The influence of surface properties on uptake of oil into complex coacervate microcapsules

A range of surfactants with different hydrophile-lipophile balance (HLB) values was selected to investigate the influence of interfacial properties on the uptake of oil droplets into complex coacervate microcapsules. The well characterized gelatin/acacia complex coacervate system was used in this study and the encapsulation of squalane, and oleic acid was investigated. The surfactants investigated were Span 85, Span 80, Span 40, egg yolk lecithin, and Tween 80. Combinations of surfactants were utilized to obtain intermediate HLB values. The percentage oil encapsulated was determined gravimetrically, based on the initial concentration and the amount extracted from the microcapsules. The aqueous interfacial tension values of the oils and oil/surfactant systems were measured using the Wilhelmy plate method. The interfacial properties were correlated to the percentage oil uptake by the coacervate phase. The relative hydrophobicity/lipophilicity of the oil influenced its uptake by complex coacervate droplets. The presence of surfactant affected oil uptake, depending on the HLB value of the surfactant or surfactant mixture. Uptake of squalane by the gelatin/acacia coacervates was found to be optimized by the addition of surfactants with HLB values in the range 2.5-6. The percentage uptake of oil decreased rapidly for systems prepared containing surfactants with HLB values outside this range. No correlation was observed between oil uptake by the coacervate phase and the interfacial tension of the oil and oil/surfactant systems with double-distilled deionized water.

Distribution of carbohydrate epitopes among disjoint subsets of leech sensory afferent neurons

Carbohydrate recognition plays an important role in the development of normal projections of sensory afferent neurons in the leech CNS. Four different carbohydrate epitopes are expressed by sensory afferents on their 130 kDa surface proteins: all sensory afferents share a common carbohydrate epitope (CE0) that helps them to enter and project diffusely across the synaptic neuropil; a restricted expression of three other carbohydrate epitopes (CE1, CE2, and CE3) serves to distinguish three subsets of sensory afferents. We examined the subsets of sensory afferents defined by their subset carbohydrate epitopes in the leech lip, skin, gut, and CNS. We established that the CE1, CE2, and CE3 subset epitopes define disjoint subsets of neurons by double labeling sensory afferents with monoclonal antibodies for different pairs of subset epitopes. We found that CE2 and CE3 afferents populate the lip and skin, but not the gut, and that these two subsets of sensory afferents have convergent projection patterns in the CNS. We found that CE1 afferents populate the gut and skin, but not lips; furthermore, their CNS projections diverge from those of CE2 and CE3 afferents. Our data fit the hypothesis that these carbohydrate epitopes are related to sensory modality of afferent subsets.

Molecular cloning and characterization of the cDNA coding for the biotin-containing subunit of 3-methylcrotonoyl-CoA carboxylase: identification of the biotin carboxylase and biotin-carrier domains

Soybean genomic clones were isolated based on hybridization to probes that code for the conserved biotinylation domain of biotin-containing enzymes. The corresponding cDNA was isolated and expressed in Escherichia coli through fusion to the bacterial trpE gene. The resulting chimeric protein was biotinylated in E. coli. Antibodies raised against the chimeric protein reacted specifically with an 85-kDa biotin-containing polypeptide from soybean and inhibited 3-methylcrotonoyl-CoA carboxylase (EC 6.4.1.4) activity in cell-free extracts of soybean leaves. Thus, the isolated soybean gene and corresponding cDNA code for the 85-kDa biotin-containing subunit of 3-methylcrotonoyl-CoA carboxylase. The nucleotide sequence of the cDNA and portions of the genomic clones was determined. Comparison of the deduced amino acid sequence of the biotin-containing subunit of 3-methylcrotonoyl-CoA carboxylase with sequences of other biotin enzymes suggests that this subunit contains the functional domains for the first half-reaction catalyzed by all biotin-dependent carboxylases--namely, the carboxylation of biotin. These domains are arranged serially on the polypeptide, with the biotin carboxylase domain at the amino terminus and the biotin-carboxyl carrier domain at the carboxyl terminus.

Evidence that v-Src-induced phospholipase D activity is mediated by a G protein

v-Src-induced increases in diglyceride are derived from phosphatidylcholine via a type D phospholipase (PLD) and a phosphatidic acid phosphatase. v-Src-induced PLD activity, as measured by PLD-catalyzed transphosphatidylation of phosphatidylcholine to phosphatidylethanol, is inhibited by GDP beta S, which inhibits G-protein-mediated intracellular signals. Similarly, v-Src-induced increases in diglyceride are also blocked by GDP beta S. In contrast to the PLD activity induced by v-Src, PLD activity induced by the protein kinase C agonist, 12-O-tetradecanoylphorbol-13-acetate (TPA), was insensitive to GDP beta S. Consistent with the involvement of a G protein in the activation of PLD activity by v-Src, GTP gamma S, a nonhydrolyzable analog of GTP that potentiates G-protein-mediated signals, strongly enhanced PLD activity in v-Src-transformed cells relative to that in parental BALB/c 3T3 cells. The effect of GTP gamma S on PLD activity in v-Src-transformed cells was observed only when cells were prelabeled with [3H]myristate, which is incorporated exclusively into phosphatidylcholine, the substrate for the v-Src-induced PLD. There was no difference in the effect of GTP gamma S-induced PLD activity on v-Src-transformed and BALB/c 3T3 cells when the cells were prelabeled with [3H]arachidonate, which is not incorporated into phospholipids that are substrates for the v-Src-induced PLD. Similarly, GDP beta S inhibited PLD activity in v-Src-transformed cells much more strongly than in BALB/c 3T3 cells when [3H]myristate was used to prelabel the cells. The GTP-dependent activation of PLD by v-Src was dependent upon the presence of ATP but was unaffected by either cholera or pertussis toxin. These data suggest that v-Src induces PLD activity through a phosphorylation event and is mediated by a cholera and pertussis toxin-insensitive G protein.

