Functional changes in dorsal root ganglion cells after chronic nerve constriction in the rat

1. We studied the effects of a chronic nerve constriction on the evoked responses in dorsal root fibers in the rat to norepinephrine and to thermal stimuli applied either to the dorsal root ganglion (DRG) or the site of nerve injury. We recorded a total of 59 C fibers, 15 A delta-fibers, and 46 A beta-fibers from the L5 dorsal root of the rats 11-52 days after a loose ligation of the ipsilateral sciatic nerve. Most fibers were identified by the presence of spontaneous activity (SA) that originated partially at and/or proximal to the injury site. In addition, we recorded 20 C fibers, 1 A delta-fiber, and 28 A beta-fibers from the dorsal roots of normal, uninjured neurons. 2. In nerve-injured rats, the SA of some C fibers was generally increased by cooling and decreased by heating either site. In contrast, the SA of most A beta-fibers was increased by heating either the injury site or the DRG. Cooling the DRG decreased SA in A beta-fibers, whereas cooling the injury site typically had no effect. Excitatory responses were not evoked in any fiber group when the same thermal stimuli were applied to the nerve or DRG tested in normal, uninjured rats. 3. Norepinephrine (< 0.5 mM) applied either to the injury site or the DRG increased the SA of most C fibers and A delta-fibers but only a minority of A beta-fibers in previously injured nerves. The threshold concentration for excitation of the DRG somata of C fibers was 0.01 mM. No effects were found for fibers in uninjured nerves. 4. The effect of norepinephrine was blocked by a pretreatment with yohimbine, an alpha 2-blocker, but not with prazosin, an alpha 1-blocker. 5. Stimulation of the sympathetic trunk (L2-L3) excited most C fibers and a minority of A beta-fibers. In contrast, the SA of a minority of C fibers and A beta-fibers was depressed during sympathetic stimulation. 6. After a chronic nerve constriction the DRG becomes a source of abnormal activity modulated by sympathetically released norepinephrine acting on alpha 2 receptors in DRG somata. This neuropathic activity may contribute to cutaneous pain and hyperalgesia.

[The effects of 2-chloro-4-bromo-alpha-methylcinnamic acid on the neuromuscular transmission of toad]

The effects of 2-chloro-4-bromo-alpha-methylcinnamic acid sodium (SC1001 Na) on neuromuscular transmission were tested by means of intracellular recordings in isolated sciatic nerve-sartorius preparations of toad. The results were: (1) at a concentration of 0.1mmol/L, SC1001 Na had no effect on end-plate potential (EPP); at a concentration of 1 mmol/L, SC1001 Na reduced the amplitude of the EPP significantly, and the paired-pulse facilitation was also decreased; at a concentration of 10mmol/L, SC1001 Na blocked the EPP completely; (2) the 0.1 mmol/L and 1mmol/L groups of drug had no effect on the resting potential of the toad muscle fibers; the resting potential was reduced significantly by SC1001Na at the concentration of 10mmol/L, the action of 10mmol/L drug was irreversible. These results suggest that SC1001 Na may block the neuromuscular transmission of toad, and the blocking effect might be mainly due to a presynaptic mechanism.

[Urinary calcium excretion in patients with pregnant hypertension syndrome]

We observed the urinary calcium in 103 patients in the third trimester of pregnancy and the relation between the 24 hour calcium excretion and the calcium/creatinine ratio of a single void urine sample. The study population included 75 normal pregnant women and 28 pregnant woman with pregnant hypertension syndrome. The 24 hour urinary calcium excretion in the patients with pregnant hypertension syndrome was significantly lower (0.70 +/- 0.36 mmol/L) than that in normal pregnant women (4.00 +/- 1.90 mml/L) P < 0.0005. The 24 hour calcium excretion correlated well with the calcium to creatinine ratio of a single void morning urine sample in the two groups. We conclude that the urinary calcium excretion can be used as an indicator for pregnant hypertension syndrome. The 24 hour urinary calcium excretion can be estimated from a single void urine sample. Pregnant hypertension syndrome is associated with hypocalciuria, probably due to increased tubular reabsorption of calcium.

Nucleotide sequence of maize dwarf mosaic virus capsid protein gene and its expression in Escherichia coli

The 3'-terminal 1,279 nucleotide sequence of maize dwarf mosaic virus (MDMV) genome has been determined. This sequence contains an open reading frame of 1,023 nucleotides and a 3'-non-coding region of 256 nucleotides. The open reading frame includes all of the coding regions for the viral capsid protein (CP) and part of the viral nuclear inclusion protein (NIb). The predicted viral CP consists of 313 amino acid residues with a calculated molecular weight of 35,400. The amino acid sequence of the viral CP derived from MDMV cDNA shows about 47%-54% homology to that of 4 other potyviruses. The viral CP gene was constructed in frame with the lacZ gene in pUC19 plasmid and expressed in E. coli cells. The fusion polypeptide positively reacted in Western blot with an antiserum prepared against the native viral CP.

