Noninvasive ventilation in intensive care unit patients.
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Critical Illness↗
Biomedical subjects
M Rocco
Publications and source records attributed to M Rocco.
Effects of ligand-mimetic peptides Arg-Gly-Asp-X (X = Phe, Trp, Ser) on alphaIIbbeta3 integrin conformation and oligomerization.
The purpose of this investigation was to determine what structural changes convert "inert" alphaIIbbeta3 integrins into "activated" high-affinity receptors for adhesive proteins. Light scattering, analytical ultracentrifugation, electron microscopy, and molecular modeling were used to probe the conformational states of the alphaIIbbeta3 integrin. Isolated from human blood platelets in octyl glucoside, the alphaIIbbeta3 complex behaved as an asymmetric 230 kDa macromolecule with a z-average translational diffusion coefficient of 2.9 F and a weight-average sedimentation coefficient of 7.7 S. Dynamic light scattering showed that ligand-mimetic peptides (RGDX, X = F, W, S) caused prompt, concentration-dependent increases in the Stokes radius (R(s)) of the alphaIIbbeta3 complex, whereas control peptides of reversed sequence (XDGR, X = F, W, S) had no significant effect. Sedimentation velocity data coupled with time-derivative analyses showed that RGDX peptides shifted the distribution of alphaIIbbeta3 sedimenting species toward smaller s values. Sedimentation equilibrium measurements indicated that a slower increase in the alphaIIbbeta3 molecular weight distribution took place in the presence of RGDX ligand-mimetics. Electron microscopy showed a split of alphaIIbbeta3's globular domain into two distinct nodules in the presence of RGDX peptides; oligomers joined through their stalk regions were seen frequently. These observations suggest that receptor occupancy by ligand-mimetic RGDX peptides is tightly coupled to relatively large changes in the structure of the alphaIIbbeta3 complex. alphaIIbbeta3 bead models were developed to describe quantitatively the ligand-induced transition from a "closed" to an "open" integrin conformation and the limited oligomerization that follows. This provides a new mechanistic framework for understanding integrin activation and the formation of signaling clusters on the surface of stimulated platelets.
Amino Acid Sequence↗
Can dialysis therapy be improved? A report from the ESRD Core Indicators Project.
We assessed the association between quality improvement interventions conducted during the End-Stage Renal Disease (ESRD) Core Indicators Project and changes in the adequacy of hemodialysis between 1993 and 1996. Improvement of hemodialysis adequacy was measured by baseline and annual urea reduction ratios (URRs) in representative samples of ESRD Network patients. Random samples of in-center hemodialysis patients aged 18 years and older who had received hemodialysis during the fourth quarters of 1993, 1994, 1995, and 1996 were used to calculate Network-specific outcomes. A mean URR was calculated for each patient using the first pretreatment and posttreatment blood urea nitrogen for October, November, and December of each study year. Both national and Network-specific interventions were used to provide feedback reports and technical assistance to treatment centers to foster improvement in hemodialysis adequacy. All Networks distributed reports on the patterns of treatment center URR levels and physician and patient educational materials to each center in the Network. Each Network selected an annual 10% sample of treatment centers in 1994 and 1995 and conducted quality improvement activities to assist the selected centers to improve dialysis adequacy. We defined Network-specific interventions by a survey of the 18 Networks conducted during 1995 to determine the characteristics of Network-specific activities used to improve adequacy of hemodialysis. The outcome of interest was the change over time in Network-specific URR value. Sustained improvement in the URR occurred within all 18 Networks between 1993 and 1996. The mean national URR increased from 62.7% in 1993 to 66. 8% in 1996. The proportion of patients with URR >/= 65% increased from 43% in 1993 to 68% in 1996. Networks reported implementing a variety of intervention strategies that included educational activities, continuous quality improvement workshops, on-site assistance, and supervision of selected treatment facilities until care improved. Network-specific interventions independently associated with an increased rate of improvement in URR included prolonged supervision of the selected facilities. We concluded that the sustained improvement in hemodialysis care that occurred after the inception of the ESRD Core Indicators Project was associated with specific ESRD Network interventions.
Adolescent↗
A comparison of noninvasive positive-pressure ventilation and conventional mechanical ventilation in patients with acute respiratory failure.
