Peritoneal dialysis impairs nitric oxide homeostasis and may predispose infants with low systolic blood pressure to cerebral ischemia

BACKGROUND & PURPOSE

Infants on chronic peritoneal dialysis (PD) have an increased risk of developing neurological morbidities; however, the underlying biological mechanisms are poorly understood. In this clinical study, we investigated whether PD-mediated impairment of nitric oxide (NO) bioavailability and signaling, in patients with persistently low systolic blood pressure (SBP), can explain the occurrence of cerebral ischemia.

METHODS & RESULTS

Repeated blood pressure measurements, serial neuroimaging studies, and investigations of systemic nitrate and nitrite levels, as well as NO signaling, were performed in ten pediatric patients on PD. We consistently observed the loss of both inorganic nitrate (-17 ± 3%, P < 0.05) and nitrite (-34 ± 4%, P < 0.05) during PD, which may result in impairment of the nitrate-nitrite-NO pathway. Indeed, PD was associated with significant reduction of cyclic guanosine monophosphate levels (-59.4 ± 15%, P < 0.05). This reduction in NO signaling was partly prevented by using a commercially available PD solution supplemented with l-arginine. Although PD compromised nitrate-nitrite-NO signaling in all cases, only infants with persistently low SBP developed ischemic cerebral complications.

CONCLUSIONS

Our data suggests that PD impairs NO homeostasis and predisposes infants with persistently low SBP to cerebral ischemia. These findings improve current understanding of the pathogenesis of infantile cerebral ischemia induced by PD and may lead to the new treatment strategies to reduce neurological morbidities.

Complement Interactions with Blood Cells, Endothelial Cells and Microvesicles in Thrombotic and Inflammatory Conditions

The complement system is activated in the vasculature during thrombotic and inflammatory conditions. Activation may be associated with chronic inflammation on the endothelial surface leading to complement deposition. Complement mutations allow uninhibited complement activation to occur on platelets, neutrophils, monocytes, and aggregates thereof, as well as on red blood cells and endothelial cells. Furthermore, complement activation on the cells leads to the shedding of cell derived-microvesicles that may express complement and tissue factor thus promoting inflammation and thrombosis. Complement deposition on red blood cells triggers hemolysis and the release of red blood cell-derived microvesicles that are prothrombotic. Microvesicles are small membrane vesicles ranging from 0.1 to 1 μm, shed by cells during activation, injury and/or apoptosis that express components of the parent cell. Microvesicles are released during inflammatory and vascular conditions. The repertoire of inflammatory markers on endothelial cell-derived microvesicles shed during inflammation is large and includes complement. These circulating microvesicles may reflect the ongoing inflammatory process but may also contribute to its propagation. This overview will describe complement activation on blood and endothelial cells and the release of microvesicles from these cells during hemolytic uremic syndrome, thrombotic thrombocytopenic purpura and vasculitis, clinical conditions associated with enhanced thrombosis and inflammation.

Long-term follow-up of cervical intraepithelial neoplasia treated with minimal conization by carbon dioxide laser

BACKGROUND AND OBJECTIVE

Minimal conization with carbon dioxide laser (CO2) for safe diagnosis and treatment of cervical intraepithelial neoplasia (CIN) 1-3 has been utilized for 15 years. To evaluate the results of 15 years' follow-up.

STUDY DESIGN/MATERIALS AND METHODS

Clinical prospective study: 2,903 non-pregnant women whose cervicovaginal smear revealed CIN 1-3, confirmed by colposcopy, were referred for minimal conization treatment (LMC). This outpatient free-hand excision is performed under local anesthesia with a 60-W continuous laser beam focused to a 0.1-mm spot size, giving a power density of 165,000 W/cm2. Adjuvant cervical curettage is done routinely.

RESULTS

Complications after the procedure were insignificant. Histopathological investigations revealed invasive carcinoma in 1.2% of the minicones. The primary cure rate was 96.1%. In the life table analysis of the patients the cumulative risk of recurrence for all forms of CIN was 0.89% at year 5, 1.36% at year 10, and 3.02% at year 15. There was no sudden onset carcinoma during the follow-up period.

CONCLUSION

Minimal conization is a safe, effective treatment for CIN and early forms of microinvasive carcinoma. Invasive carcinoma can be detected early and should be treated without delay. The cumulative risk of developing new CIN is 3.02% at year 15 and there is no risk of sudden-onset invasive carcinoma following this procedure.

