Interaction of heptanol and pressure on sodium and chloride transport by toad skin

We examined the interaction of heptanol and hydrostatic pressure on Na+ and Cl- transport in isolated toad skin. In the presence of Cl-, heptanol decreased short-circuit current (Isc) and total transepithelial resistance (Rt). However, in the absence of Cl- in the mucosal bath, heptanol increased Rt, although it retained the same inhibitory effect on Isc. When transepithelial active Na+ transport was blocked by amiloride, heptanol had no effect on Isc whether or not Cl- was present, whereas it decreased the shunt resistance (Rs) only in the presence of Cl- in the mucosal bath. Moreover, this effect of heptanol on Rs was significantly smaller in the presence of diphenylamine-2-carboxylate (DPC), a known Cl- channel blocker. Pressure also decreased Isc through inhibition of active Na+ transport, but it increased Rs. When heptanol and pressure were applied together, their inhibitory effects on Isc were additive, but their effects on Rs were antagonistic. Furthermore, when a transepithelial Cl- current was produced by reducing the Cl- concentration of the serosal bath, heptanol stimulated this current, which was reversibly inhibited by pressure or DPC addition to the mucosal bath. When the heptanol-stimulated Cl- current was first inhibited by pressure, subsequent DPC addition had less or no effect. These results suggest that one site of an antagonistic interaction of heptanol and pressure in toad skin is an apical membrane Cl- conductance.

Radiograph ordering: agreement between the triage nurse and the physician in a pediatric emergency department

We hypothesized that the triage nurse in a busy pediatric emergency department (ED) could accurately order radiographs, ultimately reducing patient waiting time. Protocols utilized to reduce patient waiting time are of importance in busy emergency departments. All patients registering at the ED of the Children's Hospital in a one-week period were entered into the study. The triage nurse documented whether they would send the patient for a radiograph, if allowed to, and were asked to designate a specific radiograph. The radiographs that were actually ordered by the physicians were subsequently obtained from radiology records. Data were analyzed for agreement beyond chance (kappa), positive (PPV) and negative predictive values. The results showed excellent agreement for extremity radiographs and poor agreement for nonextremity radiographs.

[Studies on pickled vegetables and cause of esophageal cancer in Linxian. I. Experiments on carcinogenicity of pickled vegetables]

Pickled vegetables are a traditional daily food served in several parts of China where esophageal cancer is prevalent, and the mortality rate due to this cancer appears to be correlated with the time span of consumption and the amount consumed. For the present study epithelial hyperplasia and papillomas of the esophagus and forestomach were induced in mice and rats following administration of condensed juice from or extract of pickled vegetables from Linxian County, Henan Province. Only one case of forestomach carcinoma was observed in a rat subsequent to prolonged treatment with pickled extract, indicating that carcinogens in pickled vegetables alone are probably incapable of inducing carcinogenesis.

Evidence for identifying fatty acids in rat liver glutathione S-transferase and its possible involvement in the secondary structure

A rat liver glutathione S-transferase isozyme (GST 3-3) has been purified to apparent electrophoretic homogeneity by procedures including Sephadex G-100, S-hexylglutathione-linked Sepharose, and CM-cellulose column chromatographies. The present study provides evidence for the existence of endogenous fatty acids in the purified GST 3-3 by gas-liquid chromatographic and mass-spectrometric analyses. The liver GST isozyme associated long chain fatty acids such as 14:0, 16:0, 18:0, and 18:1 and the molar ratio of fatty acids to the protein was estimated to be around 3.2. When the enzyme preparation was freed of fatty acids by a mild delipidization technique using Lipidex, the GST activity was significantly decreased. Computer analysis of the circular dichroism spectra revealed that rat liver GST 3-3 contained approximately 49% alpha-helix and 24% random coil. By delipidizing, the enzyme's alpha-helix was decreased to 4% and the random coil was in turn increased to 62%. The enzymatic and structural properties of the delipidized enzyme, however, could be restored to nearly the original levels by recombining with the fatty acids. These findings suggest that weakly bound fatty acids are responsible for the functional capacity of the GST by virtue of changing the protein conformation.

Apical membrane Cl- channels in airway epithelia: anion selectivity and effect of an inhibitor

Previous work has investigated the anion selectivity of transepithelial Cl- secretion by airway epithelia and its inhibition by the Cl(-)-channel blocker 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB). Here we report the anion selectivity of the apical membrane and of the outwardly rectifying Cl- channel and the effect of NPPB on the Cl- channel. The anion selectivity sequence of the apical membrane determined with conventional microelectrodes in the native epithelium was SCN- greater than I- greater than Br- greater than NO3- approximately Cl- much greater than SO(4)2- approximately gluconate-. This contrasts with the observation that Cl- and Br- support transepithelial secretion but that I- does not. Thus the anion selectivity of transepithelial transport is determined by the basolateral membrane Cl- entry step. The anion selectivity of the outwardly rectifying Cl- channel studied in excised patches was the same as that of the apical membrane. We also found that NPPB reversibly blocked the outwardly rectifying Cl- channel from both the internal and external surfaces of the patch. NPPB, 10 microM, completely blocked the channel; lower concentrations caused a decrease in the probability of finding the channel in the open state. NPPB also caused the appearance of a subconductance state of the channel, an occurrence which is rarely observed in the absence of NPPB. These data provide further support for the conclusion that the outwardly rectifying Cl- channel is responsible for Cl- exit from the cell across the apical membrane.