BACKGROUND AND METHODS: The role of noninvasive positive-pressure ventilation delivered through a face mask in patients with acute respiratory failure is uncertain. We conducted a prospective, randomized trial of noninvasive positive-pressure ventilation as compared with endotracheal intubation with conventional mechanical ventilation in 64 patients with hypoxemic acute respiratory failure who required mechanical ventilation. RESULTS: Within the first hour of ventilation, 20 of 32 patients (62 percent) in the noninvasive-ventilation group and 15 of 32 (47 percent) in the conventional-ventilation group had an improved ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2:FiO2) (P=0.21). Ten patients in the noninvasive-ventilation group subsequently required endotracheal intubation. Seventeen patients in the conventional-ventilation group (53 percent) and 23 in the noninvasive-ventilation group (72 percent) survived their stay in the intensive care unit (odds ratio, 0.4; 95 percent confidence interval, 0.1 to 1.4; P=0.19); 16 patients in the conventional-ventilation group and 22 patients in the noninvasive-ventilation group were discharged from the hospital. More patients in the conventional-ventilation group had serious complications (66 percent vs. 38 percent, P=0.02) and had pneumonia or sinusitis related to the endotracheal tube (31 percent vs. 3 percent, P=0.003). Among the survivors, patients in the noninvasive-ventilation group had shorter periods of ventilation (P=0.006) and shorter stays in the intensive care unit (P=0.002). CONCLUSIONS: In patients with acute respiratory failure, noninvasive ventilation was as effective as conventional ventilation in improving gas exchange and was associated with fewer serious complications and shorter stays in the intensive care unit.
Acute Disease↗
Idiopathic left ventricular aneurysm: an unusual substrate of ventricular fibrillation and ventricular tachycardia.
Idiopathic left ventricular aneurysm (LVA) is a very rare clinical condition. This article describes a patient with idiopathic LVA associated with episodes of ventricular tachycardia and ventricular fibrillation. Clinical and instrumental examinations did not reveal the pathogenesis of the aneurysm. The malignant clinical course suggests that an aggressive antiarrhythmic treatment, including ICD implantation, may be warranted.
Anti-Arrhythmia Agents↗
Functional and ultrastructural evidence of myocardial stunning after acute carbon monoxide poisoning.
OBJECTIVE: To study human myocardial ultrastructural changes after carbon monoxide (CO) poisoning inducing reversible cardiac failure. DESIGN CASE REPORT: clinical, functional and morphologic findings. SETTINGS: Public university-affiliated hospital and electron microscopy laboratory. PATIENT: A 25-yr-old woman with functional evidence of cardiac failure after acute CO poisoning. INTERVENTIONS: Hyperbaric and intensive care treatment over 10 days. Scintigraphic and cardiac angiography with endomyocardial biopsy. MEASUREMENTS AND MAIN RESULTS: Scintigraphy with 99mTc hexakis 2-methoxy-2-isobutyl isonitrile (sestaMIBI) showed an uptake defect in the left anterior descending artery territory. The cardiac angiography demonstrated a slight hypokinesis of the superior two thirds of the anterior wall and of the septal region with completely normal coronary angiograms. Electron microscopy of left ventricular biopsies showed slight ultrastructural changes in the myocytes. In addition, large glycogen deposits were mostly associated with swollen mitochondria. The patient was discharged in good clinical condition on day 10. CONCLUSIONS: Presence of glycogen deposits associated with abnormal mitochondria may be signs of the incapability of myocardial cells in utilizing energy substrata. In the presence of normal myocardial perfusion, our findings are consistent with the presence of a stunned myocardium-like syndrome. Early recognition and treatment of this clinical syndrome allow the prevention of myocardial infarction.
Adult↗
Proliferating cell nuclear antigen (PCNA), DNA synthesis and mitosis in myocytes following cardiac transplantation in man.
