Diagnosis of nasopharyngeal carcinoma by DNA amplification of tissue obtained by fine-needle aspiration

BACKGROUND

In nasopharyngeal carcinoma the primary lesion is often difficult to find. Metastatic lesions occur frequently but are difficult to distinguish from other head and neck tumors. The viral genome of the Epstein-Barr virus (EBV) can be identified in the cells of this carcinoma.

METHODS

We used the polymerase chain reaction (PCR) to test for the presence of EBV genomes in 15 samples of metastatic squamous-cell carcinoma of the neck obtained by fine-needle aspiration and in 26 samples obtained by biopsy of lymph nodes. For controls we used disease-free lymph nodes from 10 patients with various head and neck tumors, tonsillar tissue from 46 subjects, blood from 59 EBV-seropositive blood donors, and mononuclear cells from 8 patients with fatal lymphoproliferative lesions.

RESULTS

Of the 41 malignant lesions examined, only the nine nasopharyngeal carcinomas (one primary lesion and eight metastases) contained EBV genomes. None of the 20 nodes with other types of cancer, the 10 disease-free nodes, or any of the 105 normal control samples contained detectable EBV. In two patients with suspected metastases from occult primary tumors, the presence of EBV was predictive of nasopharyngeal carcinoma; in both cases overt nasopharyngeal carcinoma developed within one year.

CONCLUSIONS

In patients with suspected nasopharyngeal carcinoma, fine-needle aspiration can provide tissue for diagnosis by DNA amplification of EBV genomes. The presence of EBV in metastases from an occult primary tumor is predictive of the development of overt nasopharyngeal carcinoma.

Comparative bioavailability of two flurbiprofen products: stereospecific versus conventional approach

In this randomized, crossover study comparing the bioavailability of a film-coated (Ansaid) with a sugar-coated (Froben) 100 mg tablets of racemic flurbiprofen in 23 healthy young men, no significant differences were found for Cmax, tmax or AUC, using a nonstereoisomeric assay for flurbiprofen. Minor differences in the appearance of flurbiprofen in serum during the first 30-min post-dosing period were noted, with Ansaid appearing earlier than Froben. These differences likely reflect dissolution rate dissimilarity between the two products. Stereospecific determinations demonstrate a small (7.8 per cent) but significant difference in AUC of the active S-configuration (Froben greater than Ansaid). No significant differences between Ansaid and Froben were found for tmax or Cmax for the S-flurbiprofen. In bioequivalency studies of chiral drugs, stereospecific approaches provide a more accurate assessment of products.

Distribution of two forms of somatostatin and peptides belonging to the pancreatic polypeptide family in tissues of larval lampreys, Petromyzon marinus L.: an immunohistochemical study

Immunohistochemistry on tissues of larval lampreys, Petromyzon marinus L., was used to determine the distribution of invariant somatostatin-14 (SST-14) and lamprey somatostatin-34 (SST-34) in the brain while antisera against porcine peptide tyrosine tyrosine (PYY), human neuropeptide Y (NPY), anglerfish peptide YG (aPY), salmon glucagon-like peptide (GLP), SST-14, and SST-34 were used in studies of the pancreas and anterior intestine. In the brain, SST-14 is the major form of somatostatin. SST-14- and SST-34-immunoreactive nerve fibers are distributed throughout the telencephalon, diencephalon, and mesencephalon. In the latter region SST-14 immunoreactivity is concentrated in nerve tracts in the nucleus interpeduncularis. Nerve cells within the olfactory bulbs are immunoreactive only to anti-SST-34. Cells immunostained with anti-SST-14 were localized within the ependymal and subependymal layers of the pars ventralis hypothalami and the subependymal layers of the pars dorsalis thalami. SST-14-immunoreactive perikarya are also distributed within the tegmentum mesencephali. Nerve fibers and cells immunoreactive to anti-SST-34 are detected in the pars ventralis hypothalami but these cells do not colocalize SST-14. Pancreatic islets, distributed within the epithelium and in the submucosal connective tissue at the esophageal-intestinal junction, are only immunoreactive to anti-insulin. The antisera revealed three distinct cell types in the intestinal epithelium: type 1 colocalizes aPY, NPY, and PYY; type 2 colocalizes SST-14 and SST-34; and type 3 demonstrates immunoreactivity only to anti-SST-34. Immunoreactivity to anti-GLP is absent.