[The significance of retinal nerve fiber layer examination in the diagnosis of glaucoma]

To evaluate the significance of nerve fiber layer (NFL) changes in the diagnosis of glaucoma, the authors examined 197 cases (347 eyes) of normal subjects, primary open angle glaucoma (POAG), low tension glaucoma (LTG) and suspects of these two types of glaucoma. The sensitivity of NFL atrophy to glaucoma was high: in POAG eyes with field loss, 88.9% (64/72) had NFL atrophy. In 123 normal eyes, NFL atrophy was found in only one eye, the specificity of NFL atrophy being 99.2%. All LTG patients and suspects of LTG had NFL atrophy. In the fellow eyes of POAG with normal fields and eyes of POAG suspects, NFL defects occurred in 53.8% (7/13) and 20.6% (15/73) respectively. The examination of NFL is a simple procedure; the nerve fibers themselves are directly observed rather than their function. When half of the thickness of NFL is lost, it Will be manifested clinically. With its high sensitivity and specificity, NFL atrophy can be regarded as an important indicator in the diagnosis of glaucoma.

Absence of diuresis during a 7-day saturation dive at 2.5 ATA N2-O2

Three male divers were studied for 2 days during each of the predive and postdive 1 ATA air control periods and for 7 days at 2.5 ATA (2.3 ATA N2 and 0.2 ATA O2). The chamber temperature was always maintained at a comfort level. Average urine flow remained at 1500 ml.day-1 during both predive and 2.5 ATA periods; urine osmolality also remained constant at around 700 mOSM/kg. On the other hand, daily excretion of Na increased significantly from 139 mEq during the predive period to 178 mEq at 2.5 ATA (P less than 0.05) but returned to the predive level during the postdive period. In contrast, daily K excretion decreased progressively with a significant decrease during the postdive period (P less than 0.05). Plasma osmolality, Na, and K remained unchanged, whereas a 6% reduction of total protein concentration at 2.5 ATA (P less than 0.05) was observed. A quantitatively similar decrease (8%) was observed for hematocrit during the 2.5 ATA period, which did not recover at postdive. These changes were accompanied by a significant increase in urinary excretion of antidiuretic hormone (P less than 0.05) and by decreases in both plasma renin and aldosterone (P less than 0.05) level and urinary excretion of aldosterone (P less than 0.05). Plasma atrial natriuretic factor remained unchanged throughout the entire dive period.

[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.

Urinary riboflavin excretion after a load test in rural China as a measure of possible riboflavin deficiency

Urinary excretion of riboflavin was measured in 3318 adults 4 h after an oral dose of riboflavin. Male and female subjects aged 35-64 years were selected from 65 mostly rural counties located in 24 provinces of China. Counties were selected to represent a range of seven of the most prevalent cancer mortality rates in China and within counties households were selected at random. Urinary riboflavin excretion levels after a load test, erythrocyte glutathione reductase activity coefficients (EGR-AC), dietary riboflavin intakes, and a large number of other biochemical, dietary, and environmental parameters were measured. Mean dietary intake of riboflavin was 75 per cent of the Chinese recommended dietary allowances (CRDA). Mean meat intake per reference man was very low (26.4 +/- 23.7 g/d) in comparison to Western standards and milk was not consumed at all in most counties. Mean EGR activity coefficients measured on 'blood pools' for both males (1.47 +/- 0.14) and females (1.48 +/- 0.16) indicated that more than two-thirds of the population surveyed was in the medium or high risk category of riboflavin deficiency. Using current reference standards of less than 1.4 mg for 4-h urinary excretion of riboflavin after a 5 mg load, more than 70 per cent of the individuals examined exhibited low levels usually associated with high risk of riboflavin deficiency. In view of the lack of specificity for clinical indications of riboflavin deficiency and the tentative validity of the present CRDA, the interpretation of the data is problematic. We suggest that the present CRDA for this vitamin is set too high and requires critical review and possibly some revision.

Calcium-dependent regulation of airway epithelial chloride channels

To determine how cell calcium ([Ca2+]c) regulates apical Cl- channels, we measured the rate of 125-Iodide (125I-) efflux to assay Cl- channel activity in intact cells and examined cell-free membrane patches from cultured canine tracheal epithelial cells. The Ca2+ elevating agonist bradykinin and the calcium ionophore A23187 increased 125I- efflux. This response did not require prostaglandin production. Under several conditions, changes in [Ca2+]c were temporally dissociated from changes in channel activation: a transient increase in [Ca2+]c caused a prolonged stimulation of 125I- efflux. Neither Cl- channel activation nor open-channel probability was affected by varying internal [Ca2+] in excised membrane patches. Adenosine 3',5'-cyclic monophosphate (cAMP)- and Ca2(+)-dependent channel activation may be independent: cAMP-stimulated 125I- efflux did not require an increase in [Ca2+]c, Ca2(+)-stimulated efflux did not require an increase in cAMP, and simultaneous addition of A23187 and isoproterenol produced additive effects on 125I- efflux. The data suggest that an increase in [Ca2+]c activates Cl- channels, however, the effect of Ca2+ appears to be indirect, not involving a ligand-type interaction with the channel.

[A report on systolic hypertension in 1682 elderly peasants in Chengdu area]

Blood pressures of 1682 elderly peasants in Chengdu were measured at cluster random. The prevalence rate of hypertension was 15.7% and higher than that in early elderly (P less than 0.01). The rate of systolic hypertension was 75.4% and increased with the increase of age. The rate in females was higher than that in males (P less than 0.01). Electrocardiograms of these hypertension persons were analyzed with Minnesota code, and the incidence rates of two types were not statistically significant. These results show that the change of heart function resulted from hypertension is related with the rise of systolic pressure as well the rise of diastolic pressure.

