The Clinicopathological and Prognostic Significance of HER2-Low Breast Cancer: A Comparative Analysis Between HER2-Low and HER2-Zero Subtypes

BACKGROUND

HER2-low breast cancer (BC) is a newly defined subset of HER2-negative BC. However, it is still uncertain whether HER2-low BC can be categorized as a distinct biological/clinical subgroup with any prognostic significance.

METHODS

Invasive BC cases (n = 10,215) with Stage I-III were retrospectively analyzed to determine the HER2 status. The HER2 status was then divided into 3 groups: HER2-0, HER2-low, and HER2-positive.

RESULTS

The HER2 status was classified as HER2-0 in 1,227 cases (12.0%), HER2-low in 7,209 cases (70.6%), and HER2-positive in 1779 cases (17.4%). HER2-low cases had more positive nodes and were significantly associated with positive ER/PgR, lower nuclear grade, and lower Ki-67 index. HER2-0 had the lowest OS rate in the primary cases and after recurrence. HER2-0 in the node positive group had the lowest OS and was significantly different from HER2-low in the same group. The pathological complete response (pCR) rate for NAC was lowest in the HER2-low group. The DFS after NAC was significantly better in all the pCR cases, regardless of the HER2 status. However, the DFS was significantly lower in the HER2-low non-pCR cases.

CONCLUSION

HER2-low accounted for 70% of the cases and correlated with favorable biological markers. The HER2-low group had a significantly better OS than the HER2-0 group. However, the response to NAC was low in the HER2-low group, and this group had the poorest prognosis among all the non-pCR cases. These findings indicate that HER2-low may have a different biology and prognosis and therefore should be classified as a new entity.

Long-term prognostic value of the GenesWell BCT score in Asian women with hormone receptor-positive/HER2-negative early breast cancer

BACKGROUND

Accurate prediction of the risk of recurrence is crucial for optimal treatment decisions in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative early breast cancer. The GenesWell BCT is a molecular assay to predict the 10-year risk of distant metastasis. In this study, we evaluated the long-term prognostic value of the GenesWell BCT assay.

METHODS

The BCT score was assessed in patients with HR-positive/HER2-negative early breast cancer who did not receive chemotherapy. We compared the 15-year distant metastasis-free survival (DMFS) between risk groups classified based on the BCT score. The risk of early (0-5 years) and late (5-15 years) recurrence was evaluated based on the BCT score classification.

RESULTS

According to the BCT score, 366 patients from Japan and Korea were categorized as BCT low risk (83.6%) and high risk (16.4%) for distant metastasis. Median follow-up time was 17.4 years. The 15-year DMFS rate was significantly lower in the BCT high-risk group (63.3%) than in the BCT low-risk group (93.6%) (P < 0.001). The BCT risk group was an independent prognostic factor for 15-year DMFS (hazard ratio, 4.59; 95% confidence interval 2.13-9.88; P < 0.001). Furthermore, the BCT score was a significant predictor of late recurrence (5-15 years) in patients aged ≤ 50 years and those aged > 50 years, and added prognostic information to traditional clinical prognostic factors.

CONCLUSION

The BCT score can identify patients at low risk for recurrence who may not require adjuvant chemotherapy or extended endocrine therapy, regardless of age.

Satisfaction of Patients Who Received Breast-Conserving Surgery Using the Suture Scaffold Technique: A Single-Institution, Cross-Sectional Study

BACKGROUND

Optimal cosmetic results after breast-conserving surgery (BCS) improve patient satisfaction. The suture scaffold technique (SST) is a breast reconstruction technique that all breast surgeons can perform without any extensive training in plastic surgery.

OBJECTIVE

We aimed to investigate patient satisfaction after BCS and compare blood loss and operative duration between the SST, breast glandular flap technique (BGFT), and no oncoplastic technique (NOT).

METHODS

This was a prospective, single-center, cross-sectional study. All patients who underwent BCS from August 2017 to September 2019 in our institution were included, with the exception of those with cT3 tumors or those who underwent nipple excision or bilateral breast surgery. The BREAST-Q™ was used to survey the patients, and the raw sum scale scores of the BREAST-Q™ were converted into BREAST-Q scores.