Sister-chromatid exchanges in lymphocytes from methimazole-induced hypothyroid mice

The inhibitory effect of an antithyroid drug on mouse T lymphocytes was investigated. Inbred C57BL/6 mice were provided with an antithyroid drug, methimazole, for 2, 4 and 6 weeks and the in vitro responses of the lymphocytes were studied. The proliferative responses of T lymphocytes from the spleen of methimazole (MMI)-treated mice significantly (p < 0.05) decreased following concanavalin A stimulation, and the inhibitory effect became prominent with the increased duration of MMI treatment. A concomitant increase in the frequency of induced sister-chromatid exchanges was also observed in these T lymphocytes. When the splenocytes were stimulated with concanavalin A for 24 h, their ability to produce interleukin-2 (IL-2) was significantly decreased (p < 0.05). The results indicated that methimazole interfered with the normal proliferation of T lymphocytes by suppressing the production of IL-2, a cytokine also known as T cell growth factor, as well as inducing a higher incidence of sister-chromatid exchange during cell division.

[Expression of chemically synthesized hybrid genes of Plasmodium falciparum and preliminary characterization of expressed products]

The chemically synthesized hybrid genes HGFC and HGFCAC were respectively recombinated with expression vector pWR450-1 and transferred into Escherichia coli. After adding IPTG to the cultural media, the bacteria harboring recombinant plasmid expressed the fusion proteins of exogenous gene products and partial amino acid of beta-galactosidase. The molecular weights of the two fusion proteins were 65 kDa and 77 kDa, respectively. The expressed fusion proteins could be recognized by antibodies of rabbit anti-RESA peptide EENVEHDA by Western blotting, indicating that the fusion proteins harbored the antigenic epitopes of Plasmodium falciparum.

Postnatal changes in size and actomyosin content of rabbit gastric myocytes

Maximal tension generated by gastric muscle is three to four times greater in weanlings than in newborn rabbits. To determine if this functional maturation is accompanied by structural changes, we compared length-tension relationships, myocyte number and size, and actomyosin content in muscle from the gastric body of newborn (1 day) and weanling (12 weeks) rabbits. Passive tension at optimal length (Lo) was six times greater in circular smooth muscle strips from weanling rabbits than from newborn rabbits. Active tension at Lo in weanling rabbits was three times greater than in newborn rabbits. For morphometry, muscle cross-sections stretched to Lo in the circular axis were photographed with electron microscopy (5300x). Cell number/unit area was counted in circular muscle layers from newborns and weanlings. Cross-sectional area of each cell was measured by computerized planimetry. There were 2.5 times more cells per unit area in newborn than in weanling tissue, P < 0.001. However, the mean cell area in newborns (5.4 +/- 4.6 microns2) was less than that in weanlings (13.5 +/- 11.7 microns2). Consequently, the muscle cells occupied similar total areas in newborns and weanlings. We measured actin and myosin heavy chain in full-thickness muscle homogenates using SDS gel electrophoresis and densitometric scanning. Actin and myosin concentrations were lower in newborns (9.6 +/- 1.3 micrograms g-1 wet weight and 5.6 +/- 0.7 micrograms g-1 wet wt, respectively) than in weanlings (17.7 +/- 3.0 micrograms g-1 wet wt and 8.2 +/- 1.6 micrograms g-1 wet wt respectively), each P < 0.01. The proportion of myosin heavy chain isozymes did not change with age. We conclude that there are postnatal increases in cell size and the quantity of actin and myosin in rabbit gastric muscle. The increase in quantity of contractile protein may be in part responsible for age-dependent increases in maximal tension.

[Effect of bee pollen on maternal nutrition and fetal growth]

Plant pollen collected by the honeybee is called bee pollen, which is a natural nutrient. We studied the effects of the bee pollen of Brassia campestres L. on maternal nutrition and fetal growth. Pregnant Sprague-Dawley rats at O-d were divided randomly into three groups. The control group (C) was fed with a diet. The other two groups (A) and (B) were fed with the diet plus bee pollen 20 g/kg.d-1 and 10 g/kg.d-1, respectively. All the dams in each group took a diet and drank water and libitm. Pollen-fed dams in both groups (A) and (B) had greater body weight and higher levels of haemoglobin, total protein, serum iron and albumin (P < 0.01, P < 0.05). Fetuses of pollen-fed dams had greater body weight (P < 0.01) and lower death rate (P < 0.005). No gross external, visceral and skeletal malformations were observed in the fetuses. These results suggested that bee pollen could improve maternal nutrition without affecting normal fetal development. It is a practical and effective nutrient during pregnancy.

A unique sodium-hydrogen exchange isoform (NHE-4) of the inner medulla of the rat kidney is induced by hyperosmolarity

Membrane sodium-hydrogen exchangers (NHEs), found in virtually all cell types, appear to have diverse and essential roles in regulating cellular pH and mediating vectorial transport by epithelial cells. However, the functional and physiological role of the recently cloned isoform NHE-4 remains unknown. Unlike other Na-H exchanger isoforms, NHE-4 transfected into NHE-deficient mutant fibroblasts demonstrated no amiloride-inhibitable sodium uptake, under basal or acid-loaded isoosmotic conditions. By immunoblot analysis, only the NHE-4 transfectants synthesized a 100-kDa protein, which cross-reacted to polyclonal antibody made to an NHE-4 fusion protein. However, when cells were subjected to acute hyperosmolar cell shrinkage conditions, amiloride-sensitive NHE activity was readily detected at 420 mosm, exhibiting maximal activity at 490 mosm. By in situ hybridization, NHE-4 expression in the rat kidney was found to be limited to the inner renal medullary collecting tubules, the region of highest tissue osmolarity fluctuations in the body. We conclude that NHE-4 is an unusual isoform of sodium-hydrogen exchangers that may play a specialized supplementary role in cell volume regulation.

