Effect of inhaled preservatives on asthmatic subjects. I. Sodium metabisulfite

Sodium metabisulfite (MBS) is used as a preservative in food and wine and frequently triggers attacks of asthma. To determine the characteristics of responses to inhaled MBS, 30 asthmatic subjects and 16 nonasthmatic subjects inhaled MBS, in concentrations of 6.2, 12.5, 50, and 100 mg/ml, from a DeVilbiss No. 40 nebulizer (DeVilbiss Co., Somerset, PA) in doses ranging from 0.1 to 12.8 mumol. Response was measured as the dose that caused a 20% fall in FEV1 (PD20FEV1). All the asthmatic subjects responded; one of the atopic, nonasthmatic subjects responded and none of the nonatopic, nonasthmatic subjects responded. The response occurred within 1 min, and most subjects recovered to within 10% of baseline after 30 to 40 min. Dose-response curves to MBS were steep and were reproducible, within a 7-day period, to within one doubling dose, with mean PD20FEV1 values of 2.17 and 2.11 mumol in 11 subjects. There was no correlation between PD20FEV1 values to MBS and histamine, and inhalation of MBS did not enhance responses to subsequent challenge with histamine (mean PD20FEV1 to histamine was 0.65 mumol and to histamine 1 h after MBS was 0.74 mumol). Challenge with MBS (mean PD20FEV1 4.07 mumol) did not cause refractoriness to a second challenge 1 h later (mean PD20FEV1 5.39 mumol). Of 20 subjects tested, prior inhalation of 8 mg nedocromil sodium blocked the response to MBS in 15 subjects and reduced it in two others. Cromolyn sodium (4 mg) blocked the response to MBS in three subjects but did not alter the mean PD20FEV1 in the remaining 17 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Epinephrine and phenylephrine increase cardiorespiratory toxicity of intravenously administered bupivacaine in rats

We studied the effects of epinephrine and phenylephrine on the cardiorespiratory toxicity of intravenously injected bupivacaine in Sprague-Dawley rats. Our data show that both epinephrine and phenylephrine significantly increased cardiorespiratory toxicity of intravenously injected bupivacaine (P less than 0.007, X2 analyses with Yates' correction). Our data suggest that epinephrine or phenylephrine added to bupivacaine may be more toxic to cardiorespiratory systems than plain bupivacaine or epinephrine alone or phenylephrine alone when injected intravenously in rats.

Annular-slot arrays as far-infrared bandpass filters

Arrays of both annular and square annular slots in a conducting sheet on a dielectric substrate have been fabricated photolithographically. The structures are shown to behave as bandpass filters in the far infrared, with a resonant wavelength slightly larger than the average circumference or perimeter of the slot. The measured far-infrared transmittance of the annular array is approximately 76% of that predicted by theory, while its resonant frequency agrees with theory to within 5%.

Effect of die spacer on the seating of complete cast gold crowns with grooves

Fifty crowns were constructed with an indirect technique for a standardized Ivorine tooth preparation to determine whether casting relief would improve the seating of complete cast crowns with zinc phosphate cement. The variables were two grooves in the preparations and die spacer casting relief of approximately 20 to 40 micron. The tooth preparations of two groups had no grooves, but castings were made with internal relief for only one group. Three groups had buccal and lingual grooves in the preparation. One group had no relief, a second group had complete relief, and a third group had relief but not in the grooves. The discrepancies noted before and after cementation of the castings were measured. The average discrepancy for each group and the significance between groups was determined. Results of this study demonstrated the following. Die relief significantly improved the seating of complete cast-gold crowns with or without grooves. Omitting die spacer from grooves did not reduce the benefits of relieving the remainder of the die. Partial internal relief was better than no relief. The grooves did not disrupt seating when die spacer application was complete or specifically omitted from the grooves alone.

