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Biomedical subjects

S M Katz

Publications and source records attributed to S M Katz.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of tacrolimus on hemodynamics and absorption of experimental small intestinal transplants.

We have previously reported the adverse effects of cyclosporine on small intestine transplant physiology. In this study, we report for the first time the effect of tacrolimus (FK) on graft intestinal blood flow and intramural distribution, vascular resistance, and absorptive function. Isogeneic small intestine transplantation was performed in Lewis rats. Animals were grouped based upon the following treatment schedules: no treatment for 1 week in group 1; 0.6 ml/kg/day i.m. polyethylene glycol (PEG) for 1 week in group 2; 2 mg/kg/day i.m. FK for 1 week in group 3; 0.6 ml/kg/day PEG for 1 week and then 0.3 ml/kg/day for 5 weeks in group 4; 2 mg/kg/day FK for 1 week and then 1 mg/kg/day for 5 weeks in group 5. Group 6 was the same as in group 5 but FK was withdrawn for 1 week prior to assessment. Maltose absorption was measured to evaluate graft absorptive function. Blood flow and its intramural distribution to mucosal and serosal/muscularis layers were determined using the radioactive microsphere technique. Perfusion pressure was measured to calculate vascular resistance. One week of FK administration in group 3 did not change graft hemodynamics and absorption significantly. Prolonged FK treatment up to 6 weeks in group 5 resulted in a significant increase in mucosal vascular resistance (71.0 +/- 9.6 versus 47.7 +/- 6.7 U/g, P<0.01) and significant decreases in mucosal blood flow (1.14 +/- O.15 versus 1.69 +/- 0.24 ml/g/min, P<0.01) and maltose absorption (30 min after loading. 155.4 +/- 26.9 versus 216.4 +/- 29.6, P<0.01; 60 min after loading: 172.9 +/- 24.5 versus 229.1 +/- 32.6 glucose mg/dl P<0.01). The serosal/muscularis layer remained relatively unaffected. Withdrawal of FK for 1 week after prolonged treatment in group 6 resulted in restorations of all parameters measured to normal ranges. We conclude that a short course of FK is safe, but prolonged FK administration has harmful effects on the hemodynamics and function of small intestinal transplants. Complete recovery is achieved when FK is discontinued.

Animals↗
PubMed1996

The impact of elevated serum IgA and race on primary recipient renal allograft survival.

This study correlated overall serum IgA levels in pretransplant (preTx) sera with graft survival. IgA levels, determined by nephelometry, were normally distributed, with a mean level of 255 +/- 139 mg/dl and a median of 234 mg/dl in 631 adult primary kidney allograft recipients and a mean level of 213 +/- 123 mg/dl with a median of 196 mg/dl for 100 retransplant recipients. Improved 3-year survival was associated with a high preTx IgA serum level in primary recipients (Kaplan-Meier analysis, P = 0.01), but not in retransplant patients. After stratifying by race, IgA correlated with graft survival in Caucasian, Hispanic, and "other" (Middle Eastern, Indian subcontinent, and Asian) primary recipients (P < or = 0.04), but not in African Americans. Higher survival rates were not associated with IgA in primary recipients stratified for rejection episodes, blood transfusions, or HLA-DR mismatches. Graft survival was improved in patients with > 2 HLA-AB mismatches and serum IgA above the median. PreTx IgA level and IgA alpha-HLA activity were significantly associated in preTx sera of primary renal allograft recipients (chi 2 = 7.145, P = 0.01), although only 9% (12/133) of sera tested displayed IgA anti-HLA class I reactivity. Thus, enhanced graft survival mediated by elevated serum IgA levels may due in part to competition for allograft HLA class I binding with deleterious Ig subclasses or immune effector cells. Elevated serum IgA may also reflect an altered immunoregulatory state. The results suggest that, depending on the racial group, preTx serum IgA levels are a prognostic indicator of graft survival in primary renal allograft recipients.

Adult↗
PubMed1996

Oral cyclosporine preparations immediately following renal transplantation.

