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PubMed1990

Enhanced testosterone secretion in adult rams after establishment of a high-frequency, low-amplitude pattern of LH pulses in the nonbreeding season occurs without changes in the number or binding affinity of testicular LH receptors.

When the LH signal in the ram is changed from one of large and infrequent pulses to one of small and frequent pulses, the testes quickly become more responsive to LH and testosterone secretion is elevated, perhaps because the number and (or) binding affinity of testicular LH receptors have increased. An experiment was undertaken in the nonbreeding season (July) with 10 adult Dorset x Leicester x Suffolk rams that were about 3.5 years of age and 69 +/- 2 kg in body weight. Rams were given injections into the jugular vein of either 5 micrograms NIH-LH-S24 (in 1 ml saline) or vehicle every 80 min for 6 days. LH treatment produced a series of LH pulses that occurred three times more frequently and were 70% less in amplitude than pulses in the control rams, without causing mean LH concentration to increase. Endogenously produced LH pulses were not evident in the treated rams after LH injection began. The modified LH-pulse pattern elevated mean testosterone concentration by 150% (assessed on days 2 and 5), and caused the cumulative testosterone response to LH pulses, estimated by multiplying testosterone-pulse amplitude by frequency per 6 h, to increase progressively by 180% (days -2 through 5). Enhanced testicular steroidogenic activity, presumably due to greater enzymatic activity and cholesterol availability within Leydig cells, was not associated with increases in either the concentration or affinity of LH-binding sites in the testis (assessed on days 3 and 6).

Animals↗
PubMed2006

Effects of exposure duration and recovery time during pulsed exposures.

In pulsed toxicant exposures, the concentration, duration, and frequency of pulses can change through time. However, the conventional median lethal concentration (LC50) method cannot adequately predict the effects of pulsed exposure, because it is associated with fixed exposure duration and constant concentration and does not include postexposure (latent) mortality. Many studies that tried to address the effects of pulsed exposure only provided qualitative or semiquantitative predictions. Survival time experiments conducted here quantified the effect of exposure duration on latent mortality, and the effect of recovery time between two pulses on mortality during a second pulse also was examined. This was done by exposing amphipods (Hyalella azteca) to two contrasting toxicants, copper sulfate (CuSO4) and sodium pentachlorophenol (NaPCP). In the exposure duration experiments, the amphipods were exposed to two toxicant concentrations for three durations. No significant effect of duration on latent mortality was detected within the experimental range; however, duration still may need to be considered under other conditions. In the recovery time experiments, the amphipods were provided four recovery times, and their survivals during the second exposure were modeled. Recovery time had a significant effect on the second-exposure mortality. Given enough time, the amphipods could recover to a state similar to their original toxicant resistance state. The complete recovery time for CuSO4 was fivefold longer than that for NaPCP. It is important to quantify the effects of latent mortality, pulse duration and concentration, and recovery time for pulsed exposures. Survival analysis provides a better way to address these issues than does the conventional LC50 method.

Amphipoda↗
PubMed2006

Biophysical stimulation with pulsed electromagnetic fields in osteonecrosis of the femoral head.

