[Clinical features of non-cirrhotic portal hypertension in patients with common variable immunodeficiency]

We wished to summarize the clinical features of common variable immunodeficiency (CVID) complicated by non-cirrhotic portal hypertension (NCPH) and to deepen our understanding of it. The case data of CVID complicated with NCPH admitted to Peking Union Medical College Hospital from January 1983 to May 2021 were analyzed retrospectively to summarize their clinical characteristics. Six patients with CVID combined with NCPH (three of each sex; 16-45 years) were assessed. Four patients had portal hypertension. All patients had anemia, splenomegaly, a normal serum level of albumin and transaminases, and possibly increased levels of alkaline phosphatase and gamma-glutamyl transpeptidase. Two patients were diagnosed with esophagogastric fundic varices by gastroscopy. Two patients underwent splenectomy (which improved hematologic abnormalities partially). Four patients had autoimmune disease. Two cases were diagnosed with nodular regenerative hyperplasia (NRH) upon liver biopsy. Six patients were administered intravenous immunoglobulin-G (0.4-0.6 g/kg bodyweight) once every 3-4 weeks as basic therapy. Often, CVID complicated with NCPH has: (1) The manifestations of portal hypertension as the primary symptom. (2) Autoimmune-related manifestations. Imaging can provide important diagnostic clues. The etiology may be related to hepatic NRH and splenomegaly due to recurrent infections.

[Meta analysis of the prevalence and influencing factors of WMSDs among dentists in China]

Objective: To explore the relevant factors of work-related musculoskeletal disorders (WMSDs) among dentists through Meta analysis, providing a basis for the prevention and control of WMSDs among dentists. Methods: In April 2022, cross-sectional research literatures on the prevalence correlation of WMSDs among Chinese dentists were searched in databases such as China National Knowledge Infrastructure, Wanfang, VIP, PubMed, Web of Science, and Em Base database. The search was conducted from the establishment of the database until April 2022, literatures were selected using keywords such as musculoskeletal disorders and dentists. To extract gender, age, length of service, disease classification and other related influencing factors as indicator, and prevalence was selected as the outcome indicator. After evaluating the quality of the literatures, RevMan 5.3 software was used to calculate the combined RD (95%CI) values of the included literatures. Results: A total of 15 articles were included, with a total sample size of 3646 people. Meta analysis results showed that the prevalence of WMSDs among dentists in China was 80%, and the top three parts of the incidence rates were 65% of the waist, 58% of the neck, and 50% of the back. Gender, age, length of service, region and disease classification all increased the risk of WMSDs, and the combined effect size were 75%, 78%, 71%, 77% and 82% respectively (P<0.05) . Conclusion: The occurrence of WMSDs among dentists in China is related to multiple factors such as gender, age, length of service and disease classification. The above risk factors should be taken into account in the workplace and preventive measures should be actively implemented to prolong the working life of dentists.

[Effect of simulated occlusal force on periodontal ligament stem cells of the deciduous teeth at different stages of root absorption]

