Development of spinning-disk solid sample delivery system for high-repetition rate x-ray free electron laser experiments

X-ray free-electron lasers (XFELs) deliver intense x-ray pulses that destroy the sample in a single shot by a Coulomb explosion. Experiments using XFEL pulse trains or the new generation of high-repetition rate XFELs require rapid sample replacement beyond those provided by the systems now used at low repletion-rate XFELs. We describe the development and characterization of a system based on a spinning disk to continuously deliver a solid sample into an XFEL interaction point at very high speeds. We tested our system at the Linac Coherent Light Source and European XFEL hard x-ray nano-focus instruments, employing it to deliver a 25 μm copper foil sample, which can be used as a gain medium for stimulated x-ray emission for the proposed x-ray laser oscillator.

Patient navigation to improve diabetes outpatient care at a safety-net hospital: a retrospective cohort study

BACKGROUND

Recent emphasis on value based care and population management, such as Accountable Care Organizations in the United States, promote patient navigation to improve the quality of care and reduce costs. Evidence supporting the efficacy of patient navigation for chronic disease care is limited. The objective of this study was to evaluate the effect of a patient navigation program on medical and administrative outcomes among patients with diabetes in an urban, safety-net hospital clinic setting.

METHODS

A retrospective cohort study with pre- and post-intervention periods was conducted. Eligible patients were those with A1C ≥ 8.5% and at least one appointment no-show in the previous 12 months. The intervention and reference groups were balanced on observed characteristics and baseline outcome levels using propensity score matching. The effect of patient navigation was isolated using the difference-in-differences approach. Primary outcomes were A1C, low-density lipoprotein cholesterol, triglycerides, random urine microalbumin, the number of scheduled appointments, clinic visits, emergency visits, and inpatient stays, and the percentage of arrivals, cancellations, and no-shows to scheduled appointments.

RESULTS

Of 797 eligible patients, 328 entered the navigation program. Matching reduced the sample size to 392 individuals (196 in each group). Patient navigation resulted in improved A1C (-1.1 percentage points; p < .001), more scheduled appointments (+ 5.3 per year; p < .001), more clinic visits (+6.4 per year; p < .001), more arrivals to scheduled appointments (+7.4 percentage points; p = .009) and fewer no-shows (-9.8 percentage points; p < .001).

CONCLUSIONS

Navigation was associated with improved glycemic control and better clinic engagement among patients with diabetes. Further research is important to identify what features of navigation in diabetes care are critical to achieving success and to understand navigators' role in other settings.

An amylin analog used as a challenge test for Alzheimer's disease

INTRODUCTION

Preclinical studies demonstrate the potential of amylin in the diagnosis of Alzheimer's disease (AD). We aimed to lay the foundation for repurposing the amylin analog and a diabetes drug, pramlintide, for AD in humans.

METHODS

We administered a single subcutaneous injection of 60 μg of pramlintide to nondiabetic subjects under fasting conditions.

RESULTS

None of the participants developed hypoglycemia after the injection of pramlintide. The pramlintide challenge induced a significant surge of amyloid-β peptide and a decrease in total tau in the plasma of AD subjects but not in control participants. The pramlintide injection provoked an increase in interleukin 1 receptor antagonist and a decrease in retinol-binding protein 4, which separates AD subjects from control subjects.

DISCUSSION

Pramlintide use appeared to be safe in the absence of diabetes. The biomarker changes as a result of the pramlintide challenge, which distinguished AD from control subjects and mild cognitive impairment.

Plasma Amylin and Cognition in Diabetes in the Absence and the Presence of Insulin Treatment

Background

Plasma amylin is positively associated with cognitive function in humans. Amylin treatment improves memory in Alzheimer’s mouse models. However, the relationship between plasma amylin, diabetes and cognition is not clear.

Objectives

In this study we examined the concentration of plasma amylin, its relationship with diabetes and cognition.

Material and Method

A cross-sectional, homebound elderly population with data of plasma amylin under fasting condition and cognitive measurements was used.