BACKGROUND: Osteonecrosis of the femoral head is the end point of a disease process that results in bone necrosis, joint edema, and cartilage damage. It leads to joint arthritis that necessitates total hip arthroplasty in many patients. Because of its positive effects on osteogenesis and its chondroprotective effect of articular cartilage, pulsed electromagnetic field stimulation has been proposed as a method to prevent or delay the progression of osteonecrosis. METHODS: A retrospective analysis of the results of treatment with pulsed electromagnetic field stimulation of seventy-six hips in sixty-six patients with osteonecrosis of the femoral head was performed. Patients with Ficat stage I, II, or III osteonecrosis of the femoral head were treated with pulsed electromagnetic field stimulation for eight hours per day for an average of five months. Clinical and diagnostic imaging information was collected at the start of the treatment and at the time of follow-up. The primary end point analyzed was the avoidance of hip surgery, and the secondary end point was limiting the radiographic progression (according to Ficat stage) of osteonecrosis of the femoral head. RESULTS: Fifteen hips required a total hip arthroplasty; twelve of these hips were in patients with Ficat stage-III disease. The need for total hip arthroplasty was significantly higher in patients with Ficat stage-III disease than in patients with Ficat stage-I (p < 0.0001) or II (p < 0.01) disease at the beginning of treatment. Pulsed electromagnetic fields preserved 94% of Ficat stage-I or II hips. Furthermore, radiographic progression (according to Ficat stage) occurred in twenty hips (26%). Pain, present in all patients at the start of the treatment, disappeared after sixty days of stimulation in thirty-five patients (53%) and was of moderate intensity in seventeen patients (26%). CONCLUSIONS: The results of this study confirm that pulsed electromagnetic field treatment may be indicated in the early stages of osteonecrosis of the femoral head (Ficat stages I and II). Pulsed electromagnetic field stimulation may be able to either preserve the hip or delay the time until surgery. The authors hypothesize that the short-term effect of pulsed electromagnetic field stimulation may be to protect the articular cartilage from the catabolic effect of inflammation and subchondral bone-marrow edema. The long-term effect of pulsed electromagnetic field stimulation may be to promote osteogenic activity at the necrotic area and prevent trabecular fracture and subchondral bone collapse. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Adult↗
PubMed1988

Rapid reduction and return of surface insulin receptors after exposure to brief pulses of insulin in perifused rat hepatocytes.

Hepatic receptors are normally exposed to discrete pulses of insulin and glucagon at intervals of 8 to 16 min. Using a multicolumn system for perifusing hepatocytes, we investigated the effect of this pattern on the normal processing of the insulin receptor. Surface-receptor binding was measured in acid-washed cells harvested from individual columns. The number of high-affinity surface receptors fell to a nadir 1 min after the end of a 3-min square-wave pulse of insulin. The maximum reduction reached 45% of baseline at amplitudes of 1000 microU/ml or above. The number of surface binding sites returned to baseline 15 min after the end of the pulse, but the affinity constant of the high-affinity receptor was unchanged. The reduction of surface binding was dose dependent, with an ED50 of 251 +/- 34 microU/ml. Prolonging the pulse to 60 min did not affect the nadir or the rate of restoration of the surface-receptor population. The change in surface binding was reduced at 15 degrees C and abolished at 4 degrees C. After a pulse, the pattern of change was a period of rapid decline to a nadir (t1/2 less than or equal to 1 min) that persisted for 3-5 min, followed by restoration of surface binding that reached baseline in 10-15 min. This same pattern was present after six ED95 pulses delivered at intervals of 15 min. These data indicate that the internalization of hepatocyte surface receptors and their recycling and reinsertion into the plasma membrane can be entrained to pulses at the physiologic pulse frequency.

Animals↗
PubMed1984

Long-term superfusion of rat pituitary cells: interaction of 17 beta-estradiol with pulses of gonadotropin-releasing hormone on luteinizing hormone release.

In a series of four experiments, the temporal development of acute inhibitory and delayed stimulatory effects of 17 beta-estradiol (E) on luteinizing hormone (LH) release by superfused rat anterior pituitary cells pulsed with gonadotropin-releasing hormone (GnRH) was studied. Dispersed anterior pituitary cells from ovariectomized rats were cultured on Bio-Beads for 3 days and then placed in columns and superfused for up to 24 hr. During superfusion, the cells were exposed to GnRH pulses (3 X 10(-9) M, one 6-min pulse/hr). Cells treated with E (3 X 10(-10) M) either before (only 24 hr prior to superfusion) or before and during superfusion released significantly (P less than 0.05) more LH in response to the first few pulses of GnRH than cells treated with diluent. In contrast, cells treated with E only during superfusion initially released less GnRH-induced LH than cells treated with diluent. In a subsequent experiment, the inhibitory effect of E reached a maximum by 1.5 hr (P less than 0.01), and then gradually disappeared after 4.5 hr. Cells superfused simultaneously with E and fixed "low"-dose GnRH (5 X 10(-10) M) pulses did not exhibit enhanced LH responses with time to that dose of GnRH. However, E-superfused cells responded more than diluent-superfused cells to subsequent stimulation with a higher-dose GnRH pulse. Superfusion of cells with E for 16.5 hr in the absence of GnRH pulses also did not increase release of LH to low-dose (5 X 10(-10) M) pulses of GnRH, yet did cause a transitory increase to subsequent high-dose (10(-8) M) GnRH pulses. In conclusion, these results demonstrate the direct biphasic inhibitory then stimulatory effects of E on GnRH-induced LH release by superfused rat anterior pituitary cells. Expression of the stimulatory effect of E is related to the dose of GnRH.

