Immunocytochemical evidence of common-ALL antigen in null-ALL

4 cases of acute lymphoblastic leukaemia (ALL), diagnosed as null-ALL by indirect immunofluorescence using monoclonal antibodies, were similarly investigated using a sensitive immunoperoxidase method. The Avidin-Biotin system was employed. The immunoenzymatic results were in agreement with those obtained with immunofluorescence techniques for all antigens except common-ALL (C-ALL). The C-ALL antigen, recognized by the J5 antibody, was detected only by the immunoperoxidase method on cell membranes of the 4 ALL. This paper discusses the possibility of false negative results in testing for C-ALL antigen by conventional indirect immunofluorescence as suggested by refined immunocytochemical screening. Moreover, the ability of the immunoperoxidase system to identify antigens on cell membranes, even at very low density, is discussed. The clinical significance of the presence of C-ALL antigen at weak intensity in cases of null-ALL is also considered.     

Immunocytochemical evidence for in vivo internalization of thyroliberin into rat pituitary target cells

The in vivo internalization of thyrotropin-releasing hormone (TRH) was studied by using a semiquantitative immunoelectron microscopic method. Pituitary glands of normal male rats intravenously injected with 100 ng TRH and sacrificed after 5-60 min were used. Ultrathin sections were obtained by cryoultramicrotomy of fixed pituitary glands. Pituitary cellular types were identified by appropriate antiserums. An antiserum specifically directed against TRH was used. TRH-like immunoreactivity due to endogenous TRH was observed in thyrotropes and prolactin cells, but never in somatotropes, gonadotropes or corticotropes. At the subcellular level, the reaction was detected within the cytoplasmic matrix, the secretory granules, and the nucleus but only occasionally at the plasma membrane. After in vivo injection of TRH, the immunocytochemical reaction was still restricted to thyrotropes and prolactin cells, increased with time elapsed after injection up to 15-30 min and then returned to basal intensity in cytoplasm, secretory granules, and nucleus, and became very frequent at the plasma membrane. These data provide evidence for endogenous TRH within thyrotropes and prolactin cells, i.e., in physiological target cells for TRH, and support the hypothesis that normal TRH target cells can, in vivo, internalize exogenous as well as endogenous TRH into several subcellular compartments including the nucleus.     

Ability of the CRF immunoreactive neurons of the paraventricular nucleus to produce a vasopressin-like material. Immunohistochemical demonstration in adrenalectomized guinea pigs and rats

In the paraventricular nucleus of normal or adrenalectomized colchicine-treated guinea pigs and rats, corticotropin-releasing factor (CRF), vasopressin (VP) and oxytocin (OX) immunoreactivities were compared. In the control animals, respective stainings for these three peptides are distinct. Adrenalectomy resulted in the appearance of a VP-like staining in most of the CRF-immunoreactive neurons whereas OX staining remained distinct. It is suggested that the CRF/VP coexistence reflects the synergistic role of the two peptides.     

Immunocytochemical evidence for differential distribution of gastrin forms using region-specific monoclonal antibodies

Immunocytochemical identification of cellular origins of different forms of gastrin in canine and human antral mucosa has been carried out using region specific monoclonal antibodies. Three types of gastrin cells were identified. The first type of cell was stained with both the C-terminal specific antibody of G17 and the N-terminal specific antibody of G17. The second type of cell was stained only with the C-terminal specific antibody of G17 but not with the N-terminal specific antibody of G17. The third type of cell was stained only with the N-terminal specific antibody of G17. From these findings we propose that the first type of cell contains gastrins with the amidated C-terminus of G17 such as component 1, G34, G17, or G14 as well as the free N-terminus of G17 such as G17, or C-terminal extended gastrins, the second type of cell contains gastrins only with the C-terminus of G17 but not with the N-terminus of G17 such as G34, or component 1, and the third type of cell contains C-terminal extended gastrins with intact N-terminus G17.     

