxygen trapping. Here we show that specific decrease of the haem-haem electron transfer rate in the respiratory haem-copper oxidase from Escherichia coli leads to a corresponding decrease in the enzyme's operational steady-state affinity for O2. This demonstrates directly that fast electron transfer between the haem groups is a key process in achieving the high affinity for oxygen in cell respiration.     

Pathogenetic aspects of the L-arginine-NO metabolic pathway in arteriosclerosis and possible therapeutic aspects

A yearly pattern in the occurrence of uterine cervical cancer (UCC), obtained from cytological examinations reported as type V (cases concluding a malignant alteration), has been previously shown for data obtained in the Monterrey Metropolitan Area (state of Nuevo Leon, Mexico) for a span of 10 years (1978-1987), with a peak of relative incidence in the month of February being high stable for consecutive years. With the aim of extending and validating those results, we analyzed the monthly totals of positive detected cases of UCC in the states of Nuevo Leon, Chihuahua, Coahuila, and Tamaulipas (covering most of Northern Mexico) during the same period. To eliminate bias due to the seasonal variation in the number of screening smears, data were first expressed in relation to the number of cytological examinations done the same month. The least-squares fit of a 1-year cosine curve to the data of relative incidence in the four states reveals a statistically significant yearly pattern (p = .008), with a maximum of relative incidence in February almost double that during the rest of the year. Results indicate that the relative incidence of UCC is higher than the yearly average during the winter, with secondary peaks in May and October. In view of the nonsinusoidal waveform in the incidence of UCC, we undertook a multiple-component analysis, allowing several cosine functions to be simultaneously fitted to the data. Results indicate that the yearly pattern in the relative incidence of UCC can be represented by a model that includes two components with periods of 12 and 4 months (p = .004). The same model can be documented as statistically significant independently for each of the four states. These results, summarizing over 2200 positive cases of UCC detected in more than 1,100,000 screening smears, are in full agreement with those found previously for part of the state of Nuevo Leon and reveal a highly stable and predictable yearly pattern of variation in the relative incidence of UCC in Northern Mexico.     

Effects of some calcium-related agents on the protoplast transfection of Lactobacillus casei with phage PL-1 DNA

An audit of the treatment procedures routinely adopted by maxillofacial and oral surgeons for the removal of impacted third molars under general anaesthesia was undertaken in South Africa. Most maxillofacial and oral surgeons agree on the method of bone removal, the prescribing of antibiotics, analgesic agents and mouthwashes, the suturing of the incision wound and the post-operative review of patients. The results were compared to a similar study undertaken by Falcon and Roberts (1992) in the UK. With the exception of the method of bone removal, maxillofacial and oral surgeons in both groups share a similar approach to the treatment procedures adopted in the removal of impacted third molars. Some variability, however, existed in both studies with regard to the use of intra-operative local anaesthetic agents, the administration of peri-operative steroids and the use of non-steroidal anti-inflammatory agents.     

Human papillomavirus-specific serologic response in vulvar neoplasia

We describe a case of positional dyspnea due to compression of the tracheobronchial tree by an extensive thoracic aneurysm. In a 77-year-old woman with long-standing systemic hypertension, intermittent anterior chest pain gradually developed over several years. She had no history of asthma or thoracic trauma. She was admitted to our hospital because of sudden, severe shortness of breath. The breathlessness was markedly worse when she lay on her back or on her right side. On physical examination, she was in acute respiratory distress with cyanosis, severe hypertension (180/110 mmHg), tachycardia, and inspiratory stridor. A chest X-ray film showed loss of volume and nearly complete radiopacity of the left hemithorax. Arterial blood gas analysis revealed an arterial oxygen partial pressure of 54.8 mmHg, a carbon dioxide partial pressure of 39.8 mmHg, and an oxygen saturation of 84.5 percent on room air. Computed tomographic examination of the thorax showed dilation of the aortic arch and descending aorta, and marked compression of the trachea and the left main bronchus. Examination with a fiberoptic bronchoscope revealed extrinsic compression of the trachea just proximal to the carina. The patient's symptoms stabilized. However, she did not undergo surgery because of her age and because of the size of the aneurysm. She died due to rupture of the aneurysm.     

Fabrication of GaAs quantum wire structure using metal organic molecular beam epitaxy

GaAs quantum wires (100*20 nm/sup 2/) buried in AlAs layers have been successfully fabricated using metal organic molecular beam epitaxy (MOMBE) for the first time. The underlying growth mechanism is that, under appropriate As/sub 4/ pressure in MOMBE, GaAs preferentially grows only on the sidewalls of the patterned