A cohort of 11 patients receiving de novo CyA-GC was compared to 11 patients receiving CyA-ME immediately following renal transplantation at five-dose intervals in the first 30 postoperative days. Neither group achieved target CyA concentrations during days 0 to 2, suggesting that additional immunosuppression exposure coverage may be needed at that interval. Thereafter, however, recipients of the CyA microemulsion (Neoral) formulation reached target levels earlier as well as required lower doses to reach target levels.

Administration, Oral↗
PubMed1995

Improved small intestinal preservation after lazaroid U74389G treatment and cold storage in University of Wisconsin solution.

The small intestine (SI) is highly sensitive to oxygen free radical-induced injury. The most common preservation solution, University of Wisconsin (UW) solution, does not adequately prevent free radical-induced injury. Lazaroids, and U74389G in particular, are a new class of compound that are potent inhibitors of superoxide-mediated lipid peroxidation. We studied the added influence of U74389G to 18-hr cold preservation of rat SI in UW solution. Three groups of rats were studied. In group 1, SI was excised and reperfused immediately. In group 2, SI was stored in UW solution at 4 degrees C for 18 hr. In group 3, U74389G was given to the SI graft before storage and again before reperfusion. Blood reperfusion of the grafts was achieved via connection to the superior mesenteric artery and portal vein of support rats. Functional recovery was assessed using a maltose tolerance test. Weight changes were calculated and histologic studies done. After 30 and 60 min of reperfusion, maltose uptake in group 3 was significantly better than that of the group 2, and returned to control levels. Significantly more tissue swelling was noted in group 3 over control, but the magnitude was less than that of group 2. Less transmural necrosis and villous blunting were noted in group 3 versus group 2; the appearance of the mucosa in group 3 approached that of group 1. We conclude that the use of U74389G treatment in addition to cold storage in UW solution improves recovery of graft function and minimizes morphologic damage to the small intestinal mucosa.

Adenosine↗
PubMed1995

The impact on behavior of notifying methadone patients of their HIV serostatus.

Questions have arisen about the implications of notifying drug abusers of their HIV serostatus. One major concern is that awareness of HIV infection would have a negative impact on abstinence from drug abuse. In order to ascertain the effects of serostatus notification, the authors reviewed the clinical records of 73 methadone patients who learned of their serostatus within 20 weeks after enrolling in the clinic and thereafter remained in treatment for at least 1 year. They found that, at serostatus notification, seropositive patients were more likely to be socially disadvantaged and were younger than the seronegatives at first opiate use. After serostatus notification, seropositives had more "fair hearings" for noncompliance with program norms and used more cocaine. Although the patients notified of HIV infection may have more behavioral problems, further research is needed to determine whether or not this reflects antecedent behavior patterns and drug use.

Adult↗
PubMed1995

The eccentricity effect: target eccentricity affects performance on conjunction searches.

The serial pattern found for conjunction visual-search tasks has been attributed to covert attentional shifts, even though the possible contributions of target location have not been considered. To investigate the effect of target location on orientation x color conjunction searches, the target's duration and its position in the display were manipulated. The display was present either until observers responded (Experiment 1), for 104 msec (Experiment 2), or for 62 msec (Experiment 3). Target eccentricity critically affected performance: A pronounced eccentricity effect was very similar for all three experiments; as eccentricity increased, reaction times and errors increased gradually. Furthermore, the set-size effect became more pronounced as target eccentricity increased, and the extent of the eccentricity effect increased for larger set sizes. In addition, according to stepwise regressions, target eccentricity as well as its interaction with set size were good predictors of performance. We suggest that these findings could be explained by spatial-resolution and lateral-inhibition factors. The serial self-terminating hypothesis for orientation x color conjunction searches was evaluated and rejected. We compared the eccentricity effect as well as the extent of the orientation asymmetry in these three conjunction experiments with those found in feature experiments (Carrasco & Katz, 1992). The roles of eye movements, spatial resolution, and covert attention in the eccentricity effect, as well as their implications, are discussed.

Adult↗
PubMed1995

The accuracy of children's reports with anatomically correct dolls.

