Regional regulation of focal adhesion kinase after concentric and eccentric loading is related to remodelling of human skeletal muscle.

AIMS: We assessed focal adhesion kinase (FAK) response to concentric (CON) vs eccentric (ECC) resistance training (RT) at two vastus lateralis (VL) sites, and the relationships between FAK, muscle protein synthesis (MPS) and morphological remodelling. METHODS: Six young males trained both legs unilaterally 3 times/week for 8 weeks; one leg performed CON RT, the contralateral performed ECC RT. Muscle biopsies were collected after training from VL mid-belly (MID) and distal (distal) sites at 0, 4, 8 weeks. Focal adhesion kinase content and activation were evaluated by immunoblotting. MPS was assessed by deuterium oxide tracer; morphological adaptations were evaluated by ultrasound and DXA. RESULTS: pY397-FAK 8 weeks levels were ~4-fold greater after ECC at the distal site compared to CON (P < .05); pY397FAK to total FAK ratio was greater in ECC vs CON at 4 (~2.2-fold, P < .05) and 8 weeks (~9-fold, P < .001) at the distal site. Meta-vinculin was found transiently increased at 4 weeks at the distal site only after ECC RT. ECC presented greater fascicle length (Lf) increases (10.5% vs 4%), whereas CON showed greater in pennation angle (PA) changes (12.3% vs 2.1%). MPS did not differ between exercise types or muscle sites at all time points. distal pY397-FAK and pY397-FAK/FAK values correlated to changes in Lf at 8 weeks (r = .76, P < .01 and r = .66, P < .05 respectively). CONCLUSION: Focal adhesion kinase phosphorylation was greater at 8 weeks after ECC RT and was muscle region-specific. FAK activity correlated to contraction-dependent architectural remodelling, suggesting a potential role of FAK in orienting muscle structural changes in response to distinct mechanical stimuli.

ACE inhibition modifies exercise-induced pro-angiogenic and mitochondrial gene transcript expression.

Skeletal muscle responds to endurance exercise with an improvement of biochemical pathways that support substrate supply and oxygen-dependent metabolism. This is reflected by enhanced expression of associated factors after exercise and is specifically modulated by tissue perfusion and oxygenation. We hypothesized that transcript expression of pro-angiogenic factors (VEGF, tenascin-C, Angpt1, Angpt1R) and oxygen metabolism (COX4I1, COX4I2, HIF-1α) in human muscle after an endurance stimulus depends on vasoconstriction, and would be modulated through angiotensin-converting enzyme inhibition by intake of lisinopril. Fourteen non-specifically trained, male Caucasians subjects, carried out a single bout of standardized one-legged bicycle exercise. Seven of the participants consumed lisinopril in the 3 days before exercise. Biopsies were collected pre- and 3 h post-exercise from the m. vastus lateralis. COX4I1 (P = 0.03), COX4I2 (P = 0.04) mRNA and HIF-1α (P = 0.05) mRNA and protein levels (P = 0.01) showed an exercise-induced increase in the group not consuming the ACE inhibitor. Conversely, there was a specific exercise-induced increase in VEGF transcript (P = 0.04) and protein levels (P = 0.03) and a trend for increased tenascin-c transcript levels (P = 0.09) for subjects consuming lisinopril. The observations indicate that exercise-induced expression of transcripts involved in angiogenesis and mitochondrial energy metabolism are to some extent regulated via a hypoxia-related ACE-dependent mechanism.

Successful pregnancy and cesarean delivery via noninvasive ventilation in mitochondrial myopathy.

We report a case study of a 22-year-old woman with mitochondrial thymidine kinase 2 deficiency and chronic respiratory failure due to severe neuromuscular weakness requiring noninvasive positive pressure ventilation (NIPPV) since 12 years of age. During pregnancy and cesarean delivery, she was successfully supported with NIPPV. A multidisciplinary team approach should be used in pregnant patients with these disorders with specific attention to management of pulmonary complications, selection of route of delivery, anesthesia, and analgesia.

Plasma vascular endothelial growth factor in acute mountain sickness.

