Development of renal potassium excretion capacity in the neonatal rat

We investigated the capacity of newborn rats to excrete an acute potassium load to understand the development of a renal potassium excretion system. Three groups of the rats (7-14 d) were used to collect urine periodically over 6 h after oral infusion of potassium: control (no potassium loading) and low- and high-potassium-loaded rats. In the low-potassium-loaded group, infused with about 0.6 microEq of potassium chloride/g body wt., the rate of renal potassium excretion increased from 0.08 plus minus 0.02 (7 d) to 0.13 plus minus 0.02 (10 d) and 0.21 plus minus 0.03 (14 d) microEq/h/g body wt. The high-potassium-loaded rats (1.5-2.8 microEq/g body wt. potassium load) excreted potassium at a higher rate of 0.18 +/- 0.05 (7 d), 0.30 +/- 0.02 (10 d), and 0.45 +/- 0.10 (14 d) microEq/h/g body wt. They excreted 77% (7 d), 76% (10 d), and 95% (14 d) of the potassium load. These values were much larger than the rate of 0.026 microEq/h/g body wt. of the control rats and of 0.08 microEq/h/g body wt., a mean potassium excretion rate during development from 7 to 14 d calculated from the data in the previous study (Kanno T et al.: J. Pediatr. Gastr. Nutr. 24: 242-252, 1997). In the same period, serum potassium concentration in the newborn rats decreased significantly (p < 0.01) from 7.2 +/- 0.1 (7 d) to 6.7 +/- 0.1 mEq/l (14 d). All these results suggest that a renal potassium excretion system in the rat develops at least in the second week of life, and its capacity is high enough to excrete the daily potassium intake.     

Tissue distribution of the Pk antigen as determined by a monoclonal antibody

Using an anti-Pk monoclonal antibody (mAb) designated CPK-1, the expression of the Pk antigen was assessed on normal human tissue from non-Pk individuals. Although the Pk antigen was detected on fibroblasts and blood vessels as previously reported, it was also found on smooth muscle cells of the digestive tract and the urogenital system. Pk was also found on glandular cells of the stomach, oesophagus and prostate. Additionally, CPK-1 reacted weakly with oesophagus squamous cells, and a small number of glomeruli and tubules in the kidney. The mechanism of expression of the Pk determinant in non-Pk individuals is discussed.     

The effects of prostaglandin E1 on the pepsin activities in gastric mucosa and juice.

Prostaglandin E1 elevated pepsin activity in gastric mucosa but lowered pepsin activity in the gastric juice of rats treated by pylorus ligation and intragastric administration of hydrochloric acid. In these animals zymogen granules with low electron density were numerous in the gastric chief cells following prostaglandin E1 treatment. The prostaglandin E1-induced increase in mucosal pepsin activity was slightly inhibited by actinomycin D and there was no apparent increase in 3H-thymidine incorporation into gastric mucosa following treatment with prostaglandin E1. It is suggested that prostaglandin E1 causes an elevation of pepsin activity in the gastric mucosa by stimulating pepsin synthesis and perhaps also by facilitating pepsin release from zymogen granules. However, it also appears to inhibit pepsin release from the mucosa into the gastric cavity judging by the decrease of pepsin activity in gastric juice. The reduced pepsin activity in gastric juice may account, in part, for the reported anti-ulcerative action of prostaglandin.     

Molecular weight determination and fractionation of poly(L-histidine) by gel filtration

Dextran gel filtration (using Sephadex G-75 gel) with a continuous monitoring system was applied to the determination of the molecular weight and for fractionation of poly(L -histidine), poly[imino-1-(4-imidazolylmethyl)-2-oxoethylene], (PLH). PLH was eluted satisfactorily with a pH 2,35 buffer, whereas it was adsorbed to the gel with a pH 5,40 buffer. The weight-average and number-average molecular weights (M_w and M_n) were determined from the calibration plot of molecular weight, obtained with proteins, and corrected by the Smith method. A highly fractionated “monodisperse” PLH with M_w/M_n = 1,14 to 1,22 was obtained from PLH with M_w/M_n = 1,43 by the use of a pH 4,95 acetic acid/ammonium acetate buffer.     