Obstructive jaundice promotes bacterial translocation from the gut

Experiments were performed to determine if obstructive jaundice promotes the translocation of bacteria from the gastrointestinal tract to visceral organs. Three groups of mice were studied: control (n = 20), sham ligated (n = 28), and bile duct ligated (n = 33). The sham-ligated group underwent laparotomy and manipulation of the portal region, whereas the ligated group had their common bile ducts ligated. Seven days later, the mice were killed, their organs cultured, and the gastrointestinal tract examined histologically. The bilirubin levels of the ligated group (18.7 mg/dL) were elevated compared with the other groups (0.5 mg/dL) (p less than 0.05). The incidence of bacterial translocation was higher in the ligated (33%) than in the control (5%) or sham-ligated (7%) groups (p less than 0.05). Since bile is important in binding endotoxin and maintaining a normal intestinal microflora, cecal bacterial populations were quantitated. The cecal levels of gram-negative, enteric bacilli were 100-fold higher in the bile duct-ligated mice in which bacterial translocation occurred (p less than 0.05), indicating that intestinal bacterial overgrowth was a major factor responsible for bacterial translocation. The mucosal appearance of the intestines from the control and sham-ligated groups was normal. In contrast, subepithelial edema involving the ileal villi was present in the ligated group. In conclusion, the absence of bile within the gastrointestinal tract allows intestinal overgrowth with enteric bacilli and the combination of bacterial overgrowth and mucosal injury appears to promote bacterial translocation.

Increased morbidity in surgical patients undergoing secondary (incidental) cholecystectomy

Using computerized hospital discharge abstracts for all Vermont residents hospitalized during 1983 and 1984, we examined the question of whether increased morbidity occurs in patients undergoing secondary (incidental) cholecystectomy. Among a cohort of 4183 patients undergoing a primary surgical procedure in which secondary cholecystectomy might have been considered. 69 patients had a secondary cholecystectomy. The surgical wound infection rate was 8.7% in the secondary cholecystectomy group compared to 2.4% in the rest of the cohort (relative risk, 3.7, 95% C.I. 1.7, 8.1). Other postoperative complications occurred in 10.1% of those undergoing secondary cholecystectomy compared to 4.1% in those who did not (relative risk, 2.5, 95% C.I. 1.2, 5.1). The adjusted relative risk for wound infection was 3.3 (95% C.I. 1.4,8.0) and for other surgical complications was 1.7 (95% C.I. 0.8, 3.8). Postoperative length of hospital stay was longer for the secondary cholecystectomy group (mean, 13.8 days) than in the comparison group (mean 8.9 days, p = 0.001). These data suggest that patients undergoing a secondary cholecystectomy may have an increased risk of surgical wound infection and possibly other surgical complications.

Activation of normal and cystic fibrosis Cl- channels by voltage, temperature, and trypsin

In cystic fibrosis (CF) phosphorylation-dependent activation of outwardly rectifying apical membrane Cl- channels is defective. To further understand regulation of this channel we examined several other mechanisms of channel activation in normal and CF cells. Previous studies have shown that strong membrane depolarization can activate channels in excised cell-free membrane patches. Here we show that such activation is dependent on both the absolute membrane voltage and the duration of depolarization. Moreover, activation was reversible by membrane hyperpolarization. In some cases, excising patches of membrane from the cell caused channel activation, even in the absence of depolarization. However, the frequency of channel activation with patch excision increased when bath temperature was increased from 23 to 37 degrees C. Although the channel remained in the activated state when temperature was reduced to 23 degrees C, subsequent hyperpolarization inactivated the channel. In cell-attached patches, neither depolarization nor increasing bath temperature to 37 degrees C activated channels, suggesting that neither is physiologically important in regulation of the channel. Thus changes in membrane voltage and bath temperature appear to cause a nonenzymatic change in the channel's conformation; the interactions between voltage and temperature suggest that they may affect the same process. To determine if a proteolytic alteration of the channel could also cause activation, we added trypsin to the cytosolic surface of excised membrane patches. Trypsin activated channels, which could not then be inactivated by either hyperpolarization or phosphorylation with PKC, suggesting that trypsin removed or altered a region of the channel involved in inactivation. All of these interventions activated Cl- channels from both normal and CF cells. Thus many aspects of Cl- channel activation are normal in CF; only phosphorylation-dependent activation is defective.

Identification and regulation of whole-cell chloride currents in airway epithelium

We used the whole-cell patch-clamp technique to study membrane currents in human airway epithelial cells. The conductive properties, as described by the instantaneous current-voltage relationship, rectified in the outward direction when bathed in symmetrical CsCl solutions. In the presence of Cl concentration gradients, currents reversed near ECl and were not altered significantly by cations. Agents that inhibit the apical membrane Cl conductance inhibited Cl currents. These conductive properties are similar to the conductive properties of the apical membrane Cl channel studied with the single-channel patch-clamp technique. The results suggest that the outwardly rectifying Cl channel is the predominant Cl-conductive pathway in the cell membrane. The steady-state and non-steady-state kinetics indicate that current flows through ion channels that are open at hyperpolarizing voltages and close with depolarization. These Cl currents were regulated by the cAMP-dependent protein kinase: when the catalytic subunit of cAMP-dependent protein kinase was included in the pipette solution, Cl channel current more than doubled. We also found that reducing extracellular osmolarity by 30% increased Cl current, suggesting that cell-swelling stimulated Cl current. Studies of transepithelial Cl transport in cell monolayers suggest that a reduction in solution osmolarity activates the apical Cl channel: reducing extracellular osmolarity stimulated a short-circuit current that was inhibited by Cl-free solution, by mucosal addition of a Cl channel antagonist, and by submucosal addition of a loop diuretic. These results suggest that apical membrane Cl channels may be regulated by cell volume and by the cAMP-dependent protein kinase.