STUDY OBJECTIVES: To investigate the hypothesis that an increase in circulating vascular endothelial growth factor (VEGF) occurs in mountaineers at high altitude, particularly in association with acute mountain sickness (AMS) and/or low hemoglobin oxygen saturation. DESIGN: : Collection of medical histories, AMS scores, plasma samples, and arterial oxygen saturation (SaO(2)) measurements from mountaineers at 1,500 feet (sea level) and at 14,200 feet. SETTING: Mount McKinley ("Denali"), AK. PARTICIPANTS: Sixty-six mountaineers. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Plasma VEGF at 14,200 feet was not increased in any group. In fact, plasma VEGF was significantly lower in subjects who did not develop AMS (53 +/- 7.9 pg/mL; mean +/- SEM; n = 47) compared to control subjects at sea level (98.4 +/- 14.3 pg/mL; n = 7; p = 0.005). Plasma VEGF at 14, 200 feet for subjects with AMS (62 +/- 12 pg/mL; n = 15) did not differ significantly from subjects at 14,200 feet without AMS, or from control subjects at sea level. Of a small number of subjects with paired specimens at sea level and at base camp (n = 5), subjects who exhibited a decrease in plasma VEGF at 14,200 feet were those who did not develop AMS. Neither SaO(2), prior AMS, AMS symptom scores, or acetazolamide use were correlated with plasma VEGF. CONCLUSIONS: Subjects at high altitude who do not develop AMS have lower plasma VEGF levels compared to control subjects at sea level. Plasma VEGF at high altitude is not elevated in association with AMS or hypoxia. Sustained plasma VEGF at altitude may reflect a phenotype more susceptible to AMS.

Inhalational anthrax: epidemiology, diagnosis, and management.

Anthrax, a disease of great historical interest, is once again making headlines as an agent of biological warfare. Bacillus anthracis, a rod-shaped, spore-forming bacterium, primarily infects herbivores. Humans can acquire anthrax by agricultural or industrial exposure to infected animals or animal products. More recently, the potential for intentional release of anthrax spores in the environment has caused much concern. The common clinical manifestations of anthrax are cutaneous disease, pulmonary disease from inhalation of anthrax spores, and GI disease. The course of inhalational anthrax is dramatic, from the insidious onset of nonspecific influenza-like symptoms to severe dyspnea, hypotension, and hemorrhage within days of exposure. A rapid decline, culminating in septic shock, respiratory distress, and death within 24 h is not uncommon. The high mortality seen in inhalational anthrax is in part due to delays in diagnosis. Classic findings on the chest radiograph include widening of the mediastinum as well as pleural effusions. Pneumonia is less common; key pathologic manifestations include severe hemorrhagic mediastinitis, diffuse hemorrhagic lymphadenitis, and edema. Diagnosis requires a high index of suspicion. Treatment involves supportive care in an intensive care facility and high doses of penicillin. Resistance to third-generation cephalosporins has been noted. Vaccines are currently available and have been shown to be effective against aerosolized exposure in animal studies.

Tick-borne pulmonary disease: update on diagnosis and management.

Ticks are capable of transmitting viruses, bacteria, protozoa, and rickettsiae to man. Several of these tick-borne pathogens can lead to pulmonary disease. Characteristic clinical features, such as erythema migrans in Lyme disease, or spotted rash in a spotted fever group disease, may serve as important diagnostic clues. Successful management of tick-borne diseases depends on a high index of suspicion and recognition of their clinical features. Patients at risk for tick bites may be coinfected with two or more tick-borne pathogens. A Lyme vaccine has recently become available for use in the United States. Disease prevention depends on the avoidance of tick bites. When patients present with respiratory symptoms and a history of a recent tick bite or a characteristic skin rash, a differential diagnosis of a tick-borne pulmonary disease should be considered. Early diagnosis and appropriate antibiotic therapy for these disorders lead to greatly improved outcomes.

Diaphragmatic paralysis due to Lyme disease.

