Structures of bacitracin A and isolated congeners: sequencing of cyclic peptides with blocked linear side chains by electrospray ionization mass spectrometry

The bacitracin antibiotic complex consists principally of bacitracin A, a peptide antibiotic containing seven amino acid residues in a ring and five amino acid residues in a blocked side chain, together with a mixture of minor components presumably related but of unknown structures. A preparative high-performance liquid chromatographic method was developed for isolating the minor components A2, B1 and B2 which were then characterized by amino acid analysis, exact mass fast atom bombardment (FAB) mass spectrometry, FAB tandem mass spectrometry (MS/MS) and electrospray ionization (ESI) mass spectrometry. For bacitracins A (MW 1421), A2 (MW 1421), B1a (MW 1407), B1b (MW 1407), B2 (MW 1407) and F (MW 1419), the side chain sequences were determined by ESI MS/MS and ESI nozzle-skimmer collision-induced dissociation (CID) mass spectrometry and the ring sequences elucidated by ESI nozzle-skimmer CID MS/MS. Relative to bacitracin A, bacitracin A2a has the modified isoleucine residue at position 1 replaced by a modified allo-isoleucine residue, bacitracin B1a has the isoleucine residue at position 8 replaced by a valine residue, bacitracin B1b has the isoleucine residue at position 5 replaced by a valine residue and bacitracin B2 has the modified isoleucine residue at position 1 replaced by a modified valine residue. FAB tandem mass spectra were shown to be consistent with the above structural assignments for the isolated bacitracin components. Structures were also proposed for the trace bacitracin components C1 (MW 1393) and D1 (MW 1379) using ESI MS/MS data obtained from the analysis of the bacitracin complex without isolation.

Radioimmunoguided surgery in gastric cancer using 131-I labeled monoclonal antibody 3H11

A clinical trial of radioimmunoguided surgery (RIGS) using 131-I labeled monoclonal antibody (MAb) 3H11 was performed on 25 cases with gastric cancer in this study. The results showed that the route of the administration of radiolabeled MAb is the key point of successful RIGS for gastric cancer. The RIGS in 19 cases in the group of submucosal injection via endoscope was very satisfying. For the detection of metastatic lymph nodes, the sensitivity rate of RIGS was 99.2% (118/119), the specificity, 97.7% (43/44), and the accuracy 98.8% (161/163). The accuracy rate in detecting tumor infiltration of the gastric wall was 95.9% (94/98), the sensitivity 94.6% (35/37), and the specificity 96.7% (59/61). Thus, the use of RIGS may improve the radical resectability rate and possibly the overall survival rate in patients with gastric cancer.

[Thumb and finger reconstruction by anastomosing the digital arteries of the toe to finger transplant]

In a series of 295 cases of toe-to-finger reconstruction, 30 cases with 40 digits were reconstructed by arterial anastomosis between digital arteries of the toe transplant and the recipient thumb or fingertoe. Among them 5 thumbs were reconstructed by the distal segment of the big toe. 11 thumbs (10 cases), 15 fingers (8 cases) and 1 case with concomitant thumb and 3 fingers were reconstructed by toe transfer. Six cases of thumb pulp defect were also reconstructed by the big toe pulp transfer. The anastomosis of digital arteries instead of dorsalis pedis artery and radial artery and saphenous vein with cephali vein to re-establish circulation is an innovation and has the advantages of simplifying the operative procedure, minimizing operative trauma, reducing operation time, attenuating patients suffering, and obtaining good appearance and function after reconstruction. Besides the operation would not be hindered by anatomical variations of the artery and would reduce blood supply disturbance of the donor foot.

Sequence of the murine Huntington disease gene: evidence for conservation, alternate splicing and polymorphism in a triplet (CCG) repeat [corrected]

Huntington disease (HD) is associated with significant expansion of a CAG trinucleotide repeat within a novel gene. However, no clues to the function of this gene were apparent by sequence alignment to other proteins. We have therefore sought to identify the mouse gene (hd) as a first step in the development of an animal model for HD to provide insights into the molecular pathogenesis of this disease. Here, we report the sequencing of cDNA clones spanning 9,992 nucleotides encoding the murine HD homologue (hd), which exhibits 90% peptide sequence identity, including conservation of the CAG and adjacent CCG repeats. In addition, we show that the CCG is polymorphic in the mouse. Sequence analysis provides strong evidence that the first in frame methionine 5' to the CAG repeat, is the translational start site, for both the mouse and human transcript. As in human, the gene appears expressed in the mouse as 2 large transcripts. We observe evidence for alternate splicing of the hd gene in mouse tissues which would predict two protein products differing by 480 amino acid residues with a molecular mass difference of approximately 54 kilodaltons.

