Dermatomycosis and environment]

Environments may act as reservoirs for pathogenic fungi, a determinant of the establishment of fungal infection, or an exacerbating factor of disease. In recent years, skin disease caused by geophilic fungi has been decreasing, while case reports of zoonoses from various animals are increasing. Outbreaks of anthropophilic T. tonsurans infection pose a problem to medical mycologists. Tinea pedis is the most common exogenous dermatomycosis in Japan. Although T. rubrum is presumed to be the dominant pathogen of this disease, T. mentagrophytes is detected more frequently from various environments, so far, the reason for this discrepancy has not been fully understood. The latest knowledge about the route of dermatophyte foot infection is as follows: (1) Dermatophyte propagules disseminated from patients may contaminate not only bath-mats but also wood floors, Japanese style mattings, concrete floors, slippers, cushions, etc., and from them adhere to healthy skin. (2) The agar stamping method can easily detect dermatophytes from the skin and the environment. (3) Propagules of T. mentagrophytes can survive for more than three months under certain conditions such as in rubber boots. (4) In order to eliminate dermatophytes gathered in socks and footwear, simple procedures (washing, bathing with hot water, or wiping with a towel) are all effective. (5) Prior application of an antifungal agent promptly eradicates dermatophyte propagules adhering to the skin from the environment. The author also mentioned the possibility of asymptomatic dermatophyte colonization, and the high prevalence of dysgeucia in oral carriers of Candida albicans.     

Chromosomal Mapping of Genetic Locus Associated with Thymus-size Enlargement in BUF/Mna Rats

The thymoma-prone rat of the BUF/Mna strain is a useful model for human thymoma. In this strain thymoma development is regulated by a single autosomal susceptible gene, Tsr-1. At pre-thymoma age, BUF/Mna rats have extremely large thyrauses, when compared to those of other strains of rats. Genetic studies in crosses between BUF/Mna rats with large thymuses and WKY/NCrj rats with small thymuses suggested the presence of a major autosomal gene, Ten-1 , which contributes to thymus enlargement in a backcross population. Linkage studies between Ten-1 and microsatellite markers in backcross rats of (WKY/NCrj×BUF/Mna)Fl×BUF/Mna have led to the localization of Ten-1 in chromosome 1. This result may provide an approach to clone Tsr-1 , which could be allelic to Ten-1.     

Morphologic and metabolic studies on the effect of ethane-1-hydroxy-1, 1-diphosphonate (EHDP) on the epiphyseal plate and metaphysis of the rat

Ethane-1-hydroxy-1, 1-diphosphonate (EHDP) has been widely used in recent clinical and laboratory investigations. The author examined epiphyseal and metaphyseal morphology as well as cartilage matrix and calcium metabolism during EHDP administration and after drug discontinuation by 35S, 45Ca and 3H-thymidine autoradiographic study. The effect of low-dose EHDP was limited to osteoclast dysfunction of the metaphysis with resultant widening of trabeculae. High dose administration of EHDP induces a variety of disorders with a manifestation of marked widening of the epiphyseal growth plate. This process is probably derived from a reduction in matrix calcification that relates an inhibition of chondrocyte metabolism with a resultant decreased rate of chondroitin sulfate turnover. Furthermore, high dose EHDP causes a metaphysis which exhibits rickets+-like changes with little calcification and a decrease in the normal rate of osteoprogenitor cell differentiation to osteoblasts and osteocytes.     

The role of glutathione on placental amino acid transport (using microvillous membrane vesicles)

To elucidate the role of glutathione (GSH) on placental amino acid transport, we investigated L-lysine transport using microvillous membrane vesicles prepared from full term human placenta. 1. The transport of L-lysine into microvillous membrane vesicles was not affected by glutathione. 2. The transport of L-lysine into microvillous membrane vesicles was inhibited by inorganic mercury (Hg2+), and 0.1mM Hg2+ inhibited 34% of this transport and 1mM Hg2+ inhibited 50%. 3. The transport of L-lysine inhibited by Hg2+ was almost completely restored when glutathione was added simultaneously. These results indicated that glutathione defended the inhibitory action of inorganic mercury on L-lysine transport across microvillous membrane.     