Results

We found that subjects with a long and chronic duration of diabetes were more likely to take insulin treatment and have reduced secretion of amylin. Compared to non-diabetics, diabetic subjects without insulin treatment had a higher concentration, but those with insulin treatment had a lower concentration, of plasma amylin [median (Q1, Q3): 20 (11.0, 36.2) vs. 25.2 (13.2, 50.6) vs. 15.0 (4.9, 33.8), p<0.0001]. In the whole sample vs. in the absence of diabetes, plasma amylin was positively associated with logical memory delayed recall (β= +0.61, SE=0.25, p=0.02 vs. β=+0.80, SE=0.33, p=0.02) and block design (β=+0.62, SE=0.24, p=0.009 vs. β=+0.93, SE=0.31, p=0.003), and negatively associated with Trailmaking A scores (β= −6.21, SE=1.55, p<0.0001 vs. β=−7.51, SE=1.95, p=0.0001) and Trailmaking B (β= −4.32, SE=2.13, p=0.04 vs. β= −5.86, SE=2.73, p=0.04). All these relationships disappeared in the presence of diabetes regardless the treatment.

Conclusion

This study suggests that secretion of amylin by pancreas compensates and then deteriorates depending on the duration of diabetes. Amylin’s activities for cognition are impaired in the presence of diabetes.

Positive association between plasma amylin and cognition in a homebound elderly population

Our recent study reported that amylin, a pancreatic peptide that readily crosses the blood-brain barrier, improves learning and memory in Alzheimer's disease mouse models. However, the relationship between peripheral amylin and cognition in humans is unknown. In this follow-up study, using a cross-sectional, homebound elderly population, improvement in cognitive function with increasing quartiles of plasma amylin was suggested by positive association with verbal memory (p = 0.0002) and visuoconstruction tasks (p = 0.004), and inverse association with timed measures of attention (p < 0.0001) and executive function (p = 0.04). After adjusting for demographic information, apolipoprotein E4 allele, diabetes, stroke, kidney function, and lipid profile, log10 of plasma amylin remained associated with these cognitive domains. In contrast, plasma amyloid-β peptide was not associated with these specific cognitive domains. Our study suggests that peripheral amylin may be protective for cognitive decline, especially in the domains affected by Alzheimer's disease.

Hypoglycemia and diabetes: a report of a workgroup of the American Diabetes Association and the Endocrine Society

OBJECTIVE

To review the evidence about the impact of hypoglycemia on patients with diabetes that has become available since the past reviews of this subject by the American Diabetes Association and The Endocrine Society and to provide guidance about how this new information should be incorporated into clinical practice.

PARTICIPANTS

Five members of the American Diabetes Association and five members of The Endocrine Society with expertise in different aspects of hypoglycemia were invited by the Chair, who is a member of both, to participate in a planning conference call and a 2-day meeting that was also attended by staff from both organizations. Subsequent communications took place via e-mail and phone calls. The writing group consisted of those invitees who participated in the writing of the manuscript. The workgroup meeting was supported by educational grants to the American Diabetes Association from Lilly USA, LLC and Novo Nordisk and sponsorship to the American Diabetes Association from Sanofi. The sponsors had no input into the development of or content of the report.

EVIDENCE

The writing group considered data from recent clinical trials and other studies to update the prior workgroup report. Unpublished data were not used. Expert opinion was used to develop some conclusions.

CONSENSUS PROCESS

Consensus was achieved by group discussion during conference calls and face-to-face meetings, as well as by iterative revisions of the written document. The document was reviewed and approved by the American Diabetes Association's Professional Practice Committee in October 2012 and approved by the Executive Committee of the Board of Directors in November 2012 and was reviewed and approved by The Endocrine Society's Clinical Affairs Core Committee in October 2012 and by Council in November 2012.

CONCLUSIONS

The workgroup reconfirmed the previous definitions of hypoglycemia in diabetes, reviewed the implications of hypoglycemia on both short- and long-term outcomes, considered the implications of hypoglycemia on treatment outcomes, presented strategies to prevent hypoglycemia, and identified knowledge gaps that should be addressed by future research. In addition, tools for patients to report hypoglycemia at each visit and for clinicians to document counseling are provided.