Animals↗
PubMedDate not supplied

Lamellar refractive surgery with scanned intrastromal picosecond and femtosecond laser pulses in animal eyes.

PURPOSE: To evaluate the use of scanned intrastromal picosecond and femtosecond laser pulses in lamellar refractive surgical procedures. METHODS: Intrastromal corneal photodisruption was performed in fresh porcine and primate cadaver eyes with a solid-state femtosecond laser. Laser pulses were focused 150 to 200 microns below the epithelial surface and scanned in a spiral pattern to create a plane. A flap was made by scanning an arc pattern from the plane of the spiral to the surface of the cornea. Tissue plane separation was graded using a standard scale, while internal surfaces were analyzed by scanning electron microscopy. Comparison was made to a picosecond laser system using the same delivery system device. Creation of a stromal lenticule for in situ keratomileusis was also demonstrated and compared with both laser systems. RESULTS: For femtosecond pulses, tissue separation was achieved best with pulse energies from 4 to 8 microJ and spot separations from 10-15 microns. Picosecond pulses accomplished less complete separations with pulse energies of 25 microJ and spot separations from 10 to 20 microns. Surface quality corresponded to dissection results, with high-grade dissections resulting in a smooth surface appearance, versus a more irregular surface for low-grade dissections. Although high-grade dissections could be created with picosecond pulses (with optimal parameters) in ex vivo porcine eyes, only femtosecond parameters produced similar results in ex vivo primate eyes. CONCLUSION: In contrast to previous attempts using picosecond lasers which require additional mechanical dissection, high precision lamellar refractive surgery may be practical with femtosecond laser pulses.

Animals↗
PubMed2006

Pulse granulomas detected in gallbladder, fallopian tube, and skin.

CONTEXT: Foreign material typically elicits reactions dominated by multinucleated giant cells. Pulse granulomas are peculiar reactions to particles of food that are characterized by clusters of small to medium-sized hyaline rings. Pulse granulomas are rare and have occupied only the lungs, in association with aspiration, and the alimentary canal, in association with oral pathology, colonic diverticula, and a rectal mass. OBJECTIVE: To report pulse granulomas that occupied previously unrecognized sites and to alert pathologists to the diagnostic pitfall of mistaking pulse granulomas for other entities. DESIGN: We retrospectively reviewed 3 recently encountered cases that involved pulse granulomas in the gallbladder, fallopian tube, and skin. RESULTS: In all cases, pulse granulomas were associated with fistulae involving the gastrointestinal tract. One fistula was clinically occult. Microscopy showed barium-laden histiocytes admixed with hyaline rings, with or without vegetable matter, confirming fistulae involving the gastrointestinal tract. Absence of other features of chronicity, including sarcoid-type granulomas and Langhans-type giant cells, helped to essentially exclude Crohn disease. In 1 case, hyaline rings of pulse granulomas closely resembled hyaline vasculopathy of amyloidosis, diabetes, or hypertension. Surprisingly, polariscopy failed to detect any vegetable matter. In 1 case, negative polariscopy contributed to the difficulty in finding rare vegetable matter. CONCLUSIONS: We demonstrated that pulse granulomas can occur outside the lungs and alimentary canal, and can be associated with fistulae involving the gastrointestinal tract. Awareness of this finding is necessary to avoid confusion with Crohn disease and hyaline vasculopathy. Polariscopy may fail to detect vegetable matter.

Aged↗
PubMed1993

Risk for sustained amenorrhea in patients with systemic lupus erythematosus receiving intermittent pulse cyclophosphamide therapy.

