Quality of Life and Screening on Body Dysmorphic Disorder, Depression, Anxiety in Septorhinoplasty

OBJECTIVES

Septorhinoplasty (SRPL) can improve quality of life (QoL) in functional and aesthetical aspects of the nose. A key factor compromising postoperative satisfaction is symptoms of body dysmorphic disorder (BDD), defined by excessive concerns and distress over slight or imagined physical defects. Although a high prevalence of BDD in SRPL patients is evident, the effect of positive screening on BDD and other psychiatric disorders is understudied. It was hypothesized that patients screening positive for BDD, depression or anxiety do not show increased postoperative QoL.

METHODS

A multicenter, prospective study including 259 patients. For psychiatric evaluation, the BDD concern questionnaire-aesthetic version and the Hospital Anxiety and Depression Scale were used; for disease-specific QoL the Rhinoplasty Outcomes Evaluation (ROE) and the Functional Rhinoplasty Outcome Inventory (FROI-17).

RESULTS

In preoperative evaluation, 32.5% had a positive screening for BDD, 42.2% for increased anxiety, and 32.9% for depression. Mean QoL improved in the whole cohort (FROI total score: 54.4 ± 21.8 to 32.8 ± 23.7 and ROE: 32.3 ± 15.6 to 69.8 ± 23.1, both p < 0.001). Patients screening positive for BDD, depression or anxiety did show an increased postoperative QoL, but to a significantly lower degree and with lower pre- and postoperative QoL levels.

CONCLUSIONS

SRPL patients show a high prevalence of BDD symptoms, elevated anxiety, and depression. These subgroups show lower QoL levels and an impaired QoL increase after surgery. Rhinoplasty surgeons must be aware of the disorders and their symptoms, discuss potential concerns with the patients, and potentially refer them to a specialist.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:2187-2193, 2024.

Treatment outcome of atypical EGFR mutations in the German National Network Genomic Medicine Lung Cancer (nNGM)

BACKGROUND

Atypical EGFR mutations occur in 10-30% of NSCLC patients with EGFR mutations and their sensitivity to classical EGFR-tyrosine kinase inhibitors (TKI) is highly heterogeneous. Patients harboring one group of uncommon, recurrent EGFR mutations (G719X, S768I, L861Q) respond to EGFR-TKI. Exon 20 insertions are mostly insensitive to EGFR-TKI but display sensitivity to exon 20 inhibitors. Clinical outcome data of patients with very rare point and compound mutations upon systemic treatments are still sparse to date.

PATIENTS AND METHODS

In this retrospective, multi-center study of the national Network Genomic Medicine (nNGM) in Germany, 856 NSCLC cases with atypical EGFR mutations including co-occuring mutations were reported from 12 centers. Clinical follow-up data after treatment with different EGFR-TKI, chemotherapy and immune checkpoint inhibitors were available from 260 patients. Response to treatment was analyzed in three major groups: (1) uncommon mutations (G719X, S7681, L861Q and combinations), (2) exon 20 insertions and (3) very rare EGFR mutations (very rare single point mutations, compound mutations, exon 18 deletions, exon 19 insertions).

RESULTS

Our study comprises the largest thus far reported real-world cohort of very rare EGFR single point and compound mutations treated with different systemic treatments. We validated higher efficacy of EGFR-TKI in comparison to chemotherapy in group 1 (uncommon), while most exon 20 insertions (group 2) were not EGFR-TKI responsive. In addition, we found TKI sensitivity of very rare point mutations (group 3) and of complex EGFR mutations containing exon 19 deletions or L858R mutations independent of the combination partner. Notably, treatment responses in group 3 (very rare) were highly heterogeneous. Co-occurring TP53 mutations exerted a non-significant trend for a detrimental effect on outcome in EGFR-TKI treated patients in groups 2 and 3 but not in group 1.

CONCLUSIONS

Based on our findings we propose a novel nNGM classification of uncommon EGFR mutations.