[Clinical significance of immunohistochemistry and ultrastructural change of myocardium in viral myocarditis]

Endomyocardial biopsy (EMB) specimens from 56 patients with suspected viral myocarditis (VMT) were studied. With microscopical study of the EMB specimens stained with HE, 14 of the 56 cases were diagnosed as myocarditis (25%) and 24 as non-myocarditis (43%). But immunohistochemistry stain showed that the contents of myosin, actin and myoglobin reduced in 51 patients (91%). Ten of 56 specimens were observed under electron microscope (EM). EM examination revealed focal or diffuse lysis of myofibrils in 10 patients. The results showed that: (1) The myofibrils in VMT showed severe damage. (2) Immunohistochemistry and EM examination can be used as a supplement to the Dallas diagnosis standard in order to improve accuracy of EMB in diagnosing VMT.

Nuclear localization of p185neu tyrosine kinase and its association with transcriptional transactivation

The rat neu protooncogene encodes a 185 kD transmembrane protein (p185neu), which is a member of the epidermal growth factor receptor (EGFr) family. In searching for the signaling transducer of p185neu by using a two-hybrid selection system, we found, surprisingly, that the cytoplasmic domain of p185neu, when fused to the DNA-binding domain of GAL4 (amino acids 1-147), functioned as a transcriptional activator. We subsequently observed nuclear localization of p185neu. Interestingly, nuclear p185neu has a much higher extent of tyrosine phosphorylation than its nonnuclear counterpart. Our results suggest that a transmembrane receptor tyrosine kinase may enter the nucleus and be involved in transcriptional activation. This novel finding unveils a clue in the understanding of the mechanism of receptor tyrosine kinase-mediated signal transduction.

Glucocorticoids regulate Na+/H+ exchange expression and activity in region- and tissue-specific manner

Na+/H+ exchangers (NHEs) are integral membrane proteins that exchange Na+ for H+ across membranes. Four isoforms have been cloned (NHE-1-4). NHE-3 localizes to the apical domain, and its expression is increased in dexamethasone-treated rats by Northern analysis. This stimulatory effect on expression is region and tissue specific, being present in ileum and proximal colon, but not in jejunum, distal colon, or kidney. The increase in transcript expression in ileum correlates with an increase in protein expression by immunoblotting. Changes in apical Na+/H+ exchange activity, as measured by 22Na uptake into brush-border membrane vesicles, correlate with expression differences, with significant increases observed in ileum and proximal colon. In situ hybridization showed NHE-3 mRNA only in villus and absorptive cells of control rats, the pattern not being altered by dexamethasone treatment. This suggests that dexamethasone does not increase expression by inducing crypt cells to express NHE-3 prematurely. We conclude that glucocorticoids selectively increase intestinal NHE-3 activity in a region-specific manner and that this effect also appears to be tissue specific.

Cell-extracellular matrix interactions can regulate the switch between growth and differentiation in rat hepatocytes: reciprocal expression of C/EBP alpha and immediate-early growth response transcription factors

Previous investigations have shown that culture of freshly isolated hepatocytes under conventional conditions, i.e., on dried rat tail collagen in the presence of growth factors, facilitates cell growth but also causes an extensive down-regulation of most liver-specific functions. This dedifferentiation process can be prevented if the cells are cultured on a reconstituted basement membrane gel matrix derived from the Englebreth-Holm-Swarm mouse sarcoma tumor (EHS gel). To gain insight into the mechanisms regulating this response to extracellular matrix, we are analyzing the activities of two families of transcription factors, C/EBP and AP-1, which control the transcription of hepatic and growth-responsive genes, respectively. We demonstrate that isolation of hepatocytes from the normal quiescent rat liver by collagenase perfusion activates the immediate-early growth response program, as indicated by increased expression of c-jun, junB, c-fos, and c-myc mRNAs. Adhesion of these activated cells to dried rat tail collagen augments the elevated levels of these mRNAs for the initial 1 to 2 h postplating; junB and c-myc mRNA levels then drop steeply, with junB returning to normal quiescence and the c-myc level remaining slightly elevated during the 3-day culture period. Levels of c-jun mRNA and AP-1 DNA binding activity, however, remain elevated from the outset, while C/EBP alpha mRNA expression is down-regulated, resulting in a decrease in the steady-state levels of the 42- and 30-kDa C/EBP alpha polypeptides and C/EBP alpha DNA binding activity. In contrast, C/EBP beta mRNA production remains at near-normal hepatic levels for 5 to 8 days of culture, although its DNA binding activity decreases severalfold during this time. Adhesion of hepatocytes to the EHS gel for the same period of time dramatically alters this program: it arrests growth and inhibits AP-1 DNA binding activity and the expression of c-jun, junB, and c-myc mRNAs, but, in addition, it restores C/EBP alpha mRNA and protein as well as C/EBP alpha and C/EBP beta DNA binding activities to the abundant levels present in freshly isolated hepatocytes. These changes are not due merely to growth inhibition, because suppression of hepatocyte proliferation on collagen by epidermal growth factor starvation or addition of transforming growth factor beta does not inhibit AP-1 activity or restore C/EBP alpha DNA binding activity to normal hepatic levels. These data suggest that expression of the normal hepatic phenotype requires that hepatocytes exist in a G0 state of growth arrest, facilitated here by adhesion of cells to the EHS gel, in order to express high levels of hepatic transcription factors such as C/EBP alpha.

