Traumatic degeneration of transected myelinated fibers of the mouse sciatic nerve.

Traumatic degeneration of myelinated fibers was studied by electron microscopy over 5 days following transection of mouse sciatic nerve. Special attention was paid to the mechanism which separates the degenerating part, while preserving the viable part of the axon. Immediately after transection, the opened end of the proximal stump revealed extensive subcellular changes including the disorganization of neurofilaments, and disruption of mitochondria and axonal endoplasmic reticulum (SER). Subsequently, vesicles of round and tubular profiles filled up the whole area of the stump end, and proximal to it appeared a neurofilament-predominant area characterized by randomly oriented neurofilaments and normally appearing mitochondria and SER. Characteristic membranous demarcations occurred in early periods at the border between the vesicle accumulation and the neurofilament-predominant areas, and later also within these areas. The demarcation membranes formed both by invagination of the surface plasma membrane and, probably, by fusion of the large vesicles. These became prominent with time, dividing the axoplasm into compartments of varying sizes, which gradually underwent degeneration and were liberated from the parent axon. Occurrence of autophagic vacuoles was characteristic of the degenerating portions of the parent axon. Thus, by the function of demarcation membranes, the parent axon to be preserved could remain membrane-bound, while the degenerating parts were shed off.     

Clinical evaluation of a potassium nitrate dentifrice for the treatment of dentinal hypersensitivity

Abstract The effectiveness of a 5% potassium nitrate dentifrice as a daily home treatment for dentinal hypersensitivity was evaluated in a double-blind study in 36 Japanese subjects who complained of cold and/or tactile hypersensitivity. The subjects were divided into 2 groups, with 18 being given a 5% potassium nitrate dentifrice (treated group) and the other 18 a vehicle paste (control group). Both groups were instructed to brush their teeth 2 × a day. The hypersensitivity levels of the affected teeth were assessed by 2 stimuli, one tactile and the other cold air, and by the perception of pain. The results of all 3 assessment methods indicated that the potassium nitrate dentifrice significantly decreased the level of hypersensitivity at weeks 4, 8, and 12. In the treated group, a rapid decrease of positive scores for both the cold air stimulus and the subjective symptoms appeared from week 2. Although a significant decrease of the assessment score was also observed in the control group, the reduction rate of the score was much greater in the treated group by ail 3 assessment methods at weeks 4, 8, and 12. Complete relief of subjective symptoms throughout the 12 weeks’examination was noted in 67% of the subjects in the treated group, but in only 6% in the control group. These results suggest the usefulness of a 5% potassium nitrate dentifrice in Japanese patients with dentinal hypersensitivity.     

Intracytoplasmic Lumina in Human Oviduct Epithelium

Intracytoplasmic lumina (ICL) in human oviduct epithelium were investigated with transmission electron microscopy. ICL were found in 43 out of 60 cases examined. They were ultra-structurally characterized by microvilli lining the lumina, periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining-positive finely granular material in the lumina, and secretory vesicles in the cytoplasm surrounding the lumina. Although ICL were observed at various heights within the epithelium, they were mainly seen in basally located cells that did not face the oviduct lumen. Various stages of formation and development of ICL were observed in the basally located epithelial cells with secretory activities. Primary ICL were originated in the cytoplasm where the secretory granules were aggregated with smooth-surfaced tubular vesicles. Electron microscopic observations after PA-TCH-SP staining revealed that ICL were formed by fusion of the secretory granules with the tubular vesicles. ICL were enlarged into round profiles by further fusion of secretory granules and tubular vesicles, and subsequently opened to the oviduct lumen, or fused to each other to develop into large extracellular cysts within the epithelium.     

Clinical results of intraperitoneal hyperthermic perfusion combined with surgery in patients with peritoneal recurrence from gastric cancer

Six patients with peritoneal recurrence after radical operation for gastric cancer were treated by an intraperitoneal hyperthermic perfusion (IPHP) combined with surgery (IPHP group). Immediately after surgery, a 2-hour IPHP was performed, using a perfusate containing 10 micrograms/ml of MMC, warmed at the inflow temperature of 46.5 +/- 1.1 degree C. Within the same period of time, 5 patients with intra-abdominal recurrent gastric cancer (control group) were treated by an intraperitoneal administration of MMC 10 mg combined with surgery. These 11 patients had malignant peritoneal effusion and, although in 3 of the control group, ascitic effusion did re-accumulate rapidly soon after surgery, the 6 patients of IPHP group did not re-accumulate post-hyperthermically. The average survival duration of IPHP group is 13.6 +/- 10. 6 months, whereas that for controls is 3.0 +/- 2.1 months. Again, the survival rate for IPHP group surpassed that for controls at p = 0.012 and p = 0.008, in a generalized Wilcoxon method and Logrank method, respectively. Post-hyperthermically, hypoproteinemia and thrombocytopenia occurred transitorily. These results show that IPHP using MMC combined with surgery is a safe, reliable treatment for patients with peritoneal recurrence due to gastric cancer.     

A new strategy for management of retroperitoneal tumors with supradiaphragmatic vena caval thrombi

A new surgical technique to treat retroperitoneal tumors with supradiaphragmatic vena caval invasion is described. In this technique, hepatic warm ischemia can be avoided with reversed hepatic outflow through the portal vein and neither hypothermic circulatory arrest nor cardiopulmonary bypass is necessary using centrifugal blood pump-driven bypass.     

