Identification of the cell type origin of odontoma-like cell masses in microphthalmic (mi/mi) mice by in situ hybridization

Tooth abnormalities occur in microphthalmic (mi/mi) mice. The elongated odontogenic epithelium is interrupted by unresorbed bone at the basal end of the mi/mi incisor, with the epithelium gathered into cell clusters. These clusters develop to odontoma-like masses. To identify the origin of the cell types of these odontoma-like masses, the localization of osteonectin (Osn), osteocalcin (Osc), osteopontin (Osp), matrix Gla protein (MGP) and amelogenin (Am) mRNA in the process of tooth development in mi/mi and +/+ mice was investigated by means of in situ hybridization. Decalcified mandibles of neonatal, 5-, 10-, 14-day-old mice were examined. Osn and Osc mRNA, which localized in osteoblasts and odontoblasts, were also detected in the cells of odontoma-like masses in mi/mi mice. The cells expressing these mRNA were short, columnar and odontoblast-like. Am mRNA was detected in ameloblasts. In mi/mi mice, Am mRNA was also detected in ameloblastic cell clusters, which were formed by the tall columnar cells in the odontoma-like masses. No apparent Osp mRNA expression was detected in the masses. These results indicated that even in odontogenic abnormal cells resulting from physical obstruction in mi/mi mice, the genes that are involved in normal tooth development were still expressed.

Properties of a slow nonselective cation conductance modulated by neurotensin and other neurotransmitters in midbrain dopaminergic neurons

1. A widespread mechanism of slow excitation throughout the nervous system involves overlapping changes in nonselective ion conductance and K+ conductance. We used whole cell patch-clamp recording to characterize such a nonselective conductance induced by neurotensin (NT) and other neurotransmitters in immunocytochemically identified dopaminergic neurons cultured from the rat ventral tegmental area (VTA). 2. The NT-induced inward current consisted of an initial peak and later "hump." The response was blocked reversibly by the nonpeptide NT-receptor antagonist SR48692, suggesting that it resulted from activation of NT receptors. 3. The channel was almost equally permeable to Na+ and K+, as determined from the reversal potential shift upon switching from Na+- to K(+)-containing external solution. The permeability of Cs+ was similar to that of Na+, as determined from the zero-current equation and average reversal potential in the 75 mM Na+ solution. Cl- was not significantly permeable. 4. In Ca(2+)-free external solution, the NT-induced current showed a fourfold increase in amplitude, and in high Mg2+ (20 mM) external solution, the NT-induced current showed an 80% decrease in amplitude, suggesting that external Ca2+ and Mg2+ could block the nonselective conductance. 5. The NT response was unaffected by loading the neurons with either the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid or with 1 mM ca2+. The nonselective conductance was therefore not Ca2+ activated. 6. Loading the neurons with cyclic GMP or cyclic AMP (each with the phosphodiesterase inhibitor isobutyl-methylxanthine) did not affect the NT response. The NT-induced nonselective conductance was therefore not cyclic nucleotide-activated. 7. The latency of the NT response was long (> or = 185 ms, average 406 ms, 30 degrees C), indicating that NT did not induce the conductance through ligand-gated channels. Thus, NT activated a slow nonselective cation conductance. 8. Neurokinin B, a metabotropic glutamate agonist, and muscarine elicited responses similar to the NT response. The NT response could be elicited after desensitizing the responses to these other neurotransmitters, indicating receptor specificity in the activation of the nonselective conductance.

Angiomyolipoma arising in the colon

Extrarenal angiomyolipomas are very rare. Here we report the first case of surgically resected angiomyolipoma of the descending colon that developed in a 50-yr-old man. The patient had no signs of or family history of tuberous sclerosis. He underwent a partial colectomy because the tumor obstructed the colon. Histologically, the tumor consisted of three components: mature fat cells, blood vessels, and smooth muscle cells, and was thereby diagnosed as an angiomyolipoma. Immunohistochemically, the proliferating smooth muscle cells were positive for vimentin, alpha-smooth muscle actin, and desmin. The tumor cells were negative for HMB-45, which is consistently expressed in renal angiomyolipomas.

