Cloning and mRNA expression of human unconventional myosin-IC. A homologue of amoeboid myosins-I with a single IQ motif and an SH3 domain.

The complete deduced amino acid sequence and mRNA expression of human unconventional myosin-IC (HuncM-IC) are described. Sequencing of overlapping cDNA clones reveals a message of 4666 nucleotides with a single open reading frame predicted to encode a 127 kDa protein of 1109 amino acids. HuncM-IC is composed of three discrete regions: a characteristic N-terminal myosin head with predicted actin and ATP-binding sites; a neck domain with an "IQ motif", predicted to bind a single light chain; and a C-terminal tail with a putative membrane-binding site. In addition, the tail contains an src-homology 3 domain. The presence of a single IQ motif and an src-homology 3 domain is reminiscent of "long-tailed" myosins-I from amoeboid organisms, a supposition confirmed by multiple sequence alignment. Northern blot analysis of human tissues shows that HuncM-IC is ubiquitously expressed, with the highest levels in kidney, prostate, colon, liver and ovary. The results show that "amoeboid" myosins-I are not restricted to amoeboid organisms, rather they are expressed in the metazoa as well.

Pulmonary hypertension caused by Graves' thyrotoxicosis: normal pulmonary hemodynamics restored by (131)I treatment.

We describe a case of pulmonary hypertension, initially thought to be idiopathic, which resolved after treatment of Graves' hyperthyroidism. Results of pulmonary artery catheterization before and after treatment are reported, and the effects of thyrotoxicosis on hemodynamics and pulmonary function are briefly reviewed. Possible mechanisms for development of pulmonary hypertension caused by hyperthyroidism include pulmonary vascular endothelial dysfunction or damage because of autoimmunity or the high cardiac output state, or increased metabolism of intrinsic pulmonary vasodilators.

Diffuse pulmonary arteriovenous malformations: characteristics and prognosis.

OBJECTIVE: To study the clinical characteristics and prognosis of patients with diffuse pulmonary arteriovenous malformations (AVMs). DESIGN: Retrospective chart review of all patients (n = 16) with diffuse pulmonary AVMs seen at Yale New Haven Hospital, Johns Hopkins Hospital, and St. Michael's Hospital. Up-to-date follow-up information was obtained in all living patients. RESULTS: All patients were severely hypoxic. Neurologic complications (stroke or brain abscess) had occurred in 70% of patients by the time of diagnosis. During the follow-up period (mean, 6 years), three patients died and two others developed new neurologic complications. One of the deaths occurred perioperatively during lung transplantation. All patients underwent transcatheter embolotherapy of any large pulmonary AVMs. A selected group underwent pulmonary flow redistribution, a novel technique. Oxygenation did not improve significantly with embolotherapy of the larger AVMs, but there was a small significant improvement in those patients who underwent pulmonary flow redistribution. The majority (85%) of the living patients are currently working or studying full-time. CONCLUSIONS: Patients with diffuse pulmonary AVMs are at increased risk of neurologic complications. Transcatheter embolotherapy does not significantly improve the profound hypoxia, but it may reduce the risk of neurologic complications. Antibiotic prophylaxis is recommended for bacteremic procedures to prevent brain abscess. These patients can live for many years and lead productive lives. We do not recommend lung transplantation because survival with disease is difficult to predict and we have observed a perioperative transplant death.

Embolotherapy of large pulmonary arteriovenous malformations: long-term results.

BACKGROUND: The purpose of this study was to document the long-term results of transcatheter embolotherapy of large pulmonary arteriovenous malformations (PAVMs). METHODS: From a data base of 221 consecutive patients with PAVMs treated by embolotherapy between 1978 and 1995, 45 patients with 52 PAVMs, supplied by feeding arteries 8 mm in diameter or larger, were selected for a retrospective investigation. RESULTS: Of 45 patients with 52 large PAVMs, 38 patients (84%) with 44 PAVMs (85%) were cured by the first embolotherapy (mean follow-up, 4.7 years). Acute periprocedural complications included self-limited pleurisy (31%), angina secondary to air embolus (2%), and paradoxical embolization of a device during deployment (4%). None of these events led to short- or long-term sequelae. Seven patients (16%) had persistence of the PAVM attributable to either recanalization (n = 4) or interim accessory artery growth (n = 3). Two of these patients presented with ischemic stroke several years after the initial treatment. Persistent PAVMs (n = 8) were retreated successfully by a second procedure (n = 7), or a third procedure (n = 1) (mean follow-up, 5.9 and 5.3 years, respectively). CONCLUSIONS: Embolotherapy of large PAVMs results in permanent occlusion in an overwhelming majority of patients. Continued patency due to recanalization or accessory artery growth is easily detected and treated.

Airway isocyanate-adducts in asthma induced by exposure to hexamethylene diisocyanate.

