Surgical management of Mycobacterium avium complex disease

Between July 1991 and October 1996, eight patients with Mycobacterium avium complex (MAC) underwent pulmonary resection in our department. There was equal distribution of men women. The length of the preoperative period averaged 8.1 months (range: 1 to 30 months). Surgical resection was complete, consisting of lobectomy in 4 patients, lobectomy with partial resection in 2, segmentectomy in 1, and segmentectomy with partial resection in 1. There were no major complications postoperatively. No patients had positive sputum culture with MAC just after operation; however, one patient had positive sputum culture 6 months after operation. Our results show the good outcome of resectional surgery for MAC in properly selected patients, who should be operated as early as possible.

[Significance of rectal contractions during multichannel urodynamic study]

BACKGROUND

The influence of rectal contractions on urination was examined using multichannel urodynamic study.

METHODS

We reviewed a total of 246 consecutive urodynamic studies. Each study consisted of a uroflow measurement and multi-channel urodynamic study, evaluating total vesical pressure, abdominal (rectal) pressure, subtracted detrusor pressure and perianal electromyography. Rectal contractions were defined as periodic fluctuations over 5 cmH2O in abdominal pressure detected by a rectal balloon catheter. No relationship of these contractions with cough and breathing was observed.

RESULTS

Of the 246 patients, 17 (6.9%) had a positive study for rectal contractions. The patients, who had positive rectal contractions, averaged 70-year-old were older than negative subjects averaged 62-year-old. In multichannel urodynamics, the flow rate was significantly decreased, and electromyographic activity was increased at the moment of each rectal contractions.

CONCLUSIONS

The rectal contractions are not artifactual and may be regarded as one of causes responsible for urinary difficulty in the elderly.

Evaluation of magnetic resonance angiography on portosystemic collaterals in cirrhotic patients

OBJECTIVE

We examined the usefulness of imaging portosystemic collaterals accompanying liver cirrhosis by magnetic resonance angiography (MRA), which facilitates imaging of the vascular system without contrast medium.

METHODS

MRA was performed in 30 patients with liver cirrhosis. Of the 30 patients, percutaneous transhepatic portography (PTP) was performed in 10 patients, and conventional arterial portography (CAP) was performed in 20 patients. The three-dimensional (3D) phase contrast method was used for MRA. Study 1: The ability to image portosystemic collaterals was compared between PTP or CAP and MRA. Study 2: The usefulness of MRA for evaluating the effect of treatment on gastric and esophageal varices was examined.

RESULTS

Study 1: In comparing PTP and MRA (n = 10), the left gastric vein (n = 10), splenorenal (gastrorenal) shunt (n = 5), and paraumbilical vein (n = 2) were imaged similarly. However, MRA did not reveal any esophageal varices (n = 10). In comparing CAP and MRA (n = 20), the left gastric vein (n = 17), splenorenal (gastrorenal) shunt (n = 10), and paraumbilical vein (n = 4) were imaged similarly. Whereas CAP revealed esophageal varices (n = 4) in four patients, MRA revealed esophageal varices in only one patient. Study 2: When the effect of treatment for varices was evaluated, MRA 3 wk after embolization therapy for gastric varices (n = 4) confirmed the disappearance of gastrorenal shunt. However, it was impossible to evaluate esophageal varices by MRA.

CONCLUSIONS

It was possible to image portosystemic collaterals accompanying liver cirrhosis by MRA. MRA was useful as a routine examination. Furthermore, it was useful for evaluating the effect of embolization therapy on gastric varices.

Repeated elicitation of contact hypersensitivity induces a shift in cutaneous cytokine milieu from a T helper cell type 1 to a T helper cell type 2 profile