Immunoreactivity to peptides belonging to the pancreatic polypeptide family (NPY, aPY, PP, PYY) and to glucagon-like peptide in the endocrine pancreas and anterior intestine of adult lampreys, Petromyzon marinus: an immunohistochemical study

Immunoreactivity of antisera directed against human neuropeptide Y (NPY), anglerfish polypeptide YG (aPY), bovine pancreatic polypeptide (bPP), salmon pancreatic polypeptide (sPP), porcine peptide tyrosine tyrosine (PYY), and salmon glucagon-like peptide (GLP) was investigated in the endocrine pancreas and anterior intestine of adult lampreys, Petromyzon marinus, by immunohistochemical analysis. There was no immunoreactivity to anti-sPP and anti-bPP in any tissue and anti-GLP immunostaining was only present in the anterior intestine. The immunoreactivity to antisera raised against NPY, aPY, and PYY was colocalized within the same small number of cells in the caudal and cranial pancreas of juveniles and the caudal pancreas of upstream migrant adults. These antibodies did not immunostain B- or D-cells and thus, NPY, aPY, and PYY were likely localized in a third cell type (3a) in the lamprey pancreas. Immunostaining of a few cells with only anti-aPY suggested the possibility of a fourth cell type (3b). Immunoreactivity was similar in the cranial and caudal pancreas of male upstream migrants; however, in the female cranial pancreas, a few cells demonstrated intense immunoreaction to anti-aPY, while weaker immunostaining with this antiserum was observed in B-cells. In the intestine of juvenile and upstream migrant lampreys, positive immunostaining to GLP, NPY, aPY, and PYY antibodies was colocalized within the same cell. We believe that this cell may contain PYY/glucagon family peptides. Other intestinal cells immunostained with either GLP or somatostatin-34 antiserum.

Distribution of two forms of somatostatin in the brain, anterior intestine, and pancreas of adult lampreys (Petromyzon marinus)

The distribution of two major immunoreactive forms of somatostatin, somatostatin-14 and somatostatin-34, within the brain, pancreas and intestine of adult lampreys, Petromyzon marinus, was identified using antisera raised against these peptides. Immunostaining of the brain is similar in juveniles and upstream migrants, and somatostatin-14 is the major somatostatin form demonstrated. A few somatostatin-34-containing cells are localized within the olfactory bulbs, thalamus and hypothalamus, but cells immunoreactive to anti-somatostatin-34 in the hypothalamus and thalamus do not co-localize somatostatin-14. Immunostaining of pinealocytes within the pineal pellucida with anti-somatostatin-14 may infer a novel function for this structure. Somatostatin-14 and somatostatin-34 are co-localized within D-cells of the cranial pancreas and caudal pancreas of juveniles and upstream migrants. Numerous somatostatin-34-immunoreactive cells are distributed within the epithelial mucosa of the anterior intestine but not all of these cells cross-react with anti-somatostatin-14. It appears that somatostatin-34 is the major somatostatin in the pancreo-gastrointestinal system of adult lampreys.

Morphogenesis of somatostatin- and insulin-secreting cells in the lamprey endocrine pancreas

The development of the endocrine pancreatic tissue during the entire life cycle of lampreys was provided through a review of previous literature and through a description of new, preliminary immunohistochemical data on a number of species. There seems to be no firm conclusions on the method of development of the endocrine pancreas during embyrogenesis, but observations of 79-day old larvae suggest that somatostatin-positive cells are confined to the epithelium of the alimentary canal, which is also the site at which insulin-immunoreactive islets form. This type of cellular distribution and morphogenesis at the oesophago-intestinal junction continues throughout the larval period. In northern hemisphere species, a caudal pancreatic mass forms at metamorphosis from the transformed epithelium of the bile duct. Evidence is presented to suggest that the process of bile duct degeneration and transformation is highly synchronized and that interference with the morphogenetic event will alter the normal distribution of pancreatic islets in the adult. The position of the bile duct in larvae of southern hemisphere species results in no caudal pancreas in adults. The adult cranial pancreas of all lamprey species, forms from remnants of the larval islets and through proliferation of new islets from the epithelium of the developing intestinal diverticulum. In holarctic lampreys, the cranial and caudal masses are connected by a discontinuous intermediate cord of islets and all three regions contain equal numbers of somatostatin- and insulin-immunoreactive cells. Following metamorphosis, growth of the caudal pancreas occurs through cellular proliferation from within but the cranial pancreas continues to recruit islets from the diverticular epithelium through the upstream-migrant (prespawning) period.