The accuracy of children's reports of alleged sexual abuse during interviews with anatomically correct dolls is the focus of considerable controversy. This study used an analog experience to measure empirically the accuracy of reports in a relevant, but controlled setting: the forensic medical examination for suspected sexual abuse. Twenty-one 3- to 7-year-old children were interviewed about what occurred during previous examinations with open-ended questions, open-ended questions with anatomically correct dolls, and direct questions with the dolls. Children provided significantly more accurate reports and fewer omissions with direct questions using the dolls compared with either of the two open-ended sections, but there was no significant difference in the number of false reports across the three sections of the interview. These results suggest that anatomically correct dolls may bolster the recall of children's memory in the setting of direct questions without prompting false reports.

Anatomy↗
PubMed1994

Positive pretransplant crossmatches predict early graft loss in liver allograft recipients.

We evaluated the influence of donor-recipient HLA compatibility and recipient pretransplant antidonor sensitization on liver allograft recipient survival. The overall graft survival results for 67 cyclosporine-prednisone treated liver allograft recipients at 3, 6, and 12 months posttransplant were 86%, 83%, and 83%, respectively. No significant differences were observed when comparing the one-year survivals of 81% vs. 85% for men and women or 80% vs. 85% for adult and pediatric patients. Similarly, no differences were observed when comparing one-year graft survivals for well vs. poorly matched recipients of 77% vs. 83% for recipients with < or = 2 HLA A, B vs. > 2 HLA A, B mismatches (MMs) and 82% vs. 82% for recipients with 0-1 HLA-DR MMs vs. 2 HLA-DR MMs, respectively. Pretransplant transfusion history and race also did not influence survival. Standard NIH (long-incubation) and anti-human globulin (AHG) crossmatches were performed. The 12% of recipients (8/67) displaying a positive NIH crossmatch experienced significantly poorer 3-, 6-, and 12-month survivals of 62% vs. 89%, 62% vs. 86%, and 62% vs. 86% (all P < 0.05), respectively, than the 59 NIH-crossmatch negative recipients. Similarly, the 16% (11/67) of recipients displaying a positive AHG crossmatch had significantly poorer 3-, 6-, and 12-month survivals of 63% vs. 91%, 54% vs. 89%, and 54% vs. 89% (all P < 0.05) respectively, than the 56 AHG crossmatch-negative recipients. NIH and AHG crossmatch-positive sera were treated with dithioerythritol (DTE) to establish whether reactivity was due to IgM or IgG immunoglobulin. One-year graft survivals of 65% vs. 30% (P < 0.05) were observed when the crossmatch-positive sera reactivities were due to IgM vs. IgG immunoglobulin. While graft survivals were improved when positive crossmatch serum reactivity was due to IgM, these survivals were still significantly poorer than when the crossmatches were completely negative (86% vs. 60%, P < 0.05 for NIH-negative vs. NIH-positive, but DTE-negative, and 88% vs. 77%, P < 0.05 for AHG-negative vs. AHG-positive, but DTE-negative). Therefore, an NIH- or AHG-positive crossmatch, due either to IgM or IgG reactivity, results in poor early (3- and 6-months) liver allograft survival. Crossmatch-positive recipients experienced significantly (P < 0.05) more rejections and more steroid-resistant rejections (P < 0.05) than crossmatch-negative recipients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1994

Prolonged use of cyclosporine (CsA) produces reversible hemodynamic and absorptive alterations in the transplanted rat small intestine.

