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Background: Hyponatremia is a common complication following endoscopic endonasal resection (EER) of pituitary adenomas. We report a single-center, multisurgeon study detailing baseline clinical data, outcomes, and factors associated with postoperative hyponatremia., Methods: This was a retrospective cohort study of patients undergoing EER for pituitary adenoma at Tufts Medical Center. Most procedures were performed by the senior author (C.B.H.). Cases were included if at least 1 postoperative sodium value was available and pathology confirmed pituitary adenoma. Hyponatremia was defined as a postoperative sodium level <135 mEq/L., Results: A total of 272 patients underwent 310 EER procedures that met the study inclusion criteria. The mean patient age was 53.3 years, and mean tumor size was 18.8 mm. Postoperative hyponatremia occurred in 12.6% of cases, with 3.6% developing hyponatremia prior to discharge. Lower preoperative sodium level was associated with an increased risk of developing any postoperative hyponatremia. Older age, prolactinoma pathology, and use of selective serotonin reuptake inhibitors were associated with moderate to severe hyponatremia (≤129 mEq/L), and lower preoperative sodium was associated with mild hyponatremia (130-134 mEq/L). Hyponatremia-related readmissions within 30 days occurred in 3.9% of patients. Both African-American race and postoperative hyponatremia were associated with an increased risk of 30-day readmission. The mean nadir sodium for hyponatremic patients was 129.9 mEq/L. Growth hormone-secreting pathology was associated with lower postoperative nadir sodium, whereas higher preoperative sodium was associated with higher postoperative nadir sodium., Conclusions: Hyponatremia is a common postoperative complication of EER for pituitary lesions that can cause significant morbidity, increased readmissions, and increased healthcare costs., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Recent trials have demonstrated clinical benefits to a combined orthoplastic approach for complex reconstructive surgery of the hand, upper and lower extremity., Purpose: We sought to assess recent trends in exposure to orthoplastic-type procedures among plastic surgery residents training in the United States., Methods: Independent plastic surgery residents' case logs were extracted from the Accreditation Council for Graduate Medical Education (2011-2022). Select reconstructive procedure were taken as proxies for orthoplastic-type cases and analyzed by descriptive statistical analysis., Results: The average number of orthoplastic-type cases completed per resident per year increased from 168.2 to 189.2 (12.5% increase) between 2011-2022. The greatest increase was in exposure to peripheral nerve injury repair of the hand and upper extremity (22.6 to 39.1, 73% increase). As a proportion of total procedures during the study period, orthoplastic-type procedures remained relatively unchanged (range 9.5-10.4%)., Conclusions: Our findings suggest that plastic surgery residents may be increasingly well-prepared to contribute to orthoplastic care during and following their training. The steady proportion of cases that orthoplastic-type procedures represented over the study period suggests the increase in relevant orthoplastic case volume may be incidental and secondary to an overall rise among all procedures. Given evidence of the benefits of an orthoplastic approach, we recommend consideration of explicit benchmarks for orthoplastic training among plastic surgery residents., (Copyright © 2024 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Quantum dots (QDs) have been widely used for bioimaging in vivo because of their excellent optical properties. As part of the preparation process of QD-based nanohybrids, purification is an important step for minimizing contaminants and improving the quality of the product. In this work, we describe high-performance size exclusion chromatography (HPSEC) used to purify nanohybrids of CdSe/ZnS QDs and anti-human epidermal growth factor receptor 2 antibodies (QD-HER2-Ab). The unbound antibody and suspended agglomerates were removed from freshly prepared QD-HER2-Ab via HPSEC. Pure and homogeneous QD-HER2-Ab were then used as immunofluorescence target imaging bioprobes in vivo. The QD-HER2-Ab did not cause any obvious acute toxicity in mice one week after a single intravenous injection of 15 nmol/kg. The purified QD-HER2-Ab bioprobes showed high tumor targeting ability in a human breast tumor xenograft nude mouse model (24 h after injected) with the possibility of in vivo immunofluorescence tumor imaging. The immunofluorescence imaging background signal and acute toxicity in vivo were minimized because of the reduction of residual QDs. HPSEC-purified QD-HER2-Ab is an accurate and convenient tool for in vivo tumor target imaging and HER2 detection, thus providing a basis for the purification of other QD-based bioprobes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objective: Primary spinal cord astrocytomas are rare, fatal, and poorly studied., Methods: This study included a 2-center, retrospective analysis of primary spinal cord astrocytoma patients from 1997 to 2020. Patients with drop metastases or without at least one follow-up were excluded., Results: Seven World Health Organization grade I, 6 grade II, 7 grade III, and 4 grade IV astrocytoma patients were included. Older patients had higher grades (median 20 years in grade I vs. 36.5 in grade IV). The median follow-up was 15 months. Thirteen patients were discharged to rehabilitation. Eight patients demonstrated radiographic progression. Adjuvant therapy was utilized more in higher grades (5 of 13 grades III vs. all 11 grades IIIIV). Six patients died (1 death in grades III vs. 5 in grades IIIIV). Ten patients had worsened symptoms at the last follow-up. The median progression-free survival in grade I, II, III, and IV tumors was 116, 36, 8, and 8.5 months, respectively. The median overall survival in grade I, II, III, and IV tumors was 142, 69, 19, and 12 months, respectively. Thrombotic complications occurred in 2 patients, one with isocitrate dehydrogenasewild type glioblastoma., Conclusions: Outcomes worsen with higher grades and lead to difficult postoperative periods. Clinicians should be vigilant for thromboembolic complications. Further research is needed to understand these rare tumors., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: In previous plastic surgery residency match cycles, in-person activities at other institutions, such as away rotations, have facilitated matches outside of an applicant's home program or region. The COVID-19 pandemic, however, limited these in-person opportunities. Therefore, we hypothesized that applicants of the 2021 cycle would be more likely to match into programs with which they have existing geographic connections when compared to previous years., Design: Residency websites and social media accounts were searched for resident names and educational information for those matching in 2021 and 2015 to 2020. Outcomes included proportion of applicants matching at the program affiliated with their medical school ("home program"), or matching in the same state or United States Census Map region as their medical school or undergraduate institution. Subgroup analyses were stratified by program region, incoming resident class size, and Doximity residency reputation ranking., Setting: Columbia University (New York)., Participants: For the 2015 to 2020 residency cycles, 963 residents were identified from 78 (95.1%) programs. For 2021, 159 incoming interns were identified from 70 (82.3%) programs., Results: 2021 applicants matched into their home program at higher rates than 2015-2020 applicants (36.0% vs. 24.1%, p  = 0.019). This trend was similar regardless of program region or size. This increase was significant for programs ranked outside of the top 30 (41.5% vs. 26.4%, p = 0.032), but not for the top 30 programs (32.1% vs. 22.3%, p = 0.128). Excluding those who matched at their home program, 2015 to 2020 and 2021 applicants matched in the same state or region of their medical school or undergraduate institution at similar rates (p > 0.05 for all)., Conclusions: During the COVID-19 pandemic, plastic surgery residency programs matched more applicants from affiliated medical schools than in previous years. This may result from lack of in-person opportunities for applicants at other programs. Alternative relationship-building opportunities may facilitate broader geographic connections in the 2022 cycle., (Copyright © 2021 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.)

