Effect of timing of cyclosporine administration on recovery from renal ischemia in rats

The effect of timing of cyclosporine administration on functional recovery from renal ischemia was studied in Sprague-Dawley rats. Animals were given cyclosporine and subjected to renal ischemia by temporarily occluding both the renal artery and vein. Our data demonstrate no significant difference in serum creatinine among rats subjected to renal ischemia, cyclosporine, or cyclosporine-vehicle cremophor EL administration, or the control group. On the other hand, renal ischemia in combination with cyclosporine resulted in rapid and marked deterioration in renal function with serum creatinine peaking on Day 2. The most significant rise was in rats that received cyclosporine 4 hr prior to induction of renal ischemia (4.7 +/- 0.5 mg/dl), followed by those that received cyclosporine 4 and 24 hr postischemia (2.8 +/- 0.5 and 3.2 +/- 0.7 mg/dl, respectively). Cyclosporine administration 24 hr prior to renal ischemia resulted in the least elevation of the serum creatinine (2.1 +/- 0.5 mg/dl) and the earliest return to the baseline value. Our data suggest that the timing of cyclosporine administration in rats subjected to renal ischemia influences the extent of renal injury and the subsequent recovery of renal function.

Renal allograft outcome in the cyclosporine era: comparison between intermediate-term failure and long-term survival

A single center experience of 160 cyclosporine-treated renal allografts that survived longer than 1 year was reviewed in an attempt to analyze the contribution of selected parameters to long-term survival. Sixty-one grafts were lost between 1 and 5 years, with the remaining functioning for longer than 5 years. Parameters with a significant influence on long-term survival included both quality of early graft function, with 13% of long-term survivors having delayed function, compared to 52% among the short-term survival group, and the incidence of acute rejection in the first year posttransplant (31% in long-term survivors compared to 63% in the short-term survival group). A marker for long-term survival (greater than 5 years) was a lower serum creatinine at 1 year (1.9 +/- 0.1 mg/dl, compared with 2.6 +/- 0.2 mg/dl in the short-term survival group). Recipient race, original renal disease, number of transplants and/or transfusions, panel reactive antibodies, and human leukocyte antigens matching did not appear to influence long-term outcome.

Retrospective analysis of posttransplantation diabetes mellitus in black renal allograft recipients

OBJECTIVE

To study the incidence, outcome, and possible etiopathogenic factors involved in posttransplantation diabetes mellitus in cyclosporine-treated black renal allograft recipients.

RESEARCH DESIGN AND METHODS

One hundred thirty-eight nondiabetic black renal transplant recipients whose grafts survived greater than 1 yr were studied retrospectively.

RESULTS

Twenty-eight (20.3%) patients developed posttransplantation diabetes mellitus, 46 and 75% were diagnosed by 6- and 12-mo posttransplantation, respectively, and 46% were insulin dependent. Diabetes was more frequently encountered in older recipients and recipients of cadaveric kidneys but was independent of sex, number of transplants, incidence of acute rejection, percentage of body weight gain, steroid or cyclosporine dose, and use of beta-blockers and/or diuretics. Renal function was similar in the diabetic group compared with the control group. Actuarial 5-yr graft survival was 82% in the diabetic cohort compared with 78% in the control group, with chronic rejection accounting for all graft losses within the diabetic group.

CONCLUSIONS

Twenty percent of black cyclosporine-treated renal allograft recipients developed diabetes mellitus in the posttransplantation period. However, its presence did not appear to influence intermediate-term graft or patient survival.

Racial differences in renal transplant outcome of insulin-dependent diabetic recipients in the cyclosporine era

In an attempt to analyze the influence of race on renal allograft outcome among insulin-dependent diabetic uremics, all 109 cyclosporine treated transplants were studied. Black recipients were noted to have inferior 1 year survival for both living related and cadaver donor grafts when compared with both whites and Hispanics (67% and 43% vs. 92% and 84%, 100% and 80%, respectively, p less than 0.01). Nonimmunologic causes accounted for 69% of graft losses among blacks, compared with 39% and 33% in whites and Hispanics, respectively. Among long-term survivors, however, renal function remained relatively stable among all racial groups. This differing trend among black diabetic recipients suggests the need for aggressive cardiac workups before transplantation, and judicious immunosuppression in the posttransplant period.

Photorefractive time-integrating correlator

We propose and demonstrate a new configuration of a photorefractive time-integrating correlator system using acousto-optic devices to process rf signals. In our system, two rf signals are transferred onto two laser beams by two acousto-optic devices, and the beams interact inside a photorefractive crystal to form a grating for time integration and correlation. The novelty of our scheme is that the direction of the rf signal in the beams is orthogonal to the resulting grating wave vector inside the crystal. This new geometry eliminates any resolution-limiting cross talk that arises from undesirable beam interactions. It also permits a longer crystal interaction length, which reduces constraints on the photorefractive material.

