Interleukin-1 beta activates c-jun NH2-terminal kinase subgroup of mitogen-activated protein kinases in mesangial cells

We investigated whether JNK is activated by interleukin-1 beta (IL-1 beta) in mesangial cells. We performed in-gel kinase assays with His-c-jun-(1-79), which contains the amino-terminal activation domain of c-jun and a mutant His-c-jun in which Ser-63 and Ser-73 of His-c-jun were mutated to Ala as the substrates. JNK1 (p45) and JNK2 (p54) isoforms phosphorylated His-c-jun in mesangial cells. IL-1 beta produced a time- and concentration-dependent increase in JNK activity. IL-1 beta did not phosphorylated the mutant, His-c-jun. The IL-1 beta-activated JNK activity was independent of serum and suppressed by neither tyrosine kinase inhibitors nor protein kinase C inhibitors. JNK was also stimulated by anisomycin and okadaic acid but not by phorbol 12-myristate 13-acetate. The protein synthesis inhibitors and okadaic acid potentiated the IL-1 beta-induced JNK activity. Together, these studies indicate that the novel JNK group of protein kinases may play an important role in the signal transduction pathway initiated by proinflammatory cytokines, such as IL-1 beta in mesangial cells.

Injury to vascular endothelial cells and the change of plasma endothelin level in dogs with gunshot wounds

The purpose of this study was to evaluate the relationship between injury to endothelial cells and the plasma endothelin level after gunshot wounds. Forty dogs were divided into four groups. The dogs in group 1 served as a control. The dogs in groups 2,3, and 4, respectively, were shot in both hind legs, in the hypogastric part of the abdomen, or in the right chest by military bullets (5.56 mm or 7.62 mm). After wounding, blood samples were taken at different intervals and the number of circulating endothelial cells (CEC), an indicator of injury to vascular endothelial cells (VEC), and the level of plasma endothelin were measured. Results showed that the CEC number increased in all groups immediately after wounding and showed a peak value at 10 minutes and at 6 hours. The change in plasma endothelin level paralleled that of the change of CEC number, and a linear relationship was found between them. These results suggest that, in gunshot wounds, extensive injury to VEC may be the result of the temporary cavity and shock waves produced by high velocity missiles striking the body and causing secretions of endothelin. The mechanism of injury to VEC after a gunshot wound in discussed in this paper.

[The microscopic vasculitis in tongue]

This is the first report of 16 cases with microscopic vasculitis of the tongue in Chinese literatures. The clinical manifestations and histopathology of the disease were described. The treatment of promoting blood circulation to remove blood was used stasis. Probably the microscopic vasculitis plays an importment role in the glossodynia.

Lipid composition in scrapie-infected mouse brain: prion infection increases the levels of dolichyl phosphate and ubiquinone

The neutral and phospholipid composition of mouse brain infected with scrapie prions was investigated. During the later stages of this disease, the level of dolichol decreased by 30% whereas the level of dolichyl phosphate increased by 30%. In terminally ill mice, there was also a 2.5-fold increase in both total ubiquinone and its reduced form. Furthermore, alpha-tocopherol was elevated at this stage by 50%. In contrast, no changes were observed in phospholipid amount, in phospholipid composition, and in phosphatidylethanolamine plasmalogen content during the entire disease process. The fatty acid and aldehyde composition of individual phospholipids remained unaltered as well. No modifications could be detected in cholesterol content. Thus, the majority of membrane lipids in scrapie-infected mouse brain are modified in neither quantity nor structure, but specific changes occur to a few polyisoprenoid lipids. This specificity indicates that, although prions accumulate in lysosomes, the infection process is not associated with a general membrane destruction caused by lysosomal enzyme leakage.

[The effects of retinoic acid on the ultrastructure of cultured fibroblasts]

The paper reports the effects of retinoic acid on the ultrastructure of cultured fibroblasts. Electron microscopic observation (SEM and TEM) showed that fibrous substances on the cell surface and outside the cell had decreased. The results indicated that retinoic acid inhibits collagen synthesis of fibroblasts. The possible mechanism of the effect of retinoic acid in the treatment of scar is discussed.

[Risk of malignant changes in hydatidiform mole complicated with pregnancy induced hypertension]

OBJECTIVE

To investigate the prognosis of patients of hydatidiform mole (HM) who complicated with pregnancy induced hypertension (PIH) and to suggest that PIH may serve as a risk factor for malignant change in molar pregnancy.