Phosphorylation-dependent regulation of apical membrane chloride channels in normal and cystic fibrosis airway epithelium

The observations described herein allow us to make several inferences about PKC and regulation of normal and CF Cl- channels. FIGURE 5 shows a model that summarizes these observations. In this model, for the sake of clarity, we refer to the channel as a single entity, but note that it may consist of multiple subunits and associated proteins. FIGURE 5A shows the channel in an inactivated state following excision from the cell. The channel can be activated by strong membrane depolarization, via an unknown mechanism, or by phosphorylation with PKA or PKC at a low [Ca2+] We speculate that PKA and PKC may phosphorylate and activate the channel at the same site, or region of the channel, because phosphorylation-dependent activation by both is defective in CF. This result suggests that the CF defect might lie in a defective phosphorylation site on the channel, or associated protein, or in the mechanism that converts phosphorylation into a change in channel conformation, such as activation. Activated channels can be inactivated by PKC at a high [Ca2+]. At high [Ca2+], PKC maintains the channel in an inactivated state and it inactivates channels that have been activated by PKC at low [Ca2+], by depolarization, or by PKA. Both activation and inactivation appear to result from phosphorylation; neither can be explained by down-regulation of the channel. There are several possible ways to explain the two opposite effects of PKC on the Cl- channel: different responses may be due to an effect of Ca2+ on the channel, on PKC, or on the interaction between the two.(ABSTRACT TRUNCATED AT 250 WORDS)

[Protective effect of extracts from Aloe vera L. var. chinensis (Haw.) Berg. on experimental hepatic lesions and a primary clinical study on the injection of in patients with hepatitis]

The injection(10-15 ml/kg/d, ip x 4), total glycoside (125-225 mg/kg/d, ip x (3-4); 600 mg/kg/d, ig x 3) and crystal III (120 mg/kg/d, ip x 4) of Aloe vera var. chinensis were found to be effective in lowering the elevated sGPT induced by CCl4, thioacetamide and D-aminogalactose in mice or rats. It was also observed that these agents could protect hepatic cells from the CCl4-induced injury. When dogs were given in with Aloe injection of 0.1 ml/kg/d x 180, no toxicity was noted. The total effective sGPT-lowering rate of Aloe injection on 38 patients of chronic hepatitis with positive HBsAg was 86.8%.

[Study on the biological nature of ginseng pearl knot]

Pearl knots of the root system of cultivated ginseng in different ages and different development stages were studied and compared with wild ginseng. It has been found that the biological nature of pearl knots is the foundation of seasonal absorbing root of ginseng. It is pointed out that to remove the cold-proof matter later and keep suitable soil water in spring are important to prevent cold injury and promote growth of root system of ginseng. Key words ginseng; pearl knot; seasonal absorbing root

Effects of protein malnutrition and endotoxin on the intestinal mucosal barrier to the translocation of indigenous flora in mice

Since protein malnourished or endotoxemic patients are at increased risk of developing nosocomial infections with enteric organisms, we investigated the effects of these risk factors alone and in combination on the intestinal mucosal barrier to bacteria. Protein malnutrition resulted in severe ileal atrophy that was directly related to the length of time the mice were protein malnourished. Although protein malnutrition did not promote bacterial translocation from the gut to systemic organs, the protein-malnourished mice were more susceptible to endotoxin-induced bacterial translocation than normally nourished mice (p less than 0.01). Since the gross epithelial damage documented after endotoxin administration in normally nourished mice was diminished after protein malnutrition, there was no correlation between the gross appearance of the epithelial mucosal barrier and the extent of endotoxin-induced bacterial translocation. These results suggest that the synergistic effect of endotoxin plus protein malnutrition on bacterial translocation is not primarily related to failure of the gut mucosal barrier. Nonetheless, it appears that protein-malnourished mice are less able to clear translocating bacteria than normally nourished mice.

NBP, a protein that specifically binds an enhancer of immunoglobulin gene rearrangement: purification and characterization

Immunoglobulin and T-cell receptor (TCR) genes are encoded in discrete germ line DNA segments that are joined by site-specific recombination during lymphocyte development. These DNA rearrangements are mediated by conserved heptamer and nonamer DNA sequence elements that lie near the sites of recombination. In this paper we show that the nonamer element coincides with the recognition site for a specific DNA-binding protein: mutations within the nonamer sequence, but not outside of it, decrease affinity for the binding protein by 300- to 1000-fold. Deletion of the binding site for the protein results in at least a 50-fold decrease in recombination frequency in vivo. By a combination of conventional and recognition site affinity chromatography, we have achieved greater than 20,000-fold purification of the protein from calf thymus, with an overall yield of 22%. The purified protein, which we now call nonamer-binding protein (NBP), has an apparent molecular weight of 63,000 and a frictional ratio of 1.27, suggesting that it exists as a globular monomer in 0.5 M NaCl. Our observations suggest that NBP is a component of the recombinational apparatus.