Screening for aminoglycoside auditory toxicity in the old

1. We have investigated 22 patients receiving gentamicin, mean (s.d.) age 78 (6) years for auditory toxicity, using a standard audiometric technique in a sound-treated room (Study 1). 2. Use of a portable audiometer might allow a larger and more representative proportion of patients treated with aminoglycosides to be screened for ototoxicity. A method for detecting high frequency loss suitable for use in the ward was evaluated in 12 volunteers aged 27 (4) years (Study 2). 3. The error inherent in taking hearing at the start of treatment as a reference point was measured in 16 patients, aged 81 (8) years, prescribed non-ototoxic antibacterials (Study 3). 4. A significant (P = 0.05) reduction in hearing threshold was detected in Study 1, although psychometric tests revealed unchanged or improved ability to co-operate. This occurred only at 4000 Hz, the highest frequency used. The magnitude of this loss, mean 2.5 dB, was similar to that of the improvement in threshold detected (P = 0.0004) early in the course of treatment in Study 3. Thus, underestimation of ototoxicity is likely. 5. If a change of threshold of 10 dB or more is taken arbitrarily to represent a real change in hearing, then there was a significant excess of patients in Study 1 with losses at 4000 Hz only (P = 0.032). The six with such losses at this frequency were older than the rest. However, there was a significant (P less than 0.02) positive correlation between log mean predose serum gentamicin concentration and age. Thus, it remains to be determined whether presbyacusis sensitizes those hair cells which it does not destroy to toxic damage. 6. The cumulative dose of gentamicin (for a course of the duration given) was calculated according to published prescribing aids. There was no systematic reduction in the ratio of the dose recommended by a given aid to the dose prescribed in the six with hearing losses as defined above. 7. In Study 2, thresholds obtained at 6000 Hz in the open ward were, on average, 0.9 dB higher than in the sound treated room, but the effect of venue did not reach statistical significance. In the morning thresholds were marginally, but significantly (P = 0.04), lower than in the afternoon. Precision, as measured by the standard deviation of replicate determination, was independent of test conditions. Using multiple (ten) threshold determinations appeared to improve resolution.(ABSTRACT TRUNCATED AT 400 WORDS)

The paradox of using a 7 day antibacterial course to treat urinary tract infections in the community

1. We have studied determinants of outcome of 7 day courses of treatment in 77 middle aged and elderly patients, in whom the general practitioner's diagnosis of urinary tract infections had been confirmed microbiologically. Bacteria were sensitive to cephalexin or trimethoprim. Where there was no preference, treatments were allocated randomly. Compliance was monitored using a pill box with a concealed electronic device which recorded openings of the box. 2. Prescribing trimethoprim, 200 mg twice daily, was more effective than cephalexin, 250 mg four times daily (cure rates 93 and 67%) (P less than 0.006). Those cured and not cured were not distinguished by age, gender, genitourinary history, or infecting organism. 3. Compliance as measured by box openings was worse for cephalexin than for trimethopim (P = 0.01). However, both totality and pattern of compliance were similar in patients cured and not cured by cephalexin. Thus rigid adherence to a conventional course did not promote cure: fewer doses could have been prescribed. 4. Estimating compliance is essential to clinical trials where medication is self-administered. Poor compliance may establish over exacting regimens. Counting box openings did overestimate compliance, but counting residual tablets overestimated it grossly: given the number of openings less than the ideal, there should have been 171 residual tablets, only 55 were found.