Objective: To explore the related mechanisms of biological root resorption in decidual teeth by studying the biological effect of simulated occlusal force on the periodontal ligament stem cells (PDLSC) at different stages of root absorption. Methods: According to the tooth type and root absorption degree, healthy retained deciduous incisors and healthy first premolars that needed to be removed for orthodontic treatment were collected and divided into three groups with six teeth in each group: the deciduous unabsorbed group (UN group), the absorbed group (R group) and the permanent teeth group (P group). PDLSC was isolated from periodontal ligament and cultured. PDLSC of three groups were loaded with dynamic pressure of 0-45, 0-90, 0-135, 0-180, 0-225 and 0-270 kPa, respectively. The proliferation ability was detected by cell counting kit-8 (CCK-8) technique on day 1 to day 7, respectively. The apoptosis levels of PDLSC after loading with dynamic pressure of 0-45, 0-90, 0-135, 0-180 and 0-225 kPa were observed by the flow cytometry. The changes of microfilaments were observed by fibrous actin (F-actin) staining after the cytokeleton was subjected to dynamic pressure of 0-90 kPa. Results: PDLSC of three groups exhibited various proliferation abilities to dynamic pressure. The A values in the UN group and R group were significantly higher than those in the P group and the difference was statistically significant (P<0.05). However, there was no significant difference between the UN group and the R group (P>0.05). The A values of PDLSC in UN group and R group under dynamic pressures of 0-45, 0-90, 0-135 and 0-180 kPa had no statistical significance compared with the control group unloading dynamic pressure (P>0.05). However, under 0-225 and 0-270 kPa dynamic pressures, the A values at the day 3 to day 7 were statistically significant (P<0.05). The A values of PDLSC in P group under 0-45, 0-90, 0-135, 0-180 and 0-225 kPa dynamic pressures for 1 to 7 days were no statistically significant difference compared with the control group (P>0.05). The A value in P group under the 0-270 kPa was statistically significant only on day 3 (1.386±0.131) and day 5 to day 7 (1.728±0.226, 2.029±0.168 and 2.263±0.210, respectively)(P<0.05). The result of apoptosis showed that the A values of PDLSC in UN group, R group and P group were significantly increased under 0-90, 0-135, 0-180 kPa and above dynamic pressures, respectively (P<0.05) compared with the control group unloading dynamic pressure. Under 0-90 kPa dynamic pressure, F-actin fluorescence staining samples in three groups all showed green filaments which were arranged along the long axis of the cells in the R group and the P group, while some fibers in the UN group were closely arranged and promoted stress fiber assembly. Conclusions: The biological characteristics of PDLSC at different root absorption stages were changed when they were stimulated by mechanical stress, and PDLSC of the deciduous teeth at the root unabsorption stage were more sensitive to mechanical stress stimulation.

Dispersion-managed technique in temporal-frequency measurement for MoTe2-based ultrafast laser

Ultrafast phenomena exist widely in modern scientific research. The time scale of ultrafast phenomena is mostly in the order of picosecond, femtosecond, or even attosecond. Nowadays, it is still a major challenge to study these nonrepetitive transient processes. Here, a temporal-frequency measurement based on a dispersion-managed technique has been proposed for an MoTe₂-based ultrafast laser. The temporal-frequency measurement comprises a laser diode, an optical switch, a section of tunable dispersion compensation fiber, and a three-port beam splitter. Resolution of the proposed measurement can be tuned in a wide range; further, the upper and lower resolution limits are numerically simulated. The proposed measurement is expected to be applied in ultrafast pulse detection due to its application in real-time measurement of ultrafast nonrepetitive signals.

[Clinical analysis of eosinophilic gastroenteritis in 71 children]

Objective: To summarize the clinical data including manifestations, diagnosis, treatment and prognosis of eosinophilic gastroenteritis (EGE) in children. Methods: A retrospective analysis was performed in 71 patients with pathologically proven EGE at Beijing Children's Hospital Affiliated to Capital Medical University from January 2008 to January 2017. Their clinical manifestations, laboratory and imaging examinations, endoscopic findings, histopathological examinations, and treatment were collected and analyzed. Results: Among 71 EGE cases, 47 (66%) cases were male and 24 (34%) cases were female, and the median age was 9.2 (0.2-16.5) years old. The main clinical manifestations included abdominal pain (76%, 54/71), vomiting (68%, 48/71), anorexia (54%, 38/71), weight loss (38%, 27/71), and diarrhea (37%, 26/71). There were 27 cases (38%) with a history of allergic diseases or family history. The median absolute value of eosinophil in peripheral blood of the 71 patients was 0.4 (0-36.8)×10(9)/L, and 27 cases (38%) showed an increase in eosinophil counts. Serum IgE was measured in 52 patients (104.3 (3.4- 3 000.0)×10(3) U/L), and 30 patients (58%) showed an increase in serum IgE. A large number of eosinophils ((41.0±8.5)/HP) were found in 3 patients' ascites. The endoscopic examination of upper gastrointestinal tract revealed hyperemic edema in 62 cases (87%), plaque in 44 cases (62%), erosion in 17 cases (24%) and ulceration in 16 cases (23%). Histopathologically, in 8 cases (11%) the disease involved both stomach and duodeneum, in 21 cases (30%) involved stomach only, and in 37 cases (52%) involved duodeneum only. In addition, in 6 cases (8%) the disease involved esophagus and in 10 cases (14%) involved colorectum. Microscopically, eosinophil counts averaged 67/HP, 33/HP, 40/HP and 38/HP in esophageal, gastric, duodenal and colorectal mucosa respectively. A total of 34 cases were treated with glucocorticoid, and all these patients had alleviation of symptoms, which occurred within 14.9 days on average, but EGE recurred in 11 cases (32%). Conclusions: The clinical symptoms and endoscopic findings of EGE are diverse and nonspecific. Histopathological examination of gastrointestinal mucosa is particularly important for the diagnosis. Glucocorticoid treatment is effective, but the patients with EGE are prone to relapse.

