Expansion of the Mexican Rice Borer (Lepidoptera: Crambidae) into Rice and Sugarcane in Louisiana

The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an invasive pest of sugarcane, Saccharum spp., rice, Oryza sativa L., and other graminaceous crops in the Gulf Coast region of the United States. Traps baited with E. loftini female sex pheromones were used to document establishment and distribution of E. loftini near sugarcane, rice, and noncrop hosts in seven southwest Louisiana parishes from 2009 to 2013. Additional field surveys documented larval infestations in commercial sugarcane and rice. After its initial detection in 2008, no E. loftini were detected in Louisiana in 2009 and only two adults were captured in 2010. Trapping documented range expansion into Cameron, Beauregard, and Jefferson Davis parishes in 2011 and Allen, Acadia, and Vermilion parishes in 2013. During the course of this study, E. loftini expanded its range eastward into Louisiana 120 km from the Texas border (≈22 km/yr). Surveys of larval infestations provided the first record of E. loftini attacking rice and sugarcane in Louisiana. Infestations of E. loftini in rice planted without insecticidal seed treatments in Calcasieu Parish reached damaging levels.

Glass-like phonon scattering from a spontaneous nanostructure in AgSbTe2

Materials with very low thermal conductivity are of great interest for both thermoelectric and optical phase-change applications. Synthetic nanostructuring is most promising for suppressing thermal conductivity through phonon scattering, but challenges remain in producing bulk samples. In crystalline AgSbTe2 we show that a spontaneously forming nanostructure leads to a suppression of thermal conductivity to a glass-like level. Our mapping of the phonon mean free paths provides a novel bottom-up microscopic account of thermal conductivity and also reveals intrinsic anisotropies associated with the nanostructure. Ground-state degeneracy in AgSbTe2 leads to the natural formation of nanoscale domains with different orderings on the cation sublattice, and correlated atomic displacements, which efficiently scatter phonons. This mechanism is general and suggests a new avenue for the nanoscale engineering of materials to achieve low thermal conductivities for efficient thermoelectric converters and phase-change memory devices.

Movement of Mexican rice borer (Lepidoptera: Crambidae) through the Texas rice belt

Pheromone-baited traps were used to monitor the movement of the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), through the Texas rice belt from 2000 to 2005. Based on location of discovery in each county and year, the average rate of spread from 1980 to 2005 was 23 km/yr. From 2000 to 2005, the leading edge of the infestation has moved 16.5 km/yr toward Louisiana. The 1.8-fold increase (99% confidence interval) of the area occupied from 2000 to 2005 in the Texas rice belt indicates an expansion of the distribution of E. loftini. If movement continues to occur at similar rates, E. loftini will reach Louisiana by 2008.

Insect succession and decomposition of wildlife carcasses during fall and winter in Louisiana

Fourteen fresh animal carcasses were monitored throughout decomposition in a mixed flatwood forest in East Baton Rouge Parish, LA, from 5 October to 7 December 1999 (fall) and from 18 January to 30 March 2000 (winter). Species composition and residency patterns of necrophilous insects were documented for four animal species per seasonal experiment: one Louisiana black bear (threatened species), two white-tailed deer, two alligators, and two swine (experimental reference). Results suggested variation in species composition associated with temperature (fall versus winter conditions) and carcass type. In total, 89 species from 39 families and three classes were manually collected from the seven fall carcasses. Ninety-five species from 38 families and three classes were collected at the seven winter carcasses. Overall arthropod diversity was greatest for fall deer and winter swine carrion. Fall alligator carcasses were associated with fewer taxa than the three mammal species during both seasons. The hairy maggot blow fly, Chrysomya rufifacies (Macquart), was the dominant species of the fall study, impacting developmental rates and overall carrion community structure. The winter study was characterized by prolonged carcass decomposition and reduced insect activity due to fluctuating ambient temperatures.