Laser miniconization procedure

OBJECTIVE

To describe the outpatient procedure of minimal conization with free-hand guided high power density carbon dioxide laser for simultaneous diagnosis and treatment of CIN producing a one-piece tissue specimen for histological examination.

MATERIAL AND METHODS

3100 non-pregnant patients with mild, moderate or severe dysplasia in pap smear, having colposcopically proved ectocervical lesions but without evidence of invasive carcinoma, or 85 pregnant patients with severe dysplasia in pap smear having extensive colposcopic signs of at least carcinoma in situ were admitted for this treatment. This outpatient procedure including cervical curettage is performed under local anesthesia to excise a one-piece 5 mm (during pregnancy 7 mm) deep minicone.

RESULTS

The degree of patient discomfort, bleeding complications, postoperative pain, infection or vaginal discharge were all minimal. The procedure was fast, causing minimal thermal damage of resection lines of the minicone specimen. Histopathological examination of the non-pregnant minicones revealed microinvasive or invasive carcinoma in 1.2%, the primary cure rate was 96.1%. During pregnancy, 13.3% malignancy was found. No unexpected sudden onset of invasive carcinoma was recorded during the 15-year follow-up and the cumulative risk of recurrence for all forms of CIN was 3.02%

CONCLUSIONS

The outpatient miniconization procedure, performed with a free-hand guided 60-W high power density CO2 laser is a reliable method for simultaneous diagnosis and treatment of CIN. Because of the paucity of complications, this procedure may also be appropriate during pregnancy.

Laser "miniconisation' and the outcome of subsequent pregnancy

We routinely use the carbon dioxide laser miniconisation procedure for cervical interepithelial neoplasia I-III. A retrospective case control study was conducted in 1,485 miniconised women during 250 subsequent pregnancies (including three twin pregnancies). The analysis showed that the miniconised subjects had no significant pregnancy complications and the same preterm birth ratio (8.0%) as controls matched for age and parity.

Carbon dioxide laser miniconization for treatment of human papillomavirus infection associated with cervical intraepithelial neoplasia

BACKGROUND

The effect of the carbon dioxide laser miniconization for treatment of cervical intraepithelial neoplasia with concomitant human papillomavirus infection was evaluated.

MATERIAL AND METHODS

One hundred and eighteen women with cytologically proven cervical intraepithelial neoplasia stage 1 and/or 2 were investigated with repeat vaginal smear, colposcopy and human papillomavirus DNA sampling. Seventy-five out of 118 women were subjected to laser miniconization or punch biopsy and cervical curettage.

RESULTS

Out of 118 patients 37 proved to have positive human papillomavirus DNA with one or more oncogenic types (31.4%). Of these, 32 women were miniconized and five subjected to punch biopsy or cervical curettage. On the first follow-up after miniconization all 32 patients were HPV negative. With follow-up up to five years no recurrences of HPV or dysplasia were seen.

CONCLUSION

A miniconization procedure with carbon dioxide laser for treatment of cervical intraepithelial neoplasia proved useful also for simultaneous therapy of concomitant human papillomavirus infection of the uterine cervix.

Prevalence of urinary incontinence in middle-aged women

An anonymous questionnaire was used to interview 946 premenopausal women (age 29-52 years), previously either hysterectomized or laparoscopically sterilized, concerning disorders of the urinary tract. Of the 750 (79.3%) women that responded, 307 (40.9%) admitted to some degree of urinary disorder. The prevalence of urinary disorders was 170/415 (40.9%) for the women with a previous supravaginal or total hysterectomy and 137/335 (40.8%) for the women in the sterilization group. Of the responding women 85 (11.3%) experienced a urinary loss sufficient to necessitate the wearing of a sanitary napkin or change of underclothing several times a day.

Carbon dioxide laser vaporization of plaque psoriasis

The treatment of circumscribed plaque psoriasis with a carbon dioxide (CO2) laser as an outpatient procedure is reported in three patients. The growth of new tissue over the healed laser vaporized area was similar to normal skin and has remained free of psoriasis during a follow-up of 3 X 5 years. Laser vaporization appears to be a simple and effective alternative to conventional therapy in cases of plaque psoriasis.