Cardiac transplantation is characterized by rejection, myocyte loss, interstitial and replacement fibrosis, and loading abnormalities. These modifications contribute to enhance mural and muscle cell stress, activating reactive growth processes in myocytes and interstitial cells. However, it is unknown whether cell cycle related gene product, such as PCNA, and DNA synthesis are stimulated under these conditions. Therefore, 62 endomyocardial biopsies obtained from 17 patients who underwent cardiac transplantation were examined for the immunocytochemical detection of PCNA protein in myocyte and non-myocyte nuclei. In addition, tissue samples were labeled in vitro with bromodeoxyuridine (BrdU) to document ongoing DNA synthesis. The presence of mitotic images in myocytes and non myocytes were also examined. Biopsies were collected from 1-768 days after surgery. Histologic examination of tissue sections documented that PCNA labeling involved nearly 30% of myocyte nuclei in all patients. Similar percentages of PCNA labeling were detected in interstitial cells, lymphocytes and mononuclear infiltrates. DNA synthesis in myocytes and connective tissue cells was observed in nine and 14 subjects, respectively. BrdU positive lymphocytes and mononuclear infiltrates in 13 cases. Three mitotic figures in myocyte nuclei were identified. PCNA, BrdU labeling and mitosis were not detected in eight myocardial samples obtained from control hearts. These results suggest that the evolution of the transplanted heart involves the expression of a gene which is implicated in DNA replication. The presence of ongoing DNA synthesis and mitosis support the notion that proliferation of myocytes and non muscle cells may be a component of ventricular remodeling after cardiac transplantation.
Bromodeoxyuridine↗
Respiratory system mechanics in the early phase of acute respiratory failure due to severe kyphoscoliosis.
OBJECTIVE: To evaluate respiratory mechanics in the early phase of decompensation in a group of seven patients with severe kyphoscoliosis (KS) (Cobb angle > 90 degrees) requiring mechanical ventilatory support. DESIGN: Prospective clinical study with a control group. SETTING: General intensive care unit at University of Rome "La Sapienza". PATIENTS: Seven consecutive patients affected by severe KS in the early phase of acute decompensation and a control group of six ASA (American Society of Anesthesiology) 1 subjects who were mechanically ventilated during minor surgery. MEASUREMENTS AND RESULTS: Respiratory mechanics were evaluated during constant flow-controlled mechanical ventilation at zero end-expiratory pressure with the end-inspiratory and end-expiratory occlusion technique. In five patients who showed increased ohmic resistance (RRSmin), we evaluated the possibility of reversing this increase with a charge dose of 6 mg/kg doxophylline i.v. In four KS patients, in whom a reliable esophageal pressure was confirmed by a positive occlusion test, we separated respiratory system data into lung and chest wall component. All KS patients showed reduced values of respiratory compliance (CRS) and increased respiratory resistance (RRS). The average basal values of CRS were 36 +/- 10 vs 58 +/- 8.5 cmH2O in control patients; RRSmax was 20 +/- 3.1 vs. 4.5 +/- 1.2 cmH2O/1 per s; RRSmin 6.2 +/- 1.2 vs. 2 +/- 0.5 cmH2O/1 per s: delta RRS 14 +/- 2.6 cmH2O vs 2.4 +/- 0.7 cmH2O/1 per s. All KS patients showed low values of intrinsic positive end-expiratory pressure (PEEPi) (1.8 +/- 1.5 cmH2O). Separation of lung and chest-wall mechanics, performed only in four patients, showed a reduction in both lung (66.7 +/- 7.2 ml/cmH2O) and chest wall values (84 +/- 8.2 ml/cmH2O), while both RmaxL and RmaxCW were increased (16.6 +/- 2 and 2.8 +/- 0.4 cmH2O/1 per s, respectively). Infusion of doxophylline did not significantly change respiratory mechanics when evaluated 15, 30, and 45 min after the infusion. CONCLUSIONS: During acute decompensation, both lung and chest-wall compliance are severely reduced in KS patients: conversely, and, contrary to that in patients with chronic obstructive pulmonary disease, increases in airway resistance and PEEPi seem to play only a secondary role.
Airway Resistance↗
Hyperbaric oxygen in chronic cluster headaches: influence on serotonergic pathways.
A controlled study was done with the aim of assessing the efficacy of hyperbaric oxygen (HBO2) in cluster headache and of studying the possible influence of this therapeutic approach on serotonergic pathways. Fourteen patients, aged between 26 and 56 yr, suffering from the chronic form of cluster headache were treated with HBO2 (n = 10) or environmental air (placebo) ( n = 4) during the 15 sessions of exposure (lasting 30 min each) in the hyperbaric chamber. The influence of this procedure on serotonergic pathways of pain was monitored by means of study of serotonin binding to mononuclear cells before and after the treatment for both subgroups. All of the treated 14 chronic cluster headache patients completed the study. In the subgroup treated with the placebo, no particular modifications on the number of attacks and of analgesic consumption as well as no change in the specific binding curve of serotonin to mononuclear cells were observed, whereas in the subgroup treated with HBO2 the clinical effectiveness and the appearance of plateau in the binding curves indicated that the oxygen therapy could act through serotonergic pathways.