Spring succession of necrophilous insects on wildlife carcasses in Louisiana

Seven fresh animal carcasses were monitored throughout decomposition in a mixed flatwood forest in East Baton Rouge Parish, LA from 1 April to 1 July 1999. Succession patterns of necrophilous insects were documented for the following: one Louisiana black bear (threatened species), two white-tailed deer, two alligators, and two swine as the experimental reference. Our results suggest variation in the species composition of necrophilous insects among animal carcass types. A total of 93 arthropod species, from 46 families and three classes, were manually collected from the seven carcasses. Only 19 insect species were collected on all four animal types and were represented by eight families: Coleoptera: Histeridae, Nitidulidae, Silphidae, Staphylinidae; Diptera: Calliphoridae, Muscidae, Piophilidae, Sepsidae. Eleven of the 46 families were not collected at either alligator site but were observed at bear, deer, and swine carrion: Coleoptera: Cleridae, Dermestidae, Geotrupidae, Scarabaeidae; Diptera: Micropezidae, Sarcophagidae, Syrphidae; Hymenoptera: Apidae; Lepidoptera: Nymphalidae; and Odonata: Libellulidae. Residency and succession patterns of necrophilous insects are presented for each animal type with particular emphasis on selected fly (Calliphoridae, Muscidae, Piophilidae, Stratiomyidae) and beetle species (Cleridae, Dermestidae, Histeridae, Nitidulidae, Silphidae, Staphylinidae).

The Baylor College of Medicine experience with gold seed implantation

Advances in imaging technology and implant technique have led to the resurgent interest and practice of brachytherapy for the treatment of prostate cancer. Brachytherapy is a form of radiation treatment in which radioactive sources are placed directly into the tumor; it offers the advantage of maximizing the radiation dose delivered to the tumor while sparing the adjacent normal tissue. Permanent implants have become an important component of radiation delivery. Interstitial gold radioisotope (Au-198) implants for prostate cancer were introduced at Baylor College of Medicine in 1965. The rationale for using Au-198, instead of the two most commonly used radioisotopes, Palladium-103 (Pd-103) and Iodine-125 (I-125), is discussed, and the Baylor implant technique is compared to that used in other centers. Retrospective review divides the patient population into pre-ultrasound versus post-ultrasound eras. Dosimetric calculation and disease control with the Au-198 seed implant for prostatic cancer are reviewed for the two different eras; toxicity is evaluated in the post-ultrasound era only. In the pre-ultrasound era, 510 patients were treated with pelvic lymph node sampling and gold seed insertion of the prostate followed by external beam radiation. In the post-ultrasound era, 54 patients were treated definitively with ultrasound-guided transperineal Au-198 implant followed by external beam irradiation. A small group of 30 patients in the post-ultrasound era were evaluated for the efficacy of Au-198 re-implantation for locally recurrent disease.

Fifteen-year survival and recurrence rates after radiotherapy for localized prostate cancer

PURPOSE

To determine 15-year survival and recurrence rates after radiotherapy for localized prostate cancer.

METHODS

One hundred thirty-six patients with clinically localized prostate cancer treated from 1966 to 1974 with interstitial gold seed and external-beam irradiation were evaluated to determine the probability of recurrence and survival > or = 15 years after therapy. All patients were surgically staged with pelvic lymphadenectomy and none received hormonal therapy before relapse.

RESULTS

Overall, 60 patients (44%) have never recurred, although 57% (34 of 60) of these same patients have died of causes other than prostate cancer. Local progression developed in 39% of patients and distant metastases in 42%. At 15 years, the probability of dying of prostate cancer was 33%+/-8% (% +/- 2SE) and of all causes was 72%+/-8%. In clinical stage A2 and B, 29%+/-9% of patients died of their cancer within 15 years, compared with 57%+/-21% in stage C1, while only 18%+/-8% with clinical stage A2 and B and negative lymph nodes died of cancer within this period. In contrast, the prostate cancer mortality rate at 15 years was high for patients with positive nodes regardless of the stage of the primary tumor (73% for A2 and B; 71% for C1). Patients with nodal metastases, poorly differentiated tumors, and advanced local disease all had a significantly (P < .0001) increased risk of cancer death.

CONCLUSION

The cancer-specific mortality rate for patients with stage A2 and B tumors and negative nodes compares favorably with other series of patients treated with radiation therapy and > or = 15 years' follow-up evaluation. While local progression rates are high and associated with a substantial risk of prostate cancer death, many patients live with the disease and ultimately die of causes other than prostate cancer.

World Health Organization Consensus Committee recommendations concerning the diagnosis of BPH

The expert committees, which met in Paris in June 1991 under the patronage of WHO to establish a consensus concerning BPH, adopted the recommendations summarised in this report. Despite certain criticisms which can be made, these recommendations offer the advantage of simplicity and uniformity, thereby constituting a "universal language". This will facilitate comparison of patients and therapeutic results, both in everyday practice and in the course of clinical trials. These recommendations will be periodically re-evaluated in the light of clinical experience and technological progress.