Development and validation of technologies suitable for the decontamination and re-use of contaminated N95 filtering facepiece respirators in response to the COVID-19 pandemic

Background

Coronavirus disease 2019 (COVID-19) has brought significant challenges to society globally, particularly in the area of healthcare provision. A pressing need existed in protecting those tasked with delivering healthcare solutions during the COVID-19 crisis by providing solutions for preserving adequate supplies of effective personal protective equipment (PPE).

Aim

To evaluate and validate available methods for the decontamination of N95 filtering facepiece respirators (FFRs) while maintaining functionality during re-use.

Methods

Multiple low-temperature steam and vaporized hydrogen peroxide (VHP) technologies were assessed for inactivation of Mycobacterium spp. and feline calicivirus (employed as representatives of the contamination challenge).

Findings

Virus (≥3log₁₀) and Mycobacterium spp. (≥6log₁₀) inactivation was achieved on various types of N95 FFRs using an array of heat (65–71^oC), humidity (>50% relative humidity) and VHP without affecting the performance of the PPE.

Conclusion

The methods have been validated and were authorized by the US Food and Drug Administration under a temporary emergency use authorization. Based on the findings, opportunities exist for development and deployment of decontamination methods made from simple, general purpose materials and equipment should a future need arise.

Frequency and risk factors of antibody-induced secondary failure of botulinum neurotoxin therapy

Objective

To investigate the risk factors of neutralizing antibody (NAB)–induced complete secondary treatment failure (cSTF) during long-term botulinum neurotoxin (BoNT) treatment in various neurologic indications.

Methods

This monocenter retrospective cohort study analyzed the data of 471 patients started on BoNT therapy between 1995 and 2015. Blood samples of 173 patients were investigated for NABs using the mouse hemidiaphragm test (93 with suspected therapy failure, 80 prospective study participants). The frequency of NAB-cSTF was assessed for various indications: hemifacial spasm, blepharospasm, cervical dystonia, other dystonia, and spasticity. A priori defined potential risk factors for NAB-cSTF were evaluated, and a stepwise binary logistic regression analysis was performed to identify independent risk factors.

Results

Treatment duration was 9.8 ± 6.2 years (range, 0.5–30 years; adherence, 70.6%) and number of treatment cycles 31.2 ± 22.5 (3–112). Twenty-eight of 471 patients (5.9%) had NAB-cSTF at earliest after 3 and at latest after 103 treatment cycles. None of the 49 patients treated exclusively with incobotulinumtoxinA over 8.4 ± 4.2 (1–14) years developed NAB-cSTF. Independent risk factors for NAB-cSTF were high BoNT dose per treatment, switching between onabotulinumtoxinA and other BoNT formulations (except for switching to incobotulinumtoxinA), and treatment of neck muscles.

Conclusions

We present a follow-up study with the longest duration to date on the incidence of NAB-cSTF in patients treated with various BoNT formulations, including incobotulinumtoxinA. Whereas the overall risk of NAB-cSTF is low across indications and BoNT formulations, our findings underpin the recommendations to use the lowest possible dose particularly in cervical dystonia, and to avoid unnecessary switching between different formulations.

[Epidemiological Study of the Effects of Gender, Age, Mobility and Time of Injury on Proximal Femoral Fractures]