METHODS

From 1962 to 1992, 161 patients of HM including 33 cases with PIH and 128 cases of normotension were managed and followed at the PLA General Hospital. The definition of malignant sequelae was that abnormal hCG level was lasting at least 8 weeks after molar evacuation or metastatic lesions was found.

RESULTS

15 of 33 patients with PIH developed metastatic invasive moles (45.5%) and 13 of them metastatic tumors were found before molar evacuation. 12 of 128 cases of normotension had malignant thanges including 1 choriocarcinoma and 11 invasive mole (9.4%) and among them only one had metastatic lesions before molar evacuation.

CONCLUSIONS

The incidence (45.5%) of malignant changes in patients complicated with PIH was significantly higher than that in normotensive patients (9.4%) (P < 0.01). In addition, they had early metastatic lesions. This study suggests that PIH may serve as a risk factor for malignant change in molar pregnancy.

Gangliosides inhibit PDGF-induced signal transduction events in U-1242 MG human glioma cells

In this study we investigated the responses of intracellular calcium ([Ca2+]i) and protein kinase C (PKC) to PDGF in U-1242 MG cells. PDGF-BB stimulated [3H]PDBu binding approximately 2-3 fold. This response was inhibited by preincubating the cells with an inhibitor of phospholipase C (PLC), U73122, suggesting that PLC mediates the induction of PKC translocation by PDGF. PDGF also increased the concentration of [Ca2+]i that was attenuated in a calcium-free medium. This indicates that PDGF-induced elevation of [Ca2+]i is mainly due to influx of extracellular calcium. PDGF-stimulated translocation of PKC was inhibited by the intracellular calcium buffer BAPTA/AM. All gangliosides studied except GM3 inhibited these responses with similar efficacy. Collectively, these results indicate that the signal transduction pathway initiated by PDGF leading to PKC translocation in U-1242 MG cells is intact, and this pathway is inhibited by several gangliosides.

A minipig model for urodynamic evaluation of infravesical obstruction and its possible reversibility

PURPOSE

The aim of our study was to create reproducible partial bladder outlet obstruction and to evaluate the resulting urodynamic changes.

MATERIALS AND METHODS

Thirty-one female Yucatan microswine were randomly divided into obstructed and control groups. In the obstructed group of 21 animals, an artificial 4.5-cm. sphincter cuff was placed around the bladder neck. Fourteen of these minipigs were eventually deobstructed. In the controls (unobstructed sham-operated group), the sphincter cuff was removed prior to closure. Urodynamic measurements were conducted at 2, 4, 8 and 12 weeks postobstruction in conscious animals restrained in specially designed adjustable cages.

RESULTS

(with all pressures in cm.H2O): 1) Unobstructed sham controls: Pdet,open 28.8 Pdet (Qmax) 22.5, Qmax 30.8 ml. per second, Pdet,isv 61.7, urethral resistance relation (URA) 7.7 cm.H2O, and Watts factor (WF) 4.7 W/m.2; 2) Obstructed group: Pdet,open 85.2; Pdet (Qmax) 94.4, Qmax 5.6 ml. per second, Pdet,isv 135.2, mean URA 74.3 cm.H2O and WF 13.5 W/m.2; 3) Deobstructed group: Pdet,open 39.9, Pdet (Qmax) 25.9, Qmax 25.0 ml. per second, Pdet,isv 58.0, mean URA 8.9 cm.H2O and WF 5.4 W/m.2.

CONCLUSION

This animal model of reversible infravesical obstruction has given consistent and reproducible pressure flow data in the conscious, upright state.

Arachidonic acid inhibits hCG-stimulated progesterone production by corpora lutea of primates: potential mechanism of action

