Measurement of the force and torque produced in the calcium response of reactivated rat sperm flagella.

Rat sperm that are demembranated with Triton X-100 and reactivated with Mg-ATP show a strong mechanical response to the presence of free calcium ion. At pCa < 4, the midpiece region of the flagellum develops a strong and sustained curvature that gives the cell the overall appearance of a fishhook [Lindemann and Goltz, 1988: Cell Motil. Cytoskeleton 10:420-431]. In the present study, the force and torque that maintain the calcium-induced hook have been examined quantitatively. In addition, full-length and shortened flagella were manipulated to evaluate the plasticity of the hooks and determined the critical length necessary for maintaining the curvature. The hooks were found to be highly resilient, returning to their original configuration (>95%) after being straightened and released. The results from manipulating the shortened flagella suggest that the force holding the hook in the curved configuration is generated in the basal 60 microm of the flagellum. The force required to straighten the calcium-induced hooks was measured with force-calibrated glass microprobes, and the bending torque was calculated from the measured force. The force and torque required to straighten the flagellum were found to be proportional to the change in curvature of the hooked region of the flagellum, suggesting an elastic-like behavior. The average torque to open the hooks to a straight position was 2.6 (+/-1.4) x 10(-7) dyne x cm (2.6 x 10(-14) N x m) and the apparent stiffness was 4.3 (+/-1.3) x 10(-10) dyne x cm(2) (4.3 x 10(-19) N x m(2)). The stiffness of the hook was determined to be approximately one quarter the rigor stiffness of a rat sperm flagellum measured under comparable conditions.

Report from the national transplantation pregnancy registry (NTPR): outcomes of pregnancy after transplantation.

The NTPR continues to analyze the safety of pregnancy in female transplant recipients as well as outcomes of pregnancies fathered by male transplant recipients. With regard to female recipients, pregnancy does not appear to adversely affect graft function, when the function of the transplanted graft is stable prior to pregnancy. A small percentage of recipients with each transplanted organ develops rejection, graft dysfunction or graft loss. These events may occur in recipients with pre-pregnancy graft dysfunction or on occasion, occur unpredictably. Female cyclosporine-treated kidney recipients with both shorter and longer intervals from transplant to conception have been analyzed, with favorable outcomes noted. It appears sensible to continue to advise recipients to wait one to 2 years after transplant to allow for stable graft function as well as stabilization of immunosuppressive medications. However, given that favorable outcomes can occur with either shorter or longer intervals, these recipients need to be counseled and followed on a case-by-case basis. Newer agents and more potent regimens are under continued surveillance. Two cases with structural malformations have been noted in female recipient offspring with exposure to MMF during pregnancy. Data remain limited and are insufficient to determine a specific malformation incidence. The risk of graft rejection as well as graft dysfunction must be weighed against the risk of potential teratogenicity when maintaining female recipients on MMF during pregnancy. For male recipients maintained on MMF, there have been no patterns of problems noted in their offspring. The structural malformation incidence in newborn of cyclosporine-treated recipients is in the range expected for the general population without any specific predominance of malformations. It remains to be seen whether or not any specific pattern of problems will become apparent in the newborn with newer regimens. Controversy surrounding breastfeeding continues, although it has become an option that some recipients choose to consider. Data have accrued in liver, heart, pancreas-kidney and lung recipients. Among lung recipients, there appears to be poorer maternal survival postpartum, which may be related to pregnancy or may be inherent in this population. Continued entries to the registry, especially in light of newer combinations of immunosuppressive agents, should help to provide the guidelines for management. All centers are encouraged to participate.

Results of liver transplantation for nodular regenerative hyperplasia.