RESULTS

Overall, we identified 421 eligible patients. The NOT was used in 47 (11.1%) patients, the BGFT was used in 231 (54.8%) patients, and the SST was used in 143 (33.9%) patients. In the univariable model, the BGFT and the SST had higher BREAST-Q scores than the NOT, while in the multivariable model, the SST had significantly higher BREAST-Q scores than the NOT (ß = +7.7, 95% confidence interval [CI] 0.9-13.7; p = 0.01). Blood loss was significantly less with the SST compared with the BGFT (ß = -4.4, 95% CI -7.3 to -1.4), and there was no difference in operative duration between the methods.

CONCLUSIONS

Patient satisfaction with the SST was higher than with the NOT and was similar to the BGFT. The SST is an oncoplastic technique that all breast surgeons can perform and which requires comparable blood loss and operative duration in the NOT.

Abstract P3-18-13: A cross-sectional study to investigate association between oncoplastic techniques and patient satisfaction who received breast-conserving surgery

Background The suture scaffold technique (SST) is one of the oncoplastic techniques used for breast-conserving surgery (BCS), first reported in 2010. There is no report about the cosmetic outcome of SST, so we investigated SST patient satisfaction compared with other techniques. Method We started using the SST in August 2017. The SST requires the construction of scaffolds by using non-absorbable strings in the defect during BCS. The strings are pulled together and tied as close as possible without dimpling the skin from the superior to the inferior direction and medial to the defect's lateral direction. After approval by our institutional ethics committee in September 2020, we started a patient survey using the BREAST-QTM-BCT module (postoperative) version 2.0. We included the patients who received BCS from August 2017 to September 2019, except for cT3, patients who received nipple excision or bilateral breast surgery at our institution. The raw sum scale scores of BREAST-QTM were converted into one score that ranges from 0 (worst) to 100 (best). A score of 4 points is considered to be of minimal importance in breast reconstructive surgery. We utilized a multivariable linear regression model to identify the clinical factors associated with the score. The confounding variables included age, density of the breast, nipple-tumor distance, size of the tumor, location of the tumor, number of lymph nodes dissected, blood loss, and operative duration. Result We identified 437 eligible patients during the study period. Among them, 49 (11.7%) patients received no oncoplastic technique (NOT), 237 (56.8%) patients received mobilization technique of breast tissue (MTB), and 151 (36.2%) patients received SST. SST patients had a higher score than NOT and MTB patients in univariable analysis. In a multivariable model, SST patients had a significantly higher score than NOT (+7.1, 95%CI=0.5-13.0, p=0.03) and an equivalent score to MTB (+1.9, 95%CI=-1.9-5.8, p=0.32) patients. In addition, smaller tumors (+0.13; 95%CI=0.01-0.25) and cases with longer nipple-tumor distance (+1.1; 95%CI=0.24-1.9) showed significantly higher score. Conclusion Among patients who received BCS, the SST patients had higher satisfaction than NOT and equivalent satisfaction to MTB. Additional studies are needed to determine the indications and the limitations of this technique. Table. Multivariate logistic regression analyses for estimating the variables that may affect Rasch score who underwent BCS.

Multivariate logistic regression analyses for estimating the variables that may affect Rasch score.Rasch score95% CIp-valueOncoplastic techniqueNOT (49)0 (Reference)BMT (237)5.1-0.7~11.10.08SST (151)7.10.88-13.40.02NTD (cm)1.10.2-1.90.01Size of the tumor (mm)-0.13-0.25~-0.010.02

Citation Format: Reiko Mitsueda, Anri Gen, Yoshitaka Fujiki, Naomi Gondo, Mutsumi Sato, Junko Kawano, Koichi Kuninaka, Shuichi Kanemitsu, Megumi Teraoka, Yoshito Matsuyama, Shinichi Baba, Sugako Nomoto, Robert Sloan, Yoshiaki Rai, Yoshiaki Sagara, Yasuaki Sagara. A cross-sectional study to investigate association between oncoplastic techniques and patient satisfaction who received breast-conserving surgery [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-18-13.