Arachidonic acid (AA) is a precursor of metabolites known to affect the corpus luteum (CL) in many species, including primates. We have shown that some of these products (prostaglandins F2 alpha and E2) inhibit pro-gesterone (P4) production and activate the phosphatidylinositol (PI) pathway in CL of rhesus monkeys. A direct role of AA in luteal function has also been suggested. The current experiments were designed to investigate the effect of AA on P4 synthesis and to examine the ability of AA to activate the PI pathway in CL of rhesus monkeys. Basal and hCG-stimulated P4 production by luteal cells collected during the midluteal phase was measured after treatment with AA (1, 5, and 10 microM) or linoleic acid (1, 5, and 10 microM). Dispersed cells (50,000/tube) were incubated at 37 degrees C for 2 h. AA elicited a dose-dependent decrease in hCG-stimulated, but not in basal, P4 production. hCG-stimulated P4 production was reduced (P < 0.01) at AA doses of 5 microM (12.1 +/- 1.5 ng/mL) and 10 microM (8.6 +/- 1.8 mg/mL) to hCG alone (18 +/- 1.6 ng/mL). There was no significant effect of 1 microM AA (15.2 +/- 1.6). Response to linoleic acid was dissimilar and was not dose-dependent. Viability of cells was not affected by any treatment. Indomethacin, a prostaglandin synthesis inhibitor, and nordihydroguaiaretic acid, an inhibitor of lipoxygenase, did not interfere with the inhibitory effect of AA. Activation of the PI pathway was assessed by monitoring the hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2) to inositol phosphates and by monitoring increases in intracellular free calcium concentrations ([Ca2+]i) in individual cells. Moreover, the ability of AA to activate protein kinase C (PKC) in luteal cells was measured using a [3H]phorbol dibutyrate (PDBu) binding assay. AA did not alter PIP2 hydrolysis or [Ca2+]i, however, AA (10 microM) increased specific binding of [3H]PDBu to luteal cells (P < 0.05). We conclude that AA inhibits hCG-stimulated P4 production by primate luteal cells. AA exerts this action without being converted to prostaglandins or leukotrienes. This inhibition may be mediated through the activation of PKC. These results suggest a possible role for AA in the regulation of luteal function in primates, and that PKC-activation by AA may promote its effects.

Remeasurement at high resolving power in fourier transform ion cyclotron resonance mass spectrometry

The Fourier transform ion cyclotron resonance mass spectrometry remeasurement experiment is demonstrated and evaluated under high resolution conditions. Signal-to-noise enhancement is observed for isotopically resolved bovine insulin peaks at a resolution of ∼ 31,000 (full width at half height). The experiment is sensitive to spacecharge effects and resultant changes in scan-to-scan signal-to-noise and resolution. Coulombic repulsion in the ion cloud during the high resolution remeasurement experiment can cause the cyclotron frequency to shift through the duration of the experiment, which results in broadened peak shapes when individual remeasurement spectra are coadded. By either reducing the number of ions in the cell or allowing the ion cloud to diffuse during the lifetime of the experiment, high resolution remeasurement spectra can be coadded without peak broadening or degradation of signal-to-noise ratio.

Control of atrial natriuretic factor by right and left atrial distension in pregnant sheep

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.

Effects of acupuncture on immunoglobulins in patients with asthma and rheumatoid arthritis

The effects of acupuncture on immunoglobulins in patients with asthma and rheumatoid arthritis were studied. After acupuncture, in 20 patients with asthma, IgG increased (P < 0.01), IgM and IgE decreased (both P < 0.01), while IgA did not change markedly (P > 0.05); in 12 patients with rheumatoid arthritis, after acupuncture IgG, IgA and IgM decreased (P < 0.05, 0.05, and 0.01, respectively), while IgE did not change evidently. The results observed in these 32 patients indicate that acupuncture exerts modulation action on immunoglobulins of the human body, and that patients with asthma and rheumatoid arthritis responded effectively to acupuncture therapy, the latter might be related to the reinforcement of the immunological function by acupuncture.

[The relations of corneal, lenticular and total astigmatism]

PURPOSE

To determine the relations of corneal, lenticular and total astigmatism and the changes of the astigmatism with age.

METHOD

Out-patients with refractive errors were refracted with retinoscope after using cycloplegic drops and measured the radii of anterior corneal curvature.

RESULT

One hundred and ninety-four cases (382 eyes) with refractive errors were studied. Of the eyes 67.9% had regular corneal astigmatism, 68.1% irregular lenticular astigmatism and 60.7% regular total astigmatism, 88.5% of the corneal astigmatism has the same quality as the total astigmatism. The total astigmatism in 46% of the eyes included the summation of corneal and lenticular astigmatism, but in 41.3% of the eyes irregular lenticular astigmatism corrected the regular corneal astigmatism. The astigmatism of cornea, lens and total astigmatism changed from regular to irregular with the increase of age. The linear correlation analysis showed a positive correlation between the power of horizontal corneal refraction and age, and a negative corrlation between the power of vertical corneal refraction and age.

