Functional consequences and intracoronary localization of alpha-adrenergic stimulation of the canine coronary circulation

Although alpha-adrenergic stimulation can increase coronary vascular resistance, it remains unknown whether the vasoconstriction can override intrinsic coronary regulatory influences to produce ischemia. Methoxamine, 2 to 4 mg, was infused into the circumflex coronary artery of 23 chloralose-anesthetized open chest dogs, and resulted in a 68% increase in coronary vascular resistance. The functional consequence of this increased coronary vascular resistance was assessed by gated radionuclide ventriculography and ST-T wave changes on the electrocardiogram. In six dogs (Group I), aortic pressure changed trivially (less than 5 mm Hg) to allow distinction between direct effects of the flow reduction and indirect effects of increased aortic pressure. In this group, coronary blood flow decreased 33% from a control value of 44 +/- 10 ml/min (p less than 0.001) and left ventricular ejection fraction decreased from 0.54 +/- 0.12 to 0.46 +/- 0.10 (p less than 0.025). In eight dogs (Group II) in which aortic pressure increased by more than 5 mm Hg, left ventricular ejection fraction decreased from 0.46 +/- 0.07 to 0.39 +/- 0.09 (p less than 0.002). Pressure gradients were measured between the aorta and a distal coronary artery branch to calculate small and large vessel resistances separately in four other dogs (Group III). The resistance of small coronary arteries accounted for 92% of the total increase in coronary vascular resistance produced by methoxamine. In five other dogs (Group IV), intracoronary methoxamine, 2 mg, produced ST-T wave changes suggestive of ischemia as it increased coronary vascular resistance by 33%.(ABSTRACT TRUNCATED AT 250 WORDS)

Doxorubicin/vinblastine and doxorubicin/cyclophosphamide combination chemotherapy by continuous infusion

Fifty-two patients received one of two doxorubicin (DOX)-based admixtures; DOX plus cyclophosphamide (CTX) or DOX plus vinblastine (VBL) administered as a continuous 24-hour infusion for protracted periods. Compatibility and stability of the two-drug admixture was established for a minimum of 7 days. Twenty patients on the DOX/CTX admixture were infused for a median of 20 days (range, 7-56 days). DOX/VLB was infused in 32 patients for a median of 18 days (range, 5-48 days). Dose limiting toxicity was leukopenia observed in 14/52 patients; 4/20 on DOX/CTX and 10/32 on DOX/VLB. Additional toxicities observed included stomatitis (15%) and subclavian vein thrombosis (23%). Tumor responses were observed in 11 patients, including 6/13 breast cancer; 2/2 hepatoma; 2/4 sarcoma and 1/1 ovarian cancer. Responses were relatively short-lived and no responses were noted in known anthracycline resistant tumors. Admixtures of chemotherapeutic agents represents a novel, but feasible, mechanism for delivery of multiple drugs with an infusion schedule and can be considered for Phase III comparative clinical trials.

Pulmonary vascular obstruction in the adult respiratory distress syndrome

Pulmonary vascular obstruction is most likely to occur in patients with the severest form of ARDS. Obstruction has been ascribed to fibrin thrombosis and to activation of the blood coagulation system, both well-documented in ARDS. The obstruction has been postulated to occur in two stages during post-traumatic ARDS: an initial transient pulmonary vasoconstriction, attributable to platelet and leukocyte aggregation and the release of vasoactive substances; and, two to five days post injury, a more malignant "delayed microembolism" stage, attributable to the development of protein-rich edema and fibrin deposition in the lungs. Bedside balloon occlusion pulmonary angiography, in a single exposure, allows identification of intraluminal filling defects and occlusions of arteries greater than or equal to 1.0 mm in diameter, irregularity and decreased filling of side branch arteries 0.5 to 1.0 mm in diameter, and decreased filling of the pulmonary microvascular background. Plain radiography findings correlate poorly with angiography results, but the mortality rate of patients who exhibit angiographic evidence of obstruction is twice as high as it is in patients with normal angiography.

