Use of the Malthus conductance growth analyser to determine numbers of thermophilic streptococci on stainless steel

The use of the Malthus conductance growth analyser for the detection of Streptococcus bovis attached to stainless steel surface was evaluated. A comparison between the results from acridine orange epifluorescence direct counts, swab recovery viable count and conductance estimates of attached cell concentrations, based on calibrations for planktonic cells, showed that the conductance results were up to 2 log10 greater than the epifluorescence results and the swab counts. The growth rates of planktonic and attached cells were similar over 16 h using the Malthus technique. This suggests that the Malthus technique detects more attached cells of Strep. bovis than epifluorescence microscopy or swab recovery.

Methylation of the 5' CpG island of the endothelin B receptor gene is common in human prostate cancer

Production of the potent vasoconstrictor endothelin-1 (ET-1) by human prostate cancer cells accompanies prostate cancer progression in vivo. The predominant endothelin receptor expressed by normal prostate epithelium, ETB, is not expressed by any of the established human prostate cancer cell lines, and ETB binding is decreased on prostate cancer tissues. ETB, which may mediate ET-1 clearance and may inhibit ET-1 secretion, is encoded by a gene that contains a 5' CpG island encompassing the transcriptional regulatory region. We examined this regulatory region of the ETB receptor gene (EDNRB) to determine whether hypermethylation of cytidine nucleotides accompanies decreased ETB expression in human prostate cancer. We found somatic methylation of CpG island sequences in EDNRB in 5 of 5 human prostate cancer cell lines, 15 of 21 primary prostate cancer tissues, and 8 of 14 prostate cancer metastases (70% of samples overall). Normal tissues contained only unmethylated EDNRB. Treatment of human prostatic carcinoma cell line cultures with 5-azacytidine induced ETB mRNA expression, suggesting that CpG island methylation changes might accompany the apparent transcriptional silencing of EDNRB in vivo.

The use of mechanistically defined chemical mixtures (MDCM) to assess component effects on the percutaneous absorption and cutaneous disposition of topically exposed chemicals. I. Studies with parathion mixtures in isolated perfused porcine skin

Recently, attention has been directed to the risk assessment of cutaneous exposure to chemical mixtures rather than to only a single compound since this is the exposure scenario in the environment, residence, and work place. Using acetone or dimethylsulfoxide (DMSO) (80% in water) as a vehicle, percutaneous absorption and cutaneous disposition of parathion (PA) were studied following PA (40 microg/cm2) dosing on isolated perfused porcine skin as mechanistically defined chemical mixtures (MDCM) consisting of the surfactant sodium lauryl sulfate (SLS), the rubefacient methyl nicotinate (MNA), and the reducing agent stannous chloride (SnCl2). A full 2 x 4 factorial design was used to asses treatment effects and potential interactions. More radiolabel was absorbed with DMSO than with acetone albeit an earlier peak flux time but lower peak flux was observed with acetone than with DMSO. The absorption flux rate profiles with DMSO continued increasing but bipeak-featured profiles were observed with acetone. SLS enhanced PA absorption with both DMSO and acetone. The presence of MNA in both vehicles blunted the absorption rate curves without significantly changing total absorption. SnCl2 blocked PA absorption and increased residue level on the skin surface and in the stratum corneum (SC). The venous flux profiles were mixture-dependent and highly reproducible within treatment groups. Higher level interactions were also noted. This study indicated multiple levels of interactive effects on PA absorption which must be incorporated into any effort to identify critical mechanisms which affect risk assessment of topically exposed mixtures. It was suggested that the chemicals selected in a topically applied mixture may have significant effects on the penetration/distribution pattern and percutaneous absorption profile of a toxicant/drug in the mixture. The MDCM approach may be useful in a screening or triage approach to identify mixture components which affect marker chemical absorption as well as identify potential mechanisms which deserve further attention. Risk assessment efforts could then be focused on those mixtures, containing these critical components, which would be expected to have the greatest penetration and absorption.