Objectives: Initially treating vestibular schwannomas (VSs) with subtotal resection (STR) followed by Gamma Knife radiosurgery (GKRS) for progression of tumor residual is a strategy that balances maximal tumor resection with preservation of neurological function. The effect of timing of GKRS for residual and recurrent VSs remains poorly defined. We developed a simple and practical treatment algorithm for the timing of GKRS after STR of VSs and reviewed our follow-up results to determine outcomes between patients treated with early vs. late GKRS., Patients and Methods: Patients that underwent STR between 1999 and 2017 for a VS at Tufts Medical Center were identified and included in the study cohort. Patients who received GKRS ≤ 12 months after STR were included in the early intervention group. Patients who received GKRS > 12 months after STR or did not have tumor progression on follow-up thus not requiring GKRS were included in the observation/delayed intervention group., Results: STR of VSs was performed on 23 patients. Mean patient age at the time of STR was 53.0 years (range: 20-86.2). The mean follow-up was 4.2 years (range: 1 month-15.5 years). Patients most frequently presented with hearing loss. There were 5 patients (21.7 %) in the early intervention group and 18 (78.3 %) patients in the observation/delayed intervention group. Ten of 23 patients (43.5 %) required GKRS. Thirteen (56.5 %) did not receive GKRS. None of the patients in the early intervention group or the observation/delayed intervention group had changes in House-Brackmann (HB) Grade either after GKRS or at the end of the study period., Conclusions: GKRS of residual or recurrent tumor is safe following STR of VS and appears to carry a low risk of worsening facial nerve function when performed for progressive tumor growth., (Copyright © 2020. Published by Elsevier B.V.)