Discrete bisoliton fiber laser

Dissipative solitons, which result from the intricate balance between dispersion and nonlinearity as well as gain and loss, are of the fundamental scientific interest and numerous important applications. Here, we report a fiber laser that generates bisoliton – two consecutive dissipative solitons that preserve a fixed separation between them. Deviations from this separation result in its restoration. It is also found that these bisolitons have multiple discrete equilibrium distances with the quantized separations, as is confirmed by the theoretical analysis and the experimental observations. The main feature of our laser is the anomalous dispersion that is increased by an order of magnitude in comparison to previous studies. Then the spectral filtering effect plays a significant role in pulse-shaping. The proposed laser has the potential applications in optical communications and high-resolution optics for coding and transmission of information in higher-level modulation formats.

Graphene-clad microfibre saturable absorber for ultrafast fibre lasers

Graphene, whose absorbance is approximately independent of wavelength, allows broadband light–matter interactions with ultrafast responses. The interband optical absorption of graphene can be saturated readily under strong excitation, thereby enabling scientists to exploit the photonic properties of graphene to realize ultrafast lasers. The evanescent field interaction scheme of the propagating light with graphene covered on a D-shaped fibre or microfibre has been employed extensively because of the nonblocking configuration. Obviously, most of the fibre surface is unused in these techniques. Here, we exploit a graphene-clad microfibre (GCM) saturable absorber in a mode-locked fibre laser for the generation of ultrafast pulses. The proposed all-surface technique can guarantee a higher efficiency of light–graphene interactions than the aforementioned techniques. Our GCM-based saturable absorber can generate ultrafast optical pulses within 1.5 μm. This saturable absorber is compatible with current fibre lasers and has many merits such as low saturation intensities, ultrafast recovery times, and wide wavelength ranges. The proposed saturable absorber will pave the way for graphene-based wideband photonics.

Subcellular lipid droplet distribution in red and white muscles in the obese Zucker rat

AIMS/HYPOTHESIS

Little is known about the subcellular distribution of lipids in insulin-resistant skeletal muscle. However, it has recently been suggested that lipid accumulation in the subsarcolemmal region directly contributes to insulin resistance. Therefore we hypothesised that regional differences in lipid distribution in insulin-resistant muscle may be mediated by: (1) a reduction in fatty acid trafficking into mitochondria; and/or (2) a regional increase in the enzymes regulating lipid synthesis.

METHODS

Transmission electron microscopy was used to quantify lipid droplet and mitochondrial abundance in the subsarcolemmal and intermyofibrillar compartments in red and white muscles from lean and obese Zucker rats. To estimate rates of lipid trafficking into mitochondria, the metabolic fate of radiolabelled palmitate was determined. Key enzymes of triacylglycerol synthesis were also determined in each subcellular region.

RESULTS

Subsarcolemmal-compartmentalised lipids represented a small absolute fraction of the overall lipid content in muscle, as regardless of fibre composition (red/white) or phenotype (lean/obese), lipid droplets were more prevalent in the intermyofibrillar region, whereas insulin-resistant white muscles were devoid of subsarcolemmal-compartmentalised lipid droplets. While, in obese animals, lipid droplets accumulated in both subcellular regions, in red muscle of these animals lipids only appeared to be trafficked away from intermyofibrillar mitochondria, a process that cannot be explained by regional differences in the abundance of triacylglycerol esterification enzymes.