Thyroid autoimmunity in endemic goitre caused by excessive iodine intake

The pathophysiology of endemic goitre caused by excessive iodine intake is not well defined. By interacting with the immune system, iodine excess may trigger the development of autoimmune thyroid disease such as lymphocytic Hashimoto's thyroiditis (LT). In an attempt to examine this further, we compared the presence of thyroid autoantibodies in 29 goitrous children, from an iodine excess area, and in 26 healthy children, from an iodine sufficient area, of north central China. Serum was tested for antimicrosomal (MAb), anti-thyroglobulin (TgAb), second colloid antigen antibodies (CA2-Ab) and TSH binding inhibitory immunoglobulins (TBII). Affinity chromatographically purified IgG was tested for thyroid growth-stimulating activity (TGI) by two different methods: a sensitive cytochemical bioassay (CBA) using guinea-pig thyroid explants and a mitotic arrest assay (MAA) employing a continuous rat thyroid cell line (FRTL-5). We found no increased prevalence of LT in patients with endemic iodine goitre. The levels of MAb, TgAb and CA2-Ab did not differ significantly between the two groups of children. Further, TBII were not present in either group. Thyroid growth-stimulating immunoglobulins (TGI) were the major autoantibodies found in children with goitres caused by iodine excess. In the CBA, 12 of 20 (60%) goitrous children and 0 of 12 (0% P less than 0.05) healthy children were positive for TGI. Similar results were found in the MAA, and a good correlation between results of the CBA and MAA was found (P = 0.003). Maximal TGI activity in dose-response CBA showed a good relation with clinical goitre size (r = 0.63; P less than 0.05) indicating a possible pathophysiological role for these antibodies. We conclude that endemic iodine goitre is not associated with Hashimoto's lymphocytic thyroiditis. Nevertheless, autoimmune growth factors such as TGI may play a primary role in the pathogenesis of thyroid growth in this condition.

The efficacy of triclabendazole (Fasinex) against immature and adult Fasciola hepatica in experimentally infected cattle

Eighteen Chinese cattle were experimentally infected with metacercariae of Fasciola hepatica and randomly assigned to 6 groups. Five groups of cattle were treated with a single oral dose of triclabendazole at a dose rate of 12 mg kg-1. At necropsy, the reduction in fluke burden compared with the untreated group was 85, 99.6, 99.8, 100 and 100% for cattle treated 2, 6, 8, 12 and 16 weeks after infection, respectively. Data are also presented on body weight changes during the experimental period and on serum gamma-GT activity in cattle from selected groups. Triclabendazole is considered to be safer and more efficacious than currently available fasciolicides in China.

Effect of sodium on progesterone production in granulosa cells of rapidly growing chicken ovarian follicles

The importance of extracellular sodium (Nao+) in the progesterone production in hen granulosa cells from the first (F1), second (F2), and third (F3) largest preovulatory follicles was investigated in short term incubations. Progesterone synthesis in the absence or presence of the gonadotropin increased with increasing Nao+ concentration. Luteinizing hormone (LH) caused an additional and significant increase in steroidogenesis at every Nao+ concentration tested. However, no significant difference in the ED50 of Nao+ among F1, F2, and F3 cells was observed whether in the absence or the presence of the gonadotropin. Furthermore, although LH provoked steroidogenesis dose dependently in F1, F2, and F3 granulosa cells, no significant change in the ED50 of LH was observed among F1, F2, and F3 cells. The Na+/H+ exchange inhibitor, amiloride, attenuated both basal and LH-stimulated steroidogenesis in a concentration-dependent manner in the presence of Nao+. Amiloride was ineffective in the absence of Nao+. The present studies indicate the importance of Nao+ in the modulation of steroidogenesis in hen granulosa cells. Since steroidogenesis was suppressed by amiloride only in the presence of sodium, it is suggested that Nao+ is important for the maintenance/regulation of intracellular pH by an exchange with intracellular H+. Our studies also suggest that the sodium modulatory mechanism may not be a determinant in the differential progesterone production observed among the three largest preovulatory follicles.

Pediatric emergency medicine: a developing subspecialty

Questionnaires were sent to 245 North American institutions with pediatric residency programs. There was a 69% response rate. Pediatric emergency care is provided in three types of facilities: emergency departments in pediatric hospitals, separate pediatric emergency departments or combined pediatric and adult emergency departments, in multidisciplinary hospitals. There are at least 262 pediatricians practicing full-time pediatric emergency medicine. The majority work in pediatric emergency departments, an average of 30.7 clinical hours per week. There are 27 pediatric emergency medicine programs with 46 fellows in training and 117 full-time positions available for emergency pediatricians throughout North America. Varying qualifications for these positions include board eligibility in pediatrics, certification in Basic Life Support or Advanced Trauma Life Support, and a fellowship in pediatric emergency medicine. The demonstrated need for pediatricians, preferably trained in emergency care, clearly indicates that pediatric emergency medicine is a rapidly developing subspecialty of Pediatrics that will be an attractive career choice for future pediatricians.

Regulation of chloride channels by protein kinase C in normal and cystic fibrosis airway epithelia

Apical membrane chloride channels control chloride secretion by airway epithelial cells. Defective regulation of these channels is a prominent characteristic of cystic fibrosis. In normal intact cells, activation of protein kinase C (PKC) by phorbol ester either stimulated or inhibited chloride secretion, depending on the physiological status of the cell. In cell-free membrane patches, PKC also had a dual effect: at a high calcium concentration, PKC inactivated chloride channels; at a low calcium concentration, PKC activated chloride channels. In cystic fibrosis cells, PKC-dependent channel inactivation was normal, but activation was defective. Thus it appears that PKC phosphorylates and regulates two different sites on the channel or on an associated membrane protein, one of which is defective in cystic fibrosis.

[Pharmacologic effects of an extract of Arillus longan (Lour.) Steud. and Gecko]

ALG is an extract from Arillus longan and Gecko. Our experiment has shown that ALG ig 20 ml/kg/d X 10 elevates significantly tolerance in mice under low and high temperatures and anoxia, and also increases the body-weight of normal mice, while ALG ig 15 ml/kg/d X 14 protects body-weight from decreasing in reserpinized mice. An increase in spleen-weight has also been observed in normal mice with ALG ig 20 ml/kg/d X 7, and ALG ig 15 ml/kg/d X 10 elevates the clearance rate of iv charcoal particles in normal mice.