Lyme disease is a tick-borne spirochaete infection which, in a proportion of patients, can lead to neuropathy. This article describes a case of diaphragmatic paralysis due to Lyme disease. A 39-yr-old male presented to the hospital because of an acute left facial palsy. Six weeks prior to admission he had developed a circular rash on his left flank during a camping holiday. He also complained of shortness of breath and arthralgia for 1 week. His chest radiograph demonstrated a raised right hemi-diaphragm. Diaphragmatic paralysis was confirmed by fluoroscopy (a positive sniff test). Serology revealed evidence of recent infection by Borrelia burgdorferi. On the basis of the patient's clinical presentation, a recent history of erythema migrans, and positive Lyme serology, a diagnosis of neuroborreliosis was made. He received oral doxycycline therapy (200 mg x day(-1)) for three weeks. Facial and diaphragmatic palsies resolved within eight weeks. On the basis of this case, a diagnosis of Lyme disease should be considered in patients from endemic regions with otherwise unexplained phrenic nerve palsy.

Mycobacterium avium-intracellulare pulmonary infection in HIV-negative patients without preexisting lung disease: diagnostic and management limitations.

STUDY OBJECTIVES: To review the experience of an outpatient pulmonary clinic with Mycobacterium avium-intracellulare (MAI) pulmonary disease in the HIV-negative population without preexisting lung disease. DESIGN: Retrospective clinical series. SETTING: University medical center. PATIENTS: The clinic charts of all patients who fulfilled the current American Thoracic Society criteria for MAI pulmonary infection and who had no preexisting lung disease or immunosuppression were reviewed. MEASUREMENTS AND RESULTS: Of 31 patients identified, 94% were female, 90% were white, and the median age at diagnosis was 63 years. The median time interval from symptom onset to diagnosis was 10 months. Bronchiectasis or small nodules without predilection for any lobe was found in 93%. Bronchoscopy or open lung biopsy for diagnosis was required in 45% because of nondiagnostic sputum cultures. At > or = 12 months, 50% failed therapy, 86% continued to be symptomatic, and 58% did not tolerate their initial multidrug regimen. CONCLUSIONS: These results emphasize the observed chronic nature of MAI pulmonary disease in this population, both before diagnosis and despite therapy. The sensitivity of sputum culture in this population is low, so an aggressive diagnostic approach, including bronchoscopy, should be considered if sputum cultures are negative. Current treatments are suboptimal because of poor drug tolerance and significant failure rates. Last, the preponderance of disease in older white women argues for a genetic or acquired immune deficiency to explain disease susceptibility.

Analyses of the NRAMP1 and IFN-gammaR1 genes in women with Mycobacterium avium-intracellulare pulmonary disease.

Mycobacterium avium-intracellulare (MAI) pulmonary disease causes substantial morbidity in a population of older, HIV-negative women without preexisting lung disease. The cause for disease susceptibility in these patients is unknown, although their relative phenotypic homogeneity suggests the existence of a common, subtle immune deficiency. An investigation was undertaken to determine if these patients have a defect in their natural resistance-associated macrophage protein (NRAMP1) or interferon gamma receptor 1 (IFN-gammaR1) genes. A point mutation in murine nramp, an autosomal recessive gene controlling resistance to intracellular organisms, correlates with overwhelming Mycobacterium bovis infection in mice. The corresponding region in human NRAMP1, two coding polymorphisms and one promoter NRAMP1 polymorphism, as well as two IFN-gammaR1 polymorphisms, were analyzed to determine if an allele was present to correlate with disease. Genomic DNA was purified from eight women with MAI pulmonary disease and four controls. Regions of interest were amplified by PCR; three sites were analyzed by restriction fragment length polymorphisms, and three were analyzed using denaturing high-performance liquid chromatography. The NRAMP1 promoter polymorphism of 18 additional random controls was analyzed by microsatellite sizing. No allelism was found in NRAMP1 corresponding to the murine mutation, or in the two coding regions. In the NRAMP1 promoter microsatellite, 3 of 8 patients were heterozygous for a dinucleotide sequence insertion, as were 10 of 22 controls. None of the patients had either of the two known IFN-gammaR1 mutations. In conclusion, in women with MAI pulmonary disease, there is no evidence for a genetic defect in NRAMP1 or IFN-gammaR1 to correlate with disease.

Pulmonary capillaritis and alveolar hemorrhage. Update on diagnosis and management.