CONCLUSIONS/INTERPRETATION

Lipid accumulation in the subsarcolemmal region is not necessary for insulin resistance. In the intermyofibrillar compartment, the diversion of lipids away from mitochondria in insulin-resistant animals probably contributes to lipid accumulation in this subcellular area.

Antioxidant micronutrients improve intrinsic and UV-induced apoptosis of human lymphocytes particularly in elderly people

OBJECTIVE

Aging and oxidative stress may lead to enhanced cellular damage and programmed cell death. To study the association of intrinsic apoptosis with age and the effect of antioxidant supplementation on intrinsic and UV-induced apoptosis in children, young and elderly people.

METHODS

The study was a 2 months, double-blind, randomized trial. Three age groups were studied: children, young adults and elderly people. A total of 274 healthy subjects were allocated to a group supplemented with moderate amounts of retinol, β-carotene, α-tocopherol, ascorbic acid and selenium or placebo. Plasma oxidative stress parameters were detected and apoptosis of lymphocytes was evaluated with TUNEL staining.

RESULTS

At baseline, percentages of intrinsic apoptosis were 13.8% and 11.1% in elderly and young people, respectively, both significantly higher than children (6.3%). A decrease of 1.7% and 2.3% in intrinsic apoptosis of lymphocytes was found in the supplemented groups of young and elderly people compared with their control groups (all p values <0.001), but no significant decrease in children. Moreover, percentages UV-induced apoptosis significantly decreased by 1.4%, 1.9% and 3.1% in children, young and elderly people, respectively, compared with control groups after the trial. There were considerable increments in concentrations of plasma β-carotene, retinol, tocopherol, ascorbic acid and selenium in all three treated groups after the supplementation.

CONCLUSIONS

Young and elderly people have a higher intrinsic apoptosis than children, which was improved by antioxidant supplementation. UV-induced damage was attenuated by the supplementation in all three age groups.

Coordinately regulated expression of FAT/CD36 and FACS1 in rat skeletal muscle

Protein-mediated fatty acid uptake and intracellular fatty acid activation are key steps in fatty acid metabolism in muscle. We have examined (a) the abundance of fatty acid translocase (FAT/CD36) mRNA (a fatty acid transporter) and long-chain acyl CoA synthetase (FACS1) mRNA in metabolically heterogeneous muscles (soleus (SOL), red (RG) and white gastrocnemius (WG)), and (b) whether FAT/CD36 and FACS1 mRNAs were coordinately up-regulated in red (RTA) and white tibialis muscles (WTA) that had been chronically stimulated for varying periods of time (0.25, 1, 6 and 24 h/day) for 7 days. FAT/CD36 mRNA and FACS1 mRNA abundance were scaled with (a) the oxidative capacity of muscle (SOL > RG > WG) (p < 0.05), (b) the rates of fatty acid oxidation in red and white muscles, and (c) fatty acid uptake by sarcolemmal vesicles, derived from red and white muscles. In chronically stimulated muscles (RTA and WTA), FAT/CD36 mRNA and FACS1 mRNA were up-regulated in relation to the quantity of muscle contractile activity (p < 0.05). FAT/CD36 mRNA and FACS1 mRNA up-regulation was highly correlated (r = 0.98). The coordinated expression of FAT/CD36 and FACS is likely a functional adaptive response to facilitate a greater rate of fatty acid activation in response to a greater rate of fatty acid transport, either among different types of muscles or in muscles in which capacity for fatty acid metabolism has been enhanced.