Influence of A23187 and dibutyryl cyclic AMP on progestagen production by rat granulosa cells in vitro

The gonadotrophic regulation of progesterone production by rat granulosa cells was examined in a chemically-defined medium containing FSH, dibutyryl cyclic AMP [Bu)2cAMP) and the calcium ionophore, A23187. FSH and A23187 alone significantly enhanced the production of pregnenolone, progesterone and its metabolite, 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OH-P) from endogenous substrate(s). Stimulation of progesterone production by A23187 was accompanied by an increase in 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) but not 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) activity, as attested by enhancement of the metabolism of exogenous pregnenolone to progesterone but not of progesterone to 20 alpha-OH-P. In contrast, although (Bu)2cAMP increased pregnenolone and progesterone production and the metabolism of exogenous progesterone to 20 alpha-OH-P, it failed to stimulate the conversion of exogenous pregnenolone to progesterone. The increase in progesterone production and in the conversion of exogenous pregnenolone to progesterone by FSH and A23187 was concentration- and time-dependent. Whereas maximal stimulation of de-novo progesterone synthesis by FSH was evident by 6 h (earliest time examined), a significant increase in the conversion of exogenous pregnenolone to progesterone in the presence of FSH or the ionophore was not noted until 12 h of incubation. Although a small but significant increase in progesterone production was also noted as early as 6 h of incubation in the presence of the calcium ionophore, this was markedly smaller than that elicited by FSH. We conclude that the calcium ionophore A23187 and (Bu)2cAMP have similar as well as distinct effects on progesterone production in rat granulosa cells in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium-dependent regulation of steroidogenesis in rat granulosa cells: possible involvement of a Na+/H+ antiport

The possible role of Na+/H+ antiport in the gonadotropic regulation of steroidogenesis was examined in rat granulosa cells incubated for up to 6 h in a chemically defined medium in the absence or presence of Na+ (128 mM), gonadotropin (FSH or LH; 0-500 ng/ml), dibutyryl cyclic AMP [Bu)2cAMP; 2 mM) and amiloride (0-1 mM). Replacement of Na+ (Na+0) in the incubation medium with choline chloride resulted in a marked decrease in basal and LH-, FSH- and (Bu)2cAMP-stimulated progesterone and 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OH-P) synthesis in vitro. The Na+/H+ exchange inhibitor, amiloride significantly suppressed basal and hormone-stimulated progestin production dose-dependently in the presence of Na+0. However, it was without effect in Na+-deficient medium. The effect of the inhibitor on progestin production appeared to be directed at specific step(s) involved in the synthesis of pregnenolone, as concentrations of amiloride which inhibited progesterone production failed to influence the metabolism of exogenous pregnenolone to progestins. Cell viability and the incorporation of [3H]leucine into acid-precipitable material were not affected by amiloride. Our findings support the contention that extracellular sodium is important for steroidogenesis in rat granulosa cells. The inhibition by amilordie indicates an involvement of the Na+/H+ exchange in the regulation of this granulosa cell function.

Isolation of Chinese hamster ovary cell mutants deficient in excision repair and mitomycin C bioactivation

Mitomycin C (MMC), a bifunctional alkylating agent, requires metabolic reduction to become biologically active. We have identified a series of genetically related Chinese hamster ovary cell lines which span approximately three orders of magnitude in the concentration of MMC required for cell killing. Many mechanisms, including drug transport, drug activation, drug detoxification, and the elimination, or repair, of drug-induced lesions, may contribute to the level of drug resistance in cells. By exploring each of the above mechanisms in the various Chinese hamster ovary cell lines, we have been able to classify these cell lines into four categories. Proceeding from least resistant to most resistant to MMC, the cell lines are: (a) proficient in the bioreduction of MMC and deficient in DNA excision repair; (b) deficient in some aspects of MMC bioreduction and deficient in repair; (c) bioreduction and repair proficient; and (d) bioreduction deficient and repair proficient.

Qa-2 expression in the adult murine thymus. A unique marker for a mature thymic subset

The MHC Ag, Qa-2, is expressed on all peripheral T cells, a subset of bone marrow cells, and to a lesser extent on B cells. The Qa-2 Ag is also expressed on 5 to 6% of normal adult murine thymocytes. Through the use of flow cytometry, counterflow centrifugal elutriation and acridine orange staining, we have analyzed the cell surface phenotype, cell size, and cell cycle status of this thymic population. Our studies indicate that Qa-2+ thymocytes are large, non-mitotic, G1 cells which have the cell surface phenotype of CD5+, CD3+, J11dLO and lack receptors for peanut agglutinin. This population can be further subdivided into three categories; CD4+/CD8-, CD4-/CD8+, and CD4-/CD8-. These data indicate that Qa-2 surface expression can only be detected on thymocytes in the final stages of differentiation. The Qa-2 Ag can be used as a cell surface marker to identify a unique subset of mature thymocytes.

Qa-2 expression in the adult murine thymus. A unique marker for a mature thymic subset

The MHC Ag, Qa-2, is expressed on all peripheral T cells, a subset of bone marrow cells, and to a lesser extent on B cells. The Qa-2 Ag is also expressed on 5 to 6% of normal adult murine thymocytes. Through the use of flow cytometry, counterflow centrifugal elutriation and acridine orange staining, we have analyzed the cell surface phenotype, cell size, and cell cycle status of this thymic population. Our studies indicate that Qa-2+ thymocytes are large, non-mitotic, G1 cells which have the cell surface phenotype of CD5+, CD3+, J11dLO and lack receptors for peanut agglutinin. This population can be further subdivided into three categories; CD4+/CD8-, CD4-/CD8+, and CD4-/CD8-. These data indicate that Qa-2 surface expression can only be detected on thymocytes in the final stages of differentiation. The Qa-2 Ag can be used as a cell surface marker to identify a unique subset of mature thymocytes.