Functional significance of lysine 1423 of neurofibromin and characterization of a second site suppressor which rescues mutations at this residue and suppresses RAS2Val-19-activated phenotypes

Lysine 1423 of neurofibromin (neurofibromatosis type I gene product [NF1]) plays a crucial role in the function of NF1. Mutations of this lysine were detected in samples from a neurofibromatosis patient as well as from cancer patients. To further understand the significance of this residue, we have mutated it to all possible amino acids. Functional assays using yeast ira complementation have revealed that lysine is the only amino acid that produced functional NF1. Quantitative analyses of different mutant proteins have suggested that their GTPase-activating protein (GAP) activity is drastically reduced as a result of a decrease in their Ras affinity. Such a requirement for a specific residue is not observed in the case of other conserved residues within the GAP-related domain. We also report that another residue, phenylalanine 1434, plays an important role in NF1 function. This was first indicated by the finding that defective NF1s due to an alteration of lysine 1423 to other amino acids can be rescued by a second site intragenic mutation at residue 1434. The mutation partially restored GAP activity in the lysine mutant. When the mutation phenylalanine 1434 to serine was introduced into a wild-type NF1 protein, the resulting protein acquired the ability to suppress activated phenotypes of RAS2Val-19 cells. This suppression, however, does not involve Ras interaction, since the phenylalanine mutant does not stimulate the intrinsic GTPase activity of RAS2Val-19 protein and does not have an increased affinity for Ras proteins.

Prodepin: a new product of the adrenomedullin (ADM) gene has systemic vasodilator activity

The purpose of the present study was to investigate the effects of products of the ADM gene other than ADM on systemic hemodynamics in the anesthetized rat, rabbit, piglet, cat and dog. Bolus intravenous (i.v.) injections of rat proADM22-41 (3-30 micrograms) significantly decreased systemic arterial pressure (SAP) and systemic vascular resistance in the anesthetized rat. Unlike ADM, rat proADM22-41 markedly increased cardiac output in the rat. Bolus i.v. injections of human proADM22-41 up to 500 micrograms had not effect in all species studied and rat proADM22-41 had no effect in species other than the rat. The present data suggest that rat proADM22-41 is a novel product of the ADM gene other than ADM and possesses marked systemic vasodilator activity. The present data also suggest that the hemodynamic activity of this peptide is species specific.

MK-801 (dizocilpine) protects the brain from repeated normothermic global ischemic insults in the rat

We investigated the neuroprotective potential of MK-801 (dizocilpine), a noncompetitive N-methyl-D-aspartate (NMDA) antagonist, in the setting of three 5-min periods of global cerebral ischemia separated by 1-h intervals in halothane-anesthetized rats. Each ischemic insult was produced by bilateral carotid artery occlusions plus hypotension (50 mm Hg). Brain temperature was maintained at normothermic levels (36.5-37.0 degrees C) throughout the experiment. MK-801 (3 mg/kg) (n = 6) or saline (n = 6) was injected intraperitoneally 45 min following the end of the first ischemic insult. Following 7-day survival, quantitative neuronal counts of perfusion-fixed brains revealed severe ischemic damage in hippocampal CA1 area, neocortex, ventrolateral thalamus, and striatum of untreated rats. By contrast, significant protection was observed in MK-801-treated rats. In area CA1 of the hippocampus, numbers of normal neurons were increased 11- to 14-fold by MK-801 treatment (p < 0.01). The ventrolateral thalamus of MK-801-treated rats showed almost complete histologic protection, and neocortical damage was reduced by 71% (p < 0.01). The degree of MK-801 protection of striatal neurons was less complete than that seen in other vulnerable structures, amounting to 63% for central striatum (p = 0.02, Mann-Whitney U test) and 48% in the dorsolateral striatum (NS). A repeated-measures analysis of variance demonstrated a highly significant overall protective effect of MK-801 treatment (F1,10 = 37.2, p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Differential 3' polyadenylation of the Huntington disease gene results in two mRNA species with variable tissue expression

Recently a novel gene containing a CAG trinucleotide repeat that is expanded on HD chromosomes has been identified(1). This gene was shown to detect a single transcript of 10-11 kb by RNA hybridization. We have however, previously identified three cDNAs which are part of the same gene that have been shown to detect two distinct transcripts of 10 kb and one that is significantly larger(2,3). These different mRNA species could be due to use of alternate transcription start sites, alternate splicing or selection of different polyadenylation sites. We have identified cDNA clones spanning the HD gene including two (HD12 and HD14) that share identical protein coding sequences but differ in size and sequence of their 3' untranslated region. HD14 has 3,360 base pairs of additional sequence distal to the previously published 3' end (1). RNA hybridization has revealed that the larger 13.7 kb fragment is the predominant transcript in human brain. cDNA fragments unique to HD14 detected only the larger transcript. Sequence analysis identified two different putative polyadenylation sequences at position 10,326 and 13,645 of the HD14 cDNA. These findings indicate that the two observed mRNA species originate from a single gene and that differential polyadenylation leads to transcripts of different size. The relative increased abundance of the larger transcript in human brain may provide some insights into the mechanism by which a widely expressed gene may exert tissue specific effects.

