Ultrastructure of preimplantation human embryos co-cultured with human ampullary cells

Ova with two pronuclei were co-cultured with established human ampullary cell lines and various stages of preimplantation embryonic development were monitored by Nomarski optics and then assessed by transmission electron microscopy (TEM). Fifteen embryos ranging from the 2-cell stage to blastocyst hatching were examined for normal and abnormal features. Their ultrastructure was similar to that of embryos cultured in Whittingham's T6 medium, reported previously. Seven embryos were evidently morphologically normal and showed good organization of fine structure. Most cellular organelles underwent progressive changes during early development. There was evidence of enhanced embryonic genome activation at the 8-cell stage. Invariably, all embryos had few too many fragments, some internalized, which were later segregated into the blastocoele or found outside the trophoblast of the late morula and blastocysts. Six grossly 'normal' embryos assessed by Nomarski had multiple nuclei of various dimensions, which highlights the subjectivity of embryo assessment in the IVF laboratory. Incomplete incorporation of chromatin into nuclei and formation of micronuclei were evident in some blastomeres. The results are discussed in relation to early embryonic loss, prevalent in IVF. Significant events reported include the detection of centrioles at the 8-cell stage, cavitation of the early blastocyst and the initiation of blastocyst hatching visualized by TEM.

c-myc Oncogene expression in colorectal cancer: its use in prognosis and role in colorectal carcinogenesis

Expression of the c-myc oncogene was studied in 35 cases of colorectal cancer. Elevated expression was found in 46% (16/35) of cases. This elevated c-myc expression was not significantly correlated with tumour stage, tumour size, tumour differentiation or carcinoembryonic antigen gene expression, demonstrating that it is not a useful prognostic indicator in colorectal cancer. The role of c-myc in colorectal carcinogenesis is discussed in the light of these findings and of the recent advances in molecular biology.

Direct detection of Neisseria gonorrhoeae with monoclonal antibodies characterized by serotyping reagents

A panel of monoclonal antibodies (MAbs) directed to outer membrane protein I were generated with the ultimate aim of detecting Neisseria gonorrhoeae in patient samples by a direct immunofluorescence (IF) test. In an initial evaluation of the sensitivity of these reagents, a cocktail of six IF MAbs recognized 491 (91%) of 540 gonococci isolates from several centers in Sydney, Australia. IF MAbs designated 185 and 228 recognized serovars of WI serogroup and IF MAbs 208, 210, and 312 recognized serovars of WII/III serogroup. IF MAb 198 recognized serovars within both serogroups. Three additional IF MAbs, designated 322, 323, and 330, were then generated by using strains which failed to react with the original MAb cocktail and which belonged to particular serovars. The new cocktail of nine IF MAbs recognized 96% of the gonococcal isolates, which incidentally contained representatives of serovars shown to have a worldwide distribution in previous studies. Although subtle differences were apparent in the reaction patterns found with coagglutination (serotyping) and IF, there nonetheless seems to be merit in the approach of continually evaluating the sensitivity of diagnostic reagents such as MAbs. This is especially true with an organism such as N. gonorrhoeae, which has the capacity to regularly alter the antigenic structure of its outer membrane proteins.

Effect of sucralfate and cimetidine on duodenal ulcer-associated antral gastritis and Campylobacter pylori

The course of gastritis and Campylobacter pylori was studied in a single-blind randomized trial comparing cimetidine 200 mg three times a day and 400 mg at night and sucralfate 1 g four times a day orally for four weeks in 140 patients with proved duodenal ulcer. At least two antral biopsies were performed during endoscopy before entry and at the end of four weeks. The activity and the degree of chronic inflammation, as assessed histologically by the degree of infiltration of, respectively, polymorphs and chronic inflammatory cells, were graded blindly by two pathologists as nil, mild, moderate, or severe. The density of C. pylori, as assessed after Warthin-Starry stain, was similarly graded. Ulcer-healing rates were comparable in the cimetidine (73.2 percent) and sucralfate (79.7 percent) groups. Improvement of the activity of gastritis occurred significantly (p less than 0.05) more frequently in the sucralfate (33.3 percent) than in the cimetidine group (18.3 percent), and remained so (p less than 0.05) when only patients with healed ulcer were compared. The density of C. pylori decreased significantly in the sucralfate group after treatment (p less than 0.01) but not in the cimetidine group. The 12-month ulcer relapse rates were significantly (p less than 0.05) lower by life-table analysis in patients healed with sucralfate than in those healed with cimetidine and were unaffected by either the density of Campylobacter in either group or the improvement of the gastritis. It is concluded that sucralfate improves duodenal ulcer-associated antral gastritis and decreases the density of C. pylori, and that factors other than bacterial density and antral gastritis may be responsible for the advantage of sucralfate over cimetidine in ulcer relapse.

