The effects of goal setting and self-instruction on learning a reading comprehension strategy: a study of students with learning disabilities

This study examined the contributions of instruction in goal setting and self-instruction, separately and combined, on the acquisition, maintenance, and generalization of a reading comprehension strategy by fourth-through sixth-grade students with learning disabilities. A previously validated strategy involving the use of story structure to analyze and remember story content was taught to 47 students with learning disabilities using the self-regulated strategy development (SRSD) model. Comparisons were made among students with learning disabilities in four conditions (strategy instruction, strategy instruction plus goal setting, strategy instruction plus self-instruction, and strategy instruction plus goal setting and self-instruction). Result indicated that instruction in the reading strategy produced meaningful, lasting, and generalizable effects on students' story comprehension skills. Furthermore, the comprehension performance of the students with learning disabilities after strategy instruction was indistinguishable from that of a social comparison group of normally achieving students. Explicit instruction in goal setting and self-instruction, however, did not augment the comprehension performance of students with learning disabilities.

Complications of anterior spinal surgery in children

The purpose of this study was to document the medical and surgical complications of anterior spine surgery in children and to identify risk factors for complications. A retrospective chart review was conducted of 599 anterior procedures (24 anterior only, 300 staged anterior/posterior, 175 combined anterior/posterior procedures) performed between 1967 and 1991. Major complications occurred in 7.5% of procedures and minor complications in 33%. Risk factors for major complications were age > 14 years, male gender, kyphotic curve type, curve sizes > 100 degrees, vital capacity < 40% of predicted, and use of thoracotomy. Risk factors for minor complications were age > 14 years, curves > 100 degrees, vital capacity < 40% of predicted, and use of a staged procedure. Multivariate analyses of risk factors identified age > 14 years and curves > 100 degrees as the most significant risk factors for major complications and age > 14 years for minor complications. We concluded that anterior spinal surgery can be performed in children with an acceptable level of risk and that referral for surgery before 14 years of age and before the curve size progresses will significantly reduce the risk of complications.

Commitment to the underserved: evaluating the effect of an extracurricular medical student program on career choice

BACKGROUND

This study was conducted to compare the practice locations and characteristics of physicians who participated as medical students in an extracurricular program to foster interest in careers of service to medically underserved populations with those of their classmates who did not participate in the program.

METHODS

Using a mailed questionnaire, we conducted a cross-sectional study of graduates from the classes of 1983-1987 at one southwestern, public medical school. All Commitment to Underserved People (CUP) participants (n = 94) and a random sample of nonparticipating classmates (n = 188) were surveyed. CUP is an extracurricular project with components in each of 4 years of medical school that provides peer and faculty support, curriculum enrichment, and direct service to medically underserved populations. Outcome measures included the size of community of practice, practice type, and practice patient characteristics.

RESULTS

Sixty seven (71%) of CUP participants and 126 (67%) of nonparticipants responded. CUP participants were more likely to be women, to specialize in family practice, to practice in the Indian Health Service (IHS) or overseas, to be located in a community of 25,000 or less, and to have participated in the state, service-payback loan program. In multiple regression, the specialty of family practice was associated with practice in a small community, the IHS, and a community health center; CUP participation was correlated with practice in small communities, the IHS, and a foreign country.

CONCLUSIONS

Participation in the CUP program was associated with the specialty choice of family practice and with practice in settings associated with medically underserved populations. The CUP program has been successful in sustaining entering medical students' interests in underserved practice.

Effects of developmental exposure to indole-3-carbinol or 2,3,7,8-tetrachlorodibenzo-p-dioxin on reproductive potential of male rat offspring