OBJECTIVES: The clinical features, airway histology, and detection of hexamethylene diisocyanate (HDI) protein adducts in endobronchial biopsies from a patient with HDI asthma are described. METHODS: Isocyanate asthma was diagnosed by history, methacholine challenge, and workplace HDI challenge. Bronchoscopy was performed 24 h after challenge and immunohistochemical staining was performed. RESULTS: Airway biopsies obtained at bronchoscopy demonstrated inflammatory changes typical for asthma, including increased airway eosinophils and T cells. Immunohistochemical staining with specific anti-HDI antibodies demonstrated the presence and localization of HDI adducts in human bronchial biopsies. CONCLUSIONS: These studies confirm epithelial exposure to HDI following workplace challenge and demonstrate the feasibility of detecting and localizing isocyanate adducts in human lung tissue. Identifying and characterizing the airway macromolecules to which isocyanates bind in vivo are probably crucial to the understanding of how isocyanates cause sensitization and asthma. The ability to detect isocyanate adducts may also help characterize isocyanate exposure patterns and exposure-disease relationships.

[The influence of nCPAP therapy on the autonomic nervous system dysfunction in OSA patients]. / Influenta terapiei nCPAP asupra sistemului nervos autonom la pacientii cu SAOS.

UNLABELLED: Obstructive sleep (OSA) can induce severe arrhythmias, including prolonged periods of asystole and heart block. Heart rate variability (HRV) has gained importance as a technique employed to explore the autonomic nervous system (ANS) which plays an important role in arrythmogenesis. AIMS: Our aim was to investigate nocturnal HRV by spectral analysis of RR intervals before and after continuous positive airway pressure (nCPAP) therapy. METHODS: To confirm the relation between OSA and ANS dysfunction, we prospectively investigated ANS function in 24 patients (18 males, mean age 53 years) with moderate or severe OSA. Overnight polysomnography was performed before and after nCPAP therapy. We analyzed apnea/hypopnea index (AHI), desaturation index, mean arterial oxygen saturation, mean and standard deviation (SD) for nocturnal HRV triangular index and pNN50 before and after initiating CPAP treatment. RESULTS: AHI decreased markedly from 51 to 3 events/h, desaturation index decreased from 45.9 to 3.62 events/h, and mean arterial oxygen saturation improved from 92.15% to 94.8%. Nocturnal HRV triangular index decreased from 18.3 to 12.85 as well as nocturnal pNN50 in all patients after initiating nCPAP therapy, suggesting that efficient nCPAP therapy may restore nocturnal autonomic defects, characteristic of severe and moderate OSA, as proven in previous studies. CONCLUSIONS: Abnormalities in cardiovascular variability may be implicated in the subsequent development of cardiovascular diseases in patients with OSA. These results suggest that impaired ANS function is present in patients with OSA and can be improved by successful nCPAP therapy.

[Organic psychosyndrome and sleep apnea. Transdermal nicotine--a new therapy concept?]. / Hirnorganisches Psychosyndrom und Schlafapnoe. Transdermales Nikotin--ein neues Therapiekonzept?

We examined 11 patients (10 female, 1 male) of 73 to 79 years of age suffering from organic psychosyndrome (HOPS), using the apnoea screen system MESAM IV (1) and APNOE-SCREEN I. All examined patients had a sleep related disordered breathing (SBAS) with apnoea index (AI) between 10 and 52 (P/h). 3 patients (2 female, 1 male) had an increasing apnoea index under medication of theophyllin 375 mg/d. these theophyllin-nonresponsive patients received transdermal Nicotin in a concentration of 21 mg/d (during the night). The apnoea index decreased not significantly, while the tiredness was reduced significantly by 42.9%, the confusion by 40% and the nightly restlessness by 50%.

Pulmonary arteriovenous malformations: diagnosis and transcatheter embolotherapy.

The recent long-term studies from England, France, and the Netherlands, as well as our own, indicate that transcatheter embolotherapy is definitive treatment for PAVM. More recently, Puskas et al have questioned transcatheter embolotherapy as a primary treatment for patients with PAVM (4,56). Their opinion was based on two recurrences among five patients treated with transcatheter embolotherapy. It is not clear why one of the late recurrences in the series by Puskas et al happened, and the other recurrence could have been dut to early deflation of the balloon. Nevertheless, we believe that the collective experience in the larger series reporting on transcatheter embolotherapy of PAVM supports the use of embolotherapy as a primary modality of treatment. Because many patients have bilateral pulmonary malformations and many pulmonary malformations will grow with time, repeated surgical intervention is not ideal therapy. The recurrence rate of 8% reported by Remy et al using coils, and 2% reported by Pollak et al using balloons and coils supports our contention that transcatheter embolotherapy is durable and should be the initial treatment. Also, recurrences are easily retreated by transcatheter embolotherapy with durable results (54). We favor detachable balloons over coils for occluding PAVMs because immediate cross-sectional occlusion of the segmental artery is obtained in a position that preserves the most normal branches. The necessity for repeated introduction of coils, when using the coil method, contributes to longer procedure times with an increased risk of air introduction and, in our experience, a greater risk of postprocedure pleurisy. At the same time, we appreciate that approximately 70% of PAVMs can be occluded equally well with balloons or coils. We also believe that coils have unique advantages over balloons in specific anatomic situations including oversized arteries (where coils are the only option) and for occlusion of the aneurysm of a PAVM. As with all forms of embolotherapy, the interventionalist is best served by having more than one option of treatment, which for PAVM includes both balloons and coils. In summary, PAVMs are effectively managed by means of transcatheter embolotherapy. This therapy has been demonstrated to be safe and durable. Careful technique with modifications depending on the angioarchitecture of the PAVM is required. Patients with PAVMs require follow-up at 1 month and 1 year. While observations documenting serial growth of small PAVMs are somewhat limited, there is published evidence to support their growth with time (35,36). Because of these reports and our unpublished observations, we believe that patients with treated PAVM need long-term follow-up every 5 years to detect growth of small PAVMs that will ultimately reach a size where they may cause paradoxical embolization and stroke (1).