[Clinical features and prognosis of paroxysmal atrial fibrillation in the elderly]

Eighty one elderly patients with paroxysmal atrial fibrillation were studied with respect to clinical features, effect of antiarrhythmic drugs and prognosis. 35 (43.2%) patients were associated with coronary artery disease and/or hypertension, while 23 (28.4%) patients had no other cardiovascular diseases. The latter condition was significantly less in patients over 60 years old when they had the first paroxysmal attack. Atrial fibrillation became permanent in 18 (22.2%) patients. Left atrial enlargement and abnormal cardiac function were significant independent factors affecting the type of atrial fibrillation. During an observation period of 12-84 months, the incidence of cerebral embolism and cardiac death were 6.1% and 4.9% respectively in all cases. We did not find that the prognosis of patients was affected by the types of atrial fibrillation.

Effects of the sodium channel blocker tetrodotoxin (TTX) on cellular ion homeostasis in rat brain subjected to complete ischemia

Anoxic depolarization (AD) and failure of the cellular ion homeostasis are suggested to play a key role in ischemia-induced neuronal death. Recent studies show that the blockade of Na+ influx significantly improved the neuronal outcome. In the present study, we investigated the effects of 10 microM tetrodotoxin (TTX) on ischemia-induced disturbances of ion homeostasis in the isolated perfused rat brain. TTX inhibited the spontaneous EEG activity, delayed the ischemia-induced tissue acidification, and significantly postponed the occurrence of AD by 65%. The [Ca2+]e elevation prior to AD was attenuated from 17.8% to 6% while the increase of the [Na+]e in this period was enhanced (from 2.9% to 7.3%). These findings implied that the ischemia-induced early cellular sodium load and the corresponding shrinkage of the extracellular space was counteracted by TTX. Our results suggest that the Na+ influx via voltage-dependent channels preceding complete breakdown of ion homeostasis is one major factor leading to cell depolarization. The massive Na+ influx coinciding with AD, however, may be mainly via non-selective cation channels or/and receptor-operated channels. Persistent Na+ influx deteriorates neuronal tissue integrity by favouring Ca2+ influx and edema formation. Blockade of ischemia-induced excessive Na+ influx is, therefore, a promising pharmacological approach for stroke treatment.

[Study on red blood cell immune adherence function in coriaria lactone-induced epileptic seizure rats]

The immune adherence function of red blood cells in 17 rats was studied. It was found that the rosette rate of red blood cell C3b receptor (RBC-C3bRR) was 7.45 +/- 1.36% in the epilepsy group (8 rats), and 10.84 +/- 1.77% in the control group (9 rats); and that the rosette rate of red blood cell immune complex (RBC-ICR) was 7.42 +/- 2.62% in the epilepsy, and 10.80 +/- 1.72% in the control. As compared with the control group, the rosette rate of red blood cell C3b receptor was remarkably decreased in the epilepsy group (P < 0.05). There was no significant difference between the two groups in RBC-ICR. The results from this study demonstrated that the CL-induced seizures might result in decrease in red blood cell immune adherence function of the epilepsy rats.

[Correlationship between cellular DNA and AgNOR protein content in the developing course of colorectal adenocarcinoma]

Cellular DNA and AgNOR protein content were evaluated by automatic image analysis in tissue sections stained by combined Feulgen-AgNOR method of 9 normal colonic mucosae, 45 colorectal adenomas and 27 colorectal correlation between AgNOR protein and DNA contents. In adenocarcinomas, the DNA and AgNOR protein contents were higher than those in adenomas, which were in turn higher than those in normal colonic mucosa. However, there was considerable overlapping in the DNA or AgNOR protein content between adenoma and adenocarcinoma groups and between adenoma and normal colonic mucosa groups. By assessing the correlationship between the DNA and AgNOR protein contents, the number of the overlapping cases was reduced significantly. Therefore it is much more reliable to distinguish colorectal adenomas from adenocarcinomas by using the correlationship between the cellular DNA and the AgNOR protein contents in the same specimens.

[Kaschin-Beck's disease in children's wrists: radiographic findings]

Based on the analysis of hand radiographs in 208 children with Kaschin-Beck's disease, the author's chief conclusions are as follow: The more severe Kaschin-Beck's is, the more opportunity the carpals have to be involved. Generally speaking, the capitatum and hamatum are frequently involved if the disease involves the carpals.

Chimeric evolution of the 2-microns genome in Saccharomyces cerevisiae

We compared the nucleotide substitution pattern over the entire genome of two unique variants of the 6,300-bp selfish DNA (2 microns) plasmid in Saccharomyces cerevisiae. The DNA sequence of the left-unique region is identical among 2-microns variants, while the right-unique region shows substantial divergence. This chimeric pattern cannot be explained by neutral or Darwinian selection models. We propose that horizontal transmission of the 2-microns plasmid coupled with a directed, polarized gene conversion maintains the DNA sequence of the left-unique region, whereas the right-unique region is subject to random drift and Darwinian selection.