CONCLUSION

The shape of cornea was the major cause of total astigmatism. The influence of lens on the total astigmatism was different. The reasons for the change of the total astigmatism from regular to irregular with the increase of age were the changes of the power of corneal refraction, particularly the increase of the power of horizontal corneal refraction and lenticular irregular astigmatism.

Zaprinast accelerates recovery from established acute renal failure in the rat

Atrial natriuretic factor (ANF) has been demonstrated to be effective in the treatment of acute renal failure (ARF) in both rat and humans. The biological effects of ANF are presumed to be mediated by the generation of intracellular 3',5'-cyclic guanosine monophosphate (cGMP). Therefore, the current investigation examined whether zaprinast (M&B 22948), a guanosine 3',5'-cyclic monophosphate (cGMP)-specific phosphodiesterase inhibitor, would be effective in the treatment of established acute renal failure in the rat. Acute renal failure was induced by 60 minutes of bilateral renal artery clamping. Twenty-four hours after the ischemic insult, rats received either vehicle (5% Dextrose), zaprinast (0.03 or 0.3 mg/kg/min) or ANF24 (0.2 micrograms/kg/min) intravenously for four hours. Renal function, as measured by daily serum creatinine (days 1 to 7) and day 2 inulin clearances, was dramatically improved by zaprinast but not ANF treatment. Forty-eight hours post-renal ischemia, glomerular filtration rate (GFR) was 0.14 +/- 0.04 (ml/min/100 g body wt) in the vehicle and 0.94 +/- 0.29 in the zaprinast treated animals. To evaluate the mechanism by which zaprinast accelerated renal recovery, we measured regional blood flow in the postischemic rat kidneys during drug treatment with a laser doppler flowmeter. Both high and low dose zaprinast significantly increased cortical (17%) and outer medullary blood flow (40% and 60%), an effect not seen with ANF. In summary, zaprinast is effective in the treatment of established ischemic ARF. The mechanism by which zaprinast accelerates renal recovery is due to its unique ability to stimulate regional renal blood flow and increase intracellular cGMP in the setting of tissue ischemia.

Effects of angiotensin II on plasma atrial natriuretic factor in nonpregnant and pregnant ewes

The release of atrial natriuretic factor (ANF) is primarily determined by atrial stretch, but may also be modulated by circulating angiotensin II (AngII). During pregnancy, the circulating concentrations of both ANF and AngII are increased. To further define possible effects of AngII on ANF release, four doses of AngII (0.5, 5, 20, 40 ng.kg-1.min-1) were intravenously infused into five nonpregnant and five pregnant (105-140 days of gestation) ewes alone and during the simultaneous infusion of sodium nitroprusside at doses sufficient to abolish the pressor effects of AngII. Mean arterial pressure (MAP) was increased from 80 +/- 2 to a maximum of 121 +/- 5 mmHg (1 mmHg = 133.3 Pa) in nonpregnant ewes (p < 0.01) and from 79 +/- 2 to 116 +/- 4 mmHg in pregnant ewes (p < 0.01) over the range of AngII infusion. MAP was unaltered during AngII plus nitroprusside infusion, averaging 78 +/- 3 mmHg in nonpregnant ewes and 80 +/- 2 mmHg in pregnant ewes. Basal ANF was higher (p < 0.01) in pregnant sheep than in nonpregnant sheep. With AngII infusion alone, plasma ANF was increased from 13 +/- 2 to 42 +/- 4 fmol/microL in nonpregnant ewes (p < 0.01) and from 23 +/- 5 to 72 +/- 16 fmol/microL in pregnant ewes (p < 0.01). However, during AngII plus nitroprusside infusion, the increases in plasma ANF observed were completely abolished in both nonpregnant and pregnant ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

Real-time monitoring of the gas phase reactions of a single ion population using the remeasurement experiment in Fourier transform ion cyclotron resonance mass spectrometry

A single population of multiply charged protein ions formed by electrospray ionization is held in a trapped ion cell and remeasured continuously by Fourier transform ion cyclotron resonance (FTICR) mass spectrometry while undergoing multiple reactions with diethylamine. In a first example, electrosprayed horse myoglobin with an average of 16 attached protons is reacted with base at a pressure of 1.5 x 10(-8) Torr for a period of 60 s. A total of 31 spectra acquired with a duty cycle of 2 s exhibit the charge state-dependent formation of up to three diethylamine adducts and removal of up to nine protons. A realtime measuring experiment is then conducted over a 1 h period to observe charge stripping of electrosprayed myoglobin ions, leaving as few as seven charges. Realtime monitoring is used to evaluate the effect of reagent gas pressure on adduct formation and is used in conjunction with high mass resolution FTICR detection to resolve the isotopic peaks within individual charge states of adduct spectra. The attractive features of real-time reaction monitoring include a dramatic reduction in experiment time and sample consumed while concurrently observing long-lived intermediates and reaction products as they form.