Adult↗
Causes of late failure after heart transplantation: a ten-year survey.
BACKGROUND: Little is known about the causes of death of heart transplant recipients who survive long-term. METHODS: The pathologic and clinical records of 97 patients who underwent heart transplantation in Italy from 1985 to 1995 and died (85 of 97) or underwent retransplantation (12 of 97) at least 2 years after transplantation were surveyed. Graft failures were classified as late (occurring between 2 and 5 years after transplantation) and belated (more than 5 years). RESULTS: Graft vasculopathy was the single most common cause of death (40.0%) and the only cause of late retransplantation. Tumors ranked second (23.5% of deaths), but the expected non-Hodgkin's lymphomas and Kaposi's sarcoma were accompanied by a high number of lung cancers (especially metastasizing adenocarcinomas). They were followed by the emergence or recurrence of pretransplantation diseases (9.4%), fatal infections (exclusively bacterial) (4.7%), the development of transmissible diseases (viral hepatitis and acquired immunodeficiency syndrome, 4.7%), and late acute rejection (2.3%). The distribution of failures differed in the late and belated periods: death and organ loss proportions for graft vasculopathy, respectively, fell and rose from the late to the belated period; some types of malignancy and fatal acute rejection were never observed in the belated period, whereas the emergence of pretransplantation diseases prevailed in the belated period. Graft vasculopathy was more frequent and tumors were less frequent among patients undergoing transplantation for ischemic heart disease. CONCLUSIONS: The reasons why heart transplant recipients die or undergo retransplantation, respectively, in the late and belated periods slightly differ from one another and are widely different than in short-term survivors.
Bacterial Infections↗
Effect of hyperbaric oxygen on the immunoreactivity to substance P in the nasal mucosa of cluster headache patients.
Exposure to hyperbaric oxygen has been shown to be effective in cluster headache, but the mechanism of the action is still not clear. Primary nociceptive neurons, containing neuropeptides such as substance P and particularly those innervating the nasal mucosa, could be involved in the pathogenesis of cluster headache. The present study evaluated the effect of an exposure to hyperbaric oxygen on the content of substance P in the nasal mucosa of patients affected by cluster headache. The results were compared with those observed in another group of cluster headache patients who underwent a placebo procedure. The samples of nasal mucosa were analyzed by immunocytochemical methods. A qualitative analysis of the slides was carried out by an operator under "blinded conditions". A marked decrease in the content of immunoreactivity for substance P was found in the patients exposed to hyperbaric oxygen. The decrease was statistically significant when compared with the findings of the placebo procedure. The results of the present study indicate that an influence on the content of peripheral neuropeptides could be involved in the mechanism of action of the beneficial effect of hyperbaric oxygen in cluster headache.
Adult↗
Computer-assisted morphometric analysis of the heart.
OBJECTIVE: To assess the applicability of the image analyzer for morphometric study of cardiomyopathies. STUDY DESIGN: A computer-assisted methodology for the morphometric study of ischemic cardiomyopathy, dilated cardiomyopathy and right ventricular dysplasia. RESULTS: In each heart, 200 nuclear lengths and myocyte diameters, 160 fields for nuclear density, 420 fields for interstitial fibrosis and 350 fields for replacement fibrosis were evaluated. In ischemic cardiomyopathy, the multiple foci of replacement fibrosis of the myocardium, in addition to interstitial fibrosis, appear to be the major cause of ventricular remodelling. In dilated cardiomyopathy the major pathologic processes are myocyte cell death and segmental, replacement and interstitial fibrosis. In right ventricular dysplasia the heart develops congestive failure due to a conspicuous increase in the volume of the right ventricle without an appreciable loss of the number of myocytes. CONCLUSION: The traditional morphometric methods based on test grids for the study of pathologic hearts can be enhanced using an image analyzer. In this way one can study a large area of the myocardium and collect a very large number of data. This may be the method of choice for analyses of pathologic human hearts.