Metabotropic glutamate receptors are associated with non-synaptic appendages of unipolar brush cells in rat cerebellar cortex and cochlear nuclear complex

Unipolar brush cells (UBCs) are a class of small neurons that are densely concentrated in the granular layers of the vestibulocerebellar cortex and dorsal cochlear nucleus. The UBCs form giant synapses with individual mossy fibre rosettes on the dendrioles which make up their brush formations and are provided with numerous, unusual non-synaptic appendages. In accord with the glutamatergic nature of mossy fibres, our previous post-embedding immunocytochemical studies indicated that various ionotropic glutamate receptor subunits are localized at the post-synaptic densities of the giant synapses, whereas the non-synaptic appendages are immunonegative. On the contrary, the metabotropic glutamate receptors mGluR1 and mGluR2/3 are situated at the non-synaptic appendages and are lacking at the post-synaptic densities. Other authors, however, have shown that antibodies to these metabotropic receptors stain both appendages and post-synaptic densities. In the present study, we have re-evaluated the distribution of metabotropic glutamate receptors in the UBCs of the cerebellum and the cochlear nuclear complex by light and electron microscopic pre-embedding immunocytochemistry with subtype-specific antibodies. We confirm that UBCs dendritic brushes are densely immunostained by antibody to mGluR1 particularly in the cerebellum and that antibody to mGluR2/3 labels at least a percentage of the UBC brushes in both the cerebellum and cochlear nuclei. At the ultrastructural level, it appears that mGluR1 and mGluR2/3 immunoreactivities are not associated with the post-synaptic densities of the giant mossy fibre–UBC synapses, but instead are concentrated on the non-synaptic appendages of the cerebellar UBCs. The non-synaptic appendages, therefore, may be an important avenue for regulating the excitability of UBCs and mediating glutamate effects on their still unknown intracellular signal transduction cascades. We also show that the pre-synaptic densities of UBC dendrodendritic junctions are mGluR2/3 positive. As previously demonstrated, antibodies to mGluR1 and mGluR2/3 label subsets of Golgi cells. Antibody to mGluR5 does not stain UBCs in the cerebellum and cochlear nucleus and reveals the somatodendritic compartment of Golgi cells situated in the core of the cerebellar granular layer, whilst cochlear nucleus Golgi cells are mGluR5 negative.     

Control of feeding rhythm in the terrestrial slug Incilaria bilineata

A modulatory neuron of feeding rhythm was newly identified in the buccal ganglia of the isolated central nervous system (CNS) of the terrestrial slug Incilaria bilineata. This neuron was termed the “feeding rhythm modulator” (FRM). Its morphological and electrical properties were compared with those of the MGC (metacerebral giant cell, a cerebral modulatory neuron of feeding rhythm). There was no direct connection between FRM and MGC. In order to investigate the control mechanism of the buccal central pattern generator, feeding rhythm was observed by varying the activities of MGC and FRM simultaneously. At a lower level of activity of MGC, feeding rhythm was not only sensitive to the activity of MGC but also to that of FRM. As the level of activity of MGC increased, feeding rhythm was exclusively controlled by the activity of MGC, and became unaffected by the activity of FRM. This indicates that cerebral neurons such as MGC primarily control feeding rhythm and modulate the contribution of FRM in a hierarchical manner.     

Increase in insulin response to glucose in the rat chronically treated with clonidine

Summary Effect of chronic clonidine treatment on the response to glucose of rat pancreatic B-cells was investigated. Clonidine treatment was carried out for 10 days by dissolving the drug into drinking water at a concentration of 10 g/ml. Control rats were given drug-free tap water. Serum insulin responses to glucose (750 mg/kg, i. v.) of clonidinetreated rats were much smaller than those of control rats. However, after 1 day's withdrawal of clonidine, the rise in the serum insulin level induced by glucose was approximately 2-fold larger in clonidine-treated rats as compared to that in control rats. Since clonidine treatment decreased body weight of the rat by 10%–20% in 10 days, the same experiments were carried out with rats whose body weight loss was made comparable to that of clonidine-treated rats by restricting food for 10 days. Then, some animals of the group thus treated had food-restriction discontinued for 1 day. In both of the above two groups, no increment in glucoseinduced rise in serum insulin level was observed. Islets of Langerhans isolated from clonidine-treated rats showed pronounced insulin releasing capacity in response to glucose. Insulin content per islet of the clonidine-treated rat was slightly larger than that of control rat. These results indicate that the enhancement of serum insulin response to glucose following clonidine treatment is mainly attributable to the hyper-responsiveness developed in the pancreatic B-cells.     

