The effect of calcium gluconate and other calcium supplements as a dietary calcium source on magnesium absorption in rats

The effects of commercially available calcium supplements (calcium carbonate, calcium gluconate, oyster shell preparation and bovine bone preparation) and gluconic acid on the absorption of calcium and magnesium were evaluated for 30 days in male Wistar rats. There were no differences in the apparent absorption ratio of calcium among rats fed each calcium supplement; however, the rats fed the calcium gluconate diet had a higher apparent absorption ratio of magnesium than the rats fed the other calcium supplements. Dietary gluconic acid also more markedly stimulated magnesium absorption than the calcium carbonate diet, and the bone (femur and tibia) magnesium contents of rats fed the gluconic acid diet were significantly higher than those of the rats fed the calcium carbonate diet. Furthermore, the weight of cecal tissue and the concentrations of acetic acid and butyric acid in cecal digesta of rats fed the calcium gluconate diet or the gluconic acid diet were significantly increased. We speculate that the stimulation of magnesium absorption in rats fed the calcium gluconate diet is a result of the gluconic acid component and the effect of gluconic acid on magnesium absorption probably results from cecal hypertrophy, magnesium solubility in the large intestine and the effects of volatile fatty acids on magnesium absorption.

Multiple brain gas embolism after ingestion of concentrated hydrogen peroxide

We present a 63-year-old man who developed multiple brain infarction after ingesting a 35% hydrogen peroxide solution. Neurologic examination revealed left hemiparesis, primarily affecting the lower limb, and mild weakness of the right lower limb. Gadolinium-enhanced MRI revealed patchy bilateral brain lesions. Oxygen gas embolization is the likely cause of the brain infarctions.

[Hematological evaluation of megakaryocytic vacuolar degeneration in patients with idiopathic thrombocytopenic purpura]

Variable degrees of vacuolar degeneration of the cytoplasm of megakaryocytes(MEG) have been recognized in patients with idiopathic thrombocytopenic purpura(ITP). It has been questioned whether this degeneration is specific to the disease, as it is not seen in all patients, and few reports have examined its physiological relationship to the disease process. This study examined the vacuolation and its relationship to platelet count(PLTc) by image analysis, measuring the vacuolar area and the MEG area. However, it was inappropriate to evaluate the vacuolar area alone, since variations in the MEG area among patients influenced the vacuolar area. When the proportion of the vacuolar area relative to total MEG was defined as %VAC, the value for ITP patients was higher than in control cases (p < 0.05). However, there was no correlation between %VAC and PLTc. It was thought that this reflected the previous reports doubting the disease specificity of this feature. When all the ITP patients were generalized, the age at onset was wide, and both chronic type and repetitive type cases were included. However, in 4 ITP cases in which it was possible to follow the treatment progress, the %VAC was well correlated with the change in PLTc. It was concluded that MEG cytoplasmic vacuolation in ITP is morphologically meaningful if it can be followed over the course of treatment.

Pulmonary interstitial emphysema during piston-type high-frequency oscillatory ventilation

We retrospectively reviewed data on high frequency oscillatory ventilation (HFOV) settings and pulmonary function in 14 extremely low birth weight infants who were treated with piston-type HFOV immediately after birth for severe respiratory distress to investigate the cause of pulmonary interstitial emphysema (PIE) associated with HFOV. PIE developed a mean of 23 hr after the initiation of HFOV in 6 infants. Eight infants did not develop PIE and served as the control group. The lowest mean airway pressure (MAP) in the PIE group, which occurred immediately before disease onset was 5.2 cm H2O. The lowest MAP in the control group was 7.5 cm H2O (p < 0.01), which occurred immediately before the ventilatory mode was changed from HFOV to conventional mechanical ventilation for weaning from mechanical ventilation. Respiratory system compliance (Crs) 12 hr after birth was below normal in both groups and there was no significant difference between groups. These results suggest that an unusually low MAP may contribute to PIE during piston-type HFOV in the presence of low Crs. It is therefore important to maintain a high MAP during HFOV until pulmonary compliance becomes normal.