We previously demonstrated that repeated application of 2,4,6-trinitro-1-chlorobenzene resulted in a site-restricted shift in the time course of Ag-specific hypersensitivity responses from a typical delayed-type to an early-type response. Here we demonstrated that the cutaneous microenvironment at the time of Ag presentation to T cells in the elicitation, but not the induction, phase of contact hypersensitivity is responsible for the shift. To investigate the differences in the cutaneous cytokine milieu between the acute and chronic phases of contact hypersensitivity, sequential cytokine dynamics after 2,4,6-trinitro-1-chlorobenzene application were assessed in the acute vs chronic lesions. In the acute lesions, increased mRNA levels for IFN-gamma and IL-2 were rapidly detected at 1 h and remained elevated at 12 h, while mRNA expression for IL-4 and IL-10 was minimally up-regulated between approximately 12 and 24 h. In chronic lesions, high levels of constitutive expression of IL-4 mRNA were observed and IL-10 mRNA was dramatically up-regulated at 1 approximately 3 h in an Ag-specific fashion, whereas the expression of Th1-type cytokines was markedly reduced. Increased mRNA levels for Th2-type cytokines in the chronic lesions was also reflected at the protein level. These results indicate that repeated elicitation with Ag alters the balance of cytokines released locally, with a shift toward Th2-dominated responses, which would represent the natural evolution processes directed toward reducing a more deleterious Th1 response.

Repeated elicitation of contact hypersensitivity induces a shift in cutaneous cytokine milieu from a T helper cell type 1 to a T helper cell type 2 profile

We previously demonstrated that repeated application of 2,4,6-trinitro-1-chlorobenzene resulted in a site-restricted shift in the time course of Ag-specific hypersensitivity responses from a typical delayed-type to an early-type response. Here we demonstrated that the cutaneous microenvironment at the time of Ag presentation to T cells in the elicitation, but not the induction, phase of contact hypersensitivity is responsible for the shift. To investigate the differences in the cutaneous cytokine milieu between the acute and chronic phases of contact hypersensitivity, sequential cytokine dynamics after 2,4,6-trinitro-1-chlorobenzene application were assessed in the acute vs chronic lesions. In the acute lesions, increased mRNA levels for IFN-gamma and IL-2 were rapidly detected at 1 h and remained elevated at 12 h, while mRNA expression for IL-4 and IL-10 was minimally up-regulated between approximately 12 and 24 h. In chronic lesions, high levels of constitutive expression of IL-4 mRNA were observed and IL-10 mRNA was dramatically up-regulated at 1 approximately 3 h in an Ag-specific fashion, whereas the expression of Th1-type cytokines was markedly reduced. Increased mRNA levels for Th2-type cytokines in the chronic lesions was also reflected at the protein level. These results indicate that repeated elicitation with Ag alters the balance of cytokines released locally, with a shift toward Th2-dominated responses, which would represent the natural evolution processes directed toward reducing a more deleterious Th1 response.

Requirements of DFR1/Heartless, a mesoderm-specific Drosophila FGF-receptor, for the formation of heart, visceral and somatic muscles, and ensheathing of longitudinal axon tracts in CNS

DFR1 encodes a mesoderm-specific fibroblast growth factor receptor in Drosophila. Here, we identified and characterized a protein-null mutant of DFR1 and examined DFR1 expression in embryos using anti-DFR1 antibody. Mutant phenotypes were completely rescued by a genomic fragment from the DFR1 locus. After invagination, mesodermal cells expressing DFR1 undergo proliferation and spread out dorsally to form a monolayer beneath the ectoderm. In mutant embryos, however, the mesoderm is not capable of extending to the normal dorsal limit and consequently mesodermal cells fail to receive ectodermal signals and thus rendered incapable of differentiating into primordia for the heart, visceral and somatic muscles. DFR1 is also required for normal development of the central nervous system. The absence of DFR1 resulted in the failure of longitudinal glia to enwrap longitudinal axon tracts. DFR1 mutant phenotypes were partially mimicked by the targeted expression of activated Yan, thus demonstrating the MAP kinase pathway to be involved in differentiation of mesoderm.

Basal interhemispheric supra- and/or infrachiasmal approaches via superomedial orbitotomy for hypothalamic lesions: preservation of hypothalamo-pituitary functions in combination treatment with radiosurgery

Although several approaches to the hypothalamus have been used, none is able to give full views of the hypothalamus. The risk of permanent morbidity for hypothalamo-pituitary functions is still high, especially in patients with craniopharyngioma. Basal interhemispheric supra-chiasmal or infra-chiasmal approaches via superomedial orbitotomy were developed for better visualization of the hypothalamus. Operative techniques and results, including combination treatment with radiosurgery, are reported. Twelve patients with tumors compressing the hypothalamus upward or extending into the III ventricle, or both, were operated on: 3 tumors were removed totally, 6 tumors subtotally and 3 tumors partially. Six patients received radiosurgery for residual tumor. Four patients with hypopituitarism preoperatively required oral corticosteroids and thyroid hormones postoperatively. The basal interhemispheric approach via superomedial orbitotomy is useful for better visualization of the hypothalamus and preservation of hypothalamo-pituitary functions.

