Magnetization transfer ratio: a quantitative imaging biomarker for 5q spinal muscular atrophy.

BACKGROUND AND PURPOSE: We quantified peripheral nerve lesions in adults with 5q-linked spinal muscular atrophy (SMA) type 3 by analysing the magnetization transfer ratio (MTR) of the sciatic nerve, and tested its potential as a novel biomarker for macromolecular changes. METHODS: Eighteen adults with SMA 3 (50% SMA 3a, 50% SMA 3b) and 18 age-/sex-matched healthy controls prospectively underwent magnetization transfer contrast imaging in a 3-Tesla magnetic resonance scanner. Two axial three-dimensional gradient echo sequences, with and without an off-resonance saturation rapid frequency pulse, were performed at the right distal thigh. Sciatic nerve regions of interest were manually traced on 10 consecutive axial slices in the images generated without off-resonance saturation, and then transferred to corresponding slices generated by the sequence with the off-resonance saturation pulse. Subsequently, MTR and cross-sectional areas (CSAs) of the sciatic nerve were analysed. In addition, detailed neurologic, physiotherapeutic and electrophysiologic examinations were conducted in all patients. RESULTS: Sciatic nerve MTR and CSA reliably differentiated between healthy controls and SMA 3, 3a or 3b. MTR was lower in the SMA 3 (P < 0.0001), SMA 3a (P < 0.0001) and SMA 3b groups (P = 0.0020) than in respective controls. In patients with SMA 3, MTR correlated with all clinical scores, and arm nerve compound motor action potentials (CMAPs). CSA was lower in the SMA 3 (P < 0.0001), SMA 3a (P < 0.0001) and SMA 3b groups (P = 0.0006) than in controls, but did not correlate with clinical scores or electrophysiologic results. CONCLUSIONS: Magnetization transfer ratio is a novel imaging marker that quantifies macromolecular nerve changes in SMA 3, and positively correlates with clinical scores and CMAPs.

Gas chromatographic column for the viking 1975 molecular analysis experiment.

A gas chromatographic column has been developed for use in the remote analysis of the martian surface. The column, which utilizes a liquid-modified organic adsorbent (Tenax) as the stationary phase, provides efficient transmission and resolution of nanogram quantities of organic materials in the presence of millionfold excesses of water and carbon dioxide.

Recognition of paleobiochemicals by a combined molecular sulfur and isotope geochemical approach.

Study of organic matter in immature sediments from a Messinian evaporitic basin shows that consideration of structures, modes of occurrence, and carbon isotopic compositions of free and sulfur-bound carbon skeletons allow identification of biochemical precursors. Detailed information concerning biotic communities present during deposition of sediments can be retrieved in this way. Moreover, unprecedented biochemicals were recognized; these extend the horizon of biomarker geochemistry.

Organic analysis of the returned lunar sample.

Lunar fines have been examined for organic compounds by crushing, programmed heating, hydrofluoric acid etching, and solvent extraction. Products were examined by mass spectroscopy. A variety of small organic molecules, including methane and other hydrocarbons, accompanied the release of the rare gases when the sample was heated in a stepwise fashion to 900 degrees C under vacuum. Methane is more abundant (abundance on the order of 1 part per million) than argon in the matrix-entrapped gases liberated by hydrofluoric acid etching of lunar fines. Methane is also present in a dark portion of the gas-rich meteorite Kapoeta.

Toll-like receptors and inflammation in metabolic neuropathy; a role in early versus late disease?