Cardiomyopathies↗
[Solid papillary tumor of the pancreas. A clinical case].
The solid papillary tumor of the pancreas is a relative rare neoplasm that often is unknown because of its diagnostic difficulties. It is frequent in young women. It has no typical clinical signs, sometimes produces abdominal mass, sometimes is found casually during investigations for other diseases. Instead the prognosis of this tumor is more typical: long-term survival is good. The natural history of the solid papillary is the same as neoplasm with a low malignancy potential. For this reason, it's important to make up a differential diagnosis between it and the other pancreatic tumors. Unlike the other malignancies, surgical conservative therapy is enough without making great demolitions of the pancreas. Lumpectomy gives a complete cure, decreasing surgical risk and dangerous functional complications. In the present paper, a case of solid papillary tumour of the pancreas is reported. It was diagnosed in a young woman and treated with simple lumpectomy. She is alive and disease free.
Adult↗
Induction of kinetochore-containing micronuclei by exogenous O6-methylguanine requires conversion of the methylated base to a nucleotide.
It has been reported that exogenous alkylated purines, such as O6-methylguanine (O6meG), induce aneuploidy in mammalian cells. It is shown here that the aneugenic effect of O6meG, evidenced by its ability to induce micronuclei in rodent cells, is dependent on its conversion to O6-methyl-guanosine-5'-monophosphate (O6me-5'-GMP) by hypoxanthine-guanine phosphoribosyl transferase (HPRT). This conclusion, in contrast with previous in vitro data showing that O6meG does not seem to be a substrate for HPRT, was based on the following observations: 1) O6meG did not induce micronuclei in HPRT-deficient Chinese hamster cells, but did induce micronuclei in HPRT-proficient cells, and in mouse cells partially or totally deficient in adenine phosphoribosyl transferase; 2) O6meG was not metabolized in HPRT-deficient cells, while in wild-type cells a number of metabolites were detected by high performance liquid chromatography (HPLC) analysis of cold acid extracts, one of them coeluting with O6me-5'-GMP used as a marker; 3) when de novo synthesis of purine nucleotides was inhibited by aminopterin, O6meG sustained the growth of HPRT-proficient, but not of HPRT-deficient, cells; and 4) when HPRT-deficient cells were treated with liposomes charged with O6me-5'-GMP, induction of micronuclei was shown. The finding that methylated guanine exerts its aneugenic action through methylated nucleotide(s) provides an important, though indirect, support to the hypothesis that alkylating agents may induce aneuploidy via nucleotide pool alkylation.
Adenine↗
Paralysis has no effect on chest wall and respiratory system mechanics of mechanically ventilated, sedated patients.
OBJECTIVE: To evaluate the separate effects of sedation and paralysis on chest wall and respiratory system mechanics of mechanically ventilated, critically ill patients. SETTING: ICU of the University "La Sapienza" Hospital, Rome. PATIENTS AND PARTICIPANTS: 13 critically ill patients were enrolled in this study. All were affected by disease involving both lungs and chest wall mechanics (ARDS in 4 patients, closed chest trauma without flail chest in 4 patients, cardiogenic pulmonary oedema with fluidic overload in 5 patients). MEASUREMENTS AND RESULTS: Respiratory system and chest wall mechanics were evaluated during constant flow controlled mechanical ventilation in basal conditions (i.e. with the patients under apnoic sedation) and after paralysis with pancuronium bromide. In details, we simultaneously recorded airflow, tracheal pressure, esophageal pressure and tidal volume; with the end-inspiratory and end-expiratory airway occlusion technique we could evaluate respiratory system and chest wall elastance and resistances. Lung mechanics was evaluated by subtracting chest wall from respiratory system data. All data obtained in basal conditions (with the patients sedated with thiopental or propofol) and after muscle paralysis were compared using the Student's t test for paired data. The administration of pancuronium bromide to sedated patients induced a complete muscle paralysis without producing significant modification both to the viscoelastic and to the resistive parameters of chest wall and respiratory system. CONCLUSIONS: This study demonstrates the lack of additive effects of muscle paralysis in mechanically ventilated, sedated patients. Also in view of the possible side effects of muscle paralysis, our results question the usefulness of generalized administration of neuromuscular blocking drugs in mechanically ventilated patients.
Adult↗
The cellular basis of dilated cardiomyopathy in humans.