Role of HER2-Related Biomarkers (HER2, p95HER2, HER3, PTEN, and PIK3CA) in the Efficacy of Lapatinib plus Capecitabine in HER2-Positive Advanced Breast Cancer Refractory to Trastuzumab

OBJECTIVE

The aim of this study was to investigate the correlation between human epidermal growth factor receptor 2 (HER2)-related biomarkers and the treatment outcomes using lapatinib plus capecitabine (LC) and to evaluate the influence of the estrogen receptor (ER) status in trastuzumab-refractory HER2-positive advanced breast cancer.

METHOD

Eighty patients were enrolled in this study. Total HER2, p95HER2, and total HER3 expression were quantified using the VeraTag assays. PTEN (phosphatase and tensin homolog) and p95 expression was evaluated using immunohistochemistry and PIK3CA mutation using direct sequencing.

RESULTS

The response rate to LC was 30%, clinical benefit rate was 51.3%, and the median progression-free survival (PFS) was 174.5 days. ER negativity significantly correlated with higher HER2 and p95HER2. The lower HER2 and PIK3CA mutations were often observed in the nonresponders. A high p95HER2 expression correlated with longer PFS especially in the high HER2- and ER-positive cases. Patients without the PIK3CA mutation showed longer PFS in the same subset. Overall survival after LC significantly correlated with the number of recurrence organs.

CONCLUSION

LC therapy is effective in trastuzumab-refractory HER2-positive breast cancer. Moreover, the biomarker expression differed depending on ER status, and a high p95HER2 expression and wild-type PIK3CA gene correlated with longer PFS especially in the ER-positive cases.

Abstract P4-21-25: The importance of hormone receptor status on biomarker expression and the efficacy of lapatinib plus capecitabine therapy after progression on trastuzumab in HER2 positive recurrent and advanced breast cancer

Background: Anti-HER2 treatment using trastuzumab (Tmab) has contributed to improving the clinical outcome of HER2-positive breast cancerpatients. However, some patients do not respond to Tmab therapy and the combination of Lapatinib and capecitabine (LC) is an effective treatment option after progression on Tmab. Hormone receptor status is also an important factor for deciding if the patient should be treated with endocrine therapy as well. The aim of this study was to investigate the clinical significance of hormone receptor status in biomarker expression and to evaluate the efficacy of lapatinib therapy.

Materials and Methods: Eighty patients with HER2 positive breast cancer refractory to Tmab were enrolled in this prospective trial (KBC-SG 1107) between December 2011 and March 2014. The following treatment began after enrollment; lapatinib 1250-mg tablets were administered orally once daily and capecitabine (2000 mg/m2 per day) on days 1 to 14 every 21 days until disease progression or until severe adverse events. Total HER2 (H2T), p95HER2 (p95), and total HER3 (H3T) expression levels were quantified in formalin-fixed paraffin embedded samples using VeraTag assays. ER and progesterone receptor (PgR), PTEN and p95 expressions were evaluated using immunohistochemistry (IHC) and PIK3CA mutation using direct sequencing. Statistical analyses were performed using SPSS (ver. 21). A two-sided P&lt;0.05 was considered a statistically significant difference.

Results: The ER- and PgR-positive rates were 55.0% and 33.8%, respectively. The response rate to LC was 30% (CR: 1 case; PR: 23 cases), the clinical benefit rate was 51.3% and the median progression-free survival (PFS) was 174.5 days. Both ER and PgR negativity significantly correlated with higher H2T (cutoff: 13.8), p95HER2 (cutoff: 2.8) and PTEN expression levels (cutoff: H score of 100). Lower H2T expression levels and PIK3CA mutation rates were often observed in the non-responders (both: p=0.087). The ER and PgR status did not correlate with response. A high p95 and PTEN expression significantly correlated with longer PFS in ER and/or PgR positive cases (p=0.02 and 0.03), respectively. The overall survival (OS) after LC significantly correlated with the number of recurrence organs (p=0.0002) but not with the p95 and PTEN expression levels.

Conclusion: LC therapy was effective in Tmab-refractory HER2 positive breast cancer. Moreover, the biomarker expression differed depending on the ER/PgR status and a high p95 and PTEN expression correlated with longer PFS in ER and/or PgR positive cases. Further study is necessary to validate these findings.