Natural history of Campylobacter pylori in duodenal ulceration treated with an H2-antagonist

Campylobacter pylori has been associated closely with active antral gastritis and duodenal ulcer but its pathogenetic role remains uncertain. The present longitudinal study examined, prospectively, the endoscopic antral biopsies of 45 patients with duodenal ulceration, taken before and after healing of the duodenal ulcer, during remission and at relapse. The biopsies were examined for the activity and degree of chronic inflammation of the gastritis and for the occurrence and density of C. pylori by Warthin-Starry stain. Before treatment the frequency of chronic active antral gastritis was 100% and the occurrence of C. pylori was 97%. Compared with the pre-treatment state, there was no significant change in either the frequency and severity of antral gastritis, or in the occurrence and density of the bacteria in the antral mucosa at the time the duodenal ulcer healed, during remission, or at relapse. The occurrence of the bacteria was significantly more frequent during remission, than at the time when the ulcer had healed initially (P less than 0.05). These results suggest that the bacterium may not play an important pathogenetic role in ulcer healing and relapse, when patients are managed using an H2-blocker.

Giemsa staining for cysts and trophozoites of Pneumocystis carinii

Although Giemsa staining has been routinely used for the detection of trophozoites and intracystic bodies in smears of bronchoalveolar lavage fluid (BAL) from patients with Pneumocystis carinii pneumonia, it does not normally stain the cyst wall. For detection of the cysts other stains such as toluidine Blue 'O' and methenamine silver must be used as well. Sulphation of smears before staining with Giemsa allows cysts to be visualised, thus enabling a single stain to be used to show all the stages of BAL or sputum, which is particularly useful, considering the increase in the prevalence of P carinii pneumonia in conjunction with the spread of AIDS.

The effects of ultrarapid freezing on meiotic and mitotic spindles of mouse oocytes and embryos

Preovulatory mouse oocytes and 2-cell embryos were frozen with dimethyl sulfoxide and propanediol by an ultrarapid method. The survival of frozen oocytes was low (33-34%) compared to that of 2-cell embryos (78-79%) with either cryoprotectant. Development to blastocysts after postthaw culture was about 7-15% for oocytes and 79-80% for the embryos. Ultrarapid freezing preserves cell structure quite well as revealed by electron microscopy, but meiotic oocytes and late 2-cell embryos undergoing mitosis showed evidence of spindle disorganization involving loss or clumping of microtubules resulting in some scattering of chromosomes. Embryos developed from frozen eggs showed clear evidence of micronuclear formation and incomplete incorporation of chromosomal material into main nuclei. These experiments confirm our observations on freezing of human oocytes and show that spindle microtubules are sensitive to freeze-thawing and that cryopreservation could cause chromosomal aberrations during early development. A cautious approach to the introduction of oocyte freezing in human in vitro fertilization (IVF) programs is advocated.

Pancreatic cancer mucin from xenografts of SW1990 cells: isolation, characterization, and comparison to colon cancer mucin

Mucin has been purified from nude mouse xenografts of SW1990 human pancreatic cancer cells. The mucin was eluted at the void volume of Sepharose CL-4B and was of density greater than 1.3 in CsCl gradients. The isolated mucin had a high content of threonine, serine, and proline, with 31% of the amino acid residues O-glycosylated. The average oligosaccharide composition was NeuAc1.8Fuc0.7Gal2.0GlcNAc1.7GalNAc1.4. Polyclonal rabbit antibodies prepared against the purified mucin recognized primarily mucin polypeptide, and there was extensive immunological cross-reaction between SW1990 pancreatic cancer mucin and LS174T colon cancer mucin. However, using carbohydrate-specific monoclonal antibodies, the two mucins were found to differ. SW1990 mucin had more Lewis, sialyl Lewis, and sialyl Lewis activity, while the colon cancer mucin had more sialyl T antigen. Since pancreatic mucins, whether from normal pancreas or pancreatic cancer, have not previously been well characterized, the availability of SW1990 pancreatic cancer mucin may be useful as a model for studying the expressing of organ-specific or cancer-associated antigens.

Delayed pelvic abscess eight years after generalized peritonitis

Recently, during a locally severe epidemic of gastroenteritis, a young woman presented, with the symptoms prevalent in her community, harboring an intraabdominal abscess. The case is presented along with a discussion of unusual and delayed presentations of abscesses in the literature. Early diagnosis is imperative because of the very significant morbidity and mortality accompanying delayed treatment.