Group B streptococcal neuraminidase is actually a hyaluronidase

The extracellular group B streptococcal enzyme described in numerous reports as a neuraminidase is really a hyaluronidase. Over the past 25 years, the enzyme was routinely assayed with bovine submaxillary mucin as the substrate and by the thiobarbituric acid procedure to measure released sialic acid. Characterization of the actual compound released by the enzyme revealed it to be an alpha,beta-unsaturated derivative of hyalobiuronic acid that was derived from hyaluronic acid contaminating the mucin preparation. Previous reports describing an association of elevated levels of extracellular neuraminidase with virulent strains of group B streptococci must be reevaluated with the recognition that the enzyme is really a hyaluronidase.

Acquired amegakaryocytic thrombocytopenic purpura with a Philadelphia chromosome

A 30-year-old Chinese man with acquired amegakaryocytic thrombocytopenic purpura (AATP) and a Ph chromosome is reported. At presentation, he had severe thrombocytopenia resulting in epistaxis, gingival bleeding, and ecchymoses, while other hematologic values were within the normal range. Bone marrow aspiration showed no megakaryocytes, with a normal appearance of erythroblastic and granulopoietic series. He failed to respond to prednisone treatment, and underwent a progress from isolated thrombocytopenia to full pancytopenia. At last he died of spontaneous intracranial hemorrhage. An in vitro culture for granulocyte-macrophage precursors showed very few colonies. Karyotypic analysis revealed a standard Ph chromosome translocation, t(9;22)(q34;q11), in the majority of bone marrow cells. Southern blot analysis using a 3' bcr-HE probe didn't detect a rearrangement within the bcr DNA sequence. This patient, in fact, was a myelodysplastic disorder, initially presenting as AATP. The diagnosis of chronic myelogenous leukemia was excluded on the basis of clinical and hematologic findings. The heterogeneity of Ph chromosome in myelodysplastic syndrome is discussed.

The relationship between trinucleotide (CAG) repeat length and clinical features of Huntington's disease

Huntington's disease (HD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene. We have assessed 360 HD individuals from 259 unrelated families and found a highly significant correlation (r = 0.70, p = 10(-7)) between the age of onset and the repeat length, which accounts for approximately 50% of the variation in the age of onset. Significant associations were also found between repeat length and age of death and onset of other clinical features. Sib pair and parent-child analysis revealed that the CAG repeat demonstrates only mild instability. Affected HD siblings had significant correlations for trinucleotide expansion (r = 0.66, p < 0.001) which was not apparent for affected parent-child pairs.

A transcription map of the region containing the Huntington disease gene

A transcription map of the Huntington disease gene region was generated by a direct cDNA selection strategy using genomic DNA from the 4p16.3 region surrounding the D4S95 and D4S127 loci. A total of 58 cDNA fragments were obtained from cDNAs derived from fetal brain, frontal cortex, liver and bone marrow following hybridization to overlapping YACs from this region. These cDNA clones were aligned into transcription units by hybridization to specific mRNAs, by sequence overlap and by physical mapping onto overlapping YAC clones. Nine separate transcription units spanning approximately one megabase were detected by RNA hybridization. They represent a minimum number of genes in this region and do not include those genes expressed specifically in tissues not used for the hybridization. The transcription map that is provided by the cDNA segments will lead to the generation of a detailed gene map of this region.

Identification of an Alu retrotransposition event in close proximity to a strong candidate gene for Huntington's disease

Huntington's disease (HD) is a late-onset autosomal dominant neuropsychiatric disorder presenting in mid-adult life with personality disturbance and involuntary movements, cognitive and affective disturbance, and inexorable progression to death. The underlying genetic defect has been mapped to chromosomal band 4p16.3 (refs 2, 3). Analysis of specific recombination events in some families with HD has further refined the location of the HD defect to a 2.2 megabase DNA interval. Using a direct complementary DNA selection strategy we have identified at least seven transcriptional units within the minimal region believed to contain the HD gene. Screening with one of the cDNA clones identified an Alu insertion in genomic DNA from two persons with HD which showed complete cosegregation with the disease in these families but was not found in 1,000 control chromosomes. Two genes including the previously identified alpha-adducin gene and another that encodes for a 12-kilobase transcript, map in close proximity to the Alu insertion site. The 12-kilobase transcript should be regarded as a strong candidate for the HD gene.