Overexpression of c-myc induces apoptosis at the prophase of meiosis of rat primary spermatocytes

Transgenic rats expressing the rat c-myc gene under the control of the human metallothionein II A promoter were produced. We found that the female transgenic rats were fertile, but that the male transgenic rats were sterile. Atrophy of the seminiferous tubules and depletion of sperm were observed in the sterile male testes. The expression of differential stage-specific mRNAs, including those of the c-kit receptor proto-oncogene, meiotic heat-shock protein 70 gene, acrosin gene, and transition protein 1 gene, was analyzed by the reverse transcriptase-polymerase chain reaction during spermatogenesis. The results suggested that spermatogenesis in these sterile rats were arrested at the prophase of meiosis in the primary spermatocytes. We found that apoptotic DNA fragmentation occurred in primary spermatocytes of the sterile transgenic rats. These results suggest that overexpression of the c-myc gene induces apoptosis at the prophase meiosis of the primary spermatocytes thereby causing male sterility in the c-myc transgenic rats.

Effects of beta 1-->4 linked galactooligosaccharides on use of magnesium and calcification of the kidney and heart in rats fed excess dietary phosphorous and calcium

Magnesium deficiency was induced in male Wistar rats by adding an excess of phosphorous and calcium to the diet (1.195 g of phosphorous and 1.04 g of calcium/100 g of diet). Feeding of these animals with a diet containing beta 1-->4 linked galactooligosaccharides (4'-GOS) (5 g of 4'-GOS/100 g of diet) increased the apparent magnesium absorption ratios and the concentrations of magnesium in the serum and femur, and reduced accumulation of calcium in the kidney and heart. We speculate that the use of magnesium increased by feeding 4'-GOS to a limited extent prevented the lower magnesium status and the severity of calcification of the kidney and heart caused by excess dietary phosphorous and calcium.

RB1 oncosuppressor gene over-expression inhibits tumor progression and induces melanogenesis in metastatic melanoma cells

The retinoblastoma gene (RB1) is frequently deleted or mutated in many tumor types and in all cases of retinoblastoma. Apart from its role in regulation of the cell cycle, the RB1 gene product (p110RB1) appears to be involved in control of differentiation. Malignant metastatic cells show many properties of poorly differentiated cells, and are highly invasive in vitro and in vivo. We have transfected the human RB1 cDNA in an expression vector under the control of the beta-actin promoter into B16F10 murine melanoma cells. These cells highly overexpress RB1 mRNA and the p110RB1 product, show reduced growth rate and increased melanogenesis in vitro. Vector control transfectants showed no alteration of invasiveness. The p110RB1 over-expressing cells also had a reduced capacity to migrate and invade through an artificial basement membrane, key characteristics of metastatic cells. When injected into nude mice, the p110RB1 over-expressing cells showed reduced tumor growth and reduced metastatic potential. The few metastasis observed were predominantly melanotic. These data indicate that RB1 gene expression is involved in melanoma cell differentiation and plays a role in downregulation of migration, invasion and metastatic potential of these cells.

Hepatitis and hepatocellular carcinoma in two prairie dogs (Cynomys ludovicianus)

In two blacktailed prairie dogs (Cynomys ludovicianus), hepatocellular carcinoma with metastasis to the lung, co-existing chronic active hepatitis, and hyperplasia of hepatocytes in the non-neoplastic areas of the liver tissue were observed. The hyperplastic hepatocytes had many eosinophilic inclusion bodies positive for orcein stain in their cytoplasm. Electron microscopy revealed areas of a specific mail-like mesh structure in the location of the cytoplasmic inclusion bodies. Ultrastructure of inclusion bodies differed from that of the hepadna virus usually associated with hepatocellular carcinoma, and hepadna virus-like particles were not observed.

Possible contributions of mastocytosis, apoptosis, and hydrolysis in pathophysiology of randomized skin flaps in humans and guinea pigs