Citation Format: Arima N, Nishimura R, Toh U, Tanaka M, Saimura M, Okumura Y, Saito T, Tanaka T, Teraoka M, Shimada K, Koga T, Kurashita K, Todoroki H, Ueo H, Ohi Y, Toyoshima S, Mitsuyama S, Tamura K. The importance of hormone receptor status on biomarker expression and the efficacy of lapatinib plus capecitabine therapy after progression on trastuzumab in HER2 positive recurrent and advanced breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-25.

Efficacy and Safety of Salmeterol/fluticasone Combination Therapy in Infants and Preschool Children with Asthma Insufficiently Controlled by Inhaled Corticosteroids

BACKGROUND

Clinical evidences of inhaled salmeterol/fluticasone propionate combination (SFC) therapy are insufficient in early childhood asthma.

OBJECTIVES

To examine the effects of SFC50, a combination product of salmeterol xinafoate (50 μg/day) and fluticasone propionate (100 μg/day), in infants and preschool children with asthma.

METHODS

The study was conducted at 31 sites in Japan. 35 patients (6 months to 5 years old) with asthma insufficiently controlled by inhaled corticosteroids (100 μg/day) were initiated to treat with SFC50 twice a day for 12 weeks with pressurized metered dose inhalers. The efficacy of SFC50 was assessed using nighttime sleep disorder score as the primary endpoint and the other efficacy measurements. The safety measurement included the incidences of adverse event (AE).

RESULTS

Mean patient age was 3.1 years, and 94.2% had mild-to-moderate persistent asthma (atopic type: 65.7%). Nighttime sleep disorder scores, assessed by a nighttime sleep diary, significantly decreased after treatment with SFC50 throughout the study period (p<0.01). SFC50 also significantly improved other efficacy outcomes including asthma symptom score, frequency of short-acting beta-agonist treatment, frequency of unscheduled visits to clinic, frequency of exacerbation due to virus infection, asthma control score and patient QOL score (p<0.01). AEs of cold, upper respiratory inflammation and asthmatic attack occurred in each of the 3 patients (8.6%); however, these were not regarded as treatment-related AEs.

CONCLUSIONS

SFC50 improved nighttime sleep disorder score and other efficacy outcome measures with no safety concerns. The results suggest that SFC50 treatment is useful to control the mild-to-moderate asthma in infant and preschool-aged children.

A case of femoral diaphyseal fracture after long-term treatment with zoledronic acid

We report here a case of femoral diaphyseal fracture thought to be caused by oversuppression of bone remodeling due to long-term bisphosphonate treatment. The patient was a 63-year-old postmenopausal woman. She had undergone left lumpectomy and sentinel node biopsy for left breast cancer at age 57. The case was diagnosed as pT2N0M0, stage IIA breast cancer. The biopsy sample was positive for hormone receptors and negative for HER2 protein. Postoperatively, exemestane was administered as adjuvant therapy. Right axillary lymph node metastasis was found at age 59, and right axillary lymph node dissection was performed. Postoperatively, epirubicin/cyclophosphamide and paclitaxel were administered. Subsequently, letrozole was administered. However, bone metastases to the first thoracic vertebra and right ilium were found at age 60, and zoledronic acid administration (4 mg/month) for bone metastasis was initiated. The patient developed a transverse fracture in the proximal left femoral diaphysis when she walked on a flat surface after zoledronic acid was administered for 2 years, 10 months. She was treated with an intramedullary nail for left femoral diaphyseal fracture. Cancellous bone of the medullary cavity was histopathologically examined, but there were no metastatic lesions from the breast cancer and no osteoblasts or osteoclasts were observed. Zoledronic acid was immediately discontinued in this patient. In recent years, cases of atypical femoral diaphyseal fractures caused by minor trauma in patients undergoing long-term bisphosphonate treatment have been reported. Thus, careful observation is required for patients who are anticipating bisphosphonate treatment.