Fine structure of early human embryos frozen with 1,2 propanediol

Previous studies by a French group (Fertil Steril 44:645-651, 1985) have shown that two- to eight-cell human embryos can survive slow freeze-thawing with propanediol in a biological freezer. These embryos were assessed for morphological appearance by phase-contrast microscopy. We assessed the structure of 25 frozen-thawed one- to 12-cell embryos, obtained from our in vitro fertilization (IVF) and GIFT programmes, by phase-contrast and electron microscopy, using the same method of cryopreservation. One-fourth of the embryos examined had all cells intact, and more than one-half the embryos had over 50% of their cells well preserved. Some of these embryos had unequal blastomeres and cytoplasmic fragments. Ultrastructural assessment revealed good preservation of fine structure in the intact blastomeres of all embryos and maintenance of cell-to-cell contacts. Most cytoplasmic organelles, cell membranes, and nuclei were well preserved compared to nonfrozen controls. The cells that were cryoinjured showed varying degrees of disorganization of the cell membrane, cytosol, and cellular membranes, including swelling and disruption of the nuclear envelope. Disruption of the zona was somewhat rare. Small cytoplasmic fragments were less prone to cryoinjury than blastomeres. The use of propanediol for embryo cryopreservation seems to be feasible; frozen embryos with more than 50% cells intact have produced 10 pregnancies after embryo transfer (Fertil Steril 46:268-272, 1986). Replacement of 17 frozen embryos in seven patients has resulted in a twin pregnancy in Singapore. However, the effects of freezing on the mitotic spindles of embryonic cells need to be investigated further.

Persistence of Campylobacter pyloridis despite healing of duodenal ulcer and improvement of accompanying duodenitis and gastritis

Campylobacter pyloridis has been associated with antral gastritis and duodenal ulcer. To study the pathogenetic role of these organisms in duodenal ulcer, endoscopic biopsies, two from the first part of duodenum, four from antrum, and four from body and fundus, were taken before and after four weeks of cimetidine treatment (1.2 g/day) from 67 patients with active duodenal ulcer. The biopsies were examined for the presence and severity of any inflammation by two independent pathologists in the absence of any clinical information and for the occurrence and density of Campylobacter pyloridis by culture and Warthin-Starry stain. Before treatment, inflammation was present in 71.1, 100, and 25.8%, while the organisms were present in 34.3, 91.0, and 79.1% of the duodenal, antral, and fundal biopsies, respectively. With complete healing of duodenal ulcer, inflammation was present in 48.9, 98.2, and 30.2%, while the organisms were present in 25, 76.7, and 63.3% of the respective mucosae. With ulcer healing, duodenitis became significantly milder (P less than 0.05). With improvement of gastritis and duodenitis, there was no significant change in the occurrence and density of Campylobacter pyloridis. These findings indicate that healing of duodenal ulcer is not influenced by the presence of Campylobacter pyloridis, which is frequently found in the gastroduodenal mucosa of patients with duodenal ulcer, but does not appear to be associated with mucosal inflammation except in the antrum.

Quantitative determination of porphyrins, their precursors and zinc protoporphyrin in whole blood and dried blood by high-performance liquid chromatography with fluorimetric detection

Methods for the determination of porphyrins, delta-aminolevulinic acid (ALA), porphobilinogen (PBG) and zinc protoporphyrin of heme biosynthesis in whole blood and dried blood are described. Erythrocyte porphyrins and the precursors ALA and PBG were extracted from whole blood (50 microliter) with 0.3 ml of methanol and 1.5 M hydrochloric acid (2:1, v/v). Zinc protoporphyrin was extracted with an acetone-pyridine-Sterox solution. Other major interfering metabolites were removed by centrifugation. An aliquot of the supernatant was injected onto the reversed-phase C18 column for detection of porphyrins with excitation wavelength at 405 nm and emission wavelength at 630 nm. The mobile phase was 0.1 M phosphate-methanol-tetrahydrofuran (18:30:16, v/v/v), pH 5.38. The ALA and PBG were derivatized with o-phthalaldehyde before injection. The detection excitation wavelength occurred at 330 nm and the emission wavelength at 418 nm. The mobile phase was 0.1 M phosphate-methanol (7.5:5), pH 3.38. For the dried blood specimen of filter paper, two 0.64-cm discs punched out from the blood-impregnated filter paper were placed in a test tube containing 200 microliter of 0.9% saline for 60 min or longer at room temperature and then treated as whole blood.