Hypoglycemia and diabetes: a report of a workgroup of the American Diabetes Association and the Endocrine Society

OBJECTIVE

To review the evidence about the impact of hypoglycemia on patients with diabetes that has become available since the past reviews of this subject by the American Diabetes Association and The Endocrine Society and to provide guidance about how this new information should be incorporated into clinical practice.

PARTICIPANTS

Five members of the American Diabetes Association and five members of The Endocrine Society with expertise in different aspects of hypoglycemia were invited by the Chair, who is a member of both, to participate in a planning conference call and a 2-day meeting that was also attended by staff from both organizations. Subsequent communications took place via e-mail and phone calls. The writing group consisted of those invitees who participated in the writing of the manuscript. The workgroup meeting was supported by educational grants to the American Diabetes Association from Lilly USA, LLC and Novo Nordisk and sponsorship to the American Diabetes Association from Sanofi. The sponsors had no input into the development of or content of the report.

EVIDENCE

The writing group considered data from recent clinical trials and other studies to update the prior workgroup report. Unpublished data were not used. Expert opinion was used to develop some conclusions.

CONSENSUS PROCESS

Consensus was achieved by group discussion during conference calls and face-to-face meetings, as well as by iterative revisions of the written document. The document was reviewed and approved by the American Diabetes Association's Professional Practice Committee in October 2012 and approved by the Executive Committee of the Board of Directors in November 2012 and was reviewed and approved by The Endocrine Society's Clinical Affairs Core Committee in October 2012 and by Council in November 2012.

CONCLUSIONS

The workgroup reconfirmed the previous definitions of hypoglycemia in diabetes, reviewed the implications of hypoglycemia on both short- and long-term outcomes, considered the implications of hypoglycemia on treatment outcomes, presented strategies to prevent hypoglycemia, and identified knowledge gaps that should be addressed by future research. In addition, tools for patients to report hypoglycemia at each visit and for clinicians to document counseling are provided.

Protein kinase C-β contributes to impaired endothelial insulin signaling in humans with diabetes mellitus

BACKGROUND

Abnormal endothelial function promotes atherosclerotic vascular disease in diabetes. Experimental studies indicate that disruption of endothelial insulin signaling, through the activity of protein kinase C-β (PKCβ) and nuclear factor κB, reduces nitric oxide availability. We sought to establish whether similar mechanisms operate in the endothelium in human diabetes mellitus.

METHODS AND RESULTS

We measured protein expression and insulin response in freshly isolated endothelial cells from patients with type 2 diabetes mellitus (n=40) and nondiabetic controls (n=36). Unexpectedly, we observed 1.7-fold higher basal endothelial nitric oxide synthase (eNOS) phosphorylation at serine 1177 in patients with diabetes mellitus (P=0.007) without a difference in total eNOS expression. Insulin stimulation increased eNOS phosphorylation in nondiabetic subjects but not in diabetic patients (P=0.003), consistent with endothelial insulin resistance. Nitrotyrosine levels were higher in diabetic patients, indicating endothelial oxidative stress. PKCβ expression was higher in diabetic patients and was associated with lower flow-mediated dilation (r=-0.541, P=0.02). Inhibition of PKCβ with LY379196 reduced basal eNOS phosphorylation and improved insulin-mediated eNOS activation in patients with diabetes mellitus. Endothelial nuclear factor κB activation was higher in diabetes mellitus and was reduced with PKCβ inhibition.

CONCLUSIONS

We provide evidence for the presence of altered eNOS activation, reduced insulin action, and inflammatory activation in the endothelium of patients with diabetes mellitus. Our findings implicate PKCβ activity in endothelial insulin resistance.

High-order-harmonic generation and superradiance in a seeded free-electron laser

Higher order harmonic generation in a free-electron laser amplifier operating in the superradiant regime [R. H. Dicke, Phys. Rev. 93, 99 (1954).] has been observed. Superradiance has been induced by seeding a single-pass amplifier with the second harmonic of a Ti:sapphire laser, generated in a β-Barium borate crystal, at seed intensities comparable to the free-electron laser saturation intensity. Pulse energy and spectral distributions of the harmonics up to the 11th order have been measured and compared with simulations.

