Biochemical and mechanical characterization of enzyme-digestible hydrogels

Albumin-cross-linked hydrogels were prepared by free radical polymerization using 1-vinyl-2-pyrrolidinone as a monomer and functionalized albumin as a crosslinking agent. The degree of chemical cross-linking was controlled by varying the degree of albumin functionality and the concentration of albumin. With emphasis placed on the potential use of these hydrogels for long-term oral drug delivery, gel characterization studies examined both the swelling and the mechanical properties in the absence and presence of pepsin. In the absence of pepsin, the equilibrium swelling ratio in simulated gastric fluid ranged from 17 to 55, depending on the degree of albumin functionality and the albumin concentration. Swelling was pH dependent at pH's greater than 7. The uptake of solvent into the dried hydrogels was determined to be Fickian. The integrity of swelling gels was dependent on the concentration of the functionalized albumin as well as on the degree of albumin functionality. In the presence of pepsin, a predominance of either surface or bulk degradation was observed, depending on the functionality of the albumin used as a cross-linker. Gel integrity during pepsin degradation also showed a marked dependence on the albumin functionality.

A high density cell culture system for generation of human lymphokine-activated killer (LAK) cells for clinical use in adoptive immunotherapy

A high density cell culture system has been developed for large-scale production of lymphokine-activated killer (LAK) cells from peripheral blood lymphocytes (PBLs) of malignant tumor patients. The system consists of a culture bag, which has two compartments separated by a semipermeable membrane, and an external rotator. The system allows for a long-term, at least 4 weeks, culture of LAK cells at high cell density in the inner compartment. The collected PBLs were first divided between the two culture bags and cultured without harvesting for 7-10 days to obtain LAK cells. Half of the LAK cells from each bag was administered to patients twice a week for clinical trials. Culture of the remaining half was continued following addition of a fresh culture medium. LAK cells were transferred to patients alternatively from each bag for the following 2-3 weeks. The total number of LAK cells administered amounted to 3.9-9.8 (mean 5.8) times more than the PBLs collected by leukapheresis (n = 10). The 5 x 10(6)/ml of PBLS of the initial concentration reached a maximum of 2 x 10(7)/ml. Our system does not need for a CO2 incubator. Cytotoxicity of the LAK cells was evaluated in 4 hr 51Cr release assays. Mean cytotoxicity at maximum cell density was 95.4 +/- 3.2% against ONS-12 (a human glioma cell) and 84.8 +/- 3.0% against Daudi cells (n = 10), but gradually decreased to about 50% at the end of fourth week of the culture period. Cell viability of the LAK cells was normally over 80% through the entire culture period.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-2 induces motility of human lymphocytes, but not their mobility

Interleukin-2 induces cytotoxic and antitumor activities of human lymphocytes. For the expression of these activities, the cytoskeletal system is probably activated. This study was do;ne to find if interleukin-2 causes cell movement. Lymphocytes were incubated with interleukin-2, and their morphology and motile activities were studied. After 72 hr of incubation, some 29% of lymphocytes were larger than before; nucleoli had formed and the microvilli were well-developed. The membrane potential of the lymphocytes increased during incubation. Motility under agar after 3 days of incubation with interleukin-2 was examined. Cells aggregated in clumps in the incubation well, and migration was not observed. When mobility was examined with Boyden's method, fewer cells incubated with interleukin-2 migrated than in control preparations. Cells incubated with interleukin-2 were extracted with Triton X-100. The extract obtained had three more bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis than the controls. The band were at the positions for the molecular weights of 270,000-300,000. We concluded that interleukin-2 activated the motility of lymphocytes, but not their mobility.

Goblet cell carcinoid of the appendix

We have reviewed all cases of goblet cell carcinoid in the Department of Pathology, Edinburgh University. Of the 10 cases identified, two had died as a result of the tumour. This would suggest a poorer prognosis than is generally recognized. Those patients who subsequently had progression of their disease were not predicted by histological criteria. Because of the unpredictable behaviour of these tumours we recommend that such patients should correctly be treated by a right hemicolectomy.

Effect of aggregation of histone octamers in high-salt solutions on circular dichroism spectra

The circular dichroism (CD) of freshly prepared chicken erythrocyte core histones has been reexamined in high concentrations of ammonium sulfate and sodium chloride, conditions which cause drastic changes in the solubility and aggregative properties of these proteins. After sample clarification by ultracentrifugation, no significant net changes are detected in the secondary structure of the core histones in the range of 2.0-2.5 M ammonium sulfate. There is also no significant difference between the CD spectra of histone solutions in 2 M sodium chloride and clarified solutions of histones in high concentrations of ammonium sulfate. It was observed that sample clarification by ultracentrifugation immediately prior to taking CD spectra was necessary for signal stabilization, especially under conditions which begin to favor crystallization of the histones.