PURPOSE OF STUDY Based on the selected criteria the study presents the evaluation of data of patients who underwent a surgery for proximal femoral fracture at the Department of Orthopaedic Trauma of the 1 st Faculty of Medicine and Military University Hospital Prague in the period 2013-2016. The paper aimed to determine whether there are any differences in proximal femoral fractures depending on the selected criteria. MATERIAL AND METHODS The study comprised 805 patients (562 women and 243 men) older than 21 years with proximal femoral fractures who were treated between January 1, 2013 and December 31, 2016. In the study, the patient s data on gender, age, a type of fracture (according to the AO classification), a level of mobility, time of injury and month of injury were analysed. The data was evaluated using the methods of descriptive statistics, one-way analysis of variance, two-way analysis by ANOVA and by following select POST-HOC test (Fisher LSD test) were utilized, 95% confidence interval was selected . RESULTS In the group of treated patients, the men were outnumbered by women (70% vs. 30%). In women the fractures occurred at a significantly (p < 0.001) older age (82 years) compared to men (77 years). Until the 8 th decade the fractures in men dominated, while from the 9th decade the fractures were more frequent in women. A sharp increase in the number of fractures in women was reported exactly in the 9th decade (56% of the total number of fractures in women). The group of women showed a significant difference (p = 0.027) between the age of femoral neck fractures and the age of trochanteric femoral fractures (80 years vs. 84 years). In both genders intracapsular and pertrochanteric fractures prevailed. In women and men with a limited mobility, fractures were sustained at the highest mean age (85 years in women, 84 years in men) compared to the other levels of mobility. In mobile patients, a significant difference (p < 0.001) was found between the age of women and men at which the fracture was sustained (79 years vs. 71 years). The largest significant difference (p < 0.001) in the age of fracture is seen in night time (84 years in women, 71 years in men). The highest number of injuries was suffered in the months of October to January, whereas the lowest number was reported in the period from June to July. DISCUSSION The epidemiological studies underline a notably higher incidence of proximal femoral fractures in women than in men, which was also confirmed by our study. The mean age of women with proximal femoral fracture was significantly higher compared to men. Similar conclusions have been drawn also by other studies. The incidence of fractures in dependence on the age group was the highest in women and men in their 9th decade, which compared to the previous studies was at a later age. This finding can be justified by aging of the Czech population, with the growing number of persons in the 9 th decade age group between 2012 and 2017 by 40,000. Nonetheless, men prevailed in fractures until the 9 th decade, while from the 9 th decade there is a marked growth in the number of these fractures sustained by women. This corresponds with the findings of other authors. As to the individual types of fractures (neck, trochanteric fracture) no difference was revealed in the percentage of women and men. In both genders intracapsular and petrochanteric fractures prevailed. Neither the level of pre-fracture mobility, nor the time of injury have been sufficiently monitored and evaluated with regard to the age of patients, therefore there is no adequate data to compare our results with. The lowest mean age at the time of injury was achieved by fully mobile men (71 years), which can be attributable to their sports and social activities performed at this age. The highest number of proximal femoral fractures was reported in the period from October to January, whereas their lowest number was reported in the period from June to July, which corresponds with the majority of other conducted studies in this area of research. CONCLUSIONS A considerably higher incidence of proximal femoral fractures in women was confirmed. The mean age of women with proximal femoral fracture was significantly higher than in men (82 vs. 77 years). Men prevailed in the number of fractures up to the 9 th decade, whereas from the 9 th decade the number of proximal femoral fractures in women significantly grew. In individual types of fractures (neck, trochanteric fractures), no difference in percentage of women and men was found. In both the genders intracapsular and pertrochanteric fractures significantly prevailed. The lowest mean age (71 years) at the time of injury was achieved by fully mobile men. The same age was identified in men also with respect to injuries sustained at night. The highest number of proximal femoral fractures was reported in the period from October to January, the lowest in the period from June to July. The knowledge of these seasonal variations can help plan the health care in the medical facility concerned. Key words: proximal femur, fracture, gender, mobility, day-time, seasonality.

Nucleotide sequence of the clustered genes for apocytochrome b6 and subunit 4 of the cytochrome b/f complex in the spinach plastid chromosome

A 2.4 kilobase-pair segment of the spinach plastid chromosome carrying the genes for apocytochrome b6 and subunit 4 of the thylakoid membrane cytochrome b/f complex has been analysed by DNA sequencing and Northern blot analysis. The nucleotide sequence reveals two uninterrupted open reading frames of 211 and 139 triplets coding for two hydrophobic proteins of 23.7 kd (cytochrome b6) and 15.2 kd (subunit 4). The genes are located on the same strand and are separated from each other by 1018 untranslated base pairs. They map adjacent to the gene for the P680 chlorophyll α apoprotein of the photosystem II reaction center. The three genes appear to be under common transcriptional control and the transcripts post-transcriptionally modified. The deduced amino acid sequences of cytochrome b6 and subunit 4 both exhibit significant homology with published sequences from mitochondrial b cytochromes (42 kd) suggesting that these functionally equivalent polypeptides in photosynthetic and respiratory electron transport chains arose monophyletically.