Influence of nuclear background on transcription of a chimeric gene (orf256) and coxI in fertile and cytoplasmic male sterile wheats

Crosses between Triticum timopheevi, as maternal donor, and T. aestivum can lead to cytoplasmic male sterile (cms) plants. The T. timopheevi derived mitochondrial DNA from parental, cms, and fertility-restored lines differs from that of T. aestivum derived mtDNA in the coxI gene region. Our previous results for cms lines showed that there is an open reading frame, orf256, upstream from coxI in T. timopheevi derived mtDNA that is not present in T. aestivum DNA. The 5' flanking region and the first 33 nucleotides of the coding region of orf256 are identical to the corresponding region of T. aestivum coxI, whereas the rest of orf256, including the 3' flank, is not related to coxI. Also, the organization of orf256 and coxI on a HindIII fragment from T. timopheevi derived mtDNA are identical in T. timopheevi, cms, and fertility-restored lines. We now report that the DNA sequence of orf256 is identical in T. timopheevi, cms, and fertility-restored lines. Major transcripts in cms and fertility-restored lines encode both orf256 and coxI with 5' termini like coxI mRNA of T. aestivum, whereas parental mitochondria from T. timopheevi have major transcripts with 5' termini within the orf256 coding region. Mitochondria from cms and fertility-restored lines have the potential to produce a protein that would not be present in parental T. timopheevi or in T. aestivum.

[Repair of heel defect with a free medial plantar flap]

The results of reconstruction of plantar heel defects with a local random flap or an island medial plantar flap have in a majority of cases been satisfactory. However, in cases of extensive plantar defects, local tissue transfers are almost impossible. Since 1988, 8 cases with extensive plantar defects have been treated using free medial plantar cutaneous or musculocutaneous flaps. All flaps survived. Six weeks postoperatively, full weight-bearing was obtained and normal activities were resumed. No ulceration in the flaps has been noted in the follow up period between 6 and 24 months, and the two point discrimination was from 20 to 24 mm. The paper particularly points out the importance of nerve repair in the reconstruction, because recovery of the protective sensation is the most important factor to prevent plantar ulceration, and is the basis for good operative results.

Pseudomonas aeruginosa possesses homologues of mammalian phenylalanine hydroxylase and 4 alpha-carbinolamine dehydratase/DCoH as part of a three-component gene cluster

Pseudomonas aeruginosa possesses a multigene operon that includes phenylalanine hydroxylase (PhhA; phenylalanine 4-monooxygenase, EC 1.14.16.1). phhA encodes PhhA (M(r) = 30,288), phhB (M(r) = 13,333) encodes a homologue of mammalian 4 alpha-carbinolamine dehydratase/homeodomain protein transregulator, and phhC encodes an aromatic aminotransferase (M(r) = 43,237). The reading frames specifying phhB and phhC overlap by 2 bases. The P. aeruginosa PhhA appears to contain iron and is pterin dependent. Unlike the multimeric mammalian hydroxylase, the native P. aeruginosa enzyme is a monomer. The P. aeruginosa PhhA is homologous with mammalian PhhA, tryptophan hydroxylase, and tyrosine hydroxylase. Expression of PhhA from its native promoter required phhB. This may suggest a positive regulatory role for phhB, consistent with the dual catalytic and regulatory roles of the corresponding mammalian homologue.

Epidermal growth factor induces the production of biologically distinguishable diglyceride species from phosphatidylinositol and phosphatidylcholine via the independent activation of type C and type D phospholipases

An early response to epidermal growth factor in A431 cells is the generation of diglyceride, a physiological activator of protein kinase C. By differentially prelabeling cellular phospholipids with [3H]arachidonate and [3H]myristate, which are incorporated primarily into phosphatidylinositol and phosphatidylcholine, respectively, we have found that epidermal growth factor induces an increase in diglyceride levels from both phosphatidylinositol and phosphatidylcholine via distinct mechanisms and kinetics. The epidermal growth factor-induced increase in phosphatidylinositol-derived diglyceride was transient and peaked at 5 min. As diglyceride levels dropped, there was a corresponding increase in phosphatidic acid, suggesting that the diglyceride is efficiently converted to phosphatidic acid by a diglyceride kinase. In contrast, epidermal growth factor-induced increases in phosphatidylcholine-derived diglyceride peaked at 30 min and remained elevated for greater than 2 h. The epidermal growth factor-induced increases in phosphatidic acid detected in [3H]myristate-prelabeled cells paralleled the increase in diglyceride, suggesting that the phosphatidylcholine-derived diglyceride is produced from phosphatidic acid via a phosphatidic acid phosphatase. Consistent with this hypothesis, epidermal growth factor also induced a protein kinase C-independent phospholipase D activity that was specific for phosphatidylcholine. These data suggest that epidermal growth factor induces diglyceride production from phosphatidylinositol and phosphatidylcholine via two distinct mechanisms: a rapid and transient induction of diglyceride that likely involves phospholipase c-gamma-mediated hydrolysis of phosphatidylinositol-4,5-bisphosphate and a slower, more sustained induction of diglyceride via a phospholipase D-mediated hydrolysis of phosphatidylcholine to produce phosphatidic acid, which is then converted to diglyceride by a phosphatidic acid phosphatase.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue distribution of somatostatin receptor subtype messenger ribonucleic acid in the rat

The tissue distribution of mRNA encoding five somatostatin receptor subtypes, SSTR1, SSTR2, SSTR3, SSTR4, and SSTR5, was determined in adult rat tissues by solution hybridization/nuclease protection analysis using sequence-specific cRNA probes. In the central nervous system, SSTR1 and SSTR2 mRNA were expressed widely, with highest levels in hippocampus, hypothalamus, cortex, and amygdala and expression of both isoforms in cerebellum and spinal cord. Expression of SSTR3 was also widespread, occurring in all brain regions examined, with the highest level of expression in the cerebellum. SSTR4 mRNA was detected in most brain regions, with highest levels occurring in the hippocampus, cortex, and olfactory bulb. No detectable levels were found in cerebellum. SSTR5 showed a unique pattern of expression in the central nervous system, being found primarily in the hypothalamus and preoptic area. In peripheral tissues, high levels of SSTR1 and SSTR2 mRNA were found in pituitary and spleen. SSTR1 mRNA was also found in the heart and intestine, SSTR2 was detected in pancreas, and both isoforms were expressed in stomach. Expression of SSTR3 was noted in heart, liver, stomach, intestine, kidney, spleen, and pituitary. The patterns of expression were similar for SSTR4 and SSTR3 mRNA; however, SSTR4 was not expressed in liver. SSTR5 was expressed predominantly in the pituitary, but detectible levels were observed in spleen and intestine. Thus, the SSTR subtype mRNA showed both a tissue-specific and overlapping pattern of expression. Taken together with SSTR-specific signal transduction systems, this probably explains the diverse physiological actions of somatostatin.

