Glycosylation of lactosylceramide analogs in animal cells: amphipathic disaccharide primers for glycosphingolipid synthesis

N-Acylaminoethyl lactosides as lactosylceramide analogs as well as n-alkyl lactosides were examined for their ability to prime glycosphingolipid (GSL) synthesis in mouse melanoma B16 cells. Using compounds radiolabeled in a galactose residue and having nondegradable thioglucosidic linkages in lactoside, direct glycosylation was shown to occur at the terminal galactose residue of lactosides subsequent to uptake by cells and dissemination into Golgi compartments. B16 cells took in lactosides temperature-dependently to the point of saturation. All lactosides were taken up and glycosylated by B16 cells. C8-lactosides could not settle on the plasma membrane, while C16-lactosides remained within the cells. Glycosylation in all cases was cellular GSL-specific, suggesting the involvement of glycosyltransferases in GSL synthesis during glycosylation of lactosides. The priming of GSL synthesis by lactosides inhibited the cell surface expression of endogenous GM3 in B16 cells. Lactosylceramide analogs are thus shown useful as primers for glycosylation and to modify GSL expression, and these features should facilitate clarification of the functions of GSLs which have yet to be elucidated.

Difference of hyaluronidase produced by human tumor cell lines with hyaluronidase present in human serum as revealed by zymography

Human carcinoma cells cultured in serum free medium produced an enzyme present as two different isoforms of 62 and 59 kDa which was found to degrade hyaluronan and chondroitin sulfate, with optimum activity at pH 4.0 and 0.03 M NaCl. The activity was suppressed by treatment with 250 mM apigenin and 1 mM DTT. The one-dimensional and two-dimensional gel patterns of tumor hyaluronidase differed from those of human serum hyaluronidase. Deglycosylation of tumor hyaluronidase caused nearly complete elimination of activity, suggesting the importance of sugar chains in enzymatic function. The results of treatment with neuraminidase, in addition to the findings for the enzyme mentioned above, suggest hyaluronidase from carcinoma cells and serum hyaluronidase to differ in sugar chains and/or the core protein. Tumor hyaluronidase was shown to be endo-beta-N-acetyl-D-hexosaminidase and tetrasaccharide was identified as the major product, thus indicating the tumor hyaluronidase to be a testis-type hyaluronidase.

Effects of volume loading on pulmonary venous flow and its relation to left atrial functions

Although pulmonary venous (PV) flow is closely related to left atrial (LA) pressure dynamics, few investigators have discussed it in relation to LA functions, i.e., reservoir, conduit, and booster pump functions. We examined changes in PV flow rate, LA dimension, and left ventricular filling volume in 11 dogs, and assessed the effects of multistaged volume loading on PV flow and LA functions. Systolic PV flow rate (S) increased significantly and reached a plateau, reflecting a limited LA reservoir function. Diastolic PV flow rate (D) increased significantly with an increase in LA pressure. S/D ratio increased non-significantly from 0.87 +/- 0.07 before volume loading to 0.96 +/- 0.08 until S reached a plateau and then decreased to 0.76 +/- 0.08 (p < 0.05) because of a significant increase in D without an increase in S at the higher stages of volume loading. During atrial contraction, increases in LA active shortening and left ventricular filling volume were limited, indicating a limited LA forward ejection. The difference between PV flow rate just before and at the end of atrial contraction increased and correlated positively with left ventricular end-diastolic pressure (r = 0.57, p < 0.01). PV flow varies according to the degree of volume loading and reflects LA functions, which exhibit limited increases in response to volume loading.