OBJECTIVE: To determine the risk for secondary amenorrhea after pulse cyclophosphamide therapy in premenopausal women with systemic lupus erythematosus. DESIGN: Controlled, retrospective clinical study. SETTING: Government referral-based research hospital. PATIENTS: Thirty-nine women younger than 40 years treated with pulse cyclophosphamide therapy for active lupus nephritis or neuropsychiatric lupus. Sixteen women who received pulses of intravenous methylprednisolone were controls. INTERVENTIONS: Sixteen patients received pulse cyclophosphamide (0.5 to 1.0 g/m2 body surface area) monthly for a total of 7 doses (short-CY), and 23 patients received 15 or more doses (long-CY). Control patients were treated with monthly pulses of methylprednisolone (1.0 g/m2) for a total of nine doses. MEASUREMENTS: Rates of amenorrhea were evaluated according to duration of treatment (number of doses) and age at the initiation of pulse therapy. RESULTS: Two of 16 patients (12%) in the Short-CY group and 9 of 23 (39%) in the long-CY group developed sustained amenorrhea (P = 0.07). Rates of sustained amenorrhea (short- and long-CY) according to age at the start of pulse therapy were: < or = 25 years, 2/16 (12%); 26 to 30 years, 4/15 (27%); > or = 31 years, 5/8 (62%) (P = 0.04). The increased risk for sustained amenorrhea in patients treated with long-CY was most evident in patients older than 25 years (short-CY [2/12] compared with long-CY [7/11]; P = 0.03). Three other patients with short-CY had reversal of amenorrhea fewer than 12 months after cessation of therapy. Amenorrhea was not observed in any of the 16 control patients. CONCLUSIONS: Intermittent pulse cyclophosphamide therapy in patients with systemic lupus erythematosus is associated with sustained amenorrhea, which is related to both age and number of doses of cyclophosphamide.

Adult↗
PubMedDate not supplied

Post-gel shrinkage with pulse activation and soft-start polymerization.

This study investigated the influence of pulse activation and soft-start polymerization regimens on the post-gel shrinkage of a visible light-activated composite resin (Z100). A light-cure unit (BISCO VIP) that allowed for independent command over time and intensity was used. The six light-curing modes that were examined include: Control (C)-400 mW/cm2 [40 seconds]; Pulse Delay I (PDI)-100 mW/cm2 [3 seconds], delay [3 minutes], 500 mW/cm2 [30 seconds]; Pulse Delay II (PDII)-200 mW/cm2 [20 seconds], delay [3 minutes], 500 mW/cm2 [30 seconds]; Soft-start (SS)-200 mW/cm2 [10 seconds], 600 mW/cm2 [30 seconds]; Pulse Cure I (PCI)--two 400 mW/cm2 [10 seconds] and one 400 mW/cm2 [20 seconds] pulses with 10 seconds interval between; and Pulse Cure II (PCII)-two 400 mW/cm2 [20 seconds] pulses with 20 seconds interval between. A strain-monitoring device measured the linear polymerization shrinkage associated with the various cure modes during and post light polymerization up to 60 minutes. Five specimens were made for each cure mode. Data was analyzed using one-way ANOVA and Scheffe's post-hoc test at significance level 0.05. Post-gel shrinkage associated with PDI was significantly lower than with PDII, SS and PCI immediately post light-polymerization. At one-minute post light polymerization, PDI had significantly lower shrinkage compared to PDII and SS. Significant differences in shrinkage were observed between PDI and SS only at 10, 30 and 60 minutes. At all time intervals, no significance in post-gel shrinkage was observed between the control and all-pulse activation/soft-start polymerization regimens.

Analysis of Variance↗
PubMed2004

Validation of the Nonin 8600V Pulse Oximeter for heart rate and oxygen saturation measurements in rats.

This report validates the use and limitations of the Nonin Pulse Oximeter for measuring heart rate and oxygen saturation in rats. Eight anesthetized Sprague-Dawley rats were intubated and catheterized. Oxygen saturation was directly measured from arterial blood by using a Radiometer OSM3 Hemoximeter adjusted for rat blood as well as indirectly by using the Nonin Pulse Oximeter. Oxygen saturation was changed by varying the level of inhaled oxygen. Heart rate was measured in two ways: 1) by using the signal from the Nonin Pulse Oximeter and 2) by counting the pressure pulses from the transduced blood pressure. There was excellent agreement between heart rate values measured by the Nonin Pulse Oximeter and that measured by counting the pulses from the arterial blood pressure recording. The Nonin Pulse Oximeter underestimated oxygen saturations by about 3% to 5% compared to the Hemoximeter. Overall, the pulse oximeter reflected important trends in oxygen saturations, making it a useful tool for laboratory animal medicine.