Self-amplified spontaneous emission free-electron laser with an energy-chirped electron beam and undulator tapering

We report the first experimental implementation of a method based on simultaneous use of an energy chirp in the electron beam and a tapered undulator, for the generation of ultrashort pulses in a self-amplified spontaneous emission mode free-electron laser (SASE FEL). The experiment, performed at the SPARC FEL test facility, demonstrates the possibility of compensating the nominally detrimental effect of the chirp by a proper taper of the undulator gaps. An increase of more than 1 order of magnitude in the pulse energy is observed in comparison to the untapered case, accompanied by FEL spectra where the typical SASE spiking is suppressed.

Experimental demonstration of emittance compensation with velocity bunching

In this Letter we report the first experiments aimed at the simultaneous demonstration of the emittance compensation process and velocity bunching in a high brightness electron source, the SPARC photoinjector in INFN-LNF. While a maximum compression ratio up to a factor 14 has been observed, in a particular case of interest a compression factor of 3, yielding a slice current of 120 A with less than 2 microm slice emittance, has been measured. This technique may be crucial in achieving high brightness beams in photoinjectors aiming at optimized performance of short wavelength single-pass free electron lasers or other advanced applications in laser-plasma accelerators.

Direct measurement of the double emittance minimum in the beam dynamics of the sparc high-brightness photoinjector

In this Letter we report the first experimental observation of the double emittance minimum effect in the beam dynamics of high-brightness electron beam generation by photoinjectors; this effect, as predicted by the theory, is crucial in achieving minimum emittance in photoinjectors aiming at producing electron beams for short wavelength single-pass free electron lasers. The experiment described in this Letter was performed at the SPARC photoinjector site, during the first stage of commissioning of the SPARC project. The experiment was made possible by a newly conceived device, called an emittance meter, which allows a detailed and unprecedented study of the emittance compensation process as the beam propagates along the beam pipe.

Improving outcomes for patients with diabetes using Joslin Diabetes Center's Registry and Risk Stratification system

Joslin Diabetes Center's Registry and Risk Stratification System collects data on key measures of diabetes care and provides diabetes decision support to primary care providers. Specifically, this system identifies high-risk patients in a population, recommends patient-specific interventions based on Joslin's clinical guidelines, and reports a clinic's process and quality metrics for benchmarking and regional comparisons. This article describes Joslin's system and its impact on the quality of diabetes care in the primary care setting.

Properties of the ultrashort gain length, self-amplified spontaneous emission free-electron laser in the linear regime and saturation

VISA (Visible to Infrared SASE Amplifier) is a high-gain self-amplified spontaneous emission (SASE) free-electron laser (FEL), which achieved saturation at 840 nm within a single-pass 4-m undulator. The experiment was performed at the Accelerator Test Facility at BNL, using a high brightness 70-MeV electron beam. A gain length shorter than 18 cm has been obtained, yielding a total gain of 2 x 10(8) at saturation. The FEL performance, including the spectral, angular, and statistical properties of SASE radiation, has been characterized for different electron beam conditions. Results are compared to the three-dimensional SASE FEL theory and start-to-end numerical simulations of the entire injector, transport, and FEL systems. An agreement between simulations and experimental results has been obtained at an unprecedented level of detail.

Capillary-elastic instabilities of liquid-lined lung airways

To model the competition between capillary and elastic forces in controlling the shape of a small lung airway and its interior liquid lining, we compute the equilibrium configurations of a liquid-lined, externally pressurized, buckled elastic tube. We impose axial uniformity and assume that the liquid wets the tube wall with zero contact angle. Non-zero surface tension has a profound effect on the tube's quasi-steady inflation-deflation characteristics. At low liquid volumes, hysteresis arises through two distinct mechanisms, depending on the buckling wavenumber. Sufficient compression always leads to abrupt and irreversible collapse and flooding of the tube; flooding is promoted by increasing liquid volumes or surface tension. The model captures mechanisms whereby capillary-elastic instabilities can lead to airway closure.

Fundamental and harmonic microbunching in a high-gain self-amplified spontaneous-emission free-electron laser

Electron beam microbunching in both the fundamental and second harmonic in a high-gain self-amplified spontaneous emission free-electron laser (SASE FEL) was experimentally characterized using coherent transition radiation. The microbunching factors for both modes (b(1) and b(2)) approach unity, an indication of FEL saturation. These measurements are compared to the predictions of FEL simulations. The simultaneous capture of the microbunching and SASE radiation for individual micropulses correlate the longitudinal electron beam structure with the FEL gain.