Parathyroid hormone stimulates bone formation and resorption in organ culture: evidence for a coupling mechanism

We have developed an in vitro system, using embryonic chicken tibiae grown in a serum-free medium, which exhibits simultaneous bone formation and resorption. Tibiae from 8-day embryos increased in mean (+/- SD) length (4.0 +/- 0.4 to 11.0 +/- 0.3 mm) and dry weight (0.30 +/- 0.04 to 0.84 +/- 0.04 mg) during 12 days in vitro. There was increased incorporation of [3H]proline into hydroxyproline (120 +/- 20 to 340 +/- 20 cpm/mg of bone per 24 hr) as a measure of collagen synthesis, as well as a 62 +/- 5% increase in total calcium and 45Ca taken up as an indication of active mineralization. A physiologic concentration (1 pM) of parathyroid hormone was found to stimulate bone resorption over control levels in this system. Parathyroid hormone stimulated the release of [3H]hydroxyproline from the bone shafts but not from the cartilage ends, indicating the specificity of the response. With 1 pM parathyroid hormone we observed an acute inhibition of bone formation, followed (after 12-16 hr) by a chronic stimulation of bone formation during the 12-day incubation. Both mineral uptake and matrix formation were enhanced at approximately the same rate during the 12-day incubation. The chronic enhancement of formation required parathyroid hormone only for the initial 8-10 hr of incubation. These results could be explained by the production or release of a factor from bone to stimulate formation in response to the acute increase in resorption--a "coupling factor." Indeed, dialyzed culture medium conditioned by actively resorbing bones stimulated bone formation over controls when added to organ cultures at a 1:20 dilution. The factor is larger than 12,000 daltons as determined by dialysis. The factor is specific for the bone shaft and did not affect the cartilage ends.     

Immunocytochemical evidence for the presence of gamma 1-MSH-like immunoreactivity in pituitary corticotrophs and ACTH-producing tumours

The presence of gamma 1-MSH has been demonstrated in bovine neuro-intermediate lobe by biochemical methods, thus suggesting that this peptide is cleaved from the cryptic region of pro-opiocortin. In this study we report the localisation of gamma 1-MSH-like immunoreactivity in the adenohypophysis of man, ox, pig, dog and guinea-pig using immunocytochemical procedures at both light and electron microscope levels. Antisera recognising the C-terminal Arg-Phe-amide and the C-terminal penta-peptide-amide of gamma 1-MSH have been used throughout this study. The immunostaining was found in all endocrine cells of the pars intermedia (where present) and in scattered cells of the pars distalis identified as corticotrophs. No gamma 1-MSH immunoreactivity was detected in rat adenohypophysis. In addition, 7 ACTH-producing tumours (1 pituitary adenoma and 6 ectopic) were investigated and shown to contain gamma 1-MSH immunoreactive cells.     

Immunocytochemical localization of cyclic GMP: Light and electron microscope evidence for involvement of neuroglia