Renal effects of a nitric oxide donor, NOC 7, in anesthetized rabbits

Intrarenal arterial infusion of angiotensin II (4 ng/kg per min) reduced glomerular filtration rate and urinary Na+ excretion without affecting fractional Na+ excretion. Infusion of norepinephrine (30 ng/kg per min) reduced both urinary Na+ excretion and fractional Na+ excretion with a slight hypofiltration. The angiotensin II- and the norepinephrine-induced renal responses were suppressed during simultaneous infusion of a spontaneous nitric oxide donor 1-hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl 1-triazene (NOC 7, 30 ng/kg per min) which itself had little influence on the renal parameters. The results suggest that in the rabbit kidney in vivo NOC 7 can interfere with the angiotensin II-induced hypofiltration and norepinephrine-evoked tubular reabsorption and thereby suppresses their antinatriuretic actions.

An unusual variant of ependymoma with extensive tumor cell vacuolization

We report a case of ependymoma with unusual vacuolar features arising in the left occipital lobe of a 2-year-old child. The tumor was composed of cells with single or multiple cytoplasmic vacuoles and clear cells. Some cells showed a signet ring-like configuration. Clear cells were compactly arranged and showed an oligodendro-glioma-like appearance. In addition, there were cellular ependymoma-like areas including perivascular pseudorosettes. On immunohistochemistry, glial fibrillary acidic protein and vimentin were mainly detected in cytoplasmic processes, and epithelial membrane antigen (EMA) staining showed granular and small vesicular reactivity. Ultrastructural investigation demonstrated intercellular microrosettes with or without cilia and long zonula adherens-type junctions that are typical of ependymoma. Furthermore, many intracytoplasmic lumina (ICL) were observed. Some ICL had microvilli and some did not. The latter varied in size, and may have fused with each other to develop giant ICL which could correspond to the signet ring-like configuration. Small ICL without microvilli had an appearance similar to that of distended endoplasmic reticula. Serial semithin and ultrathin sections revealed that EMA-positive structures were consistent with ICL containing microvilli and intercellular microrosettes. To determine the presence of unusual vacuolated ependymoma, electron microscopical examination was required. However, light microscopy was useful for detecting EMA-positive microvesicular and granular structures.

Three cases of renal angiomyolipoma

We report three non-typical cases of renal angiomyolipoma including clinical features, imaging examinations (with ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI) and angiography) and histological findings. Microaneurysms observed by angiography were common to the three cases and were considered to be an important finding in the diagnosis of renal angiomyolipoma. Moreover, the short tau inversion recovery (STIR) method of MRI, which suppresses photon signals of fat, was considered to be useful for the diagnosis. Case 1 was accompanied by spontaneous rupture, Case 2 was difficult to diagnose because of little fat tissue and Case 3 revealed a very small tumor.

Effects of intrathecal nonnarcotic analgesics on chronic tactile allodynia in rats: alpha 2-agonists versus somatostatin analog

The effects of the intrathecal alpha 2-agonists tizanidine and clonidine and the somatostatin analog octreotide on an experimental rat model of tactile allodynia were investigated to determine the therapeutic potential for treating chronic neuropathic pain. Allodynia was induced by ligating the rat sciatic nerve. The mechanical threshold for paw withdrawal was assessed by applying von Frey hairs to quantify analgesic actions. Mean 50% paw withdrawal thresholds were converted to the percentage of maximum possible effect (%MPE) where %MPE = (postdrug threshold-predrug threshold) divided by (15 g-predrug threshold) x 100. Dose-response curves were plotted for suppression of paw withdrawal 30 minutes after intrathecal injection of various doses of tizanidine, clonidine, and octreotide. Thresholds on the non-lesioned side were greater than 15 g. The lesioned side had baseline thresholds of less than 4.5 g. Dose-response curves were established for the antiallodynia effects of each drug. Tizanidine and clonidine at a 25-micrograms dose increased the threshold to greater than 97% of the MPE, but caused transient hindpaw weakness or sedation. No side effect was observed at a 10-micrograms dose, at which the threshold was 88-96% of MPE. Intrathecal octreotide modestly increased the threshold to only 49-67% of MPE, showing a lesser analgesic effect, although no side effect was observed at a 4-micrograms dose. The antiallodynic effects of intrathecal tizanidine and clonidine were more potent than that of octreotide.