Treatment of pregnant female Sprague-Dawley rats on Gestational Day 15 with a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (0.5, 1.0, or 2.0 micrograms/kg) or indole-3-carbinol (I3C, 1.0 or 100 mg/kg), an aryl hydrocarbon (Ah) receptor agonist which is found in cruciferous vegetables, resulted in reproductive abnormalities in the male offspring (three to five litters in each treatment group). Anogenital distance and crown to rump length were altered by both compounds; however, the timing of the effects (Day 1 or 5) was variable and the responses were not necessarily dose-dependent. In 62-day-old offspring, seminal vesicle (24 to 26%), prostate (32 to 44%), testicular parenchymal (14%), and epididymal weight (19%) were decreased by one or more doses of TCDD. In contrast, I3C at one or more doses decreased daily sperm production/g testicular parenchyma (13 to 20%) and daily sperm production/testis (22%). Total number of sperum in the epididymis was significantly decreased (30 to 33%) in rats perinatally exposed to TCDD and this was due to a decreased (49 to 51%) number of sperm in the tail of the epididymis. Perinatal exposure to I3C did not affect any of these parameters. TCDD did not affect epididymal transit time of sperm through the complete epididymis at any of the doses (0.5 to 2.0 micrograms/kg). However, at the two highest doses (1.0 and 2.0 micrograms/kg), TCDD increased epididymal transit rate of sperm through the tail of the epididymis by 33 and 37%, respectively. In contrast, primarily due to decreased transit rate (39%) of sperm through the head plus body of the epididymis. I3C (1 mg/kg) significantly increased total epididymal transit time by 31%. In conclusion, perinatal exposure of pregnant rats to I3C, an Ah receptor agonist similar to TCDD, causes reproductive abnormalities in male rat offspring; however, I3C and TCDD elicited both common and different responses.

Five year trends in cardiac catheterization: a report from the Registry of the Society for Cardiac Angiography and Interventions

The Society for Cardiac Angiography and Interventions has maintained a registry of cardiac catheterizations since 1979 and of percutaneous cardiac interventions since 1990. Data from 392,923 procedures (317,592 diagnostic catheterizations, 74,963 coronary interventions, and 368 valvuloplasties) for the years 1990-1994 inclusive are presented. Over the 5 year period there was a trend toward same day and 23 hr discharges (19% in 1990 to 29% in 1994), and a decrease in combined right and left heart procedures from 38% to 26%. For cardiac catheterizations ionic contrast use declined from 26% of procedures to 13% in 1994. The use of ionic contrast was even lower in interventional procedures, with laboratories reporting use in 21% of procedures in 1990 dropping to 9% in 1994. Balloons were the first choice device in 92.5% of native arteries and 82.7% of grafts in 1994. For the first time in 1994 more mitral than aortic valvuloplasties were reported.

Increased expression of xanthine oxidase and insulin-like growth factor I (IGF-I) immunoreactivity in skeletal muscle after strenuous exercise in humans

The present study investigated the effect of 7 days of strenuous exercise on the quantity of xanthine oxidase and IGF-I in muscle. Fifteen male military trainees performed 1 week of terrain marching and warfare exercises. Muscle biopsies and blood samples were obtained prior to and after the week. After the week, the number of xanthine oxidase immunoreactive cells, identified as capillary endothelial cells and leucocytes, and the number of IGF-I immunoreactive cells, mainly vascular cells but also cells tentatively identified as satellite cells, were higher in the muscle (P < 0.05). Plasma creatine kinase activity was 650% higher after the week (P < 0.001) and the muscle content of hydroxyproline was elevated by 160% 2 months post-exercise (P < 0.05), both findings implying injury to the muscle. The present data provide a first observation of an elevated level of xanthine oxidase and IGF-I in human skeletal muscle after exercise. It is proposed that both substances increased as a result of cellular damage: xanthine oxidase because of the influence of immunomodulators, and IGF-I in association with regenerative processes. The increased expression of IGF-I in the muscle could, however, also reflect cellular growth in response to an elevated load on the muscle and the vascular bed.

Pain responses of hospitalized infants and children to venipuncture and intravenous cannulation

The purpose of this study was to describe the experience of pain in infants and children in response to venipuncture and intravenous cannulation. Data on physiological, behavioral, and subjective responses were collected from 90 infants and children, in subgroups of 1 to 12 months, 1 to 3 years, 4 to 6 years, and 7 to 12 years. Changes in behavior were significant in all four groups, although the toddler group was the only group that showed a significant physiological change. The subjective measures showed that the children were able to identify their pain sites and intensity.

Disparities in clinical laboratory performance for blood lead analysis

OBJECTIVE

To evaluate the validity of blood lead analysis for clinical specimens.

DESIGN

We submitted blood lead samples with a known lead concentration, in a blinded fashion, as clinical specimens to 18 laboratories. These laboratories were surveyed for the following characteristics that were hypothesized to be related to assay validity: laboratory ownership (state vs private), participation in the Centers for Disease Control Blood Lead Proficiency Program, assay method, and price. Each laboratory received 6 specimens with an actual blood lead (ABPb) concentration of 0.43 mumol/L (9 micrograms/dL) and 3 additional specimens--each with an ABPb concentration of 0.33, 0.89, and 1.59 mumol/L (6.9, 18.4, and 32.9 micrograms/dL, respectively).