Influence of feeding schedule on chronopharmacological aspects of gentamicin in mice

The effects of the time of day of drug administration on the subchronic toxicity and pharmacokinetics of gentamicin, as well as the role of feeding schedule on circadian rhythms, were investigated in mice. ICR male mice were housed in a light-dark (LD) cycle (12:12) with food and water ad libitum (ALF) or under a time-restricted feeding (TRF) schedule (feeding time: 8 h during the light phase) for 1 day or 14 days before drug administration. The animals were given a single subcutaneous dose of gentamicin 180 mg/kg for the kinetic studies and subcutaneous doses of gentamicin 180 mg/kg/day for 14 days or 220 mg/kg/day for 18 days for the subchronic toxicity studies. A significant dosing-time dependency was shown for mortality and body weight loss, with higher values at midlight and lower ones at the middark (p < 0.05). A significant circadian rhythm was also found for gentamicin kinetics in ALF mice, with the highest clearance at middark and the lowest one at midlight (p < 0.01). The kinetic rhythm of gentamicin coincided well with the toxicity rhythm of the drug. The TRF schedule had a marked influence on the rhythms of gentamicin kinetics and toxicity, showing lowest clearance and higher toxicity at middark. The rhythm of subchronic toxicity of gentamicin seems to be due, at least in part, to the rhythm in kinetics and is strongly influenced by the feeding schedule. Thus, the timing of dosing is an important factor in the kinetics and the subchronic toxicity of gentamicin administration in mice, and the manipulation of feeding schedule can modify the rhythm of the toxicity by changing the rhythm of gentamicin kinetics.

v-Src activates a unique phospholipase D activity that can be distinguished from the phospholipase D activity activated by phorbol esters

Phospholipase D (PLD) activity, as measured by the transphosphatidylation of cellular phospholipids, is elevated in BALB/c 3T3 cells transformed by v-Src. Phorbol esters that activate protein kinase C (PKC) also increase PLC activity in BALB/c 3T3 cells. v-Src-induced PLD activity could be distinguished from phorbol ester-induced PLD activity by differential radiolabelling of phospholipids, which are the substrates of PLD. Both v-Src- and phorbol ester-induced PLD activity could be detected when phospholipids were prelabelled with either radiolabelled myristate or palmitate; however, only phorbol ester-induced PLD activity could be detected when either arachidonate or 1-O-alkyl-sn-glyceryl-3-phosphorylcholine (alkyl-lysoPC) was used to prelabel the phospholipids. The increased PLD activity in v-Src-transformed cells was not detected when the cells were prelabelled with either arachidonic acid or alkyl-lysoPC, which contains an ether linkage at sn-1 of the glycerol backbone. As both arachidonic acid and alkyl-lysoPC are incorporated into phosphatidylcholine (PC), the substrate for v-Src-induced PLD activity, these data suggest that the PLD activated by v-Src can distinguish PCs lacking arachidonic acid and ether linkages. Consistent with v-Src activating a PLD activity that is distinct from that activated by phorbol esters that activate PKC directly, neither depleting cells of PKC nor treatment with the protein kinase inhibitor, staurosporine, had any effect on v-Src-induced PLD activity, whereas both PKC depletion and staurosporine inhibited phorbol ester-induced PLD activity. Taken together, these data suggest that v-Src activates a PKC-independent PLD activity that is specific for a subpopulation of PC and distinct from the PLD activity induced by PKC activity induced by phorbol esters. The diacylglycerol produced from PC by the action of the v-Src-induced PLD may therefore be responsible for the activation of PKC by v-Src.

Regulation of hypothalamic preprogrowth hormone-releasing factor messenger ribonucleic acid expression in food-deprived rats: a role for histaminergic neurotransmission

To determine the component(s) of dietary protein that regulates GH-releasing factor (GRF) synthesis, we measured hypothalamic prepro-GRF mRNA by solution hybridization/nuclease protection analysis in food-deprived rats refed protein-free diets (PF) supplemented with individual amino acids. Adult male Sprague-Dawley rats were allowed free access to food (Fed), food deprived for 72 h (FD), or FD then refed for 72 h with a normal (NF) diet, a protein-free (PF) diet, or PF diets containing tyrosine, tryptophan (Trp), glutamic acid, or histidine (His). Food-deprived rats displayed the expected 80% reduction in hypothalamic prepro-GRF mRNA. Upon refeeding, levels were normalized in rats refed a normal diet, but not in those refed a PF diet alone or with tyrosine, Trp, or glutamic acid. In contrast, prepro-GRF mRNA was restored to 70% of Fed values by a PF diet with His. Supplementing a PF diet with His was sufficient to maintain hypothalamic prepro-GRF mRNA expression, as 3 days of feeding replete rats with PF diet or PF diet with added Trp resulted in a 50% reduction in prepro-GRF mRNA, whereas levels were reduced 25% by feeding animals a PF diet with His. Groups of rats allowed free access to food were treated for 72 h with two daily injections of 100 mg/kg alpha-fluoremethylhistidine, a specific irreversible inhibitor of histidine decarboxylase, to determine if the effect of His on prepro-GRF mRNA depended on neural conversion to histamine. alpha-Fluoremethylhistidine-treated rats showed a 40% reduction in hypothalamic prepro-GRF mRNA, with no concomitant change in preproneuropeptide-Y or preprosomatostatin. These data indicate that decreased hypothalamic prepro-GRF mRNA in FD rats is due in part to the lack of dietary and provide clear evidence for a role of the histaminergic neural system in the regulation of hypothalamic GRF expression.