Assessment of bilirubin clearance capacity of a newly developed ion-exchange adsorption column and its possible use as a supportive therapy in hepatorenal syndrome

We assessed the bilirubin reduction capacity of three different types of devices in vitro: a high-permeable membrane column for double-filtration plasmapheresis (DFP) (Evaflux 2A, Kuraray, Japan), and non-coated charcoal column for hemoperfusion (HP) (N-180, Asahi Medical, Japan), and ion-exchange columns for plasma adsorption (PA) (BR-350, Asahi Medical, Japan, and B-001, Kuraray, Japan). A column for DFP reduced the concentration of low-molecular proteins effectively such as plasma bilirubin and bile acids in an albumin-dependent manner. A charcoal column adsorbed low-molecular substances preferentially. But in these two columns, the loss of fibrinogen is a limiting factor for determining the processing plasma volume. Ion-exchange columns for PA adsorbed bile acids, disconjugated bilirubin, and monoconjugated bilirubin more efficiently compared with delta-bilirubin and unconjugated bilirubin. Pretreatment of the column with heparin reduced the loss of fibrinogen to less than 10%. We applied the BR-350 ion-exchange column in vivo for treatment of three patients with hyperbilirubinemia. After treatment, an alcoholic hepatitis patient with the hepatorenal syndrome (HRS) recovered from acute renal failure. However, in a patient with primary biliary cirrhosis and in a patient with fulminant hepatitis, the decrease of serum bilirubin was transient and no obvious beneficial responses were noted. The capacity and ability of the BR-350 column to adsorb plasma bilirubin was shown sufficient to treat deeply jaundiced patients, because 4 liters of the plasma of a patient with 108 mg/dl of initial total bilirubin concentration was able to be processed continuously without an obvious decrease in bilirubin adsorption capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Conformational analysis of the immunodominant epitopes of the circumsporozoite protein of Plasmodium falciparum and knowlesi

All of the coat proteins of the sporozoite and merozoite stages of Plasmodium, determined to date, contain tandem repeats and most of these contain at least one proline residue. These tandemly repeated segments of the circumsporozite (CS) proteins of P. falciparum and P. knowlesi have been shown to constitute an immunodominant epitope. Antibodies to these peptide segments have been shown to be protective and cause the shedding of the CS protein, known as the CSP reaction. In this study, four synthetic peptides were prepared by solid-phase peptide synthesis. The first peptide corresponds to the tetrapeptide tandem repeat in the CS protein of P. falciparum, repeated eight times, (NANP)8. The second peptide is an analogue of the first in which glycine is substituted for proline, (NANG)8. The third peptide corresponds to the tandem repeat of P. knowlesi, PK(1-24), which is repeated twice (QAQGDGANAGQP)2. The fourth peptide is a tetrapeptide repeat, corresponding to the C-terminal tetrapeptide of PK(1-24) and is repeated eight times, (AGQP)8. It is shown by CD measurements that the presence of proline in these repeats induces an increase in beta-sheet (beta-turn) content in the (NANP)8 peptide relative to the repeat of (NANG)8 and PK(1-24) peptide in aqueous media. The (AGQP)8 peptide has the highest beta-sheet (beta-turn) content of all peptides studied. The Chou-Fasman predictive algorithm indicates a high beta-turn content in the synthetic peptides. It is concluded that this increase in defined structure correlates well with and hence may contribute to the increased antigenicity in these repeats.

[Expression of major histocompatibility complex on human medulloblastoma cells]

Medulloblastoma is one of the most common malignant brain tumors in childhood. These cells are immature bipotential cells that could differentiate into both neuronal and glial cells. The authors established two human medulloblastoma cell lines. One was derived from a 2-year-old girl with cerebellar tumor (designated as ONS-76) and another was from a 9-year-old girl with metastatic tumor in the right frontal lobe (ONS-81). Immunohistochemical studies showed that both cell lines possessed 145 and 200 kDa neurofilament proteins and neuron-specific enolase, without glial fibrillary acidic protein and S-100 protein. It was shown that interferon gamma could enhance or induce the expression of the major histocompatibility complex (MHC) antigens which play a major role in immune response. Also shown for the first time was the expression of MHC class II antigens on human medulloblastoma (ONS-76 and 81) with neuronal differentiation.