Maternal origin of a unique extra chromosome, der(9)(pter-->q13::q13-->q12:) in a girl with typical trisomy 9p syndrome

We report on a girl with the typical trisomy 9p syndrome who had an additional E-sized metacentric chromosome. On the basis of GTG- and CBG-banding, her karyotype was considered to be 47,XX,+der(9)(pter-->q13::q13-->q12:) de novo. Results of a fluorescence in situ hybridization study using a chromosome 9-specific painting probe were compatible with this cytogenetic interpretation. Molecular analyses of six highly polymorphic dinucleotide repeat loci on the short arm and the proximal long arm of chromosome 9 demonstrated that the girl inherited one allele from her father and two identical or different alleles from the mother. We speculated that the extra chromosome may have resulted from either nondisjunction of chromosome 9 followed by a U-type exchange and a crossing-over between different sister chromatids during maternal meiosis I and subsequent breakage and malsegregation during meiosis II, or nondisjunction during meiosis II followed by isochromosome formation in one of the two maternal chromosomes 9 and subsequent breakage.

Rapid screening method to detect mutations in CYP21, the gene for 21-hydroxylase

To facilitate a rapid and practical molecular diagnosis of 21-hydroxylase deficiency (21-OHD), we developed a polymerase chain reaction (PCR) test in which only the 21-OH gene (CYP21) is amplified. We applied the test to diagnose 23 patients with salt-wasting type of 21-OHD. The upstream and downstream sequences of CYP21 have been specifically amplified by using a primer set containing the 8-bp deletion sequence of exon 3, which is distinct from its pseudogene CYP21P. The amplified PCR products were further subjected to mutation detection by restriction analysis: E1PL by AciI, I2g by PstI, E63a by DraIII, E7VL by ApaLI, E8non by PstI, and E8RW by AciI. To detect delections and/or gene conversions occurring on exon 3, we used the method described by Rumsby and Honour [1990: J Med Genet 27:676-678]. Our method is able to elucidate 8 common CYP21 mutations by using only 3 primer pairs and 4 restriction enzymes. The overall detection ratio of abnormal haplotypes by this method was over 95%, indicating that our method is practical and useful, particularly for carrier detection.

A novel mutation (296 del G) of the SOX90 gene in a patient with campomelic syndrome and sex reversal

The human SOX9 gene is responsible for the campomelic syndrome (CMPS) and sex reversal. This gene encodes a transcription factor containing a DNA binding domain homologous to the SRY high mobility group (HMG) domain. A novel mutation of SOX9, i.e. a single G deletion in one allele at nt 296 from A of the first ATG in the open reading frame, was identified in a patient with CMPS with sex reversal. The deletion resulted in a frameshift mutation upstream of the HMG box and a stop codon 30 bp downstream of the HMG box. The predicted truncated SOX9 protein contained 108 amino acids instead of the 509 amino acids of the normal SOX9 protein, removing nearly 80% of the SOX9 protein, including the HMG and the C-terminal transactivation domain. Most patients with CMPS reported previously died within the neonatal period. Our findings that the patient has survived, although has been in daily need of mechanical ventilation support for 5 years and 3 months despite a severely impaired SOX9 protein, do not support a linear relationship between the type of mutation and severity of the clinical outcome.

Two novel mutations of SURF1 in Leigh syndrome with cytochrome c oxidase deficiency

Cytochrome c oxidase (COX) deficiency is the most common cause of Leigh syndrome (LS). COX consists of ten nuclear-encoded and three mtDNA-encoded structural subunits. Although the nucleotide sequences of all 13 genes are known, no mutation was found in nuclear-encoded subunit genes of COX-deficiency patients. Zhu et al. (1998) and Tiranti et al. (1998) found nine mutations in the surfeit 1 (SURF1) gene in LS families with COX deficiency. The mouse surfeit gene cluster consists of six closely spaced housekeeping genes unrelated by sequence homology. Except for the Surf3 gene, the function is still not known. The juxtaposition of at least five of the surfeit genes is conserved between birds and mammals. We identified two novel mutations of SURF1 in a Japanese LS patient with COX deficiency using direct sequencing analysis. Firstly, a 2-bp deletion at nucleotide position 790 (790delAG) in exon 8 was found, which shifts the reading frame such that the mutant protein has a completely different amino acid sequence from codon 264 to the premature stop codon at 290. Secondly, we found a T-to-G transversion at nucleotide 820, resulting in the substitution of tyrosine by aspartic acid at codon 274 (Y274D). We also studied the parents' genes, and found that the Y274D mutation was in his father and the 790delAG mutation was in his mother heterozygously. Therefore, we concluded that the patient was a compound heterozygote with these mutations. These are the first pathogenetic SURF1 mutations identified in a Japanese family.

