Differential expression of decorin and biglycan genes during palatogenesis in normal and retinoic acid-treated mice.

Proteoglycans are involved in secondary palate formation. In the present study, we focused on two small leucine-rich proteoglycans, decorin and biglycan, because they assembled extracellular matrix molecules such as collagens and modulated signaling pathway of transforming growth factor-beta. To investigate the functions of decorin and biglycan in palatogenesis, we compared their mRNA expression patterns between normal palate and retinoic acid-induced cleft palate in mice by using in situ hybridization analysis during the period of embryonic day 13.5 (E13.5) to E15.5. On E13.5, decorin mRNA was expressed in the epithelia and mesenchyme on the nasal side of the developing secondary palate. During the period the palate shelves were fusing (E14.5), decorin mRNA was strongly expressed in the mesenchyme but its expression pattern was asymmetric; decorin mRNA expression area in the nasal side was broader than that in the oral side. The expression of decorin mRNA was hardly detected in the mesenchyme on either side of the medial edge epithelium. After fusion (E15.5), its expression converged to the mesenchyme just around the palatine bone. Biglycan mRNA was ubiquitously distributed throughout the palatal mesenchyme for the mid-gestation period. Its expression area became limited to the ossification area within the palate after the late gestation period. In the retinoic acid-treated mice, the area of the decorin gene expression expanded to the core region of the palate primordium where little signal was observed in control mice. On the other hand, biglycan in the retinoic acid-treated mice did not show remarkable change in its distribution patterns compared with that in the control mice. These findings suggest that decorin and biglycan play distinct roles in palatogenesis, and decorin was more actively involved in the process of secondary palate formation than biglycan. Up-regulation of decorin gene expression in the retinoic acid-treated mice might influence the pathogenesis of cleft palate.     

Identification of genotypes of Cryptosporidium parvum isolates from ferrets in Japan

Recent molecular studies show that Cryptosporidium parvum is composed of at least eight genotypes including zoonotic genotypes. Therefore, it is important to screen the genotypes of the isolates harbored in animals for the control of human cryptosporidiosis. The ferret is a popular pet, but also a reservoir of Cryptosporidium. Since the infectivity of zoonotic genotypes in ferrets remains unclear, there is a possibility these hosts harbor zoonotic genotypes. In the present study, we examined the genotypes of C. parvum isolates from ferrets in Japan using polymerase chain reaction direct sequencing. The sequences of the isolates examined clustered with the ferret-adapted genotype (ferret genotype). Our study suggests that ferrets harbor the ferret genotype which is conserved across geographical areas. Further study is required to determine whether ferrets are a significant reservoir for human cryptosporidiosis.     

Study of Pax6 mutant rat revealed the association between upper incisor formation and midface formation.

In this study, we investigated the process of supernumerary upper incisor formation in the Pax6 mutant rat, rSey(2)/rSey(2), which exhibits a facial cleft between the medial nasal and maxillary processes. Histological investigation and epithelial labeling studies of wild type rat embryos indicated that the upper incisor develops by fusion of two primary dental placodes (PDPs) in the medial nasal process with a contribution from the epithelium of the maxillary process. In the rSey(2)/rSey(2) embryo, both PDPs are formed but they stay apart, then subsequently these PDPs independently develop into upper incisor tooth buds. In order to examine if the failure of the two placodes to fuse is due to the cleft between the maxillary and medial nasal processes, maxillary and medial nasal process fusion was inhibited with a barrier in wild type embryos. This resulted in the maintenance of the two distinct PDPs. These results demonstrate that fusion of the facial processes reduces the number of odontogenic placodes and is required to assemble all components at one site for rat upper incisor formation. The results also provide further insight into the mechanism of supernumerary incisor formation in human cleft lip conditions.     

Tetanus antitoxin levels in various Japanese age groups in 1989

The nationwide DPT vaccine program was started in 1969 for infants under 12 months of age. In order to estimate the tetanus immune status among the general population of various age groups, we measured the serum tetanus antibody level in randomly selected outpatients from Metropolitan Tokyo (n = 211, 6 months-60 years) and Hamamatsu, a city of 510 thousand population (n = 128, 3 years-80 years) between January 1987 and June 1989. Among the 211 subjects from Tokyo, the antibody value exceeding effective level of 0.01 HAU/ml was observed in 102 subjects (48.3%). The antibody positive rate was 90.8% in subjects of 3 to 21 years and was 27.7% in subjects of 22 years or older. The positive rate was significantly higher in subjects of 21 years or younger (p less than 0.005). Among 128 subjects from Hamamatsu, 60 (46.1%) had a positive antibody and the antibody positive rare was 96.9% in subjects of 3 to 21 years and was 29.5% in subjects of 21 years or younger (p less than 0.005). The above findings indicate that our DPT vaccination program has been functioning well for the last 20 years and that the immunized population is adequately protected against tetanus.     