The efficacy of high-dose 4'epidoxorubicin in hepatocellular carcinoma

An open phase II study of high-dose 4'epidoxorubicin (90 mg/m2) was conducted in 33 patients with inoperable hepatocellular carcinoma. Three out of the 33 (9%) patients showed tumour response. The treatment was relatively well tolerated with a moderate degree of haematological toxicity and alopecia, and a mild degree of nausea and vomiting. The overall median survival was 72 days with a prolongation in the patients who showed some response.

Characterization of human tracheal epithelial cells transformed by an origin-defective simian virus 40

To facilitate understanding of the mechanisms underlying pulmonary diseases, including lung cancer and cystic fibrosis, we have transformed and characterized cultures of human tracheal epithelial cells. Cells were transfected by calcium phosphate precipitation with a plasmid containing a replication-defective simian virus 40 (SV40) genome. Colonies of cells with enhanced growth potential were isolated and analyzed for transformation- and epithelial-specific characteristics. Precrisis cells were observed to express the SV40 large tumor antigen, produce cytokeratins, have microvilli, and form tight junctions. After crisis, cells continued to express the SV40 large tumor antigen as well as epithelial-specific cytokeratins and to display the apical membrane microvilli. Apical membrane Cl channels were opened in postcrisis cells exposed to 50 microM forskolin. These channels showed electrical properties similar to those observed in primary cultures. The postcrisis cells have been in culture for greater than 250 generations and are potentially "immortal." In addition to providing a useful in vitro model for the study of ion transport by human airway epithelial cells, the cells can be used to examine stages of neoplastic progression.

Effect of calcium ionophore A23187 on pregnenolone metabolism to progesterone in rat granulosa cells

The effect of calcium ionophore A23187 on the metabolism of pregnenolone to progesterone was examined in rat granulosa cells during a 24-h culture period. Granulosa cells harvested from pregnant mare's serum gonadotropin treated immature rats were incubated in the presence and absence of the divalent cation ionophore A23187. The ionophore induced progesterone synthesis from both endogenous sterol substrate and exogenous pregnenolone in a time- and concentration-dependent manner. Pregnenolone metabolism was examined in the presence of aminoglutethimide phosphate, an inhibitor of endogenous pregnenolone production. Steroid secretion resulting from metabolism of endogenous substrate was more sensitive to A23187 in that a lower concentration of the ionophore was required to induce a significant increase than that noted for exogenous pregnenolone metabolism. In addition, progesterone production from endogenous sterol occurred 6 h earlier than the observed increase in the conversion of pregnenolone to progesterone. These results indicate that A23187 and therefore possibly enhanced calcium influx may play a significant role in the regulation of pregnenolone metabolism in granulosa cells depending on the duration of incubation. The earlier steroidogenic response from endogenous substrate may be a reflection of an acute effect of A23187 on certain steroidogenic steps proximal to pregnenolone production.

Hemorrhagic shock induces bacterial translocation from the gut

Sepsis and multiple organ failure are common after hemorrhagic shock. The goal of the current experiments was to determine whether hemorrhagic shock would promote the translocation of bacteria from the gut to visceral organs. Twenty-four hours after being subjected to sham shock, or 30, 60, or 90 minutes of shock (30 mm Hg), rats were sacrificed and their organs quantitatively cultured for translocating bacteria. There was a direct relationship between the duration of hemorrhagic shock and the 24-hour mortality rate (p = 0.02). Bacteria did not translocate from the gut in the sham-shock rats, but did translocate to the mesenteric lymph nodes, livers, and spleens of the rats subjected to hemorrhagic shock (p less than 0.01). Rats subjected to 90 minutes of shock shock exhibited a greater degree of bacterial translocation than rats receiving 30 or 60 minutes of shock (p less than 0.05). The most common translocating bacteria were Escherichia coli and Enterococcus. Hemorrhagic shock injured the gut mucosa and caused subepithelial edema and focal areas of necrosis. Thus hemorrhagic shock followed by reinfusion of shed blood disrupts the gut barrier and allows indigenous bacteria normally contained within the gut to cause systemic infections.

Microfilaments and FSH stimulation of rat granulosa cell steroidogenesis in vitro

The secretion of progesterone and 20 alpha-hydroxypregn-4-en-3-one (20 alpha-dihydroprogesterone) by granulosa cells from 30-day-old rats pretreated with PMSG (4 i.u.; i.p.) was significantly increased in a time- and concentration-dependent manner by FSH or cytochalasin B. Whereas FSH markedly stimulated progestagen secretion during 3 h of incubation, a significant enhancement of the steroidogenic response was not noted until 12 h of exposure to the inhibitor in vitro. Although cytochalasin B also enhanced the submaximal stimulation of progestagen production by FSH (15 ng/ml), it was ineffective in the presence of maximal stimulatory concentration of the gonadotrophin (150 ng/nl). With increasing concentrations of cytochalasin B, the ability of FSH to further stimulate progestagen secretion was progressively reduced. Granulosa cells cultured in medium alone contained a prominent cytoplasmic array of microfilaments which was markedly reduced by FSH or cytochalasin B. FSH and, to a greater extent, cytochalasin B elicited concentration-dependent reductions in the mean area occupied by the cells on the culture surface, the contour index (a size-independent representation of cell profile irregularity) and cell perimeter, indicating that the cells underwent less spreading and were more spherical and regular in outline in the presence of either agent. The FSH-induced reductions in the three shape-related parameters were augmented by cytochalasin B although the influence of the FSH on the mean area and perimeter was progressively reduced in the presence of higher concentrations of cytochalasin B.(ABSTRACT TRUNCATED AT 250 WORDS)