A family outbreak of hemolytic-uremic syndrome associated with verotoxin-producing Escherichia coli serotype O157:H7

All five siblings (three boys and two girls, aged 1.5-9 years) in a family developed hemolytic-uremic syndrome associated with verotoxin-producing Escherichia coli O157:H7 at a lakeside vacation cottage during the fall of 1985. All five were hospitalized and made a full recovery. Both parents remained asymptomatic, and neither had evidence of this infection. In four children who were investigated prospectively, free verotoxin was still detectable in the stools for between 3 and 7 weeks. The prodromal diarrheal illness in the children occurred over a 10-day period. The epidemic curve was consistent with a point-source outbreak, but continuous exposure or person-to-person transmission could not be ruled out. The source of the infection was not identified.

Compliance with anti-tuberculous therapy: a field trial of a pill-box with a concealed electronic recording device

We have conducted a field trial of a pill-box containing a concealed electronic device for monitoring compliance in 23 consecutive adult out patients taking a rifampicin/isoniazid combination once daily. In 22 cases, the times when the box was opened were successfully recorded for the entire period (mean (SD) 26 (5) days) between successive clinic visits. In the other patient the record terminated after one week, a broken box being returned. Both totality of compliance (as assessed by box openings) and consistency of compliance (the proportion of the total number of intervals between openings which were of 22 to 26 h in length) were significantly greater in those studied in the intensive than in the maintenance phase of therapy. Patients may have taken the reduction in medication at the end of the intensive phase as signalling cure. A computer program has been developed to display the recorded data. This allowed the physician responsible to assimilate at a glance the patient's tablet-taking habits. In routine practice knowledge of the presence of the device may improve compliance and a discussion of the graphical display may prove of value in counselling.

Distribution of ferric iron in juveniles of the lamprey Petromyzon marinus L

Sites of iron deposition in tissues and organs of juvenile lampreys (Petromyzon marinus L.) were compared in animals feeding on Salmo gairdneri and nonfeeding individuals using light microscopy and the Prussian blue stain. The liver and adipose tissue are the primary sites of iron storage in all animals and they contain slightly higher concentrations of iron in nonfeeding individuals. Substantial amounts of iron are present in several regions of fibrous connective tissue, in cartilage, and in the meninges. The presence of iron-positive granules and globules in both the mucous cells of the epithelium and the lumen of the posterior intestine suggests that this region of the intestine is a site where excess iron is eliminated. Mucous cells of the dorsal epidermis and the gills probably also release excess iron during mucous secretion. Heavy deposits of iron in subepithelial macrophages and light iron staining of the epithelium of the anterior intestine during times of active feeding imply that the epithelium of this part of the intestine is involved in absorption and that macrophages concentrate the iron. The extensive distribution and heavy concentration of iron in this obligate sanguivore may necessitate the existence of an efficient mechanism for controlling iron intake during feeding.

Effects of cycloheximide and puromycin on cytotoxic activity of Escherichia coli verocytotoxin (Shiga-like toxin)

Verocytotoxin (VT)-producing Escherichia coli is closely associated with hemorrhagic colitis and hemolytic uremic syndrome. The diagnosis of this infection requires the demonstration of VT activity in fecal filtrates or the isolation of VT-producing E. coli from stools. To improve the sensitivity of the Vero cell assay for detecting VT, we investigated the interaction between this toxin and cycloheximide and puromycin, agents which, like VT and the related Shiga toxin, are protein synthesis inhibitors. Cycloheximide-treated cells were found to be about eightfold more sensitive to VT, this effect being most pronounced when the drug was added before the toxin. In contrast, puromycin treatment had an antagonistic effect in that it decreased the sensitivity of the cells to VT. In assays of VT in fecal filtrates, the addition of cycloheximide (at 4 to 8 micrograms/ml) increased the sensitivity without affecting the specificity of the assays. Likewise, the use of cycloheximide led to an increase in the sensitivity of the serum VT-neutralizing antibody test by a factor of over eightfold.

Susceptibility of Gardnerella vaginalis to metronidazole, its bioactive metabolites, and tinidazole

The susceptibilities of 510 clinical isolates of Gardnerella vaginalis to metronidazole, its principal oxidative metabolites, and tinidazole were determined by an agar dilution method. The hydroxy metabolite was the most active, with an MIC90 value (minimum concentration that inhibited 90% of the strains) of 1.12 mg/L (5.51 mumol/L). Tinidazole and metronidazole were somewhat less active, with MIC90s of 4.09 mg/L (23.9 mumol/L) and 4.44 mg/L (18.0 mumol/L), respectively. The acid metabolite was inactive, with an MIC90 value of 226.55 mg/L (1.22 mmol/L). These results suggest that the hydroxy metabolite of metronidazole may contribute significantly to the antimicrobial effect of the parent drug in G. vaginalis-associated infections.

