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Purpose: Recently, the importance of molecular diagnosis has increased, along with the volume of specimens required for diagnosis. Biopsy procedures must simultaneously reduce invasiveness and ensure the collection of adequate tissue volume. We examined the efficacy and safety of endoscopic biopsy using a minimal diameter cylinder.Methods: Patients who underwent endoscopic biopsy surgery with a 6-mm diameter cylinder for intraparenchymal lesions were included. Postoperative hematoma formation and the extent of trajectory scarring were assessed. Molecular genetic analysis was performed for cases of diffuse infiltrated glioma.Results: Fifty-two procedures performed on 51 patients were analyzed in this study. Postoperative neurological deterioration was not observed in any case. A pathological diagnosis was made for all patients. Postoperative CT revealed no hematoma after 49 procedures and a small hematoma after 3 procedures, and no patients required additional treatment. A postoperative trajectory scar less than 5 mm in size was observed after 30 procedures, a scar of 5-10 mm was observed after 19 procedures, and a scar larger than 10 mm was observed after 3 procedures at 1 week after surgery, and 40, 6 and 0 scars were observed at 3 months after surgery. Molecular genetic analysis was performed in 17 cases, resulting in a change to a higher grade in the integrated diagnosis of 3 cases.Conclusions: Endoscopic biopsy using a small-diameter cylinder is a possible alternative biopsy technique for intraparenchymal lesions. This surgical technique is useful especially in cases where hemorrhagic complications are expected.Trial registrationRegistry name and number: Efficacy and safety of the neuro-endoscopic treatment for brain tumors. (2019-0254)

Cerebral cavernous malformations (CMs) presenting with focal neurological symptoms or mass effects require surgical removal. In recent years, cylindrical retractors have been widely utilized for the removal of deep-seated lesions during both microscopic and endoscopic surgery. In the present study, we evaluated the efficacy and safety of endoscopic transcylinder removal of CMs using a novel wet-field technique.We included 13 patients with supratentorial CMs who had undergone endoscopic transcylinder surgery between April 2013 and March 2022. One patient experienced recurrence of the CM and underwent a second endoscopic transcylinder surgery. Therefore, we retrospectively evaluated 14 procedures. The surgical field was continuously irrigated with artificial cerebrospinal fluid to maintain expansion and visualization of the tumor bed. We termed this method as the "wet-field technique." Patient characteristics, symptoms, and pre- and postoperative magnetic resonance imaging results were obtained from medical records.The average maximum CM diameter was 35.3 mm (range: 10-65 mm). Cylinder diameters were 6 mm in eight procedures, 10 mm in four procedures, and 17 mm in one procedure. Wet-field technique was applied in all cases. The endoscope provided a bright field of view even under water. Continuous water irrigation made it easier to observe the entire tumor bed which naturally expanded by water pressure. Gross total resection was achieved in 13 procedures, while subtotal resection was achieved in one procedure. No surgical complications were observed.The endoscopic transcylinder removal using wet-field technique is safe and effective for the removal of symptomatic intracranial supratentorial CMs.

Extended endonasal transsphenoidal surgery (eTSS) offers a wide surgical field for various parasellar lesions; however, intraoperative high-flow cerebrospinal fluid (CSF) leakage is inevitable. Therefore, secure sellar reconstruction methods are essential to prevent postoperative CSF leakage. Although collagen matrix has been applied for dural reconstruction in neurosurgery, its suitability for application in extended eTSS remains unclear.Fifteen patients underwent modified shoelace dural closure using collagen matrix after lesionectomy via extended eTSS. In this technique, a collagen matrix, which was placed subdurally (inlay graft), was continuously sutured with both open dural edges like a shoelace. Then, another collagen matrix was placed epidurally (onlay graft), and rigid reconstruction was performed using the septal bone and a resorbable fixation mesh. Postoperative CSF leakage did not occur in fourteen patients, but did in one patient with tuberculum sellae meningioma. In this case, the CSF leakage point was detected just around the area between the coagulated dura and the adjacent collagen matrix. The collagen matrix harvested from this area was pathologically examined; neovascularization and fibroblastic infiltration into the collagen matrix were not detected. On the other hand, neovascularization and fibroblast infiltration into the collagen matrix were apparent on the surface of the collagen matrix harvested from the non-CSF leakage area.Our novel dural closure technique using collagen matrix could be an effective option for sellar reconstruction in extended eTSS; however, it should be applied in patients in whom normal dural edges are preserved.Clinical trial registrationNot applicable