Ability of specific monoclonal antibodies and conventional antisera conjugated to hematoporphyrin to label and kill selected cell lines subsequent to light activation

A variety of cell lines have been prepared by fusion of the murine WEH1 3B cell line with peripheral blood leukocytes from a patient with chronic granulocytic leukemia. Fusion products were selected for their ability to produce a leukemia-associated antigen (CAMAL) previously described. One such line which originally produced CAMAL subsequently lost this ability and was used as a negative control. A number of antibodies were conjugated to hematoporphyrin (HP) and tested for their ability to bind to cell lines as detected by either fluorescence or by their ability to kill cells after light activation. The antibodies used were: rabbit anti-Hu (a conventional rabbit antiserum raised to membrane preparations from normal human peripheral blood leukocytes which served as a positive control); CAMAL-1 (a monoclonal gamma 1 antibody with specificity for the CAMAL antigen); and L1210 (an irrelevant monoclonal gamma 1 antibody). HP was conjugated to the antibodies by a carbodiimide procedure. When labeled cells were examined by fluorescence microscopy, it was apparent that both the rabbit antibody and CAMAL-1:HP showed positive labeling. The ability of the antibody:HP conjugates to kill labeled cells following light activation was tested. It was shown that rabbit anti-Hu:HP and CAMAL-1:HP conjugates were capable of killing significant numbers of cells when HP concentrations were as low as 1.2 ng/10(6) cells, whereas similarly treated cells exposed to either L1210:HP or HP alone did not exhibit significant killing until concentrations reached 240 and 120 ng/10(6) cells, respectively. Further experiments in which other cell lines were tested, all at HP concentrations of 12 ng/10(6) cells, demonstrated that those lines producing CAMAL were killed, whereas negative lines were not.

Haemorrhage from smooth muscle tumours of the upper gastro-intestinal tract

Eight patients with haemorrhage from smooth muscle tumours of the upper gastro-intestinal tract were treated during a 10 year period from 1973 to 1982. Seven of the tumours were benign and one a malignant leiomyoblastoma. Seven tumours were sited in the stomach and there was one duodenal lesion. Endoscopy was performed in all eight cases and made the diagnosis definitively in four. In two cases the diagnosis was confirmed on barium meal and in the other two, diagnosis was eventually made at laparotomy. Two patients were shocked on admission and required emergency surgery. In one case a diameter greater than 10 cm suggested malignant potential and wide local resection was performed. In one other case with a tumour in the antrum, a distal partial gastrectomy was performed, and in the case with leiomyoblastoma a proximal gastrectomy was performed. One case was lost to follow-up. The mean follow-up in six cases free of disease with benign tumour was 2.6 years. The patient with a tumour of greater than 10 cm in diameter remains well at 18 months follow-up and the patient with a malignant leiomyoblastoma died 2 years after surgery.

Technique for applying porcelain to pontics of fixed partial dentures

A technique has been presented to be used to make pontics for metal-ceramic fixed partial dentures. Use of the porcelain/wax system is advantageous, especially when multiple pontics are involved.

Use of paint-on die spacers in preparations with grooves

Film thickness of paint-on die spacer materials was measured on axial walls and in grooves. Two different materials and two different modes of application were tested. From the data presented, the following conclusions can be drawn: There are potentially significant differences in film thickness produced with different die spacing materials. The technique used to apply die spacer can affect the film thickness produced. Careful application of Pactra airplane dope will not result in significant accumulation of die spacer in the groove. Tru-fit die spacer produced generally erratic film thickness and demonstrated a potentially significant amount of pooling in the groove base. Further study is warranted to determine if use of die spacer in grooves will improve the seating of castings.

The hormonal and cellular control of Sertoli cell secretion

Sertoli cells synthesize and secrete a number of cell-specific products including androgen binding protein (ABP), as well as "serum proteins" such as transferrin. The secretion of these proteins is regulated by extra-testicular hormones such as FSH and insulin; Leydig cell-produced steroids and proopiomelano-cortin-derived peptides; and the presence of peritubular myoid cells and/or factors secreted by these cells. Many of the Sertoli cell proteins are secreted in a cyclic fashion during the different stages of the spermatogenic cycle suggesting communication between Sertoli cells and developing germ cells. The availability of quantitative measurements for Sertoli cell-specific proteins such as ABP make it feasible to follow Sertoli cell function in vivo by measuring these products in serum. A bidirectional secretion of proteins by Sertoli cells is proposed to explain the presence of specific peptides in the male reproductive tract and blood.