Animals↗
PubMed2004

[Investigation on specific killing acute leukemia cell reaction of the cytotoxic T lymphocyte induced by dendritic cell pulsed with frozen-thawed antigen].

We investigated the effects of dendritic cell (DC) pulsed with acute leukemia cell frozen-thawed antigen on inducing the cytotoxic T lymphocyte (CTL) to get specific anti-tumor activity in vitro. DC was generated from healthy human bone marrow mononuclear cell (BMMC) in the presence of granulocyte/macrophage-colony stimulating factor(GM-CSF), interleukin-4 (IL-4) in vitro. DC pulsed with acute leukemia cell frozen-thawed antigen was co-cultured to induce T cell into specific CTL. Then we observed the effects of CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen killing acute leukemia cell specially and the influence of dendritic cell affecting the function and CD expression on CTL. The levels of CD1a, CD86, HLA-DR expression on DC pulsed with acute leukemia cell frozen-thawed antigen were obviously higher than those before culture (P<0.01). There were more CD3+CD8+ T cells in the CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen, compared with those in the T cell uncultured group (P<0.01). The CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen significantly had higher activity in killing acute leukemia cell than in killing k562 cell (P<0.01), and the CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen was also more effective for killing acute leukemia cell as compared with the CTL induced by DC simply, T cell co-cultured with IL-2 and T cell simply (P<0.01). The DC generated from human bone marrow mononuclear cell (BMMC) in the presence of granulocyte/macrophage-colony stimulating factor (GM-CSF), interleukin-4 (IL-4) was CD14- CD1a+CD83+DC, and it could also induce the cytotoxic T lymphocyte (CTL) to get specific anti-tumor activity in vitro. Otherwise,the increasing of CD3+CD8+ T cells in the CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen implied the main role of the CD3+CD8+ T cells in the anti-tumor immunity.

Antigens, Neoplasm↗
PubMed2005

Does perioperative pulse oximetry improve outcome? Seeking the best available evidence to answer the clinical question.

The aim of this chapter is to clarify the effect of perioperative monitoring with pulse oximetry and to identify the adverse outcomes that might be prevented or improved by its use. Trials were identified by computerized searches of The Cochrane Library, MEDLINE and EMBASE, and by checking the reference lists of trials and review articles. All controlled trials that randomized patients to either pulse oximetry or no pulse oximetry during the perioperative period, including the operating and recovery room, were included in the search. Pulse oximetry monitoring was shown to substantially reduce the extent of perioperative hypoxaemia, enabling the detection and treatment of hypoxaemia and related respiratory events, and promoting several changes in patient care. The implementation of perioperative pulse oximetry monitoring does not significantly reduce the number of postoperative complications, but the question remains whether pulse oximetry can improve outcomes in other situations. Pulse oximetry has been adopted all over the world in clinical practice as a tool that guides anaesthesiologists in the daily management of patients: in teaching situations, in emergencies, and especially in the care of children. Given the relatively small number of patients studied in these trials and the rare events being sought, the studies of perioperative monitoring with pulse oximetry were not able to show an improvement in the outcomes studied.

Evidence-Based Medicine↗
PubMed2005

[An in vitro study of specific antitumor immunity induced by dendritic cells pulsed with tumor cell lysates from patients with hepatocellular carcinoma].