[The effect of retinoic acid on DNA synthesis of fibroblast in vitro culture]

The effect of retinoic acid on DNA synthesis of fibroblast was studied in vitro culture. The results demonstrated that retinoic acid significantly (P < 0.01) inhibited the DNA synthesis of fibroblast in vitro culture and a dose-dependent relationship between DNA synthesis and retinoic acid concentration was observed. The possible mechanism of retinoic acid used for the treatment of scar was discussed.

Staurosporine affects calcium homeostasis in cultured bovine adrenal chromaffin cells

These studies show that the potent, non-specific, protein kinase inhibitor, staurosporine, disrupts Ca2+ homeostasis in cultured bovine adrenal chromaffin cells. Staurosporine treatment reduces basal and A23187-stimulated catecholamine release from chromaffin cells, but does not inhibit activated Ca2+ influx. Furthermore, pretreatment with staurosporine also reduces Ca(2+)-stimulated catecholamine release from digitonin-permeabilized cells (t1/2, 40.6 min; IC50, 66.0 nm). However, staurosporine does not inhibit the rise in intracellular Ca2+ ([Ca2+]i) in response to nicotine stimulation as measured by fura-2 photometry. These studies demonstrate that staurosporine interferes with the secretory process at some step at or after the rise in [Ca2+]i in adrenal chromaffin cells. Examination of the effects of staurosporine on 45Ca2+ movement shows that staurosporine produces a slowly developing basal 45Ca2+ accumulation; after 30 min no significant change is observed, but by 120 min, 45Ca2+ accumulation is increased by 29.5%. Thapsigargin and 2,5-di-(tert-butyl)-1,4-benzohydroquinone (tBHQ), inhibitors of Ca(2+) ATPases, were used to determine whether staurosporine induced 45Ca2+ accumulation results from sequestration of 45Ca2+ within intracellular stores. While thapsigargin has no significant effect, concomitant treatment with tBHQ prevents the increase in 45Ca2+ uptake associated with staurosporine treatment. Therefore, the tBHQ-sensitive Ca2+ store, but not the thapsigargin/inositol 1,4,5-triphosphate-sensitive Ca2+ store, appears to be staurosporine-sensitive. Overall, these studies indicate that staurosporine reduces catecholamine release by interfering with Ca2+ homeostasis. Furthermore, this work suggests that a staurosporine-sensitive phosphoprotein(s) is involved with the regulation of Ca2+ homeostasis in bovine adrenal chromaffin cells.

Cell geometry considerations for the Fourier transform ion cyclotron resonance mass spectrometry remeasurement experiment

Three cell geometries, closed cubic, closed elongated, and open elongated, are evaluated for optimum remeasurement performance in the Fourier transform ion cyclotron resonance mass spectrometry (FTICR) experiment. The advantages and disadvantages of each cell during normal FTICR operation are discussed. Unit remeasurement efficiency is obtained for the closed elongated cell at approximately 71% of the cell radius, whereas the open elongated cell achieves unit remeasurement at only approximately 18% of the cell radius. The closed cubic cell does not achieve unit remeasurement efficiency at a detectable signal level. A correlation between remeasurement efficiency and the characteristic radial electric field of each trapped ion cell is established. Radial dispersion of the ion cloud is considered the dominant signal loss mechanism in the remeasurement experiment, and cell geometries are examined for optimized sensitivity and unit remeasurement efficiency.

[Herpes zoster keratoendotheliitis]

Herpes zoster keratoendotheliitis is related to autoimmunity or herpes zoster virus infection. It is characterised by K.P. and interstitial edema. The disease responds well to the administration of steroids and a good result is often achieved.