The frequency and morbidity of local tumor recurrence after definitive radiotherapy for stage C prostate cancer

Radiotherapy is reported to provide good control of locally advanced prostate cancer. However, few long-term studies have assessed the morbidity related to local tumor recurrence in patients treated with radiotherapy alone (without hormonal manipulation). To determine the frequency and severity of morbidity related to local recurrence we reviewed the course of all patients with clinical stage C prostate cancer treated at our institution between 1966 and 1979 with bilateral pelvic lymph node dissection, radioactive gold seed implantation and external beam irradiation therapy to the prostate. Of the 121 patients 60% died and the 40% still alive at the time of review were followed for a mean of 8.1 years (range 3.3 to 14.8 years). Over-all, 64 patients (53%) had local recurrence, which was defined as a clinical event causing signs or symptoms and was proved by biopsy. On an actuarial basis the risk of local recurrence was 43 +/- 10% (mean +/- 2 standard errors) at 5 years and 74 +/- 11% at 10 years. Any symptomatic episode requiring active intervention or causing morbidity was denoted an adverse event. There were 162 adverse events among the 73 patients (2.2 adverse events per patient): 69% of these were severe (requiring surgical intervention) and 55% were chronic (more than 3 months in duration). The most common cause of an adverse event was bladder outlet obstruction requiring transurethral resection of the prostate (44 patients); 16 patients (13%) became incontinent. Hydronephrosis developed in 24 patients (20%). Local recurrence after definitive radiotherapy for our patients with stage C prostate cancer was common and was associated with serious morbidity, frequently requiring surgical intervention. Radiotherapy alone may not be sufficient to provide long-term local control of stage C prostate cancer.

The risk of dying of prostate cancer in patients with clinically localized disease

From 1966 to 1979, 360 patients with clinical stages A2, B and C1 prostate cancer underwent staging pelvic lymphadenectomy, and completed a course of combined interstitial radioactive gold seeds and external beam radiotherapy. All patients had a normal serum prostatic acid phosphatase level and a bone scan negative for metastases. All patients were followed until death or for a mean of 7.3 years (range 1.2 to 18.25 years) for those alive at analysis. To determine the risk of dying of prostate cancer we reviewed the records of the 142 patients (39%) who died. At analysis 21% of the patients had died of prostate cancer and 17% of other known causes. The cause of death could not be determined in 4 patients (1%). Cardiovascular disease accounted for a fifth of all deaths. The actuarial risk of death of prostate cancer for all patients was 8 +/- 3% (+/- 2 standard errors) at 5 years and 30 +/- 7% at 10 years. The risk of death of all causes was 16 +/- 4% at 5 years and 46 +/- 7% at 10 years. An increased risk of cancer death was associated with established risk factors, including advanced local disease, poorly differentiated histology, pelvic nodal metastases and distant recurrence. We also noted a substantial risk of cancer death in patients who had local tumor recurrence. While previous studies have reported a relatively low incidence of cancer deaths (4 to 17%) in patients initially diagnosed with localized disease, our data suggest that prostate cancer is the major cause of mortality in such patients. Aggressive curative therapy, regardless of treatment modality, should be considered for localized prostate cancer in men with a life expectancy of 10 or more years.

Controlled inversion therapy: an adjunct to the elimination of gravity-dependent fragments following extracorporeal shock wave lithotripsy

The retention of passable stone debris is the primary shortcoming of extracorporeal shock wave lithotripsy. Residual stone debris is located almost universally in gravity-dependent caudal calices. Our findings suggest that multiple sessions of controlled inversion therapy could have a beneficial role in the postoperative management of this select group of patients.