Esophageal Crohn's disease--a case report

A case of esophageal Crohn's disease in a 52-year-old man is described. The patient was treated successfully by surgical excision of the esophagus. Because esophageal Crohn's disease is uncommon, we would like to discuss its clinical characteristics and to review the literature.

Detection of opiate-enhanced increases in DNA damage, HPRT mutants, and the mutation frequency in human HUT-78 cells

In previous studies we have shown highly significant increases in chromosome damage and sister chromatid exchanges in heroin addicts, particularly when caffeine and metabolic inhibitors are added to the medium. Using human HUT-78 T-cell cultures, we now find direct in vitro evidence of opiate-induced or opiate-promoted mutagenesis via several assay systems. First, with microgel electrophoresis (MGE), we observed graded, dose-dependent, significant increases (P < .0001) in the frequency of comet tails of fragmented DNA when cells were treated with morphine alone (5 x 10(-9) M up to 10(-7) M) or when co-treated with the more potent mutagen, ethylmethanesulfonate (EMS). There were also dose-dependent increases in the lengths and densities of the comet tails observed. These findings were confirmed by a series of MGE experiments in which several days of morphine exposure preceded a 2-hr pulse of EMS. Second, mutant frequency (MF) assays also indicated significant opiate effects. These studies required separate assessment of cloning efficiencies and the frequencies of TG-resistant, HPRT-deficient mutant clones under four test conditions: no treatment, morphine alone for 4 days, morphine plus EMS, and EMS alone. Prior to the treatment phase, aminopterin was used to eliminate background HPRT mutations. The medium was changed after the treatment phase, the cells were allowed to express mutant phenotypes, and then TG was added and resistant mutant clones counted after 16 days. The background MF level for controls and for cells treated with EMS alone were negligible at 5.12 x 10(-8) and 7.25 x 10(-8), respectively. In the cells treated with morphine alone or morphine plus EMS, MF levels increased very significantly (P < .001) by > 100-fold to 5.1 x 10(-6) and 7.0 x 10(-6), respectively. Cloning efficiency also decreased significantly with both morphine-exposed conditions. Preliminary analysis with the single strand conformational polymorphism (SSCP) procedure following 6-thioguanine (TG) selection, also confirmed the occurrence of Exon 3 mutants of the HPRT gene in cells exposed to morphine plus EMS. It appears that brief EMS exposure can be repaired, whereas, if morphine exposure persists through one or more cell cycles, direct or indirect mutagenesis is initiated.

Na+/H+ exchangers, NHE-1 and NHE-3, of rat intestine. Expression and localization

Na-H exchange (NHE) is one of the major non-nutritive Na absorptive pathways of the intestine and kidney. Of the four NHE isoforms that have been cloned, only one, NHE-3, appears to be epithelial specific. We have examined the regional and cellular expression of NHE-3 in the rat intestine. NHE-3 message in the small intestine was more abundant in the villus fractions of the small intestine than in the crypts. Analysis of NHE-3 mRNA distribution in the gut by in situ hybridization demonstrated epithelial cell specificity, as well as expression preferential to villus cells. NHE-1 message, in contrast, was ubiquitous, with slightly greater expression exhibited in the differentiating crypt and lower villus cells of the small intestine. Isoform-specific NHE-3 fusion protein antibody identified a 97-kD membrane protein in the upper villus cells of the small intestine, which was exclusively localized in the apical membrane. In contrast, antibody previously developed against the COOH-terminal region of human NHE-1 (McSwine, R. L., G. Babnigg, M. W. Musch, E. B. Chang, and M. L. Villereal, manuscript submitted for publication) identified a 110-kD basolateral membrane protein. These data suggest that unlike NHE-1, which probably serves a "housekeeping" function, NHE-3 may be involved in vectorial Na transport by the intestine.

The microfocus assay system (mfas) - a simple quantitative assay to identify inhibitory drugs targeted against specific oncogenes

We have developed an assay, the microfocus assay system (MFAS), that enables the quantitative assessment of anticancer drugs and their ability to specifically target and inhibit cellular oncogenes. Analysis of three chemotherapeutic reagents showed a differential negative effect against the ability of transformed cells containing either the oncogenic rat neu, human H-ras, or v-mos oncogene to form transformed foci on a background of normal fibroblasts. Though these drugs have not been examined previously for targeting against specific oncogenes, our results with the MFAS indicate preferential inhibitory effects against cells transformed with different oncogenes. Therefore, the MFAS should enable the large scale screening of anti-cancer drugs specifically targeted against known oncogenes and provide a quantitative measurement of their effectiveness.

Observation of therapeutic effect in 50 cases of chronic renal failure treated with rhubarb and adjuvant drugs

Treatment of chronic renal failure with rhubarb and adjuvant drugs combined with other appropriate measures alleviates the suffering of the patients and improves the quality of their survival. Most patients can take care of themselves after treatment, and some can engage in half-day work. The treatment prolongs the life of the patient, and reduces medical expenses. It is of definite social and economic benefit, and conforms with China's conditions. Except for very severe cases whose blood creatinine exceeds 884 mumol/L, it can be given to all patients. It can also be used as a transitional measure before more radical therapies may be instituted.