Identification of a transcriptional activator (ChnR) and a 6-oxohexanoate dehydrogenase (ChnE) in the cyclohexanol catabolic pathway in Acinetobacter sp. Strain NCIMB 9871 and localization of the genes that encode them

We identified chnR, a gene encoding an AraC-XylS type of transcriptional activator that regulates the expression of chnB, the structural gene for cyclohexanone monooxygenase (CHMO) in Acinetobacter sp. strain NCIMB 9871. The gene sequence of chnE, which encodes an NADP(+)-linked 6-oxohexanoate dehydrogenase, the enzyme catalyzing the fifth step of cyclohexanol degradation, was also determined. The gene arrangement is chnB-chnE-chnR. The predicted molecular masses of the three polypeptides were verified by radiolabeling by using the T7 expression system. Inducible expression of cloned chnB in Escherichia coli depended upon the presence of chnR. A transcriptional chnB::lacZ fusion experiment revealed that cyclohexanone induces chnB expression in E. coli, in which a 22-fold increase in activity was observed.

45,X/46,X,idic(Yq) mosaicism: clinical, cytogenetic, and molecular studies in four individuals

45,X/46,X,idic(Yq) mosaicism is associated with a variety of sex phenotypes, including Ullrich-Turner syndrome (UTS), intersexuality, and complete male. It remains unclear whether the phenotypic variability results from a dilutional effect by the 45,X cell line in the primordial gonad or an abnormality of the SRY gene (SRY). We conducted cytogenetic and molecular studies on four patients with such mosaicism, two of whom had a complete male phenotype and two who had UTS. Chromosome analyses showed that the frequency of cells carrying an idic(Yq) chromosome in peripheral blood lymphocytes and skin fibroblasts was not related to the given sex phenotype. The SRY, PABY, and ZFY genes were present in all four patients. A fluorescence in situ hybridization (FISH) study showed that both a patient with a complete male phenotype and another with UTS had duplicate copies of SRY in their idic(Yq) chromosomes, whereas a patient with UTS had a single copy of the gene. These findings suggested that the coexisting 45,X cell line is more influential on the determination of the sex phenotype in individuals with 45,X/ 46,X,idic(Yq) mosaicism.

[Histological study of the tracheal adventitia, perichondrium and annular ligament]

The trachea begins at the lower border of the cricoid cartilage and passes down to bifurcate into the left and right mainstem bronchi. The presence of tracheal invasion is crucial factor influencing the prognosis for patients with cancers of the thyroid gland, hypopharynx, esophagus, etc. In order to understand the manner of invasion of the above tumors, precise knowledge of the normal tracheal structure is indispensable. This study was undertaken to clarify the normal microscopic structure of the trachea. Five normal tracheal specimens obtained at surgery were examined histologically and immunohistochemically. The loose connective tissue around the trachea, known as adventitia, was divided into a loose outer and a dense inner layer by hematoxylin and eosin (HE) staining. This two-layer pattern was clearly seen near the annular ligament but was obscured away from it. The connective tissue of the inner layer ran obliquely to joint the connective tissue of the annular ligament and ended in the submucosal layer. This arrangement of connective fibers seems to play a role in allowing the trachea to stretch and bend. Tracheal cartilage is covered with a dense fibrous membrane known as the perichoundrium. Between the superficial fibrous membrane and mature cartilage cells lies zone of immature cartilage made up of oval or spindle cells, and the inclusion of this zone in the perichondrium has long been a subject of controversy. In our study, the zone was homogeneously stained red by the elastica van Gieson's stain and was clearly distinguished from other structures. Immunohistochemical staining revealed a wide distribution of type I and type III collagen on the fibrous membrane and the zone of immature cartilage cells, while mature cartilage cells did not show such collagen. Based on these findings, we conclude that the zone of immature cartilage cells belongs to the periochondrium, which thus contains two layers, an outer fibrous layer and an inner transitional layer of immature cartilage cells. Our conclusions are as follows: 1. Tracheal adventitia is divided into two layers, an outer loose and an inner dense fibrous layer. 2. Tracheal perichondrium also consists of two layers, an outer fibrous layer and an inner transitional layer. 3. The fibrous bundle originating from the adventitia joins the connective tissue of the annular ligament, probably in order to allow the trachea to stretch and bend.

