Vascularization in vivo caused by the controlled release of fibroblast growth factor-2 from an injectable chitosan/non-anticoagulant heparin hydrogel

Addition of various heparinoids to the lactose-introduced, water-soluble chitosan (CH-LA) aqueous solution produces an injectable chitosan/heparinoid hydrogel. In the present work, we examined the capability of the chitosan/non-anticoagulant heparin (periodate-oxidized (IO(4)-) heparin) hydrogel to immobilize fibroblast growth factor (FGF)-2, as well as the controlled release of FGF-2 molecules from the hydrogel in vitro and in vivo. The hydrogel was biodegraded in about 20 days after subcutaneous injection into the back of a mouse. When the FGF-2-incorporated hydrogel was subcutaneously injected into the back of both mice and rats, a significant neovascularization and fibrous tissue formation were induced near the injected site. These results indicate that the controlled release of biologically active FGF-2 molecules is caused by biodegradation of the hydrogel, and that subsequent induction of the vascularization occurs.     

Angioarchitectural study of esophageal varices

Summary Pathomorphological and angioarchitectural characteristics of esophageal varices, mainly of ruptured varices, were studied in autopsy cases. Contrast medium was injected into the esophageal vein in 25 among 75 cases with varices, and in 4 cases without varices as a control. Out of the 75 cases with varices, rupture was confirmed in 8 cases. Ruptured points were recognized at the oral end of the longitudinal veins (these veins were called sudare-like veins in this study) in the lamina propria at the lower end of the esophagus in all of the 8 cases. This ruptured area was called the critical area. By morphometric examination, dilatation of these sudare-like veins was the most obvious in severe varices, and these veins were observed to penetrate the muscularis mucosae to connect to the submucosal veins at the critical area. This area seemed to be of the greatest significance in the pathogenesis of spontaneous variceal rupture.     

Pathological Aspects of Radiofrequency Catheter Ablation of the Canine Atrioventricular Node and Bundle of His

Radiofrequency catheter ablation of the atrioventricular (AV) node or bundle of His was performed in 12 adult mongrel dogs. The aim was to create chronic incomplete AV block (first- and second-degree AV block) and to examine the histopathology of the ablated lesions. However, the late electrophysiological results (2 4 weeks follow up) were various: normal in 2 dogs, mild PR prolongation (< 50%) in 2 dogs, first-degree AV block (PR prolongation a 50%) in 2 dogs, second degree AV block in 2 dogs, complete AV block in 4 dogs. The maximally ablated area (%) of the atrioventricular conduction system in serial histologic sections from dogs with these conditions was 69%, 75%, 89.5%, 95% and 99.5%, respectively. The number of intact conduction cells at the maximally ablated site varied from 6 to 30 in the four cases of incomplete AV block. The mean ablated volume (%) of either the AV node or penetrating His bundle correlated roughly with the degree of AV block. The ablated lesions were well demarcated and almost replaced by dense fibrous tissue at 4 weeks. Interruption (3 dogs) or thinning (1 dog) of the endocardial elastic lamellae was detected, in association with endocardial thickening (mean 913 μm). Endocardial thrombi were found in 3 dogs (2 fresh, 1 organized). We conclude that radiofrequency catheter ablation does not cause severe complicated lesions. Several possible conditions for creating chronic incomplete AV block are discussed. Acta Pathol Jpn 41: 487–498, 1991.     

Mutagenicity of the bile of dogs with an experimental model of an anomalous arrangement of the pancreaticobiliary duct

To learn the reasons for the high incidence of biliary carcinomain patients with anomalous arrangement of the pancreaticobiliaryduct (APBD) mutagenicity of the bile of APBD-modeled dogs thathad received a dorsal pancreatico-cholecystostomy was assayedby the Ames Salmonella mutation test. The bile from two outof 18 APBD dogs was mutagenic for Salmonella typhimurium strainTA98 under the condition of metabolic activation by rat liverS9 fraction, while the bile from 17 normal dogs was not mutagenic.Furthermore, the bile from five APBD dogs i.p. administered1-nitropyrene (1-NP), which is a typical environmental mutagen,was more mutagenic for strain TA98 than that from 1-NP-treatednormal dogs. The bile from the APBD dogs had very high amylaseactivity, indicating that the bile contained pancreatic juiceas a result of the pancreatico-cholecystostomy. When pancreaticjuice from a normal dog was added to the bile from 1-NP-treatednormal dogs, mutagenicity of the bile increased 1.6- to 2.0-fold.Furthermore, sulfatase increased the mutagenic activity of thebile in the presence of the pancreatic juice. HPLC revealedthat the bile from a 1-NP-treated APBD dog contained mutagenic1-nitro-6/8-hydroxypyrene and 1-nitro-3-hydroxypyrene, whilebile from a 1-NP-treated normal dog did not contain these deconjugatedproducts. The pancreatic juice from a normal dog had very high-glutamyltransferase (GGT) and aminopeptidase activities andlow sulfatase activity, but it had no ß-glucuronidaseactivity. In addition, the bacteria that easily infect the biliaryduct of APBD dogs, Escherichia coli, Klebsiella, Enterobacterand Proteus, had high ß-glucuronidase activity. Inparticular, Klebsiella showed a very high sulfatase activity.These results suggest that pancreatic juice enzymes and bacteriainfecting the biliary duct deconjugate the detoxified mutagensin the bile and induce mutagenicity of the bile from APBD dogsor APBD patients.     