Differential transcription and translation of immediate early genes in the gerbil hippocampus after transient global ischemia

Excitotoxic activation of glutamate receptors is thought to be a key event for the molecular pathogenesis of postischemic delayed neuronal death of CA-1 neurons in the gerbil hippocampus. Glutamate receptor stimulation also causes induction of transcription factors that belong to the class of immediate early genes. We examined the expression of six different immediate early genes in the gerbil hippocampus after transient global ischemia. Comparative analysis of c-fos and Krox-24 expression was carried out in the same animals at the transcriptional and translational level by in situ hybridization and immunocytochemistry. Postischemic synthesis of four additional immediate early gene (IEG)-encoded proteins (FOS-B, c-JUN, JUN-B, and JUN-D) was investigated by immunocytochemistry at recirculation intervals between 1 and 48 h. After 5 min of ischemia, transcription of c-fos and Krox-24 mRNA was induced in all hippocampal subpopulations with peak expression at 1 h after recirculation. In vulnerable CA-1 neurons, increased transcription of c-fos and Krox-24 was not followed by translation into protein. Induction of immediate early gene-encoded proteins was restricted to neuronal populations less vulnerable to brief ischemia and identified neurons that are targets of glutamate receptor-mediated neurotoxicity but that are destined to survive. Our data indicate an asynchronous synthesis and persistence of individual IEG-encoded proteins in these neurons. The staggered induction implies that combinatorial changes of transcription factors allow a differential postischemic regulation of target gene expression both spatially and over time.

Identification and characterization of a factor which is essential for assembly of transcarboxylase

Transcarboxylase (TC) from Propionibacterium shermanii is a biotin-containing enzyme which catalyzes the reversible transfer of a carboxyl group from methylmalonyl-CoA to pyruvate. It is composed of a central, hexameric 12S subunit with six outer, dimeric 5S subunits held in a stable 26S complex by twelve 1.3S biotinyl subunits. Each of these subunits has been cloned from the P. shermanii genome and expressed in Escherichia coli. The purified, expressed recombinant proteins are all indistinguishable from their authentic counterparts except for the recombinant 5S subunit (termed 5S WT), which does not form TC complexes or catalyze the overall transcarboxylase reaction. Circular dichroism and isoelectric focusing suggested differences existed between the authentic and E. coli-expressed 5S proteins. HPLC gel filtration was used to separate the authentic 5S dimer from additional components in the preparation. 5S dimer thus purified was unable to form TC complexes or catalyze the overall reaction, behaving identically to the recombinant 5S WT subunit. Fractions from the HPLC gel-filtration purification of authentic 5S were then added to 5S WT or 5S dimer, and one fraction was identified which catalyzed the assembly of TC complexes with either 5S preparation. This assembly activity was shown to be dependent on the concentration of this HPLC fraction. Assembly-promoting factor (APF) is heat-stable and probably a protein, on the basis of its protease susceptibility. Studies with APF and the other TC subunits demonstrate its ability to promote complex formation with 12S and 1.3S subunits. Since the APF was purified from crystals of 26S TC, we believe it to be a novel, previously unidentified subunit of transcarboxylase.

Purification and characterization of the recombinant 5 S subunit of transcarboxylase from Escherichia coli

Transcarboxylase from Propionibacterium shermanii is a biotin-containing enzyme which catalyzes the reversible transfer of a carboxyl group from methylmalonyl-CoA to pyruvate. It is composed of a central, hexameric 12 S subunit, 6 outer dimeric 5 S subunits which are held in a complex by 12 1.3 S biotinyl subunits. The transcarboxylase reaction requires two partial reactions, one of which is specific to 5 S. The cloning and expression of each of these subunits in Escherichia coli have been reported. We have designed a method for the purification of the 5 S subunit from an E. coli expression system. Protein purified to homogeneity by this method was shown to be active in the 5 S partial reaction, but unable to catalyze the overall transcarboxylase reaction. This protein was characterized as to its ability to form stable dimers, associate with the 1.3 S subunit in stable complexes referred to as 6 S, and assemble whole TC. The latter activity was shown to be lacking. The purified protein has a native molecular weight of 120 kDa and a subunit molecular weight of 60 kDa, consistent with the 5 S dimer. Plasma emission analysis of the metal content of the recombinant protein demonstrated the presence of both Co and Zn, comparable to the authentic protein. Fluorescence analysis verified the ability of the purified protein to bind substrates and 1.3 S subunits appropriately. Sequencing of the amino terminus and determination of the amino acid composition of the recombinant protein relative to that of the authentic subunit further verified the identity of the purified protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium nitroprusside stimulates anion secretion and inhibits sodium chloride absorption in rat colon

The effects of sodium nitroprusside (SNP) on intestinal electrolyte transport were studied in rat colon mounted in Ussing chambers. Serosal addition of SNP increases short-circuit current (Isc) in a concentration-dependent manner. The maximal change in Isc was 35.6 +/- 2.3 microA/cm2 at 1 mM SNP (ED50 approximately 81 microM). S-nitroso-N-acetylpenicillamine, a nitrosothiol which can release nitric oxide, also stimulated an increase in Isc of 13.9 +/- 3.1 microA/cm2 at a concentration of 100 microM. The response to SNP was rapid, peaking at about 4 min with partial return to baseline at 20 to 30 min. Isc responses to SNP were significantly less in the cecum and ileum as well as after mucosal addition in the distal colon. Pretreatment with serosal atropine, cimetidine, pyrilamine, ketanserin, and N omega-nitro-L-arginine and mucosal amiloride did not inhibit the SNP-stimulated Isc; iodine, methylene blue, bumetanide, piroxicam, and tetrodotoxin each significantly decreased the response and piroxicam plus tetrodotoxin abolished it. Transmural 22Na+ and 36Cl- flux studies demonstrated that the change in Isc produced by SNP was attributable to anion secretion. SNP also inhibited neutral Na+ and Cl- absorption, with the inhibition of Na+, but not Cl- absorption eliminated by tetrodotoxin and piroxicam pretreatment. In summary, SNP has several effects on intestinal electrolyte transport, suggesting that nitric oxide or other components of nitrovasodilators may be important physiological mediators of salt and water transport and may play a role in stimulated colonic epithelial electrolyte transport in inflamed tissues.