Positive correlation between inhibitors of matrix metalloproteinase 1 and matrix metalloproteinases in malignant ovarian tumor tissues

To investigate the relation between matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in malignant ovarian tumor, MMP and TIMP activities in conditioned media of 16 malignant ovarian tumor tissues and six normal ovaries were detected by zymography and reverse zymography, respectively and were quantitated with a densitometer. TIMP-1 and TIMP-2 were detected in all normal and malignant ovarian tumor tissues by reverse zymography. In normal ovaries, the intensity of TIMP-2 bands was stronger than TIMP-1, but in malignant tumor tissues those of TIMP-1 were stronger. The ratios of TIMP-1 to TIMP-2 and MMP-9 to MMP-2 were significantly higher in malignant tumor tissues than in normal ovaries (P < 0.001). TIMP activity consisting of TIMP-1 and TIMP-2 correlated significantly to MMP activity of MMP-2 and MMP-9 (r = 0.67, P < 0.005). There was a significant correlation between TIMP-1 activity and MMP activity (r = 0.72, P < 0.001), but no correlation was observed between TIMP-2 activity and MMP activity. The high level of TIMP-1 appeared to be related to malignant phenotype in ovaries as well as the high level of MMP-9.

Effects of C-type natriuretic peptide on renal vasoconstriction in dogs

Intrarenal arterial infusion of C-type natriuretic peptide (CNP, 50 ng/kg per min) increased urine flow rate without affecting glomerular filtration rate. Intrarenal arterial bolus injection of angiotensin II (25, 50 and 100 ng) or of norepinephrine (0.25, 0.5 and 1.0 microg) reduced renal blood flow. The blood flow response induced by angiotensin II was slightly attenuated but the response induced by norepinephrine was unaffected during CNP infusion. These results suggest that exogenous CNP, even at the pharmacological dose that can induce diuresis, has little effect on the canine renal vasculature.

Bradykinin induced dilatation of human epicardial and resistance coronary arteries in vivo: effect of inhibition of nitric oxide synthesis

OBJECTIVE

To clarify whether endothelium derived nitric oxide contributes to exogenous bradykinin induced dilatation of human epicardial and resistance coronary arteries in vivo.

DESIGN

Quantitative coronary angiography and Doppler flow velocity measurements were used to determine the effects of the nitric oxide synthesis inhibitor, NG-monomethyl-L-arginine (L-NMMA), on bradykinin induced dilatation of the epicardial and resistance coronary arteries.

SETTING

Hiroshima University Hospital.

PATIENTS

20 patients (16 men and four women, mean (SD) age 56 (9) years) with angiographically normal smooth epicardial coronary arteries.

INTERVENTIONS

Serial infusions of bradykinin (0.5, 1.5, and 2.5 micrograms/min) were given into the left coronary ostium before and after L-NMMA infusion (60 mumol/min).

MAIN OUTCOME MEASURES

Epicardial coronary diameter, coronary blood flow, and coronary vascular resistance.

RESULTS

Bradykinin-induced epicardial coronary vasodilatation after L-NMMA (dilatation by 2.5 micrograms/min, 3.8(1.4)% in the proximal and 5.9(1.8)% in the distal segments, mean (SEM)) was less (p < 0.001, respectively) than before L-NMMA (11.7(2.5)% and 15.1(2.0)%, respectively). In contrast, L-NMMA did not affect the bradykinin induced increase in coronary blood flow and decrease in coronary vascular resistance.

CONCLUSIONS

Endothelium derived nitric oxide contributes to bradykinin induced dilatation of epicardial coronary arteries, but may be less important in coronary resistance vasodilatation.

Genome organization of human 48-kDa oligosaccharyltransferase (DDOST)

The enzyme oligosaccharyltransferase (dolichyl-diphosphooligosaccharide-protein glycosyltransferase; EC 2. 4.1.119) (DDOST) catalyzes the transfer of a high-mannose oligosaccharide (GlcNac2Man9Glc3) from a dolichol-linked oligosaccharide donor (dolichol-P-GlcNac2Man9Glc3) onto the asparagine acceptor site within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains across the membrane of the endoplasmic reticulum. We isolated mouse and human DDOST cDNAs from retinoic acid-treated mouse P19 EC cells and human NT-2 cells, respectively. DDOST mRNA is expressed intensely in heart and pancreas, but at lower levels in brain. Here we show that the human DDOST 48-kDa subunit gene (HGMW-approved symbol DDOST) is organized into 11 exons expanding about 9 kb. This DDOST subunit gene is localized on chromosome 1p36.1 by fluorescence in situ hybridization analysis.