Due to excellent optical properties, quantum dots (QDs) have been widely applied to sensing, labeling, and imaging. For the fabrication of QD-based bioprobes, purification is usually the crucial step. Hydrophilic octylamine grafted polyacrylic acid modified QDs (OPA-QDs) were prepared, and purified by high-performance size exclusion chromatography (HPSEC) to remove excess OPA and aggregated QDs. The percentage of suspended agglomerates of OPA-QDs in the unpurified OPA-QDs increases from 4% to 31% through a year, but the purified OPA-QDs of the same batch possess excellent colloidal stability for at least one year. Subsequently, QD-based bioprobes were fabricated by the conjugation between QDs and streptavidin (SA) or antibody (IgG), generating QD-SA and QD-IgG, respectively, which were purified via HPSEC. Finally, the resulting QD-SA and QD-IgG were adopted to detect tumour markers on slices and showed specific positive signals without nonspecific adsorption, which was contrary to the unpurified QD-IgG. Thus, the HPSEC-coupled system proposed in the current work is potent and universal for the generation of purified and monodisperse QD-based bioprobes, which is promising in the nanobiodetection field., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This study developed an affinity-gradient nano-stationary phase (AG-NSP) for protein analysis using nanofluidic capillary electrochromatography (nano-CEC) conjugated with matrix assisted laser desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS). The AG-NSP can be used for protein pre-separation in nano-CEC and as a matrix carrier for protein analysis in MALDI-TOF-MS. A hydrophobicity gradient in AG-NSP was photochemically formed by grafting 4-azidoaniline hydrochloride on vertically arrayed multi-wall carbon nanotubes (MWCNTs) through gray-level exposure to UV light. The reversed-phase gradient stationary phase in AG-NSP was tailored according to the properties of the mobile phase gradient in capillary electrochromatography. As a result, the operation of the system is easily automated using a single buffer solution without the need for multiple solvents for elution. The use of nano-CEC with AG-NSP demonstrated excellent separation efficiency and high resolution for various types of DNA/protein/peptide. MALDI-TOF-MS analysis was then performed directly on the separated proteins and peptides on the chip. The proposed system was then used for the detection of three types of proteins with different molecular weights and PI values, including Cytochrome c (12,360, pI = 10), Lysozyme (14,300, pI = 11), and BSA (86,000, pI = 5)), and digested IgG fragments. The proposed system provided resolution of 1000 Da for the proteins in this study and the separation of digested IgG fragments at a low concentration of 1.2 pmol μL(-1)., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Infantile hemangiomas (IHs) spontaneously involute, but some leave contour deformities necessitating surgical correction. There is a paucity of data reviewing predictive risk factors associated with a need for surgery to guide clinicians when counseling parents. Patients undergoing IH resection by a single surgeon from August 2004 to August 2011 were reviewed to determine patient (age, gender, birth history) and IH characteristics (size, location) associated with surgical intervention. Data were compared to published data from the Hemangioma Investigator Group (HIG). Statistical analysis was performed using Student's t-test, odds ratio, and logistic regression analysis. Out of 196 referred patients, 112 underwent surgery. There was a female preponderance (3.5:1). Two-thirds of patients (64.9%) first presented to the surgeon at ≤2 years of age, but most underwent surgery between 2 and 3 years (52.7%; average lag time, 11 months). 18 patients underwent surgery at ≤1 year of age. IH patients with preterm birth history had increased risk for needing surgical intervention (odds ratio 2.124, CI 1.31-3.44; p < 0.0012). A majority (84.7%) of resected IHs were located on the head or neck, significantly higher than the distribution from the HIG data (62.2%; p < 0.0001). Resected head and neck IHs were smaller than those below the neck (average, 8.85 cm(2) vs. 22.35 cm(2), p = 0.017). Preterm birth is associated with higher risk for requiring surgical intervention. IHs on the head and neck are more likely to be removed when compared to those below the neck, and at a smaller size threshold., (Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Purpose: To identify various dosimetric parameters of bone marrow cavity that correlate with acute hematologic toxicity (HT) in patients with anal squamous cell carcinoma treated with definitive chemoradiation therapy (CRT)., Methods and Materials: We analyzed 32 patients receiving CRT. The whole pelvic bone marrow (PBM) and the lumbosacral spine (LSS) subregion were contoured for each patient. Marrow cavities were contoured using the Hounsfield units (HUs) of 100, 150, 200, and 250 as maximum density threshold levels. The volume of each region receiving at least 5, 10, 15, 20, 30, and 40 Gy was calculated. The endpoint was grade ≥3 HT (HT3+). Normal-tissue complication probability (NTCP) was evaluated with the Lyman-Kutcher-Burman (LKB) model. Maximal likelihood estimate was used to compare the parameter set. Logistic regression was used to test associations between HT and both dosimetric and clinical parameters., Results: Ten patients (31%) experienced HT3+. While dose to both LSS and PBM significantly predicted for HT3+, LSS was superior to PBM by logistic regression and LKB modeling. Constrained optimization of the LKB model for HT3+ yielded the parameters m = 0.21, n = 1, and TD50 = 32 Gy for LSS. The NTCP fits were better with the whole bone than with marrow cavity using any HU threshold. Mean LSS doses of 21 Gy and 23.5 Gy result in a 5% and 10% risk of HT3+, respectively. Mean dose and low-dose radiation parameters (V5, V10, V15, V20) of whole bone or bone cavities of LSS were correlated most significantly with HT3+., Conclusions: For predicting the risk of HT3+, whole-bone contours were superior to marrow cavity and LSS was superior to PBM by LKB modeling. The results confirm PBM and LSS as parallel organs when predicting hematologic toxicity. Recommended dose constraints to the LSS are V10 ≤80%. An LSS mean dose of 23.5 Gy is associated with a 10% risk of HT., (Copyright © 2014 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