Light-regulated and cell-specific expression of tomato rbcS-gusA and rice rbcS-gusA fusion genes in transgenic rice

A previously isolated rice (Oryza sativa) rbcS gene was further characterized. This analysis revealed specific sequences in the 5' regulatory region of the rice rbcS gene that are conserved in rbcS genes of other monocotyledonous species. In transgenic rice plants, we examined the expression of the beta-glucuronidase (gusA) reporter gene directed by the 2.8-kb promoter region of the rice rbcS gene. To examine differences in the regulation of monocotyledonous and dicotyledonous rbcS promoters, the activity of a tomato rbcS promoter was also investigated in transgenic rice plants. Our results indicated that both rice and tomato rbcS promoters confer mesophyll-specific expression of the gusA reporter gene in transgenic rice plants and that this expression is induced by light. However, the expression level of the rice rbcS-gusA gene was higher than that of the tomato rbcS-gusA gene, suggesting the presence of quantitative differences in the activity of these particular monocotyledonous and dicotyledonous rbcS promoters in transgenic rice. Histochemical analysis of rbcS-gusA gene expression showed that the observed light induction was only found in mesophyll cells. Furthermore, it was demonstrated that the light regulation of rice rbcS-gusA gene expression was primarily at the level of mRNA accumulation. We show that the rice rbcS gene promoter should be useful for expression of agronomically important genes for genetic engineering of monocotyledonous species.

The resistance of macrophage-like tumour cell lines to growth inhibition by lipopolysaccharide and pertussis toxin

The process of tumorigenesis is frequently associated with resistance to growth inhibition by physiological regulators of normal cells. Murine macrophage-like cell lines BAC1.2F5, RAW264, J774.1A and PU5/1.8 were resistant to growth inhibition by bacterial lipopolysaccharide (LPS) and pertussis toxin, agents that blocked growth of primary bone marrow-derived macrophages (BMDM) in the presence of macrophage colony-stimulating factor (CSF-1). The resistance of the CSF-1-dependent cell line BAC1.2F5 to growth inhibition by pertussis toxin argues against the possibility that pertussis toxin-sensitive G proteins are essential for the pathway of growth stimulation by CSF-1. Conversely, these data add further weight to the argument that LPS mediates some of its biological activities by mimicking the action of pertussis toxin and inhibiting G protein function. The resistance of cell lines to LPS and pertussis toxin was not correlated with any alteration in the expression of mRNA encoding any of three pertussis-toxin sensitive G protein alpha subunits. The pattern of G protein expression was consistent between primary cells and tumour cells, suggesting that this is a differentiation marker. In particular, Gi alpha 2 mRNA was expressed at remarkably high levels in all of the cells. The specificity of LPS resistance was investigated by studying down-regulation of CSF-1 binding and induction of protooncogene c-fos and tumour necrosis factor (TNF) mRNA. BAC1.2F5 cells were LPS-resistant in each of these assays. In CSF-1 binding, RAW264 and J774.1A responded in the same way as bone marrow-derived macrophages but required higher doses of LPS, whereas c-fos and TNF mRNA were induced in these cells at concentrations that did not inhibit growth. In PU5/1.8 cells, CSF-1 binding was already very low and was not further down-regulated, but c-fos and TNF mRNA was inducible by LPS. By contrast to primary macrophages, the cell lines did not respond to LPS with down-regulation of c-fms mRNA, which encodes the CSF-1 receptor. Hence, the resistance of macrophage-like tumour cells to LPS and pertussis toxin was specific to the pathways controlling growth, and was correlated with altered regulation of the CSF-1 receptor.

Isoglobotetraosylceramide is a marker for highly metastatic cells in rat mammary adenocarcinomas

We have previously identified a neutral glycolipid antigen which appears to be a surface antigenic marker for the metastatic subpopulation in the R3230AC rat mammary adenocarcinoma (S.A. Carlsen, M. Barry, and K. Newton, Clin. Exp. Metastasis, 8: 141-151, 1990). In this article we describe the structural characterization of this glycolipid antigen. The sequence of the sugars in the saccharide portion of the molecule was determined by specific glycosidase cleavage and further confirmed by mass spectroscopic analysis. The nature of the linkages between the monosaccharide units was determined by methylation analysis. The final structure was confirmed by NMR analysis and found to be isoglobotetraosylceramide (GalNAc beta 1-3Gal alpha 1-3Gal beta 1-4Gle beta 1-O-ceramide). We also present evidence that the cells marked by this antigen have a higher metastatic potential than the cells lacking this glycolipid as measured by the formation of lung colonies after i.v. injection of the cells into the tail vein of the rat. Furthermore, isoglobotetraosylceramide seems to play a direct role in the metastatic process since the blocking of exposed antigen with monoclonal antibodies, or their Fab fragments, results in a highly significant decrease in lung colony formation.