An uncertain role for p53 gene alterations in human prostate cancers

Inactivation of the p53 gene has been implicated in prostate cancer progression. To determine the role of p53 inactivation in the progression of clinical prostatic carcinomas, we assessed 67 tumors derived from patients with clinically localized disease for chromosome 17p and p53 gene allelic loss, p53 gene mutations using single-strand conformational polymorphism and direct sequencing, and p53 protein expression using immunohistochemical staining. Of 55 informative tumors, 10 demonstrated loss of 17p or the p53 gene; however, only a single tumor had a mutation in its remaining p53 allele. Significant p53 overexpression was observed in 2 of 38 tumors, and 9 others had faint staining of a few nuclei ( < 1%). p53 overexpression occurred in no informative tumor with allelic loss or mutation. In a 1-7-year follow-up, positive immunohistochemical staining did not confer an increased risk of recurrence (risk of recurrence, 0.86, P = 0.78), whereas allelic loss of chromosome 17p appeared to be highly correlated with recurrence (risk of recurrence, 3.7, P = 0.003). In an unrelated group of 42 patients with metastatic prostate cancer, p53 overexpression was found in 26 tumors (62%), and 15(36%) had high grade staining. Neither the presence nor the degree of expression correlated with time to progression or time to death. This series suggests that p53 gene inactivation is rare in primary prostatic tumors, not essential to the development of prostate cancer metastases, and of limited use as a prognostic marker in patients with primary or metastatic disease. Another gene or genes on chromosome 17p may be involved in prostate cancer progression.

Quantitative percutaneous absorption and cutaneous distribution of binary mixtures of phenol and para-nitrophenol in isolated perfused porcine skin

Chemical exposure to skin remains an important route by which systemic toxicity may occur. However, chemicals are seldom contacted singly in neat form and generally are present as a mixture. A total of 56 8-hr isolated perfused porcine skin flap (IPPSF) topical experiments were used to study the percutaneous absorption and cutaneous distribution of binary mixtures (solute/solvent) of 14C-labeled phenol vs p-nitrophenol (PNP) at two concentrations (4 micrograms/cm2 vs 40 micrograms/cm2) in two vehicles (acetone vs ethanol) under occluded vs nonoccluded dosing conditions. Pertinent comparisons were made to determine if dose, vehicle, or occlusion had a significant effect on absorption, localization of the test compounds, or total recoveries. Total recoveries were much greater in all cases for PNP than phenol. Absorption, penetration into tissues, and total recoveries of phenol were greater under occluded conditions than nonoccluded. Absorption and penetration of phenol into tissues were greater with ethanol than with acetone under nonoccluded conditions, but the opposite was observed under occluded conditions. Percentage of applied dose penetration into tissues was greater from low-dose phenol in acetone than high-dose, suggesting a fixed absorption rate. This was also seen for PNP, but only under occluded conditions. Neither phenol dose,vehicle, or occlusion had any significant effect on the labeled phenol seen in the stratum corneum or on time of peak flux, a finding which limits the usefulness of noninvasive stratum corneum sampling to assess topical penetration. There was greater absorption and penetration into tissues of PNP from acetone than from ethanol. PNP dose had a significant effect on time of peak dose, with low-dose PNP taking longer to reach its peak. Neither PNP dose, vehicle, nor occlusion had any significant effect on total recovery of labeled PNP. The results suggest that comparative absorption of phenol and PNP are vehicle-, occlusion-, and penetrant-dependent. These factors must be considered when comparing absorption data between studies. These findings suggest that single chemical data (the compound applied neat) is not predictive of even binary mixtures and that exposure conditions further modulate disposition.

Comparison of open and endourologic approaches to the obstructed ureteropelvic junction

OBJECTIVES

To compare open pyeloplasty with three minimally invasive modalities: antegrade endopyelotomy, Acucise endopyelotomy (Applied Medical, Laguna Hills, Calif), and laparoscopic pyeloplasty.