Guanosine 3',5'-cyclic monophosphate (cGMP) immunoreactivity in the rat's cerebellum was studied with light and electron microscopy by the indirect fluorescence method and the peroxidase-antiperoxidase method. Labeled cells included neuroglial cells in the cerebellar cortex, white matter, and deep nuclei; some stellate and basket cells in the cortex; and some large neurons in the deep nuclei. No evidence was found for sagittal microzonation in the cGMP distribution. In the labeled cells, cGMP immunoreactive sites were localized to surface membranes, organelles, and the cytoplasmic matrix. Specificity was indicated by the same pattern of labeling after treatment with cGMP immunoglobulin that had been adsorbed with adenosine 3',5'-cyclic monophosphate (cAMP) and by the failure to label after treatment with normal rabbit sera or with cGMP immunoglobulin that had been adsorbed with 1 mM cGMP. Cerebella treated with cAMP antisera, however, showed immunoreactivity in Purkinje cells, granule cells, and Golgi cells in addition to neuroglia in cortex and deep nuclei. Sequential norepinephrine and glutamate superfusions generally intensified cGMP immunoreactivity, not only in neuroglial cells but also in the background. Under these conditions some Purkinje cells and some granule cells were also labeled. Increased cGMP immunoreactivity was also obtained by treatment with harmaline, gamma-aminobutyric acid and aminooxyacetic acid, muscimol, gamma-aminobutyric acid, or apomorphine in order of decreasing effectiveness. Serotonin and colchicine produced no detectable increase of cGMP immunoreactivity above normal, and diazepam and sodium pentobarbital decreased it. In these experiments, diethyl ether was preferable to sodium pentobarbital for anesthesia on account of the depressive action of the latter on cGMP immunoreactivity. Thus, drugs that increase cerebellar activity enhance cGMP levels, whereas those that decrease cerebellar activity decrease cGMP levels. However, it is not clear whether these fluctuations in cGMP levels are a direct consequence of neurotransmitter function or are sequelae to other related events. The present study suggests that some neurons and many neuroglial cells are the major sites of cGMP in the cerebellum.     

Immunocytochemical and pharmacological evidence for an intrinsic cholinomimetic system modulating prolactin and growth hormone release in rat pituitary

Pituitary cells were cultured as three-dimensional reaggregates in serum-free chemically defined medium supplemented with different concentrations of dexamethasone. Immunostaining of the cells using a polyclonal antiserum and three monoclonal antibodies raised against choline acetyl transferase (CAT), revealed the presence of CAT immunoreactivity in 4-10% of anterior pituitary cells depending on the antibody used. CAT immunoreactivity was also found in freshly dispersed anterior pituitary cells. CAT-immunoreactive cells could be enriched on BSA and Percoll gradients and codistributed with ACTH-immunoreactive cells in these gradients. Perifusion of the aggregates with the potent muscarinic receptor antagonist atropine (Atr) resulted in a dose-dependent (0.1-100 nM) increase in both basal PRL and GH secretion; the response was dependent on the dexamethasone concentration in the culture medium. A similar response to Atr was observed in organ-cultured pituitaries. The specificity of the Atr effect was supported by the findings that the potent and highly specific muscarinic receptor blocker dexetimide showed a similar action, whereas its inactive enantiomer levetimide and the nicotinic receptor blocker hexamethonium failed to do so. Two other muscarinic antagonists, benzatropine and pirenzepine, showed a dose-dependent hormone-releasing action similar to that of Atr, but were less potent than the latter. Pirenzepine was only effective at high molar concentrations, suggesting that an M2 muscarinic receptor subtype was mediating the present phenomenon. Atr also potentiated GH release stimulated by the beta-adrenergic agonist isoproterenol and PRL release stimulated by vasoactive intestinal peptide, but had no effect on GRF-stimulated GH release. The choline uptake blocker hemicholinium abolished the effect of Atr on GH and PRL release. These data suggest that certain pituitary cells can express CAT activity and that these cells exert a tonic inhibitory activity on GH and PRL release which is mediated by a cholinomimetic substance, possibly acetylcholine, through a muscarinic receptor.     

Immunocytochemical evidence for vasopressin and oxytocin pathways in the hypothalamo-hypophyseal axis of the camel (Camelus dromedarius)

Immunoperoxidase staining was applied to the hypothalamus and posterior pituitary of the camel. Vasopressin and oxytocin cells and fibers were identified in different nuclei of the hypothalamus. Immunoreactive fiber tracts were followed to the median eminence and the posterior pituitary. In the median eminence, two different pathways were found for vasopressin, one passing to the posterior lobe and the other contacting capillaries of the portal system. The oxytocin antiserum stained one unique pathway in the internal zone on its way to the posterior pituitary. The two immunoreactivities were shown in the posterior lobe of the pituitary, vasopressin staining being the more intense. Relations between these data and the physiology of the camel are discussed.     