To understand better the pathophysiology of random skin flaps, randomized skin flaps of human (3 cases) and guinea pig (53 cases) were investigated. Proximal (normal), proximomedial (viable), mediodistal (between viable and necrotic parts), and distal (necrosis) locations of the skin flaps were biopsied. Lipid peroxidase, hydrolytic enzymes of cytosol (Ca(2+)-dependent cysteine protease: calpain), and lysosome (acid phosphatase) of skin were used as markers. Measurements were taken of the flap blood flow; the numbers of capillaries, postcapillary venules, pericapillary arterioles, leukocytes, and mast cells per unit square of dermis. Apoptotic cells were identified by specific staining. Flaps were sampled at postoperative weeks 1 and 3 (human) and hours 1 and 6, and days 1 to 7 (guinea pig). The values for normal skin were regarded as the control. Obstruction (by leukocytes) of venous microvessels, rather than arterial microvessels, was the major cause of temporary hypoxia in the proximomedial location, constant hypoxia (venous stasis) in the mediodistal location, and ischemia in the distal location. Increases in the number of mast cells (mastocytosis) and microvessels (angiogenesis) were significant only in the viable parts of the flaps. This phenomenon and the rate of blood flow increased with time in viable locations (guinea pig). Epidermal necrosis, dermal fibrosis, and apoptosis were evident mostly in the mediodistal location. Elevated levels of leukocytes, lipid peroxidase, acid phosphatase, and calpain, combined with necrotic changes, were seen mostly in the distal skin location. There is a strong possibility that the following factors are involved: lipid piroxidation and hydrolysis in necrosis of the distal flap location after ischemia; constant hypoxia in fibrosis and apoptosis in the mediodistal location; and initial or temporary hypoxia in mastocytosis-induced angiogenesis in the viable location. The results presented here indicate that guidelines for further investigations include combined suppression of leukotaxis, lipid peroxidase, and hydrolysis, or the application of mast cell growth factors in an effort to salvage the flap maximally.

[Central alveolar hypoventilation syndrome with compression of the medulla oblongata by tortuous and elongated vertebral arteries]

A 43-year-old woman was admitted to the hospital with hypoventilation, which developed when she took sedatives because of an operation on an adrenal gland tumor. Central alveolar hypoventilation syndrome was diagnosed after neurophysiological and pulmonary-function tests. Magnetic resonance imaging and vertebral angiography revealed that tortuous and elongated vertebral arteries compressed the ventral sides of the medulla oblongata, which may have caused the hypoventilation. Mechanical ventilation during sleep improved her condition. Home mechanical ventilation was prescribed and she has been well during follow up as an outpatient.

Inhibition of agonist-induced Ca2+ entry in endothelial cells by myosin light-chain kinase inhibitor

Identification of the signal which links the depletion of Ca2+ stores to a Ca2+ entry pathway in the plasma membrane remains to be determined. In the present study, effects of ML-9 and wortmannin, inhibitors of myosin light-chain kinase (MLCK), on agonist-stimulated Ca2+ response were investigated in porcine aortic endothelial cells loaded with the Ca(2+)-sensitive dye fura-2. Bradykinin (BK) caused a rapid increase in [Ca2+]i, followed by a sustained increase due to the influx of Ca2+ from the extracellular space. ML-9 almost completely abolished the sustained increase in [Ca2+]i in BK-stimulated cells, while it did not affect the mobilization of Ca2+ from intracellular stores. ML-9 also abolished the sustained increase in [Ca2+]i caused by thapsigargin. Wortmannin mimicked the effect of ML-9 on the thapsigargin-stimulated Ca2+ response. These findings document for the first time the involvement of MLCK inhibitor in Ca2+ signaling in endothelial cells.

Effects of calcium gluconate on the utilization of magnesium and the nephrocalcinosis in rats fed excess dietary phosphorus and calcium

The effects of calcium gluconate on the utilization of magnesium and nephrocalcinosis in male Wistar rats made magnesium-deficient by adding excess dietary phosphorus (1.195 g of phosphorus/100 g of diet) and calcium (1.04 g of calcium/100 g of diet) were compared with the effects of calcium carbonate. The effects of dietary magnesium concentration on the magnesium status and nephrocalcinosis were also examined. Adding excess dietary phosphorus and calcium decreased the apparent magnesium absorption ratios and the concentrations of magnesium in the serum and femur and increased the deposition of calcium in the kidney, and the low magnesium condition (0.024 g of magnesium/100 g of diet) aggravated the deposition of calcium and the low magnesium status. The apparent magnesium absorption ratios and femur magnesium concentration in the rats fed a calcium gluconate diet (an equimolar mixture of calcium gluconate and calcium carbonate was used as a source of calcium) were significantly higher than in the rats fed a calcium carbonate diet (only calcium carbonate was used as a source of calcium), irrespective of dietary magnesium concentration. Dietary calcium gluconate lessened the accumulation of calcium in the kidney and increased the serum magnesium concentration compared with dietary calcium carbonate, when the rats were fed the normal magnesium diet (0.049 g of magnesium/100 g of diet) but not the low magnesium diet. We speculate that the increased utilization of magnesium by feeding the calcium gluconate diet to a limited extent prevented the low magnesium status and the severity of nephrocalcinosis caused by adding excess dietary phosphorus and calcium.