Morphological characterization of surface-induced platelet activation

Morphological changes of platelets activated on glass and dimethyldichlorosilane-treated glass were investigated using video microscopy. The platelet morphological changes were quantified by measuring the area and circularity of spreading platelets. In addition, re-organization of cytoskeletal structures of spread platelets was examined. The effects of precoated albumin and fibrinogen on the platelet spreading kinetics were examined as a function of surface protein concentrations. Results showed that platelet shape changes were very sensitive to the surface concentration of precoated proteins. In general, platelets on fibrinogen-precoated surfaces spread fully to a circular shape and developed an extensive inner filamentous zone. In the presence of albumin on the surface, however, platelets could not spread fully and the development of the inner filamentous zone was very poor. For both albumin and fibrinogen, the maximum effects of precoated proteins on platelet shape changes were observed when the surface protein concentration reached the monolayer concentration.

Surgical correction of astigmatism using paired T-incisions

Transverse incision astigmatic keratotomy procedures were performed, combined with radial keratotomy, in 16 eyes for correction of astigmatism and coexisting myopia. We used a transverse incision technique in which T-incisions vertically intersected radial incisions of the steepest corneal meridian. After a mean follow-up period of 10 months with a range of six to 27 months, an average 1.92 diopters of the cylinder was corrected. In comparison with 2.11 diopters of the cylinder corrected at postoperative one day, there was a 22.8% decrease in the effect of astigmatism correction after a postoperative period averaging 10 months.

[Treatment of acute leukemia with "MB-triple V" therapy--a comparative study of "MB-triple V" therapy and B-triple V therapy]

Eleven patients with acute leukemia were treated with MB-triple V therapy consisting of mitoxantrone, behenoyl-arabinoside, etoposide, vincristine and vindesine. In this regimen, the target points were set for WBC count in the peripheral blood (less than 1,500/microliters) and TNC count in the bone marrow (less than 15,000/microliters). In this study, we compared the WBC count in nadir state and the duration until WBC count returned to above 1,000/microliters between 11 patients with MB-triple V therapy and 15 patients with B-triple V therapy in which target points were not set. In particular, the standard distribution of WBC count in nadir state of MB-triple V group was significantly smaller than that of B-triple V group. The number of early deaths in the course of MB-triple V (0/11, 0%) decreased compared with B-triple V group (3/15, 20%). Seven patients of the eleven patients with this regimen achieved CR state (63.6%). Hereafter, further cases are necessary before this combination chemotherapy as a part of the induction therapy is evaluated.

The clinical report on six cases of epikeratoplasty

After the first description of epikeratoplasty for the correction of aphakia by Kaufman in 1980, the application of epikeratoplasty has been extended further to the treatment of keratoconus and high myopia. Six epikeratoplasty for five eyes of high myopia and one eye of keratoconus were performed and followed up for an average of 4.9 months. All cases improved their uncorrected visual acuity, and the preoperative best corrected visual acuity improved or had no change postoperatively except for one case. In the cases of high myopia, the mean preoperative spherical equivalent of -19.4 D was corrected to an average -0.23 D with a range of -1.0 D to +2.5 D postoperatively. In the case of keratoconus, there was a mean decrease in 12.0 D of myopia in terms of the spherical equivalent, and the cornea was flattened by over 8 D in keratometry readings.

[Adoptive immunotherapy in patients with medulloblastoma by LAK cells]

Medulloblastoma is one of the most popular malignant brain tumors in children. It accounts for about 15% of all pediatric brain tumors. Radiochemotherapy has prolonged the 5-year survival rate up to 60-85% for patients with medulloblastoma. But the conventional therapy is not so effective to recurrent cases, especially with meningeal dissemination, and generally fatal. There remains a big problem of the neurotoxicity to infants in a growth process under the whole-neuraxis irradiation and chemotherapy. Aiming to relieve the radiation and antitumor drugs, adoptive immunotherapy is greatly expectant. We have had clinical trials of adoptive immunotherapy for 8 patients with medulloblastoma by lymphokine-activated killer (LAK) cells. They were from 2-9 years in age and had cerebrospinal fluid (CSF) dissemination of the tumors. All patients underwent the whole-neuraxis irradiation and chemotherapy. After they had CSF dissemination, they were submitted to an adoptive transfer of allogeneic LAK cells. LAK cells were induced from peripheral blood lymphocytes (PBL) of their relatives with human recombinant interleukin-2. 3-15 x 10(9) LAK cells were transferred intrathecally in 2-3 months. In 3 of 8 patients, neurological signs were improved and malignant cells had never been detected on CSF cytology after the adoptive immunotherapy. One among these 3 patients showed complete response in 20 months. Thus, this is an attractive treatment for patients with medulloblastoma, especially with CSF dissemination, which cannot be cured by current therapeutic intervention.