Diffraction efficiency of volume holograms written by coupled beams

We describe volume holograms written in photorefractive crystals in which the writing beams experience two-beam coupling. We obtain analytic expressions for the diffraction efficiency of a weak reading beam that has a different polarization from the writing beams. Good agreement is obtained between experimental and theoretical results.

Human placental protein methylase--I. Purification and characterization

1. Protein methylase I (S-adenosylmethionine[:]protein-arginine N-methyltransferase; EC 2.1.1.23) which methylates protein-bound arginine residues has been purified from human term placenta 400-fold with an approximate yield of 6%. 2. When histone was used as in vitro substrate, the methylation products were found to be NG-mono-, NG, NG-di- and NG, N'G-dimethylarginine. The enzyme was found to be sensitive toward Cu2+ with Ki value of 8 x 10(-5) M. The Km value for S-adenosyl-L-methionine was 5 x 10(-6) M. 3. When this partially purified protein methylase I was incubated with isolated human placental nuclei and S-adenosyl-L-[methyl-3H]methionine, the major endogenous [methyl-3H]-labeled proteins were protein species of 23, 38, 45 and 68 kDa, the 23 kDa species being the most predominant. 4. The endogenous enzyme activity during the pregnancy increased significantly, reaching more than 4 times the initial activity at the end of term.

The impact of ciclosporin in patients with adult polycystic kidney disease following transplantation

In order to evaluate the impact of ciclosporin in patients with adult onset polycystic kidney disease (ADPKD) following renal transplantation, we performed a single-center study of all (n = 65) patients with this disorder since 1978, 43 of whom received CSA (PC-CSA) with the remaining 22 treated with azathioprine (PC-AZA). An additional group of 45 age- and time-matched group of non-polycystic CSA-treated patients (nonPC-CSA) were used as a separate control group. Patient and graft survivals at 1 and 5 years were similar in PC-CSA when compared to nonPC-CSA. The commonest causes of death in both groups were cardiovascular related. The incidence of posttransplant hypertension and acute rejection were also similar. Urinary tract infections (UTIs) were, however, more frequent among PC-CSA (11 and 33% pre- and posttransplant respectively) when compared to the nonPC-CSA (2 and 17% pre- and posttransplant respectively). The PC-CSA cohort showed improved 1-year patient and graft survivals when compared to PC-AZA (94 and 70% vs. 72 and 34%) with less rejection episodes (42 vs. 88%) during the first year posttransplant but a higher mean serum creatinine at the end of the first year (2.0 vs. 1.6 mg/dl, 176.6 vs. 141.3 mumol/l). Posttransplant hypertension (67 vs. 70%) and UTIs (33 vs. 33%) were, however, similar in both groups. In summary, renal transplantation in ADPKD in the CSA era is associated with equal patient and graft survivals when compared with nonpolycystic patients of comparable age, but superior results when compared with the earlier azathioprine era.

Prolonged simple cryothermic immersion storage of rat heart isografts: a preliminary study

In order to extend preservation time for heart transplant, cryothermic immersion storage was studied in a rat heart isograft model. Rat hearts preserved at -2 to 0 degrees C for up to 96 h were successfully transplanted with no deleterious effects noted on defrosting and reperfusion with long-term survival beyond 60 days of transplant.

Prognostic factors of nasopharyngeal carcinoma: a multivariate analysis

Between 1979 and 1985, 561 patients with nasopharyngeal carcinoma were reviewed to determine prognostic factors that may influence survival. Sex (p = 0.294) and histopathology (p = 0.677) had no correlation to the actuarial survival, whereas the site of cervical metastasis (p = 0.001) and the radiation doses to the nasopharynx and regional lymph nodes (p = 0.03) were both significant when one used univariate analyses. Cox's multivariate regression model revealed that the presence rather than the site of distant metastases was the single most important independent factor influencing the treatment outcome (p less than 0.0001). The addition of chemotherapy, on the other hand, did not show a survival benefit even when one took available confounding factors into account. There are, however, survival advantages associated with: (a) young age (less than or equal to 40 years), (b) asymptomatic status, (c) Stage I or II lesions, and (d) biopsy via nasopharynx instead of neck nodes. These favorable prognostic factors may be used for therapeutic guidance and end-result reporting.

The pattern of organ donation in a large urban center

Despite increasing referrals for organ donation in metropolitan New York, procurement has remained essentially unchanged from 1983 through 1988 at 9 to 13 per million population, falling far short of increasing demand. This is not due to delay in the diagnosis of brain death, higher discard rates, or increased medical unsuitability, although exclusion because of human immunodeficiency virus (HIV) disease, or risk thereof, has increased and now accounts for 38% of exclusions. Consent for organ donation remains consistently low among blacks (24%), has increased among Hispanics from 17% in 1984 to 47% in 1988, and remains the highest, but without improvement, among whites. Causes for the observed stagnation and potential corrective factors include poorly focused educational efforts, lack of sensitivity to the grieving family by hospital personnel, physician frustration at the increasingly prominent role of government and its regulations in the practice of medicine, and eradication of competition between local organ procurement agencies.