Prognostic significance of lymph nodal metastases in prostate cancer

Pelvic lymph node metastases indicate a poor prognosis for patients with clinically localized prostate cancer but the significance of minimal nodal metastases still is debated. We determined the progression and cancer specific survival rates based on the extent of nodal metastases in 511 patients followed for a mean of 8.6 years (range 2.5 to 17.5 years) after bilateral pelvic lymph node dissection and irradiation therapy. The patients were divided into 4 groups based on the extent of nodal metastases: NO--negative nodes (359 patients), N1--a single microscopic positive node (37), N2--multiple microscopic positive nodes (86) and N3--grossly positive or juxtaregional nodes (29). The risks of distant metastases and of dying of prostate cancer were much greater in the 152 patients with positive nodes (N+) than in those with negative nodes (p less than 0.00005). The risk of metastatic disease at 10 years was only 31 +/- 7 per cent for the NO patients compared to 83 +/- 7 per cent for the N+ patients, and the risk of dying of prostate cancer was only 17 +/- 6 per cent at 10 years for the NO group and 57 +/- 11 per cent for the N+ patients. Patients with a single microscopic node (N1) had a pattern of progression and cancer specific mortality rate similar to patients with more extensive nodal metastases and markedly worse than patients with negative nodes. The risk of distant metastases was 80 +/- 15 per cent at 10 years for the N1 group, 84 +/- 11 per cent for the N2 group and 88 +/- 13 per cent for the N3 group, while the risk of dying of prostate cancer at 10 years was 40 +/- 19, 66 +/- 15 and 58 +/- 24 per cent, respectively. The finding of a single pelvic lymph node containing microscopic metastatic disease markedly worsened the prognosis of our patients with prostate cancer. Once prostate cancer is found within the pelvic lymph nodes the patient has systemic disease unlikely to be controlled by pelvic lymph node dissection and radiotherapy.

The risk of distant metastases after transurethral resection of the prostate versus needle biopsy in patients with localized prostate cancer

Although transurethral resection of the prostate provides an effective treatment for obstructive voiding symptoms associated with prostate cancer, there is growing concern about the possible role of transurethral resection in the dissemination of this malignancy. To determine the effect of transurethral resection on the rate of development of distant metastasis, we analyzed a large series of patients (379) treated at our institution with definitive radiotherapy for localized prostate cancer that was diagnosed by either needle biopsy or transurethral prostatic resection. In our series the presence of lymph node metastasis was documented by pelvic lymph node dissection in all patients. An initial univariate analysis suggested that patients diagnosed by transurethral resection had distant metastases significantly more rapidly than patients diagnosed by needle biopsy. However, transurethral resection usually was performed because of the presence of obstructive voiding symptoms and such patients were much more likely to have positive lymph node dissections than patients without obstructive voiding symptoms. A proportional hazards regression analysis showed that nodal status and the degree of obstructive voiding symptoms at diagnosis were independent and powerful predictors of the interval to distant metastases, along with stage and grade. The type of initial biopsy (transurethral prostatic resection versus needle biopsy) had no independent prognostic significance in this analysis. Among patients who had substantial obstructive voiding symptoms there was no significant difference in interval to distant metastases between the transurethral prostatic resection and needle biopsy groups. We conclude that the apparent adverse effect of transurethral prostatic resection results from the poor prognosis of tumors causing obstructive voiding symptoms rather than as a direct result of the resection itself.

Development of fibrotic penile lesions secondary to the intracorporeal injection of vasoactive agents

Fibrotic penile lesions developed in 4 patients who had undergone intracorporeal injection of vasoactive agents. These lesions persisted for at least 3 months, and in some instances they caused pain and curvature of the penis during erection.

The prognostic significance of post-irradiation biopsy results in patients with prostatic cancer

To evaluate the prognostic significance of post-irradiation biopsy results in patients with prostatic cancer, we reviewed the records of 803 patients who had been treated with pelvic lymph node dissection, radioactive gold seed implantation and external beam irradiation. Of the patients 124 had 1 or more biopsies within 6 to 36 months after completion of radiotherapy when there was no evidence of local or distant recurrence of tumor. Patients were followed for a mean of 64 months (range 14 to 175 months) and received no other therapy before relapse. Over-all, 43 of these patients (35 per cent) had a positive biopsy result. The incidence of positive biopsy results correlated directly with the initial stage of the tumor, ranging from 22 per cent of stage B1N to 50 per cent of stage C1 lesions. However, biopsy results did not correlate with the grade of the tumor. Local recurrence and distant metastases were much more common among patients with a positive biopsy result (p equals 0.0006). Local recurrence developed in 58 per cent of the patients with a positive biopsy by 5 years and in 82 per cent by 10 years. Of those in whom all biopsies were negative only 18 per cent had local recurrence by 5 years and 32 per cent by 10 years. Biopsy results retained their prognostic significance even among the more favorable subset of patients whose pelvic lymph nodes were negative initially and those with a normal prostatic examination at biopsy. These results indicate that a post-irradiation prostate biopsy 6 to 36 months after completion of treatment can be used to determine the efficacy of a particular radiotherapeutic regimen as well as the success or failure of radiotherapy in an individual patient.