Liver transplantation has been performed in individuals with a pretransplant clinical diagnosis of cirrhosis but with nodular regenerative hyperplasia histologically. The purpose of this report is to investigate the results of liver transplantation in patients proven to have nodular regenerative hyperplasia post-transplant. A retrospective review was undertaken of four patients who underwent liver transplantation with a histologic diagnosis of nodular regenerative hyperplasia. All were felt to be cirrhotic on clinical grounds. Final histology of the explanted liver was confirmed by a single pathologist. Their ages ranged from 39 to 54 years, and three of the four were male. Three had pretransplant needle liver biopsies, two percutaneous and one transjugular. All revealed nonspecific reactive changes. Ultrasound and MRI were interpreted as consistent with cirrhosis in four of four and three of four cases, respectively. Portal vein flow was hepatopedal in three and absent in one. Pretransplant clinical characteristics and frequency were as follows: bleeding varices two, clinical ascites three, encephalopathy three, and impaired hepatic synthetic function two. All four patients underwent successful liver transplantation. There were no episodes of acute rejection. All are alive and well with normal graft function 2 to 4 years post-transplant. We conclude the following. 1) Patients with clinical end-stage liver disease due to underlying nodular regenerative hyperplasia can successfully undergo transplantation. 2) Nodular regenerative hyperplasia can present with signs and symptoms of liver failure, is difficult to diagnose by needle biopsy, and can be difficult to discriminate clinically from cirrhosis. 3) Although each case must be individually evaluated transplantation may be the optimal therapy in patients presenting with complications of liver failure.

Pregnancy after liver transplantation.

The first known posttransplantation pregnancy was in 1958 in a renal transplant recipient who had received a kidney from her identical twin sister. The first known posttransplantation pregnancy in a liver transplant recipient was in 1978. Information available from female kidney transplant recipients helped in the decision making involved in the management of this case, as well as those that followed. Over the last 20 years, issues specific to liver transplantation and pregnancy have been identified. Similar to the kidney transplant recipient population, when prepregnancy recipient graft function is stable and adequate, pregnancy appears to be well tolerated. Also similar to kidney transplant recipients, there has been no evidence of a specific malformation pattern among the children, and although prematurity and low birth weight occur, overall newborn outcomes have been favorable. Pregnancy in the setting of recurrent liver disease, such as recurrent hepatitis C, poses a potential problem among liver transplant recipients, as well as the possible adverse effects of immunosuppression on maternal kidney function. Also of significance, peripartum graft deterioration has more severe consequences in this transplant recipient population. Therefore, pregnancy must be considered carefully in this transplant recipient group. Since 1991, the National Transplantation Pregnancy Registry (NTPR) has studied the safety of pregnancy outcomes in solid-organ transplant recipients. The purpose of this review is to catalog studies in the literature, as well as to present current data from the registry with management guidelines.

Preoperative evaluation of living renal donors: comparison of CT angiography and MR angiography.

PURPOSE: To compare computed tomographic (CT) angiography and magnetic resonance (MR) angiography for preoperative evaluation of living renal donors. MATERIALS AND METHODS: Thirty-five living renal donors underwent preoperative contrast material-enhanced CT angiography and gadolinium-enhanced MR angiography. Each study was interpreted by two independent radiologists blinded to all other studies and to interpretations provided by other reviewers. Eighteen kidneys had surgical correlation. RESULTS: CT demonstrated 33 supernumerary arteries in 19 patients, bilateral solitary arteries in 16 patients, and 18 proximal arterial branches in 16 patients. MR demonstrated 26 supernumerary arteries in 15 patients, bilateral solitary renal arteries in 20 patients, and 21 proximal arterial branches in 16 patients. Interobserver agreements for MR (kappa = 0. 74) and CT (kappa = 0.73) were similar to the agreement between MR and CT (kappa = 0.74). Among the kidneys chosen for nephrectomy, one small accessory artery and one proximal arterial branch were missed with CT and MR. Two of the accessory arteries suggested at CT were not found at nephrectomy. By averaging data for both modalities, supernumerary arteries were present in 49% of kidney donors and were bilateral in approximately 17%. Proximal arterial branches were present in 46% of kidney donors. CONCLUSION: Preoperative CT and MR angiography of the renal arteries in renal donors demonstrate substantial agreement. Interobserver disagreement in the interpretation of CT and MR angiograms is related to 1-2-mm-diameter vessels.

Report from the National Transplantation Pregnancy Registry (NTPR): outcomes of pregnancy after transplantation.