Blink induced centrotemporal spikes in benign childhood epilepsy with centrotemporal spikes

A 10 year old girl with benign childhood epilepsy with centrotemporal spikes showed centrotemporal spikes induced by blinking even in a dark room. Spikes could not be induced by photic stimulation, eye closure, eye movement, eye deviation, or passive blinks. There have been no previous reports of spikes induced by blinks in benign childhood epilepsy with centrotemporal spikes.

Coronary segmental responses to acetylcholine and bradykinin in patients with atherosclerotic risk factors

This study was designed to elucidate the nature of coronary endothelial dysfunction in patients with hypertension and/or hypercholesterolemia and normal smooth coronary arteries by evaluating the coronary vascular responses to acetylcholine and bradykinin. The study included 19 patients (10 men; age [mean +/- SD] 61 +/- 9 years) with angiographically normal smooth coronary arteries and either hypertension (n = 7) and/or hypercholesterolemia (n = 13). Patients received acetylcholine (3 or 30 microg/min) infusions followed by bradykinin (0.5, 1.5, 2.5 microg/min) and nitroglycerin (200 microg/min) infusions into the left coronary ostium. Epicardial coronary artery diameters were measured by quantitative angiography. Angiography detected both vasoconstricted and dilated segments following acetylcholine infusion. Bradykinin significantly dilated both types of segments (p <0.001, respectively). However, bradykinin-induced dilation was significantly greater in segments exhibiting acetylcholine-induced vasodilation than in those exhibiting vasoconstriction (p <0.01 in the proximal portion and p <0.02 in the distal portion). Nitroglycerin-induced dilation was similar in all segments. These results suggest that coronary endothelial dysfunction may be a heterogeneous process in patients with coronary risk factors. Moreover, the mechanism underlying diminished endothelium-dependent dilation involves not only the muscarinic receptor, but also B2-kinin receptor.

Triple synergism of human T-lymphotropic virus type 1-encoded tax, GATA-binding protein, and AP-1 is required for constitutive expression of the interleukin-5 gene in adult T-cell leukemia cells

Accumulated evidence demonstrates that adult T-cell leukemia (ATL) is frequently associated with eosinophilia, and human T-lymphotropic virus type 1 (HTLV-1)-infected cells frequently express interleukin-5 (IL-5). However, the molecular mechanism of constitutive IL-5 expression in HTLV-1-infected cells remains unclear. To clarify the mechanism of aberrant IL-5 expression in HTLV-1-infected cells, we investigated the response of the human IL-5 promoter to the HTLV-1-encoded protein Tax. Cotransfection experiments using Jurkat cells revealed that Tax is incapable of activating the IL-5 promoter by itself but that it synergistically transactivates the promoter with GATA-binding protein (GATA-4) and 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulation. By introducing a series of mutations within the IL-5 promoter, we found that conserved lymphokine element 0 (CLE0) is responsible for mediating the signal induced by Tax-TPA. A deletion construct of the promoter indicated that the -75 GATA element and CLE0 are sufficient to mediate synergistic activation of the IL-5 promoter. Electrophoretic mobility shift assays using Jurkat cell nuclear extracts demonstrated that TPA induces a transcription factor to bind CLE0, and an experiment using JPX-9 cell nuclear extracts showed that Tax enhances this binding activity. An antibody supershift experiment revealed that this band consists of c-Jun and JunD. However, among the Jun family members, only c-Jun is able to cooperate with Tax and GATA-4 to activate the IL-5 promoter. We have determined the minimum factors required for IL-5 gene activation by reconstituting the IL-5 promoter activity in F9 cells. This is the first report to demonstrate the functional involvement of Tax protein in IL-5 gene regulation and to suggest the functional triple synergism among Tax, GATA-4, and AP-1, which disrupts regulated control of the gene and leads to constitutive expression of the IL-5 gene.