Vaccination of bovines against Schistosomiasis japonica with cryopreserved-irradiated and freeze-thaw schistosomula

Four laboratory tests and one field trial with cryopreserved irradiated (CI) schistosomula vaccine and a freeze-thaw (F/T) vaccine against bovine Schistosomiasis japonica were carried out in 1979 and 1980 with the following results: (1) Single intradermal vaccination in buffalo calves each with 10,000 20 krad CI Schistosomula plus 1 ml BCG gave 62% worm reduction (P < 0.05). Using the same protocol 55% worm reduction (P < 0.01) was obtained in cattle. (2) Buffalo calves immunized twice, at a 1.5 month interval, with 10,000 and 20,000 CI schistosomula, respectively, resulted in a worm reduction 65%. (3) In a preliminary field trial with 10,000 CI schistosomula plus 1 ml BCG resulted in a worm reduction of 53% in buffalo calves. (4) Intradermal vaccination of 30,000 F/T schistosomula with 1 ml BCG was also tried in cattle and revealed a worm reduction of 57% but increasing the number of vaccinations did not improve the protective effect. (5) Evidence regarding the effects of immunization with CI vaccine in buffaloes and F/T vaccine in cattle, on the number of eggs and miracidia and that of female worms themselves was obtained. (6) Immune responses, cellular and humoral, elicited in buffaloes vaccinated with CI schistosomula were detected by means of Lymphocyte Transformation Assay and Enzyme Linked Immunosorbent Assay.

Complex karyotypic abnormalities including t(8;22) in a patient with chronic lymphocytic leukemia

The case of a 49-year-old Chinese man with B-cell chronic lymphocytic leukemia (B-CLL) is presented. Complex karyotypic abnormalities comprising t(8;22)(q24;q11), trisomy 7, a deletion of 11q, and two small marker chromosomes were observed in PWM-stimulated cultures of his peripheral blood cells. To our knowledge, this is the first report of a t(8;22) in CLL.

Geographical clusters of dengue virus type 2 isolates based on analysis of infected cell RNA by the chemical cleavage at mismatch method

Genetic variation in 12 strains of dengue virus type 2, isolated from several epidemic areas in different years, was studied by chemical cleavage at mismatched cytosine in DNA:RNA heteroduplexes. End-labelled cDNA probes derived from the E and NS2A genes of the New Guinea C strain were hybridized to total RNA extracted from cells infected by individual isolates. Following modification of mismatched cytosine by hydroxylamine and nucleic acid strand cleavage by piperidine, the resulting fragments of radiolabelled probe were analysed by electrophoresis and autoradiography. The patterns of bands generated corresponded to the geographical groupings of the isolates. Thus this method is suitable in epidemiological studies for rapidly surveying a large number of isolates for genetic variation in a particular gene of interest.

Specific chromosomal translocations and therapy-related leukemia induced by bimolane therapy for psoriasis

This paper reports for the first time results of cytogenetic studies on 14 consecutive secondary acute non-lymphocytic leukemia (S-ANLL) induced by bimolane therapy. They included 10 males and 4 females with ages ranging from 17 to 54 years. They had all suffered from psoriasis and received bimolane treatment before the occurrence of their leukemia. The total dose of bimolane ranged from 40 to 400 g (mean dose 194 g). The interval between the initiation of bimolane therapy and the diagnosis of leukemia was 12-96 months (median 30 months). A preleukemic phase was only found in one case. No dysplastic features in the hemopoietic series were seen in any patient. Chromosome analysis of bone marrow cells using banding techniques revealed clonal karyotypic abnormalities in all cases: t(15;17) in 8 cases of M3, of which 75% had extra abnormalities, t(8;21) in 4 cases of M2, del(7q) only in one case of M4 and one case of M5. After antileukemic therapy, complete remission was obtained in 10 out of 12 cases with specific translocations and one out of 2 cases with 7q-anomaly, respectively. The former survived 4-58 months (median 12 months), while the latter 1 and 9 months, respectively. This study indicates that: (1) bimolane is a causative factor of leukemia in this series; (2) the leukemia in our series is therapy-related leukemia (TRL) rather than de novo ANLL; (3) there exists, in fact, a new subgroup of TRL characterized by specific rearrangements, whose clinical, hematological and prognostic features and pathogenetic mechanism may be different from classical TRL characterized by chromosome abnormalities involving absence or deletion of parts of chromosome 5 and/or 7.

Calcium antagonists in the treatment of experimental cerebral ischemia

Calcium ion functions widely as an intracellular messenger and regulator. Intracellular calcium dyshomeostasis occurs during hypoxic/ischemic cell injury, and pharmacological antagonism of calcium entry into neurons has been considered to be of potential therapeutic value. Calcium antagonists, in addition, tend to improve cerebral perfusion of both the normal and abnormal (post-ischemic) brain. Studies of these agents have shown variable degrees of cerebroprotection in focal and global ischemia models. (S)-Emopamil is a phenylalkylamine-type calcium channel blocker which also exhibits stereoselective antagonism of the serotonin S2 receptor and has excellent blood-brain barrier penetrability. Protection of hippocampal CA1 neurons has been demonstrated with pre-ischemic administration of (S)-emopamil in global ischemia models. Our laboratory has compared the efficacy of pre- vs. post-ischemic (S)-emopamil treatment on neuronal necrosis resulting from 10 min of transient normothermic global ischemia in the rat. (S)-Emopamil pre-treatment, 20 mg/kg i.p., 30 min prior to ischemia, with a second dose 2.5 h later, resulted in 1.8-2.4 fold increases in numbers of surviving CA1 pyramidal neurons. Post-ischemic administration was ineffective. Intracerebral microdialysis has revealed a partial attenuation of dopamine release with pre-ischemic (S)-emopamil administration. In focal cerebral ischemia (middle cerebral artery occlusion in the rat), our laboratory has demonstrated a marked reduction in cortical infarct volume with (S)-emopamil pre- or post-treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Digital replantation. A ten-year retrospective study