Immunocytochemical evidence for inducible nitric oxide synthase and cyclooxygenase-2 expression with nitrotyrosine formation in human hibernating myocardium

Background: Myocardial hibernation may result from repetitive episodes of transient ischaemia leading to prolonged dysfunction. Inducible nitric oxide synthase (iNOS) expression has been demonstrated in animals following brief, non-lethal ischaemia-reperfusion injury. We therefore, hypothesised that in human hibernating myocardium: 1) iNOS would be present; 2) the reaction of nitric oxide and superoxide would form the strong oxidant peroxynitrite; 3) that this process would be accompanied by the expression of cyclooxygenase-2 (Cox-2) which interacts with NOS and whose products could further affect myocardial function. Method and results: In sixteen patients with coronary artery disease (CAD), left ventricular biopsies were obtained from chronically dysfunctional segments subtended by a stenotic artery (> 75 %) and shown to be viable by ¹⁸F-fluorodeoxyglucose positron emission tomography. Comparison was made with myocardial biopsies (n = 8) from normally contracting myocardium in patients undergoing coronary surgery, from unused transplant donors and at post-mortem. Regional wall motion score improved in all patients 6 months post-revascularisation (from 2.7 ± 0.7 to 1.5 ± 0.5; p < 0.001), confirming hibernation. Immunocytochemistry localized reactivity to iNOS, Cox-2 and nitrotyrosine (a marker of peroxynitrite formation) to cardiomyocytes from hibernating segments. No difference in reactivity to endothelial NOS was seen between hibernating and control cardiomyocytes. Conclusion: Cox-2 and iNOS are co-expressed in hibernating myocardium with nitrotyrosine suggesting nitric oxide production and peroxynitrite formation. We propose that this is secondary to ischaemia-reperfusion and that the products of these enzymes may have consequences for myocardial contractile function and survival. Received: 11 February 2002, Returned for revision: 14 February 2002, Revision received: 4 March 2002, Accepted: 11 March 2002     

Isotopic evidence for primordial molecular cloud material in metal-rich carbonaceous chondrites