Precise switching of DNA replication timing in the GC content transition area in the human major histocompatibility complex

The human genome is composed of long-range G+C% (GC%) mosaic structures thought to be related to chromosome bands. We previously reported a boundary of megabase-sized GC% mosaic domains at the junction area between major histocompatibility complex (MHC) classes II and III, proposing it as a possible chromosome band boundary. DNA replication timing during the S phase is known to be correlated cytogenetically with chromosome band zones, and thus the band boundaries have been predicted to contain a switch point for DNA replication timing. In this study, to identify to the nucleotide sequence level the replication switch point during the S phase, we determined the precise DNA replication timing for MHC classes II and III, focusing on the junction area. To do this, we used PCR-based quantitation of nascent DNA obtained from synchronized human myeloid leukemia HL60 cells. The replication timing changed precisely in the boundary region with a 2-h difference between the two sides, supporting the prediction that this region may be a chromosome band boundary. We supposed that replication fork movement terminates (pauses) or significantly slows in the switch region, which contains dense Alu clusters; polypurine/polypyrimidine tracts; di-, tri-, or tetranucleotide repeats; and medium-reiteration-frequency sequences. Because the nascent DNA in the switch region was recovered at low efficiency, we investigated whether this region is associated with the nuclear scaffold and found three scaffold-associated regions in and around the switch region.

The phosphatidylinositol 3' kinase pathway is required for the survival signal of leukocyte tyrosine kinase

Leukocyte tyrosine kinase (LTK) is a receptor tyrosine kinase which belongs to the insulin receptor superfamily and is mainly expressed in pre-B lymphocytes and neuronal tissues. Recently, we demonstrated that LTK utilizes Shc and IRS-1 as two major substrates and while both equally activate the Ras pathway, only IRS-1 suppresses apoptosis of hematopoietic cells, suggesting the existence of another unidentified signaling pathway downstream of IRS-1, which is relevant to the anti-apoptotic activity. In the present study, we found that wortmannin, a specific inhibitor of phosphatidylinositol 3' (PI3)-kinase, abolished the survival effects of LTK. Although c-Cbl is found to be phosphorylated by LTK and therefore is a second candidate linking LTK with the PI3-kinase pathway along with IRS-1, we found that the p85 subunit of PI3 kinase directly binds to tyrosine 753 of LTK, which is located within a YXXM motif, a consensus binding amino acid sequence for the SH2 domain of p85, but fails to bind to IRS-1 or c-Cbl. Ba/F3 cells which stably express the EGF receptor-LTK chimeric receptor carrying a mutation at tyrosine 753 fell into apoptotic death even in the presence of EGF, indicating that the PI3 kinase pathway is required for the survival effects of LTK.

Purification and molecular cloning of SH2- and SH3-containing inositol polyphosphate-5-phosphatase, which is involved in the signaling pathway of granulocyte-macrophage colony-stimulating factor, erythropoietin, and Bcr-Abl