Vif is crucial for human immunodeficiency virus type 1 proviral DNA synthesis in infected cells

The human immunodeficiency virus type 1 (HIV-1) vif gene encodes a 23-kDa protein of unknown function, also produced by most other known lentiviruses. Vif was found to be essential for the spread of HIV-1 in peripheral blood lymphocytes and in primary macrophages, as well as in some but not all established T-cell lines. Vif was required at the stage of viral particle formation, for cell-to-cell as well as for cell-free transmission of HIV-1. Accordingly, vif-defective viruses could be complemented by the expression of vif in the producer but not in the target cell. vif-defective virions contained wild-type amounts of Gag and Env proteins, reverse transcriptase, integrase, genomic RNA, and partial reverse transcripts. Most importantly, they could enter cells normally, and the vif defect could not be rescued through the use of HIV(MLV [murine leukemia virus]) pseudotypes. Instead, vif-mutant viruses were severely impaired in their ability to complete the synthesis of proviral DNA, once internalized in the target cell. These results suggest that Vif plays a role which is novel for a retroviral protein, in allowing the processing and/or the transport of the internalized HIV core.

The aroQ-encoded monofunctional chorismate mutase (CM-F) protein is a periplasmic enzyme in Erwinia herbicola

Enteric bacteria possess two species of chorismate mutase which exist as catalytic domains on the amino termini of the bifunctional PheA and TyrA proteins. In addition, some of these organisms possess a third chorismate mutase, CM-F, which exists as a small monofunctional protein. The CM-F gene (denoted aroQ) from Erwinia herbicola was cloned and sequenced for the first time. A strategy for selection by functional complementation in a chorismate mutase-free Escherichia coli background was devised by using a recombinant plasmid derivative of pUC18 carrying a Zymomonas mobilis tyrC insert which encodes cyclohexadienyl dehydrogenase. The aroQ gene is 543 bp in length, predicting a 181-residue protein product having a calculated molecular mass of 20,299 Da. The E. herbicola aroQ promoter is recognized by E. coli, and a putative sigma-70 promoter region was identified. N-terminal amino acid sequencing of the purified CM-F protein indicated cleavage of a 20-residue signal peptide. This was consistent with the monomeric molecular mass determined for the enzyme of about 18,000 Da. The native enzyme is a homodimer. The implied translocation of CM-F was confirmed by osmotic shock experiments which demonstrated a periplasmic location. Immunogold electron microscopy indicated a polar localization within the periplasm. Polyclonal antibody raised against E. herbicola CM-F did not cross-react with the CM-F protein from the closely related Serratia rubidaea, as well as from a number of other gram-negative bacteria. Furthermore, when the E. herbicola aroQ gene was used as a probe in Southern blot hybridizations with EcroRI digests of chromosomal DNA from S. rubidaea and other enteric organisms, no hybridization was detected at low stringency. Thus, the aroQ gene appears to be unusually divergent among closely related organisms. The deduced CM-F amino acid sequence did not exhibit compelling evidence for homology with the monofunctional chorismate mutase protein of Bacillus subtilis.

Molecular cloning and sequencing of a human somatostatin receptor, hSSTR4

We recently reported the cloning of a somatostatin receptor (SSTR) subtype from a rat genomic library designated rSSTR4. In the present study, we report the cloning of the human SSTR4 gene. A human genomic library was screened with a 1.2 kb fragment of rSSTR4 containing the full open reading frame and a genomic clone, hSSTR4, was isolated. The deduced amino acid sequence of this clone encoded a protein of 388 amino acids and is a member of the G-protein coupled receptor superfamily. Comparison of rat and human SSTR4 sequences demonstrated 89% identity. In addition, the sequence of hSSTR4 shows 61%, 46%, and 47% sequence identity with previously identified isoforms hSSTR1, hSSTR2, and hSSTR3, respectively.

Pituitary and hypothalamic insulin-like growth factor-I (IGF-I) and IGF-I receptor expression in food-deprived rats

The present study was designed to evaluate a possible role for the insulin-like growth factor-I (IGF-I) system in mediating the suppression of growth hormone (GH) secretion observed in food-deprived rats by measuring IGF-I mRNA, receptor concentration and receptor mRNA in neuroendocrine tissues (hypothalamus and pituitary). Rats were deprived of food (food-deprived) for 72 h or had free access to food (fed). Tissues were processed for measurement of steady-state levels of: (a) IGF-I and IGF-I receptor mRNA (by solution hybridization/RNase protection assay); (b) IGF-I in serum and tissue extracts (by RIA) and (c) IGF-I displaceable [125I]IGF-I binding to plasma membrane preparations. Food deprivation resulted in decreased serum and liver levels of IGF-I. Kidney IGF-I mRNA levels were reduced 80% in food-deprived rats with a concomitant increase in IGF-I receptor concentration and mRNA levels. Refeeding of food-deprived rats fully normalized these perturbations. Pituitary IGF-I content was reduced 50% in food-deprived rats while IGF-I mRNA levels were unaffected. A modest increase was seen in pituitary IGF-I receptor concentration; however, IGF-I receptor mRNA levels were not changed. Hypothalamic IGF-I mRNA content was reduced in 72 h food-deprived rats while IGF-I receptor binding capacity and mRNA were unaffected. In conclusion, IGF-I mRNA levels are decreased in liver, kidney and hypothalamus together with a reduction in plasma IGF-I in food-deprived rats but is unaffected in anterior pituitary. IGF-I receptor gene expression and binding capacity are coordinately regulated in kidney and hypothalamus, but not in the pituitary.(ABSTRACT TRUNCATED AT 250 WORDS)

Bending rigidity of SOPC membranes containing cholesterol

Bilayer membranes in the fluid state exhibit a large resistance to changes in surface area, negligible resistance to surface shear deformation, and a small but finite resistance to bending. The presence of cholesterol in the membrane is known to increase its resistance to area dilation. In this report, a new method for measuring bilayer membrane bending stiffness has been used to investigate the effect of cholesterol on the bending rigidity of SOPC (1,stearoyl-2,oleoyl-phosphatidylcholine) membranes. The curvature elasticity (kc) for membranes saturated with cholesterol was measured to be 3.3 x 10(-19) J, approximately 3-fold larger than that the modulus for cholesterol-free SOPC membrane. These findings are consistent with previous measurements of bending stiffness based on thermal fluctuations, which showed a similar approximately 3-fold increase in the modulus with cholesterol addition (Evans and Rawicz, 1990, Phys. Rev. Lett. 64:2094) and provide further substantiation of the important contribution that cholesterol makes to membrane cohesion and stability.