The short-lived ²⁶Al radionuclide is thought to have been admixed into the initially ²⁶Al-poor protosolar molecular cloud before or contemporaneously with its collapse. Bulk inner Solar System reservoirs record positively correlated variability in mass-independent ⁵⁴Cr and ²⁶Mg*, the decay product of ²⁶Al. This correlation is interpreted as reflecting progressive thermal processing of in-falling ²⁶Al-rich molecular cloud material in the inner Solar System. The thermally unprocessed molecular cloud matter reflecting the nucleosynthetic makeup of the molecular cloud before the last addition of stellar-derived ²⁶Al has not been identified yet but may be preserved in planetesimals that accreted in the outer Solar System. We show that metal-rich carbonaceous chondrites and their components have a unique isotopic signature extending from an inner Solar System composition toward a ²⁶Mg*-depleted and ⁵⁴Cr-enriched component. This composition is consistent with that expected for thermally unprocessed primordial molecular cloud material before its pollution by stellar-derived ²⁶Al. The ²⁶Mg* and ⁵⁴Cr compositions of bulk metal-rich chondrites require significant amounts (25–50%) of primordial molecular cloud matter in their precursor material. Given that such high fractions of primordial molecular cloud material are expected to survive only in the outer Solar System, we infer that, similarly to cometary bodies, metal-rich carbonaceous chondrites are samples of planetesimals that accreted beyond the orbits of the gas giants. The lack of evidence for this material in other chondrite groups requires isolation from the outer Solar System, possibly by the opening of disk gaps from the early formation of gas giants.Low-mass stars like our Sun form by the gravitational collapse of the densest parts of molecular clouds comprising stellar-derived dust and gas. Collapsing clouds swiftly evolve into deeply embedded protostars that rapidly accrete material from their surrounding envelopes via a protoplanetary disk (1), in which planetesimals and planetary embryos form over timescales of several million years (2). Chondritic meteorites (chondrites) are fragments of early-formed planetesimals that avoided melting and differentiation and, therefore, provide a record of the earliest evolutionary stages of the Sun and its protoplanetary disk. Most chondrites contain calcium−aluminum-rich inclusions (CAIs) and chondrules, which formed by high-temperature processes that included evaporation, condensation, and melting during short-lived heating events (3). CAIs represent the oldest dated solids and, thus, define the age of the Solar System at 4,567.3 ± 0.16 Ma (4). It is inferred that CAIs formed near the proto-Sun during a brief time interval (<0.1 My) and record transient variability in the initial abundance of the stellar-derived short-lived ²⁶Al radionuclide (²⁶Al decays to ²⁶Mg with a half-life of 0.705 My) in the innermost protoplanetary disk (5–7). Following their formation, CAIs were transported to large radial distances (8). Chondrule formation started contemporaneously with CAIs and continued for several million years (4). Chondrules appear to have formed in different disk regions and sampled a wider range of radial distances from the Sun than CAIs (3). Collectively, chondritic components provide time-sequenced samples allowing us to probe the composition of the disk material that accreted to form planetesimals and planets.Unraveling the accretion regions of planetesimals is critical for understanding the dynamical evolution of the protoplanetary disk, including radial mass transport processes. However, the location of the accretion region(s) of the most primitive planetesimals represented by the carbonaceous chondrites is poorly understood. According to a dynamical model (9), carbonaceous chondrite parent bodies (C-, P-, and D-type asteroids) accreted between and beyond the formation regions of the giant planets, and were implanted in the main asteroid belt during the outward migration of Jupiter. However, the inferred deuterium/hydrogen (D/H) ratios of water in extensively aqueously altered CI (Ivuna type) and CM (Mighei type) carbonaceous chondrites are distinct from those of Oort Cloud and Jupiter family comets as well as Saturn’s moon Enceladus, implying that these bodies formed in different regions (10). Based on these observations, a competing model proposes that CI and CM chondrite parent bodies accreted in the inner Solar System, possibly close to the main asteroid belt (10, 11).In this work, we aim to constrain the chondrite accretion regions by combining high-precision magnesium and chromium isotope measurements of bulk chondrites and their components. In the inner Solar System, bulk planetary materials with solar or near-solar ²⁷Al/²⁴Mg ratios record positively correlated variability in μ²⁶Mg* and μ⁵⁴Cr (Fig. 1). This correlation is interpreted as reflecting progressive thermal processing of in-falling ²⁶Al-rich molecular cloud material, which resulted in preferential loss by sublimation of thermally unstable and isotopically anomalous presolar carriers, producing residual isotopic heterogeneity (12–15). In this model, the correlated μ²⁶Mg*−μ⁵⁴Cr array represents the unmixing of distinct dust populations with contrasting thermal properties, namely unmixing of old, galactically inherited homogeneous dust from a young supernovae-derived dust component formed shortly before or during the evolution of the giant molecular cloud structure parental to the protosolar molecular cloud core.Open in a separate windowFig. 1.Inner Solar System μ²⁶Mg*–μ⁵⁴Cr correlation. The μ-notation reflects the deviation in parts per millions (ppm) of the internally normalized ²⁶Mg/²⁴Mg and ⁵⁴Cr/⁵²Cr ratios from the terrestrial compositions. Uncertainties reflect the external reproducibility or internal errors, whichever is larger. The μ⁵⁴Cr uncertainties are typically smaller than symbols. AOA, amoeboid olivine aggregates; EC, enstatite chondrites; OC, ordinary chondrites; RC, Rumuruti chondrites. Data are from ref. 13 and this study. The μ⁵⁴Cr and μ²⁶Mg* compositions of the ²⁶Al-free and thermally unprocessed molecular cloud material, including their uncertainties, are defined by CI chondrites and the initial μ²⁶Mg* value of the Solar System (13). AOA and CAIs represented here are objects that formed with the canonical ²⁶Al/²⁷Al of ∼5 × 10⁻⁵. Although CI chondrites are commonly viewed as reflecting the bulk Solar System composition for most elements, it is unclear whether this assumption is correct for the μ²⁶Mg* and μ⁵⁴Cr values. This can be tested through high-precision Mg and Cr isotope measurements of the Sun, which is currently not possible at a level of precision relevant to our discussion. See SI Appendix, Fig. S8, for additional information with respect to the end-member compositions considered in the model.Planetesimals formed in the outer Solar System could have accreted a significant fraction of primordial and, hence, thermally unprocessed molecular cloud matter. This material may reflect the nucleosynthetic makeup of the molecular cloud before the last addition of stellar-derived ²⁶Al. The least thermally processed meteorites, CI carbonaceous chondrites, contain high abundances of presolar grains and record the highest level of nucleosynthetic enrichment for nuclides such as μ⁵⁴Cr among bulk planetary materials (12, 16). Thus, CI chondrites provide a lower limit for the average μ⁵⁴Cr value of thermally unprocessed molecular cloud material. Primordial molecular cloud material unpolluted by ²⁶Al is expected to have a μ²⁶Mg* value consistent with the Solar System initial composition, which is inferred to be −20.4 ± 2.9 ppm relative to CI chondrites (13). Therefore, unlike inner Solar System objects, the isotopic signature of the thermally unprocessed and ²⁶Al-poor primordial molecular cloud matter is expected to show a decoupling between their μ²⁶Mg* and μ⁵⁴Cr values (Fig. 1).     