Incidental carcinoma of the prostate at the time of transurethral resection: importance of evaluating every chip

Incidental adenocarcinoma of the prostate has been divided into stage A1--less than 3 foci of well differentiated adenocarcinoma present and stage A2--3 or more foci of poorly differentiated tumor present. The clinical significance of these 2 stages has been well documented, with stage A1 lesions causing no increased mortality, while up to 30 per cent of patients with clinical stage A2 disease will have positive pelvic lymph nodes at exploration and, thus, will have surgical stage D1 tumor. Most pathology laboratories submit only a fraction of the transurethral resection chips for permanent blocks. In an effort to evaluate the over-all incidence and distribution of stages A1 and A2 lesions were began a prospective study in 1978 whereby all prostatic chips were submitted for permanent sections. A review of 500 consecutive cases of transurethral resection for clinically benign prostates before 1978 revealed 43 cases of adenocarcinoma: 10 (23 per cent) stage A1 and 33 (77 per cent) stage A2. A review of a similar series of 500 consecutive patients since 1978 revealed 71 cases of adenocarcinoma: 17 (24 per cent) clinical stage A1 and 54 (76 per cent) clinical stage A2. Thus, we found that since 178 incidental adenocarcinoma of the prostate has increased by 65 per cent and the distribution of stages A1 and A2 lesions has remained unchanged, 76 per cent of these lesions being clinical stage A2 with its much greater clinical significance. Evaluation of every chip does make a clinically significant difference in the subsequent management of patients with incidental adenocarcinoma of the prostate.

Renal vein thrombosis in renal cell carcinoma. Proteinuria as diagnostic sign

In 4 patients with hypernephroma and extension of the tumor thrombus into the renal vein, there has been a significant degree of proteinuria. We believe that the proteinuria in association with a renal mass suggests a tumor thrombus in the renal vein and warrants the preoperative inferior venacavogram. After a larger number of patients have been studied, it may become clear that patients who do not have proteinuria do not have renal vein or vena caval involvement. If this proves to be the case, these patients may be selectively spared inferior venacavography. For the present time in patients with hypernephroma, we can only recommend that the index of suspicion for renal vein involvement with tumor thrombus should remain high if the patient has significant proteinuria.

Inverted papilloma of ureter

Two cases of inverted papilloma of the ureter are reported. The possible etiology and clinical significance of this previously unreported lesion are discussed.

Cell surface A, B, or O(H) blood group antigens as an indicator of malignant potential in stage A bladder carcinoma

The major blood group antigens A, B or O(H) are present on normal bladder epithelium. The presence or absence of these antigens on the cell surface of bladder tumors has been determined in a retrospective longitudinal study using biopsy material from 322 patients who fit the following criteria: 1) the patient presented initially with a superficial bladder tumor, 2) the patient had followup examination for at least 5 years or until evidence of tumor invasion of bladder muscle and 3) the paraffin-embedded tumor specimens were still available. Of 80 patients with stage A tumors that subsequently became invasive 71 (88 per cent) showed deletion of A, B or H antigens from the original superficial tumor. On the other hand, of 146 patients who had no recurrence of superficial tumor for at least 5 years 127 (87 per cent) retained A, B or H antigens. Of 96 patients who had 1 or more superficial recurrences 87 (90 per cent) retained antigens on the initial and subsequent tumors. Analysis of transitional cell surface antigens should help in the identification of those patients with superficial disease who are at greatest risk for invasive bladder cancer.

Adjunctive chemotherapy of infection-induced staghorn calculi

Bacteria induce urinary crystallization of struvite and carbonate-apatite as a by-product of ureolysis by urease. Eradication of infection and/or inhibition of urease with acetohydroxamic acid for 5 to 30 months retarded stone growth and brought about partial or comple dissolution of stones in 9 patients. Long-term chemotherapy with antimicrobial agents that achieve steril urine or acetohydroxamic acid in those patients with recalcitrant infection lessens the risk of recurrent calculogenesis.