Safety of pregnancy in the female transplant recipient population must include consideration of 3 outcomes--mother, baby and transplanted graft. In the majority of female recipients studied, pregnancy does not appear to cause excessive or irreversible problems with graft function, if the function of the transplant organ is stable prior to pregnancy. However, a small percentage of recipients identified within each organ system may develop rejection, graft dysfunction and/or graft loss that may be related to the pregnancy and may occur unpredictably. Outcomes are not entirely similar among all organ systems, and one must consider risks on an individual organ basis. It appears reasonable to advise female recipients to wait one or 2 years after transplantation before attempting pregnancy to insure that function of the transplanted organ is adequate and stable and also to allow for stabilization of immunosuppressive medications. Favorable outcomes, however, have occurred when recipients have become pregnant less than one year from transplant, so cases must be analyzed individually. Immunosuppressive medications may have to be adjusted during pregnancy, and in some cases, rejections occur requiring additional immunosuppressive regimens (steroids and in several cases OKT3). Whether increasing immunosuppressive doses during pregnancy to adjust for falling levels lessens the rejection risk has never been studied prospectively. There is concern based on animal reproductive studies that the risk of birth defects and/or spontaneous miscarriage is increased in women exposed to MMF during pregnancy. Of the 9 pregnancies reported to the registry to date, there have been no birth defects noted among 5 liveborn of female recipients exposed to MMF. Data remain limited. For female recipients, a high incidence of low birth-weight and prematurity compared to the general population has been a consistent outcome, however, there has been no specific pattern of malformation in their newborn or any apparent increase in the incidence of small-for-gestational-age newborn. Long-term follow-up of children to date by the NTPR has been encouraging. A recent report in the literature has suggested impairment of immune function in newborn of CsA-treated mothers. Further study is needed. Some mothers have chosen to breastfeed. The potential risk to the newborn of ingested immunosuppressives compared with the potential benefits of breastfeeding is unknown and options must be discussed with the recipient. From earlier registry reports, recipients with deteriorating graft function, such as liver recipients with recurrent hepatitis C and/or other recipients with deteriorating graft function, appear to be at risk for worsened graft function with pregnancy. Outcomes of male recipient fathered pregnancies have been favorable and appear to be similar to the general population, but this group has not been as well studied as female recipients. No structural problems have been noted in the 38 offspring of males on MMF at the time of conception. Within each organ group, some female recipients have reported more than one pregnancy, sometimes on differing immunosuppressive regimens. If there is stable graft function, additional successful pregnancies are possible. Continued entries to the registry, especially in light of newer immunosuppressives and combinations of agents, are needed to continue to provide guidelines for management. The NTPR acknowledges the cooperation of transplant recipients and over 200 centers nationwide who have contributed their time and information to the registry. The NTPR is supported by grants from Novartis Pharmaceuticals Corp., Fujisawa Healthcare, Inc., Roche Laboratories Inc. and Wyeth-Ayerst Pharmaceuticals, Inc.

Budd-Chiari syndrome complicating restorative proctocolectomy for ulcerative colitis: report of a case.

PURPOSE: This is a case of hepatic vein thrombosis presenting in a delayed fashion after proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis. Search for a causative thrombotic condition resulted in the diagnosis of polycythemia vera, a myeloproliferative disorder associated with hypercoagulability. The polycythemia was masked by an iron deficiency associated with the ulcerative colitis. METHODS: The history, physical, diagnostic modalities, and treatment for this patient are described, and the literature of Budd-Chiari syndrome associated with ulcerative colitis is reviewed. RESULTS: Six cases of Budd-Chiari syndrome in the setting of ulcerative colitis are reported in the literature from 1945 to 1997. CONCLUSIONS: Hepatic vein thrombosis is a rare complication of ulcerative colitis. The diagnosis of Budd-Chiari syndrome demands a thorough search for a hematologic condition predisposing to thrombosis. Our patient had a myeloproliferative disorder, polycythemia vera, that is associated with a hypercoagulable state. The disorder was masked by an iron deficiency associated with the ulcerative colitis. Recognition of the entity will permit successful treatment.

Report from the National Transplantation Pregnancy Registry (NTPR): outcomes of pregnancy after transplantation.

