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.

DNA topoisomerase: the mechanism of resistance to DNA topoisomerase II inhibitor VP-16

K6-1 and 50B-3 cell lines, resistant to VP-16, a DNA topoisomerase II inhibitor, were established from two different types of cells respectively: human T-cell derived acute lymphoblastic leukemia cell line RPMI8402 and mouse mammary tumor cell line FM3A. IC50 values of K6-1 and 50B-3 cells to VP-16, evaluated by the colony forming ability on methyl cellulose medium, were 11- and 84-fold higher than their sensitive parental cell lines, respectively. Membrane permeability of the drug was not responsible for the resistance in K6-1 and 50B-3 cells. Quantitative analysis of drug-induced DNA cleavage (so called cleavable complex formation) was performed using 32P end-labeled pBR322 restriction fragments. The formation of the topoisomerase II-DNA cleavable complex stimulated by VP-16 in 50B-3 cells was approximately 1/5 compared with that of FM3A wild-type cells. Dot blot analysis of RNA extracted from these cell lines showed that the levels of mRNA for DNA topoisomerase II in 50B-3 cells were markedly decreased and that catalytic activity was reduced to 1/2-1/3 compared with that of parent cells. There was a slight reduction of DNA topoisomerase II mRNA in K6-1 cells. However, DNA topoisomerase II activities were similar in wild-type and K6-1 cells. In addition, 50B-3 cells showed cross resistance to VM-26, m-AMSA and adriamycin, whereas K6-1 cells exhibited increased resistance only to VM-26. These resistant cell lines did not show collateral sensitivity to CPT-11, a DNA topoisomerase I inhibitor. Southern blot analysis of genomic DNA did not show any change in the restriction pattern of the DNA topoisomerase II gene between the parental and their resistant lines. These findings suggest that the reduced levels in DNA topoisomerase II contribute to the drug resistance of 50B-3 cells.