Purpose Postoperative pituitary dysfunction, a critical problem in the treatment of craniopharyngiomas, can occur even when the pituitary stalk is preserved. We hypothesized that vascular compromise of the primary superior hypophyseal artery (pSHA) may be related to this occurrence. Methods We performed a retrospective review of 131 patients with craniopharyngioma who underwent endoscopic transsphenoidal surgery from April 2009 to September 2021. Initial surgery, preoperative normal pituitary function or pituitary dysfunction in one axis, and morphological preservation of the pituitary stalk were included. Data on the age, sex, maximum tumor diameter, Kassam type and tumor resection rate of the included patients were obtained from their medical records. The branches of the pSHA are divided mainly into chiasmatic branches (Cb), infundibular branches (Ib), and descending branches (Db). We analyzed the association between postoperative pituitary function and preservation of these branches. Results Twenty of the 131 patients met the criteria. The preoperative anterior pituitary functions were normal in 18 patients, and there was isolated growth hormone deficiency in two patients. No patient had preoperative diabetes insipidus (DI). The postoperative anterior pituitary function was unchanged in eight patients. Permanent DI did not occur in 15 patients. Bilateral preservation of the pSHA Ib was the only associated factor for maintaining anterior pituitary function. In contrast, the preservation of any pSHA branch yielded no significant difference in postoperative permanent DI. Conclusions In craniopharyngioma surgery, bilateral preservation of the pSHA Ib provides favorable postoperative anterior pituitary function; however, such preservation may have little effect on postoperative DI occurrence.

We explored chromatographic conditions to obtain high resolution in protein separations by ion-exchange chromatography (IEC) on a macroporous anion-exchange resin of 10 microm in particle diameter. We studied effects of flow-rate, gradient time (steepness of salt concentration gradient) and column length on resolution in wide ranges. It was found that very high resolutions are attainable at long gradient times with long columns. The resolution continuously became higher as the gradient time and the column length became longer except in some special cases. The dependence of resolution on gradient time was particularly great when the column was long and the gradient time for the change of 0-0.5 M NaCl was longer than 2 h. On the other hand, the effect of flow-rate on resolution was very small. Although the separations at long gradient times with long columns have not been popular in high-performance IEC and it takes several hours for one separation, such separations should be advantageous when very high resolutions are required like in proteomics research.

We investigated hydrophobicity gradient columns composed of two columns packed with supports of different hydrophobicities in order to save time in protein separation by hydrophobic interaction chromatography at low salt concentration using a crude sample of trypsin inhibitor as a model sample. One of the two hydrophobicity gradient columns was packed with a support whose hydrophobicity was critically controlled for target protein (trypsin inhibitor) and the other was packed with a support which was less hydrophobic than the critically controlled hydrophobicity support. It was found that the hydrophobicity gradient columns are useful to separate samples containing impurities of a wide range of hydrophobicities within a reasonable time.

We investigated protein separation by hydrophobic interaction chromatography (HIC) at low salt concentration on the supports of various hydrophobicities. Hydrophobic proteins could be successfully separated with more than 90% recovery by gradient elution of ammonium sulfate from 0.3-0.5 M to 0 in 50 mM phosphate buffer (pH 6.8) by using supports whose hydrophobicities were properly adjusted individually for each protein. Satisfactory results were also obtained by isocratic elution without ammonium sulfate and gradient elution of ethanol from 0 to 10%. HIC at low salt concentration was compatible with other modes of liquid chromatography like ion-exchange chromatography. On the other hand, it was not successful to separate hydrophilic proteins at low salt concentration. Recoveries of hydrophilic proteins decreased before they were retained enough as support hydrophobicity increased. Therefore, it is inevitable to use a higher concentration of salt, e.g., 1-2 M ammonium sulfate, on hydrophilic or moderately hydrophobic support in order to retain hydrophilic proteins without decrease in recovery.

In this paper, we develop a model of two-sided matching markets with externalities. A new concept of stability of matchings is proposed and it is shown to be the unique one that ensures the general existence. Moreover, it is demonstrated that our stability does not contradict Pareto optimality. Some extensions of the model are also discussed.Journal of Economic LiteratureClassification Numbers: C71, C78, D62.