Rifampin alone or with trimethoprim for contacts of children with Haemophilus influenzae type b infections

We carried out a nonrandomized, unblinded study to compare the efficacy of rifampin alone with that of rifampin in combination with trimethoprim in the eradication of the Haemophilus influenzae type b (HIB) carrier state among contacts of patients with invasive HIB infection. The study population comprised 17 index patients admitted to hospital with severe HIB infections and 233 contacts, 43 of whom had nasopharyngeal colonization with HIB of the same biotype as that of the index patient. Rifampin in a daily dose of 20 mg/kg (maximum 600 mg) for 4 days eradicated the carrier state in 86% of cases, as did the combination of rifampin at the same dosage and trimethoprim in a daily dose of 5 mg/kg (maximum 160 mg) for 4 days.

Cleaning up pertussis vaccine

The side effects regularly observed with standard pertussis vaccine are thought to be due to its endotoxin content. Using polymyxin-Sepharose affinity chromatography the endotoxin content of the vaccine can be reduced 1000-fold. Assays are currently in progress to test the protective effect of the purified vaccine.

Sensitive method for detecting low numbers of verotoxin-producing Escherichia coli in mixed cultures by use of colony sweeps and polymyxin extraction of verotoxin

High titers of Verotoxin (VT) were released from cell pellets of VT-producing Escherichia coli (VTEC; corresponding to E. coli strains producing "high" levels of Shiga-like toxin) after incubation in polymyxin B (0.1 mg/ml) for 30 min at 37 degrees C. Maximal titers of polymyxin-releasable VT occurred in cells obtained from 5-h Penassay broth cultures and were up to eightfold higher than the peak culture supernatant VT titers which occurred in 8-h cultures. Polymyxin-releasable cell extracts of 5-h broth cultures inoculated with mixtures of VT-positive (VT+) and VT-negative strains had easily detectable VT titers when the proportion of VT+ cells in the mixture was about 1.0%, but culture supernatants were negative for VT even when this proportion was 20%. The results were the same whether the initial inoculum consisted of broth culture mixtures of VT+ and VT-negative strains or colony sweeps (loopfuls of confluent bacterial growth) taken from solid plate media previously inoculated with the broth mixtures. In a clinical study, 80 stool cultures from patients with hemolytic uremic syndrome and family contacts with diarrhea were tested for free fecal VT, VT in polymyxin extracts of colony sweeps (VT/PECS), and VTEC (examination of 20 separate E. coli colonies from primary media for VT production). Of the 80 samples, 40 were positive for at least one of these three tests; all 40 were positive for free fecal VT, and 20 of these were positive for VT/PECS. VTEC (as few as 1 colony out of 20) were only isolated from 14 of the 20 cultures that were positive for VT/PECS. In six cases, the VT/PECS was positive even when none of 20 colonies tested were VT+, suggesting that the procedure was able to detect a proportion of VTEC that was less than one in 20(5%). We conclude that the VT/PECS method is highly sensitive for detecting low concentrations of VTEC in stools and provides a rapid method for screening out stools that are negative for VTEC. The technique should also be of value in epidemiological studies for detecting low numbers of VTEC in animal feces, foods, and environmental samples.

Cation and anion transport pathways in volume regulatory response of human lymphocytes to hyposmotic media

The regulatory volume decrease of osmotically swollen human peripheral blood lymphocytes can be inhibited by agents acting on volume-activated K+- or Cl--transport pathways. Quinine, cetiedil, and 3,3'-dipropylthiadicarbocyanine were found to block the volume-induced K+ transport by interaction with sites on the outside face of the membrane, perhaps by competition with external K+. Drugs known to influence calmodulin action inhibit both volume-induced K+ and Cl- transport to varying degrees. Those inhibitors, particularly of K+ transport, are correlated with their calmodulin-antagonist activity. Penetrating sulfhydryl (SH) reagents (in contrast to nonpenetrating ones) are potent inhibitors of both volume-induced K+ and Cl- movements, indicating the presence of functionally important SH groups located within the membrane or at the cytoplasmic face. A number of agents, such as dipyridamole and oligomycin C, are specific inhibitors of the volume-activated anion pathway. In all respects studied, the inhibition characteristics of the volume-activated K+ pathway of lymphocytes resemble those of the Ca2+-activated K+ channel of red cells. In contrast, the volume-induced anion permeability differs from the primary anion-transport pathway of red cells.