METHODS

Forty-five adult patients with ureteropelvic junction obstruction were managed by one of the above four techniques. Success rates, analgesic use, length of hospital stay, recovery time, and complications were compared between each of the four groups.

RESULTS

Successful relief of obstruction was achieved in 100% of patients undergoing open and laparoscopic dismembered pyeloplasty, 78% undergoing Acucise endopyelotomy, and 77% undergoing antegrade percutaneous endopyelotomy. Acucise endopyelotomy results in shorter convalescence (1 week) than antegrade endopyelotomy (4.7 weeks), laparoscopic pyeloplasty (2.3 weeks) or open pyeloplasty (10.3 weeks). Complication rates appear to be similar among all groups.

CONCLUSIONS

Our limited data imply that Acucise endopyelotomy offers low morbidity with success rates comparable to antegrade pyeloplasty, whereas laparoscopic pyeloplasty is as effective as open pyeloplasty with diminished morbidity.

Toxicokinetics of topical sulfur mustard penetration, disposition, and vascular toxicity in isolated perfused porcine skin

Sulfur mustard bis(2-chloroethyl) sulfide (HD) is a bifunctional alkylating agent that causes cutaneous vesication. The isolated perfused porcine skin flap is an in vitro model that has been used to study this toxic response. The purpose of this study was to formulate a toxicokinetic model of HD penetration and cutaneous disposition as an aid in correlating critical steps in the pathogenesis of vesication to HD concentrations in different regions of skin. [14C]HD was dosed topically in ethanol at 10.0 mg/ml in a 7.5-cm2 dosing site and venous efflux samples were collected over 2, 4, or 8 hr. At the termination of the experiment, stratum corneum tape strips, core biopsies for serial sections, and the entire skin flap were collected for radioassay. Peak 14C-radiolabel flux occurred within 5 to 60 min in all skin flaps, much earlier than signs of HD-induced toxicity. A toxicokinetic model was used to quantitate the time profile of HD disposition in different skin compartments. Estimates of vascular and extracellular volume changes due to topical HD toxicity were estimated using radiolabeled albumin and inulin infusions. A second toxicokinetic model, with a time-variant distribution rate, was used to simulate volume changes. In order to accurately predict HD disposition, it was necessary to add another compartment as a reservoir for slowly released metabolites of HD. This model provides a quantitative profile of the time course of HD (or metabolites) disposition within skin which would aid in the interpretation of mechanistic studies of vesication as well as in designing interventive antivesicant drug strategies.

Frequent loss of chromosome arms 8p and 13q in collecting duct carcinoma (CDC) of the kidney

Collecting duct carcinoma (CDC) is a malignant renal neoplasm that is believed to arise from the epithelium of the ducts of Bellini in the distal nephron. These tumors are clinically aggressive and more often occur in a younger population than is typical of the more common clear cell renal carcinoma (RCC). Using highly informative polymorphic microsatellite markers on chromosome arms 3p, 5q, 6q, 9p, 9q, 11p, 13q, 17p, and 18q, we analyzed DNA from nonmalignant and tumor tissue in 6 cases of CDC. We found no evidence of 3p loss of heterozygosity (LOH) in these renal tumors by using multiple markers, a finding that distinguishes CDC from RCC in which 3p LOH has frequently been observed. We found LOH of 8p in 50% of the tumors examined; in addition, we observed LOH of 13q in 50% of the tumors studied. Interestingly, 8p LOH may be associated with high stage and poor clinical prognosis. These data suggest that the molecular events responsible for the development of CDC differ from those associated with the origin of RCC, and that tumor suppressor genes on 8p and 13q may be involved in the pathogenesis of CDC.

Allelic loss of the retinoblastoma gene in primary human prostatic adenocarcinomas

Inactivation of the retinoblastoma (Rb) gene has been implicated in the genesis and progression of a number of tumor types, including prostatic adenocarcinomas. We have analyzed a series of 46 surgically-resected human prostatic adenocarcinomas for allelic loss of the Rb gene with PCR amplification of a highly polymorphic region of the gene. 41 of 46 tumors (89%) were informative and 11 of these (27%) had lost one Rb allele. The relative frequency of this occurrence suggests that inactivation of the retinoblastoma gene may be an important event in prostate carcinogenesis.