Neuropathy is a common, morbid complication of the metabolic syndrome, prediabetes, and diabetes. Recent studies have indicated a potential role for the immune system in the development of neuropathy. In particular, toll-like receptors (TLR) 2 and 4 have been linked to metabolic dysfunction, and blocking TLR4 is proposed as a treatment for neuropathic pain. In the current study, we investigated the role of the immune system, particularly TLRs 2 and 4, in the pathogenesis and progression of neuropathy. Sural or sciatic nerve gene expression arrays from humans and murine neuropathy models of prediabetes and diabetes were first analyzed to identify differentially expressed TLR2- and TLR4-associated genes within the KEGG (Kyoto Encyclopedia of Genes and Genomes) database. We observed that genes associated with TLRs 2 and 4, particularly lipopolysaccharide binding protein (LPB) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit beta (PIK3CB), were dysregulated across species and across multiple murine models of prediabetic and diabetic neuropathy. To further understand the role of these pathways in vivo, TLR 2 and 4 global knockout mice placed on a 60% high fat diet (HFD-TLR2/4-/-) were compared with wild type (WT) mice on a high fat diet (HFD-WT) and WT controls on a standard diet (CON). Mice then underwent metabolic, neuropathic, and immunological phenotyping at two time points to assess the impact of TLR signaling on neuropathy and immunity during metabolic dysfunction over time. We found that HFD-TLR2/4-/- and HFD-WT mice weighed more than CON mice but did not have increased fasting blood glucose levels. Despite normal blood glucose levels, HFD-TLR2/4-/- mice eventually developed neuropathy at the later time point (28 wks of age) but were somewhat protected from neuropathy at the early time point (16 wks of age) as measured by shorter hind paw withdraw latencies. This is in contrast to HFD-WT mice which developed neuropathy within 11 wks of being placed on a high fat diet and were neuropathic by all measures at both the early and late time points. Finally, we immunophenotyped all three mouse groups at the later time point and found differences in the number of peripheral blood Ly6C-myeloid cells as well as F4/80+ expression. These results indicate that TLR signaling influences early development of neuropathy in sensory neurons, potentially via immune modulation and recruitment.

New inhibitors of glycogen phosphorylase as potential antidiabetic agents.

The protein glycogen phosphorylase has been linked to type 2 diabetes, indicating the importance of this target to human health. Hence, the search for potent and selective inhibitors of this enzyme, which may lead to antihyperglycaemic drugs, has received particular attention. Glycogen phosphorylase is a typical allosteric protein with five different ligand binding sites, thus offering multiple opportunities for modulation of enzyme activity. The present survey is focused on recent new molecules, potential inhibitors of the enzyme. The biological activity can be modified by these molecules through direct binding, allosteric effects or other structural changes. Progress in our understanding of the mechanism of action of these inhibitors has been made by the determination of high-resolution enzyme inhibitor structures (both muscle and liver). The knowledge of the three-dimensional structures of protein-ligand complexes allows analysis of how the ligands interact with the target and has the potential to facilitate structure-based drug design. In this review, the synthesis, structure determination and computational studies of the most recent inhibitors of glycogen phosphorylase at the different binding sites are presented and analyzed.

Nonphotochemical hole-burning study of selectively stained normal and cancerous human ovarian tissues.

Results are presented of nonphotochemical hole-burning (HB) experiments on cancerous ovarian and analogous normal peritoneal in vitro tissues stained with the mitochondrial-selective dye rhodamine 800. A comparison of fluorescence excitation spectra, hole-growth kinetics data, and external electric field (Stark) effects on the shape of spectral holes burned in cancerous and normal tissues stained with rhodamine 800 revealed significant differences only in the dipole moment change (fDeltamu) measured by a combination of HB and Stark spectroscopies. It is shown that the permanent dipole moment change for the S0--> S1 transition of the rhodamine 800 molecules in cancerous tissue is higher than that of normal tissue by a factor of about 1.4. The finding is similar to the HB results obtained earlier for human ovarian surface epithelial cell lines, i.e., OV167 carcinoma and OSE(tsT)-14 normal cells stained with the same mitochondria-specific dye (Walsh et al. Biophys. J. 2003, 84, 1299). We propose that the observed difference in the permanent dipole moment change in cancerous ovarian tissue is related to a modification in mitochondrial membrane potential.

Fulminant lupus pneumonitis with acute renal failure and RBC aplasia. Successful management with plasmapheresis and immunosuppression.

Acute interstitial pneumonitis is a well-recognized, although rare, complication of systemic lupus erythematosus (SLE) that has been associated with a poor prognosis. Fulminant lupus pneumonitis, acute renal failure, and RBC hypoplasia occurred in a 14-year-old girl. The patient's condition was managed with large-volume plasmapharesis, dialysis, and immunosuppressive therapy. Her respiratory, renal, and hematologic changes all resolved, and response was maintained with cyclophosphamide and prednisolone therapy. Although serologic evidence of SLE persisted, clinically, the patient was well four years after the initial appearance of SLE. There are several acute pulmonary manifestations of SLE, and plasmapheresis may be useful in the management of some of these conditions.