Immunocytochemical and physiological evidence of a synapse between dopamine- and luteinizing hormone releasing hormone-containing neurons in the ewe median eminence

Immunocytochemical labeling revealed that the arcuate nucleus (ARN) of the ewe's hypothalamus contains numerous tyrosine hydroxylase (TH)-positive neurons, that appear to lack dopamine-beta-hydroxylase (DBH)-like immunoreactivity. Axons of these presumed dopaminergic neurons converge in the median eminence (ME) with Luteinizing Hormone Releasing Hormone (LHRH)-containing axons originating mostly from neurons situated in the medial preoptic area. Electron microscopic double labeling revealed synaptic contacts between TH-positive presynaptic profiles and LHRH-containing postsynaptic elements. Samples of ME, ARN, paraarcuate and lateral hypothalamus were dissected and incubated to assess LHRH release and tissue content. Only ME-LHRH release was significantly reduced in the presence of dopamine (DA). All other regions released equal amounts with and without DA. Thus, a presynaptic dopaminergic inhibition of LHRH-containing axons at the level of the ME might contribute to the regulation of LHRH release into the portal vessels.     

Immunocytochemical evidence for the colocalization of neurotensin/xenopsin- and gastrin/caerulein-immunoreactive substances in Xenopus laevis gastrointestinal tract

Distribution and association of neurotensin (NT)- and xenopsin (XP)-like peptides were investigated using immunocytochemical techniques in the amphibian gut. Antisera against both groups of peptides showed an identical distribution pattern of NT- and XP-positive cells in Xenopus laevis gastrointestinal tract. Immunolabeling of consecutive semithin sections revealed the coexistence of NT- and XP-like substances within cells of the stomach and small intestine. Recent reports of the colocalization of XP-like material with gastrin in mammalian G cells led us to study the association of NT/XP-like peptides with members of the gastrin/cholecystokinin (CCK)/caerulein (G/C) family in amphibians. The data obtained from immunolabeling serial sections with NT/XP-specific and G/C-specific antisera show that in some intestine NT/XP- and G/C-like peptides do exist in the same cells. In the stomach, however, G/C-like material is confined to endocrine cells of the antral region, while NT/XP-like substances occur in distinct cells accumulating in cardial glands but absent in the pyloric glands. Our findings thus indicate that in amphibian gastrointestinal tract there is some association between the regulatory peptide families NT/XP and G/C, similar to mammals. The regional distribution of both hormone families, however, is different from that in mammals.     