Antibiotic susceptibility of blood and cerebrospinal fluid isolates of Haemophilus influenzae

One hundred and sixty-nine blood and cerebrospinal fluid isolates of Haemophilus influenzae, collected in the Province of Ontario from children and adults from 1976 to 1983, were tested for susceptibility to six conventional and eight newer antibacterial drugs. Most active were ceftriaxone, ceftizoxime and cefotaxime (MIC90 less than or equal to 0.02 mg/l); latamoxef (moxalactam), acrosoxacin and ceftazidime were close behind with MIC90s in the 0.05-0.09 mg/l range. Twenty-five strains (14.8%) were beta-lactamase-producing and thus resistant to ampicillin. There were no chloramphenicol-resistant strains. The isolates showed intermediate but still clinically useful susceptibility to trimethoprim, rifampicin, cefuroxime, piperacillin and chloramphenicol and were least susceptible to gentamicin and sulphamethoxazole.

Susceptibility of Bordetella pertussis to cephalosporin derivatives and imipenem

The in vitro activities of 16 cephalosporin derivatives and imipenem against 60 strains of Bordetella pertussis were examined. Cefoperazone, imipenem, and ceftriaxone were the most active, with MICs that inhibited 90% of the strains of 0.006, 0.05, and 0.1 microgram/ml, respectively. Cephalexin, cephradine, and cefsulodin were the least active, with MICs of 25 to 125 micrograms/ml. The remainder of the agents demonstrated intermediate activity.

In vitro interactions between rifampin and ampicillin or chloramphenicol against Haemophilus influenzae

Twenty clinical isolates of Haemophilus influenzae type b were used to determine the in vitro interactions of rifampin with ampicillin or chloramphenicol. Potential interactions of the drugs were evaluated by calculating the fractional inhibitory concentration index and fractional bactericidal concentration index for each strain after treatments with the drugs alone and in combination. There was no evidence of synergy or antagonisms between ampicillin and rifampin or between chloramphenicol and rifampin. With ampicillin-susceptible H. influenzae type b strains, an additive effect was observed with seven strains, and an indifferent effect was observed with three strains. Similarly, with chloramphenicol-susceptible H. influenzae type b strains, an additive effect was observed with eight strains, and an indifferent effect was observed with two strains.

Anaerobic infection in the neutropenic host: anti-endotoxin effect of polymyxin

The neutropenic mouse model of endotoxin-associated anaerobic sepsis was used to evaluate the anti-endotoxic effect of polymyxin. Administered as two spaced doses after lethal challenge with Bacteroides fragilis polymyxin produced a statistically significant protective effect.

Antibiotic resistance of degraded strains of Bordetella pertussis

The susceptibilities to erythromycin, rifampin, polymyxin B, ampicillin, tetracycline, gentamicin, fusidic acid, trimethoprim, and spectinomycin of five virulent phase I strains of Bordetella pertussis and their degraded phase IV descendants were compared. Increases in MICs of 2- to 16-fold were observed for erythromycin, rifampin, tetracycline, fusidic acid, trimethoprim, and spectinomycin for four of the five degraded strains.

Integrated management of bacteraemic shock in neutropenia

The neutropenic mouse model of endotoxin-associated, enterobacterial sepsis was used to evaluate the individual and cumulative effects of anti-infective, anti-endotoxic, anti-inflammatory and anti-endorphic strategies. Survival was maximized following the administration of ticarcillin, polymyxin, methylprednisolone and naloxone.