Interpretation of pulmonary artery wedge pressure and pullback blood gas determinations during positive end-expiratory pressure ventilation and after exclusion of the bronchial circulation in the dog

Left atrial pressure (LAP) and pulmonary artery wedge pressure (PWP) were measured at different heights during graded increases in positive end-expiratory pressure (PEEP). Six healthy anesthetized dogs were placed in lateral decubitus positions with a balloon-tipped pulmonary artery catheter inserted in each lung. PWP in the gravitationally superior lung overestimated LAP at 15 and at 20 cm H2O PEEP (p less than 0.05). PWP in the dependent lung was virtually identical to LAP at all degrees of PEEP. Wedge blood could be aspirated through the distal lumen of the pulmonary artery catheters during balloon inflation at all degrees of PEEP except for 3 attempts. PCO2 in wedge blood in both the nondependent and dependent lungs at all degrees of PEEP was consistently lower than PCO2 in arterial blood (p less than 0.05). Wedge blood was arterialized, i.e., oxygen saturation greater than 95%, in all but 4 specimens. Surgical elimination of the bronchial artery supply to the lung in 3 dogs did not affect PWP or blood gas measurements. We conclude that in this animal model: (1) the tip of a pulmonary artery catheter must be below the level of the left atrium, Zone III location, to accurately reflect LAP at high degrees of PEEP; (2) arterialization of wedge blood samples does not guarantee that PWP reflects LAP; (3) bronchial artery blood supply does not affect PWP or wedge blood gas measurements, even at high degrees of PEEP.

Cross-sectional imaging of silent pulmonary venous anomalies

An overview of the forms of partial anomalous pulmonary venous connections (PAPVC) and a discussion of the role of computed tomography (CT) in diagnosing this anomaly are offered. Although angiography remains the most sensitive technique for detection of anomalous pulmonary veins and other cardiac anomalies, the increased use of CT over the past decade has probably resulted in the detection of PAPVC that otherwise might have been missed. In the case of asymptomatic PAPVC, CT may provide positive identification and obviate the need for further studies.

Protracted low-dose cisplatin infusion in advanced colorectal cancer

Protracted, 24-hour, continuous-infusion cisplatin at a dose rate of 5 mg/m2/day was administered to 25 patients with advanced measurable colorectal cancer. All patients had previously received 5-FU administered on the same schedule. Sixteen patients received the infusion for greater than or equal to 14 days and were considered evaluable for response assessment. No patient achieved a response.

Vinblastine plus cisplatin in advanced non-small cell lung cancer: lack of advantage for vinblastine infusion schedule

We have evaluated 31 patients with advanced non-small cell lung cancer treated by short-term 5-day vinblastine infusion combined with bolus cisplatin. Nine of 31 patients (29%) had partial and complete responses. Although five of nine (55%) of the responders were alive at greater than or equal to 1 year, three of the 31 patients experienced drug-related mortality. Our experience, as well as a review of previously reported trials in the literature, suggests that the infusion schedule of vinblastine offers no advantage over the bolus schedule.

Two calcium-sensitive spike after-hyperpolarizations in visceral sensory neurones of the rabbit

Intracellular recordings were made from rabbit nodose neurones in vitro. Two temporally distinct spike after-hyperpolarizations (a.h.p.s) were identified in a subpopulation of C-type neurones. The fast a.h.p. after a single spike lasted no longer than 500 ms, while the slow a.h.p. persisted for seconds. Both a.h.p.s. were increased in amplitude in low K+ (0.56 mM) solutions and decreased in amplitude in high K+ (11.2 mM) solutions, and both were reversed at hyperpolarized membrane potentials. The slow a.h.p. was reduced in low Ca2+ (0.22 mM), in the presence of Ca2+ antagonists (Ni2+, 1 mM; Cd2+, 100 microM; or Co2+, 1 mM) and was enhanced in tetraethylammonium (5 mM). In approximately half of the cells tested, the fast a.h.p. was reduced in low Ca2+ and in the presence of the Ca2+ antagonists. In the remaining cells the fast a.h.p. was insensitive to these procedures. Prostaglandin (PGE1, 1-10 micrograms/ml) reduced the slow a.h.p. in all cells tested. Neither the Ca2+-sensitive nor the Ca2+-insensitive fast a.h.p. was affected by the prostaglandin. It is concluded that there is a subpopulation of C-type nodose neurones possessing a slow a.h.p. which is due to a Ca2+-dependent K+ current. This subpopulation of neurones can further be divided on the basis of the presence of a Ca2+-sensitive fast a.h.p. Furthermore, PGE1 pharmacologically separates the fast and slow a.h.p.s by selectively blocking the slow one. The blockage by the PGE1 is most probably not due to a reduction in Ca2+ influx.