The effects of gonadotropin on the phosphatidylinositol pathway in the primate corpus luteum

The current study was designed to investigate the effects of gonadotropin on basal and prostaglandin (PG) F2 alpha-induced activity of the phosphatidylinositol pathway in corpora lutea (CL) of rhesus monkeys. Luteal progesterone production in vitro was significantly stimulated (P < 0.05) by human chorionic gonadotropin (hCG). Neither basal nor PGF2 alpha-induced phosphatidylinositol 4,5-bisphosphate hydrolysis was significantly influenced by hCG in CL of various ages (P > 0.10). Gonadotropin did induce a slight, yet sustained, increase (P < 0.05) in [Ca2+]i in approximately 70% of luteal cells. The maximal increase in [Ca2+]i in response to hCG (approximately 100 nM) was about one-tenth that induced by PGF2 alpha (approximately 1000 nM). hCG treatment did not alter (P > 0.10) the increase in [Ca2+]i induced by PGF2 alpha Treatment-induced changes in [Ca2+]i did not differ between small (17-21 microns) and large (23-28 microns) luteal cells. Therefore, luteolytic agents are more potent activators of the phosphatidylinositol pathway than luteotropins. This is consistent with the hypothesis that the phosphatidylinositol pathway is involved in primate luteal regression. The inability of hCG to acutely alter the responsiveness of this pathway to PGF2 alpha suggests that CG may rescue the CL of early pregnancy via a mechanism other than direct inhibition of the luteolytic actions of PGF2 alpha.

Selective generation of charge-cependent/independent ion energy distributions from a heated capillary electrospray source

Retarding grid and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry variable trap potential measurements are performed to determine factors that contribute to the kinetic energy distribution of ions formed in an electrospray source that uses a heated capillary for desolvation. The control of ion kinetic energies is achieved by manipulating the skimmer position in the postcapillary expansion and by varying the potential appEed to the skimmer. The selective generation of either charge-dependent or charge-independent ion energy distributions is demonstrated. Charge-dependent energy distributions of electro-sprayed ions are created by sampling ions near the Mach disk of the supersonic expansion and by using a larger diameter skimmer orifice; the FTICR spectra acquired under these conditions exhibit mass-to-charge ratio-dependent mass discrimination determined by the potential used to trap the ions. Charge-independent energies of electrosprayed ions are created by positioning the capillary adjacent to the skimmer to sample thermal ions and by using a smaller skimmer orifice to reduce expansion cooling; under these conditions ion kinetic energy is determined primarily by the skimmer potential and no mass-to-charge ratio-dependence is observed in the selection of optimum FTICR trapping conditions. The ability to select between proteins of different conformation on the basis of kinetic energy differences is demonstrated. For example, a 0.4 V difference in trap potential is observed in the selective trapping of open and closed forms of the +10 charge state of lysozyme. Finally, it is demonstrated that by operating the source under conditions which deliver a beam of ions with charge-independent energies to the cell, it is possible to obtain precursor and product ion signal magnitudes in FTTCR spectra without charge-dependent mass discrimina-tion.

Gastric muscularis as a urinary sphincter

OBJECTIVE

To test the ability of gastric muscularis to act as a urinary sphincter in a rat model system.

METHODS

Fourteen Long-Evans rats had an ileal conduit constructed joining the bladder to the ventral skin, creating urinary incontinence. A segment of gastric muscle maintained on its vascular pedicle was encircled around the conduit. The first 7 animals (group A) had both conduit and sphincter constructed simultaneously, whereas the remaining 7 animals had the conduit constructed first, followed by a two-week period of observation, after which gastric sphincters were added (group B). All animals were observed for urine leakage via the cutaneous stoma. At two weeks after sphincter placement, all animals underwent surgical exploration, pressure profilometry of the conduit, and histologic examination of the sphincter zone.

RESULTS

Pressure profilometry demonstrated elevated pressures in the sphincter zone relative to baseline pressures in the conduit of all animals (group A: mean baseline, 4.8 cm water, mean maximum, 20.6 cm water; group B: mean baseline, 5.2 cm water, mean maximum, 18.1 cm water). At exploration, no intra-abdominal complications were noted in 13 of 14 animals. All conduits were easily catheterizeable and were found to be continent after they had been filled to capacity. The ileum and gastric segments were histologically found to be viable with no evidence of necrosis or ischemia.

CONCLUSIONS

These preliminary results suggest that gastric muscularis may be a potential substitute urinary sphincter in the management of sphincteric urinary incontinence.