Iatrogenic renal vascular injury

Bilateral arteriovenous fistulas secondary to percutaneous needle biopsy of each kidney developed in a patient with malignant hypertension and chronic failure. The fistulas with aneurysmal formation and hematuria were of such magnitude that bilateral nephrectomy was required for control. The patient is now normotensive and is maintained on hemodialysis. The advisability of renal needle biopsy in uncontrolled hypertension is questioned. Cases of intrarenal arteriovenous fistulas resulting from percutaneous needle biopsy of the kidney are being reported with increasing frequency. The exact incidence of fistula formation after kidney biopsy is unknown, but several series based on arteriographic studies show an incidence as high as 18 per cent. Although many of these fistulas disappear spontaneously, approximately 4 per cent persist. A review of the literature failed to reveal the incidence of aneurysmal formation. Our case was complicated by formation of bilateral renal arteriovenous fistulas secondary to repeat bilateral percutaneous needle biopsy and right open renal biopsy. Subsequent gross hematuria from the right ureteral orifice also resulted which was proved by cystoscopy and required replacement with several units of blood. The likelihood of rupture led to bilateral nephrectomy.

Immunoglobulin A in split ejaculates of patients with prostatitis

7S and 11S IgA (immunoglobulin A) levels in split ejaculates of 17 patients with chronic prostatis and 16 normal subjects were studied by the Hanson radial immunogel filtration method. The results suggest at least in certain cases of prostatitis increase of IgA level involves elevation of both types of IgA, and they are mainly of prostatic origin.

Clinical use of immunoelectrophoresis of split ejaculates. I. Variation of patterns due to antisera

As a preliminary investigation for the clinical application of immunoelectrophoresis of ejaculate in the diagnosis of male reproductive organ diseases, variations of immunoelectrophoretic patterns in normal subjects due to the difference of antigenicity between split ejaculates were demonstrated with rabbit antisera. Fresh samples and antisera against them gave larger numbers of and more intense precipitin lines than in stored samples. The precipitin lines developed by acid phosphatase were most remarkable between first portion of ejaculate (F1) and anti-F1, whereas the line caused by protein from the seminal vesicle was most prominent between the remainder of the ejaculate following F1 (F2) and anti-F2.

Renal complications of drug addiction

The kidney is one of the target organs involved as a consequence of the systemic complications seen in drug abusers. This may manifest itself in one of the following forms: acute hepatitis with modest proteinuria (less than 2 Gm. per day); bacterial endocarditis with hematuria, azotemia, and a focal or diffuse glomerulonephritis; the nephrotic syndrome with focal mesangial sclerosis and diffuse interstitial nephritis often pursuing a fulminant course terminating in uremia; acute renal failure secondary to rhabdomyolysis and myoglobinuria; polyarteritis nodosa with renal involvement; and obstructive uropathy secondary to fungus ball in the urinary tract.

Radiotherapy in the management of stage C carcinoma of the prostate

A small number of patients with limited stage C carcinoma of the prostate have been treated with combined interstitial and external beam radiotherapy with gratifying results. Whereas more patients will have to be followed for at least 10 to 15 years to completely evaluate this modality of treatment, the results continue to encourage us in its use.

Post-obstructive diuresis

Massive diuresis after relief of urinary tract obstruction has been divided into 3 categories: 1) salt, 2) urea and 3) water. Measurements of the urinary electrolytes and urine osmolality establish the character of the diuresis and facilitate in the fluid management of these patients. A clinical example of the 2 most common varieties, salt and urea, is presented in conjuction with the method of fluid replacement.

Blood urea nitrogen and serum creatinine. Physiology and interpretations

Any elevations in levels of blood urea nitrogen and/or serum creatinine do not necessarily indicate structural renal disease. Conversely, blood urea nitrogen or serum creatinine values, which appear to be within the range of normal, do not by themselves rule out significant reduction in glomerular filtration rate. Any interpretation of the blood levels of these two substances must be done with the awareness that a variety of extrarenal factors can affect them. The blood urea nitrogen to serum creatinine ratio can be a valuable tool in the determination or renal functional and structural integrity.

Ureteral replacements

The clinical necessities of replacing all or part of the diseased or destroyed ureter have plagued surgeons for many years. In the past seventy years more than 100 surgical techniques have been described for ureteral replacement. Methods of replacement have fallen into four categories; nonbiologic substitutes, pedicle grafts, free grafts, and implantation and diversion. This review discusses the history and present status, and presents a look to the future in the surgery of ureteral replacement.