Chronic antral gastritis in duodenal ulcer. Natural history and treatment with prostaglandin E1

The natural history of chronic antral gastritis in relation to the healing of duodenal ulcer and its response to treatment, if any, are unknown. We performed a double-blind controlled trial using an oral prostaglandin E1, misoprostol, in 229 patients with active duodenal ulcer randomized to receive placebo (n = 76), misoprostol 200 micrograms (n = 77), or misoprostol 300 micrograms (n = 76), q.i.d. orally. Healing of duodenal ulcer was assessed biweekly up to 12 wk by endoscopy, during which procedures at least two antral and two fundal biopsy specimens were taken. The activity and the degree of chronic inflammation of gastritis, as assessed histologically by the infiltration of polymorphs and chronic inflammatory cells, respectively, was graded blindly by two pathologists as nil, mild, moderate, or severe. Before treatment, 99% of patients had chronic antral gastritis and 1.5% had chronic fundal gastritis. In the placebo group, healed duodenal ulcer was associated with significantly (p less than 0.01, life table analysis) higher incidence of improvement of the activity of the antral gastritis (nil or mild as endpoint) than unhealed ulcer (30% vs. 4% at week 8). Irrespective of whether duodenal ulcer was healed or unhealed, significantly (p less than 0.01) more patients on misoprostol (50% at week 8) showed improvement (nil or mild as endpoint) than the placebo group. The degree of chronic inflammation of the antral gastritis showed similar significant changes in favor of misoprostol. Smoking and alcohol intake had no significant effect on the improvement of chronic antral gastritis. In conclusion, healing of duodenal ulcer was associated with improvement of the activity of chronic antral gastritis, which, as shown for the first time, could be further enhanced by a therapeutic agent--prostaglandin E1.

Liver disease in asymptomatic hepatitis B surface antigen carriers

Fifty-five Chinese healthy asymptomatic Hepatitis Bs Antigen carriers, 49 males and 6 females, were studied over a six year period, 1978 to 1984. Seventeen patients (30.9%) had normal transaminases, and 38 patients (69.1%) had fluctuating levels of transaminases throughout the period of study. 83.6% of patients were below 40 years, and mean age was 29.5 years (range 18 to 49 years). Twenty three patients (41.8%) had liver biopsy, and a spectrum of chronic liver diseases was seen, with Chronic Lobular Hepatitis (CLH) and Chronic Persistent Hepatitis (CPH) being the commonest. Six patients (26.1%) had normal histology, seven patients (30.4%) had CLH, seven patients (30.4%) had CPH, two patients (8.7%) had Chronic Active Hepatitis (CAH), and one patient (4.4%) with Active Cirrhosis (AC). An attempt to correlate the severity of histological changes with the levels of transaminases at the time of biopsy failed to show any definite correlation. However, three patients with transaminases of more than four times normal had severe liver diseases (2 CAH and 1 AC).

Liver disease in blood donors with raised transaminases

1000 consecutive blood donors had their liver functions studied. 110 donors (11%) were found to have raised ALT of more than twice normal levels. 29 donors had liver biopsies done. Histologically 23 had fatty change, 5 had chronic persistent hepatitis and 1 had liver cirrhosis. Fourteen out of the 23 donors with fatty change also had hypercholesterolemia and hypertriglyceridemia. Viral serology of the 110 donors showed that 3 donors were HBsAg positive, 5 donors were Anti-HAV (IgM) positive and 20 donors were Anti-HBc (IgM) positive. Majority of donors with raised ALT had fatty liver on biopsy with only 6 donors having significant findings of chronic persistent hepatitis and cirrhosis. Serologically, most of the donors (74.5%) with raised ALT had no markers of Hepatitis A, Hepatitis B, CMV or EBV. An interesting finding is the high incidence (18%) of positive, Anti HBc (IgM) in donors with raised ALT.

Detection of delta-aminolevulinic acid, porphobilinogen and porphyrins related to heme biosynthesis by high-performance liquid chromatography

Two new high-performance liquid chromatographic methods are described for the quantitative determination of porphyrins and their precursors. In our method, sub-nanomole quantities of porphyrins, delta-aminolevulinic acid and porphobilinogen derivatized with ophthalaldehyde were injected onto a C18 reversed-phase column and eluted with 0.1 M monobasic sodium phosphate-methanol-tetrahydrofuran (4:6:3) and detected with a spectrofluorometer. A second reversed-phase system using methanol-tetrahydrofuran-22 mM acetate buffer (15:6:11) was also developed.