This paper presents axiomatic characterizations of the core of assignment problems. In the main axiomatization theorem we use six axioms including the consistency (CONS) and the weak pairwise-monotonicity (W.P.MON) which are firstly proposed and defined for this setup in the present paper. Since an assignment problem may be converted into a model of a private ownership economy with indivisible goods and the core of the assignment problem coincides with the set of the competitive allocations of the economy, our characterization theorems also give axiomatic characterizations of the set of competitive allocations. Because the consistency is a desirable property of resource allocation mechanisms, our main result gives a new normative implication of competitive equilibria.

A characterization theorem of the core of two-sided matching problems is proved. The theorem characterizes the core by means of four axioms, the Pareto optimality, consistency, converse consistency, and anonymity. It is shown that all of them are logically independent.

We evaluated hydrophobic interaction chromatography (HIC) at low salt concentration for the capture of proteins from feed stocks by using monoclonal antibodies as model samples. It was indicated that the HIC at low salt concentration on critical hydrophobicity supports has a potential for capturing hydrophobic monoclonal antibodies directly from large volumes of feed stocks and recovering bound monoclonal antibodies in high yield. On the other hand, the HIC at low salt concentration did not seem so useful for the capture of weakly hydrophobic monoclonal antibodies. The recovery of weakly hydrophobic monoclonal antibodies from columns packed with critical hydrophobicity supports was not quantitative and significantly decreased as the residence time of the monoclonal antibodies in the columns became longer.

An affinity sorbent, hydrophilic polymer-based carrier of different pore size (Toyopearl) with immobilized p-aminobenzamidine (ABA), has been prepared. Its basic properties and some applications for protein purification were studied. ABA, which is a synthetic inhibitor for trypsin-like proteases, was covalently immobilized to Toyopearl by reductive amination. The ligand density and binding capacity for porcine trypsin varied depending on the pore size of Toyopearl. The maximum binding capacity of the immobilized p-aminobenzamidine Toyopearl (ABA-Toyopearl) for trypsin was more than 40 mg/ml gel. ABA-Toyopearl thus obtained was very stable below pH 8 and was successfully used for high-performance affinity chromatography of trypsin-like proteases such as trypsin, thrombin, tissue-type plasminogen activator or urokinase in a single step at 25 degrees C.

We explored chromatographic conditions to obtain high resolution in protein separations by ion-exchange chromatography (IEC) on a nonporous anion-exchange resin of 2.5 μm in particle diameter. We studied the effects of gradient time (steepness of salt concentration gradient), flow-rate and column length on resolution in much wider ranges than had been studied before. It was found that two distinct conditions exist that provide high resolution. The first is a condition which has widely been employed in current high-performance IEC, namely, a combination of short gradient time, high flow-rate and comparatively short column. Separation times are usually 5–30 min, and even more rapid (1–2 min) separations are possible. The second is the condition which has rarely been employed in high-performance IEC. It is a combination of long gradient time, low flow-rate and long column. Although it takes several hours for one separation, very high resolution is attainable.

The basic properties of a new dye affinity adsorbent Toyopearl AF-Blue HC-650M and its applications to the purification of proteins were studied. The binding capacity for human serum albumin (HSA) was greater than 18 mg per ml gel. The dye leakage from Toyopearl AF-Blue HC-650M in 0.5 M NaOH and 0.5 M HCI was less compared with an agarose adsorbent. Caustic stability study also demonstrated this material withstood exposure to 0.1 M NaOH for 1 month with no significant loss of binding capacity for HSA. We purified human albumin from human serum and lactate dehydrogenase (LDH) from rabbit muscle extract in a single step. Sodium dodecylsulfate-polyacrylamide gel electrophoresis indicates that human albumin and LDH were highly purified.

High-speed gel-permeation chromatography (GPC) of water-soluble polymers has been investigated by using TSK-GEL, type-PW columns packed with small porous particles. Being semirigid, the column packing could be operated under high pressure and, therefore, it was possible to achieve high-speed GPC. A resolution higher than that of ordinary GPC in organic solvent system was attained when the measurement of one sample was completed within 40 min with a 6-ft column set. Samples with a wide range of molecular weights, from oligomers to polymers having a molecular weight greater than 106, could be fractionated. Dextran, polyethylene glycol, polyacrylamide, poly(vinyl alcohol), and poly(vinyl pyrrolidone) were separated according to molecular size with no evidence of adsorption. Investigation of other water soluble polymers is now in progress.

A packing material for size-exclusion chromatography, Toyopearl, which was derivatized by introducing amino groups, was found to be a good support for the immobilization of urease. The immobilized enzyme had an optimum pH of 7, the same value as for intact urease. In the use of the enzyme, packed in PTFE tubing (ca. 8 cm × 0.7 mm I.D.) in a flow system, the addition of ethylenediaminetetraacetic acid (EDTA) to the eluent was found to be essential. With phosphate buffers containing EDTA, a constant high value of the enzyme activity could be obtained for 21 days at 37°C.