OBJECTIVE: To investigate T cell-mediated antitumor effects of dendritic cells (DCs) pulsed with tumor lysates in patients with hepatocellular carcinoma (HCC) in vitro. METHODS: DCs isolated from peripheral blood mononuclear cells of HCC patients were cultured and proliferated in vitro by using recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) and interleukin-4 (rhIL-4), and then were pulsed with autologous hepatoma cell lysates. The phenotypes of the DCs were assayed by flow cytometry. The concentration of IFN-gamma and IL-12 were measured in culture supernatants by ELISA. The ability of DCs pulsed with hepatoma cell lysates to stimulate proliferation of autologous T lymphocytes (CTL) was tested by thymidine incorporation method. The specific cytolytic activity of CTL was assessed by MTT method. RESULTS: The hepatoma cell lysates pulsed DC vaccines led to up-regulation of CD1a, CD40, CD86 and HLA-DR. Concentrations of IFN-gamma and IL-12 were increased more in the hepatoma cell lysate pulsed DCs group than those in the unpulsed DCs group, the hepatoma cell lysate group and control group. The proliferation of T-cells was markedly enhanced in the hepatoma cell lysate pulsed DCs group than that in the others. The CTL stimulated by the hepatoma cell lysate pulsed DCs had much higher cytotoxicity to autologous hepatoma cells (killing rate: 81.72%+/-9.49%), as compared with HepG2 and HNE-1 tumor cells (killing rate: 49.37%+/-11.21% and 17.14%+/-5.65%, respectively). CONCLUSION: The hepatoma cell lysate pulsed DC vaccines can induce an effective and specific anti-hepatoma effect.

Adult↗
PubMed2006

[Insulin ultradian pulse model of individuals with overweight and impaired glucose tolerance].

OBJECTIVE: To study the characteristics of insulin ultradian pulses of individuals with normal glucose tolerance, overweight, and impaired glucose tolerance (IGT). METHODS: Blood samples were taken every 15 minutes from 10 individuals with normal glucose tolerance, 6 individuals with overweight and 3 individuals with IGT for 24 hours. Blood glucose, insulin, and C-peptide of every time point were measured. Standard diet was used in the study. The 24 h-ISR profile was submitted to time series analysis. RESULTS: (1) As given standard diet, 2 to 4 pulses occurred after each meal, 3 to 4 pulses occurred during the night, and 12 to 15 pulses occurred in the whole 24-hour period. The first insulin pulse always occurs 30 to 60 minutes after meal. The maximum amplitude of pulse occurred 45 to 90 minutes after meal. These characteristics were not significantly different among the 3 groups. (2) The average amplitude of 24-hour insulin secretion rate (ISR) of the normal group was 357 pmol/min +/- 11 pmol/min, significantly lower than those of the overweight and IGT groups (820 pmol/min +/- 37 pmol/min and 666 pmol/min +/- 53 pmol/min respectively, both P < 0.05). (3) The average periodicity of insulin ultradian pulse were 75 min and 75 - 90 min in the control group and overweight group respectively. The periodicity of insulin ultradian pulse in the IGT group was undefined. (4) The cross-correlation function were 0.72 +/- 0.11, 0.80 +/- 0.11 and 0.51 +/- 0.11 respectively in the normal, overweight, and IGT groups. CONCLUSION: (1) As given standard diet, the occurring numbers and time of insulin ultradian oscillations are not statistically significantly different among the normal, overweight, and IGT groups. (2) The insulin secretion amplitude is increased in the overweight and IGT groups. (3) The rhythm and concomitance coefficient of the ISR and glucose are low in the individuals with IGT.

Adult↗
PubMed2006

Effects of lower fluence pulsed dye laser irradiation on production of collagen and the mRNA expression of collagen relative gene in cultured fibroblasts in vitro.

BACKGROUND: Lower fluence of 585-nm flashlamp-pumped pulsed dye laser has been successfully used as a nonablative technique in the treatment of wrinkles. The objective of this study was to evaluate the effect of the pulsed dye laser (585 nm) on the production of collagen and the mRNA expression of collagen related gene in fibroblasts in vitro. METHODS: Cultured fibroblasts were treated with a 585-nm flashlamp-pumped pulsed dye laser (fluence 3 J/cm(2), 4 J/cm(2), spot size 7 mm, pulse duration 450 micros). The production of collagen and the mRNA expression of transforming growth factor (TGF)-beta1, SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen alpha1, alpha2 in fibroblasts were investigated by colorimetry or real time polymerase chain reaction. RESULTS: The production of collagen was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm(2) (P < 0.001). The mRNA expression of TGF-beta1, SMAD2, SMAD3, SMAD4, SMAD7 and procollagen I was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm(2) (P < 0.001). No significant difference of mRNA expression of SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen was found between controls and fibroblasts treated with pulsed dye laser with a fluence of 4 J/cm(2) (P > 0.05). CONCLUSIONS: Lower fluence (3 J/cm(2)) pulsed dye laser increased the collagen production in fibroblasts by up-regulating TGF-beta1, SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen mRNA expression. These may be the reason it can be effectively used in the treatment of wrinkles.