Recovery of malignant tumor cells from the right atrium during hepatic resection for hepatocellular carcinoma

Tumor cells were recovered from the right atrium in three of five patients during hepatic resection for hepatocellular carcinoma. Mechanical factors during blunt mobilization and rotation of the hepatic tumor appeared to be responsible for tumor dislodgement into the venous circulation. Tumor embolization to the lungs may be one of the important reasons for the poor results of surgery in this disease. Two possible technical and therapeutic modifications are suggested to prevent or neutralize this phenomenon.

Immunoglobulin M and G histoplasmal antibody response in histoplasmosis

Radioimmunoassays for IgM and IgG histoplasmal antibodies were developed and proved to be specific for their respective immunoglobulin classes, sensitive, and reproducible. Elevated IgM antibodies were detected in 59.8% of patients with histoplasmosis and 7.9% of control subjects. Elevated IgG antibodies occurred in 80.4% of patients with histoplasmosis but in only 12.9% of control subjects. Radioimmunoassay was nearly twice as sensitive as complement fixation for identifying patients with mild, presumably asymptomatic, infection. Of 13 patients with serologic follow-up at least 1 yr later, elevated IgM antibodies cleared, whereas IgG antibodies persisted in 7. In an epidemiologic investigation of a recurrent histoplasmosis outbreak, only the radioimmunoassay was able to prove the hypothesis that construction for a swimming complex was the source of exposure. These assays promise to be useful for clinical and epidemiologic investigations.

Pachydermoperiostosis, hypertrophic gastropathy, and peptic ulcer

Two brothers with pachydermoperiostosis, an autosomal dominant syndrome characterized by digital clubbing, periosteal new bone formation, coarse facial features with thick, furrowed, and oily skin, presented in their twenties with severe complicated duodenal ulcer disease requiring multiple operations. Their father and one paternal uncle also had pachydermoperiostosis and a past history of ulcer dyspepsia. The mother, one sister, two maternal aunts, and one other paternal uncle were healthy. Both brothers had giant hypertrophic gastritis (Ménétrier's disease). Their pentagastrin-stimulated acid output and fasting and meal-stimulated serum gastrin levels were normal, but their serum pepsinogen I and II levels were markedly elevated. The father had hypochlorhydria and a low serum pepsinogen I/II ratio, suggesting atrophic gastritis. This family study raises the possibility that pachydermoperiostosis, hypertrophic gastropathy, and peptic ulcer may be genetically related.

Prednisolone in HBsAg-positive chronic active hepatitis: histologic evaluation in a controlled prospective study

To study the value of corticosteroids in HBsAg-positive chronic active hepatitis, 18 pairs of liver histology comprising 36 liver biopsies from a prospective, randomized, controlled trial were evaluated. The median interval between the initial and follow-up histology was 8 1/2 months in 8 patients given prednisolone and 8 1/4 months in 10 patients given placebo tablets. Following medication, there was significantly greater erosion of the limiting plate in the prednisolone group (p = 0.039) accompanied by a larger quantity of HBsAg (p = 0.045) and HBcAg (p = 0.006) in the liver. We conclude that prednisolone causes immunosuppression permitting enhanced viral multiplication and leads to increased erosion of the limiting plate. Our result also indicates that progression to cirrhosis is unhalted by prednisolone therapy. The histologic findings support clinico-biochemical conclusion that the use of prednisolone is deleterious to patients with HBsAg-positive chronic active hepatitis.

Mucoepidermoid carcinoma of the bile duct

Three patients with mucoepidermoid carcinoma of the bile duct are described. In two patients the tumor arose from the common hepatic duct. Mucoepidermoid carcinoma of the extrahepatic bile duct has not been previously reported. The clinical features and pathologic behavior of this rare type of tumor are similar to the usual biliary adenocarcinoma. The coexistence of Clonorchis sinensis infestation and primary pyogenic cholangitis raises the possibility of an etiologic association.

Selective coating of gastric ulcer by tripotassium dicitrato bismuthate in the rat

Controlled clinical trials have shown that tripotassium dicitrato bismuthate healed duodenal and gastric ulcers significantly better than placebo. One mechanism suggested is that it forms a protective coat at the ulcer base. We studied this coating action in rats with chronic gastric ulcers produced by a standardized technique for mucosal wounding at the fundoantral junction. Bismuth was identified by histochemical staining using Castel's reagent, the specificity of which was verified in vitro against 13 other metallic compounds and chemicals. Our results showed that tripotassium dicitrato bismuthate had a coating affinity for the ulcer base, but not for the adjacent normal mucosa. All rats treated with tripotassium dicitrato bismuthate 1, 2, 4, and 6 h previously, but not the control rats treated with water or those treated with four other bismuth compounds, manifested a layer of bismuth that coated the ulcer base. Light and electron microscopy of the tripotassium dicitrato bismuthate-treated ulcers--but not their controls-revealed an abundance of macrophages, which had ingested the bismuth. This unique bismuth coat may insulate the ulcer base from acid-pepsin digestion, while the influx of macrophages may expedite reparative processes.