The relative role of neutrophils and platelets in the local accumulation of circulating lymphocytes at sites of ionophore A23187 inoculation.

The early cellular infiltrate at inflammatory sites consists predominantly of neutrophils and cells of the monocyte/macrophage lineage. The mechanism by which circulating, unsensitized lymphocytes accumulate at sites of inflammation is unknown. The pattern of accumulation of 111indium-labeled circulating thymocytes in response to local injections of the ionophore A23187 was studied and compared with the pattern of (125)iodinated albumin accumulation as a measure of vascular permeability. The kinetics of thymocyte accumulation differed from those of vascular permeability. Sublethal total-body irradiation (750 rads) markedly decreased thymocyte accumulation but had little effect on vascular permeability. Irradiation of the local site alone had no effect. T lymphocyte, T lymphoblast, and platelet accumulation generally followed the same pattern as thymocytes. Intravenous injection of neutrophils, but not platelets, partially restored lymphocyte accumulation in vivo in irradiated mice via a pathway involving the circulating neutrophil, and seemed to be independent of changes in vascular permeability.

The development of proteinuria and focal-segmental glomerulosclerosis in recipients of pediatric donor kidneys.

Several reports in animals, and sporadic case reports in humans, have suggested that kidneys with decreased nephron mass may be more susceptible to the development of focal-segmental glomerosclerosis. This prompted a reexamination of our previously reported group of pediatric donor-adult recipient renal transplant combinations. Data were analyzed from 31 adult recipients who had received renal transplants from cadaver pediatric donors (less than 6 years) with graft function for greater than 6 months and no evidence of chronic rejection. These were compared with a control group transplanted during the same period with adult donor kidneys. Immunosuppression consisted of azathioprine/prednisone or quadruple therapy in 16 and 15 patients respectively. End-stage renal disease (ESRD) was secondary to chronic glomerulonephritis (n = 9), diabetes mellitus (n = 6), polycystic kidney disease (n = 5), and miscellaneous causes (n = 11). Twenty patients had radiographic documentation of renal hypertrophy posttransplant. All patients had serial 24-hr urinalysis for protein and creatinine after transplantation during periods of stable renal function. Ten patients had renal biopsies performed at a mean time from transplant to biopsy of 10.4 +/- 1.6 months. Seven recipients had biopsies that revealed glomerulosclerosis at 13 +/- 6 months posttransplant. Protein excretion and serum creatinine in these patients were significantly higher than in control patients (1.6 +/- 0.37 vs. 0.49 +/- 0.15 g/24 hr and 1.96 +/- 0.11 vs. 1.64 +/- 0.09 mg%; P less than 0.03 and P less than 0.01, respectively). Only 3 of 25 control adult donor recipients developed proteinuria greater than 0.8 g/24 hr within 2 years of transplantation vs. 15/31 pediatric donor recipients. No correlations with the etiology of ESRD, age (greater than or less than 40 years), weight, sex, diabetes, hypertension, or the number of acute rejection episodes could be found. Our data suggest that adult recipients of pediatric donor renal transplants may be at greater risk for the development of glomerulosclerosis than those recipients receiving adult donor kidneys.

Pericarditis following renal transplantation.

We analyzed data on renal allograft recipients over a 27-year period in order to investigate the frequency, etiology, and outcome of pericarditis developing during the first two months following renal transplantation. Of the 1497 patients receiving renal transplants between 1963 and 1990, 34 patients developed 36 episodes of pericarditis and/or pericardial effusions, for an overall incidence of 2.4%. Pericarditis was attributed to uremia in 14 episodes, cytomegalovirus infection in three, both uremia and CMV infection in four, nonspecific bacterial infection in three, and tuberculosis and minoxidil therapy in one episode each. No etiologic diagnosis could be established in 10 episodes. No statistically significant differences were found between pericarditis and case-matched control patients considering demographic features, the number of immediately functioning grafts, the duration of posttransplant acute renal failure, the number of supportive dialysis days, pre- and postoperative CMV status of the patients, and pretransplant BUN and serum creatinine levels. There were more uremic-related complications (pulmonary edema, gastrointestinal bleeding, central nervous system symptoms) in the pericarditis group. Five allografts in the pericarditis group never functioned, versus only one in the control group. Three patients with pericarditis developed pericardial tamponade. Early diagnosis, close follow-up, and in the case of cardiac tamponade early invasive treatment, should improve the prognosis of this potentially life-threatening complication.