Experimental characterization of nonlinear harmonic radiation from a visible self-amplified spontaneous emission free-electron laser at saturation

Nonlinear harmonic radiation was observed using the VISA self-amplified, spontaneous emission (SASE) free-electron laser (FEL) at saturation. The gain lengths, spectra, and energies of the three lowest SASE FEL modes were experimentally characterized. The measured nonlinear harmonic gain lengths and center spectral wavelengths decrease with harmonic number, n, which is consistent with nonlinear harmonic theory. Both the second and third nonlinear harmonics energies are about 1% of the fundamental energy. These experimental results demonstrate for the first time the feasibility of using nonlinear harmonic SASE FEL radiation to produce coherent, femtosecond x rays.

Pioglitazone hydrochloride in combination with metformin in the treatment of type 2 diabetes mellitus: a randomized, placebo-controlled study. The Pioglitazone 027 Study Group

BACKGROUND

Their complimentary mechanisms of action suggest that a combination of pioglitazone hydrochloride and metformin may have clinically beneficial effects in the treatment of patients with type 2 diabetes.

OBJECTIVE

This study was undertaken to assess the efficacy and tolerability of pioglitazone in combination with metformin in patients with type 2 diabetes mellitus.

METHODS

This was a 16-week, double-blind study with the option of enrollment in a separate open-ended, open-label study. It included patients with poorly controlled diabetes mellitus (glycated hemoglobin [HbA1c] > or =8.0%, fasting C-peptide >1.0 ng/mL) who had been receiving a stable regimen of metformin for > or =30 days. Patients with diabetic retinopathy, nephropathy, or neuropathy; impaired liver or kidney function; or unstable cardiovascular or cerebrovascular conditions were excluded. Patients were randomized to receive once-daily pioglitazone 30 mg + metformin or placebo + metformin. Patients in the open-label extension received pioglitazone 30 mg (with optional titration to 45 mg) + metformin.

RESULTS

Three hundred twenty-eight patients were randomized to treatment (168 pioglitazone + metformin, 160 placebo + metformin), and 249 completed the study. Of these, 154 elected to enter the open-label extension study. Patients' mean age was 56 years; most (84%) were white and slightly more than half (57%) were male. Patients receiving piogli- tazone 30 mg + metformin had statistically significant mean decreases in HbA1c (-0.83%) and fasting plasma glucose (FPG) levels (-37.7 mg/dL) compared with placebo + metformin (P < or = 0.05). Decreases in FPG levels occurred as early as the fourth week of therapy, the first time point at which FPG was measured. The pioglitazone + metformin group had significant mean percentage changes in levels of triglycerides (-18.2%) and high-density lipoprotein cholesterol (+8.7%) compared with placebo + metformin (P < or = 0.05). Mean percentage increases were noted in low-density lipoprotein cholesterol levels (7.7%, pioglitazone + metformin; 11.9%, placebo + metformin) and total cholesterol (4.1%, pioglitazone + metformin; 1.1%, placebo + metformin), with no significant differences between groups. In the extension study, patients treated with open-label pioglitazone + metformin for 72 weeks had mean changes from baseline of -1.36% in HbA1c and -63.0 mg/dL in FPG. The incidence of adverse events was similar in both groups. Throughout the study, no patient in either treatment group had an alanine aminotransferase (ALT) value > or =3 times the upper limit of normal, a commonly used marker of potential liver damage. Thus, no evidence of drug-induced hepatotoxicity or drug-induced elevations in serum ALT was observed.

CONCLUSIONS

In this study in patients with type 2 diabetes mellitus, pioglitazone + metformin significantly improved HbA1c and FPG levels, with positive effects on serum lipid levels and no evidence of drug-induced hepatotoxicity. These effects were maintained for >1.5 years, including the open-label extension.

Couple-friendly services in a metropolitan sexually transmitted disease clinic: views of clients and providers

CONTEXT

Clients making clinic visits related to reproductive health might benefit from participation with their partner. There is little information available, however, on whether either clients themselves or clinic staff would feel comfortable with such a possibility.