Attenuation in the regulation of the pyrBI operon in Escherichia coli. In vivo studies of transcriptional termination

The attenuation model for transcriptional regulation of the Escherichia coli pyrBI operon is based on the assumption that transcription terminates upstream of the structural genes at a rho-independent terminator when cells contain high levels of UTP. When, however, the cells are limited for pyrimidines, the presence of ribosomes translating the short leader peptide is presumed to cause an alteration in the secondary structure of the terminator in a way that allows RNA polymerase to transcribe the entire operon. These two premises of transcriptional regulation were tested by using exonuclease protection assays to map the 3' ends of transcripts extracted from cells containing either ample or depleted concentrations of pyrimidines. The results support the model since 99% of the pyrBI transcripts terminated at the (G + C)-rich region of dyad symmetry upstream of the structural genes when cells were grown in excess uracil. In addition, a significant portion (36%) of the pyrBI transcripts extracted from cells containing reduced pyrimidine concentrations extended past the dyad into the structural genes. This observation correlated with the amounts of aspartate transcarbamoylase synthesized in cells under the various conditions. The mapping technique was also used to determine the position of the 5' ends of the transcripts to measure contributions of two potential start sites (P1 and P2) to the pool of pyrBI transcripts. The results show that under all conditions no more than 3% of the total transcripts had 5' ends corresponding to the upstream promoter, P1. In cells lacking P1 virtually all transcripts from P2 terminated at the (G + C)-rich hairpin when the cellular level of pyrimidines was high. Conversely 57% of the transcripts extended past the terminator when cells were grown in UMP. The S1 nuclease technique also provided a measure of the steady state level of transcripts originating at P2. In cells depleted of pyrimidines there was a 5-10-fold increase in these transcripts depending on the number of copies of pyrBI. This increase, which is independent of attenuation, is caused by a different regulatory mechanism which as yet has not been identified.

Sensitivity-enhanced, common-mode-compensated Mach-Zehnder fiber-optic sensor circuit with electro-optic feedback

A Mach-Zehnder fiber-optic sensor circuit incorporating an optical compensation circuit to reduce errors from common-mode perturbations and electro-optic feedback to enhance measurand sensitivity is proposed and demonstrated. Experimental results show that the phase bias and the feedback constant can be adjusted to yield an operating region with negligible sensitivity to common-mode perturbations and a measurand sensitivity an order of magnitude above that expected from an equivalent conventional Mach-Zehnder sensor, in good agreement with theory.

[A colorimetric method for determination of delta-bilirubin in serum using bilirubin oxidase (Trachyderma tsunodae)]

We developed a colorimetric method to measure delta-Bilirubin in human serum using bilirubin oxidase from Trachyderma tsunodae and diazo reagent. In the first step, bilirubin fractions except for delta-Bilirubin, such as diconjugated, monoconjugated and unconjugated forms, are removed by enzymatic oxidation at pH 8.0 in the presence of sodium salicylate. In the second step, delta-Bilirubin remaining after enzymatic oxidation is determined by the conventional indirect diazo method. The results obtained by this method showed intra-day CV of 2.4%, satisfactory linearity and good correlation (r = 0.93, p less than 0.001) with those obtained by high performance liquid chromatography method. This simple and rapid method was clinical useful for determining the bilirubin fractions in sera of hepatic patients.

[Antitumor efficacy of FK 973 on malignant glioma cells]

FK 973, a new substituted dihydrobenzoxazine, was obtained by chemical modification of a novel antibiotic which was isolated from the fermentation products of streptomyces sandaensis No. 6897. FK 973 had cytotoxic effects against in vitro cultured human and murine glioma cells. The concentration of FK 973 required to inhibit cell growth by 50% was 0.06-5 micrograms/ml, after 2-day exposure of this drug against human glioblastoma (ONS-6, 12, 23, and ONS-12/ACNU), human medulloblastoma (ONS-76, 81), human neuroblastoma (ST), and murine glioblastoma (RSV-M glioma). FK 973 showed antitumor efficacy in the meningeal gliomatosis models by RSV-M glioma cells. The median survival time (MST) of models treated by FK 973 (i.t.) was 30 days. However, the MST of control group was 23 days. In the in vitro neurotoxicity test, FK 973 proved to be slightly more toxic than ACNU and MTX, but it had no crucial problems, compared with ADM.