A dominant negative Raf-1 mutant prevents v-Src-induced transformation

A vector expressing a dominant negative mutant of Raf-1 was stably introduced into BALB/c 3T3 cells expressing a temperature-sensitive derivative of v-Src. High levels of the Raf-mutant were detected in these cells. Expression of the Raf-1 mutant blocked v-Src-induced transformation, as determined by reversion to a flat non-transformed morphology and the inability to form colonies in soft agar. Cells transfected with the parental vector lacking the mutant Raf-1 could be transformed by v-Src. These data suggest that intracellular signals activated by v-Src that are mediated by Raf-1 are required for transformation by v-Src.

Molecular cloning and functional expression of a brain-specific somatostatin receptor

The PCR and conventional library screening were used to clone the brain-specific somatostatin receptor rSSTR-4 from a rat genomic library. The deduced amino acid sequence encodes a protein of 384 amino acids and displays structural and sequence homologies with members of the G protein-receptor superfamily. The amino acid sequence of rSSTR-4 is 60% and 48% identical to that of somatostatin receptors SSTR-1 and SSTR-2, respectively, two recently cloned subtypes. Competition curve analysis of the binding properties of the receptor transiently expressed in COS-1 cells revealed a higher apparent affinity for somatostatin 14 than for somatostatin 28. In contrast, the somatostatin analogs SMS 201-995, IM 4-28, and MK-678 failed to displace specific binding in transfected cells. These characteristics resemble the pharmacological binding properties of the previously described brain-specific somatostatin-receptor subtype. Examination of the tissue distribution of mRNA for rSSTR-4 revealed expression limited to various brain regions with highest levels in the cortex and hippocampus. Thus, based on the pharmacology and tissue localization of this receptor, we conclude that rSSTR-4 represents a brain-specific somatostatin receptor.

Cytoplasmic male sterility and fertility restoration in wheat are not associated with rearrangements of mitochondrial DNA in the gene regions for cob, coxII, or coxI

In comparing the genetic organization and exploring the molecular basis of cytoplasmic male sterility (CMS) in wheat, mitochondrial DNAs (mtDNA) from Triticum aestivum, T. timopheevi, CMS alloplasmic wheat with T. aestivum nucleus and T. timopheevi mitochondria, and fertility-restored lines were compared by hybridization analysis with specific probes for three gene regions: coxII, cob, and coxI. Minor differences between T. aestivum- and T. timopheevi-derived sources were found for gene regions for coxII and cob. For coxI, there are significant differences between T. timopheevi-derived mtDNAs and T. aestivum mtDNA extending beyond an 8 kb distance. All T. timopheevi-derived mtDNA sources have a chimeric gene region (orf256) with part of the upstream coxI gene region, including some coxI-coding region, preceding coxI. The part of orf256 that does not include any of coxI and the 3'-flanking region of CMS coxI are not found in T. aestivum mtDNA. Neither orf256 nor the CMS 3'-flanking region of coxI are found in T. timopheevi or T. aestivum chloroplastic or nuclear DNA. There do not appear to be DNA sequence differences for the three gene regions studied that are related to either CMS or fertility-restored states.

Motor components of the trigeminal nerve and organization of the mandibular arch muscles in vertebrates. Phylogenetically conservative patterns and their ontogenetic basis

The peripheral branching pattern of the mandibular ramus of the Vth cranial nerve and the organization of the trigeminal motor column are highly conserved in craniate phylogeny regardless of the vast modifications in attachments and structure of the mandibular arch musculature. Proximal, intermediate and distal series of mandibular nerve branches supply three major muscle groups and are in register with three neuronal populations of the trigeminal motor column. The adult branching pattern is established in response to the differentiation of mandibular muscles and is important in determining the organization of the motor nucleus of V. The innervation of the muscles of the mandibular segment of the head, and the location of motoneurons reflect their segmental origins and are reliable criteria for homologizing mandibular muscles among the craniates.

[An epidemiological analysis on the geographic factors of esophageal cancer]

The author collects the data of esophageal cancer mortality (1971-1973) of 78 counties in Hubei Province and the data of topography, climate, soil, rock formation and geochemical elements, including 40 suspected factors. The method of linear correlation and multiple stepwise regression are used for the comprehensive analysis of relation between the geographical factors and esophageal cancer. The result is that four factors metamorphic rock, zinc, copper, chromium are suspected factors. It suggests that the four factors will need future study.

Refinement of dendritic arbors along the tonotopic axis of the gerbil lateral superior olive

We have investigated the development of dendritic arbors in a central auditory nucleus in the Mongolian gerbil, the lateral superior olive (LSO). The morphology of these arbors has been shown to vary with tonotopic position in adults, with high frequency neurons having a more restricted field. In the present study, qualitative observations were made on horseradish peroxidase-filled neurons from animals 1-11 days postnatal, and quantitative results were obtained from Golgi-impregnated material from animals 10 days postnatal and older. The tonotopic position of each cell was computed as a percent of the total distance along the LSO. The dendritic arbors of high frequency neurons became spatially constrained along the frequency axis during the 3rd postnatal week, while those in the low frequency region retained a broader arborization into adulthood. This refinement was correlated with a decrease in total dendritic length and the number of branch points per neuron, particularly in the high frequency projection region. The distribution of octave bandwidths to which single LSO neurons responded in 13-16 day animals showed a similar course of maturation across the tonotopic axis: high frequency neurons responded to a larger number of octaves, and with greater variability, than those in adults. These data suggest that a specific alteration in dendrite morphology, which occurs after the onset of response to airborne sound, may contribute to adult frequency selectivity.