A theoretical integration of Cambrian explosion and post-Permian quiescence

Trophic dynamics is internally causative. Each trophic level is causative in initiating changes in trophic flow either as a supplier towards the upper level or as a consumer towards the lower. Resource presentation followed by its subsequent exploitation makes suppliers causative, while resource exploitation followed by its subsequent presentation makes consumers causative. Trophic dynamics of supplier domination gradually alternates with that of consumer domination while being punctuated by occasional mass extinctions due to depletion of the resources towards the lowest trophic level. The Cambrian explosion could be associated with trophic dynamics of supplier domination, whereas the post-Permian quiescence with that of consumer influencing supplier domination.

Interplay of causation between suppliers and consumers in evolutionary trophic dynamics

Natural selection, conceived as the process of small causes making small effects on the level of molecular evolutionary dynamics of a population, can yield global effects on the level of evolutionary trophic dynamics of populations, including those of mass extinctions. Occurrence of mass extinctions is due to the interplay of causation between suppliers and consumers in trophic dynamics. If the case of supplier causation is available such that resource exploitation by consumers on the upper trophic level follows in time resource presentation by suppliers on the lower, instead of resource exploitation followed by resource presentation, mass extinctions could be a norm of the evolutionary trophic dynamics.

Ubiquity of omnivores in natural ecosystems

Evolutionary ubiquity of omnivores in natural food webs derives from the measurement dynamics of intra and inter trophic levels. It is recognized that inter-level communication for the maintenance of energy flow continuity takes longer than intra-level communication does. Although the collapse of food webs due to depletion of the lower levels is inevitable according to the measurement dynamics; participation of omnivores could extend the evolutionary durability of the food webs.

Effects of tri-, di- and monobutyltin on synaptic parameters of the cholinergic system in the cerebral cortex of mice

Triorganotin compounds like tributyltin have been reported to be biodegraded to diorganotin, monoorganotin and then inorganic tin in animals after they have been ingested. Effects of tributyltin, dibutyltin and monobutyltin on various cholinergic parameters that are involved in synaptic transmission in the mouse cerebral cortex were investigated in vitro. Tributyltin and dibutyltin, but not monobutyltin, inhibited the activity of choline acetyltransferase, both the high-affinity and low-affinity uptakes of choline into synaptosomes, and the binding of [3H]quinuclidinyl benzilate to muscarinic acetylcholine receptors. Tributyltin and dibutyltin, but not monobutyltin, had a slightly suppressive effect on the K(+)-induced release and synthesis of acetylcholine in slices of the cortex. All three butyltins at concentrations from 10(-6) to 10(-4) M had no effect on the activity of acetylcholinesterase. The extent of the inhibitory effects on the cholinergic parameters, apart from the activity of acetylcholinesterase, was slightly greater in the case of tributyltin than dibutyltin, in particularly at the highest concentration (10(-4) M) tested. Therefore, it is concluded that tributyltin metabolites inhibit various parameters of cholinergic activity with a potency ranking of tributyltin > dibutyltin > monobutyltin.

Intercostal hemangioma

Chest wall tumors are uncommon and there have been only a few reports of intercostal hemangioma during the past 20 years. We treated a 33-year-old man who presented with intercostal hemangioma. We resected tumor and surrounding muscles beyond the limits of the lesion without removing any bone or lung tissue. The patient is free of any recurrence 3 years after surgery.