Cannabis 25 (1), biotransformation of cannabidiol and cannabidiolic acid by Pinellia ternata tissue segments

Two marihuana constituents, cannabidiol (1) and cannabidiolic acid (4) were each converted mainly to two metabolites using tissue segments of Pinellia ternata tuber. The structures of the metabolites formed from 1 were determined to be 1-Oβ-D-glucopyranoside and 1-Oβ-D-diglucopyranoside by (1)H nmr, (13)C nmr and fabms. Those from 4 were determined as 4-Oβ-D-glucopyranoside and 10'-hydroxyl 4-Oβ-D-glucopyranoside. In time course experiments, 1 was absorbed rapidly by the tissues and glucosylated. Hydroxylation subsequent to the glucosylation occurred at the pentyl group in 4.

Ciliary neurotrophic factor (CNTF) genotypes and CNTF contents in human sciatic nerves as measured by a sensitive enzyme-linked immunoassay

To study the level of ciliary neurotrophic factor (CNTF) in human nervous tissues, we developed a sensitive enzyme-linked immunoassay using a specific antibody against human CNTF. This method allowed us to detect as little as 0.3 ng/ml of human CNTF with good linearity and accuracy. Using this method, CNTF levels were determined in human sciatic nerves obtained at autopsy from 21 amyotrophic lateral sclerosis (ALS) patients and 48 subjects who had died of other neurological diseases. CNTF genotypes were also determined. The results indicated that CNTF levels were high in the normal homozygotes and approximately halved in the heterozygote subjects. There was, however, no significant difference in CNTF levels in the sciatic nerves between ALS and other neurological disease patients, indicating that the CNTF level was mainly determined by its genotypes and that the level in the sciatic nerves was not reduced in ALS patients.

[Role of the p53 gene in apoptosis]

Cell numbers are controlled by a homeostatic mechanism between cell growth, arrest and programmed cell death (apoptosis) in normal and cancerous tissues. One of the tumor suppressor genes, p53, functions as a transcription factor or transcriptional regulator through DNA and protein binding properties, and plays an important role in regulating cell cycle and induction of apoptosis. Although there are two apoptotic pathways, p53-independent and p53-dependent, the latter will be emphasized and discussed in this section. Since p53 is often inactivated due to mutation in human cancers, understanding the p53-dependent apoptotic pathway is extremely important. Analysis of p53-dependent apoptosis as well as apoptosis caused by other p53-related genes should provide a clue to a new strategy for cancer therapy.

Early myocardial lesions induced by cardiotoxic compounds in Sprague-Dawley rats

Early focal myocardial lesions in rats induced by five cardiotoxic compounds were histopathologically observed 1 hr and 4 hr after a single intravenous injection with 1/10 LD50 and LD50. The lesions were observed 1 hr and 4 hr after the treatment with LD50 of isoproterenol (ISP), 4 hr with 1/10 LD50 of ISP, 4 hr with LD50 of hydralazine (HYD), caffeine (CAF) and cyclophosphamide (CYC), but not with adriamycin (ADR). The lesions consisted of homogeneously intensely eosinophilic staining, contraction band formation and fragmentation of cardiac muscle fibers. The lesions were interspersed in the inner one third of the left ventricular walls including the papillary muscles with ISP, HYD and CAF, and were all over the ventricular myocardium with CYC.

Freeze substitution and freeze drying for stable, long-term preservation of cytologic specimens for immunostaining

OBJECTIVE

To develop a new method of fixing and preserving cytologic specimens for immunostaining after long-term storage at room temperature.