Local and nonlocal curvature elasticity in bilayer membranes by tether formation from lecithin vesicles

Bilayer membranes exhibit an elastic resistance to changes in curvature. This resistance depends both on the intrinsic stiffness of the constituent monolayers and on the curvature-induced expansion or compression of the monolayers relative to each other. The monolayers are constrained by hydrophobic forces to remain in contact, but they are capable of independent lateral redistribution to minimize the relative expansion or compression of each leaflet. Therefore, the magnitude of the expansion and compression of the monolayers relative to each other depends on the integral of the curvature over the entire membrane capsule. The coefficient characterizing the membrane stiffness resulting from relative expansion is the nonlocal bending modulus kr. Both the intrinsic (local) bending modulus (kc) and the nonlocal bending modulus (kr) can be measured by the formation of thin cylindrical membrane strands (tethers) from giant phospholipid vesicles. Previously, we reported measurements of kc based on measurements of tether radius as a function of force (Song and Waugh, 1991, J. Biomech. Engr. 112:233). Further analysis has revealed that the contribution from the nonlocal bending stiffness can be detected by measuring the change in the aspiration pressure required to establish equilibrium with increasing tether length. Using this approach, we obtain a mean value for the nonlocal bending modulus kr of approximately 4.1 x 10(-19)J. The range of values is broad (1.1-10.1 x 10(-19)J) and could reflect contributions other than simple mechanical equilibrium. Inclusion of the nonlocal bending stiffness in the calculation of kc results in a value for that modulus of approximately 1.20 +/- 0.17 x 10(-19)J, in close agreement with values obtained by other methods.

Nuclear deoxyribonucleic acid content measured by static cytometry: important prognostic association for patients with clinically localized prostate carcinoma treated by external beam radiotherapy

To determine if relative nuclear deoxyribonucleic acid (DNA) content is an important prognostic parameter for patients with clinically localized prostate carcinoma treated by external beam radiotherapy, we performed static DNA cytometry on archival paraffin embedded prostate needle biopsy specimens obtained before treatment. DNA content was measured with the Zeiss IBAS 2000 Image Analyzer and the Feulgen staining method. Tumor samples from 65 patients with clinically localized carcinoma of the prostate treated with at least 6,000 cGy. from 1974 to 1980 were studied. Patients and tumors were divided into 2 groups: group 1 - 31 patients with relative DNA content less than 1.5 times normal and group 2 - 34 patients with relative DNA content greater than 1.5 times normal. The prostate cancer nonprogression rate at 10 years was 64% for group 1 and 11% for group 2. Prostate cancer cause specific survival at 10 years was 73% for group 1 and 20% for group 2. These differences are highly significant (p less than 0.0001). By contrast, stratification and analysis according to tumor clinical stage, Mayo histological nuclear grade or Gleason score proved not to be as significant. Cox multivariate analysis also identified DNA content as the most important independent variable for cancer specific survival and progression. Nuclear DNA content measured by static cytometry appears useful in identifying those patients with clinically localized prostate carcinoma who may have a favorable probability of long-term disease control by external beam radiotherapy.

A comparison of various loading configurations of the proximal femur for the evaluation of reconstructive surgical procedures

The study was designed to evaluate the effect of different loading configurations on stem and bone stresses in simulated total hip arthroplasty. The traditional experiment design of loading the model through the head of the prosthesis by the resultant joint force was compared with a more realistic model which included an abductor strap to simulate the abductor muscle force. In addition, an alternative experiment design was evaluated in which a loading arm was clamped directly on to the head of the prosthesis. The results show that loading the model by the resultant joint force not only changes the magnitude of the stresses but also the stress distribution compared to the abductor muscle model. The new experiment design closely approximates stresses seen in the abductor muscle model below the lesser trochanter. In the proximal region, the stresses are increased on the medial side and decreased on the lateral side. The advantages of the proposed loading model are: (a) easy and reproducible set-up and alignment is facilitated, (b) different positions of the femur (flexion, extension) can be simulated and (c) a more realistic stress distribution and magnitude is achieved.

Adaptive Ho-Kashyap rules for perceptron training

Three adaptive versions of the Ho-Kashyap perceptron training algorithm are derived based on gradient descent strategies. These adaptive Ho-Kashyap (AHK) training rules are comparable in their complexity to the LMS and perceptron training rules and are capable of adaptively forming linear discriminant surfaces that guarantee linear separability and of positioning such surfaces for maximal classification robustness. In particular, a derived version called AHK II is capable of adaptively identifying critical input vectors lying close to class boundaries in linearly separable problems. The authors extend this algorithm as AHK III, which adds the capability of fast convergence to linear discriminant surfaces which are good approximations for nonlinearly separable problems. This is achieved by a simple built-in unsupervised strategy which allows for the adaptive grading and discarding of input vectors causing nonseparability. Performance comparisons with LMS and perceptron training are presented.

Double-edged limit of total fertility rates

In this paper we present the accurate estimation of total fertility rates, prove the theorem of upper and lower bounds of double-edged limit and provide the formulas of upper and lower bounds of total fertility rates. Based on these estimations and statistical data, we calculate the upper and lower bounds of the double-edged limit for 46 countries including China. Furthermore, we describe the positive growth rate, negative growth rate and zero growth rate of population development. These results are of great importance for us to control population not only in theory but also in practice.

Electron microscopic studies of the endoplasmic reticulum in whole-mount cultured cells fixed with potassium permanganate

A method for visualizing the endoplasmic reticulum and other membrane organelles in whole-mount cells with a standard, 60-kV transmission electron microscope has been developed. By use of a new formulation of potassium permanganate as a fixative, intracellular membranes were preserved and stained, while cytosolic proteins were digested, giving a pattern of membranous organelles against a clear background, suitable for transmission EM of whole-mount cells at 60 kV. Mitochondria, lysosomes, and ER were clearly visible in whole-mount cells fixed by this method. We have employed this technique to examine the organization of the ER in a variety of different cell lines. This method also allowed visualization of the three-dimensional organization, relationships, and fine structure of mitochondria. With prolonged permanganate fixation, mitochondrial cristae were clearly visible in whole-mount cells. This method was also useful for fixation and staining of thin sections, and allowed examination of thicker sections than previously possible, thus giving improved imaging of organelle relationships and fine structure. Using this method, we have examined the ER, mitochondria, and Golgi in thin section.