Properties of poly(3-hydroxybutyrate) depolymerase from a marine bacterium, Alcaligenes faecalis AE122

Alcaligenes faecalis AE122 that used poly(3-hydroxybutyrate) (PHB) as a sole source of carbon was newly isolated from a coastal seawater sample. The strain required seawater for growth on PHB as well as in a nutrient broth, in which seawater could be replaced by an appropriate concentration of NaCl. PHB depolymerase was purified to homogeneity from the culture supernatant of A. faecalis AE122 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme consisted of a monomer subunit with a molecular mass of 95.5 kDa. The N-terminal amino acid sequence was GAWQNNLAGGFNKV. The dimeric and trimeric esters of 3-hydroxybutyrate were the main hydrolysis products of the purified enzyme. The enzyme was most active at pH 9.0 and 55 degrees C and was inhibited by phenylmethylsulfonyl fluoride. Several cations in seawater greatly enhanced the enzyme activity.

[Clinical efficacy of arbekacin in patients with methicillin-resistant Staphylococcus aureus infections. Research Group of MRSA Forum]

We investigated the clinical efficacy of arbekacin (ABK) in patients with methicillin-resistant Staphylococcus aureus (MRSA) infections, and also studied coagulase types, beta-lactamase producing activity and drug sensitivity of MRSA isolated from various clinical specimens. A total of 23 patients with MRSA infections (13 cases of pneumonia, 1 case of sepsis, 1 case of pneumonia and sepsis and 8 cases of the others) who were hospitalized from April 1992 to September 1993 were enrolled in this study. They were 14 males and 9 females, and the mean age was 66.9 years (range, 18-91 years). All patients had underlying diseases (mainly malignant tumors and cerebrovascular diseases). ABK was given intravenously at doses ranging from 75 to 100 mg twice daily. The clinical efficacy rate was 90%; 8 cases showed excellent responses, 10 cases good, 1 case fair, 1 case poor and 3 cases were unevaluable. The eradication rate of MRSA was 81.8%; 16 cases were judged as eradicated, 3 cases decreased, 2 cases replaced, 1 case unchanged and in 1 case the bacteriological response was unknown. Side effects were not observed, but S-GPT was elevated in 1 case. Coagulase types of MRSA (123 strains) isolated at the institutes involved in the study were type II (56 strains), type IV (12 strains), type VII (13 strains) and other types (2 strains), but coagulase types of 40 strains could not be determined. Eighty-four strains (68.3%) produced beta-lactamases. MICs of ABK were 0.5 microgram/ml against 43 strains and 1 microgram/ml against 37 strains, and all of the MICs were under 4 micrograms/ml. In summary, ABK showed high antimicrobial activity against MRSA and clinical usefulness in the infections investigated.

Synthesis and deposition of spore coat proteins during sporulation of Bacillus megaterium

Rabbit (anti-spore coat protein) IgG was prepared by immunization with coat proteins extracted with sodium dodecyl sulfate and dithiothreitol from isolated spore coats of Bacillus megaterium ATCC 12872. Coat proteins were detected from 3 hr after the end of exponential growth (t3) in the mother cell cytoplasmic fraction by sandwich enzyme immunoassay using this antibody. The proteins in the forespore coat protein fraction increased from t3 and reached a plateau at t10. Immunoblot analysis for the coat proteins in sporulating cells revealed the sequential synthesis of various proteins in the mother cell cytoplasmic fraction and simultaneous deposition of the same proteins as in the forespore coat fraction. These results suggest that turnover of precursor proteins of the spore coat is very rapid if precursor proteins are produced and they are proteolytically processed to produce mature proteins. Specific antibody to the 48,000-dalton protein, which is a major protein, did not cross-react with any other major (36,000, 22,000, 19,500, and 17,500-dalton) proteins. Specific antibody to the 22,000-dalton protein did not cross-react with the 48,000, 36,000, 19,500, 17,500, and 16,000-dalton proteins, but did cross-react with the 44,000, 25,000, and 12,000-dalton proteins.