Eight hundred and two digits (592 complete amputation and 210 incomplete amputations) of 549 patients were replanted. The male to female ratio was 3:1 and the age range 1-63 years. 728 digits survived and 74 digits failed. The overall survival rate was 90.8%. Special varieties of complicated amputation were encountered in this series: (1) distal segment replantation, 139 digits, 131 digits (94%) survived; (2) digital replantation of children, 45 cases, 78 digits, average age 3.8 years, the youngest being 1 year old, 68 digits survived (88.7%); (3) rotational avulsion amputation of thumb, 26 digits, 23 digits (88.4%) survived; (4) bilateral digit amputation, 8 cases, 44 digits amputated, 38 digits replanted, including 9 digits of a ten-digit guillotined case. All the digits were salvaged. We conclude that thorough debridement, meticulous anastomosis of blood vessels and timely management of vascular crisis are keys to high survival rate, while judicious selection of indication, proper internal fixation of bone, anastomosis of as many blood vessels as possible, attentive repair of nerves and tendons, sound rehabilitation program are important measures in improving postoperative function.

The catalytic domain of the neurofibromatosis type 1 gene product stimulates ras GTPase and complements ira mutants of S. cerevisiae

Sequencing of the neurofibromatosis gene (NF1) revealed a striking similarity among NF1, yeast IRA proteins, and mammalian GAP (GTPase-activating protein). Using both genetic and biochemical assays, we demonstrate that this homology domain of the NF1 protein interacts with ras proteins. First, expression of this NF1 domain suppressed the heat shock-sensitive phenotype of yeast ira1 and ira2 mutants. Second, this NF1 domain, after purification as a glutathione S-transferase (GST) fusion protein, strongly stimulated the GTPase activity of yeast RAS2 and human H-ras proteins. The GST-NF1 protein, however, did not stimulate the GTPase activity of oncogenic mutant ras proteins, H-rasVal-12 and yeast RAS2Val-19 mutants, or a yeast RAS2 effector mutant. These results establish that this NF1 domain has ras GAP activity similar to that found with IRA2 protein and mammalian GAP, and therefore may also regulate ras function in vivo.

Hepadna virus nucleocapsid and surface antigens and the antigen-specific antibodies associated with hepatocyte plasma membranes in experimental woodchuck acute hepatitis

Hepatocyte plasma membranes purified from five woodchucks with distinct serologic and histologic patterns of experimentally induced acute woodchuck hepatitis virus (WHV) infection were studied to determine the virus antigens expression and anti-viral specificity of the bound immunoglobulins. WHV core, e, and surface antigens (WHcAg, WHeAg, and WHsAg, respectively) were analyzed with the use of immunoblotting technique both in the native form of these membranes and in the membranes treated with high molar urea or a nonionic detergent. The eluted material was tested either for the presence of WHV antigens or reactivity of the antibodies directed to the virus antigens. The data revealed that acute WHV infection is accompanied by hepatocyte plasma membrane expression of all three viral antigens tested. In all cases, native membranes displayed both WHeAg and WHsAg, whereas WHcAg presence was detected in hepatocyte plasma membranes after their disruption with urea or a detergent. The data indicated that a part or, in some instances, even the whole detectable WHcAg specificity can be incorporated into plasma membrane structure in such a way that it is not accessible for recognition by the specific antibodies (anti-WHc), suggesting at least a partial functional disability of this antigen as a target for immunologic reactions in in vivo conditions. In contrast, WHeAg specificity was detectable in all native membrane preparations studied and its expression was not evidently influenced by the employed treatments, whereas that of WHsAg tended to decline. Further, anti-WHc reactivity was identified in all membrane eluates tested, but antibodies to WHeAg (anti-WHe) were exclusively found in the material eluted from membranes originating from woodchucks with borderline histologic activity of acute hepatitis, which cleared away e antigen from the serum shortly before liver perfusion. Antibodies to WHsAg (anti-WHs) did not show up in the eluates. The present findings demonstrated that WHeAg specificity is not only exposed on the surface of infected hepatocytes, but is also relatively more easily accessible for serologic recognition than that of WHcAg in acute WHV infection. The above observation suggests that e antigen can serve as a potential plasma membrane target for hepatocytolytic attack in addition to that of WHsAg or WHcAg. Moreover, the results of this study demonstrated an apparent relationship between low histologic activity of liver inflammation, e antigen clearance from the circulation, and detectability of hepatocyte plasma membrane-bound anti-e antibodies in acute hepadna viral hepatitis.

