Proximal tubular epithelial cells possess a novel 42-kilodalton guanine nucleotide-binding regulatory protein

The proximal tubule of the kidney represents an important location where adenylate cyclase regulates salt and water transport; yet a detailed characterization of the distribution and classification of guanine nucleotide-binding protein (G protein) and adenylate cyclase is lacking. We used purified brush border (20-fold) and basolateral membranes (14-fold) to characterize parathyroid hormone- and G protein-regulated adenylate cyclase and G-protein distribution. Adenylate cyclase was predominantly localized to basolateral membranes, while the 46-kDa alpha subunit of the stimulatory G protein (Gs) was 2-fold higher in brush border membranes than in basolateral membranes. The alpha subunit of the inhibitory G protein (Gi; 41 kDa) was equally distributed on immunoblotting but was 2-fold higher in brush border membranes than in basolateral membranes on radiolabeling with pertussis toxin. A 42-kDa cholera toxin substrate that cross-reacted with antisera to the common alpha subunit of G proteins and to Gs on immunoblotting and that was not immunoprecipitated with two Gi antisera was the most abundant alpha subunit and comprised approximately 1% of the total membrane proteins. These observations suggest that G proteins are important regulators of proximal tubular transport independent of adenylate cyclase.

Increased antibody responses to human papillomavirus type 16 L1 protein expressed by recombinant vaccinia virus lacking serine protease inhibitor genes

The L1 gene of human papillomavirus type 16 (HPV-16) driven by the vaccinia virus major late 4b gene promoter has been inserted into three different sites of the vaccinia virus genome. Insertion into the thymidine kinase (TK) gene was achieved by selection of TK- mutants in BUdR on TK- cells. Insertion into two vaccinia virus serine protease inhibitor (serpin) genes was achieved by co-insertion of the Escherichia coli xanthine guanine phosphoribosyltransferase gene linked to the vaccinia virus 7.5K promoter and selection of mycophenolic acid-resistant recombinant viruses. Each recombinant virus expressed a 57K L1 protein at similar levels and with similar kinetics. However, immunization of mice with these recombinant viruses induced different levels of antibody to the L1 protein. Viruses lacking serpin genes B13R and B24R induced significantly higher antibody levels than did viruses lacking the TK gene. The presence of functional B13R and B24R gene products is therefore somehow immunosuppressive at least for antibody responses to the L1 protein of HPV-16.

[Effects of processing on volatile oil constituents in nutmeg and on the contents of myristicin]

This paper reports a GC analysis of the volatile oil contained in the nutmeg (Semen Myristicae) prepared by simmering wrapped in flour in hot purified talc, scalding in hot purified talc and stir-frying in smoking wheat bran. The experimental results showed that before and after processing the volatile oil compounds in nutmeg are the same and during processing no known compounds disappeared. The contents of the main volatile oil compounds in nutmeg changed, however, before and after processing, including the amounts of myristicin, one of the toxic compounds in nutmeg. It is suggested that the amounts of myristicin could be decreased notably under certain processing conditions.

[Effects of processing methods on the amounts of volatile oil of nutmeg and on isolation and characterization of the volatile oil constituents]

In this paper, the authors investigated the effects of various processing methods, i.e., scalding in hot purified talc, simmering wrapped in flour in hot purified talc and stir-frying in smoking wheat bran, on nutmeg (Semen Myristicae) in terms of the quantities of the volatile oil. The experimental results revealed that the amounts of volatile oil contained in nutmeg vary remarkably with the lengths of cooking time and the fluctuation of temperature. Detected by GC-MS-computer, 32 compounds of nutmeg were characterized, and their contents were determined by GC respectively.

Identification of mutations in the COL4A5 collagen gene in Alport syndrome

X-linked Alport syndrome is a hereditary glomerulonephritis in which progressive loss of kidney function is often accompanied by progressive loss of hearing. Ultrastructural defects in glomerular basement membranes (GBM) of Alport syndrome patients implicate an altered structural protein as the cause of nephritis. The product of COL4A5, the alpha 5(IV) collagen chain, is a specific component of GBM within the kidney, and the gene maps to the same X chromosomal region as does Alport syndrome. Three structural aberrations were found in COL4A5, in intragenic deletion, a Pst I site variant, and an uncharacterized abnormality, which appear to cause nephritis and deafness, with allele-specific severity, in three Alport syndrome kindreds in Utah.