METHODS

The Multnomah County Health Department Sexually Transmitted Disease Clinic in Portland, Oregon, conducted a survey of 237 new clients in June 1994 to assess clients' and providers' responses to the idea of offering couple visits.

RESULTS

Twenty-six percent of female clients and 16% of male clients were accompanied by their partner on their visit to the clinic. Eighty-seven percent of all clients favored the clinic's offering couple visits, 5% opposed the concept and 8% were undecided. Fifty-four percent would have wanted their partner to be with them during their present visit if this choice had been offered, and 62% would want their partner to join them in follow-up couple visits if this were recommended by their provider. Seventy-one percent had already discussed with their partner the reason for their immediate clinic visit, and 88% expected to discuss the visit with their partner afterward. Attitudes toward couple services were similar for male and female clients and did not vary by race or ethnicity. For more than one-fifth of clients, clinic staff reported that they would not recommend couple visits; however, many of these clients reported that they would prefer being accompanied by their partner.

CONCLUSIONS

Appropriately designed couple-friendly options are likely to be generally accepted and moderately utilized by clients of varying backgrounds. Clinic staff may be more reluctant to involve clients' partners than the clients are themselves, however.

Novel mutations and a mutational hotspot in the MODY3 gene

Maturity-onset diabetes of the young 3 (MODY3) is a type of NIDDM caused by mutations in the transcription factor hepatocyte nuclear factor-1alpha (HNF-1alpha) located on chromosome 12q. We have identified four novel HNF-1alpha missense mutations in MODY3 families. In four additional and unrelated families, we observed an identical insertion mutation that had occurred in a polycytidine tract in exon 4. Among those families, one exhibited a de novo mutation at this location. We propose that instability of this sequence represents a general mutational mechanism in MODY3. We observed no HNF-1alpha mutations among 86 unrelated late-onset diabetic patients with relative insulin deficiency. Hence mutations in this gene appear to be most strongly associated with early-onset diabetes.

Starch peritonitis following peritoneal dialysis

Peritoneal dialysis is used frequently in the treatment of patients having renal failure. A 43-year-old patient developed acute abdominal symptoms 7 days after completion of peritoneal dialysis. Celiotomy demonstrated peritonitis with presence of starch powder. Resolution occurred rapidly after removal of the powder. Starch peritonitis after peritoneal dialysis can be obviated by careful washing of gloves. It can be managed without operative intervention. Peritonitis due to starch dusting powder can occur as a complication of peritoneal dialysis.

Risk for alcoholism and methadone treatment. A longitudinal study

To investigate the relationship between methadone and alcohol abuse, 60 male veteran narcotic addicts entering a methadone maintenance program were divided into either a problem drinker group (N = 21) or a normal drinker group (N = 39) based on their drinking histories and Breathalyzer tests at admission. Their performance was monitored throughout methadone treatment. Results showed no systematic changes in alcohol use. Problem drinkers tended to be involved in more criminal activity, showed more evidence of depression and anxiety, and were more likely to continue abuse of illicit drugs. These results suggest that stabilization was not etiologically associated with alcohol abuse.

Intrarenal hemodynamics and renal function in postobstructive uropathy

Impairment of renal function was noted after release of 24 hr of unilateral (UUO) and bilateral (BUO) ureteral obstruction. After release of obstruction fractional sodium excretion was identical in both obstructed and intact kidney of UUO rats, whereas massive natriuresis occurred in BUO rats. Renal blood flow in BUO rats, determined by the microsphere method after released of 24 h of obstruction, was approximately 60 per cent of control values. Mean renal blood flow of the obstructed kidney of UUO rats after release of obstruction was 78 per cent of the mean renal blood flow of the contralateral unobstructed kidney. No redistribution of intrarenal blood flow was noted in UUO and BUO rats. Filtration fractions of obstructed kidneys from BUO and UUO rats after release of obstruction were lower than those of controls, suggesting that preglomerular vasoconstriction is primarily involved in the reduction of glomerular filtration rate.