Cytidine methylation of regulatory sequences near the pi-class glutathione S-transferase gene accompanies human prostatic carcinogenesis

Hypermethylation of regulatory sequences at the locus of the pi-class glutathione S-transferase gene GSTP1 was detected in 20 of 20 human prostatic carcinoma tissue specimens studied but not in normal tissues or prostatic tissues exhibiting benign hyperplasia. In addition, a striking decrease in GSTP1 expression was found to accompany human prostatic carcinogenesis. Immunohistochemical staining with anti-GSTP1 antibodies failed to detect the enzyme in 88 of 91 prostatic carcinomas analyzed. In vitro, GSTP1 expression was limited to human prostatic cancer cell lines containing GSTP1 alleles with hypomethylated promoter sequences; a human prostatic cancer cell line containing only hypermethylated GSTP1 promoter sequences did not express GSTP1 mRNA or polypeptides. Methylation of cytidine nucleotides in GSTP1 regulatory sequences constitutes the most common genomic alteration yet described for human prostate cancer.

Molecular biology of prostate cancer

A number of genetic changes have been documented in prostate cancer, ranging from allelic loss to point mutations and changes in DNA methylation patterns (summarized in Fig 1). To date, the most consistent changes are those of allelic loss events, with the majority of tumors examined showing loss of alleles from at least one chromosomal arm. The short arm of chromosome 8, followed by the long arm of chromosome 16 appear to be the most frequent regions of loss, suggesting the presence of novel tumor suppressor genes. Deletions of one copy of the Rb and p53 genes are less frequent as are mutations of the p53 gene, and accumulating evidence suggests the presence of an additional tumor suppressor gene on chromosome 17p, which is frequently inactivated in prostate cancer. Alterations in the E-cadherin/alpha catenin mediated cell-cell adhesion mechanism appear to be present in almost half of all prostate cancers, and may be critical to the acquisition of metastatic potential of aggressive prostate cancers. Finally, altered DNA methylation patterns have been found in the majority of prostate cancers examined, suggesting widespread alterations in methylation-modulated gene expression. The presence of multiple changes in these tumors is consistent with the multistep nature of the transformation process. Finally, efforts to identify prostate cancer susceptibility loci are underway and will hopefully elucidate critical early events in prostatic carcinogenesis.

Laparoscopic management of testicular pain after embolotherapy of varicocele

We report a patient who underwent embolization of a varicocele for chronic testicular pain with Gianturco coils and developed increased bilateral pain. Complete pain relief was achieved by laparoscopic resection of both spermatic cords. The case provides insights into the pathophysiology of testicular pain and may suggest alternative therapies for chronic orchialgia.

Determination of physicochemical properties of phenol, p-nitrophenol, acetone and ethanol relevant to quantitating their percutaneous absorption in porcine skin

A knowledge of the rate and extent of chemical absorption across the skin is central to both transdermal drug delivery and cutaneous toxicology. Toward gaining sufficient insight into the relevant mechanisms involved in percutaneous absorption of topically applied agents in solution to validate a predictive model, we have 1) estimated porcine stratum corneum/water partition coefficients of two 14C-labeled compounds of interest (phenol and p-nitrophenol), and 2) measured dynamic surface evaporation from dosed excised porcine skin of these two radiolabeled compounds and two 14C-labeled commonly employed vehicles (acetone and ethanol). The surface evaporation profiles were fit to a kinetic model designed to estimate the liquid/vapor parameters for application to a general biophysically-based model of percutaneous absorption. In an effort to obtain more robust estimates of model parameters, corresponding evaporation experiments were effected on the isolated perfused porcine skin flap (IPPSF) under the same experimental conditions. Stratum corneum/water partition coefficients were determined for phenol and p-nitrophenol using a stratum corneum preparation from excised porcine integument.