Additional binding mechanism of palonosetron to the 5-HT3 receptor versus first generation 5-HT3 receptor antagonists

19583

Background: Palonosetron has a higher binding affinity and longer plasma half-life than first generation 5-HT3 receptor antagonists. Clinical trials have demonstrated that a single intravenous dose of palonosetron 0.25 mg provides better protection from chemotherapy-induced nausea and vomiting than other 5-HT3 receptor antagonists throughout the 5-day post-chemotherapy period. The purpose of this work is to determine differences in the molecular interactions of the antagonists with the receptor that could help explain the clinical efficacy differences. Methods: Molecular ligand-receptor relationships for commonly used 5-HT3 receptor antagonists were investigated. In particular, competitive vs. potential allosteric interactions between ondansetron, granisetron and palonosetron and the 5-HT3 receptor were examined. Binding experiments were carried out using each unlabeled antagonist in competition with [3H]-antagonist. Concentrations of [3H]-antagonists used in these experiments included the equilibrium dissociation constant (Ki) and several-fold Ki values in an effort to represent the probable concentrations of each antagonist at the receptor site in vivo. The inhibitory concentration of unlabeled antagonist needed to observe half maximal binding (IC50) as a function of [3H]-antagonist concentration was plotted for comparisons between ondansetron, granisetron and palonosetron. Results: A plot of the concentration of unlabeled antagonist needed to observe IC50 as a function of [3H]- antagonist concentration was linear when ondansetron and granisetron were in competition. On the other hand, when palonosetron was in competition with either granisetron or ondansetron the plot was curvilinear in each case. Conclusions: These results indicate that palonosetron exhibits both competitive and allosteric interactions with the 5-HT3 receptor, in contrast to ondansetron and granisetron which display strictly competitive antagonism. As allosteric interactions may induce changes in the receptor conformation, we can speculate that palonosetron's dual action on the 5-HT3-receptor could induce amplification of its inhibitory effect at the primary receptor binding site.

No significant financial relationships to disclose.

Interleukin-1beta stimulates growth hormone-releasing hormone receptor mRNA expression in the rat hypothalamus in vitro and in vivo

Changes in growth hormone-releasing hormone (GHRH), GHRH-receptor (R), somatostatin and interleukin (IL)-1beta mRNA levels were determined in fetal rat hypothalamic cultures after administration of IL-1beta (1, 10, 100 ng/ml, 2 h incubation), and in adult rat hypothalamus 5 h after intracerebroventricular injection of IL-1beta (2.5 and 25 ng). IL-1beta stimulated GHRH-R mRNA expression both in vitro (10 and 100 ng/ml) and in vivo (2.5 and 25 ng). Somatostatin mRNA was significantly stimulated and GHRH mRNA slightly reduced in vitro, while these mRNA species were not altered in vivo in response to IL-1beta. IL-1beta stimulated its own expression both in vitro (10 and 100 ng/ml) and in vivo (25 ng). IL-1beta-induced mRNA responses occurred 2 h after treatment in vitro (incubation times, 30 min to 6 h). IL-1beta also elicited slight GHRH releases in vitro. Up-regulation of hypothalamic GHRH-R by IL-1beta may explain previous findings suggesting that IL-1beta stimulates GHRH activity.

[Value of endoanal sonography in the assessment of faecal incontinence]

PURPOSE

The aim of this study was to assess the value of endoanal ultrasound (EUS) in comparison to anal manometry and operative findings in patients suffering from faecal incontinence. Patient history, localisation of sphincter defects and therapeutic modalities were analysed.