[Effects of clonidine and norepinephrine on rabbit pulmonary artery strips with or without endothelium]

Relaxing responses of strips of rabbit pulmonary artery (RPA) with endothelium (+E) to norepinephrine (NE) during sustained contraction with KCl 20 mmol/L in the presence of propranolol (Pro) 10 mumol/L and prazosin (Pra) 1 mumol/L were more sensitive than those without endothelium (-E) to NE. These responses were inhibited by yohimbine (Yoh) 1 mumol/L. However, the relaxing responses of the strips to clonidine (Clo) were not different between RPA strips +E and -E in the presence of Pro+ Pra or Pro + Pra + Yoh 1 mumol/L. Relaxing responses of RPA strips -E precontracted by phenylephrine (PE) 1 mumol/L to Pra and Clo were greater than that of those precontracted by KCl 20 mmol/L. The relaxing responses of these strips precontracted by PE to Pra were larger than those precontracted by PE mumol/L; but that of those precontracted by PE and Clo to Yoh were not different. The results suggest that integrity of the endothelium is an important factor in the relaxing responses of RPA strips to NE. The relaxing effect of Clo on RPA strips precontracted by KCl 20 mmol/L may be due to alpha 1-adrenoceptor blockade on smooth muscle cells of the RPA strips.

Optimization of an HPLC peroxyoxalate chemiluminescence detection system for some dansyl amino acids

Bis(2,4,6-trichlorophenyl) oxalate (TCPO)-hydrogen-peroxide-generated chemiluminescence (CL) of four dansyl amino acids has been used as a model system for the optimization of a detection system in reversed-phase high-performance liquid chromatography. Dansylated alanine, glutamic acid, methionine, and norleucine were subjected to peroxyoxalate induced CL in a static system and in a flow system under various conditions with respect to TCPO (ethyl acetate) and hydrogen peroxide (acetone) concentrations, solvent composition and flow, using a two-pump or a one-pump post-column reagent system. From the CL-decay curve, the influence on the emission signal from the total flow rate in the detector was investigated. Special attention was focused on the mixing of the LC eluate and the reagent in order to combine an efficient collection of the emitted light using a 74 microliter flow cell (originally 10 microliters in the fluorescence detector) with minimal extra column band broadening. Therefore, a capillary fused-silica tubing of about 100 microns i.d. was inserted against the end-frit of the column and brought through a mixing tee, in which the solutions of TCPO and hydrogen peroxide were added. The column end tubing ended in the flow cell and the LC eluate and the reagents were mixed when entering the flow-cell. Average detection limits (S/N = 2) of 200 fmol injected dansylated amino acid could be reached. A comparison is made between the use of TCPO and DNPO (bis (2, 4-dinitrophenyl) oxalate).

Spontaneous regression of cardiac rhabdomyoma in tuberous sclerosis

Life-threatening cardiac rhabdomyoma in a newborn infant regressed spontaneously within a 5 month period. Since cardiac surgery for rhabdomyoma is dangerous in infancy, medical management should be considered if symptomatology is not severe. When a fetal arrhythmia is diagnosed, antenatal ultrasound examination for presence of cardiac tumors is warranted.

Activation of transforming potential of the human insulin receptor gene

A retrovirus containing part of the human insulin receptor (hIR) gene was constructed by replacing ros sequences in the avian sarcoma virus UR2 with hIR cDNA sequences coding for 46 amino acids of the extracellular domain and the entire transmembrane and cytoplasmic domains of the beta subunit of hIR. The resulting virus, named UIR, contains the hIR sequence fused to the 5' portion of the UR2 gag gene coding for p19. UIR is capable of transforming chicken embryo fibroblasts and promoting formation of colonies in soft agar; however, it does not form tumors in vivo. A variant that arose from the parental UIR is capable of efficiently inducing sarcomas in vivo. UIR-transformed cells exhibit higher rates of glucose uptake and growth than normal cells. The 4-kilobase UIR genome codes for a membrane-associated, glycosylated gag-hIR fusion protein of 75 kDa designated P75gag-hir. P75gag-hir contains a protein tyrosine kinase activity that is capable of undergoing autophosphorylation and of phosphorylating foreign substrates in vitro; it is phosphorylated at both serine and tyrosine residues in vivo.