The drawing prism

Artists using conventional computer graphic input devices cannot produce the same visual effects which they can with traditional tools and media. The drawing prism is a new device which allows people to draw or paint directly into a frame buffer, using brushes, their hands, or a variety of other objects. These objects can be manipulated to achieve continuously adjustable line qualities and textures, in the same ways that artists have traditionally used their hands and tools.The device uses one face of a large transparent prisms as a drawing surface. A video camera views that surface from an angle such that it can only image the points of optical contact between drawing tools and the surface. These images are digitized and processed in real time so as to build up a drawing as the tools are moved along the surface. A layer of transparent liquid helps tools make optical contact with the drawing surface. Any light colored object can thus be used as a drawing tool.Details of the current implementation are provided along with suggestions for improving its resolution. Combinations of visual effects previously restricted to either traditional media or computer graphics are described and illustrated.

Randomized trial of estrogen vs. tamoxifen therapy for advanced breast cancer

Forty-three postmenopausal females with advanced breast cancer were studied in a prospective comparative trial of estrogen vs. an anti-estrogen (tamoxifen) therapy with a crossover to the alternative hormone with progressive disease. Ten of 19 patients (53%) responded to primary tamoxifen therapy and six of 24 (25%) responded to primary estrogen therapy. Crossover responses were observed in seven of 19 (37%) on the secondary tamoxifen therapy and in two of 10 (20%) on secondary estrogen therapy, and were not related to the response to the primary hormonal maneuver. Responses were related to the presence of estrogen receptor protein (ERP), particularly for tamoxifen therapy, although responses were observed in three of six ERP negative patients receiving estrogen and in seven of 25 (28%) of patients with an unknown ERP status. Complications were observed in 35 instances with estrogen therapy and in only five instances with tamoxifen therapy. Initial hormonal therapy with tamoxifen in postmenopausal patients with advanced breast cancer and ERP status positive or unknown is superior to primary estrogen treatment. Secondary therapy and response to estrogen or tamoxifen is not necessarily predicted by the initial hormone response, and crossover to the alternative therapy is generally indicated.

Supplementary tissue-core histology from fine-needle transthoracic aspiration biopsy

Biopsies of 150 consecutive suspected lung cancers were performed with fine needles having circumferentially beveled tips that produced cytology and tiny tissue cores suitable for histology. Visible tissue cores were aspirated in 92% (n = 138) and histologic diagnoses were obtained in 72% (n = 108). There were 118 (79%) proven malignant and 27 (18%) proven benign lesions. Sensitivity and specificity of cancer diagnoses were 97% and 100%, respectively. Biopsy histology was the only positive cancer specimen in two biopsies (1.7%). Biopsy cytology was the only positive cancer specimen in 20 cases (17.2%). Biopsy cytology and histology agreed with the proven cell type in 71.8% and 78.6% of cancers, respectively. As expected, when large-cell undifferentiated carcinoma was regarded as a nonspecific cell type consistent with either poorly differentiated adenocarcinoma or poorly differentiated epidermoid carcinoma, biopsy-cell-type accuracy increased greatly. Specific benign diagnoses were obtained in 44% of the 27 biopsies of proven benign lesions: cytology (four), core histology (five), and bacteriology (nine). Simple and complicated pneumothorax occurred in 10% and 4% of biopsies, respectively. It was concluded that biopsy with fine, circumferentially beveled needles can produce useful histology to supplement biopsy cytology.