Genetic alterations in prostate cancer

A number of genetic changes have been documented in prostate cancer, ranging from allelic loss to point mutations and changes in DNA methylation patterns (summarized in Fig. 1). To date, the most consistent changes are those of allelic loss events, with the majority of tumors examined showing loss of alleles from at least one chromosomal arm. The short arm of chromosome 8, followed by the long arm of chromosome 16, appear to be the most frequent regions of loss, suggesting the presence of novel tumor suppressor genes. Deletions of one copy of the Rb and p53 genes are less frequent, as are mutations of the p53 gene, and accumulating evidence suggests the presence of an additional tumor suppressor gene on chromosome 17p, which is frequently inactivated in prostate cancer. Alterations in the E-cadherin/alpha-catenin-mediated cell-cell adhesion mechanism appear to be present in almost half of all prostate cancers and may be critical to the acquisition of metastatic potential of aggressive prostate cancers. Finally, altered DNA methylation patterns have been found in the majority of prostate cancers examined, suggesting widespread alterations in methylation-modulated gene expression. The presence of multiple changes in these tumors is consistent with the multistep nature of the transformation process. Finally, efforts to identify prostate cancer susceptibility loci are under way and may elucidate critical early events in prostatic carcinogenesis.

Tumor suppressor gene allelic loss in human renal cancers

It is now apparent that multiple genetic alterations, including oncogene activation and tumor suppressor gene inactivation, are necessary steps in carcinogenesis. We have studied this concept in renal cancers by looking at specific tumor suppressor genes implicated in several allelotyping studies. Primary, predominantly low stage renal tumors of varying grades and histologic subtypes were investigated for allelic loss of 3p, 17p and the p53 gene, the DCC gene and the Rb gene and its product. 3p loss occurred in 47% of tumors studied and was much more common in clear cell cancers (85%). 17p and p53 gene loss were relatively uncommon events with only 6 of 42 tumors demonstrating loss. None of the tumors with typical histologies had allelic loss of the DCC gene, though loss did occur in leiomyosarcoma and a collecting duct tumor. Allelic loss of the Rb gene occurred in one clear cell tumor, the leiomyosarcoma, and, interestingly, in both collecting duct tumors in this series. Allelic loss of the Rb gene was correlated with little or no RB protein expression as judged by immunohistochemistry. At all loci studied, allelic loss did not appear to correlate with tumor grade or stage. These results suggest that inactivation of the p53, Rb, and DCC genes by allelic loss are uncommon events in the early stages of renal carcinogenesis.

Tubularized neourethra following radical retropubic prostatectomy

A 1.5 cm. tubularized neourethra was formed using an anterior bladder flap as part of bladder neck reconstruction after radical retropubic prostatectomy in 69 consecutive patients with clinically localized prostate cancer (study group). Postoperative continence (defined as requiring no protection for any activity) was assessed by history at 3 months (all men) and 6 months (45 of 69 men). Continence in the study group was compared to that of 45 men with 6 months of followup who underwent radical retropubic prostatectomy without tubularization of the anterior bladder (control group). At 3 months 38 of 69 men (55%) were continent in the study group and 14 of 45 (31%) were continent in the control group (p < 0.03). At 6 months 39 of 45 men (87%) were continent in the study group compared to 21 of 45 (47%) in the control group (p < 0.01). Upright cystograms performed on men with and without the tubularized neourethra after radical retropubic prostatectomy suggest that a neourethra proximal to the external sphincter may increase resistance in this area and result in early return of urinary control in men undergoing radical retropubic prostatectomy.

The Beck Depression Inventory: item order and the impact of response sets

The lack of subtle content in the item groups of the Beck Depression Inventory (BDI) and the consistency in the ordering of the items from least to most pathological make this instrument unduly susceptible to either defensive or malingering response sets. Two experimental forms were developed for the BDI: a backwards version (a simple reversal of the order of items within each group) and a random-order version. These forms, together with the original item order, were given to college undergraduate women along with the Depression scale from the MMPI and the Burks-Martin Questionnaire covering recent life changes and current stressful situations. The random order BDI results in a significantly higher depression score than did either the original or backwards version. Correlations with the other instruments were comparable for all three forms. The random order of items within each set appears to break up a response set to endorse either the first or last item and is, therefore, recommended.