Identification and overlapping expression of multiple unconventional myosin genes in vertebrate cell types.

Myosin diversity in the human epithelial cell line Caco-2BBe, the porcine epithelial cell line LLC-PK1 (CL-4), human peripheral blood leukocytes, and human liver was analyzed. PCR amplification yielded 8-11 putative myosins (depending on the cDNA source) representing six distinct myosin classes. Analysis of clones obtained by hybridization screening demonstrated that the original PCR products correspond to bona fide myosins, based on the presence of sequences highly conserved in other myosins. RNase protection analysis confirmed mRNA expression of 11 myosins in Caco-2BBe cells. Immunoblot analysis showed that at least 6 myosin immunogens are expressed in Caco-2BBe cells. The results reveal the existence of at least 11 unconventional human myosin genes, most of which are expressed in an overlapping fashion in different cell types. The abundance of myosins suggests that the myosin I vs. myosin II paradigm is inadequate to explain actin-based cellular motility.

Human myosin-IXb, an unconventional myosin with a chimerin-like rho/rac GTPase-activating protein domain in its tail.

The full-length primary structure and expression profile of a novel unconventional myosin heavy chain, human myosin-IXb, is described. The primary structure of this myosin predicts a 229 kDa protein that together with its recently described rat homolog, myr 5, is the ninth class of myosins to be identified. In comparison to skeletal muscle myosin-II, the myosin-IXb 'head' has two unusual features: a novel N-terminal domain of 140 amino acids, which includes a 60 amino acid extension, and a large insertion of 126 amino acids in the putative actin-binding site. The 'neck' contains four tandemly repeated IQ motifs, suggesting that this myosin may have four associated light chains. The 'tail' contains a region similar to regions found in the chimerins, with a putative zinc and diacylglycerol binding domain, homologous to the regulatory domain of protein kinase C and a putative GTPase-activating protein (GAP) domain of the rho/rac family of ras-like G-proteins. Northern blot analysis of 16 different human tissues revealed an approximately 8 kb transcript that is most highly expressed in peripheral blood leukocytes, with somewhat lower levels of expression in thymus and spleen, suggesting that myosin-IXb is most abundant in cells of myeloid origin. Myosin-IXb was also expressed in a number of other tissues at significantly lower levels. Analysis of myosin-IXb protein expression, using a tail-domain directed antibody, was performed in HL-60 cells, a human leukocyte cell. Myosin-IXb expression increases by 4- to 5-fold upon induced differentiation of these cells into macrophage-like cells. The localization of myosin-IXb is also altered upon differentiation. In undifferentiated HL-60 cells, myosin-IXb colocalizes with F-actin in the cell periphery, while in differentiated cells its localization becomes more cytoplasmic, with the highest levels in the perinuclear region.

Primary pulmonary hypertension in association with human immunodeficiency virus infection. A possible viral etiology for some forms of hypertensive pulmonary arteriopathy.

Recent reports have suggested a possible association between HIV-1 infection and primary pulmonary hypertension (PPH), but most of the patients described to date have either had acquired immunodeficiency syndrome (AIDS) with concurrent lung infections or have administered Factor VIII intravenously for hemophilia. We report three human immunodeficiency virus type 1 (HIV-1)-positive homosexual white males with clinical and hemodynamic diagnoses of PPH. None of the patients had any opportunistic lung infections or other pulmonary pathology, nor were they hemophiliacs. They had no histories of intravenous drug use. Lung tissue from two of the patients revealed hypertensive arteriopathy consistent with PPH and no other pulmonary pathology. Attempts at localizing HIV-1 infection to the vascular endothelium with electron microscopy, immunohistochemistry, DNA in situ hybridization, and polymerase chain reaction techniques did not reveal direct pulmonary artery infection with the virus. These data and the finding of tubuloreticular structures on electron microscopy suggest that HIV-1 may play a role in the pathogenesis of these cases of PPH through mediator release associated with HIV-1 infection rather than by direct endothelial infection.