[Establishment and biological characterization of human medulloblastoma cell lines]

Two cell lines of human medulloblastoma (ONS-76 and ONS-81) were established, and their biological characteristics were investigated. The cell line, ONS-76, was established from a tumor specimens obtained from a large cerebellar tumor of a 2-year-old girl. The pathological diagnosis was a typical medulloblastoma. The other cell line, ONS-81, was derived from a metastatic tumor in right frontal lobe of a 9-year-old girl. The tumor specimens were minced into fragments approximately 1 mm in diameter and cultured in plastic culture flasks in RPMI 1640 medium supplemented with 10% heat-inactivated fetal calf serum (FCS) and 50% patients serum. The cells growing as a monolayer were subcultured in RPMI 1640 supplemented with 10% FCS and initially with L-glutamine, sodium pyruvate, and nonessential amino acid. Microscopically, both cultured cells exhibited various morphological appearances, and this morphological heterogeneity seemed to be specific for medulloblastoma cells. The in vitro population doubling time of ONS-76 and ONS-81 were 18.6 and 19.2 hr, respectively. The ONS-76 and ONS-81 cells formed subcutaneous tumors in nude mice as serial transplantable xenograft, and these tumors had a microscopic appearance similar to that of the original medulloblastoma. Ultrastructurally++, the cultured cells showed primitive, undifferentiated appearance, and no neuronal or glial structures were not seen. Immunohistochemical studies showed that both cells expressed neuron-specific enolase (NSE) and neurofilament protein (NFP 200 K, 145 K), but glial fibrillary acidic protein (GFAP) and S-100 protein were not detected. The NFP immunoreactivities of both cultured cells were demonstrated as abnormal perinuclear deposits.(ABSTRACT TRUNCATED AT 250 WORDS)

Meal-induced peptide tyrosine tyrosine inhibition of pancreatic secretion in the rat

In the present studies we examined the distribution, release, and biological actions of peptide tyrosine tyrosine (PYY) in the rat. The concentration and distribution of PYY was highest in the ileum and colon as determined by both radioimmunoassay of rat tissue extracts and immunocytochemistry. An ultrastructural comparison of rat and dog colonic PYY cells revealed a bipolar distribution of peptide-containing secretory granules in both species. Serum PYY and pancreatic exocrine secretory responses were monitored after presentation of a meal to meal-trained rats (n = 12). A significant increase in PYY concentrations was not observed until 120 min after meal presentation, a delayed response similar to that previously observed in the dog. PYY responses were also observed in rats after perfusion of the intestine at the level of the duodenum and ileum with an 80 mOsm micellar solution of sodium oleate. Duodenal instillations of the fatty acids resulted in a maximum PYY response after 120 min, whereas rats subject to ileal perfusion of fat exhibited maximum PYY release within the first hour. In other experiments, infusion of exogenous PYY at 100 pmol.kg-1.h-1, which reproduced plasma PYY levels observed after a meal and perfusion of the gut with fat, significantly inhibited CCK-stimulated bile pancreatic volume (P less than 0.02), protein (P less than 0.01), and amylase (P less than 0.01) output. These studies demonstrate a bipolar distribution of PYY-containing secretory granules in cells of the jejunal, ileal, and colonic mucosa, and show that PYY is released in response to a meal in amounts sufficient to inhibit cholecystokinin-stimulated pancreatic secretion. Evidence is presented that PYY may mediate the delayed inhibition of pancreatic secretion that is observed in the rat after ingestion of a meal.

Structural features of the acetyl-CoA carboxylase gene: mechanisms for the generation of mRNAs with 5' end heterogeneity

Acetyl-CoA carboxylase [acetyl-CoA:carbondioxide ligase (ADP-forming), EC 6.4.1.2] is the rate-limiting enzyme in the biogenesis of long-chain fatty acids. We have previously characterized five acetyl-CoA carboxylase mRNA species that differ in their 5' untranslated regions but not in the coding region. We have now characterized the exon-intron structure of the genomic DNA that encodes the 5' untranslated region of the mRNA. Generation of different forms of the mRNA is the result of the selective use of two promoters and differential splicing of five different exons. These five exons contain a total of 645 nucleotides and they are scattered over a 50-kilobase-pair genomic DNA region that we have characterized.