Asbestos-related pleural thickening: effect of threshold criteria on interpretation

Radiographic evidence of pleural thickening was evaluated in 1,216 shipyard workers (high-risk group) and 214 executives (low-risk group) and classified according to two threshold levels: low (any detectable thickening) and high (thickening less than or equal to 2 mm excluded). Results were markedly different, affecting the low-risk group more than the high-risk group. Changing from the high to the low threshold markedly increased pleural findings and scores as well as inter-reader correlation while reducing both differences between risk groups and detection of additional findings on supplementary oblique views. When data on prevalence and extent of pleural thickening were combined, differences between risk groups were maximized; however, when only prevalence was considered, such differences were minimized, particularly with a low threshold. These findings indicate that different or ambiguous threshold criteria produce divergent results in screening surveys for asbestos-related disease. The authors recommend that explicit minimal pleural threshold criteria be adopted.

Septic bursitis in systemic lupus erythematosus

Septic olecranon bursitis developed in three patients with systemic lupus erythematosus. Although promptly treated with systemic antibiotics, the clinical course in two patients became prolonged and eventually required bursectomy to eradicate the infection. The occurrence of septic bursitis was a manifestation of the general susceptibility of SLE patients to infections.

Respiratory distress syndrome with new considerations

To help maximize the salvage rate of patients with ARDS, radiologists must become active participants in a multidisciplinary team. A clear understanding of the nature of ARDS is a prerequisite. The authors briefly consider the pathogenesis of the syndrome and then discuss at length the usefulness of plain radiography and balloon occlusion pulmonary angiography in examining the patient with ARDS.

The pulmonary vascular lesions of the adult respiratory distress syndrome

Specimen arteriography, morphometry, and light and electron microscopy were used for examination of the pulmonary vasculature of 22 patients who died with the adult respiratory distress syndrome (ARDS), for the purpose of defining the lesions that contribute to pulmonary hypertension in this setting. The different lesions correlated with the duration rather than the cause of ARDS. Thromboemboli occurred in 21 patients, and macrothrombi found at autopsy correlated with the number of filling defects on antemortem angiography. Acute endothelial injury was documented ultrastructurally even in intermediate and late-stage patients. Fibrocellular intimal obliteration of arteries, veins, and lymphatics and infective vasculitis were prominent in those surviving beyond 10 days. In long-term survivors, tortuous arteries and irregularly dilated capillaries were striking features. Peripheral extension of vascular smooth muscle and a significant increase in the percentage of medial thickness of muscular arteries with duration of ARDS were noted. The pathogenesis and clinical significance of these lesions is discussed.

Mitomycin C: phase I study of a constant infusion ambulatory treatment schedule

Thirty patients received mitomycin C by constant infusion for 5 consecutive days (16 patients ) or for extended period by an ambulatory infusion pump (Cor-Med model) for 9 to 30 days (14 patients). The short-term 5-day infusions were delivered at dose rates of 2, 3, 4, 5 and 6 mg/m2/d with a cumulative dose of 15-50 mg. The protracted infusions were delivered at dose rates of 0.75-3 mg/m2/d with a cumulative dose of 21.6-65.2 mg. Marrow suppression was dose-limiting and occurred in 5/6 evaluable patients receiving more than 30 mg in the short-term infusion schedule and 8/10 evaluable patients receiving more than 20 mg in the protracted infusion schedule. The characteristics of the marrow suppression are that: a) thrombocytopenia precedes or is observed without concomitant leukopenia and b) the nadir day is delayed (WBC day 42, platelet day 36). Mitomycin C delivered by constant infusion leads to dose-limiting marrow toxicity at 20 to 30 mg cumulative dose depending upon the dose rate and duration of treatment. For short-term 5-day therapy, 3 mg/m2/d and for protracted therapy (up to 30 d) 0.75 mg/m2/d are the recommended dose rates for the constant infusion schedule.