A chromosome 19 clone from a translocation breakpoint shows close linkage and linkage disequilibrium with myotonic dystrophy

The gene for myotonic dystrophy (DM), the most common form of adult muscular dystrophy, is situated on the proximal long arm of chromosome 19. Although there exist markers that are tightly linked to the DM locus, its precise location is unknown. The identification and characterization of additional DNA probes closely linked to the DM locus continue to be priorities. In this study, we report on the linkage between a new DNA marker, designated p alpha 1.4P, and the DM locus in 50 families. The probe p alpha 1.4P was derived from a cloned breakpoint junction fragment from the chromosomal translocation t(14;19)(q32;q13.1). This translocation has been previously described in some cases of chronic lymphocytic leukemia. We have identified a BanI restriction fragment length polymorphism that is detected by p alpha 1.4P. Segregation analysis between this RFLP and DM revealed close linkage between the two loci (lod = 10.95, theta = 0). Furthermore, statistical evidence for linkage disequilibrium between p alpha 1.4P and the DM locus in a French Canadian population was found. Finally, by means of a somatic cell hybrid mapping panel, p alpha 1.4P was sublocalized to 19q12----19q13.2.

Dopamine uptake blockers protect against the dopamine depleting effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the mouse striatum

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a recently described neurotoxin, produces a marked dopamine (DA) depletion in the mouse striatum. In this study, a series of DA uptake blockers was tested for their ability to prevent this effect of MPTP. The agents tested (amfonelic acid, benztropine, bupropion and mazindol) completely protected against DA depletion in the mouse striatum when given before DA-depleting doses of MPTP were administered, whereas atropine and trihexyphenidyl (which were employed for comparative purposes) did not. DA uptake blocking agents appear to represent a second general class of compounds, monoamine oxidase inhibitors being the first, which protect against the biologic effects of MPTP in the mouse.

A comparative clinical study of two pit and fissure sealants: 7-year results in Augusta, GA

This 7-year evaluation of the Augusta study reinforces earlier conclusions regarding the long-term retention of sealants and their efficacy in caries protection. Although more time will be required to answer all the questions about sealants, sufficient data are now available to document their efficacy as caries-preventive agents. It is imperative that the dental profession provide this safe and effective preventive technique for the public so that dental disease can either be reduced or further postponed.

Comparison of bubble and membrane oxygenators in short and long perfusions

Eighty patients had cardiopulmonary bypass (CPB), half having short (109 +/- 11 minutes) perfusions and half having long (188 +/- 14 min) perfusions. Twenty patients in each group were perfused with bubble oxygenators (Bentley, Harvey, or Galen) and 20 with membrane oxygenators (Modulung or Teflo). Hemodilution to a hematocrit value of 22.5% +/- 1.4% and hypothermia to 28 degrees +/- 2 degrees C were used in all patients. Complete hemograms, sequential multiple analyzer 18 tests, coagulation profiles, blood gases and pH, three immunoglobulins, and two complement fraction proteins were sampled as follows: three times before perfusion, one to ten times during perfusion, 1 hour immediately after perfusion, and 4, 24, and 48 hours postoperatively. Data in concentration terms were compared statistically and reported as mean and standard error for each subset. Additionally, rates of gain or loss were calculated in terms of quantity per liter of blood pumped per minute. During perfusion for both duration sets, use of a membrane oxygenator resulted in greater pump flows (4.55 +/- 0.15 L/min versus 3.75 +/- 0.11 L/min), lower total peripheral resistances (1,125 +/- 63 dynes.sec.cm-5 versus 1,652 +/- 115 dynes.sec.cm-5), and greater urinary outputs (9.4 +/- 1.1 ml/min versus 2.2 +/- 0.6 ml/min) than in the bubble oxygenator subsets. Comparisons of measured and calculated data in the immediate postperfusion interval showed no differences between bubble and membrane oxygenator subsets for short perfusions. In long perfusions, the membrane subset had lower plasma hemoglobin and white cell concentrations and generation rates, smaller (3 to 8 1/2 times) losses of IgG, IgM, C3 and shed blood necessitating less transfusion, and greater C4 losses. The membrane oxygenator systems used were more complex and costly and offered no advantages for short perfusion in adults. In anticipated long perfusions or where bleeding may be a problem, a membrane oxygenator appears more efficacious than bubble systems. For perfusions of less than 2 hours, membrane oxygenators had no biochemical or hematologic advantage over the bubble devices used in this study.