Cell surface phenotype of in vitro proliferating lymphocytes in HTLV-I-associated myelopathy (HAM/TSP)

The in vitro proliferation of peripheral blood lymphocytes (PBLs) without any mitogenic stimulation is one of the hallmarks of human T lymphotropic virus type I (HTLV-I) infection. Recent evidence suggests a difference in the degree of the phenomenon between HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and asymptomatic HTLV-I carriers (AC). In this article, we demonstrated several alterations in the features of the in vitro transformed lymphocytes between patients with HAM/TSP (n = 16) and AC (n = 8). The percentages of total CD8+ and CD8+CD28+ cells were significantly increased in the in vitro proliferating T lymphocytes derived from the patients with HAM/TSP when compared to those from AC. HAM/TSP was segregated from AC by the high degree of the proliferation of CD8+CD28+ cells. The expression of HTLV-I-specific antigens on the cultured PBLs was detected only in the subjects which showed low CD8+CD28+/CD4+ ratio of the in vitro proliferating lymphocytes. These findings suggest that this phenomenon distinguishes HAM/TSP from AC, not only in quantity but also in quality.     

Effect of Oral Administration of A Prostacyclin Analog (Op-41483) On Pulmonary Function and Bronchial Responsiveness in Stable Asthmatic Subjects

To examine whether prostacyclin has an attenuating effect on nonspecific bronchial responsiveness in asthma, we measured provocative concentration of methacholine producing a 20% fall in forced expiratory volume in 1 second (PC₂₀-FEV₁) before and after oral administration of a chemically stable prostacyclin analog (OP-41483) (200 μg 4 times a day for 4 days) in 8 patients with stable asthma. Neither baseline pulmonary function nor PC₂₀-FEV₁ significantly improved after the treatment. These results suggest that prostacyclin may have no direct effect on bronchial responsiveness in asthmatics. Further studies using more potent and long-lasting prostacyclin mimetic will be needed to confirm the conclusion.     

Preparation and Characterization of a Murine Monoclonal Antibody (MDR3M) Reactive with mdr3 Gene Product

A murine monoclonal antibody (MDR3M) (isotype: IgM) reactive with mdr3 gene product was generated by immunizing mice with mdr3 -specific peptide (H₂N-¹²WRPTSAEGDFELGISSKQKRKKTKTVKMI⁴¹G-COOH) and hybridizing the primed mouse splenic B cells with X63-Ag8,6.5.3 mouse plasmacytoma cells. MDR3M did not cross-react with mdr1 gene product. This monoclonal antibody may be useful for analyzing the role of mdr3 gene product in cells and tissues.     

Significance of low perfusion with increased oxygen extraction fraction in a case of internal carotid artery stenosis.

BACKGROUND AND PURPOSE: Decreased cerebral blood flow with an increased oxygen extraction fraction, the so-called misery perfusion syndrome, suggests a vulnerability to reduction in cerebral perfusion pressure and a tendency to develop cerebral infarction. It is uncertain, however, whether the infarct would occur in the brain region specifically exhibiting this condition. CASE DESCRIPTION: We report the case of a patient with right intracranial internal carotid artery stenosis who presented with mild left hemiparesis resulting from a right frontal watershed infarct. Positron emission tomography 2 months after the stroke showed decreased cerebral blood flow with an increased oxygen extraction fraction in noninfarcted areas of the affected hemisphere. Maximal changes were detected in the watershed area between the middle cerebral artery and the posterior cerebral artery. Three months later, while on antiplatelet therapy, he suffered a new infarct in the right temporo-occipital watershed area that had shown the highest oxygen extraction fraction value on the first positron emission tomographic study. One month after the recurrence of stroke, a second study showed that low perfusion with increased oxygen extraction fraction persisted in the affected hemisphere to a lesser degree than in the first study. CONCLUSIONS: This observation suggests that the area of low perfusion exhibiting the highest oxygen extraction fraction has the highest risk for infarction. Increased oxygen extraction fraction may be an important factor in the development of hemodynamic infarction.     

Low frequency of p53 gene mutation in tumors induced by aflatoxin B1 in nonhuman primates.

Aflatoxin B1 has been suggested as a causative agent for a G to T mutation at codon 249 in the p53 gene in human hepatocellular carcinomas from southern Africa and Qidong in China. To test this hypothesis, nine tumors induced by aflatoxin B1 in nonhuman primates were analyzed for mutations in the p53 gene. These included four hepatocellular carcinomas, two cholangiocarcinomas, a spindle cell carcinoma of the bile duct, a hemangioendothelial sarcoma of the liver, and an osteogenic sarcoma of the tibia. None of the tumors showed changes at the third position of codon 249 by cleavage analysis of the HaeIII enzyme site at codon 249. A point mutation was identified in one hepatocellular carcinoma at the second position of codon 175 (G to T transversion) by sequencing analysis of the four conserved domains (II to V) in the p53 gene. These data suggest that mutations in the p53 gene are not necessary in aflatoxin B1 induced hepatocarcinogenesis in nonhuman primates. The occurrence of mutation in codon 249 of the p53 gene in selective samples of human hepatocellular cancers may indicate involvement of environmental carcinogens other than aflatoxin B1 or that hepatitis B virus-related hepatitis is a prerequisite for aflatoxin B1 induction of G to T transversion in codon 249.