Analysis of Variance↗
PubMed1988

Uptake of fluorescence-labeled dextrans by 10T 1/2 fibroblasts following permeation by rectangular and exponential-decay electric field pulses.

The uptake of fluorescence-labeled dextrans by adherent 10T 1/2 murine fibroblasts following electric field pulse application was used as a criterion for the efficiency of electropermeation. The cells in monolayers were permeated by immersing a coaxial electrode in culture dishes. The percentage of cells which exhibited fluorescence uptake following electric field pulse application was measured at independently varying pulse field strength and pulse length. Dextrans with molecular weights equal to or higher than 41,000 dalton require higher field strength or longer pulse time to penetrate the cells. There is no detectable advantage of using a rectangular pulse against using an exponential decay pulse of similar power. The uptake was proportional to the product of the pulse amplitude and duration over the experimental range of 40-950 microseconds and 0.1-14.5 kV/cm. Cell survival decreases at the upper end of this range. The result provides a direct comparison of electric parameters which so far have not been standardized with regard to cell electropermeation.

Animals↗
PubMed1979

Inhibition of thymidine incorporation into epidermal and dermal DNA of HRS/J mice after a Colcemid pulse.

The introduction of a Colcemid pulse, which is known to inhibit microtubulin assembly and thereby influence cellular events dependent on the assembly, delayed the normal passage of G1 cells to S-phase. Experimental support for this hypothesis was obtained by the pulsing of cultured inbred HRS/J mouse skin for 30 minutes with 20 micrograms Colcemid/ml and by measurement of thymidine (dThd) incorporation for a 4-hour incubation period at different intervals after the pulse. Incorporation of dThd into epidermal and dermal DNA was maximally inhibited 9.5 and 17.5 hours after the Colcemid pulse. Maximal inhibition and minimal inhibition of dThd incorporation were observed 17.5 hours after different concentrations of Colcemid (1--30 micrograms/ml) were pulsed. Maximal inhibition of dThd incorporation occurred after pulsing with 20 micrograms Colcemid/ml. The acceleration of G0 or G1 events to S-phase in proliferative cells caused by mild epidermal stripping was also inhibited after the addition of the Colcemid pulse. The data suggest a time relationship between the Colcemid pulse, the subsequent disruption of microtubulin structure, and the inhibition of dThd incorporation into epidermal and dermal DNA. The intact microtubulin structure is apparently essential for the normal intracellular dependency among the cell membrane, the cytoskeleton structure, and the cell nucleus and occurs when the cells transit from G1 to S-phase.

Animals↗
PubMed1988

Shielding properties of laser-induced plasmas in ocular media irradiated by single Nd:YAG pulses of different durations.

Shielding of laser pulses by plasmas generated in ocular media has been experimentally investigated using single Nd:YAG laser pulses of different durations, ranging from several nanoseconds (ns) to a few tens of picoseconds (ps), both in saline solution and extracted calf vitreous. At the respective threshold radiant exposures for breakdown in saline (259 mJ/cm2 for 7 ns, 20.5 mJ/cm2 for 220 ps and 4.7 mJ/cm2 for 30 ps pulses) the single pulse energy transmission is found to be about 74% for 7 ns, 55% for 220 ps and 50% for 30 ps, thus showing that shielding of laser-induced plasmas is more effective for shorter pulses than for longer pulses. Moreover, the decrease in transmission with increasing radiant exposure is faster in the picosecond case than in the nanosecond case. These results show that direct irradiation of the retina is, to some extent, present especially near threshold. In the case of picosecond pulses, a comparison with published results indicates that shielding between subsequent pulses in a train is likely to occur only to a very limited extent.

Culture Media↗