Coronary artery bypass surgery in a patient with myasthenia gravis

A 73-year-old man with myasthenia gravis required quadruple coronary artery bypass grafting due to triple-vessel disease. Anesthetic management was performed with general anesthesia using a reduced dose of muscle relaxant with the aid of a neuromuscular transmission monitor. He was extubated 14 hrs after surgery without difficulty under this monitor. His postoperative course was uneventful. A patient with myasthenia gravis who required coronary artery bypass surgery was successfully performed by the deliberate preoperative evaluation of patient's myasthenic and cardiac status, and by the careful perioperative management.     

Obstruction of St Jude Medical valves in the aortic position: significance of a combination of cineradiography and echocardiography

BACKGROUND: Obstruction of the St Jude Medical valve (St Jude Medical, Inc, St Paul, Minn) is a rare but serious complication. METHODS: Cineradiographic and echocardiographic evaluations of aortic St Jude Medical valves were simultaneously performed on 54 patients, with no signs of prosthetic valve dysfunction late after surgery. RESULTS: Although closing angles of the leaflets corresponded closely with the manufacturer data, restricted opening of the leaflets (opening angle >/= 20 degrees ) was found in 16 (group D) of the 54 patients by means of cineradiography. The opening angles were equal to or less than 14 degrees in the other 23 patients (group N) and between 15 degrees and 19 degrees in the remaining 15 (group M). Doppler-derived transprosthetic pressure gradients were significantly higher (P =.03) and the velocity index was significantly lower (P =.003) in group D than in group N. However, no significant differences were found in those values between group N and group M. Replacement of the aortic St Jude Medical valves was performed in 5 of the 16 patients, and the remaining 11 have been followed up because of relatively low pressure gradients. The cause of restricted leaflet movement was pannus formation without thrombosis in 4 patients and valve thrombosis with pannus formation in one. CONCLUSIONS: Reduced valve orifice area and restricted opening of the leaflets resulting from excess growth of pannus probably led to obstruction of the aortic St Jude Medical valves. A combination of cineradiography and echocardiography makes it possible to provide an accurate and detailed diagnosis of obstruction of the valve.     

Repeated clenching causes plasticity in corticomotor control of jaw muscles

This study tested the effect of short‐term tooth‐clenching on corticomotor excitability of the masseter muscle using transcranial magnetic stimulation (TMS). Fifteen subjects with normal stomatognathic function participated. All subjects performed a tooth‐clenching task (TCT) on five consecutive days. The TCT consisted of 10, 20, and 40% of maximum voluntary contraction in a randomized order within 1 h. All subjects underwent TMS in four sessions: pretask day 1 (baseline), post‐task day 1, pretask day 5, and post‐task day 5. Motor‐evoked potentials (MEPs) from the masseter and the first dorsal interosseous (FDI) muscles were obtained using TMS in four sessions. Motor thresholds decreased, after the TCT, for the masseter muscle MEPs. Masseter muscle MEPs were dependent on stimulus intensity and on session, whereas FDI muscle MEPs were only dependent on stimulus intensity. Post‐hoc Tukey tests demonstrated significantly higher masseter muscle MEPs post‐task on day 5 with 80 and 90% stimulus intensity and above when compared with pre‐ and post‐task day 1 values. Our results suggest that the performance of repeated TCTs can trigger neuroplastic changes in the corticomotor control of the jaw‐closing muscles and that such neuroplastic changes may contribute to the mechanism underlying the clinical manifestations of tooth clenching.     

Intermittent bundle branch blocks in a patient with uncommon-type atrioventricular nodal reentrant tachycardia and enhanced atrioventricular nodal conduction

We report on a patient with uncommon-type atrioventricular (AV) nodal reentrant tachycardia with a short tachycardia cycle length (235-270 ms), in whom transient wide QRS tachycardia with both left bundle branch block and right bundle branch block aberrancy were followed by narrow QRS complexes. In addition, His-ventricular (H-V) block and a sudden prolongation of the H-V interval occurred during the tachycardia. As the determinant of these unusual findings, the possibility that the anterograde limb of the reentry circuit has an enhanced AV nodal conduction property is discussed, as is the clinical significance of this type of tachycardia.