Incremental value of oblique chest radiographs in the diagnosis of asbestos-induced pleural disease

To assess the value of oblique chest radiographs in the diagnosis of asbestos-related pleural disease, we identified 100 asbestos-exposed construction workers and provided separate interpretations of the postero-anterior (PA), left anterior oblique (LAO), and right anterior oblique (RAO) projections using the International Labour Office (ILO) system. We found that the LAO projection identified left-sided pleural thickening more effectively than the PA view and the RAO view improved diagnosis of right-sided disease comparably. Of 62 cases of bilateral pleural thickening, only 43 (68%) were diagnosed by the PA projection alone. The increased diagnostic efficiency of approximately 50% in identifying bilateral pleural thickening appears to justify the routine use of oblique chest films in screening asbestos-exposed populations. Since bilateral pleural thickening among asbestos-exposed workers is an indicator of significant asbestos exposure and increased risk of other asbestos-induced conditions, early detection of this abnormality can lead to interventions designed to reduce asbestos-related morbidity and mortality.

The pulmonary aspergilloses: three distinct entities or a spectrum of disease

The fungus Aspergillus can cause any of three clinical presentations--invasive aspergillosis, mycetoma, or allergic bronchopulmonary aspergillosis--or a disease process in which one of these entities overlaps with another process such as mucoid impaction, eosinophilic pneumonia, bronchocentric granulomatosis, "farmer's lung," or asthma. More than one form of the disease may be present at the same time; in addition, limited invasion may occur even in "noninvasive" forms of the disease, and the clinical and pathological aspects of allergic aspergillosis are often indistinguishable from those of unrelated allergic conditions. Thus it is no longer possible to compartmentalize the various types of pulmonary aspergillosis into exclusive forms of the disease; rather, the radiologist should be aware that various factors can modify the mode of growth of the fungus as well as the patient's response.

Disproportionate micromelia (Dmm): an incomplete dominant mouse dwarfism with abnormal cartilage matrix

This paper describes a new autosomal incomplete dominant dwarfism, disproportionate micromelia, which has been characterized genetically and phenotypically, and the cartilage of homozygotes, and heterozygotes has been examined by histochemical, immunofluorescence and biochemical methods. Homozygotes, which die at birth, are disproportionately short and have cleft palates. The heterozygotes appear normal at birth but beginning at 1 week of age dwarfism is apparent and increases during growth. Histochemical and biochemical analyses of the cartilage rudiments of homozygotes at day 18 of gestation demonstrate that the cartilage growth plate is disorganized and the matrix components, collagen and proteoglycan, are altered. Total collagen synthesis is reduced by approximately 30% and the amount of type II collagen is greatly reduced. By immunofluorescence staining with collagen antibodies, it appears that type II collagen is located primarily near the cell surface of chondrocytes but is poorly distributed throughout the remainder of the matrix. The amount of proteoglycan in the cartilage matrix is reduced by approximately 70% as determined by chemical analysis of hexosamines and by [35S]sulfate incorporation. Although the proteoglycans synthesized by the mutant are normal in size and in glycosaminoglycan composition, they were more easily extractable from the matrix than were normal cartilage proteoglycans. Heterozygotes had reduced cartilage matrix proteoglycan by histochemical methods, but the organization of the epiphyseal cartilage was not abnormal. These data suggest that a reduced or abnormal cartilage matrix is the cause of the dwarfism.

Results of exercise tests and prognosis in postinfarction patients below age 40

In a follow-up study (mean = 3.6 years) of 555 men under 40 years of age (mean = 35.7 years) who had recently suffered transmural myocardial infarction, 44 patients (7.9%) suffered cardiac death with an annual rate of 2.2%. In a bivariate analysis a significant correlation was found between cardiac death and work capacity (p less than 0.02), vessel involvement (greater than 50% stenosis), left ventricular impairment as evaluated by ventriculography (p less than 0.001) and heart volume enlargement (p less than 0.01). There was no significant correlation between the degree of ST-segment depression and ventricular premature depolarisation (during exercise test). Complex results from non-invasive approaches can identify groups with good and bad prognosis as effectively as invasive techniques.