[The effects of preoperative transcatheter arterial chemoembolization (TAE) for the recurrence of hepatocellular carcinoma (HCC) from the viewpoint of consecutive tumor necrosis effect]

From 1990 to 1994, seventy-seven patients with HCC below 10 cm in tumor diameter underwent hepatic resections after TAE. They were divided into two groups: group C, complete necrosis (over 90% histologically at the maximum cutting surface of the specimen): group I, incomplete necrosis (under 90%). There were no significant differences in clinical background of patients, histopathological features and total disease-free survival rate (DFR) between the two groups. Nevertheless, DFR of patients in group C was significantly better than that of patients in group I, limiting the patients for curative resection. It was suggested that the recurrence of HCC after resection might be inhibited by curative operation following preoperative TAE with complete necrosis of tumor.

[Ten-year follow-up of percutaneous transluminal coronary angioplasty]

The long-term efficacy of percutaneous transluminal coronary angioplasty (PTCA) was evaluated in 124 patients who underwent PTCA between October 1982 and June 1985. Seventy-six patients had their proximal coronary arteries completely revascularized by PTCA (including repeat PTCA) and follow-up angiography showed the vessels were patent 3 to 6 months after the last intervention (group A). The other 48 patients showed incomplete revascularization (group B). The 10-year event-free survival rates from cardiac death and non-fatal myocardial infarction were 89.7% in group A and 93.5% in group B, respectively. Survival rates free from cardiac death, myocardial infarction, coronary bypass surgery, and repeat angioplasty for new lesions were 82.5% and 62.7%, respectively (p < 0.001). Ninety-nine percent of patients in group A and 79.5% of patients in group B were asymptomatic at the follow-up. Coronary angiography was performed in a total of 22 patients (19 patients in group A, 3 in group B). In group A, myocardial infarction occurred in one patient 8 years after PTCA. The infarct-related lesion seemed to be the same as the previous PTCA lesion. Although the other 20 PTCA lesions were all patent without progression, nine significant and new lesions were found on the coronary angiograms. Successfully revascularized vessels remained patent for over 10 years, but new lesions sometimes occur in segments other than the previously treated segment.

Effect of complement activation in human serum on isolated porcine islets

We investigated the effect of the activation of complement in human serum on isolated adult porcine islets using an in vitro model of pig-to-human islet transplantation. Pancreata were obtained from slaughterhouse pigs (6-8 mo old). Islets were prepared by intraductal collagenase digestion followed by purification on Ficoll gradients. The purified islets were incubated with xenogeneic human serum with or without heat inactivation for 45 min. As control, islets were incubated with autologous porcine serum. After the incubation, the islets' responsiveness to an acute glucose stimulus (5.5 mM, static incubation) was evaluated by measurement of the insulin content of the medium. Islets exposed to human serum showed significantly lower insulin secretory response than the control (1.76 +/- 1.17 microU/islet/120 min, without heat inactivation; 1.74 +/- 1.36 microU/islet/120 min, with heat inactivation; 3.39 +/- 0.92 microU/islet/120 min, control). No difference in insulin secretory response, however, was observed between islets exposed to human serum with heat inactivation and without. Furthermore, we evaluated the cytotoxic activity of human serum on porcine islets by a complement-dependent cytotoxicity using the MTT colorimetric assay, and found that the human serum had no complement-dependent cytotoxic activity against the islets. We concluded that the insulin secretion dysfunction of porcine islets exposed to human serum was not due to the activation of complement and there was no evidence of hyperacute rejection mediated by complement activation in the in vitro model of pig-to-human islet transplantation.

Ki-ras point mutations and proliferation activity in biliary tract carcinomas

The association between Ki-ras mutations and proliferation activity was investigated in a comprehensive series of biliary tract carcinomas (BTCs). We precisely microdissected samples of tissue from paraffin-embedded sections of 77 BTCs including 22 intrahepatic cholangiocarcinomas (ICCs), 36 extrahepatic cholangiocarcinomas (ECCs), and 19 gall bladder carcinomas (GBCs). Ki-ras mutations at exons 1 and 2 were determined by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method and confirmed by direct sequencing. Proliferation activity was immunohistochemically assessed to generate proliferating cell nuclear antigen labelling indices (PCNA LIs). Ki-ras mutations were detected in 10 of 22 ICCs (45%), 24 of 36 ECCs (67%), and in 16 of 19 GBCs (84%). The frequency of Ki-ras mutations in peripheral type ICCs was 33% (4 of 12) and that in the hilar type ICCs was 60% (6 of 10). In ECCs the highest value of 82% (9 of 11) was found for carcinomas located in the lower part of the biliary tree. Mean PCNA LI in mutation-positive BTCs was significantly elevated compared with the mutation-negative value. These results indicate frequent involvement of Ki-ras mutations in BTCs, especially in GBCs and in distal ECCs, and that carcinomas harbouring a mutation feature high cell proliferation activity.