Brighton epistaxis balloon: application for cranio-facial injury

Head injury patients often complicate facial and/or multiple injuries other than cranio-cerebral insults and perplex the emergency staffs. The authors used Brighton epistaxis balloon for such patients with massive nasal bleeding and reported the utility of the balloon not only in such state of emergency but also for a few days to control the hemorrhage mostly caused by craniobasal fractures or rupture of the adjacent vessels. One hundred and twenty-nine patients were transported and hospitalized in Department of Emergency Medicine, University of Tokyo Hospital, Tokyo, Japan during the period from October, 1981 to January, 1983. Nasal bleeding was noted in 29 cases of them and the balloon was used in 10 cases, who were from 19 to 76 years of age, all males and suffered from basal fractures or craniofacial injuries. Six cases of them were also accompanied with fractures in the extremities or pelvis, hemopneumothorax and/or intra-abdominal bleeding and could not but put on "Military anti-shock trousers" for the management of hypovolemic shock, hence the nasal bleeding should be managed immediately in the emergency room. In these situations the balloon was inserted into both nasal cavities in all the patients, to control successfully the nasal hemorrhages one of which contaminated cerebrospinal fluid and three of which were sure to be pulsatile due to arterial injury. The Brighton epistaxis balloon is to be removed within twelve or twenty-four hours, but in the authors' cases the mean duration for the hemostasis was 58.9 hours for 6 survivors and 49.6 hours for all 10 cases.(ABSTRACT TRUNCATED AT 250 WORDS)     

Can random bladder biopsies be eliminated after bacillus Calmette–Guérin therapy against carcinoma in situ?

Purpose

Intravesical bacillus Calmette–Guérin (BCG) is the standard of care for bladder carcinoma in situ (CIS). The response to BCG therapy against CIS is generally assessed by random bladder biopsy (RBB). In this study, we examined the necessity of routine RBB after BCG therapy.

Methods

We retrospectively identified 102 patients who were initially diagnosed with CIS with or without papillary tumor and received subsequent 6–8-week BCG therapy. Thereafter, all patients underwent voiding cytology analysis, cystoscopy, and RBB to evaluate the effects of BCG therapy. We evaluated the association between clinical parameters (voiding cytology and cystoscopy findings) and the final pathological results by RBB specimens.

Results

According to the pathological results of RBB, 30 (29%) patients had BCG-unresponsive disease (remaining urothelial carcinoma was confirmed pathologically) and 20 were diagnosed with CIS. Positive/suspicious voiding cytology and positive cystoscopy findings were well observed in patients who had BCG-unresponsive disease compared with their counterparts (p?=?0.116, and p?<?0.001, respectively). The sensitivity (Sen.), specificity (Spe.), positive predictive value (PPV), and negative predictive value (NPV) of voiding cytology were 50%, 68%, 39%, and 77%, respectively. The values for cystoscopy findings were as follows: Sen.: 87%, Spe.: 57%, PPV: 46%, and NPV: 91%. The values for their combination (having either of them) were as follows: Sen.: 100%, Spe.: 44%, PPV: 43%, and NPV: 100%.

Conclusion

RBB after BCG therapy for patients with negative voiding cytology and negative cystoscopy may be omitted because their risk of BCG-unresponsive disease is significantly low (NPV: 100%).

     

ADAMANTINOMA OF THE TIBIA A Case Report and a Statistical Review of Reported Cases

A case of adamantinoma of the tibia is reported. A 70-year-old man complained of a painful swelling over the lower front of the right tibia. Roentgenograms showed an oval well-circumscribed, multilocular cystic lesion. Curettage and bone grafting were performed, and 17 months later the patient is in good condition. Microscopically the tumor tissue consisted mainly of epithelial Islands with a palisading at the periphery and a loose reticular pattern in the center of the tumor cell nests, showing a close resemblance to the ameloblastoma of the jaw bones. Electron micrographs revealed the epithelial nature of the tumor cells, i.e., a continuous basal lamina, desmosomes and bundles of microfilaments, probably tonofilaments. One hundred fifty six cases of this peculiar primary skeletal bone tumor previously reported in the literature were reviewed and discussed.