Anti-bacterial defense mechanism of the urinary bladder. Role of mannose in urine

Bacterial adherence to mucosa is thought to be an initial and important stage to cause urinary tract infection. Among some mechanisms of bacterial adherence, the role of fimbriae and its receptor is worthy of notice. In particular, type 1 fimbriae, for which mannose is assumed as a receptor, is reported as the most common type and called "common fimbriae". Therefore if a certain amount of mannose is present in urine, it will cover the fimbriae of bacteria and competitively block the bacterial adherence to bladder mucosa. As the first step, we tried to detect mannose in urine by high performance liquid chromatography (HPLC). Sugar can be measured by detecting the fluorescence which is produced by a sugar separated by ion exchange, reacting with arginine at high temperature. The results using standard sugar samples should have highly stable retention time and concentration curve with the minimum detectable mannose concentration of 0.02 microgram. We investigated mannose in urine from 186 cases. Since the mannose peak was often masked by near unidentified peaks, the peak of mannose could be detected only in 80 cases and its concentration could be measured only in 24 cases. Mannose concentration in the urine of the 24 cases was between 2.6 and 108.7 micrograms/ml and in most of cases it was lower than 20 micrograms/ml. Secondary, we examined the possibility of a mannose in urine to prevent bacterial adherence to mucosa by the hemagglutination test using guinea pig erythrocytes and type 1 fimbriated E. coli.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atrial natriuretic peptide in human urine

Summary A highly sensitive radioimmunoassay to measure atrial natriuretic peptide (ANP) concentration in urine has been established, and its clinical usefulness is presented. ANP in urine was stable at 4° C for several days and was easily measured by our radioimmunoassay. The average ANP excretion in 65 healthy persons was 25.0±1.4 ng/day (mean ± SEM) and the fractional excretion of ANP was 0.7±0.05%. In 14 patients with congestive heart failure, the average ANP excretion was 119.2±29.4 ng/day, which decreased to 53.3±11.0 after successful treatment.Abbreviations ANP atrial natriuretic peptide - hANP human atrial natriuretic peptide - RIA radioimmunoasay - NSB non specific bound - FE_ANP the fractional excretion of atrial natriuretic peptide - FE_Na the fractional excretion of sodium - SIADH the syngrome of inappropriate secretion of antidiuretic hormone     

Immunoelectron microscopic observations of hypothalamic TRH-containing neurons in rats

Summary Immunoreactive TRH-containing neurons and their synaptic associations were studied electron microscopically in the paraventricular nucleus (PVN) and dorsomedial nucleus (DMH) of the rat hypothalamus. In propylthiouracil (PTU)-treated rats, the immunoreactive cell bodies in the PVN appeared to be activated, showing a hypertrophic perikaryon, well developed Golgi bodies and numerous secretory granules. No such alterations were evident in the TRH neurons in the DMH. These findings suggest that the PVN-TRH neurons are involved in the hypothalamic-hypophysial-thyroid axis. Further, it was shown that unlabeled nerve terminals containing small and large clear vesicles make synaptic contacts with the TRH perikarya in the PVN. Thus it is likely that PVN-TRH neurons are regulated both by thyroid hormones and by other neuronal signals. In the DMH, unlabeled nerve terminals containing small and large clear vesicles, and immunoreactive terminals form synapses with TRH neurons. Thus the DMH-TRH neurons may be under dual neuronal control. It was further noted that in the DMH and PVN, TRH nerve terminals make synaptic contacts with other unlabeled neurons. It is evident that TRH acts as a neurotransmitter or neuromodulator, although the origin of TRH terminals should be elucidated.