OUTCOME MEASURES

Misclassification error rates for reporting an elevation ( > or = 0.48 mumol/L [ > or = 10 micrograms/dL) in the blood lead concentration, the within-laboratory mean and coefficient of variation (CV) (for multiple specimens with an ABPb concentration of 0.43 mumol/L [9 micrograms/dL]), and the adjusted odds of a reported blood lead concentration differing from those of an ABPb concentration by more than 0.14 mumol/L (3 micrograms/dL).

RESULTS

Blood lead results were obtained for 157 of 162 submissions. One laboratory reported all blood lead specimens as "below 0.48 mumol/L (10 micrograms/dL)." Two (11%) of 18 specimens with an ABPb concentration of 0.89 mumol/L (18.4 micrograms/dL) and 1 (6%) of 17 with an ABPb concentration of 1.59 mumol/L (32.9 micrograms/dL) were classified as below 0.48 mumol/L (10 micrograms/dL); 2 (11%) of 18 with an ABPb concentration of 0.33 mumol/L (6.9 micrograms/dL) and 44 (42%) of 104 with an ABPb concentration of 0.43 mumol/L (9 micrograms/dL) were classified as 0.48 mumol/L or greater ( > or = 10 micrograms/dL). For specimens with an ABPb concentration of 0.43 mumol/L (9 micrograms/dL), the within-laboratory mean ranged from 0.23 to 0.52 mumol/L (4.8-10.7 micrograms/dL); the CV ranged from 3% to 37%. Laboratories that used anodic stripping voltammetry were 6.3 (95% confidence interval, 1.4-28.6) times more likely to report a specimen that differed from the ABPb concentration by more than 0.14 mumol/L (3 micrograms/dL) than those that used atomic absorption methods. No other laboratory characteristic predicted discordance between the reported blood lead and ABPb concentrations.

CONCLUSIONS

This study documents wide variation in the validity of the blood lead measurement among clinical laboratories. While the performance of some laboratories far exceeded the criteria of the Centers for Disease Control Blood Lead Proficiency Program, others made large errors that could have resulted in the false-negative misclassification of children with significant lead exposure. Given these differences, the purchasers of laboratory services may require access to laboratory proficiency data to make rational choices among clinical laboratories. Further study of laboratory performance on clinical specimens is required to determine if order-of-magnitude errors occur with sufficient frequency to warrant routine submission of blinded quality control specimens by proficiency programs and to determine the cause of the poor performance of laboratories that used the anodic stripping voltammetry methodology.

A phase II study of cyclophosphamide followed by PIXY321 as a means of mobilizing peripheral blood hematopoietic progenitor cells

Fourteen patients with stage II-IV breast cancer were enrolled in a phase II study of cyclophosphamide followed by PIXY321 as a means of mobilizing peripheral blood progenitor cells (PBPC). All 14 women tolerated PIXY321 well, with the predominant toxicities being erythema at the injection site, fever, and arthralgias. A median of two aphereses yielded a mean of 1.3 x 10(8) mononuclear cells/kg, 8.9 x 10(4) colony-forming units-granulocyte/macrophage (CFU-GM)/kg, and 4.5 x 10(6) CD34+ cells/kg. All 14 patients underwent high-dose chemotherapy with PBPC support, the median day to ANC >500 cells/microliter was 10.6, and the median day to platelets >20,000 cells/microliter was 13. The day of 90th percentile platelet recovery was 15. When compared to PBPCs mobilized by cyclophosphamide followed by GM-CSF, the use of PIXY321 may confer an advantage of enhanced platelet recovery.

Effect of developmental age or time after transplantation on Sertoli cell number and testicular size in inbred Fischer rats