The present investigation was designed to evaluate whether end-stage cardiac failure in patients affected by dilated cardiomyopathy (DC) was dependent upon extensive myocyte cell death with reduction in muscle mass or was the consequence of collagen accumulation in the myocardium independently from myocyte cell loss. In addition, the mechanisms of ventricular dilation were analysed in order to determine whether the changes in cardiac anatomy were important variables in the development of intractable congestive heart failure. DC is characterized by chamber dilation, myocardial scarring and myocyte hypertrophy in the absence of significant coronary atherosclerosis. However, the relative contribution of each of these factors to the remodeling of the ventricle is currently unknown. Moreover, no information is available concerning the potential etiology of collagen deposition in the myocardium and the changes in number and size of ventricular myocytes with this disease. Morphometric methodologies were applied to the analysis of 10 DC hearts obtained from patients undergoing cardiac transplantation. An identical number of control hearts was collected from individuals who died from causes other than cardiovascular diseases. DC produced a 2.2-fold and 4.2-fold increase in left ventricular weight and chamber volume resulting in a 48% reduction in mass-to-volume ratio. In the right ventricle, tissue weight and chamber size were both nearly doubled. Left ventricular dilation was the result of a 59% lengthening of myocytes and a 20% increase in the transverse circumference due to slippage of myocytes within the wall. Myocardial scarring represented by segmental, replacement and interstitial fibrosis occupied approximately 20% of each ventricle, and was indicative of extensive myocyte cell loss. However, myocyte number was not reduced and average cell volume increased 2-fold in both ventricles. In conclusion, reactive growth processes in myocytes and architectural rearrangement of the muscle compartment of the myocardium appear to be the major determinants of ventricular remodeling and the occurrence of cardiac failure in DC.
Autopsy↗
[Assessment of lipid peroxidation in hyperbaric oxygen therapy: protective role of N-acetylcysteine].
OBJECTIVE: To verify and quantify lipidic peroxidation by means of tiobarbituric-acid reactive substance (TBARS) dosage in patients treated daily with HBO. To verify if a potentiated glutathione enzymatic system, with N-acetylcisteine (NAC) treatment, may determine higher HBO tolerance and reduced lipidic peroxidation. DESIGN: Randomised study on patients treated with 20 HBO 2.2 ATA (90' oxygen) sessions. SETTING: Hyperbaric Medical Centre. PATIENTS: Seventeen patients divided, at random, into two groups; group A: 10 patients treated with only HBO; group B: 7 patients treated with NAC antioxidant therapy (Fluimucil, Zambon Group, Italy) 1800 mg/day in addition to HBO. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: TBARS on blood sample at T0 (basal) T1 (at the end of the 1st HBO session) T2 (at the beginning of the 20th HBO session) T3 (at the end of the 20th). The group A TBARS analysis at the different study time has shown significant data (p < 0.01) as the difference between TBARS values of the two groups at T2 (p < 0.01). CONCLUSIONS: HBO induces a lipidic peroxidation even if the therapeutical protocol cannot determine lung or cerebral oxygen toxicity symptoms. The NAC administration, during HBO treatment, determines a protection against the HBO radicalic stress.
Acetylcysteine↗
The efficiency of cysteine-mediated intracellular retention determines the differential fate of secretory IgA and IgM in B and plasma cells.
Previous studies on IgM secretion demonstrated a role for the mu chain C-terminal cysteine (Cys575) in preventing the transport of unpolymerized subunits along the secretory pathway. The sequence homology between the C-terminal tailpieces of mu and alpha heavy chains prompted us to investigate the role of cysteine-mediated, retention in the control of IgA secretion during B cell development. Similar to IgM, IgA are not secreted by B lymphocytes: the retention mechanism can be reversed by the reducing agent 2-mercaptoethanol, suggesting that disulfide interchange reactions are involved in the quality control of both IgM and IgA. Yet, alpha 2L2 subunits, but not mu2L2, are secreted constitutively by plasma cells. We demonstrate that the differential retention of IgM and IgA subunits by myeloma transfectants is mainly due to the presence of an acidic residue upstream the alpha chain C-terminal cysteine. The regulation of polymeric Ig secretion during B cell development provides an example of how thiol-mediated quality control can be modulated according to the aminoacidic context surrounding the critical cysteine and to the cell type.
Amino Acid Sequence↗