Regulation of the expression of proto-oncogene c-src by alternative RNA splicing in chicken skeletal muscle

Expression of the c-src locus in skeletal muscle of the chicken was found to be different from other tissues. A 4 kilobases (kb) cellular src (c-src) mRNA, which most likely codes for pp60c-src, is expressed in various chicken tissues examined, and most of its approximately 2.2 kb non-coding sequences are present at the 3' end of the RNA molecule. Whereas the 4 kb RNA is also expressed in embryonic chicken muscle, it disappears shortly before hatching and is replaced by a smaller-sized class of c-src mRNAs of 2.8 to 3.3 kb. The transition of expression from the 4 kb to the 2.8-3.3 kb RNA in skeletal muscle occurs shortly before hatching of the chicken and persists into adulthood. The two classes of the c-src mRNA share sequences both within the 5' coding and the 3' non-coding regions of pp60c-src, however, the 2.8 to 3.3 kb RNA lacks most of the kinase domain, but it contains upstream c-src sequences missing in the 4 kb RNA. The two classes of c-src mRNA most likely are generated by alternative splicing, and the smaller c-src RNA most likely codes for a product other than tyrosine protein kinase.

Electronic imaging system for direct and rapid quantitation of fluorescence from electrophoretic gels: application to ethidium bromide-stained DNA

We have built an electronic imaging system based on a modified charge-coupled-device television camera that directly quantitates the distribution of fluorescence from electrophoretic gels, chromatograms, and other stationary sources. Exposure times can exceed 1 min. Unlike the photographic system that it replaces, the response of the camera is directly proportional to the intensity of incident fluorescence, and image data are digitized and stored in computer memory ready for analysis immediately upon completion of an exposure. We describe procedures for the display, normalization, and archival storage of image data and programs that use images of ethidium bromide-stained DNA in alkaline agarose gels to quantitate single-strand breaks in DNA.

Vacuum ultraviolet circular dichroism of keratan sulfate

The vacuum ultraviolet CD of keratan sulfate reveals an intense negative CD band at 171 nm. Its intensity can be rationalized with a recently proposed quadrant rule in terms of the acetamido group being slightly tilted toward the hexosaminidic linkage oxygen. The same structural feature accounts for the particularly intense negative n-pi CD band near 210 nm.

Regulation of deoxyadenosine and nucleoside analog phosphorylation by human placental adenosine kinase

The enzymes responsible for phosphorylation of adenosine and nucleoside analogs are important in the pathogenesis of adenosine deaminase deficiency and for the activation of specific anticancer and antiviral drugs. We examined the role of adenosine kinase in catalyzing these reactions using an enzyme purified 4000-fold (2.1 umol/min/mg) from human placenta. The Km values of adenosine and ATP are 135 uM and 4 uM, respectively. Adenosine kinase phosphorylates adenine arabinoside with an apparent Km value of 1 mM using adenosine kinase assay conditions. The Km values for 6-methylmercaptopurine riboside and 5-iodotubercidin, substrates for adenosine kinase, are estimated to be 4.5 uM and 2.6 nM, respectively. These data indicate that dadenosine phosphorylation by adenosine kinase is primarily regulated by its Km, and the concentrations of Mg2+, ADP and AMP. The high Km values for phosphorylation of dadenosine and adenine arabinoside suggest that adenosine kinase may be less likely to phosphorylate these nucleosides in vivo than other enzymes with lower Km values. Adenosine kinase appears to be important for adenosine analog phosphorylation where the Michaelis constant is in the low micromolar range.

Regulation of deoxyadenosine and nucleoside analog phosphorylation by human placental adenosine kinase

The enzymes responsible for the phosphorylation of deoxyadenosine and nucleoside analogs are important in the pathogenesis of adenosine deaminase deficiency and in the activation of specific anticancer and antiviral drugs. We examined the role of adenosine kinase in catalyzing these reactions using an enzyme purified 4000-fold (2.1 mumol/min/mg) from human placenta. The Km values of deoxyadenosine and ATP are 135 and 4 microM, respectively. Potassium and magnesium are absolute requirements for deoxyadenosine phosphorylation, and 150 mM potassium and 5 mM MgCl2 are critical for linear kinetics. With only 0.4 mM MgCl2 in excess of ATP levels, the Km for deoxyadenosine is increased 10-fold. ADP is a competitive inhibitor with a Ki of 13 microM with variable MgATP2-, while it is a mixed inhibitor with a Ki and Ki' of 600 and 92 microM, respectively, when deoxyadenosine is variable. AMP is a mixed inhibitor with Ki and Ki' of 177 and 15 microM, respectively, with variable deoxyadenosine; it is a non-competitive inhibitor with a Ki of 17 microM and Ki' of 27 microM with variable ATP. Adenosine kinase phosphorylates adenine arabinoside with an apparent Km of 1 mM using deoxyadenosine kinase assay conditions. The Km values for 6-methylmercaptopurine riboside and 5-iodotubercidin, substrates for adenosine kinase, are estimated to be 4.5 microM and 2.6 nM, respectively. Other nucleoside analogs are potent inhibitors of deoxyadenosine phosphorylation, but their status as substrates remains unknown. These data indicate that deoxyadenosine phosphorylation by adenosine kinase is primarily regulated by its Km and the concentrations of Mg2+, ADP, and AMP. The high Km values for phosphorylation of deoxyadenosine and adenine arabinoside suggest that adenosine kinase may be less likely to phosphorylate these nucleosides in vivo than other enzymes with lower Km values. Adenosine kinase appears to be important for adenosine analog phosphorylation where the Michaelis constant is in the low micromolar range.