The objectives were to establish the developmental age of Fischer rats at which the Sertoli cell number is stabilized, to establish the normal reference plateau number of Sertoli cells for evaluation of testes after transplantation, and to determine whether the developmental pattern establishing Sertoli cell proliferation and stability are similar between intact and transplanted testes. Sertoli cell number was determined at ages 1--120 days in intact rats and at various times (10-90 days) after transplantation of prenatal or neonatal tests. Tests were fixed by vascular perfusion or by immersion with 2% glutaraldehyde and and immersion in 1% osmium and were embedded in Epon 812. Sections and serial sections were cut at 0.5 micrometer to determine the Sertoli cell nuclei volume density and the volume of an individual Sertoli cell nucleus by brightfield microscopy or at 20 micrometers to determine the maximum height and width of nuclei. A correction factor was calculated for intact (0.663 +/- 0.025) or for transplanted (0.558 +/- 0.029) testes to determine the volume of a single Sertoli cell nucleus from height and width measurements. In intact testes, Sertoli cell numbers significantly increased to Day 20 but were not different between 15 and 90 days. Sertoli cell number in prenatal or neonatal transplanted testes increased to 20 or 30 days posttransplantation and then stabilized to Day 60 or 90. There was no difference in the plateau number of Sertoli cells per rat between prenatal and neonatal testes. Sertoli cells in 10-day- and 30-day-transplanted testes incorporated 3H-thymidine when placed in culture. A few tubules had complete spermatogenesis at 90 days posttransplantation, indicating that Sertoli cells in some of these tubules were functional. Leydig cell structure appeared to be normal. Leukocytic infiltration of testes was not observed in intact rats or in rats receiving neonatal testes. Although transplanted testes showed a delay in reaching the plateau value for Sertoli cell number per testis and although the value reached was lower, the developmental pattern of Sertoli cell proliferation in transplanted testes was similar to that in intact rats.

Testicular composition, number of A spermatogonia, germ cell ratios, and number of spermatids in three different breeds of boars

Seminal quality, including the number of spermatozoa in the ejaculate, varies among breeds of boars. Variation in seminal quality may be explained by breed differences in testicular size and composition. The objective of this study was to characterize testicular composition and population sizes of germ cells and somatic cells in three different breeds of boars. Testes from mature and normal Meishan (M, n = 5; age 225 days), Whitecross (WC, n = 5; age 346 days), and West African (WA, n = 5; age 322 days) boars were either fixed in Zenker-formol or perfused with glutaraldehyde, embedded in Epon, sectioned at 0.5 microns or 20 microns and evaluated stereologically for germ cells, Leydig cells, Sertoli cells, and other testicular structures. The paired parenchymal weight was higher (P < 0.05) in the WC (498 +/- 35 g) than in the M (247 +/- 17 g) or WA (133 +/- 10 g). The nuclear volumes per boar of Sertoli cells, type A spermatogonia, leptotene, zygotene, pachytene, secondary spermatocytes, spermatids with spherical nuclei, and spermatids with elongated nuclei were higher (P < 0.05) in the WC than in the M or WA. The nuclear volumes per boar of blood vessels and Leydig cells were exceptionally higher (P < 0.05) in the M than in the WC or WA. The average germ cell nuclear diameters were similar (P > 0.05) for the M and WC but least (P < 0.05) in the WA breed. Also, the nuclear diameters of Leydig cells and Sertoli cells were higher (P < 0.05) in the M than in the WC or WA. The population sizes of all the intratubular components were positively correlated (P < 0.05) with testicular size (weight). Volume density of seminiferous tubules was similar in the WA and WC, but was lowest in the M, who had the highest density of Leydig cells. However, due to the larger testes, all germ cell types and Sertoli cells were higher in the WC than in the WA or M. The M and WA had similar low numbers of type A spermatogonia, but there was less term cell degeneration in M than in Wa, such that M spermatids were intermediate in number between WA and WC.

Number and function of Sertoli cells, number and yield of spermatogonia, and daily sperm production in three breeds of boar

The objective of this study was to determine the number of Sertoli cells per boar, daily sperm production, and germ cell yield per type A spermatogonium in mature Whitecross, Meishan, and West African boars. The paired parenchymal mass was greatest in the Whitecross boars and greater in Meishan than in West African boars. Daily sperm production per boar (x 10(9)) differed significantly (P < 0.05) among breeds (Whitecross: 12.5 +/- 1.5; Meishan: 6.0 +/- 0.5; West African: 2.9 +/- 0.3). Daily sperm production per boar was positively (P < 0.01) correlated with parenchymal mass (r = 0.97), number of A spermatogonia per testis (r = 0.88), and Sertoli cells per testis (r = 0.87). Daily sperm production per gram of testis was similar among breeds. Number of Sertoli cells and number of type A spermatogonia per boar were greater for the Whitecross but similar in the Meishan and West African boars. The number of Stage VII germ cells per Sertoli cell was greater (P < 0.05) in the Meishan (39.08 +/- 5.07), but similar in the Whitecross (19.91 +/- 1.62) and West African boars (15.81 +/- 2.43). The number of type A spermatogonia per testis was highly and positively (P < 0.01) correlated with number of Sertoli cells per testis (r = 0.95), and parenchymal mass (r = 0.88). There was a trend for the spermatid yield per type A spermatogonium to be greater in the Meishan boars, and this ratio was positively correlated with spermatid:Sertoli cell ratio (r = 0.62) but not with daily sperm production per boar or Sertoli cells per testis. No significant germ cell degeneration occurred during the long meiotic prophase, but the loss of progeny during postprophase of meiosis averaged 32.62% across all breeds. Germ cell degeneration was similar (P > 0.05) across breeds during spermiogenesis, and on average amounted to 8.6%. The increased number of type A spermatogonia and of Sertoli cells associated with larger testes for the Whitecross over West African or Meishan boars is sufficient to explain the higher sperm production in the Whitecross. However, the lower index of degeneration and more efficient Sertoli cell function in Meishan boars results in the daily sperm production being intermediate between that of the Whitecross and West African boars.