Purpose: Hemangiomas are the most common benign tumor of infancy, affecting females more than males. Lip hemangiomas are of particular concern because of their relatively increased risk to ulcerate during the proliferative period. Ulcerated hemangiomas of the lip can lead to increased scarring, loss of lip contour, and disfigurement. Most will require surgical correction to restore normal labial anatomy., Methods: A retrospective chart review between 2004 and 2010 for surgically treated lip hemangiomas was performed. Demographic data, location of the hemangioma, age at operation, and number of operations were recorded. Two independent observers evaluated lip appearance post-operatively using 5-point scales to examine scar, symmetry, contour, and color, with 5 being excellent and 1 being poor., Results: Between 2004 and 2010, eleven patients underwent surgical correction. Ten of the eleven were female. 18% (2/11) were ulcerated. One third (4/11) was in the upper lip and two-thirds (7/11) were in the lower lip. The mean age of the patients at the time of operation was 3.6 years (range, 14 months to 17 years). The average number of operations per patient was 1.6 (range, 1-3). The average scores for lip appearance after surgical correction ranged between 3.95 (good) for lip contour to 4.5 (good to excellent) for color., Conclusions: Lip hemangiomas often require surgical correction. Treatment goals include restoration of normal lip contour and strategic placement of the incision. By taking advantage of the natural involution that occurs and careful planning, procedures can be staged to minimize distortion of the lip. Even lip hemangiomas that cross the vermilio-cutaneous (VC) junction can be excised and lip contour achieved without the need to extend scars beyond the VC junction., (Copyright © 2011. Published by Elsevier Ltd.)