METHODS

Over a 3-years period, 92 patients with faecal incontinence were investigated by endoanal ultrasound. Results were compared with anal manometry in 81 cases.

RESULTS

At EUS, 27 patients (29 %) showed no sphincter defect, 18 (20 %) had an isolated internal sphincter defect, 13 (14 %) an isolated defect of the external sphincter and 34 (37 %) presented with a combined internal/external sphincter defect. Manometry correlated in 30 % with endoanal ultrasound. Compared with surgery, endoanal ultrasound was correct in 100 % and manometry in only 54 %. An obstetric trauma was most frequently related to faecal incontinence.

CONCLUSION

Endoanal ultrasound is a very sensitive method for localizing anal sphincter defects and is mandatory in the assessment of patients with faecal incontinence.

Influence of photoperiod on N-acetyltransferase activity and melatonin in the fiddler crab Uca pugilator

Melatonin and N-acetyltransferase (NAT) activity were measured in the eyestalks of fiddler crabs acclimated to various photoperiods: constant light, a L:D 12:12 h photoperiod, or constant dark. Following acclimation, eyestalks were collected every 3 h over a 24-h period; they were assayed for melatonin with a radioimmunoassay and for NAT activity with a radioenzymatic assay. In constant light, melatonin levels increased at 1300 h, from 142 to 431 pg x mg(-1) eyestalk; NAT activity increased concurrently, from 97 to 203 pmol x h(-1) x mg(-1) eyestalk, and both remained elevated until 0400 h. In the L:D 12:12 h photoperiod, melatonin levels increased at 1300 h from 28 to 230 pg x mg(-1) eyestalk, and though NAT activity increased significantly, from 80 to 122 pmol x h(-1) x mg(-1) eyestalk, an even greater increase occurred at 0400 h, when melatonin levels were low. In constant dark, melatonin levels increased at 1600 h, from 22 to 196 pg x mg(-1) eyestalk, with a concurrent increase in NAT activity from 93 to 140 pmol x mg(-1) x h(-1) eyestalk. However, the second peak in melatonin (111 pg x mg(-1)), occurring at 0400 h, was out of phase with the second peak of NAT activity (113 pmol x mg(-1) x h(-1) eyestalk) which occurred at 0700 h. NAT may be a rate-limiting step in melatonin synthesis in fiddler crabs under some conditions (constant light and the 1300 h peak in constant dark); however, NAT activity correlates poorly with melatonin levels in a L:D 12:12 h photoperiod and in constant dark relative to the 0400 h melatonin peak.

HIV test counselling at a tertiary hospital

A questionnaire was distributed to 64 of the 78 interns working at a teaching hospital in Cape Town in August 1992 to examine their attitudes and practice in respect of HIV test counselling. The questionnaire was completed by 61 interns. Thirteen per cent of those who responded counselled all patients, 49% counselled some patients and 38% counselled no patients. Thirty-four per cent stated that they felt that pre-test counselling was always necessary and 57% that post-test counselling was always necessary. The most frequently stated reasons for not counselling patients were language barriers, time constraints, feelings of incompetence on the part of the intern and the fact that the patient was too ill. It is recommended that standard counselling procedures be established in each ward and formal under- and postgraduate counselling training for medical students and interns be instituted.

Spinach plastid genes coding for initiation factor IF-1, ribosomal protein S11 and RNA polymerase alpha-subunit

The nucleotide sequence of 2.5 kbp from the cloned SalI fragments 8 and 11 of spinach plastid DNA has been determined. This region was found to encode three open reading frames for hydrophilic polypeptides of 77, 138, and 335 amino acids. Using the computer search algorithm of Lipman and Pearson (Science 227, 1435, 1985), these genes were identified as coding for homologues of E. coli initiation factor IF-1 (inFA), 30S ribosomal protein S11 (rps11), and the alpha-subunit of DNA-dependent RNA polymerase (rpoA). The spinach plastid gene organization is inFA - 381 bp spacer - rps11 - 72 bp spacer - rpoA. The genes are transcribed in vivo and appear to encode functional proteins. These findings imply that plastid chromosomes code for components of the organelle transcription apparatus.