Denervation provokes greater reductions in insulin-stimulated glucose transport in muscle than severe diabetes

We have examined the independent and combined effects of insulin insufficiency (streptozotocin (STZ)-induced diabetes, 85 mg/kg i.p.) and reduced muscle activity (denervation) (7 days) on basal, insulin-stimulated and contraction-stimulated glucose transport in rat muscles (soleus, red and white gastrocnemius). There were four treatments: control, denervated, diabetic, and denervated + diabetic muscles. Contraction-stimulated glucose transport was lowered (approximately 50%) (p < 0.05) to the same extent in all experimental groups. In contrast, there was a much smaller reduction insulin-stimulated glucose transport in muscles from diabetic animals (18-24% reduction, p < 0.05) than in denervated muscles (40-60% reduction, p < 0.05) and in denervated + diabetic muscles (40-60% reduction, p < 0.05). GLUT-4 mRNA reduction was greatest in denervated + diabetic muscles (approximately -75%, p < 0.05). GLUT-4 protein was decreased (p < 0.05) to a similar extent in all three experimental conditions (approximately -30-40%). In conclusion, (1) muscle inactivity (denervation) and STZ-induced diabetes had similar effects on reducing contraction-stimulated glucose transport, but (2) muscle inactivity (denervation), rather than severe diabetes, produced a 2-fold greater impairment in skeletal muscle insulin-stimulated glucose transport.

The transferrin receptor defines two distinct contraction-responsive GLUT4 vesicle populations in skeletal muscle

Insulin and contraction increase glucose transport in an additive fashion in skeletal muscle. However, it is still unclear whether they do so by inducing the recruitment of GLUT4 transporters from the same or distinct intracellular compartments to the plasma membrane and the T-tubules. Using the transferrin receptor as a recognized marker of recycling endosomes, we have examined whether insulin and/or contraction recruit GLUT4 from this pool to either the plasma membranes or T-tubules, isolated by subcellular fractionation of perfused hindlimb muscles. Either stimulus independently increased GLUT4 translocation from an intracellular fraction to both the plasma membrane and T-tubules. The combination of insulin and contraction induced a marked (approximately threefold) and almost fully additive increase in GLUT4 content, but only in the plasma membrane. Insulin did not stimulate transferrin receptor recruitment from the GLUT4-containing intracellular fraction to either the plasma membrane or the T-tubules. In contrast, contraction stimulated the recruitment of the transferrin receptor from the same GLUT4-containing intracellular fraction to the plasma membrane but not to the T-tubules. Contraction-induced recruitment of the transferrin receptor was also observed from immunopurified GLUT4 vesicles. It is concluded that muscle contraction stimulates translocation of GLUT4 from two distinct intracellular compartments: 1) a population of recycling endosomes that is selectively recruited to the plasma membrane and 2) from GLUT4 storage vesicles that are also insulin-responsive and recruited to both the plasma membrane and the T-tubules. The lack of additive translocation of GLUT4 to the T-tubules may be linked to the failure of GLUT4-containing recycling endosomes to be recruited to these structures.

GLUT-4 Deficiency and severe peripheral resistance to insulin in the teleost fish tilapia

Teleost fish, in general, are glucose intolerant; this trait has been attributed to piscine islets secreting insulin primary in response to amino acid secretogogues rather than glucose. However, pancreatic islet from the teleost fish tilapia, when transplanted into diabetic nude mice, were glucose responsive even though tilapia were severely glucose intolerant. This suggested a strong peripheral resistance to the glucostatic effects of insulin. Using Western blotting with polyclonal antibodies as well as Northern analysis for mRNA, tilapia tissues were found to be devoid of GLUT-4, the insulin-sensitive glucose transporter responsible for the hypoglycemic effect of insulin in mammals. The absence of GLUT-4 in peripheral tissues may explain why tilapia, and possibly other teleost fish, are severely glucose intolerant. This suggests that tilapia islets have evolved along mammalian lines to be glucose sensitive while tilapia peripheral tissue have diverged widely. Using the same methods, tilapia were found to have a very limited tissue distribution of the insulin-independent glucose transporter, GLUT-1, which is responsible for basal glucose transport in mammalian cells. It is suggested that tilapia provide a naturally occurring GLUT-4 knockout model.