[Role of reservoirs in intraarterial chemotherapy for recurrent hepatocellular carcinoma after hepatectomy]

We conducted a retrospective study on the role of reservoirs in intraarterial chemotherapy for recurrent hepatocellular carcinoma (HCC) after hepatectomy. Ninety-two out of 170 patients with HCC who underwent hepatectomy from 1987 to 1992 in our institute were enrolled in this study. HCC recurred in 55 patients. A rate of good patency of the catheter of the reservoir at the time of recurrence was found in 72.7% of the patients. Transcatheter arterial embolization (TAE) for recurrent tumor was not feasible in 3 patients, because of occlusion of the hepatic artery (3.3% of patients with reservoir, 5.5% of patients with recurrence). Eleven patients were treated by intraarterial chemotherapy using the reservoir and TAE or TAE and PEIT (group R), and 11 patients were treated only with TAE and/or PEIT (group NR). Although there were no significant differences between the two groups in the number of recurrent lesions and operative procedures, tumor-free interval was shorter in group R. Cumulative survival rates after recurrence were not significant. The frequency of TAEs was lower in group R, which shortened the hospitalization for postrecurrence therapy. Thus, intraarterial chemotherapy using reservoir contributed to improvement of the quality of life of patients with recurrent HCC.

Gq/11 and PLC-beta 1 mediate the substance P-induced inhibition of an inward rectifier K+ channel in brain neurons

1. Substance P (SP) induces a slow neuronal excitation in cholinergic neurons from the nucleus basalis by suppressing an inwardly rectifying K+ current (Kir). We have determined which G protein alpha-subunit mediates this SP effect. 2. After intracellularly injecting antibody against each alpha-subunit of G proteins (Gq alpha/11 alpha, G12 alpha, and G13 alpha) with an Eppendorf microinjector, we examined, by using the whole cell patch-clamp and the ON-cell mode of single-channel recording, the effect of SP on Kir in cultured neurons of the nucleus basalis. The effect of SP on Kir was substantially reduced in neurons injected with antibodies to Gq alpha/11 alpha but not with antibodies to G12 alpha or G13 alpha. 3. The effects of antibodies against three isozymes of phospholipase C (PLC-beta 1, PLC-beta 2, and PLC-beta 3) were tested. The SP-induced suppression of Kir was reduced by antibody against PLC-beta 1 but not by antibodies against PLC-beta 2 or PLC-beta 3. 4. We conclude that the SP-induced inhibition of Kir in nucleus basalis neurons is mediated by Gq/11 and PLC-beta 1.

Neural connection between the ventral portion of the lumbar intervertebral disc and the groin skin

This study was designed to investigate neural mechanisms of referred pain in lumbar intervertebral disc lesions. Patients with a degenerative disc in lower lumbar segments occasionally complain of groin pain, which cannot be explained anatomically as having a radicular origin. In rats pretreated with intravenous application of Evans blue dye, the dye extravasation appeared in the groin skin after application of capsaicin to the ventral portion of the L5-6 intervertebral disc. This response occurred even in rats with a sectioned L-5 spinal nerve and sympathetic trunks, but did not occur in rats with a sectioned genitofemoral nerve. Capsaicin topically applied to the sciatic nerve did not cause dye extravasation in the hindpaw. Therefore, groin dye extravasation was not due to a direct effect of capsaicin but, rather, presumably was caused by an "antidromic axon reflex" of dichotomizing C fibers or to a segmental sympathetic reflex causing vascular permeability. The present results indicate that the ventral portion of the lumbar discs is neurally connected to the groin skin via the upper (L-2) lumbar spinal nerves in rats. Groin pain coincident with low-back pain may be explained as referred pain, indicating that a lesion is present in the ventral portion of the lumbar intervertebral disc space.

[Growth of squamous cells lung cancer between alveolar basement membrane and alveolar epithelium]

We examined patterns of growth of cancer cells in specimens of alveoli taken from 41 patients with squamous cell carcinoma (36 men and 5 women, mean age 65 years). For comparison, 8 samples from patients with small cell carcinoma (6 men and 2 women, mean age 64) and 71 samples from patients with adenocarcinoma (48 men and 23 women, mean age 62) were also studied. The samples were fixed in formalin, embedded in paraffin, and then subjected to immunostaining. Glandular structures composed of non-atypical cuboidal cells with negative p53 staining and scanty positive PCNA staining were found in 90% of the samples of squamous cell carcinoma. In small cell carcinoma, 25% of the samples had small numbers of no-atypical glandular structures. In adenocarcinoma, no non-atypical glandular structures were seen. Glandular structures were observed in the periphery of the cancerous tissue. Some of these non-atypical cells were attached to the alveolar basement membranes. We conclude that squamous cell carcinoma grows between the basement membrane and the alveolar epithelium, and leaves noncancerous epithelium with glandular structure.