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

To clarify the mechanism of Ca2+ involvement in the DNA transfer through cell membrane, we studied the effects of Ca2+-chelator, Ca2+-ionophore, and Ca2+-channel blocker on the protoplast transfection of Lactobacillus casei ATCC 27092 by PL-1 phage DNA in the presence of Ca2+. Ca2+-chelators, citrate, EDTA, and dipicolinic acid, inhibited the transfection probably by compensating the effect of Ca2+. Ca2+-ionophores, A23187 and N,N,N', N'-tetracyclohexyl-3-oxapentanediamide, which were expected to accelerate transfection by introducing Ca2+ into cells, inhibited the transfection. This fact indicated the absence of correlation between the entry of Ca2+ and the transport of DNA into protoplasts. Verapamil, which blocks voltage-dependent Ca2+-channel besides beta-adrenergic receptor, inhibited the transfection with little effect on the survival of the protoplasts. Both flunarizine and vinpocetine, voltage-dependent Ca2+-channel blockers, did not show the selective toxicity. D-alpha-Aminoadipic acid, a glutamate receptor-operated Ca2+-channel blocker, had no effect. Propranolol, which blocks beta-adrenergic receptor as does verapamil, inhibited the transfection without severely damaging the protoplasts. These results suggested that a kind of receptor-operated Ca2+-channel was involved in the transport of PL-1 phage DNA into the cells and that the cell membrane might have a receptor structure somewhat similar to the beta-adrenergic receptor found in mammalian cells.

CD19 regulates B lymphocyte signaling thresholds critical for the development of B-1 lineage cells and autoimmunity

CD19 serves as a cell surface response regulator that establishes signaling thresholds critical for B lymphocyte development and activation. B lymphocytes from CD19-deficient mice are hyporesponsive to transmembrane signals, while B lymphocytes from mice that overexpress CD19 to even a small extent (25% increase) become hyperresponsive. The B-1 subpopulation of B lymphocytes is particularly sensitive to CD19 regulation, since their development is severely decreased in CD19-deficient mice. The effect of altered CD19 expression levels on the development of B cells was therefore examined using transgenic mice that express varying levels of cell surface CD19. In this study, immature B cells within the bone marrow of wild-type mice were found to specifically up-regulate CD19 expression levels by twofold as they mature, while CD5+ B cells within the spleen and peritoneum expressed even higher levels of CD19. The development of CD5+ B cells was severely decreased in CD19-deficient mice, while there was a linear correlation between increased CD19 expression levels and the increased frequency of CD5+ B cells within the peritoneum and spleen. In fact, CD5+ B cells became a major B lymphocyte population in mice that overexpressed CD19. Increased expression of CD19 also correlated with increased levels of endogenous anti-DNA Abs and rheumatoid factor. These results indicate that up-regulated expression of CD19 is functionally important for B cell development and that CD19 establishes signaling thresholds that regulate the generation of B-1 lymphocytes as well as the development of autoantibodies.

CD19 regulates B lymphocyte signaling thresholds critical for the development of B-1 lineage cells and autoimmunity

CD19 serves as a cell surface response regulator that establishes signaling thresholds critical for B lymphocyte development and activation. B lymphocytes from CD19-deficient mice are hyporesponsive to transmembrane signals, while B lymphocytes from mice that overexpress CD19 to even a small extent (25% increase) become hyperresponsive. The B-1 subpopulation of B lymphocytes is particularly sensitive to CD19 regulation, since their development is severely decreased in CD19-deficient mice. The effect of altered CD19 expression levels on the development of B cells was therefore examined using transgenic mice that express varying levels of cell surface CD19. In this study, immature B cells within the bone marrow of wild-type mice were found to specifically up-regulate CD19 expression levels by twofold as they mature, while CD5+ B cells within the spleen and peritoneum expressed even higher levels of CD19. The development of CD5+ B cells was severely decreased in CD19-deficient mice, while there was a linear correlation between increased CD19 expression levels and the increased frequency of CD5+ B cells within the peritoneum and spleen. In fact, CD5+ B cells became a major B lymphocyte population in mice that overexpressed CD19. Increased expression of CD19 also correlated with increased levels of endogenous anti-DNA Abs and rheumatoid factor. These results indicate that up-regulated expression of CD19 is functionally important for B cell development and that CD19 establishes signaling thresholds that regulate the generation of B-1 lymphocytes as well as the development of autoantibodies.