Soluble HLA class II concentrations in normal individuals and transplant recipients. Comparison with soluble HLA class I concentrations.

We developed an ELISA to quantify soluble HLA class II (S-HLA-II) in 702 sera obtained from normal subjects, patients with end-stage renal disease, and recipients of renal, hepatic, and cardiac transplants. Concentrations of S-HLA-II were detectable in 124 of 126 normal individuals. The distribution of normal values described a monophasic curve with a skewed distribution. In transplant recipients, there were no differences between preoperative and posttransplant values, but values in liver patients were significantly higher than in kidney patients, and values for heart patients were lowest of all groups. There were periodic variations in concentrations in individual patients, but these were unrelated to rejection, infection, or any other apparent clinical event. S-HLA-II was consistently present in the urine. All of these observations contrast with previous observations concerning soluble HLA class I (S-HLA-I) molecules, which were almost the precise reverse. It seems likely that these clear differences in S-HLA-II and S-HLA-I concentrations relate to different physiologic processes in either production, function, or elimination.

The use of single pediatric cadaver kidneys for transplantation.

We have reviewed our experience with 126 single pediatric cadaver kidneys (donor ages 9 months to 16 years) transplanted over a 10-year period. There were 17 donors aged 0-2 years, 55 donors aged 0-6 years, 34 donors aged 7-12 years, and 37 donors aged 13-16 years. One-year patient and graft survival was 88.2%/76.5%, 91%/74%,88.3%/69.1%, and 94.4%/80.6% for the respective groups. One-year patient and graft survival for an adult donor control group was 93%/69%. The percentage of recipients requiring dialysis in the early posttransplant period was 70.6%, 54.5%, 52.9%, 51.4%, and 52.4% for all groups, respectively. The time to reach a nadir creatinine was similar in all groups (24-30 days). While the functional outcome was comparable to cadaver transplantation utilizing adult donor kidneys, a higher incidence of infections and technical complications were encountered in the young-donor-age groups. Overall, there were 12 ureteral complications (8 fistulas, 4 stenoses), 3 bladder fistulas, and 4 renal artery stenoses. The urologic complication rate in kidneys from donors 0-2 years of age was 23.5% (all ureteral fistulas) versus 5% in the kidneys from adult donors. Only one graft was lost due to a technical complication. We conclude that, while cadaver kidneys from donors in the young age groups may be utilized successfully for transplantation, a higher incidence of urologic complications may be associated with their use. Careful harvesting and intraoperative techniques may minimize complications when utilizing kidneys from these donors.

Renal transplant calculi. A reevaluation of risks and management.

Between January 1977 and March 1988, 10 of 892 renal transplant recipients formed urinary tract calculi posttransplantation. The presenting symptoms were predominantly those of azotemia due to obstruction and/or hematuria. Factors predisposing to stone formation included a reconstructive urologic procedure at the time of transplantation (n = 4) or a surgical complication (n = 4), necessitating the placement of a ureteral stent and/or nephrostomy tube, secondary hyperparathyroidism (n = 5), hyperuricosuria (n = 4), and hypercalciuria (n = 1). Four patients passed their stones spontaneously; 1 patient underwent ureterolithotomy, 3 patients underwent endourologic stone extraction, 1 patient was treated with a combination of surgical and endourologic procedures, and 1 patient underwent extracorporeal shock wave lithotripsy as monotherapy. While the management of these patients can be challenging, awareness of predisposing factors, proper application of all currently available urologic techniques, and attention to certain guidelines of management can aid in minimizing morbidity from this rare urologic complication of renal transplantation.

Comparison of OKT3 with ALG for prophylaxis for patients with acute renal failure after cadaveric renal transplantation.