Purification and characterization of methylenetetrahydrofolate reductase from human cadaver liver

Methylenetetrahydrofolate reductase from human cadaver liver was purified to homogeneity. The purified enzyme had a molecular mass of 150 kDa. On SDS-polyacrylamide gel electrophoresis it was dissociated into a single fragment with a molecular mass of 39 kDa. In contrast, fresh lymphocyte enzyme extract showed a major band with a molecular mass of 75 kDa and a minor band of 39 kDa. Fresh liver enzyme was inhibited by S-adenosylmethionine while the purified enzyme from human cadaver liver was not inhibited. These observations suggest that human methylenetetrahydrofolate reductase is composed of two identical subunits of 75 kDa each but is cleaved into a major single band due to autolysis in cadaver liver. The purified cadaver enzyme was a FAD-specific protein. The pH optimum was 6.6 for methylenetetrahydrofolate-NADPH oxidoreductase, 6.5 for methyltetrahydrofolate-menadione oxidoreductase, and 7.2 for NADP-menadione oxidoreductase. The Km values of human liver methylenetetrahydrofolate reductase were 17 microns for NADPH and 38 microns for methyltetrahydrofolate in the reduction of menadione, and 12 microns for NADPH in the reduction of methylenetetrahydrofolate.

Iodinated contrast medium as an aid to gallstone dissolution with methyl tert-butyl ether: in vitro study

Methyl tert-butyl ether (MTBE) floats on bile, whereas gallstones sink. Therefore, stones and MTBE are separated by a layer of bile. This study investigates the effect of contrast medium on flotation of gallstones in bile and its role in stone and fragment dissolution with MTBE. Fresh human gallstones, both calcified and noncalcified, from different patients were tested in vitro for flotation in bile, with and without addition of contrast medium. All gallstones or fragments sank in bile before the introduction of contrast medium. Noncalcified stones floated when the contrast medium-bile volume ratio was 1:6 or more, while double this amount of contrast medium was required to float calcified stones. Fragments did dissolve somewhat in MTBE in the presence of bile alone, but when contrast medium was added, almost complete dissolution occurred. This is thought to be due to increased contact between the fragments and MTBE, both floating on the contrast medium-bile mixture. Contrast material may be a useful adjuvant in gallstone dissolution therapy with MTBE in vivo.

[Treatment of orthostatic dysregulation by the principle of bu-shen yi-qi]

Sixty cases of orthostatic dysregulation was randomly divided into treatment group (TG) and control group (CG), both 30 cases. Traditional Chinese medical herbs were used for TG under the principle of Bu-Shen Yi-Qi, and routine treatments such as oryzanol, vitamin B1 and B6 were applied to CG. After a curable stage of one month, the results showed that 16 of TG and 4 of CG were cured; 8 of TG and 6 of CG improved. The cure rate and the effective rate were significantly better in TG than in CG (P less than 0.01). 43 cases (71.7%) clinically expressed mild anemia. Before and after the treatment, the values of RBC, SI, Hb, SIBC, MCH in 20 cases of TG turned significantly better (P less than 0.01), but 17 cases of CG remained unchanged under the principle. The authors purposefully selected herbs that contain rich trace elements. For example, iron is an important element of Hb and zinc is an element in proteotic nucleicacidase. The quantity of zinc in body is related to many enzyme activities. Since these herbs could increase chronotropic effect of blood vessels and cure anemia, they could be used to cure patients with orthostatic dysregulation.

Inhibition of human immunodeficiency virus type 1 replication and cytopathicity by synthetic soluble catecholamine melanins in vitro

Synthetic soluble melanins were synthesized by spontaneous oxidation of L-dopamine, norepinephrine or 5-hydroxytryptamine (serotonin) in weak alkaline solution. These three melanins inhibited infection of human CD4+ lymphoblastoid cells (MT-2) by cell-free human immunodeficiency virus type 1 (HIV-1), without cell toxicity, at concentrations of 0.15-10 micrograms/ml. Also, syncytium formation and resulting cytopathic effects when uninfected cells were mixed with chronic HIV-1-infected cells were blocked by these melanins. Antisyncytial activity was greater when infected cells were preincubated with melanin than when uninfected cells were preincubated with melanin, thus suggesting that interaction of melanin with viral proteins is an important aspect of the antiviral mechanism. These results make synthetic soluble melanins interesting candidates for further study as possible anti-HIV-1 therapeutics.