Grb2/Ash and Shc are the adapter proteins that link tyrosine-kinase receptors to Ras and make tyrosine-kinase functionally associated with receptors and Ras in fibroblasts and hematopoietic cells. Grb2/Ash and Shc have the SH3, SH2, or phosphotyrosine binding domains. These domains bind to proteins containing proline-rich regions or tyrosine-phosphorylated proteins and contribute to the association of Grb2/Ash and Shc with other signaling molecules. However, there could remain unidentified signaling molecules that physically and functionally interact with these adapter proteins and have biologically important roles in the signaling pathways. By using the GST fusion protein including the full length of Grb2/Ash, we have found that c-Cbl and an unidentified 135-kD protein (pp135) are associated with Grb2/Ash. We have also found that they become tyrosine-phosphorylated by treatment of a human leukemia cell line, UT-7, with granulocyte-macrophage colony-stimulating factor (GM-CSF). We have purified the pp135 by using GST-Grb2/Ash affinity column and have isolated the full-length complementary DNA (cDNA) encoding the pp135 using a cDNA probe, which was obtained by the degenerate polymerase chain reaction based on a peptide sequence of the purified pp135. The cloned cDNA has 3,958 nucleotides that contain a single long open reading frame of 3,567 nucleotides, encoding a 1,189 amino acid protein with a predicted molecular weight of approximately 133 kD. The deduced amino acid sequence reveals that pp135 is a protein that has one SH2, one SH3, and one proline-rich domain. The pp135, which contains two motifs conserved among the inositol polyphosphate-5-phosphatase proteins, was shown to have the inositol polyphosphate-5-phosphatase activity. The pp135 was revealed to associate constitutively with Grb2/Ash and inducibly with Shc using UT-7 cells stimulated with GM-CSF. In the cell lines derived from human chronic myelogenous leukemia, pp135 was constitutively tyrosine-phosphorylated and associated with Shc and Bcr-Abl. These facts suggest that pp135 is a signaling molecule that has a unique enzymatic activity and should play an important role in the signaling pathway triggered by GM-CSF and in the transformation of hematopoietic cells caused by Bcr-Abl.

Of the GATA-binding proteins, only GATA-4 selectively regulates the human IL-5 gene promoter in IL-5 producing cells which express multiple GATA-binding proteins

Interleukin-5 (IL-5) is produced by T lymphocytes and known to support B cell growth and eosinophilic differentiation of the progenitor cells. Using ATL-16T cells which express IL-5 mRNA, we have identified a region, within the human IL-5 gene promoter, that regulates IL-5 gene transcription. This cis-acting sequence contains the core binding motif, (A/T)GATA(A/G), for GATA-binding family proteins and thus suggests the involvement of these family members. In this report, we describe the cloning of human GATA-4 (hGATA-4) and show that hGATA-4 selectively interacts with the -70 GATA site within the IL-5 proximal promoter region. By promoter deletion and mutation analyses, we established this region as a positive regulatory element. Cotransfection experiments revealed that both hGATA-4 and PMA/A23187 stimulation are necessary for the IL-5 promoter activation. The requirement of another regulatory element called CLE0, which lies downstream of the -70 GATA site, was also demonstrated. ATL-16T cells express mRNA of three GATA-binding proteins, hGATA-2, hGATA-3 and hGATA-4, and each of them has a potential to bind to the consensus (A/T)GATA(G/ A) motif. However, using ATL-16T nuclear extract, we demonstrated that GATA-4 is the only GATA-binding protein that forms specific DNA-protein complex with the -70 GATA site. The electrophoretic mobility shift assay with extracts of COS cells expressing GATA-binding proteins showed that GATA-4 has the highest binding affinity to the -70 GATA site among the three GATA-binding proteins. When the transactivation ability was compared among the three, GATA-4 showed the highest activity. These results demonstrate the selective role of GATA-4 in the transcriptional regulation of the IL-5 gene in a circumstance where multiple members of the GATA-binding proteins are expressed.

Swine influenza virus strains recognize sialylsugar chains containing the molecular species of sialic acid predominantly present in the swine tracheal epithelium

We determined the ratio of N-glycolylneuraminic acid (Neu5Gc) to N-acetylneuraminic acid (Neu5Ac) in swine respiratory epithelia by fluorometric high-performance liquid chromatography, and examined the binding specificity of swine influenza virus strains for gangliosides containing different molecular species of sialic acid (Neu5Ac and Neu5Gc), and for bovine erythrocyte sialoglycoprotein 2 (GP-2) containing Neu5Gc as its predominate sialic acid (96% of total sialic acids). The presence of Neu5Gc, which had not been detected in human tracheal epithelia, and Neu5Ac in swine tracheal epithelia was observed in a 1:1 ratio. The swine influenza virus H1 and H3 isolates tested, except for A/swine/Iowa/15/30 (H1N1), displayed a marked binding ability for sialylsugar chains containing Neu5Gc compared with that of the human influenza virus strains. These results suggest that swine influenza viruses recognize sialylsugar chains containing the molecular species of sialic acid present predominantly in the swine tracheal epithelium.