[Preliminary study on soilless cultivation techniques of Panax quinquefolium L]

Our experiment has shown 1. Vermiculite with sand (volume 1:1) is a good substrate of soil for American Ginseng. The yield and contents of ginsenoside of American ginseng in this soilless substrate are a little higher than those in ordinary soil. 2. This kind of substrate can be used continuously with fewer occurrences of insect pest and plant diseases and contributes significantly to the reduction of production cost.

Structural analysis of the conformational domains involved in neutralization of bovine coronavirus using deletion mutants of the spike glycoprotein S1 subunit expressed by recombinant baculoviruses

Two conformation-dependent neutralizing epitopes, A and B, have been mapped to the S1 subunit of the S spike glycoprotein of bovine coronavirus (BCV). In order to characterize the structure of these antigenic sites, we constructed a series of cDNA clones encoding deleted or truncated S1 derivatives and expressed the modified genes in insect cells using recombinant baculoviruses. Monoclonal antibodies directed against epitopes A and B recognized only the mutant S1 polypeptides containing amino acids 324-720, as demonstrated by immunoprecipitation and Western blot analysis in the absence of beta-mercaptoethanol. In addition, two domains within this region were identified and only mutants containing both domains were immunoreactive, indicating that both were critical in the formation of the antigenic determinants. One domain was localized between residues 324 and 403 and the other at residues 517-720. Deletion of either domain inhibited extracellular secretion of the mutant proteins whereas mutants containing both or none of the domains were secreted efficiently. This observation suggests a vital function of the native conformation of the S1 protein in both antigenic structure and intracellular transport. Antigenic determinants A and B were not distinguished, but these determinants appeared to require both domains for epitope formation. Our results suggest that the antigenic determinants formed by two domains are likely associated with the probable polymorphic region of the BCV S1 subunit.

Effects of dietary selenium and fish oil (MaxEPA) on arachidonic acid metabolism and hemostatic function in rats

This study investigated whether hemostatic function can be modified by both the consumption of fish oil and the level of dietary selenium. Male Sprague-Dawley rats were fed for 8 wk semipurified diets containing 7% corn oil (by wt) or 5.5% fish oil (MaxEPA) plus 1.5% corn oil with or without selenium supplementation. Consumption of the four diets caused no difference in weight gain, food intake or plasma malondialdehyde content. The selenium-supplemented rats had significantly higher levels of selenium and glutathione peroxidase activity in plasma. Fish oil feeding decreased ADP-induced platelet aggregation and increased bleeding time. The level of dietary selenium and type of oil interacted to influence the production of 6-keto-prostaglandin F1 alpha: more was produced when corn oil was fed in the selenium-deficient diets. These data suggest that the effect of dietary selenium on hemostatic function and the production of eicosanoids is minor.

Pituitary insulin-like growth factor-I content and gene expression in the streptozotocin-diabetic rat: evidence for tissue-specific regulation

Insulinopenic diabetes mellitus in the rat is associated with reduced circulating levels of insulin-like growth factor-I (IGF-I), resulting primarily from decreased IGF-I synthesis in liver and extrahepatic sites. Plasma GH levels in these animals are also suppressed, with loss of episodic secretion and decreased pituitary synthesis. Intrapituitary IGF-I has been postulated to exert local autocrine/paracrine negative feedback regulation on GH synthesis and secretion. The present studies were designed to examine regulation of pituitary IGF-I peptide content and gene expression in insulinopenic streptozotocin (STZ)-diabetic rats compared to that in liver and testis. Serum IGF-I levels were reduced by 86% in STZ-diabetic rats together with reduction of IGF-I content in liver (53%) and testis (74%; all P less than 0.001 vs. control). Concomitantly, liver and testicular IGF-I mRNA levels were reduced by 90% (P less than 0.001 vs. control). Insulin treatment restored IGF-I peptide levels in serum, liver, and testis toward normal, with a partial but significant increase in liver IGF-I mRNA. In contrast, pituitary IFG-I peptide content increased by 69% in STZ-diabetic rats (P less than 0.001 vs. control), with no change in IGF-I gene expression. Insulin treatment completely reversed the rise of pituitary IGF-I peptide content. These results demonstrate a novel discordance in the regulation of IGF-I gene expression and peptide content between pituitary and other tissues in STZ-induced diabetic rats. Elevated IGF-I levels in the pituitaries of these animals may partly explain the suppressed GH synthesis and secretion seen in STZ-diabetic rats and provide further evidence for a potential autocrine or paracrine role of pituitary IGF-I in GH regulation.

An analysis of sex ratio of the elderly in Heilongjiang province

The authors analyze data concerning the sex ratio among those aged 60 and over living in Heilongjiang province, China. "Data from...three population censuses and the 1987 1% sample survey of Heilongjiang Province both [indicate] that the sex ratio of the elderly population is without exception higher than the sex ratio of the whole population...." Some reasons for this differential are discussed, including migration and excess female mortality.

[Image processing of topographic EEG in epilepsy]

The processing of epileptic computerized topographical EEG (CTE) with the principle of image enhancement and point-by-point process was reported. The results indicated that the high potential distribution of CTE markedly reduced, the focus location was prominent and the mirror nearly disappeared after processing CTE image. The difference increased between the spike grey and the fast wave. This is advantageous to the surgical treatment of epileptic focus in brain.