Optical pattern classifier with Perceptron learning

An optical realization of a single layer pattern classifier is described in which Perceptron learning is implemented to train the system weights. Novel use of the Stokes's principle of reversability for light is made to realize both additive and subtractive weight modifications necessary for true Perceptron learning. This is achieved by using a double Mach-Zehnder interferometer in conjunction with photorefractive hologram recording. Experimental results are given which show the high quality subtractive changes that can be made.

Image amplification by two-wave mixing in photorefractive crystals

Coherent amplification of images by two-wave mixing in photorefractive crystals is examined with attention given to processing in the Fourier domain. It is shown that the gain that is experienced as the probe image traverses the crystal is approximately uniform across the image. The gain can be expressed as a function of the average probe to pump intensity ratio. Experimental verification is given to support the theory.

Spatial amplification: an image-processing technique using the selective amplification of spatial frequencies

A novel technique of processing optical images that we call spatial amplification is proposed and demonstrated. The basic idea is to amplify coherently a set of selected spatial frequency components of an image. Unlike in the usual spatial filtering techniques, in which the components are selectively blocked out at the Fourier plane of a coherent processor, spatial amplification does not discard any of the incident image information. The advantages of the proposed technique over spatial filtering include high energy efficiency and the possibility for cascading several stages. In the demonstrated experiments, the required amplification is provided by two-beam energy coupling in a photorefractive BaTiO(3) crystal with a nonuniform pump beam.

[Effect of eye shielding block position on dose to lens during radiation therapy]

The lens of the eye is very sensitive to radiation and a low dose of radiation may induce cataracts a few years after radiation therapy. In treatment of head and neck tumors, such as cancer of the ethmoid or maxillary sinus, an adequate eye shielding block is mandatory for reducing the lens dose in order to prevent cataract formation. Experiments were designed to simulate the setup of the lens during radiation therapy and it was observed that the dose to the lens was correlated with the distance between the eye shielding block and the eye surface for Co-60, 10MV and 6MV X-rays. With properly fabricated divergent blocks, the optimal shielding points were found to be 6 cm, 0.9 cm and 1.4 cm above the eye surface for Co-60, 10MV and 6MV X-rays, respectively. In a 10 x 10 cm2 field, by moving the eye shielding block on the blocking tray to the optimal shielding point near the surface, the dose to the lens can be reduced from 14% to 8% for Co-60 beams and from 17% to 7% for 10MV and 6MV X-rays. This effect is more evident in larger field sizes. We recommend that the eye shielding block be placed at the optimal shielding point to minimize the dose to the lens. If the eye shielding block cannot be placed at the optimal shielding point, a simple coin placed on the eye lid surface will also reduce the lens dose substantially when a regular eye shielding block is placed on the blocking tray (Lin's coin effect).

Reduced DNA topoisomerase II in VP-16 resistant mouse breast cancer cell line

VP-16 resistant cells, FvprB350 (50B-3), were isolated from mouse breast cancer cell line FM3A. 50B-3 cells showed 84-fold higher resistance than their parent cells. Reduced drug uptake was not found in resistant cells. Quantitative analysis of drug-stimulated DNA cleavage activity using 3'32P end-labeled pBR322 restriction fragments showed that VP-16 stimulated DNA-topoisomerase II cleavable complex forming activity in crude nuclear extract from 50B-3 cells was approximately one-fifth as compared with that of FM3A wild-type cells. Dot-blot analysis of RNA extracted from the two cell lines showed that mRNA levels of topoisomerase II in 50B-3 cells drastically decreased and catalytic activity was also 1/2-1/3 as compared with that of parent cells. 50B-3 cells showed cross resistance to VM-26, m-AMSA, adriamycin. These findings suggest that reduced topoisomerase II activity (cellular levels) and cleavable complex forming activity may be significant factors in the marked drug resistance.

Isolation and characterization of VP-16 resistant human leukemia cell line

VP-16 resistant cells, designated VP-16K6-1 (K6-1) were isolated from human acute lymphoblastic leukemia cell line RPMI 8402. IC50 value against VP-16 were 11-fold higher than their sensitive parental cell line. The membrane permeability of the drug was not responsible for resistance in K6-1 cells. K6-1 cells showed resistance in drug-induced DNA strand breaks (single strand breaks) determined by the alkaline sucrose gradient sedimentation method. Dot-blot analysis of RNA extracted from 2 cell lines showed that the mRNA levels of DNA topoisomerase II in K6-1 cells decreased slightly compared with that of parent cells. However, Topo II activities were similar in wild-type and K6-1 cells. In addition, K6-1 cells exhibited cross-resistance only to VM-26. These data suggest that a reduced intracellular Topo II level may contribute to drug resistance as an important factor in K6-1 cells.