Geographic wage indexing for CETA and Medicare

The tailoring of grants-in-aid to wage levels in the localities which receive them enjoys growing popularity among Federal policymakers; two ongoing programs illustrate the flexibility of this technique.

Malignant glomus jugulare tumor: a case with two unusual radiographic features

The computed tomographic demonstration of a glomus jugulare tumor with two unusual radiographic features--multiple pulmonary metastases and extension of the tumor into the cerebellopontine angle--is presented.

Fluid accumulation in preexisting pulmonary air spaces

Four patients with fluid accumulation in preexisting pulmonary air spaces are presented. Three patients developed fluid in an infected bulla; the fourth patient bled into a bulla. The slow spontaneous resolution of the accumulated fluid and the success of a conservative therapeutic approach are emphasized. The characteristic radiologic features of fluid-filled intrapulmonary air spaces are described and criteria for the differentiation from lung abscesses and empyemas are outlined.

Inhibition of purified wheat germ DNA dependent RNA polymerase by pyran copolymer

The inhibition of DNA and RNA polymerases in vitro by pyran copolymer has been shown to be related to its affinity for divalent cations. The present investigation was designed to explore further the nature of this inhibition using completely purified eukaryotic RNA polymerase II from wheat germ. Inhibition was determined as a function of divalent ion concentration and, as previously seen with less pure enzyme preparation, was greatest at low (Mn2+) and least at higher concentrations. No inhibition was observed at concentrations greater than 4.8 mM MgCl2 in the presence of 10 micrograms pyran/mL. The inhibition by pyran copolymer was exerted immediately unlike other polyanions, such as heparin and polynucleotides. This indicates that it stops RNA chain growth immediately as do known chelators of divalent cations. The size of pyran copolymer was shown to affect the extent of inhibition when different sized polymers were fractionated from a heterogenous single lot. However, when sized fractions were obtained from different lots we could not show a size-dependent inhibition. Although the mechanisms by which pyran copolymer exerts its biological effect is unknown, it may well be related to its association with cations. The inhibition of enzymes requiring these cations appears to be a sensitive method of observing such an association.

A study of variability in cytologic diagnoses based on pulmonary aspiration specimens

Reproducibility of cytologic diagnoses of malignancy and accuracy and variability of diagnoses of malignant cell types were assessed in a study of pulmonary aspirates from 100 patients. Original cytologic diagnoses were positive for 60 of the 80 patients who had malignancy (true-positive rate 75%). No false-positive diagnosis was made. Original cytologic diagnoses were negative for 15 of the remaining 20 patients (true-negative rate 75%). In "blindly" reviewing the slides, the pathologist who had made the original diagnoses (Observer A) and another pathologist (Observer B) confirmed the 60 original positive diagnoses. Observer A added four cases, Observer B 11 cases to the positive category. Cell types of original positive cytologic diagnoses and those of subsequent histologic diagnoses agreed for 23 of 33 malignancies (70%). Although two observers increased the proportion of positive cytologic diagnoses, the percentages of agreement with respect to histologic malignant cell types remained similar. For cytologic specimens, intraobserver agreement as to malignant cell types was 83% (50 of 60); interobserver agreement was 80% (48 of 60).

Compartment syndrome of the interosseous muscles: early recognition and treatment

A compartment syndrome of the interosseous muscles can be a challenging diagnosis as there is generally no neurovascular compromise to the digits involved. The most sensitive clinical sign is pain with passive motion at the metacarpal phalangeal joint of the involved digit. In this report, a 31-year-old man developed a compartment syndrome of the first, second, and third dorsal interosseous muscles following an injection of heroin in the "snuffbox" area. Compartmental tissue pressure measurements were 80, 75, and 55 mmHg respectively, and were a significant aid in the early diagnosis as well as management.