Specific data on pregnancies following transplantation continue to accrue in the National Transplantation Pregnancy Registry (NTPR) in each type of organ recipient, with the following conclusions: 1. While the majority of kidney recipients appear to tolerate pregnancy well, a small percentage develops rejection, graft dysfunction and/or graft deterioration. Overall, there is a slight increase in the mean postpartum creatinine level when compared with the prepregnancy level, which has been noted in previous investigations by the NTPR. One neonatal death attributed to thrombotic cardiomyopathy was noted in a set of twins of a tacrolimus-based kidney recipient, but no other death has been noted in any of the additional reports among the recipients given newer immunosuppression regimens. Follow-up of offspring of these recipients is ongoing. 2. No structural malformations have been noted among offspring exposed to mycophenolate mofetil, but exposures are limited. (5 mothers, 29 fathers). 3. Female liver recipients with biopsy-proven acute rejection during pregnancy appear to be at greater risk for both poorer newborn outcomes and recurrent rejection episodes. In the setting of acute rejection diagnosed during pregnancy, close attention is warranted, anticipating that birthweight may be lower and that a substantial percentage of these female recipients may have recurrent rejection episodes. 4. Pancreas-kidney grafts can maintain normoglycemia throughout pregnancy. A high incidence of maternal hypertension, prematurity and low birthweight have been noted, so, as in other recipient groups, these are high-risk pregnancies. Maternal pancreas and kidney function must be closely monitored. 5. No specific prepregnancy predictors of adverse outcomes have yet been identified among heart or lung recipients although none of the deaths among heart recipients in the NTPR database occurred within 2 years of delivery. When compared with other solid organ recipients, female lung recipients may face higher risks, particularly related to rejection. Whether prepregnancy factors can help to predict either heart or lung recipients at risk requires continued study. 6. No structural malformations or significant learning disabilities have been noted in follow-up of the offspring of CsA-treated females, the largest group of offspring followed to date with a mean age of 4-5 years. Continued surveillance of children will be essential to determine if effects become apparent as age-related developmental delays or other problems in immune function or fertility later in life. 7. Newer regimens as well as new combinations of agents will continue to be studied. It is essential that non-viable as well as viable pregnancy outcomes be reported to the registry (i.e., recipients with pregnancies that result in spontaneous abortion or termination should be included for study). True estimates of non-viable outcomes have been difficult to assess. Additionally, inclusion of reports of pathologic evaluations at delivery hospitals will be helpful to determine whether spontaneous abortions are a result of lethal malformations related to immunosuppressive or other medication exposure. Safety of pregnancy for parent and child remain the primary goals of the NTPR.

Pregnancy outcomes in 10 female pancreas-kidney recipients.

Female recipients of pancreas-kidney transplants may have an increased chance for pregnancy, because transplantation often restores fertility. Data on pregnancy after pancreas-kidney transplantation were analyzed by the National Transplantation Pregnancy Registry at US transplant centers. Ten recipients who were on cyclosporine-based immunosuppression were studied. A total of 15 pregnancies had resulted, of which 12 were live births. Among the 12 newborns, prematurity and low birth weight occurred in 75% and 83% of the cases, respectively. Three had complications associated with prematurity. Two thirds of the infants were delivered by cesarean section. All children are developing well with no apparent residual problems. During pregnancy, hypertension and urinary tract infections occurred frequently among recipients. Two recipients had three subsequent graft losses within 2 years of giving birth; however, both were successfully retransplanted. Successful pregnancy is possible for female pancreas-kidney recipients.

Drug safety issues in pregnancy following transplantation and immunosuppression: effects and outcomes.