Silicone has long been considered inert, but there is growing evidence that it causes an immunologic response. The use of injectable liquid silicone for cosmetic purposes is currently illegal and is associated with significant morbidity. Silicone embolism syndrome is a described phenomenon in the pulmonary literature, but it is important that it be equally recognised within the plastic surgery community., (Copyright (c) 2009 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: The vacuum-assisted closure device (VAC) has revolutionised wound care, although molecular mechanisms are not well understood. We hypothesise that the VAC device induces production of pro-angiogenic factors and promotes formation of granulation tissue and healing., Methods: A novel rodent model of VAC wound healing was established. Excisional wounds were created on rat dorsa. Wounds were dressed with Tegaderm (control group), VAC Granulofoam and Tegaderm (special control group), or VAC Granulofoam, T.R.A.C. PAD((R)) with 125 mm Hg continuous negative pressure (VAC group). Wound closure rates were calculated as a percentage of initial wound sizes. Rats were sacrificed on postoperative days 3, 5 and 7; harvested tissues were processed for histology [haematoxylin & eosin (H&E), Masson's trichrome, picrosirius red] and Western blot analysis (CD31, vascular endothelial growth factor, basic fibroblast growth factor)., Results: Statistically significant wound closure rates were achieved in the experimental group at all measured time points: day 3, 28.1% (VAC) vs 8.2% (control) and 8.8% (special control) (ANOVA, P<0.0001); day 5, 45.3% (VAC) vs 23.7% (control) and 22.5% (special control) (ANOVA, P=0.0003); day 7, 54.4% (VAC) vs 43.0% (control) and 31.5% (special control) (ANOVA; P<0.0001). Morphological evaluation by Masson's trichrome stain showed increased collagen organisation and wound maturation in the VAC group. These wounds also showed increased expression of vascular endothelial growth factor and fibroblast growth factor-2 on day 5 by Western blot analysis., Conclusion: A small animal VAC wound model was established. Wounds treated with a VAC device showed accelerated wound closure rates, increased pro-angiogenic growth factor production and improved collagen deposition. Further application of this model may elucidate other mechanisms.

Background: Prophylactic treatment for severe hemophilia A is likely to be more effective than treatment when bleeding occurs, however, prophylaxis is costly. We studied an inception cohort of 25 boys using a tailored prophylaxis approach to see if clotting factor use could be reduced with acceptable outcomes., Methods: Ten Canadian centers enrolled subjects in this 5-year study. Children were followed every 3 months at a comprehensive care hemophilia clinic. They were initially treated with once-weekly clotting factor; the frequency was escalated in a stepwise fashion if unacceptable bleeding occurred. Bleeding frequency, target joint development, physiotherapy and radiographic outcomes, as well as resource utilization, were determined prospectively., Results: The median follow-up time was 4.1 years (total 96.9 person-years). The median time to escalate to twice-weekly therapy was 3.42 years (lower 95% confidence limit 2.05 years). Nine subjects developed target joints at a rate of 0.09 per person-year. There was an average of 1.2 joint bleeds per person-year. The cohort consumed on average 3656 IU kg(-1)year(-1) of factor (F) VIII. Ten subjects required central venous catheters (three while on study); no complications of these devices were seen. One subject developed a transient FVIII inhibitor. End-of-study joint examination scores--both clinically and radiographically--were normal or near-normal., Conclusions: Most boys with severe hemophilia A will probably have little bleeding and good joint function with tailored prophylaxis, while infusing less FVIII than usually required for traditional prophylaxis.