Localization of the gene for apocytochromeb-559 on the plastid chromosome of spinach

The gene for cytochromeb-559, associated with the photosystem II reaction center, has been located on the spinach plastid chromosome by cell-free coupled transcription-translation and RNA-programmed hybrid selection translation using appropriate recombinant DNAs, RNA fractions, and monospecific antisera. The gene is located in the large single-copy segment of the plastid chromosome between the genes for cytochomef and the P680 chlorophylla apoprotein of photosystem II and transcribed in the opposite direction relative to these genes. The 10 kd protein is decoded from a bicistronic 1.0 kb mRNA and is apparently not made as a precursor in cell-free rabbit reticulocyte andE. coli lysates.

Localization of the genes for the two chlorophyll a -conjugated polypeptides (mol. wt. 51 and 44 kd) of the photosystem II reaction center on the spinach plastid chromosome

A core particle of the water-oxidizing photosystem II reaction center has been prepared from stacked spinach thylakoid membranes by a procedure involving extraction with the non-ionic detergent dodecyl-beta-D-maltoside and centrifugation in sucrose gradients. The protein-pigment complex consists of at least four polypeptide species: two components with mol. wts. of 51 and 44 kd which are conjugated with chlorophyll a and beta-carotene, the herbicide-binding protein of mol. wt. 32 kd and cytochrome b 559 (11 kd). The genes for the 51-and 44-kd polypeptides have been located on the circular 150-kbp spinach plastid chromosome. They were identified by hybrid-selection mapping, in vitro transcription-translation of recombinant DNAs and specific antisera which were used to characterize the translation products. The plastid chromosome carries one uninterrupted copy for each of these genes in its large single-copy region. The gene for the 51-kd protein (which probably bears the P(680) reaction center chlorophyll a) is located in close proximity to the gene for cytochrome b6, and some 70 kbp away from the gene for the ;32-kd' herbicide-binding protein of the reducing side of photosystem II. The gene for the 44-kd protein is situated halfway between these two genes adjacent to the gene for the P(700) chlorophyll a apoprotein of the photosystem I reaction center. Both photosystem II genes are transcribed into discrete RNA species in the same direction but from the opposite strand as the gene for the ;32-kd' protein.

Genes and transcripts for the polypeptides of the cytochrome b6/f complex from spinach thylakoid membranes

Cytochrome b6/f complex was prepared from washed thylakoid membranes by a procedure involving detergent treatment and centrifugation in sucrose gradients. The complex is composed of at least four polypeptide species, cytochrome f which occurs in two variant forms (mol. wt. 34/33 kd), cytochrome b6 (23 kd), the high-potential Rieske iron-sulfur protein (19 kd) and a fourth subunit (17 kd) of unknown function. Transcripts for the cytochromes f, b6 and subunit 4 were found in plastid RNA, those for the Rieske iron-sulfur protein in cytosolic poly(A) RNA. Transcripts for cytochrome b6 and subunit 4 are translated in rabbit reticulocyte lysates into products of correct length. The Rieske iron-sulfur protein and the cytochrome f apoprotein appear to be made as precursors with excess sequences of 7 and 4 kd, respectively. Cytochrome f, cytochrome b6 and subunit 4 are encoded by uninterrupted plastid genes that are located in the large single-copy region of the circular DNA molecule. Each of these genes is present once per chromosome. Their location and direction of transcription have been determined by hybrid-selection mapping and by cell-free transcription/translation of various recombinant DNAs. The genes for cytochrome b6 and for subunit 4 lie near each other, but do not overlap. They are transcribed into a single message. The gene for cytochrome f maps 15 kbp away from this cluster, close to the 3' end of the gene for the large subunit of ribulosebisphosphate carboxylase/oxygenase, and is transcribed into a separate 4 kb long RNA. All these genes have the same polarities with respect to each other.