Molecular cloning and adhesive properties of murine platelet/endothelial cell adhesion molecule 1

We describe the isolation and characterization of a functional murine platelet/endothelial cell adhesion molecule (PECAM) 1 cDNA clone from a mouse lung library. At the nucleotide level, the coding sequence of murine PECAM-1 is 73% identical to human PECAM-1, and at the amino acid level, the sequence is 79% homologous to its human counterpart. Southern hybridization reveals that one copy of the gene exists in the mouse genome; Northern hybridization reveals a single mRNA species in mouse lung tissue. COS-7 and mouse L cells transfected with murine PECAM-1 expressed a 130-kDa glycoprotein on their surfaces that reacted with anti-murine PECAM-1 monoclonal antibody and comigrated on SDS/PAGE with human PECAM-1. Stable L-cell transfectants aggregate with each other in a PECAM-dependent, homophilic manner.

Nereistoxin: a naturally occurring toxin with redox effects on neuronal nicotinic acetylcholine receptors in chick retina

Nereistoxin (NTX; 4-N,N-dimethylamino-1,2-dithiolane) is previously reported to block both muscle and neuronal nicotinic acetylcholine receptors, and reversibly inhibit radioligand binding to Torpedo nicotinic receptors. Here, we studied redox effects of NTX on neuronal nicotinic receptors in chick retinas by electrophysiological recordings and by [125I]neuronal bungarotoxin binding. NTX blocked retinal responses to the nicotinic agonist dimethylphenylpiperazinium (300 microM, 2 sec) with an IC50 of 3.5 microM. NTX inhibition was selective for nicotinic receptors, long lasting and not reversible upon washing. The nonselective oxidizing compound dithiobis(nitrobenzoic acid) (1 mM) transiently and repetitively reversed NTX (100 microM) inhibition (85% recovery). After application of the alkylating agent bromoacetylcholine (2 or 100 microM, with 2 microM neostigmine), dithiobis(nitrobenzoic acid) could no longer restore nicotinic function. d-Tubocurarine (300 microM) equally protected against alkylation with bromoacetylcholine (2 microM) after dithiothreitol (2 mM) or NTX treatment. The action of NTX differs from that of dithiothreitol because the agonist dimethylphenylpiperazinium (30 microM) protects against inactivation by dithiothreitol, but not by NTX. NTX reversibly inhibited [125I]neuronal bungarotoxin binding to chick retinal homogenates (IC50 = 16 microM). The present study suggests that nereistoxin or a metabolite is a potent antagonist as well as a selective reducing agent for nicotinic receptors in chick retina. As a dithiolane, this latter action by nereistoxin remains to be explained.

The indirect pathway of hepatic glycogen synthesis and reduction of food intake by metabolic inhibitors

The increasingly recognized role of the indirect pathway (glycolysis followed by hepatic gluconeogenesis) for glucose utilization and glycogen synthesis by the liver led us to administer 3-mercaptopicolinate (3MP), an inhibitor of phosphoenolpyruvate-carboxykinase, in an attempt to assess the role of liver glycogen or hexose-phosphates in the food-intake reducing effects of (-)hydroxy-citrate. Administration of (-)hydroxy-citrate increased hepatic glycogen content in i.v. glucose refed rats. Using the glucuronide probe technique, the mechanism of increased glycogen deposition was shown to be prolongation of indirect pathway (recycled) input. Daily (-)hydroxy-citrate significantly reduced food intake (from 12.0 +/- 2.3 to 6.4 +/- 3.6 g/day, p < 0.05) and had no chronic effect on hepatic glycogen content in rats trained to a single daily meal (meal-fed). Administration of 3MP completely suppressed hepatic glycogen synthesis (< 0.5 mg/g) when given alone or with (-)hydroxy-citrate. Isotopic studies confirmed inhibition of the indirect pathway of UDP-glucose synthesis. 3MP accentuated rather than prevented the (-)hydroxy-citrate reduction in food intake in meal-fed rats (intake 2.7 +/- 2.4 g/day). When given alone, 3MP also reduced intake (6.1 +/- 3.6 g/day). Severe hypoglycemia was observed (glucose < 20 mg/dl) in several meal-fed rats given repeated daily doses of 3MP, yet food intake did not occur despite food availability. Neither 3MP nor (-)hydroxy-citrate had any effects when given after the daily meal. We conclude that the role of the indirect glycogen synthesis pathway must be considered in any theory of regulation of food intake by hepatic metabolites and that, if the effects of these metabolic inhibitors can be shown not to be toxic or non-specific, neither hepatic glycogen nor hexose-phosphates are involved in the food-intake suppressive effects of (-)hydroxycitrate.

Age patterns of marital fertility: revising the Coale-Trussell method

"This article revises the Coale-Trussell method for analyzing data from the World Fertility Survey by proposing and testing alternative log-linear and log-multiplicative models. The models, in one form or another, represent the structural constraint underlying the Coale-Trussell method on the variation in the age pattern of human fertility. With a Poisson distribution assumption for the number of births, several parameters of the models are simultaneously estimated via maximum likelihood. It is shown that the new approach can be adopted whenever fertility limitation is compared across multiple populations or subpopulations."