[Analgesic and anti-inflammatory effects and toxicity of houjianxi]

It is effective for acute and chronic laryngopharyngitis clinically. Houjianxi can raise the pain thresholds during hot-plate test in mice, tail flick test in rats, and writhing test in mice with single dose ig 0.125 to 2.0 g/kg. Houjianxi can also inhibit the swelling of hind paw induced by sc 1% carrageenin 0.1 ml in rats as well as the increased vascular permeability induced by ip 0.7% HAC in mice. Toxic side effects were not observed for Houjianxi ig 48 g/kg x 3 within a day in mice and 1.8 g/kg daily for 90 d in rats.

Detection of human papillomavirus DNA in cytologic specimens derived from esophageal precancer lesions and cancer

A series of 80 esophageal cytologic specimens derived from the same number of patients with previously diagnosed squamous cell dysplasia of the esophagus were examined for the presence of human papillomavirus (HPV) infection by filter in situ hybridization (FISH), using a mixed DNA probe containing HPV types 11, 16, and 18. All the patients came from an area at high risk for esophageal cancer in China. A total of 53 cases (66.3%) were demonstrated as HPV-DNA-positive. HPV DNA was detected in 22.2% (2 of 9) of the patients without cytologic atypia, in 50% (3 of 6) with mild dysplasia, in 80.6% (25 of 31) with moderate dysplasia, in 67.9% (19 of 28) with severe dysplasia, and in 66.7% (4 of 6) with an invasive squamous cell carcinoma. The present results confirm the recent findings on HPV involvement in esophageal squamous cell lesions. They support the hypothesis that HPV is a possible etiologic agent in esophageal carcinogenesis, most probably acting synergistically with physical, chemical, and/or nutritional factors that have previously been related with this malignancy in the high-risk areas of China.

Radiation survival properties of cultured human gastric adenocarcinoma cells and the effect of AT-1727

Tumor cells (SGC-7901) obtained from a human gastric adenocarcinoma have been examined with regard to their intrinsic sensitivity to gamma-irradiation and as to how this intrinsic sensitivity might be altered by growth in a synthesized agent AT-1727 (N4-morpholino-methyl-3,5-dioxopiperazynyl-1,2 ethanl). Clonogenic survival was measured via colony formation assays and fitted to single-hit-multitarget formula. Exponentially growing cells exhibited the mean of survival parameters: D0 = 0.86 + 0.04 Gy; n = 7.03 + 2.3; Dq = 1.63 + 0.23 Gy and SF2 (surviving fraction of conventional daily clinical dose of 2 Gy) = 45-50%. Split-dose survival assays and delayed plating methods were used to exploit the capacity of sublethal damage repair of this cell line studied demonstrating the reappearance of initial shoulder on the survival curve and an increased survival. Alteration of radiosensitivity of SGC cells by AT-1727 was shown when cultures were incubated in a medium with the drug for a 6 hr interval between split dose irradiation, indicating the inhibition of sublethal damage repair. The radioresistance of hypoxic SGC cells was decreased when pre-treatment with AT-1727 was given 2 hr before irradiation, and the decrease of surviving fraction was drug-dose dependent. A maximum enhanced effect was obtained when 0.15 mM of AT-1727 was used, reaching an ER of 1.24. Inhibition of sublethal damage repair and action as a hypoxic radiosensitizer were considered to be two parts of the mechanism of AT-1727 in modification of radiation effects.

DNA flow cytometric analysis of human nasopharyngeal carcinoma in nude mice

The tissue from a patient with nasopharyngeal carcinoma has been transferred to nude mice (BALB/c), and has successfully been growing through twenty passages. The tumors in the nude mice and primary human tumor have been examined for the cellular DNA content by FCM and also conventional pathological examination, chromosome analysis, and EBV test. The tumor take rate varied markedly in different passages with a mean value of approximately 70%, and showing a tendency to increase. The tumor doubling time within 6-12 weeks after transplantation of six tumors in 18 and 20 passages were 14.8 and 9.3 days respectively. However, the tumor volume at 12 weeks varied significantly, ranging from 438 to 1998 mm3. By FCM, it has been found that the values of DNA index were about the same in both primary tumor and the tumors in nude mice. The distribution of various phase cells in cell cycle was also about the same in both. In conclusion, the application of FCM to examine the cellular DNA content of the tumor in nude mice is a rapid and sensitive method, useful in the investigation on the stability of biological characteristics of human NPC in nude mice and in further studies on the effects by various therapeutic methods.