STUDY DESIGN

The method consists of three steps: fixation, freeze substitution or freeze drying, and storage. To test the method, we used the human small cell lung carcinoma cell line Lu-135, which expresses a high level of mutant p53 protein and exhibits strong nuclear staining when reacted with an anti-p53 antibody. A smear of Lu-135 cells was fixed in a mixture of methanol and ether (50:50=vol/vol) or sprayed with a fixative containing isopropyl alcohol, methanol and polyethylene glycol. The fixed cells were freeze substituted by immersing them in a dry ice/methanol/ether bath and then were freeze dried under a vacuum. The smear was then placed in a 50-mL conical tube containing silica gel. The tube was sealed and stored at room temperature.

RESULTS

Freeze substituted cells that were fixed with methanol/ether and stored for more than six months retained strong p53 positivity, as strong as that of the control cells, which had been fixed and stored in methanol.

CONCLUSION

Freeze substitution and freeze drying are an alternative method of preserving cytologic specimens.

Transfection of wild-type TP53 induces differentiation in human gingival carcinoma cells

We investigated the effects of transfection of wild-type TP53 on the growth properties of a human gingival carcinoma cell line, KOSC-3, in which the TP53 gene is mutated at codon 248 and overexpressed. The wild-type TP53 expression plasmid, pCDM8-p53/neo and the control plasmid, pCDM8/neo, were each stably transfected into KOSC-3 cells by using the calcium phosphate method. The number of G418-resistant colonies from wild-type TP53-transfected cells was approximately half that from plasmid controls. Exogenous wild-type TP53 transcripts were identified in four of the 20 G418-resistant clones analysed by reverse transcription PCR. Although the growth rates of the wild-type TP53+ clones did not drastically change during log phase, their saturation density was significantly reduced. The wild-type TP53+ cells were morphologically flat and enlarged when cultured in vitro, and were less able to form colonies in soft agar. In nude mice, the wild-type TP53+ clones formed subcutaneous tumours with conspicuous keratinisation and notable cell death that was not manifested in the parental and plasmid control cells. These findings indicate that the wild-type TP53 gene, even when it coexists with a mutated form, may function as a growth suppressor and differentiation inducer under restricted conditions in gingival squamous cell carcinoma.

EGF or PDGF receptors activate atypical PKClambda through phosphatidylinositol 3-kinase

Overexpression of a TPA-insensitive PKC member, an atypical protein kinase C (aPKClambda), results in an enhancement of the transcriptional activation of TPA response element (TRE) in cells stimulated with epidermal growth factor (EGF) or platelet-derived growth factor (PDGF). EGF or PDGF also caused a transient increase in the in vivo phosphorylation level and a change in the intracellular localization of aPKClambda from the nucleus to the cytosol, indicating the activation of aPKClambda in response to this growth factor stimulation. These immediate signal-dependent changes in aKPClambda were observed for a PDGF receptor add-back mutant (Y40/51) that possesses only two of the five major autophosphorylation sites and binds PI3-kinase, and were inhibited by wortmannin, an inhibitor of PI3-kinase. Furthermore, an N-terminal fragment of the catalytic subunit of PI3-kinase, p110alpha, inhibited aPKClambda-dependent activation of TRE in Y40/51 cells stimulated with PDGF. Overexpression of p110alpha resulted in an enhancement of TRE expression in response to PDGF and the regulatory domain of aPKClambda inhibited this TRE activation in Y40/51 cells. These results provide the first in vivo evidence supporting the presence of a novel signalling pathway from receptor tyrosine kinases to aPKClambda through PI3-kinase.

Transgene expression in mammary glands of newborn rats

Transgene expression in the mammary glands of newborn rats was studied to establish an early selection system for transgenic animals producing exogenous proteins in their milk during lactation. A fusion gene composed of the bovine alpha S1 casein gene promoter and the human growth hormone gene was microinjected into rat embryos. Transgenic lines that produced human growth hormone in their milk were established and used in this study. Immediately after birth, and without any hormone treatment, human growth hormone was found in the extracts of mammary glands from both male and female rats derived from the line secreting human growth hormone in their milk. The expression of the transgene in mammary glands of newborn rats was also detected by the presence of human growth hormone mRNA. Nontransgenic newborn rats did not express the human growth hormone gene in their mammary glands, while the mRNA for rat alpha casein, an endogenous milk protein, was found in all mammary glands from both transgenic and nontransgenic neonates. These results show that analyzing the expression of transgenes in the mammary glands of neonates is a valuable tool to select the desired transgenic animals and to shorten the selection schedules establishing the transgenic animals.