Enhancement of N-nitrosodiethylamine-initiated hepatocarcinogenesis caused by a colchicine-induced cell cycle disturbance in partially hepatectomized rats

The effects of a colchicine-induced M-phase block of regeneration after partial hepatectomy on early-stage liver carcinogenesis were studied in rats. When administered 1 or 3 days after N-diethylnitrosamine initiation and partial hepatectomy, colchicine increased the mitotic index of regenerating hepatocytes at days 4-6 without evidence of liver cell necrosis. When the protocol was combined with a selection procedure (E. Cayama et al., Nature (Lond.), 275: 60-62, 1978), a significant increase in the size but not number of gamma-glutamyltranspeptidase-positive foci at week 5 was observed in a colchicine dose-dependent manner. This was associated with an elevated incorporation of 5-bromo-2-deoxyuridine into the gamma-glutamyltranspeptidase-positive cells. In a longer-term experiment, the numbers, sizes, and 5-bromo-2-deoxyuridine labeling index of persistent nodules were increased significantly in colchicine-treated rats at week 9. This was associated with significant increases in the incidences and numbers of hepatocellular carcinomas at week 42. The above results raise the interesting possibility that a cell cycle disturbance in the early stage of liver carcinogenesis provides a persisting growth advantage for initiated cells, resulting in enhanced growth of foci and persistent nodules that evolve into hepatocellular carcinomas.

[Successful repair of right atrial rupture due to nonpenetrating trauma of the chest]

A 24-year-old male was brought to our hospital after being injured in a traffic accident. On arrival, his blood pressure was 70/44 mmHg and his pulse rate was 135/min and regular. Chest X-p revealed cardiomegaly but there was no pleural effusion or bone fracture. Echocardiogram revealed cardiac tamponade and he was diagnosed as cardiac rupture due to non penetrating trauma. Under midline sternotomy, right atrial rupture was repaired. The patient developed cardiac arrest lasting approximately 8 minutes during anesthetic induction, so he needed to be ventilated for 8 days. However his postoperative course was not so eventful and he was discharged 38 days after surgery without any neurophysiological disturbance.

In vitro-in vivo correlation of pharmacodynamics of felodipine in essential hypertensive patients based on an ion-channel binding model

The relationship between the plasma drug concentration and the antihypertensive effect of felodipine was analyzed by an ion-channel binding model which takes into consideration the slow association/dissociation process of a drug at the calcium channel. The in vitro dissociation constant (Kd) of felodipine to the calcium channel in the heart of rats was determined, and was compared to the in vivo dissociation constant (Kd,calc) estimated by the pharmacodynamic analysis of the concentration-effect data in Japanese essential hypertensive patients obtained from literature. The relative relationship between Kd and Kd,calc of felodipine was substantially identical with eight other calcium channel blocking agents reported previously. This results suggested the possibility that we can predict the pharmacodynamic behavior of newly developed calcium channel blocking agents from the in vitro Kd value and plasma concentration-time profile in human using the ion-channel binding model.

Increased nasal mucosal blood flow, airway resistance and secretion induced by electrical stimulation of the superior salivatory nucleus in cats

We studied the effects of electrical stimulation of the superior salivatory nucleus (SSN) on the nasal blood flow, nasal airway resistance, and nasal secretion in ketamine or pentobarbital anesthetized cats. The blood flow of the nasal mucosa was measured by laser Doppler flowmetry. Similar to the effects of stimulation of the parasympathetic nerve innervating the nasal mucosa, the SSN stimulation increased the nasal blood flow, nasal airway resistance, and nasal secretion on the ipsilateral side. These responses were not accompanied by changes in contralateral nasal blood flow, ipsilateral forelimb blood flow, blood pressure, or orofacial movement. Atropine administration partially inhibited the SSN-induced nasal vasodilation without interfering with the effect on the nasal airway resistance. This vasodilatation was not affected by sympathectomy or guanethidine administration, but it was abolished by hexamethonium administration. It is suspected that the cells in the SSN control both nasal vasodilatation and secretion, and that the SSN output fibers responsible for the nasal parasympathetic control consist of both cholinergic and non-cholinergic fibers.