Immunocytochemical and ultrastructural evidence for supra- and subesophageal localization of the dorsal-body cells of the snail Helix aspersa

Dorsal-body endocrine cells (DBEC) of the snail were studied by means of immunocytochemical and electron microscopic methods at different times of the reproductive cycle. They specifically bind the anti-methionine-enkephalin (vertebrate--opioid-pentapeptide) antibody and are located not only near the cerebral ganglia but also in the connective tissue surrounding the subesophageal ganglia. Ultrastructural characteristics of these subesophageal cells, however, confirm their clear identity with the previously described supraesophageal cells. The quantitative variations of their immunoreactive content allow us to postulate a likely involvement in reproductive physiology (mating and egg laying). These observations prove that the distribution of the classical "dorsal-body cells" is more extensive than has been admitted until now and that they synthesize methionine-enkephalin-like substance(s).     

Drug-induced elevation of vasopressin-like immunoreactivity in Raphe and septal regions of the mouse CNS

Increases and decreases in the concentration or activity of vasopressin (VP) in mice result in facilitations and deficits in avoidance performance, respectively. An experiment was conducted to test the hypothesis that elevations in the central nervous system concentration of VP result from doses of d-amphetamine, strychnine sulfate and physostigmine known to induce facilitations of avoidance performance. An immunohistofluorescent technique was used to determine whether performance-facilitating doses of the three drugs elevated VP levels in a number of brain structures. A performance-facilitating dose of each of the three drugs was found to increase VP-like immunoreactivity in the dorsal raphe and lateral septum, but not in the substantia nigra, dentate gyrus or central amygdaloid nucleus.     

Trypsin liberates an arginine vasopressin-like peptide and neurophysin from a Mr 20,000 putative common precursor.

Although the hypothesis that vasopressin and its associated neurophysin are synthesized together in one macromolecular common precursor was put forward more than a decade ago, direct conformation of this hypothesis has been lacking. A [35S]cysteine-labeled putative precursor for vasopressin-related neurophysin (Mr 20,000, pI 6.1) has been isolated from the supraoptic nuclei of rats. This precursor was subjected to limited proteolysis with trypsin which produced a Mr 10,000 protein and peptide products. The former was identified as neurophysin on the basis of its pH-dependent affinity for vasopressin and its behavior in isoelectric focusing systems (pI 4.6-4.8). The tryptic peptides proved to be vasopressin-like because they: (i) were rich in cysteine, (ii) comigrated with vasopressin on gel filtration columns in 6 M guanidine HCl, (iii) bound to a neurophysin-Sepharose affinity column at pH 5.7, and (iv) were recognized by antibodies against vasopressin. These data on the Mr 20,000, pI 6.1 protein represent direct experimental evidence for a candidate for the common precursor of vasopressin and neurophysin. We propose that this common precursor be called "propressophysin."     

Immunocytochemical evidence for the expression of GST1, GST2, and GST3 gene loci for glutathione S-transferase in human lung

Immunocytochemical studies demonstrate that significant amounts of glutathione S-transferase (GST) are associated with alveoli and bronchioles of human lung. The immunofluorescence in human lung sections was observed with the antibodies which were raised against GSTω and GSTα-ɛ of human liver and GSTπ of human placenta indicating that the isoenzymes corresponding to three gene loci, GST1, GST2, and GST3 are present in human lung. Presence of GST isoenzymes in significant amounts in bronchioles and alveoli of human lung indicate that these isoenzymes may play an important role in the detoxification of xenobiotics as well as in combating oxidative stress through glutathione peroxidase II activity.