Gonadotropic regulation of prostaglandin production by ovarian follicular cells of the pig

Prepubertal gilts were treated with 750 IU pregnant mare's serum gonadotropin (PMSG) and 72 h later with 500 IU human chorionic gonadotropin (hCG) to induce follicular growth and ovulation. Dispersed granulosa cells (GC) and theca interna cells (TC) from follicles of gilts 72 h (GC-72 and TC-72, respectively) and 108 h (GC-108 and TC-108 h, respectively) after PMSG treatment were cultured for 0, 12, 24, and 36 h in medium with or without luteinizing hormone (LH), dibutyryl cyclic adenosine 3',5'-monophosphate [Bu)2cAMP), calcium ionophore (A23187), and/or arachidonic acid (AA), and the production of prostaglandin E2 (PGE) and prostaglandin F2 alpha (PGF) was measured by radioimmunoassay. TC-72 was the principal source of PGs 72 h after PMSG. At 108 h, the production of PGE and PGF by GC was increased 10- and 30-fold, respectively, whereas corresponding increases by TC were 2-fold. LH and A23187 significantly stimulated PGE and PGF production by both GC-72 and TC-72, but only thecal PG production was stimulated by (Bu)2cAMP. LH had minimal or no effect on PG production by GC-108 and TC-108, but A23187 (GC-108, TC-108) and (Bu)2cAMP (TC-108) were stimulatory. Basal PG production by GC-72, GC-108, and TC-108 was stimulated by AA. However, production by GC and TC cultured in medium containing AA and LH, A23187, or (Bu)2cAMP was not different from that produced by AA alone. These findings suggested that GC and TC can synthesize PGs in vitro, but AA availability is rate-limiting in GC. After exposure to hCG in vivo, the capacity of both cell types to produce PGs is increased but is limited by AA availability.(ABSTRACT TRUNCATED AT 250 WORDS)

Diethyl ether as a substrate for acetone/ethanol-inducible cytochrome P-450 and as an inducer for cytochrome(s) P-450

The ability of diethyl ether to serve as a substrate for microsomal and purified cytochrome P-450 (P-450) and as an inducer for rat hepatic microsomal monooxygenase activities was examined. Microsomal oxidation of ether to acetaldehyde, as monitored by high pressure liquid chromatography, was elevated 3- to 5-fold by treatment of rats with acetone or ethanol, 1.5- to 2-fold by treatment with ether, and only slightly by phenobarbital treatment. Ether also induced N-nitrosodimethylamine demethylase by up to 2-fold and 7-pentoxyresorufin dealkylation by up to 10-fold. These trends agreed with immunoblot experiments in which ether was a weak inducer of the P-450 isozyme IIE1 (encoded by the rat gene P450IIE1), but a stronger inducer of IIB1. A monoclonal antibody against IIE1 inhibited the deethylation by 78% in microsomes from acetone-treated rats and by 45% in controls. N-Nitrosodimethylamine, as well as common inhibitors of IIE1 such as hexane, benzene, pyrazole, and phenylethylamine, strongly inhibited ether deethylation. Using microsomes from acetone-induced rats, the apparent Km for deethylation was 13.4 +/- 2.4 microM and the Vmax was 8.2 +/- 0.2 (nmol of acetaldehyde/min/nmol of P-450). The Km for the controls was 71.3 +/- 9.5 microM. The rates of deethylation at 1 mM ether by purified, reconstituted IIE1 and IIB1 were 4.2 and 0.42 (nmol of acetaldehyde/min/nmol of P-450), respectively. Cytochrome b5 stimulated the rate due to IIE1 apparently by a decrease in the Km. These findings, along with previous work showing marked inhibition by ether of IIE1-dependent reactions, strongly support a major role for this isozyme in ether metabolism.

Cyclic AMP-dependent protein kinase opens chloride channels in normal but not cystic fibrosis airway epithelium

Chloride (Cl-) secretion by the airway epithelium regulates, in part, the quantity and composition of the respiratory tract fluid, thereby facilitating mucociliary clearance. The rate of Cl- secretion is controlled by apical membrane Cl- channels. Apical Cl- channels are opened and Cl- secretion is stimulated by a variety of hormones and neurotransmitters that increase intracellular levels of cyclic AMP (cAMP). In cystic fibrosis (CF), a common lethal genetic disease of Caucasians, airway, sweat-gland duct, secretory-coil and possibly other epithelia are anion impermeable. This abnormality may explain several of the clinical manifestations of the disease. The Cl- impermeability in CF-airway epithelia has been localized to the apical cell membrane, where regulation of Cl- channels is abnormal: hormonal secretagogues stimulate cAMP accumulation appropriately but Cl- channels fail to open. Here we report that the purified catalytic subunit of cAMP-dependent protein kinase plus ATP opens Cl- channels in excised, cell-free patches of membrane from normal cells, but fails to open Cl- channels in CF cells. These results indicate that in normal cells, the cAMP-dependent protein kinase phosphorylates the Cl- channel or an associated regulatory protein, causing the channel to open. The failure of CF Cl- channels to open suggests a defect either in the channel or in such an associated regulatory protein.