An autopsy study of hepatocellular carcinoma in Hong Kong

Two hundred and eighty-seven autopsy cases of hepatocellular carcinoma (HCC) in Chinese were reviewed. The analyses included histological study of the tumour and of the non-cancerous liver tissue, the cause of death and metastases. Bleeding of oesophageal varices was more frequent but rupture of tumour less common in cases associated with cirrhosis than in those without cirrhosis. There was a significantly higher incidence of bilobar involvement by tumour in the clear cell type of HCC and in cases unassociated with cirrhosis compared to other histological types of HCC and HCC with cirrhosis, possibly because of longer survival of the former groups. A strong association was found between cirrhosis and hepatic fibrosis with HCC and hepatitis B surface antigen (HBsAg), suggesting an oncogenic effect of chronic persistent hepatitis B virus (HBV) infection on hepatocytes.

Glenn shunt: long-term results and current role in congenital heart operations

Fifty cyanotic patients (aged 2 days to 22 years) underwent Glenn shunts for tricuspid atresia and other cyanotic heart defects. Thirteen of 15 operative deaths occurred in infants less than 4 months old, and only 1 death has occurred in the last 9 years. Results were poor in patients with Ebstein's anomaly, truncus arteriosus, transposition of the great vessels, and complex defects other than tricuspid atresia and univentricular heart. Of the 35 patients followed from 0.9 to 14.8 years, 12 were followed for more than 10 years. None of the 11 late deaths could be attributed to complications of the shunt. Minimal evidence of intrapulmonary shunting was found by angiography, pulmonary venous oximetry, or radioisotopic studies. Late deterioration due to venous collaterals and decreased flow to the opposite lung necessitated Blalock-Taussig shunts in 6 and Fontan procedures in 10. All survived the Fontan procedures with minimal morbidity. These data support the concept that Glenn shunts do not necessarily result in pulmonary abnormalities and may be indicated as a staged procedure in a few selected patients prior to a Fontan procedure.

Bilateral ureteric obstruction secondary to metastatic carcinoma of the oesophagus

Ureteric involvement by metastatic tumour from squamous cell carcinoma of the oesophagus has not yet been described, and we report here a case of this condition.

Hepatotrophic effects of insulin on glucose, glycogen, and adenine nucleotides in hepatocytes isolated from fed adult rats

In vivo observations have suggested that there is an hepatotrophic effect of insulin. By contrast, subsequent in vitro work, using the isolated perfused liver system, showed no effect or indeterminate effects of insulin on the transport of glucose into the hepatocyte. However because this system may not have endured long enough to show such an influence we explored the transport of glucose using a 48-h suspension culture of hepatocytes isolated from young adult fed rats, the suspension being infused continuously with insulin at a rate approximating the maximum entering portal blood in the fed state. (In a separate study phloridzin was added after 2 h of incubation.) DNA, intracellular glucose and its inward transport, glycogen, and the adenine nucleotides were measured at intervals. By comparison with control or untreated cells, insulin-treated cells showed significantly more DNA and intracellular glucose, and the differences were abolished by phloridzin. Glucose transport rates fell to low values in untreated controls and still lower with insulin plus phloridzin, but the initial rate was maintained to the end (48 h) by insulin alone. Results for glycogen were similar to those for intracellular glucose. There was a close correlation (r = 0.96) between these two. The total adenine nucleotide pool and the concentration of ATP were maintained for about 24 h and fell to half their initial values by 48 h. Insulin had increased these concentrations significantly by 6 h. Although concentrations of ADP and AMP decreased gradually in all groups of cells, insulin enhanced the level of ADP by 12 h but had no measurable effect on that of AMP. The energy charge increased slightly throughout incubation but more so (by 6 h) in the presence of insulin. In conclusion the data support the concept that in the longer term (greater than 12 h) insulin in the portal circulation maintains the characteristic free permeability of the hepatocyte to glucose and this permits a variety of effects related to glucose entry into the hepatocyte.

Recovery of quenched radioactivity from thin-layer chromatographic plates. An improved assay for cGMP phosphodiesterase in Myxococcus xanthus

Ammonium bicarbonate was found useful in extracting a variety of radiolabeled compounds from thin-layer chromatographic plates. The technique significantly increased the sensitivity of the assay for cyclic nucleotide phosphodiesterases. This method was used to show unequivocally, the presence of cGMP phosphodiesterase in vegetative cells of Myxococcus xanthus.