Activation of G protein-coupled inward rectifier K+ channels in brain neurons requires association of G protein beta gamma subunits with cell membrane

In cultured noradrenergic neurons from the rat locus coeruleus, application of recombinant G protein beta 1 gamma 2 subunits (30 nM) to the cytoplasmic side induced single channel activity similar to the somatostatin-induced single channel activity of G protein-coupled inward rectifier potassium channels (Kir (G)). In contrast, recombinant GTP gamma S-activated, myristoylated alpha i2 (100 nM) did not activate this brain Kir (G). Application of beta 1 gamma 2 C68S (30 nM or 150 nM), in which the cysteine residue fourth from the carboxyl terminus of gamma 2 was replaced by serine, failed to activate the brain Kir(G). This mutant lacks prenylation which is required for the association of beta gamma subunit with the cell membrane. Thus, our results suggest that the association of beta gamma subunit with the cell membrane is a prerequisite for activating Kir(G) channels.

Occupation of the QB-binding pocket by a photosystem II inhibitor triggers dark cleavage of the D1 protein subjected to brief preillumination

The D1 protein of the photosystem (PS) II reaction center turns over very rapidly in a light-dependent manner initiated by its selective and specific cleavage. The cleavage of D1 was studied by using a PS II inhibitor, N-octyl-3-nitro-2,4,6-trihydroxybenzamide (PNO8), as a molecular probe. The following results were obtained. (i) D1 was selectively cleaved into 23-kDa N-terminal and 9-kDa C-terminal fragments in complete darkness by PNO8 at a single site in a D-E loop connecting membrane-spanning helices D and E. (ii) The cleavage was markedly enhanced when PS II was illuminated for a brief period before the addition of PNO8 in darkness. (iii) The effect of preillumination was slowly lost during incubation in the dark, with a decay half-time of approximately 1 h at 25 degrees C. (iv) The light intensity of preillumination required for the cleavage was much lower than that required for O2 evolution. (v) The light-triggered cleavage of D1 was observed in thylakoids, PS II membranes, and PS II core particles, but not in purified PS II reaction centers. More than 60% of D1 was cleaved into the two fragments with no other by-products. (vi) The cleavage reaction revealed a marked pH dependence that was considerably different from that for inhibition of PS II activity. The results are interpreted as indicating that the binding of PNO8 to the QB-binding pocket triggers proteolytic cleavage of D1 that has been previously modified during illumination.

CT-guided transthoracic needle biopsy: a comparison between automated biopsy gun and fine needle aspiration

AIMS

We retrospectively investigated the diagnostic accuracy and complication rate of transthoracic core biopsy using an automated biopsy gun and compared the findings with those of aspiration needle biopsy.

PATIENTS AND METHODS

Seventy-three patients underwent 74 core biopsy procedures and 50 patients underwent 52 aspiration biopsy procedures. Of these, a final diagnosis was obtained in 107 lesions with surgery or clinical course. Fifteen patients in which a final diagnosis was not obtained were excluded from the study on diagnostic accuracy. Thus, in the study of diagnostic accuracy, 63 core biopsy procedures for 62 lesions are included. Core biopsy was performed with an 18 G cutting needle using an automated biopsy gun. Aspiration biopsy was performed with a 20 G aspiration needle.

RESULTS

Core biopsy yielded sufficient material in 57/63 procedures (90.5%). A correct diagnosis was obtained in 36 procedures (85.7%) for malignant leisons and a specific benign diagnosis was obtained in 11 procedures (52.4%). Aspiration biopsy yielded a correct diagnosis in 26 procedures (81.3%) for malignant leisons and in seven (46.7%) for benign lesions. The overall correct diagnosis were 75.8% and 71.7% with core biopsy and aspiration biopsy, respectively. Core biopsy gave a higher predictive rate than that of aspiration biopsy for both benign and malignant lessons (P < 0.02). Pneumothorax occurred in 18/74 (24.3%) patients with core biopsy and in 18/45 (40.0%) patients with aspiration biopsy. Of these, three with core biopsy and two with aspiration biopsy needed tube drainage. The other complication was haemoptysis, which occurred in six patients following core biopsy and in three after aspiration biopsy. All nine cases subsided spontaneously. There were no fatal complications.

CONCLUSIONS

Core biopsy with a biopsy gun increase the diagnostic accuracy with a higher histologic predictive rate and no obvious additional risk of complications.