Epinephrine translocates GLUT-4 but inhibits insulin-stimulated glucose transport in rat muscle

We examined the effects of epinephrine (25, 50, and 150 nM) on 1) basal and insulin-stimulated 3-O-methylglucose (3-MG) transport in perfused rat muscles and 2) GLUT-4 in skeletal muscle plasma membranes. Insulin increased glucose transport 330-600% in three types of skeletal muscle [white (WG) and (RG) gastrocnemius and soleus (SOL)]. Glucose transport was also increased by epinephrine (22-48%) in these muscles (P < 0.05). In contrast, the insulin-stimulated 3-MG transport was reduced by epinephrine in all three types of muscles; maximal reductions were observed at 25 nM epinephrine in WG (-25%) and RG (-32.5%). A dose-dependent decrease occurred in SOL (-27% at 25 nM; -55% at 150 nM, P < 0.05). Insulin (20 mU/ml) and epinephrine (150 nM) each translocated GLUT-4 to the plasma membrane, and no differences in translocation were observed between insulin and epinephrine (P > 0.05). In addition, epinephrine did not inhibit insulin-stimulated GLUT-4 translocation, and the combined epinephrine and insulin effects on GLUT-4 translocation were not additive. The increase in surface GLUT-4 was associated with increases in muscle cAMP concentrations, but only when epinephrine alone was present. No relationship was evident between muscle cAMP concentrations and surface GLUT-4 in the combined epinephrine and insulin-stimulated muscles. These studies indicate that epinephrine can translocate GLUT-4 while at the same time increasing glucose transport when insulin is absent, or can inhibit glucose transport when insulin is present.

Effect of overexpressing GLUT-1 and GLUT-4 on insulin- and contraction-stimulated glucose transport in muscle

To examine the effects of GLUT-1 on GLUT-4-dependent, insulin-stimulated, and contraction-stimulated 2-deoxy-D-glucose (2-DG) transport, we overexpressed GLUT-1 in metabolically heterogeneous skeletal muscles [red and white tibialis anterior (TA) and extensor digitorum longus (EDL)] via 7 days of chronic electrical stimulation. GLUT-1 was increased 1.6- to 16.4-fold (P < 0.05). Basal 2-DG transport was increased 1.7- to 3.0-fold (P < 0.05) and was equal to (red TA and EDL; P > 0.05) or exceeded insulin-stimulated 2-DG transport by 50% (white TA; P < 0.05) in the control muscles. GLUT-4 was concomitantly overexpressed (2.1- to 4.4-fold; P < 0.05). Insulin-stimulated 2-DG transport was increased 1.6- to 2.5-fold (P < 0.05). During muscle contractions, 2-DG transport increased 9- to 12-fold (P < 0.05) in control muscles, but this was reduced by approximately 25% (P < 0.05) in muscles overexpressing GLUT-1 and GLUT-4 (red TA and EDL). In contrast, in the experiment, white TA contraction-stimulated 2-DG transport was increased 1.7-fold (P < 0.05). Therefore, overexpression of GLUT-1, when GLUT-4 is also overexpressed, does not impair insulin-stimulated 2-DG transport, although contraction-stimulated transport may be reduced in some muscles.

Reciprocal GLUT-1 and GLUT-4 expression and glucose transport in denervated muscles

We investigated in 3-day-denervated muscles 1) the expression of GLUT-1 in perineurial sheaths (PNS) and muscle, 2) the muscle fiber-specific changes in GLUT-1 and GLUT-4, and 3) changes in basal and insulin-stimulated 3-O-methylglucose transport. GLUT-1 was increased in both the PNS (P < 0.05) and in the muscle membranes (P < 0.05). GLUT-1 and GLUT-4 concentrations were changed reciprocally, in a fiber-dependent fashion [GLUT-1: red gastrocnemius (RG), +31%; white gastrocnemius (WG), +10%; GLUT-4: RG, -53%; WG, -16%]. Basal glucose transport was increased (P < 0.05), and this increase was correlated with the oxidative nature of the muscles (r = 0.97). Insulin-stimulated glucose transport was decreased in denervated muscles (P < 0.05). This was also related to the oxidative nature of the muscles (r = -0.88). The increase in basal glucose transport was correlated with the loss of insulin-stimulated transport (r = 0.95). Thus the increase in GLUT-1 compensates for the loss of GLUT-4, resulting in a 56% regain of the reduced insulin-stimulated glucose transport.