Infantile hemangioma is an endothelial tumor that grows rapidly after birth but slowly regresses during early childhood. Initial proliferation of hemangioma is characterized by clonal expansion of endothelial cells (ECs) and neovascularization. Here, we demonstrated mRNA encoding CD133-2, an important marker for endothelial progenitor cells (EPCs), predominantly in proliferating but not involuting or involuted hemangioma. Progenitor cells coexpressing CD133 and CD34 were detected by flow cytometry in 11 of 12 proliferating hemangioma specimens from children 3 to 24 months of age. Furthermore, in 4 proliferating hemangiomas, we showed that 0.14% to 1.6% of CD45(-) nucleated cells were EPCs that coexpressed CD133 and the EC marker KDR. This finding is consistent with the presence of KDR(+) immature ECs in proliferating hemangioma. Our results suggest that EPCs contribute to the early growth of hemangioma. To our knowledge, this is the first study to show direct evidence of EPCs in a human vascular tumor.

Background: High level resistance to carbapenem antibiotics in gram negative bacteria such as Bacteroides fragilis is caused, in part, by expression of a wide-spectrum metallo-beta-lactamase that hydrolyzes the drug to an inactive form. Co-administration of metallo-beta-lactamase inhibitors to resistant bacteria is expected to restore the antibacterial activity of carbapenems., Results: Biphenyl tetrazoles (BPTs) are a structural class of potent competitive inhibitors of metallo-beta-lactamase identified through screening and predicted using molecular modeling of the enzyme structure. The X-ray crystal structure of the enzyme bound to the BPT L-159,061 shows that the tetrazole moiety of the inhibitor interacts directly with one of the two zinc atoms in the active site, replacing a metal-bound water molecule. Inhibition of metallo-beta-lactamase by BPTs in vitro correlates well with antibiotic sensitization of resistant B. fragilis., Conclusions: BPT inhibitors can sensitize a resistant B. fragilis clinical isolate expressing metallo-beta-lactamase to the antibiotics imipenem or penicillin G but not to rifampicin.

High level methicillin resistance in Staphylococcus aureus is dependent upon the acquisition of the mecA gene encoding penicillin-binding protein 2a (PBP2a). PBP2a is a member of a family of peptidoglycan biosynthetic enzymes involved in assembly of the cell wall in bacteria and is poorly inactivated by beta-lactam antibiotics. We describe a 96-well-filter binding assay using recombinant, soluble PBP2a which allows for kinetic measurement of penicillin binding. The deacylation rate constant for the PBP2a-penicillin G covalent complex was found to be 5.7 +/- 1.0 x 10(-5) s-1 at 30 degrees C (half-life of approximately 200 min). For the PBP2a acylation reaction, the value of K(m) (penicillin G) = 0.5 +/- 0.1 mM and kcat = 1 x 10(-3) s-1, which yields a second-order rate constant (kcat/K(m)) for inactivation of 2.0 M-1 s-1. Using this assay, several non-beta-lactam inhibitors including Cibacron blue have been found which exhibit IC50 values between 10 and 30 microM. The binding affinities of several carbapenems and beta-lactams correlated well between the filter binding assay described in this report and an electrophoretic assay for PBP2a using membranes prepared form methicillin-resistant S. aureus.