A randomized, prospective comparison of OKT3 vs. ALG (University of Minnesota) was performed in patients who had acute renal failure after a cadaver renal transplantation. Criteria for admission to the study were oliguria or increasing serum creatinine in the first 12 hr after renal transplantation. ALG or OKT3 was administered after randomization beginning 12-36 hours posttransplantation. There were no significant differences in age, sex, original disease, ischemia time, or HLA matching between groups. Graft survivals at 1 and 6 months were 84% and 84%, respectively for the ALG group. One- and 6-month graft survival for the OKT3 group was 88% and 84%, respectively. These differences were not statistically significant. The number of rejection episodes and the number of patients with rejection episodes were greater, and the time to first rejection was shorter in the OKT3 group compared with the ALG group, although none of these differences reached statistical significance. There were significantly less side effects in the ALG group compared with the OKT3 group (P less than .05). The greatest reductions in side effects were in fever and hypotension. Patients were monitored with flow cytometry analysis measuring the number of CD2 (T11) and CD3 (T3) cells to adjust the dose of both OKT3 and ALG. Starting doses were 10 mg/kg/day of ALG and 5 mg/day of OKT3. There were no significant differences in the incidence of infections (viral or bacterial) between the two groups. There were no rejection episodes during the prophylactic therapy with either ALG or OKT3. In summary, both ALG and OKT3 provided effective prophylaxis for patients with acute renal failure after renal transplantation. OKT3 was associated with a statistically significant increase in incidence of symptomatic side effects.

Effect of HLA matching on organ distribution among whites and African-Americans.

A total of 159 patients received renal cadaveric grafts under 2 different allocation systems. System 1, a local variance (i.e., a point system different from that of United Network for Organ Sharing [UNOS]), and system 2, the current UNOS point system, differed in the relative emphasis on waiting time and HLA match. The racial composition of the donor pools and recipient waiting lists was the same for both periods examined. The percentage of African-Americans transplanted did not differ significantly under the 2 allocation systems and, in fact, increased slightly, from 29.4% to 33.8%, under system 2, which attributed more weight to HLA match. A difference in the allocation of kidneys from African-American donors was seen. Under system 1, only 2 of 8 kidneys from African-American donors went to African-American recipients, while under system 2, 6 of 8 kidneys from African-American donors went to African-American recipients. These data suggest that the current UNOS point system does not provide any added disadvantage to non-whites and may, in fact, provide an incentive for minority groups to donate organs, in that HLA matching appears to promote intraracial transplantation.

Effects of tacrolimus on hyperlipidemia after successful renal transplantation: a Southeastern Organ Procurement Foundation multicenter clinical study.

BACKGROUND: Tacrolimus has been shown to have a less adverse effect on the lipid profiles of transplant patients when the drug is started as induction therapy. In order to determine the effect tacrolimus has on lipid profiles in stable cyclosporine-treated renal transplant patients with established hyperlipidemia, a randomized prospective study was undertaken by the Southeastern Organ Procurement Foundation. METHODS: Patients of the 13 transplant centers, with cholesterol of 240 mg/dl or greater, who were at least 1 year posttransplant with stable renal function, were randomly assigned to remain on cyclosporine (control) or converted to tacrolimus. Patients converted to tacrolimus were maintained at a level of 5-15 ng/ml, and control patients remained at their previous levels of cyclosporine. Concurrent immunosuppressants were not changed. Levels of total cholesterol, triglycerides, total high-density lipoprotein, low-density lipoprotein (LDL), very-low-density lipoprotein, and apoproteins A and B were monitored before conversion and at months 1, 3, and 6. Renal function and glucose control were evaluated at the beginning and end of the study (month 6). RESULTS: A total of 65 patients were enrolled; 12 patients failed to complete the study. None were removed as a result of acute rejection or graft failure. Fifty-three patients were available for analysis (27 in the tacrolimus group and 26 controls). Demographics were not different between groups. In patients converted to tacrolimus treatment, there was a -55 mg/dl (-16%) (P=0.0031) change in cholesterol, a -48 mg/dl (-25%) (P=0.0014) change in LDL cholesterol, and a -36 mg/dl (-23%) (P=0.034) change in apolipoprotein B. There was no change in renal function, glycemic control, or incidence of new onset diabetes mellitus in the tacrolimus group. CONCLUSION: Conversion from cyclosporine to tacrolimus can be safely done after successful transplantation. Introduction of tacrolimus to a stable renal patient does not effect renal function or glycemic control. Tacrolimus can lower cholesterol, LDL, and apolipoprotein B. Conversion to tacrolimus from cyclosporine should be considered in the treatment of posttransplant hyperlipidemia.