Replantation of avulsively amputated thumb: a report of 15 cases

Since 1978 a series of 15 avulsively amputated thumbs were replanted with survival of the replantation in 14 patients. Good restoration of sensory and motor functions for these patients eradicates the old concept that replantation for avulsively amputated digits is contraindicated or a poor risk. We emphasize the importance of proper management of the transfer technique of the severed tendons, nerves, and blood vessels during the replantation. Details are described. The only failure was a result of technical faults. We conclude that replantation of an avulsively amputated thumb is worthwhile and will be beneficial to the patient.

Genetic analysis of staphylococcal nuclease: identification of three intragenic "global" suppressors of nuclease-minus mutations

A collection of 77 unique missense mutations distributed across the gene encoding staphylococcal nuclease (nuc) has been assembled. These mutations were induced by random gap misrepair mutagenesis of the cloned gene and were identified in E. coli transformants expressing reduced levels of nuclease activity. Four nuc- mutations which alter amino acid residues at positions outside of the active site region of the enzyme were submitted to a second round of mutagenesis, and characterization of several independent NUC+ isolates lead to the identification of three second-site suppressor mutations within the protein-coding sequence of the nuc gene. On separation from the mutation originally suppressed and recombination with a number of other nuc- mutations, all three suppressors displayed the property of "global" suppression, i.e., phenotypic suppression of the nuclease-minus character of multiple different alleles. A simple and generally applicable strategy was used to obtain efficient homologous recombination between plasmids for purposes of mapping nuc- mutations, mapping second-site suppressors and constructing double mutant combinations from pairs of single mutations.

Human helper T cell factor(s). IV. Demonstration of a human late-acting B cell differentiation factor acting on Staphylococcus aureus Cowan I-stimulated B cells

At least two distinct B cell stimulatory factors (BSF) were found to be involved in the differentiation of Staphylococcus aureus Cowan I (SAC)-stimulated human B cells to IgG-producing cells. A factor tentatively called B cell differentiation factor I (BCDF I) was found in one fraction, and a second factor, BCDF II was found in another fraction. The BCDF I fraction alone induces IgG-production in SAC-stimulated B cells, but the BCDF II fraction does not. The BCDF II fraction enhances IgG production in SAC-stimulated B cells in the presence of the BCDF I fraction. Studies concerning the time-course of the action of the BCDF II fraction revealed that it contains a late-acting differentiation factor that acts on B cells most effectively when it is added to the SAC-stimulated B cell culture after the addition of BCDF I fraction; it induces IgG plaque-forming cells within 1 day. The pI value of a late-acting BCDF was in the range of 5 to 6; this pI range is different from that of BCDF I but similar to that of BCDF II, which was shown in our previous studies to be able to induce IgG production in Epstein Barr Virus-transformed B lymphoblastoid cell lines. In addition, the m.w. of a late-acting BCDF were about 35,000 and 20,000, which are the same as those of BCDF II, and thus its identity with BCDF II was suggested.

Human helper T cell factor(s). IV. Demonstration of a human late-acting B cell differentiation factor acting on Staphylococcus aureus Cowan I-stimulated B cells

At least two distinct B cell stimulatory factors (BSF) were found to be involved in the differentiation of Staphylococcus aureus Cowan I (SAC)-stimulated human B cells to IgG-producing cells. A factor tentatively called B cell differentiation factor I (BCDF I) was found in one fraction, and a second factor, BCDF II was found in another fraction. The BCDF I fraction alone induces IgG-production in SAC-stimulated B cells, but the BCDF II fraction does not. The BCDF II fraction enhances IgG production in SAC-stimulated B cells in the presence of the BCDF I fraction. Studies concerning the time-course of the action of the BCDF II fraction revealed that it contains a late-acting differentiation factor that acts on B cells most effectively when it is added to the SAC-stimulated B cell culture after the addition of BCDF I fraction; it induces IgG plaque-forming cells within 1 day. The pI value of a late-acting BCDF was in the range of 5 to 6; this pI range is different from that of BCDF I but similar to that of BCDF II, which was shown in our previous studies to be able to induce IgG production in Epstein Barr Virus-transformed B lymphoblastoid cell lines. In addition, the m.w. of a late-acting BCDF were about 35,000 and 20,000, which are the same as those of BCDF II, and thus its identity with BCDF II was suggested.

A consideration of methods of insulin assay

The potency of “unknown” solutions of insulin has been determined by the U.S.P. rabbit method of assay. The same solutions have also been assayed by the mouse convulsion method, mouse hemidiaphragm method and by several immunoassay methods. The record shows reasonable agreement among the various methods which were used.