Inhibition of highly metastatic FBJ-LL cell migration by ganglioside GD1a highly expressed in poorly metastatic FBJ-S1 cells

For clarification of the functions of gangliosides on tumor metastasis, examination was made of the ganglioside patterns of poorly metastatic FBJ-S1 and highly metastatic FBJ-LL cells. FBJ-S1 cells expressed GM3 and GD1a, whereas FBJ-LL cells expressed GM3 and slightly expressed GD1a. The capacity for FBJ-LL cells to migrate was ten times that of FBJ-S1 cells, but decreased by a half by pretreatment with GD1a. GD1b or GT1b had the same effect as GD1a, and synthetic sialyl compounds to a lesser extent, suggesting that gangliosides contain more than two sialyl residues to inhibit the migration of FBJ-LL cells.

[Morphological development of the intrinsic laryngeal muscles in rat--a scanning electron microscopic and histochemical study]

The postnatal development of the subneural apparatus (SNA) and differentiation of muscle fibers of the intrinsic laryngeal muscles (ILMs) in the rat were investigated on the 1st, 5th, 15th, 30th and 90th days after birth. The cricothyroid (CT), thyroarytenoid (TA) and posterior cricoarytenoid (PCA) muscles in the ILMs were examined. Furthermore, we compared the development of these muscles with that of the skeletal muscles of the hindlimb, the extensor digitorum longus (EDL) and soleus (SOL) muscles. The SNA was observed with a scanning electron microscope. The SNA was quantitatively analyzed by use of two parameters: the ratio of the length of the secondary synaptic cleft to its maximal width (L/W ratio) and the ratio of the area of the secondary synaptic clefts to that of the primary synaptic cleft(s) (ASC/APC ratio). The muscle fiber types were classified according to the density of each muscle fiber by the ATPase stain. On the 15th postnatal day, the SNAs of the CT and TA muscles had a tendency to show more advanced development than those of the PCA muscle. The SNAs of the ILMs appeared to develop earlier than those of the EDL and SOL muscles. The L/W and ASC/APC ratios of the ILMs inclined to be higher than those of the hindlimb muscles. On the 30th day, the SNAs of the PCA muscle were still immature, while those of the CT and TA muscles had become nearly mature. The EDL muscle showed completely mature development and outstripped the ILMs. In contrast, the SNA of the SOL muscle was the least mature of all muscles. The L/W ratios of the ILMs were not significantly different from each other, while the ASC/APC ratio of the PCA muscle was significantly lower than those of both the CT and TA muscles. The L/W and ASC/APC ratios of the EDL muscle were the highest of all muscles examined and those of the SOL muscle were the lowest. The muscle fiber types were not significantly different in the ILMs throughout the course. On the 30th day, the EDL muscle had reached the mature adult proportion of the muscle fiber types, while the ILMs and SOL muscle needed further development. Phylogenetically, the TA muscle appeared as a sphincter of the lower airway and then the PCA muscle, as a dilator, appeared. The CT muscle arose after separation of the thyroid and cricoid cartilages. These findings infer that the lag in development of the PCA to the TA muscle in early postnatal life was due to the importance of the protective function of the lower airway and the phylogenetical difference. Moreover, these results suggest that the ILMs, which are indispensable for sucking, develop early in life, followed by rapid development of the EDL muscle to start quadruped walking after the 15th day. Thus, different muscles need to develop as an animal grows because distinct functions of muscles are necessary for normal living. In conclusion, the ILMs may have a specific mode of postnatal development in contrast with those of the hindlimb muscles.