Gangliogliomas are rare tumors of the central nervous system that account for approximately 1% of all brain tumors. Histologically, gangliogliomas are composed of intimately admixed glial and neuronal components, the pathological origins of which remain to be characterized. Clonal analysis through examination of the pattern of the X chromosome inactivation allows one to distinguish monoclonal differentiation of a genetically abnormal progenitor cell from parallel, but independent, clonal expansion of two different cell types during tumorigenesis in biphasic neoplasms, such as gangliogliomas. In the present study, we investigated the clonality of eight gangliogliomas from female patients using both methylation- and transcription-based clonality assays at the androgen receptor locus (HUMARA) on the X chromosome. Among tumors from seven patients who were heterozygous at the HUMARA locus, five were identified as monoclonal with the methylation-based clonality assay, and the results were confirmed by the transcription-based method, whereas two were shown to be polyclonal by the methylation-based clonality assay but monoclonal by transcription-based clonality analysis. We conclude that the predominant cell types in most gangliogliomas are monoclonal in origin and derive from a common precursor cell that subsequently differentiates to form neoplastic glial and neuronal elements.

The lysis of susceptible targets by efficient cytotoxic T lymphocytes (CTL) increases both with time and with the ratio of CTL to target. Simple methods for calculating a killing rate constant from the time dependence of killing and for calculating the relation of the killing rate constant to the concentration of exocytosable granzyme A are given. Application of these methods to the killing of target cells by the highly efficient mouse CTL AR1 is presented. AR1 needed granzyme A for efficient killing. AR1 contained sufficient exocytosable granzyme A to kill at about 80% of the rate possible at infinite exocytosable granzyme A.

The adaptation of an analytical procedure for aggrecan based upon gel-permeation chromatography to an FPLC-based protocol has significantly sped up the analysis. The faster assay has permitted determination of the kinetic constants for digestion of human aggrecan by human stromelysin-1. Monomeric aggrecan appeared to be hydrolyzed by stromelysin-1 to multiple forms with lower molecular weight. The disappearance of high-molecular-weight aggrecan was first-order, showing Km much larger than 2 microM and kc/Km = 4000 M-1 s-1 at pH 7.5. The disappearance of high-molecular-weight aggrecan upon hydrolysis by stromelysin-1 at pH 5.5 was also first-order, with kc/Km = 10,700 M-1 s-1. The disappearance of high-molecular-weight aggrecan at pH 7.5 was first-order for digestion by human leukocyte elastase with kc/Km = 230,000 M-1 s-1, by human cathepsin G with kc/Km = 4200 M-1 S-1, and by human plasma plasmin with kc/Km = 2800 M-1 s-1, all with Km much larger than 2 microM.

The synthetic antiprotease, FUT-175 (6-amidino-2-naphthyl-4-guanidinobenzoate), was found to be an extraordinarily potent and rapid inhibitor of human Q31 cytotoxic T-lymphocyte granzyme A. The granzyme A was inhibited in a time-dependent manner with kobs/i = 430,000 +/- 80,000 M-1 s-1. Four other FUT-175 analogs were also found to be potent, rapid Q31 granzyme A inhibitors. All five compounds inhibited Q31 cytotoxic T-lymphocyte-mediated cytolysis of human JY lymphoma cells, but at concentrations far in excess of those needed for granzyme A inhibition. The data presented suggest that postmarketing surveillance of FUT-175 should include a review of possible immunosuppressive side-effects, such as increased susceptibility to viral infections and to neoplastic transformations.

A synthetic tetradecapeptide, H-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Val-Ile-His-Ser-OH, which corresponds to the 13 amino terminal residues of human angiotensinogen plus a carboxy terminal serine to replace a suggested site of carbohydrate attachment, has been shown to be a good substrate for human kidney renin. At pH 7.2 and 37 degrees C the KM or Michaelis constant was 8.4 +/- 2.9 microM, and the VM or velocity at infinite tetradecapeptide concentration was 11.3 +/- 2.4 mumol angiotensin I made per hour per milligram renin. The tetradecapeptide was highly resistant to cleavage by mouse submaxillary renin. The tetradecapeptide was also slowly cleaved by human liver cathepsin D, by rabbit lung angiotensin-converting enzyme, and by reconstituted human serum, but did not yield angiotensin I. Thus, this synthetic renin substrate should permit more specific measurement of human kidney renin activity.