Multiple primary germinomas (ectopic pinealoma) of the brain

A case of primary multiple germinomas occurring in the corpus callosum and thalamus with excellent outcome following biopsy and irradiation is reported. The pathogenesis of intracranial germinoma is briefly discussed.

Hepatotrophic effects of insulin on glucose, glycogen, and adenine nucleotides in hepatocytes isolated from fasted adult rats

Previous evidence that portal blood insulin is an hepatotrophic factor led to this study of its effect on hepatocytes, isolated from fasted rats, in suspension culture. Control hepatocytes (C), noninsulin-treated, and those infused continuously at low (LI) and high (HI) levels of insulin were compared concurrently with regard to their survival, glucose transport, and intracellular concentrations of glucose, glycogen, and adenine nucleotides, over a 48-hr period of incubation. Low insulin was adjudged to be comparable to portal insulin concentrations in fasted animals and HI to those in fed animals. All hepatocytes had been depleted of glucose, glycogen, and adenine nucleotides at the start of the study by prior fasting of the rat. For the first 6 hr of culture, there was little difference between C, LI, and HI with reference to the above parameters. In contrast, after 48 hr of incubation, cell survival, as judged by the DNA content, was signficiantly lower in C compared with LI and HI. The transport of 3--0-[methyl-3H] D-glucose was also significantly lower in C compared with LI and HI. The higher uptakes in both LI and HI were reduced by phloridzin, which had little effect on C. Correspondingly, the intracellular glucose concentrations in C were significantly lower than the extracellular glucose concentrations in contrast to those in LI and HI, which were comparable. For intracellular concentrations of glycogen and adenine nucleotides, the results of LI and HI were amalgamated as they were not significantly different from each other at 48 hr. Upon analysis, glycogen values were significantly higher for insulin-treated cells. Similarly, the total adenine nucleotide p-ol (ATP + ADP + AMP) also was clearly higher in HI + LI than in C. These results indicate that contrary to findings in studies with the perfused liver that have been of a short-term nature, insulin is necessary in the longer term (greater than 12 hr) for maintaining the transport of glucose into hepatocytes; thereby insulin promotes the maintenance of intracellular glucose, glycogen, and adenine nucleotide concentrations, and also enhances cell survival.

Demonstration of positive chemotaxis to cyclic GMP and 5'-AMP in Myxococcus xanthus by means of a simple apparatus for generating practically stable concentration gradients

A simple apparatus is described for the generation of stable concentration gradients in agar for the study of chemotaxis in gliding bacteria. Myxococcus xanthus was found to be positively chemotactic for guanosine 3′:5′-cyclic monophosphate (cGMP) and adenosine-5′-monophosphate (AMP).

Cyclic nucleotides, cyclic nucleotide phosphodiesterase, and development in Myxococcus xanthus

Exogenous cyclic nucleotide phosphodiesterase (PD) accelerated fruiting body (FB) formation and increased territory size of aggregates in Myxococcus xanthus. Both guanosine 3'5'-monophosphate (cGMP) and guanosine 5'-monophosphate (GMP) were antagonistic to the PD effect. Adenosine 3'5'-monophosphate (cAMP) increases FB numbers twofold in the absence but not in the presence of PD. PD induction is not affected by methionine or isoleucine, which inhibit, or by threonine, which stimulates, FB formation. There is an increase and subsequent decrease in cAMP levels during early glycerol-induced microcyst development but 10 mM theophylline or caffeine not only inhibited microcyst development but induced germination in the presence of glycerol. On the basis of these results and the reports of other investigators a tentative model is proposed based on a dual role for cyclic nucleotides in the development in M. xanthus.

Bile acid synthesis in isolated rat hepatocytes

Normal adult rat hepatocytes were incubated for 48h and the concentration of total and individual bile acids in homogenized samples of the culture was measured at intervals during the incubation, using radiogas chromatography and isotope derivative assay. The net increase in bile acids over the value observed at the start of the culture was taken as synthesis. The results showed that bile acid synthesis was linear up to 24h of incubation, at a rate of 20nmol/g hepatocytes per hour, and that 85% of the newly synthesized bile acid was cholic acid. The bile acid synthesized was mainly conjugated with taurine. These results suggest that isolated hepatocytes cultured in the way described could be a useful in vitro model for the study of bile acid synthesis.