Hyaluronidase activity in gynaecological cancer tissues with different metastatic forms

We investigated hyaluronidase activity in gynaecological normal and malignant tissues. Hyaluronidase activity in culture medium of tissue specimens was detected by hyaluronic acid zymography and quantified by densitometry. Hyaluronidase activity was shown as one dominant band (molecular weight 65 kDa) at pH 3.5. Hyaluronidase activity was significantly higher in normal ovary (P < 0.05) and normal endometrium (P< 0.05) than in normal cervix. One dominant 65-kDa hyaluronidase was expressed in 100% (14 out of 14) of ovarian cancer tissues and in 91% (10 out of 11) of endometrial cancer tissues. However, hyaluronidase activity was not observed in cervical cancer tissues. Hyaluronidase activity was significantly higher in ovarian (P < 0.001) and endometrial (P < 0.01) cancer tissues than in cervical cancer tissue and was significantly higher in ovarian cancer tissue than in endometrial cancer tissue (P < 0.05). These facts suggest that the cancer cells make use of the original characteristic of the organ to invade and metastasize. Moreover, these results reflect the difference in metastatic forms and are suggestive of a strong relationship between hyaluronidase activity and invasion and metastasis of ovarian and endometrial cancers compared with cervical cancer.

[CT-guided localization for thoracoscopic pulmonary wedge resection]

Recently the identification of small-sized peripheral lung lesions has rapidly increased due to advancements in roentgenology. But for smaller lesions, definitive diagnoses by means of transbronchial or percutaneous biopsy have become more difficult. So we must resort to thoractomic or thoracoscopic biopsy. However, for thoracoscopic surgery palpation is inadequate, so the identification of deep or small lesions is difficult. Thoracotomy seems to be too invasive when used only for examination and not for therapy. Therefore, we tried CT-guided localization for thoracoscopic pulmonary wedge resection. Thus far we have performed CT-guided localization in 24 cases. Immediately prior to thoracoscopic surgery we placed marking devices in or beside the lesions after percutaneous puncture. As marking devices we used Kopans spring hook wire or a Naruke point marker. Pathological diagnoses of these lesions indicated 13 primary lung cancers (11 adenocarcinomas, 1 carcinoid, 1 squamous cell carcinoma), 4 focal fibroses, 2 metastases of renal cell carcinoma, 1 hamartoma, 1 tuberculoma, 1 cryptococcosis, 1 interstitial pneumonia, and 1 subpleural lymph node. The tumor diameters at their greatest dimension ranged from 3 to 33 mm (9.0 +/- 6.6 mm). The distance from the viceral pleura to the tumor surface ranged from 0 to 24 mm (10.9 +/- 6.7 mm). In one case pneumothorax occurred due to the shallow position of the tumor and the loss of the marking device. If these problems (pneumothorax, bleeding, loss of marking devices and others) are prevented, CT-guided localization should be performed as soon as possible before surgery. The identification of small peripheral lesions can almost be determined by CT now, so such identification may be the most reliable technique to employ during surgery.

Existence of a muscle spindle on the posterior cricoarytenoid muscle of the guinea pig

We examined a muscle spindle in the posterior cricoarytenoid muscle of the adult guinea pig. The spindle capsule contained three intrafusal muscle fibres. At the equatorial region, three intrafusal fibres did not form a typical aggregation of nuclei such as bags and chains observed in common mammalian muscle spindles. Two intrafusal fibres of the three were innervated by sensory endings which branched and arranged irregularly. These sensory endings lay on the surface of intrafusal fibres in shallow grooves or deeply penetrated into the fibre. The third intrafusal fibre, lacking sensory innervation, showed a similar fine structure to extrafusal fibres. These findings suggest that the muscle spindle in the posterior cricoarytenoid muscle of the guinea pig is strikingly different in the structure of intrafusal fibres and in the arrangement of sensory endings from that in common mammalian skeletal muscles. The occurrence and role of these different structures were discussed.