A comparative study of two pit and fissure sealants: three-year results in Augusta, Ga

A total of 254 children were examined 36 months after a single application of sealant. In 128 children, 201 permanent first molars were treated with Delton, and, in 126 children, 205 permanent first molars were treated with Nuva-Seal. Delton was completely retained on 80% of all paired permanent first molars, partially retained on 10%, and completely lost on 10% of the study teeth. Nuva-Seal was completely retained on 60% of all paired permanent molars, partially retained on 21%, and completely lost on 19% of the study teeth. Delton was 69% effective in preventing occlusal caries on permanent first molars three years after a single application. Nuva-Seal was 39% effective in preventing occlusal caries on permanent first molars three years after a single application. Both sealants have been shown to prevent dental caries on permanent first molars of children three years after a single application.

A comparative study of two pit and fissure sealants: two-year results in Augusta, Ga

Two pit and fissure sealants, an autopolymerized unfilled resin, and an ultraviolet-light-curing unfilled resin, applied to the permanent first molars of children are compared in terms of retention and efficacy.

Purification of human MM and ZZ alpha 1-antitrypsin

Alpha -1-antitrypsin is the main protease inhibitor in human serum. Certain variants or phenotypes of this protein are associated with diseases of the liver and lung. The availability of purified alpha-1-antitrypsin of various phenotypes would be useful in studies exploring these associations. A two-step purification procedure is presented which involves affinity chromatography on isolubilized conconavalin A followed by preparative starch gel electrophoresis. This simple and rapid method has provided both MM and ZZ alpha-1-antitrypsin in highly pure and active form.

Incorporation of radiolabelled fibrinogen into venous thrombi induced in dogs

The time course and locus of radiolabelled fibrinogen (RLF) incorporation into venous thrombi were studied in dogs. Incorporation of radiolabelled fibrinogen (RLF) into fresh venous thrombi induced in vivo was studied by serial autoradiography, well-counting and surface counting. Autoradiographs disclosed diffuse incorporation of RLF into thrombi formed before and after RLF injection. Well-counting data also reflected thrombus RLF accumulation in both instances, although this accumulation was discernible earlier in thrombi induced in the presence of circulating RLF. Thrombi induced prior to RLF injection were detectable by surface counting after six hours. These studies support the potential value of RLF in detecting human venous thrombosis but also point out the limitations of the technique as well as questions which require clarification.

Reduction of aromatic hydrocarbons by lithium in ethylenediamine

Various aromatic hydrocarbons, which can be assumed to represent some of the aromatic structures present in coals and chars, have been reduced under forcing conditions using lithium in ethylenediamine. It was found that: (i) Aromatic hydrocarbons highly substituted by alkyl or alicyclic groups are resistant to reduction. (ii) The less substituted benzene hydrocarbons and diphenyl-type structures yield, in addition to a proportion of fully reduced material, compounds containing a single olefinic bond which tends to resist further reduction. ��� (iii) Highly condensed hydrocarbons (such as pyrene or coronene) yield some perhydro derivatives, but a part of the product consists of less completely reduced compounds with aromatic and olefinic features; these compounds are more resistant to further reduction than the parent hydrocarbons. ��� (iv) Condensed polynuclear hydrocarbons yield also some products containing hydroxyl (phenolic) and carbonyl groups.