The purification of enzymes was investigated by high-speed gel filtration on TSK-GEL G3000SWG columns packed with porous silica gel deactivated by chemically bonded hydrophilic compounds. Crude β-galactosidase from bacterial cells and commercial urease were purified ca. 15-fold in a single gel filtration. These enzymes were eluted within an hour from the column and the recoveries of enzymatic activity were almost 100% although the operation was carried out at room temperature (22°). Samples up to 100 mg could be applied to the column without loss of separation efficiency.

Separation ranges for gel filtration on TSK-GEL SW columns, G2000SW, G3000SW and G4000SW, were measured for globular protein, dextran and polyethylene glycol. It was possible to separate globular proteins of molecular weights from 5000 to 7,000,000, dextrans of molecular weights from 1000 to 500,000 and polyethylene glycols of molecular weights from 500 to 250,000 by using these three columns of different pore sizes. The column having the highest separation efficiency for globular proteins was also determined. The highest separation efficiency for molecular weights of less than 30,000, 30,000–500,000 and greater than 500,000 was exhibited by G2000SW, G3000SW and G4000SW, respectively.

The N—A isomerization (the intramolecular SH/S—S exchange reaction) of bovine mercaptalbumin (BMA) in alkaline medium was studied by using ion-exchange high-performance liquid chromatography (HPLC) and moving-boundary electrophoresis. Results obtained by ion-exchange HPLC on the N-A isomerization of BMA were consistent with those by moving-boundary electrophoresis and showed at least two kinds of the A-form, A1 and A2, indicating that the N—A isomerization is a multi-step reaction. The rate of the N—A isomerization was strongly suppressed in [2H]water solution. The suppresion by [2H]water might support the current view that intra- and intermolecular hydrophobic and/or hydrogen bonds are strengthened in [2H]water.

High-speed gel filtration of proteins was performed in sodium dodecyl sulphate aqueous solutions on TSK-GEL SW type columns. The separation ranges of G2000SW, G3000SW and G4000SW were, respectively, 15,000–25,000, 10,000–100,000 and 15,000–300,000. G3000SW showed the highest separation efficiency in the molecular weight range below ca. 60,000, while G4000SW showed the highest separation efficiency above molecular weight of ca. 60,000. The elution behaviour of proteins was greatly affected by sodium phosphate concentration in the eluent and the optimum sodium phosphate concentration was 0.05–0.2 M.

Detection of residual antibiotics, such as penicillin (PC), streptomycin (SM), and oxytetracyclin (OTC) in slaughtered swine carcases was made by the standard bioassay technique, using Sarcina lutea ATCC 9341, Bacillus subtilis ATCC 6633, and Bacillus cereus var. mycoides ATCC 11778, respectively.Specimens obtained for the examination were neck muscle, liver and kidney of 29 pigs which had been treated with the above mentioned antibiotics. In addition to this field survey, an experimental study on the reliability of disk method, for the detection of penicillin incorporated in pork extract, was also carried out comparing with the standard cup method.As the results it was found that 1 (3.7%) out of 27 muscles, 6 (29.0%) of 21 livers, and 4 (20.0%) kidney contained 0.16-1.1IU/g of PC, while 3 of 21 (14.2%) liver and 2 of 21 (9.5%) kidney contained 0.15-0.75μg/g of SM. However, none of the specimen tested contained any detectable amount of OTC.As for the reliability of the disk method, it was found that almost the same sensitivity with that of the cup method could be achieved, especially at a lower concentration of the antibiotics. Therefore, it is recommeded to use disk method as a routine screenig procedure for the detection of residual penicillin in animal tissues.

Butyl-Toyopearl 650, a butyl derivative of Toyopearl HW-65, was synthesized for use in hydrophobic chromatography. Water-soluble enzyme proteins were adsorbed on butyl-Toyopearl 650 in the presence of ammonium sulfate and eluted easily in the absence of the salt. Cytochrome c, myoglobin, and chymotrypsinogen A were successfully separated on a butyl-Toyopearl 650 column in order of their individual hydrophobicity by decreasing the concentration of ammonium sulfate contained in the buffer eluant. Based on these results, the use of butyl-Toyopearl 650 is demonstrated for the hydrophobic separation of water-soluble enzyme proteins.