Genes and transcripts for the P700 chlorophylla apoprotein and subunit 2 of the photosystem I reaction center complex from spinach thylakoid membranes

A photosystem I reaction center complex has been purified to homogeneity by a procedure involving partial solubilization of spinach thylakoid membranes, ion exchange chromatography and centrifugation in sucrose gradients. The complex contains 7 polypeptides: the P700 chlorophylla apoprotein with an apparent molecular weight of 67 kd, which at high resolution splits into two bands, and smaller polypeptides of 22 (subunit 2), 18.5, 18, 16, 12 and 10 kd.Stable transcripts for the P700 chlorophylla apojprotein and subunit 2 were found in plastid and cytosolic RNA, respectively. The apoprotein product obtained by translation in a mRNA-dependent cell-free rabbit reticulocyte lysate and also by DNA-programmed transcription-translation of cloned plastid DNA fragments inE. coli lysates was indistinguishable immunologically and electrophoretically from the authentic protein. However, the product immunologically related to subunit 2 was 4 kd larger than the mature compound indicating that this protein is encoded in the nucleus and synthesized as a precursor.The gene for the P700 chlorophylla apoprotein has been physically mapped on the spinach plastid chromosome by hybrid selection mapping and DNA-programmed cell-free transcription-translation using cloned restriction fragments of plastid DNA. There is one gene copy per chromosome and it is located centrally in the large single-copy region of the circular DNA molecule. This gene is uninterrupted and is transcribed in the same direction as that of the large subunit of ribulose bisphosphate carboxylase/oxygenase. Its transcript is approximately 4 kb longer than the 2 kbp structural gene.

Characterization of an inducible amidase from Pseudomonas acidovorans AE1

The main molecular and catalytic properties of an acetanilide-hydrolyzing enzyme from Pseudomonas acidovorans AE 1, purified to a homogeneous state, were investigated. The molecular weight was 57 500 as determined by gel filtration and 55 300 as computed from the amino acid composition. By polyacrylamide gel electrophoresis in dodecylsulfate a polypeptide chain weight of 56 700 was obtained. Based on the reaction of the highly purufied enzyme with diethyl-4-nitrophenyl phosphate an equivalent weight of approximately 59 100 was found. From these results it was concluded that the enzyme consists of a single polypeptide chain and contains one active site per molecule. The enzyme hydrolyzed esters as well as certain aromatic amides. It also catalysed the transfer of acetyl groups to phenetidine yielding phenacetin. The activities towards aliphatic esters were much smaller. The enzyme was stable at pH values ranging from 7 to 9 and its pH-optimum was about 10. It was strongly inhibited by organophosphorous compounds, like diethyl-4-nitrophenyl phosphate or diisopropylphosphorofluoridate, as well as by physostigmine sulfate and -SH-blocking reagents, like HgCl-2 or 4-chloromercuribenzoic acid. o-Nitrophenol caused a competitive inhibition and phenetidine an uncompetitive inhibition.

Isolation of an inducible amidase from Pseudomonas acidovorans AE1

A bacterial strain, AEI, which hydrolysed acetanilide, was isolated from soil and identified as Pseudomonas acidovorans. Numerous amides, esters and enzyme inhibitors were tested as amidase inducers. Phenacetin was chosen as inducer for the large scale cultivation of these organisms because it was less toxic to the bacteria than acetanilide. The induction increased the enzymic activity 250-fold. In comparison, the type culture strain of P. acidovorans, ATTCCI5668, had no amidase activity which could be induced by phenacetin. Optimal growth conditions were established with respect to the concentration of carbon source and inducer so that about 10% of the extractable bacterial protein consisted of the amidase. The organisms were lysed with lysozyme in the presence of EDTA and the enzyme was isolated mainly by column chromatography procedures. A preparation form 60 g (wet wt) bacteria yielded about 100 mg highly purified amidase with a specific activity of 137 mugmol substrate hydrolysed/min/mg protien. In addition to acetanilide, the purified enzyme hydrolysed several other amides and esters. As standard substrate, p-nitroacetanilide was chosen.