Appearance of the hymen in prepubertal girls.

The recent increase in requests for genital examinations in girls who may have been sexually abused has necessitated detailed information not previously available on normal anatomy of the prepubertal girl. This study was undertaken to document the genital anatomy of 211 girls between the ages of 1 month and 7 years who presented for well child care or nongynecologic complaints and who had no history of sexual abuse. Each child's genitalia was examined and photographed, with findings reported reflecting those observed photographically. The study population consisted of 36% blacks, 33.6% white non-Hispanics, 29.9% Hispanics, and 0.5% Asians. Subjects had a mean age of 21 +/- 20.6 (SD) months. Extensive labial agglutination sufficient to obscure the hymen was noted in 5% (10/211) and partial agglutination in an additional 17% (35/211). A significant difference was noted in hymenal configuration by age, with a fimbriated hymen the most common type (46%) in infants aged 12 months or younger and a crescentic hymen the most common (51%) in girls older than 24 months (P less than or equal to .001). No significant difference was noted in hymen configuration by race. Hymenal bumps (mounds) were observed in 7%, hymenal tags in 3%, vestibular bands in 98%, longitudinal intravaginal ridges in 25%, and external ridges in 15% of subjects in whom the anatomy under study could be visualized. Hymenal notches (clefts) occurred superiorly and laterally on the hymenal rim but none were found inferiorly on the lower half of the hymen. A narrow rounded hymenal ring with a transection was observed in only 1 (0.5%) of 201 subjects and was not considered a normal finding.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitrogen isotopic analyses by isotope-ratio-monitoring gas chromatography / mass spectrometry.

Amino acids containing natural-abundance levels of (15)N were derivatized and analyzed isotopically using a technique in which individual compounds are separated by gas chromatography, combusted on-line, and the product stream sent directly to an isotope-ratio mass spectrometer. For samples of N2 gas, standard deviations of ratio measurement were better than 0.1‰ (Units for δ are parts per thousand or per million (‰).) for samples larger than 400 pmol and better than 0.5‰ for samples larger than 25 pmol (0.1‰ (15)N is equivalent to 0.00004 atom % (15)N). Results duplicated those of conventional, batchwise analyses to within 0.05‰. For combustion of organic compounds yielding CO2/N2 ratios between 14 and 28, in particular for N-acetyl n-propyl derivatives of amino acids, δ values were within 0.25‰ of results obtained using conventional techniques and standard deviations were better than 0.35‰. Pooled data for measurements of all amino acids produced an accuracy and precision of 0.04 and 0.23‰, respectively, when 2 mnol of each amino acid was injected on column and 20% of the stream of combustion products was delivered to the mass spectrometer.

Nitrogen isotopic analyses by isotope-ratio-monitoring gas chromatography/mass spectrometry.

Amino acids containing natural-abundance levels of 15N were derivatized and analyzed isotopically using a technique in which individual compounds are separated by gas chromatography, combusted on-line, and the product stream sent directly to an isotope-ratio mass spectrometer. For samples of N2 gas, standard deviations of ratio measurement were better than 0.1% (Units for delta are parts per thousand or per million (%).) for samples larger than 400 pmol and better than 0.5% for samples larger than 25 pmol (0.1% 15N is equivalent to 0.00004 atom % 15N). Results duplicated those of conventional, batchwise analyses to within 0.05%. For combustion of organic compounds yielding CO2/N2 ratios between 14 and 28, in particular for N-acetyl n-propyl derivatives of amino acids, delta values were within 0.25% of results obtained using conventional techniques and standard deviations were better than 0.35%. Pooled data for measurements of all amino acids produced an accuracy and precision of 0.04 and 0.23%, respectively, when 2 nmol of each amino acid was injected on column and 20% of the stream of combustion products was delivered to the mass spectrometer.