Effect of minoxidil on blood pressure and hemodynamics in severe hypertension

Eighteen patients with diastolic hypertension (100 to 120 mm Hg), in addition to propranolol, 160 mg daily, and hydrochlorothiazide, 100 mg daily, received progressively increased doses of either minoxidil or placebo in a double-blind crossover study. With minoxidil (average dose 19.7 mg) blood pressure decreased from 165/109 to 138/89 mm Hg without the appearance of orthostatic hypotension. Hypertrichosis and fluid retention did occur, with an average weight gain of 1.8 kg, concomitant with an increased plasma volume. Pulse rate and cardiac output increased; no significant changes were observed in plasma renin activity, renal plasma flow, glomerular filtration rate or excretion of catecholamines or aldosterone. Minoxidil appears to be a useful antihypertensive drug for treating patients who do not respond adequately to therapy with diuretic and beta adrenergic blocking agents.

Intrarenal hemodynamics and ureteral pressure during ureteral obstruction

Renal blood flow was measured in bilateral ureteral obstruction (BUO) and unilateral ureteral (UUO) obstruction. Renal blood flow of BUO and UUO rats before release of 24-hr obstruction was approximately 69 per cent and 77 per cent of control values, respectively. No redistribution of intrarenal blood flow was noted in UUO and BUO rats. Prerelease ureteral pressure of BUO rats (27.6 +/- 1.60 mm Hg) was significantly higher than that of UUO rats (14.4 +/- 1.30 mm Hg, P less than 0.001). Although the blood urea nitrogen of UUO rats with urine reinfusion was similar to that of BUO rats, the ureteral pressure was 14.8 +/- 1.93 mm Hg. Therefore, the higher ureteral pressure of BUO rats is not due to elevation of blood urea nitrogen. It is concluded that decreased renal blood flow during obstruction and high ureteral pressure may result in more severe tubular damage in BUO than in UUO. The decreased renal perfusion is probably due to changes in intrarenal vascular tone rather than due to intersitial pressure.

Renal hemodynamics in HgCl2-induced acute renal failure

Renal blood flow (RBF), outer cortical blood flow (OC-rbf) and inner cortical blood flow were determined by the microsphere method in water-drinking rats and chronic saline-drinking rats at 3, 12 and 24 h after injection of HgCl2, 4.7 mg/kh body weight. RFB and OC-rbf were decreased in both groups at 3 h post HgCl2 injection. Persistent reduction of OC-rbf was noted in water-drinking rats at 12 and 24 h post HgCl2 even though the total RBF returned to normal by 24 h. These parameters were normal in chronic saline-drinking rats. Despite normal RBF in water-drinking and saline-drinking rats, serum creatinines were still signigicantly elevated 24 h post HgCl2. Therefore, alterations in total renal perfusion do not entirely account for the decreased renal function that occurs under these circumstances.

Sequential renal transplants: some surgical and immunological implications on management of the first homograft

Experience with 35 second grafts included in a total number of 310 renal transplants was analyzed to identify factors associated with success. The 2 year life-table renal survival rate of sequential cadaveric grafts is 42 percent compared in 54 percent for primary cadaveric grafts. The 2 year life-table patient survival rate for the same group is 68 percent compared to 72 percent for single cadaveric homotransplants. Twenty-one of 30 patients tested in the interval between grafts developed cytotoxic antibodies to greater than 5 percent of a random panel of cells; 43 percent of these kidneys functioned at least one year; 65 percent functioned for one year or more if the cytotoxicity was 5 percent or less. If the first graft functioned greater than 3 months, the second had a 67 percent chance of functioning for one year; if less than 3 months, the second had a 45 percent one year function rate. Removal of the first transplant at time of second transplantation resulted in an 88 percent one year life-table survival rate of the second kidney in nine patients. Removal prior to second transplantation resulted in a 25 percent one year survival rate in 23 patients. To further evaluate this significant finding, data was obtained through the American College of Surgeons/National Institutes of Health (ACS/NIH) Organ Transplant Registry from five major transplant centers. Thirty-two patients had their first graft removed at time of second transplantation with a 52 percent one year life-table kidney survival rate vs. 29 percent if the first were removed more than 90 days prior to second grafting. Statistical analysis shows this to be significant at the 95 percent confidence level.