Cyclosporine (CsA)-induced alterations in organ blood flow (BF) and function have been studied in kidney and pancreatic transplants. In this study, we assessed the effect of prolonged CsA administration on graft tissue BF and absorption from transplanted rat small intestine (SI). Isogeneic SI transplantation was performed in Lewis rats. Animals were grouped based upon the following treatment schedules: no treatment for 1 week in group 1; 0.15 ml/kg/day im olive oil for 1 week in group 2; 0.15 ml/kg/day olive oil for 1 week and then 0.1 ml/kg/day for 5 weeks in group 3; 15 mg/kg/day im CsA for 1 week in group 4; and 15 mg/kg/day CsA for 1 week and then 10 mg/kg/day for 5 weeks in group 5. Group 6 was the same as group 5 but CsA was withdrawn for 1 week prior to assessment. Maltose absorption was measured to evaluate graft absorptive function. BF and its intramural distribution to mucosal and serosal/muscularis layers were determined using the radioactive microsphere technique. Perfusion pressure was measured to calculate vascular resistance (VR). One week of CsA of administration in group 4 resulted in a significant increase in mucosal VR (68.4 +/- 15.5 versus 46.9 +/- 8.7 U/g, P < 0.01) and significant decreases in mucosal BF (1.21 +/- 0.25 versus 1.80 +/- 0.38 ml/g/min, P < 0.01) and maltose absorption 30 min after loading (168.9 +/- 21.1 versus 214.4 +/- 28.4 glucose mg/dl, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Liver transplantation. The last ten years.

8960741 10 years have witnessed a number of changes in the liver transplant process. Key among these changes are the longer preservation times allowed with UW solution, the development of the new techniques for the transplantation of pediatric patients, and the reintroduction of xenotransplantation for both permanent and temporary hepatic support. Early referral and prompt transplant of patients are among the most important keys to successful transplantation. However, owing to the present organ allocation system and the lack of suitable organ donors, potential liver transplant recipients will continue to experience a significant mortality rate on the waiting list. In addition, owing to the long waiting times for suitable donor organs, many patients who would have been excellent low-risk candidates will deteriorate as their liver disease progresses and become high-risk patients for liver transplantation. Expanding the donor pool and modifying the present liver allocation system to shift the flow of organs to the better-risk patients will do more to improve the results of liver transplantation than any other change in the management and transplantation of patients with severe liver disease.

Actuarial Analysis↗
PubMed1994

Surgical complications of liver transplantation.

Surgical complications remain a frequent cause of morbidity after liver transplantation. A high index of suspicion, aggressive diagnostic testing, and a low threshold for re-exploration are necessary to ensure early treatment of these complications.

Biliary Tract Diseases↗
PubMed1994

Special considerations in the transplant patient requiring other surgery.

The surgeon planning an operation on a transplant patient should regard the undertaking with healthy respect but not with fear. Immunosuppressive agents alter the patient's response to surgical stress and slow healing. The immunosuppressed state increases the patient's susceptibility to infection. For these reasons, certain precautions must be taken. But a careful surgeon can bring a transplant patient successfully through necessary surgery.

Humans↗
PubMed1994

Pediatric living-related and cadaveric liver transplantation: a single center experience.

Living-related liver transplantation is becoming more commonplace worldwide in the treatment of end-stage liver disease in the pediatric age group. Our LRD experience has resulted in patient and graft survival rates comparable to our cadaveric donor recipients. The incidence and severity of acute rejection episodes were similar. This differs from the clear immunologic advantage of living-related donation in kidney transplantation. It may, however, reflect the relatively small numbers in our LRD group. Overall, however, the technical complications are manageable with early intervention, yielding acceptable results.

Adult↗
PubMed1993

Diagnostic value of electron microscopy on paraffin-embedded cytologic material.

Transmission electron microscopy (TEM) is an important adjuvant to light microscopy, but is underutilized in cytopathology because of technical obstacles. One should attempt to obtain properly fixed material for TEM whenever possible. If that is not available, TEM on the cell block requires no preplanning or additional needle passes, and avoids problems of inadequate tissue for diagnosis. However, cell blocks are often not examined because of the perception that their poor ultrastructural preservation precludes their utility. We describe our experience in performing TEM on cell blocks from 15 cytologic specimens. In 13 of 15 cases, the cell block material was adequate for ultrastructural evaluation, and it clarified or extended the diagnosis in seven of these cases. TEM is a useful adjuvant technique to cytodiagnosis and can be successfully performed on cell blocks when gluteraldehyde-fixed material is not available.

Adenocarcinoma↗