Primary adenocarcinoma of the bladder: favorable prognostic significance of deoxyribonucleic acid diploidy measured by flow cytometry

Flow cytometric nuclear deoxyribonucleic acid ploidy analysis was done successfully on 38 specimens of primary bladder adenocarcinoma treated between 1954 and 1985. Of the specimens 10 (26%) were deoxyribonucleic acid diploid, 8 (21%) were tetraploid and 20 (53%) were aneuploid. Distribution of ploidy patterns between the 14 histological low grade and 24 high grade tumors was similar. Of 38 tumors 35 (92%) showed muscle invasion. One tumor arose in a previously exstrophied bladder, 10 were of urachal origin and 27 arose in an anatomically normal bladder. Of the urachal origin tumors 80% were deoxyribonucleic acid aneuploid. At 5 and 10 years after diagnosis 80 and 70%, respectively, of the patients with diploid tumors were free of disease. By contrast, at 5 and 10 years after treatment only 20 and 12%, respectively, of the patients with nondiploid tumors have not had disease progression (p less than 0.001 log-rank test). None of the 6 patients with diploid, high grade, high stage, muscle invasive tumors had subsequent progression. In contrast, 16 of 17 patients (94%) with high grade, high stage, nondiploid tumors had either local or distant tumor recurrence (p less than 0.0005). Nuclear deoxyribonucleic acid ploidy pattern appears to be the most significant prognostic information currently available to stratify expected prognosis for patients with muscle invasive adenocarcinoma of the bladder. This test probably should be a standard tool in the clinical management of patients with this rare bladder malignancy.

Influence of food deprivation in the rat on hypothalamic expression of growth hormone-releasing factor and somatostatin

Food deprivation in the rat is associated with a reduction in serum GH levels characterized by suppression of high amplitude GH bursts and a decrease in the duration of secretory episodes. The mechanism(s) mediating this response is unknown. The present studies were designed to evaluate the role of hypothalamic factors potentially responsible for abnormal GH dynamics in food-deprived rats by measuring hypothalamic prepro-GH-releasing factor (GRF) and preprosomatostatin (SRIF) mRNA and peptide levels in adult male Sprague-Dawley rats after 72 h of food deprivation or free access to food. Hypothalamic prepro-GRF mRNA was reduced 80% in food-deprived rats compared to that in fed controls (P less than 0.001), while GRF content was unchanged. Levels of prepro-SRIF mRNA in food-deprived rats were similar to those in controls, as was hypothalamic SRIF content. The time course of hypothalamic prepro-GRF mRNA reduction was determined in groups of rats food-deprived for 24, 48, or 72 h and revealed a significant (30%) reduction of prepro-GRF mRNA (P less than 0.05 vs. fed) by 24 h, with maximal reduction (80%) by 48 h. Refeeding groups of animals for up to 72 h after they had been food-deprived for 72 h resulted in restoration of prepro-GRF mRNA levels to 50% of control levels by 24 h (P less than 0.05 vs. fed) and a return to control values by 48 h. These data suggest that decreased GRF gene expression and possibly GRF release play a major role in the loss of pulsatile GH secretion seen in this model of nutrient deprivation.

Ultrastructural localization of prolactin and chromogranin B messenger ribonucleic acids with biotinylated oligonucleotide probes in cultured pituitary cells

A technique for the subcellular localization of prolactin and chromogranin B messenger RNAs (mRNA) in pituitary adenomas by in situ hybridization with biotinylated oligonucleotide probes is described. Ultrastructural examination revealed clusters and individual gold particles in the cytoplasm with this pre-embedding in situ hybridization method. Prolactinomas expressed both prolactin and chromogranin B mRNA, whereas the null cell adenoma expressed only chromogranin B mRNA. Sections of positively labeled cells contained up to 30 gold particles/cell. Treatment of cells with RNAse before hybridization reduced the number of gold particles to less than 1/cell. These results indicate that biotinylated oligonucleotide probes can be used to localize different mRNAs in cultured pituitary cells at the ultrastructural level to study the processing of these molecules within specific cells and for more precise correlation of molecular function with ultrastructural morphology.

Bilayer membrane bending stiffness by tether formation from mixed PC-PS lipid vesicles

Recently, a new approach to measure the bending stiffness (curvature elastic modulus) of lipid bilayer membrane was developed (Biophys. J., Vol. 55; pp. 509-517, 1989). The method involves the formation of cylindrical membrane strands (tethers) from bilayer vesicles. The bending stiffness (B) can be calculated from measurements of the tether radius (Rt) as a function of the axial force (f) on the tether: B = f.Rt/2 pi. In the present report, we apply this method to determine the bending stiffness of bilayer membranes composed of mixtures of SOPC (1-stearoyl-2-oleoyl phosphatidyl choline) and POPS (1-palmitoyl-2-oleoyl phosphatidyl serine). Three different mixtures were tested: pure SOPC, SOPC plus 2 percent (mol/mol) POPS, and SOPC plus 16 percent POPS. The bending stiffness determined for these three different lipid mixtures were not significantly different (1.6-1.8 x 10(-12) ergs). Because POPS carries a net negative charge, these results indicate that changes in the density of the membrane surface charge have no effect on the intrinsic rigidity of the membrane. The values we obtain are consistent with published values for the bending stiffness of other membranes determined by different methods. Measurements of the aspiration pressure, tether radius and the tether force were used to verify a theoretical relationship among these quantities at equilibrium. The ratio of the theoretical force to the measured force was 1.12 +/- 0.17.

Direct embryogenesis from single mesophyll protoplasts in alfalfa (Medicago sativa L.)

We used a tetraploid clone derived from an anther culture operation of 'Ladak' alfalfa to study the pathway of direct embryogenesis from leaf-mesophyll protoplasts. About 72% of the protoplasts divided, and 7% of those produced proembryos. Approximately 38% of the proembryos developed into green embryos, and 33% initiated calluses. Other proembryos dedifferentiated into calluses which later redifferentiated embryos. Sixteen percent of the embryos developed directly into plants, whereas 81% produced plants indirectly via secondary embryos. The remaining 3% of the primary embryos failed to develop into plants. The lowest plating efficiency for direct embryogenesis was 0.3%. The high percentage of direct embryogenesis observed was related to the genetic nature of the clone, low density of liquid medium, low protoplast culture density, and the composition of culture media.