Asbestos exposure and lymphomas of the gastrointestinal tract and oral cavity

An epidemiological case-control study of non-Hodgkin's lymphomas revealed an excess of male patients with large-cell lymphomas primary to the gastrointestinal tract and oral cavity who had evidence of substantial exposure to asbestos. Between 1977 and 1981, 28 men with large-cell lymphomas primary to these sites were interviewed about previous environmental exposure. Pathology slides from 26 of these cases were reviewed by haematopathologists, who confirmed each to be non-Hodgkin's lymphoma of large-cell type. Neighbourhood controls were matched to patients for age, race, and sex. 13 matched pairs were discordant for asbestos exposure, and in 12 of these the exposed individual was a lymphoma patient. 10 patients and 1 control also reported a history of malaria.

Characterization of two newly established human cell lines from patients with large-cell anaplastic lung carcinoma

Two permanent cell lines, designated LU-65 and SK-Luci-6, were established from large-cell anaplastic lung cancers of two patients. Both cell lines grew as solid tumors in nude mice. The histologic pattern of the tumors in the nude mouse resembled that of the primary lung cancers in that the xeno-transplanted tissues showed no distinctive features indicative of cell type, a finding consistent with origin from a large-cell anaplastic lung cancer. Cells from both lines formed clones in semisolid agar. Flow cytometric analysis of SK-Luci-6 showed a hypertriploid stemline with a very high RNA-index. Line LU-65 had a hyperdiploid stemline evolving into a hypertriploid stemline with a high RNA-index. Chromosome analysis showed aneuploidy with abnormalities and marker chromosomes in both tumor cell lines. The isoenzyme pattern of LU-65 and Sk-Luci-6 indicated that they were of human origin and distinct from HeLa cells or another common contaminating line. Both cell lines released biologically active agents that could have caused the neutrophilia and hypercalcemia seen in the patients.

In vitro cellular effects of hematoporphyrin derivative

Several in vitro cell systems were exposed to hematoporphyrin derivative (HPD): established lines of rat kangaroo epithelial kidney; normal mouse embryonic fibroblasts; and differentiated neonatal rat myocardial cells. The uptake of HPD (25 to 100 micrograms/ml) by individual cells occurred rapidly over a 2-hr period and leveled off by 24 hr. HPD was excreted from cells by 48 hr after exposure. However, a low level of HPD (above background) was maintained in cells for up to 4 days following cessation of exposure. Intracellular binding of HPD was to mitochondria as demonstrated by fluorescence microscopy. HPD was also shown to have a growth-inhibiting effect on rat kangaroo cells without added light. The growth effects on mouse cells were less marked.

Specificity of translation of spore polypeptides in bacillus in vitro systems

Cell free extracts prepared from exponentially growing Escherichia coli and Bacillus cereus as well as from Bacillus cereus at the end of exponential growth were optimized for various factors required for amino acid incorporation when programmed with Bacillus ribonucleic acid. All three preparations synthesized glutamine synthetase antigen when ribonucleic acid from a Bacillus subtilis strain that overproduces glutamine synthetase was added. The post exponential Bacillus cereus extract, however, was most active for the synthesis of Bacillus cereus sport coat antigen when supplemented with the appropriate ribonucleic acid. There appears to be some specificity in the translation of at least this sporulation messenger RNA.

The power spectra of visually evoked potentials to pseudorandom contrast reversals of gratings

Visually evoked potentials (VEPs) were recorded in response to the temporal pseudorandom contrast reversal of spatially sinusoidal gratings with different spatial frequencies. The stimulus mimicked bandwidth limited white noise in the temporal domain except for an inherent periodicity which permitted signal averaging. The power spectra of the resulting VEPs were calculated. For high spatial frequency gratings (7.5-15 c/degree) VEP power was localized to the temporal frequency range from 3 to 7 Hz. For medium spatial frequency gratings (0.75-3 c/degree) VEP power was distributed in a roughly bimodal way with peaks near 6 and 18 Hz. The VEP power spectra due to high frequency gratings were similar in 2 subjects studied in detail, but the power spectra to medium frequency gratings differed substantially.