Intrapleural pirarubicin (4'-O-tetrahydropyranyladriamycin) for treatment of malignant pleural effusion

Pirarubicin (4'-O-tetrahydropyranyladriamycin), a new anthracyline derivative, was administered as a single agent into the pleural cavity of 42 patients (total 46 courses) with malignant pleural effusion at a dose of 20, 40, 60 or 80 mg/body. All 46 courses were evaluable for non-hematological toxicities. Fever and chest pain (> or = WHO grade 2) were seen in 67.4% and 13.0% of courses, respectively. Patients receiving a dose of 80 mg/body developed fever of > or = 39 degrees C in 45.5%, and chest pain lasting more than three days and requiring pentazocine more than three times in 36.4%. In contrast, patients receiving a dose of < or = 60 mg/body presented these toxicities in only 8.6% and 2.9%, respectively. Nausea-vomiting (> or = WHO grade 2) was observed in only 4.3% of the total 46 courses and alopecia was not observed. Thirty-eight courses (36 patients) were evaluable for hematological toxicities. Myelosuppression (leukocyte nadir count < or = 1900, WHO grade 3 or 4) was seen in four courses (10.5%), and thrombocytopenia (< or = 49,000, WHO grade 3 or 4) in only two (5.3%). Although the mean AUC (0-24) for pirarubicin in plasma during the four courses that produced myelosuppression was significantly higher than that during the 11 courses without myelosuppression, the difference in the mean dose was not significant. Furthermore, no significant correlation was shown between dose (mg/m2) and AUC in plasma. It is considered that myelosuppression is not a dose-related toxicity at a dose of 20-80 mg/body. The dose-limiting toxicity was fever or chest pain, although unexpected myelosuppression was also encountered. The maximum tolerated dose was 80 mg/body. With regard to clinical efficacy, the overall response rate was 73.7% in 38 evaluable courses (38 patients). The mean T(1/2) of pirarubicin concentration in pleural effusion and plasma was 22.1 h and 8.8 h, respectively. We recommend a dose of 40 or 60 mg/body pirarubicin for this pleurodesic treatment.

A comparison of children with suprasellar germ cell tumors and craniopharyngiomas: final height, weight, endocrine, and visual sequelae after treatment

BACKGROUND

Although treatment results of craniopharyngiomas and germ cell tumors in children have been reported extensively, the relationship between various posttreatment sequelae and the nature of the tumor is not well understood.

METHODS

From 1968-94, 47 children with 23 suprasellar germ cell tumors and 24 craniopharyngiomas were treated at Gunma University Hospital, Japan. Forty survivors were assessed with regard to Karnofsky scores, visual scores, final height, final weight, and other endocrine sequelae as long-term functional prognostic indicators.

RESULTS

Kaplan-Meier life-table estimates and Karnofsky scores were not significantly different between the two histologic groups. The visual function of survivors did not differ significantly at diagnosis. However, the final visual function following treatment in the germ cell tumor group was better than in the craniopharyngioma group (p < 0.05). Antidiuretic hormone secretion was significantly impaired at diagnosis in the germ cell tumor group (p < 0.0001). However, there was only a marginally significant difference in posttreatment persistent diabetes insipidus. Craniopharyngioma children were shorter and more obese at diagnosis (p < 0.02), and became much more obese than germinoma children with the same hormone therapy (p < 0.003), although the height difference became insignificant following growth hormone treatment.

CONCLUSIONS

Children with craniopharyngiomas tended to have more visual disturbances, increased dwarfism and obesity, and less diabetes insipidus than patients with germ cell tumors despite adequate therapy. The method of quantifying visual function may in itself be useful.

Effects of insulin on calcium metabolism and platelet aggregation

The influence of insulin on platelets in vitro has not been exhaustively investigated. To clarify whether insulin affects Ca2+ metabolism in platelets directly or through alteration of other systems regulating intracellular Ca2+ homeostasis, we examined the effect of insulin both alone and in combination with prostaglandin E1 on platelet aggregation and Ca2+ metabolism. Incubation of rat platelets with insulin reduced thrombin-induced Ca2+ influx but did not change thrombin-evoked release of Ca2+ from internal stores or the size of internal Ca2+ stores. The interactive effects of insulin with prostaglandin E1 were only additive, and insulin did not augment the effects of prostaglandin E1 on platelet Ca2+ metabolism. In contrast, insulin did not inhibit thrombin-induced platelet aggregation but did augment inhibition of platelet aggregation by prostaglandin E1. Our results suggest that insulin inhibits platelet function by both prostaglandin E1-dependent and -independent mechanisms.