Pulmonary vascular inflammatory disorders may involve all components of the pulmonary vasculature, including capillaries. The principal histopathologic features of pulmonary capillaritis include capillary wall necrosis with infiltration by neutrophils, interstitial erythrocytes, and/or hemosiderin, and interalveolar septal capillary occlusion by fibrin thrombi. Immune complex deposition is variably present. Patients often present clinically with diffuse alveolar hemorrhage, which is characterized by dyspnea and hemoptysis; diffuse, bilateral, alveolar infiltrates on chest radiograph; and anemia. Pulmonary capillaritis has been reported with variable frequency and severity as a manifestation of Wegener's granulomatosis, microscopic polyarteritis, systemic lupus erythematosus, Goodpasture's syndrome, idiopathic pulmonary renal syndrome, Behçet's syndrome, Henoch-Schönlein purpura, IgA nephropathy, antiphospholipid syndrome, progressive systemic sclerosis, and diphenylhydantoin use. In addition to history, physical examination, and routine laboratory studies, certain ancillary laboratory tests, such as antineutrophil cytoplasmic antibodies, antinuclear antibodies, and antiglomerular basement membrane antibodies, may help diagnose an underlying disease. Diagnosis of pulmonary capillaritis can be made by fiberoptic bronchoscopy with transbronchial biopsy, but thoracoscopic biopsy is often employed. Since many disorders can result in pulmonary capillaritis with diffuse alveolar hemorrhage, it is crucial for clinicians and pathologists to work together when attempting to identify an underlying disease. Therapy depends on the disorder that gave rise to the pulmonary capillaritis and usually includes corticosteroids and cyclophosphamide or azathioprine. Since most diseases that result in pulmonary capillaritis are treated with immunosuppression, infection must be excluded aggressively.

Thrombin receptor polymorphism in Chinese hamster.

We report the existence of a new Chinese hamster thrombin receptor allele, characterized by an in-frame insertion of three nucleotides at position 250 of the published sequence. As a consequence, an additional proline is inserted into a proline-rich region of the extracellular amino-terminal domain of the receptor. A corresponding proline at this position is also found in the rat thrombin receptor. A silent base-pair change is found in the cytoplasmic tail of the receptor gene. Single-strand conformation polymorphism and sequence analysis indicate this new receptor allele is present in several cell lines derived from different individual Chinese hamsters. Embryonic CHEF IIC9 cells and primary culture cells are homozygous for this new allele. In contrast, the CCL39 lung fibroblast cell line is heterozygous for both the new and old alleles. Both alleles are transcribed into mRNA and code for functional receptors. Given the allelic distribution and sequence alignment with thrombin receptors from other species, we propose that the new sequence represents the actual predominant allele in Chinese hamster.

Tryptase, the dominant secretory granular protein in human mast cells, is a potent mitogen for cultured dog tracheal smooth muscle cells.

Hyperplasia of airway smooth muscle cells is present in the airways of asthmatic patients and may contribute to the development of the bronchial hyperresponsiveness that occurs in these patients. Because tryptase is an abundant component of mast cell granules and has demonstrated growth-stimulatory effects in other mesenchymal cells (J. Clin. Invest. 1991; 88:493-499), the goal of our study was to determine whether tryptase is a mitogen for airway smooth muscle cells. The mitogenic effects of tryptase were tested in passages 1 through 5 of dog tracheal smooth muscle cells, either by counting smooth muscle cells or by monitoring uptake of bromodeoxyuridine (BrdU) into cellular DNA during S-phase. With respect to its efficacy, at a near maximal concentration (4 nM), tryptase increased cell numbers 2.1 +/- 0.2- or 2.8 +/- 0.6-fold above controls after 2 or 4 days, respectively, and these increases were approximately the same as those induced by platelet-derived growth factor (50 ng/ml) or 10% calf serum. With respect to potency, tryptase caused concentration-dependent increases in BrdU uptake, as detected in an enzyme-linked immunosorbent assay or by counting BrdU-labeled nuclei, with an EC50 of 2 nM. Pretreatment of tryptase with diisopropylfluorophosphate, to reduce markedly its catalytic as a activity as a proteinase, attenuated its growth-stimulated effects by 58 +/- 16%. Tryptase-induced mitogenesis was not a nonspecific effect of all serine proteinases, because thrombin, another proteinase with mitogenicity for fibroblasts, stimulated neither increases in cell counts nor BrdU uptake in our cells. We conclude that tryptase is a potent mitogen for airway smooth muscle cells in culture.