Increments in skeletal muscle GLUT-1 and GLUT-4 after endurance training in humans

We investigated the time course of training-induced changes in the expression of GLUT-1 and GLUT-4 in human skeletal muscle. Seven healthy males trained for 2 h/day (approximately 60% pretraining VO2peak) for 31 days (31D). Muscle biopsies were obtained before training (PRE) and after 5 (5D) and 31 days (31D) of training. Training resulted in progressive increases in muscle GLUT-4 with increasing training duration (PRE<5D<31D; P<0.01). Muscle GLUT-1 content was also increased (P<0.05) after training; however, the increase was not observed until 31D (131%). Increases in muscle hexokinase (HK) activity were complete by 5D (P<0.01). Muscle malate dehydrogenase activity was not elevated after 5D of training but was increased (+35%; P<0.01) at 31D. Results from this study show that increases in both GLUT-4 and HK represent early training-induced adaptations to prolonged exercise training. As training progresses, further increases in GLUT-4, but not HK, occur in conjunction with an increase in muscle mitochondrial potential and GLUT-1.

Stability of GLUT-1 and GLUT-4 expression in perfused rat muscle stimulated by insulin and exercise

In vivo exercise and insulin may change the concentrations of GLUT-4 protein and mRNA in muscle. We studied in vitro whether adaptations in glucose transporter expression are initiated during a single prolonged period of contractions or during insulin stimulation. Rat hindquarters were perfused at 7 mM glucose for 2 h with or without insulin (> 20,000 microU/ml) while the sciatic nerve of one leg was stimulated to produce repeated tetanic contractions. During electrical stimulation, contraction force decreased 93 +/- 1% (SE; n = 26) and muscle glycogen was markedly diminished (P < 0.05). Both contractions and insulin markedly increased glucose transport and uptake (P < 0.05). At the end of contractions, glycogen was higher in the presence of than in the absence of insulin (24 +/- 4 vs. 14 +/- 3 mumol/g for the soleus and 13 +/- 2 vs. 8 +/- 1 mumol/g for the red gastrocnemius, respectively; P < 0.05). In nonstimulated muscle, glucose transporter mRNA and protein concentrations were higher in the soleus than in the white gastrocnemius (GLUT-4 mRNA 184 +/- 18 vs. 131 +/- 36 arbitrary units; GLUT-1 mRNA 173 +/- 29 vs. 114 +/- 26 arbitrary units; GLUT-4 protein 0.96 +/- 0.09 vs. 0.46 +/- 0.03 arbitrary units; GLUT-1 protein 0.41 +/- 0.08 vs. 0.19 +/- 0.05 arbitrary units, respectively; P < 0.05). These concentrations were not changed by contractions or insulin. In conclusion, GLUT-1 and GLUT-4 mRNA and protein levels are higher in slow-twitch oxidative than in fast-twitch glycolytic fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of cyclic nucleotides (cAMP) on experimental HSV-I keratitis]

The authors report an experimental study on the effect of cAMP on HSV-I keratitis. Rabbit corneas developed typical dendritic keratitis on the 3rd day after inoculation of HSV-I. On the 9th day, the cAMP level in plasma significantly decreased from 174.9 +/- 20.2 to 52.1 +/- 18.2 pmol/ml, while the cGMP level increased. The cAMP level in aqueous humour also decreased, with an increase in cGMP level increased. The cAMP level in aqueous humour also decreased, with an increase in cGMP level. cAMP was used subconjunctivally for treatment of HSV-I keratitis. 48 hours after injection, the cAMP level in aqueous humour markedly rose from 11.1 +/- 2.0 to 35.6 +/- 12.9 pmol/ml and 6 days later to 65.0 +/- 30.9 pmol/ml, with concurrent decrease in cGMP level, and the ratio of cAMP/cGMP increased from 1.6 +/- 0.6 to 15.3 +/- 4.6. In the group of treatment by acyclovir, the level of cAMP in aqueous humour increased by 9.5 times after 3 days of treatment, with no remarkable effect on the cGMP level. These results showed that cAMP was equally effective as ACV in treatment of experimental HSV 1 keratitis. The antiviral action of cAMP was discussed and the pharmacological effect of cAMP approached.