Antimicrobial susceptibility of Bordetella pertussis strains isolated from 1960 to 1981

The susceptibilities to erythromycin, rifampin, polymyxin B, ampicillin, tetracycline, gentamicin, fusidic acid, trimethoprim, and spectinomycin of 100 strains of Bordetella pertussis isolated between 1960 and 1981 were compared. No change in susceptibility to any of these drugs was noted.

Reducing the endotoxic activity of pertussis vaccine

Unadsorbed, regular production pertussis vaccine was treated with polymyxin B sulphate at concentrations of 25, 50 and 100 microgram/ml. The toxic activity of treated and untreated vaccines was compared using both the limulus amoebocyte lysate test and the mouse-weight-gain test. Protective efficacy was also assessed by the mouse protection test. No discernible effect on either toxicity or efficacy of the pertussis vaccine was observed. When the vaccine was treated with 5000 microgram/ml of polymyxin, endotoxic activity assessed by the limulus lysate test appeared to be abolished.

Ticarcillin bioassay

An accurate, plate diffusion bioassay for ticarcillin, utilizing the fast-replicating Beneckea natriegens and 4% salt agar, is described in this report. Zones of inhibition were well defined after 3 h, and the limit of sensitivity was around 5.0 mug/ml. The assay is simple to carry out, and duplicate assays can be performed on as little as 40 mul of serum.

Resistance to trimethoprim and other antibiotics in shigellae isolated in the province of Ontario

Antimicrobial susceptibility determinations for three commonly used and seven seldom used antibacterial drugs against 482 strains of shigellae isolated in Ontario during 1977 and 1978 were carried out. Resistance to the first-line treatment drugs, ampicillin and tetracycline, occurred in 20.5 and 39.2% of strains, respectively. The emergence of trimethoprim-sulfamethoxazole resistance was noted for the first time in 3.2% of the strains in 1978. All strains retained their susceptibility to gentamicin, nalidixic acid, and polymyxin but were variably susceptible to chloramphenicol, cephalexin, and rifampin.

Lethal effect of polymyxin B sulfate in experimental Proteus rettgeri infection in mice

The mouse model of intraperitoneal sepsis with Proteus rettgeri was used to evaluate the anti-endotoxic effect of polymyxin B sulfate. An unexpected reversal of the usual protective effect of polymyxin in experimental enterobacterial sepsis was observed in which the lethality of the infection was enhanced.

Characterization of lithium effects on two aspects of T-cell function

Cell surface receptors receive, transduce and relay a variety of environmental signals. These phenomena, which have been extensively characterized in non-lymphoid cells, also appear to play a crucial role in dictating the degree of lymphocyte responsiveness. The nature of these regulatory events is only beginning to be unraveled but the adenylate cyclase-cyclic AMP axis appears to be one of the important controlling systems. Lithium appears to be as important a modulator of lymphocyte responsiveness as previously shown for a variety of other cells and the mechanism of action, in general, is consistent with its role as a putative blocker of adenylate cyclase activation. Indeed, lithium may exert its role as a regulator of lymphocyte responsiveness by acting on specific lymphocyte subpopulations. Direct proof for this is still wanting and consideration of its capacity for action as an imperfect substitute for normal extra- or intracellular cations or on the physiochemical state of the plasma membrane is necessary. Nevertheless, these studies indicate the validity of using lithium for assessing the role of the lymphocyte adenylate cyclase-cyclic AMP system in the generation and expression of regulatory signals leading to modulation of the immune system.

Protective effect of polymyxin B sulfate in experimental enterobacterial infection in mice

The mouse model of intraperitoneal enterobacterial sepsis was used to evaluate the anti-endotoxic effect of polymyxin B sulfate. Single or multiple therapeutic doses of polymyxin, administered either before or after lethal challenge with Serratia marcescens, produced statistically and clinically significant protective effects.

Chloramphenicol bioassay

An accurate plate diffusion bioassay for chloramphenicol is described, in which the fast-replicating Beneckea natriegens and 1.5% salt agar are used. Zones of inhibition were well defined after 3 h, and the limit of sensitivity of the method was around 2 mug/ml. The concurrent presence of gentamicin did not influence the assay. The assay is simple to carry out and duplicate assays can be performed with as little as 100 mug of capillary blood.