Editorial comment: feasibility of central gastrectomy for gastric cancer

BACKGROUND: Central gastrectomy (CG) for gastric cancer was developed to preserve pyloric function and maintain a large gastric volume. Whether this procedure is feasible for limited cases of gastric cancer is unclear. METHODS: On the basis of Union Internationale Contre le Cancer TNM classification, pathologic characteristics, perioperative parameters, and long-term results, we analyzed 100 patients who underwent CG. RESULTS: Pathologic findings included T1 (tumor depth, mucosal or submucosal) in 82 patients and T2 (muscularis propria or subserosal) in 18 patients. Mean number of dissected lymph nodes was 17.3, and pathologic N1 (node metastasis, 6 or less) was found in 14 patients. There were no operative deaths, but 5 patients had postoperative complications: anastomotic leakage in 1, severe gastric stasis in 2, ischemic gastric ulcer in 1, and intra-abdominal bleeding in 1. No patient had a cancer recurrence in a mean follow-up of 49 months. New early gastric cancer was detected in 3 patients during follow-up endoscopic examination. The 5-year cumulative survival was 0.97. One year after CG, 63 patients had early satiety after food intake. Mean ratio of 1-year postoperative/preoperative body weight was 95%. CONCLUSIONS: Central gastrectomy with sufficient node dissection resulted in good long-term survival and minimal postoperative weight loss. CG is a safe and useful procedure for selected patients with gastric cancer, although close follow-up for recurrence and a more precise analysis on physiologic states is needed.     

Three presenile patients in which neuropsychological and neuroimaging examinations suggest possible progression to dementia with Lewy bodies

We report three presenile patients who were initially suspected of having Alzheimer's disease (AD) or being in the prodromal stage of AD, regardless of visuoperceptual dysfunctions in daily living, because they lacked the core features and prodromal non‐motor symptoms of dementia with Lewy bodies. Subsequently, progression to dementia with Lewy bodies was suspected based on neuropsychological and neuroimaging findings; additionally, one of the three patients suffered from visual hallucinations. Neuropsychological examinations such as subjective contours, cube copying and block design in the Wechsler Adult Intelligence Scale‐III revealed visuoperceptual dysfunction in all three patients even when other cognitive functions were rather preserved. Brain magnetic resonance imaging revealed no significant brain atrophy, including in the parieto‐occipital area and the hippocampus, while brain ¹⁸F‐fluorodeoxyglucose positron emission tomography demonstrated right dominant metabolic reductions in the occipital lobe, including the primary visual cortex, in all three patients. We suggest the possibility of progression to dementia with Lewy bodies, but not AD or posterior cortical atrophy. Regardless of the presence of core features and prodromal non‐motor symptoms, this progression is suggested when there are difficulties only in higher‐level visual processing such as subjective contours and block design in the Wechsler Adult Intelligence Scale‐III, no significant atrophy of the parieto‐occipital area and hippocampus on brain magnetic resonance imaging, and hypometabolism in the occipital lobe including the primary visual cortex on brain ¹⁸F‐fluorodeoxyglucose positron emission tomography.     

Three-way bipolar forceps: a novel bipolar coagulator system for nerve stimulation and detection of nerve potentials

Preoperative characterization of brain anatomy by magnetic resonance imaging and intraoperative functional characterization of the nervous system is essential in patients undergoing radical resection of brain tumors. A novel integrated system was developed combining conventional bipolar forceps with an electric stimulator and an oscilloscope. The system consists of a mechanical switching circuit allowing a wide range of electric characteristics and was designed to perform intraoperative electrophysiological studies, including functional mapping and measurements of motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs). This system achieved a significant reduction in exchange time (from 3.63+/-1.00 sec to 1.12+/-0.42 sec) between coagulation and stimulation, and reproducible measurement of MEPs from porcine limbs by cortical stimulation using the bipolar forceps. Functional mapping under awake craniotomy was carried out by cortical stimulation in patients with glioblastoma, and median nerve SEPs with high signal-to-noise ratio were elicited from the bipolar forceps on the sensory cortex of patients under general anesthesia. This integrated system is technically easy to operate and allows functional monitoring of an area that would otherwise be difficult to access using conventional methods. This three-way bipolar forceps system may reduce postoperative complications in patients undergoing neurosurgical procedures.     

Bacteriology of acute otitis media in Japanese children

Bacteriologic investigations were performed on 100 children with acute otitis media by culturing the fluid from a myringotomy site. Patients ranged in age from 7 months to 14 years, and 91 were younger than 6 years old. Bacterial isolates were yielded from cultures in 83 cases, and mixtures of two or three organisms were obtained from 15 patients. Among the total of 100 isolates, the most predominant organism was Streptococcus pneumoniae (28), followed by Hemophilus influenzae (26), Staphylococcus aureus (19), and Streptococcus pyogenes (six). Minimal inhibitory concentrations (MICs) of ampicillin sodium against S pneumoniae and H influenzae were 0.016 to 0.032 and 0.25 to 0.5 mg/L, respectively. None of the strains of H influenzae were resistant to ampicillin. The MICs of dicloxacillin sodium, cephalexin monohydrate, cefaclor, and erythromycin to H influenzae were 8 to 32, 8 to 16, 2 to 8, and 2 to 8 mg/L, respectively. The preferred drug for acute otitis media would be ampicillin in Japan, but we have to consider antistaphylococcal antibiotics for the patients who do not respond to 48 hours of treatment.