Successful pregnancy outcomes are possible after solid organ transplantation. While there are risks to mother and fetus, there has not been an increased incidence of malformations noted in the newborn of the transplant recipient. It is essential that there is closely coordinated care that involves the transplant team and an obstetrician in order to obtain a favourable outcome. Current data from the literature, as well as from reports from the National Transplantation Pregnancy Registry (NTPR), support the concept that immunosuppression be maintained at appropriate levels during pregnancy. At present, most immunosuppressive maintenance regimens include combination therapy, usually cyclosporin or tacrolimus based. Most female transplant recipients will be receiving maintenance therapy prior to and during pregnancy. For some agents, including monoclonal antibodies and mycophenolate mofetil, there is either no animal reproductive information or there are concerns about reproductive safety. The optimal (lowest risk) transplant recipient can be defined by pre-conception criteria which include good transplant graft function, no evidence of rejection, minimum 1 to 2 years post-transplant and no or well controlled hypertension. For these women pregnancy generally proceeds without significant adverse effects on mother and child. It is of note that the epidemiological data available to date on azathioprine-based regimens are favourable in the setting of a category D agent (i.e. one that can cause fetal harm). Thus, there is still much to learn regarding potential toxicities of immunosuppressive agents. The effect of improved immunosuppressive regimens which use newer or more potent (and potentially more toxic) agents will require further study.

Risks of subsequent pregnancies on mother and newborn in female heart transplant recipients.

BACKGROUND: Female heart transplant recipients are able to carry pregnancies successfully. This study evaluates the effect of subsequent pregnancies on newborn and maternal outcomes and graft survival. METHODS: Subjects were identified through a previously reported multicenter study, case reports from literature review, and recipients entered in the National Transplantation Pregnancy Registry. A retrospective analysis was completed of 35 heart transplant recipients with first pregnancies (FP) and 12 who had one or two additional pregnancies (P>1). Newborns were assessed for gestational age, neonatal birth weight, and complications. Maternal data included pregnancy outcome, peripartum complications, including infection and rejection, current graft function, and recipient survival. RESULTS: Forty-seven pregnancies (35 FP and 12 P>1) from 35 heart transplant recipients were studied. FP outcomes included 26 live births (one set of twins), four miscarriages, and six therapeutic abortions, whereas P>1 outcomes included 11 live births (one set of twins), and two miscarriages. There was no significant difference between mean birth weights (2353+/-986 gm vs 2588+/-521 g, P>1 vs FP; mean+/-SD; p=NS) or prematurity incidence (<37 weeks; 50% vs 40%; p=NS) for the live-born infants. Compared with the FP group, there was a trend toward increased neonatal complications in P>1 (40% vs 12%; p=NS). Complications were significantly more common in premature newborns compared with full-term newborns (33% vs 5%; p < 0.05). No structural malformations were identified in the live-born infants. Maternal complication rates were the same in both groups (40%). Of 28 recipients available for follow-up, the maternal survival rate was 75% for the FP group and 89% for the P> group. Mean rejection rate per year was slightly increased after pregnancy in the P>1 group. Surviving recipients had similar graft function by echocardiographic left ventricular ejection fraction. CONCLUSIONS: Post-heart transplantation pregnancies often have successful outcomes, but there is a high incidence of prematurity and low birth weight. Subsequent pregnancies do not seem to significantly increase the incidence of complications in either the newborn or mother or increase graft rejection or failure. Larger studies of posttransplantation pregnancies may provide more definitive information.

Comparison of Doppler US and CT angiography for evaluation of renal artery stenosis.

RATIONALE AND OBJECTIVES: The authors compared Doppler ultrasound (US) with computed tomographic (CT) angiography in the evaluation of stenosis of the main renal artery. MATERIALS AND METHODS: Fifty-six patients who had undergone conventional angiography of the renal arteries participated in a prospective comparison of Doppler US (45 patients) and CT angiography (52 patients). US evaluation included both the main renal artery and segmental renal arteries. RESULTS: There were 27 main renal arteries with at least 50% stenosis in 20 patients. In 36 patients, there was no significant stenosis. All cases of main renal artery stenosis detected with Doppler US of the segmental arteries were also identified with Doppler US of the main renal artery. The by-artery sensitivity (63%) of US of the main renal artery was greater than that (33%) of US of the segmental arteries. CT angiography was more sensitive (96%) than Doppler US (63%) in the detection of stenosis, but the specificity of CT (88%) was similar to that of US (89%). The difference in the area under the receiver operating characteristic curve (AUC) between CT (AUC = 0.94) and US (AUC = 0.82) was statistically significant (P = .038). CONCLUSION: Doppler US of the main renal artery is more sensitive than Doppler US of segmental arteries in the detection of stenosis. CT angiography is more accurate than Doppler US in the evaluation of renal artery stenosis.