Comparison of dihydrofolate reductases from trimethoprim- and sulfonamide-resistant strains of Neisseria gonorrhoeae

The dihydrofolate reductases were purified from Neisseria gonorrhoeae strains CDC 9 and 7134, for which MICs of trimethoprim differ twofold and MICs of sulfadiazine differ sixtyfold. Although affinities of the dihydropteroate synthetases from the two strains for sulfonamide were known to differ markedly, no conclusive difference in the extents of binding of trimethoprim by the dihydrofolate reductases from these organisms could be demonstrated. Thus, it was concluded that permeability of the cell envelope or increased production of dihydrofolate reductase may be an important factor among strains of N. gonorrhoeae that have low- and middle-range resistance to trimethoprim.

Effects of hormones on the synthesis of alpha 1 (acute-phase) glycoprotein in isolated rat hepatocytes

Hormone effects on the synthesis of alpha(1) (acute-phase) glycoprotein and of albumin by isolated rat hepatocytes in suspension were examined. Insulin, glucagon, cortisol, somatotropin (bovine growth hormone) and tri-iodothyronine were added to achieve physiological concentrations in the medium [Jeejeebhoy, Ho, Greenberg, Phillips, Bruce-Robertson & Sodtke (1975) Biochem. J.146, 141-155]. After periodic additions, there were increases (compared with values for non-hormone-treated suspensions) in the concurrent absolute syntheses of alpha(1) (acute-phase) glycoprotein and of albumin. Trends were detectable after 24h, and significant increases were demonstrated after 48h of incubation (219 and 119% respectively of control values). Manipulation of hormones, by omission from the mixture or by addition of only one or two hormones in various combinations, indicated that for alpha(1) (acute-phase) glycoprotein (which may be representative of some other acute-phase proteins), cortisol was one of the most important hormones involved in the stimulation of synthesis, with glucagon enhancing the effect of cortisol but not being stimulatory by itself. Addition of actinomycin D inhibited this stimulation, suggesting that cortisol might have acted through promotion of RNA synthesis. For albumin, cortisol alone did not stimulate synthesis, but its absence from a hormone mixture significantly decreased synthesis compared with that observed with the complete hormone mixture. Our findings support the possibility that following tissue injury, synthesis of alpha(1) (acute-phase) glycoprotein may be stimulated by the hormonal response to this injury (which response includes elevated blood concentrations of cortisol and glucagon).

Synthesis of hemopexin with and without hormonal supplementation in rat hepatocyte suspensions: comparison with that of albumin and of fibrinogen

The rate of hemopexin synthesis in adult rat hepatocyte suspension (0.17 +/- 0.019 (6)) (mean +/- SEM (n) mg/g hepatocytes per hour) was found to be linear for 48 h. By contrast, the rate of synthesis of albumin and fibrinogen was close to linear for only 12 h after which it continued at a diminished rate. Supplementation of the incubation medium with insulin, cortisol, glucagon, triiodothyronine, and growth hormone affected no significant increase in the synthesis rate of hemopexin but by contrast did do so in that of albumin (22%) and of fibrinogen (123%) (although not to the point of causing these last to become linear). The pattern of hemopexin synthesis and its response to hormones is clearly different from that observed with other plasma proteins studied in this hepatocyte system. Hempoexin synthesis appeared to be at its maximum and to be independent of hormone supplementation, and it was continuing linearly at a time when the synthesis of other plasma proteins was falling.

Albumin, fibrinogen and transferrin synthesis in isolated rat hepatocyte suspensions. A model for the study of plasma protein synthesis

A system using hepatocyte suspensions in vitro was developed for studying the synthesis of albumin, fibrinogen and transferrin. Conditions for optimum survival of the hepatocyte and for synthesis of these plasma proteins were defined for this system. These conditions included the use of horse serum (17.5 percent, v/v, heat-inactivated), an enriched medium (Waymouth's MB 752/1), an O2 tension of between 18.7 times 10(3) and 26.7 times 10(3) Pa and constant stirring. Albumin, fibrinogen and transferrin synthesis rates were obtained of 0.32 p 0.094(10), 0.12 p 0.030(11) and 0.097 p 0.017(10) [mean p S.D. (n)]mg/h per g of hepatocytes respectively. These rates were maintained for the first 12h of study and synthesis continued at a diminished rate up to 48h. The synthesis of albumin was decreased in a medium containing less amino acids and glucose, but that of fibrinogen was substantially unaffected. ATP concentrations up to 12h and RNA/DNA ratios up to 24h were comparable with values in vivo. The ability to study cells up to 48h permitted us to find that the addition of a mixture of hormones consisting of glucagon, cortisol, tri-iodothyronine and growth hormone enhanced fibrinogen synthesis. Addition of insulin to the above mixture resulted in increased synthesis for albumin and transferrin but not for fibrinogen.