Susceptibility of Haemophilus influenzae type b to rifampin and sulfisoxazole

A total of 100 and 97% of Haemophilus influenzae type b strains from major infections were susceptible, respectively, to levels of rifampin and sulfisoxazole attainable in saliva. It is theoretically feasible to eliminate Haemophilus influenzae from the nasopharynx with these drugs.

Susceptibility of Canadida albicans to miconazole

A total of 439 clinical isolates of Candida albicans were tested for susceptibility to miconazole by the agar dilution technique. When tests were read at 48 and 24 h, 56 and 84%, respectively, of the strains were completely inhibited by 4.0 mug of miconazole per ml, the estimated upper limit of probable clinical susceptibility.

Protective effect of polymyxin B sulfate in experimental meningococcal infection in mice

The mouse model of intraperitoneal meningococcal sepsis was used to evaluate the antiendotoxic activity of polymyxin B sulfate independent of its antibiotic effects. Administered either before or after the infective challenge therapeutic doses of polymyxin B sulfate produced small but significant increases in survival over unprotected animals. These results also suggest that endotoxin contributes to the outcome in this variety of Gram-negative infection.

Comparative susceptibility of Candida albicans to amphotericin B and amphotericin B methyl ester

The in vitro antifungal activities of amphotericin B (AMB) and amphotericin B methyl ester (AME) were compared against 465 clinical isolates of Candida albicans. AMB and AME possessed comparable activity against half of the strains, but against the remainder of the strains the activity of AME was slightly lower than that of AMB. Rarely did AME show superior antifungal activity to AMB.

Discrepant results of amphotericin B assays on fresh versus frozen serum samples

Amphotericin B assays on frozen serum samples (-20 degrees C) generally underestimate the serum levels obtained on promptly processed samples. The degree of the discrepancy is variable and independent of the length of time stored.

Successful treatment of Candida endophthalmitis with a synergistic combination of amphotericin B and rifampin

Candida endophthalmitis, caused by transient candidemia, developed in a 14-year-old white girl receiving intravenous hyperalimentation. Antifungal synergism was established in vitro for the combination of amphotericin B and rifampin against the C. albicans isolate. A combined ten-day course of intravenous amphotericin B and oral rifampin was followed by the elimination of the infection and the preservation of good visual acuity.

Microassay foramphotericin B

Depending on the hematocrit, duplicate or triplicate determinations of serum amphotericin B concentration may be made on as little as 100 mul of capillary blood obtained by finger prick. In an accurate plate diffusion bioassay, using Paecilomyces varioti as the indicator organism, levels of the drug in the therapeutic range can be determined fast enough for clinicians to modify their next dose.

Bacterial proteinaceous products (bacteriocins) as cytotoxic agents of neoplasia

Several bacteriocins, bacterial proteinaceous antibiotics, are shown to markedly inhibit the division of various established (neoplastic) mammalian cell lines. The bacteriocins tested originated from Escherichia coli, Pseudomonas aeruginosa, Vibrio cholerae, and Vibrio eltor. Using exponentially growing L60T mouse fibroblasts, the inhibitory effect was concentration dependent, and a growth inhibitory unit, equivalent to cytotoxic index 50, was established. Expression of toxicity as a function of duration of exposure to pyocin required 3 to 4 hr. DNA synthesis was inhibited and reflected the effects on growth inhibition. Maximal sensitivity to the bacteriocin was observed prior to mitosis in the G2 phase of the cell cycle.

Influences of environmental ionic strength, pH, and magnesium ion on bactericidal and lytic activities of -lysin on Bacillus subtilis

The technique of lyophilization has been used to prepare β-lysin that can be stored in aliquots at ordinary refrigeration temperatures. It has permitted the determinations of environmental ionic strength, pH, and magnesium ion concentration favoring bactericidal and lytic activities of this agent. Killing of cells as well as lysis of protoplasts of Bacillus subtilis were favored in environments not more than 0.2 nor less than 0.15 in ionic strength. Of the environmental pH tested (6.0, 7.0, and 7.5), lysis of cells and of protoplasts was most efficient at pH 7.5, whereas bactericidal action was relatively unaffected in this range. The effectiveness of bactericidal action and of lysis of protoplasts decreased as the amount of Mg2+ in the environment increased.