Effect of hypophysectomy, sex of host, and/or number of transplanted testes on Sertoli cell number and testicular size of syngeneic testicular grafts in Fischer rats

One or more neonatal testicular grafts were transplanted for 60-65 days into young adult inbred Fischer rats to determine the effect of hypophysectomy, sex of host, and/or the number of transplanted testes on testicular size and Sertoli cell number. All host rats had been castrated or ovariectomized and some were hypophysectomized as well. At the end of the treatment, testes were fixed and embedded in Epon before histologic sections (0.5 micrometer or 20 micrometers) were evaluated by stereology. Testicular grafts placed in castrated adult male rats with intact pituitaries weighed more (p < 0.01) and had more (p < 0.01) Sertoli cells than those placed in hypophysectomized hosts. Testicular grafts that were recovered from hypophysectomized rats 34 days posttransplantation and placed in pituitary-intact males for 30 day had larger (p < 0.05) parenchymal weights and more Sertoli cells than did testes re-transplanted into hypophysectomized rats. However, this delayed period of Sertoli cell proliferation id not extend to 65 days of hypophysectomy. When two or four testes were transplanted into castrated males or ovariectomized female hosts for 65 days, there was no difference in the graft weights or Sertoli cell numbers between sexes. Four transplanted testes per rat produced more (p < 0.01) total testicular parenchyma and a greater (p < 0.01) number of Sertoli cells per testis than did two tests regardless of sex of the host. This model has shown that the period of Sertoli cell proliferation can be delayed by hypophysectomy, that Sertoli cell number can be influenced by endogenous hormones, and that a major component in regulation of testicular size is at the level of the testis in this model. Hence, this model should facilitate study of experimental endocrine manipulation control and potential experimental intervention to increase Sertoli cell number and testicular size.

Partial wave in human seminiferous tubules appears to be a random occurrence

Serial cross sections were evaluated to determine the architectural arrangement of stages among men with varied spermatogenic efficiencies. Using autopsy specimens, glutaraldehyde-perfused testes from men with low or high daily sperm production per g parenchyma were compared. Lobes of testicular parenchyma were teased from connective tissue septa, further fixed in osmium, and embedded such that the straight portions of tubules could be sectioned perpendicularly. Unstained 22 microns serial sections were sectioned optically with Nomarski optics. Paired photomicrographs of each tubular cross section were taken under a 40 x objective, and stages of the spermatogenic cycle were mapped by two observers using Clermont's criteria (Clermont, 1963). For comparison, numbers (1-6) were assigned randomly to the stages, the stages were plotted in two dimensions (length and circumference of tubule) as if the tubule were cut down its length and laid flat, and geometric centers were plotted for each stage. Geometric centers consecutive and/or non-consecutive stages appeared to form an angle down the length of the tubule. When considering helical patterns along the tubule, men with neither low nor high spermatogenic efficiency had a complete wave composed of all six consecutive stages. The helical pattern of geometric centers indicated only 2-4 consecutive stages when the actual values of stages were used or when random numbers were substituted for actual numerical value of stages. The number of consecutive stages in tubules from these men was not different from consecutiveness found when stages were assigned random numbers. Given that no complete wave was found, regardless of spermatogenic efficiency, and that the degree of consecutiveness of stages down a helical pattern in human seminiferous tubules could be generated from random numbers, the arrangement of stages in human seminiferous tubules may simply be a random occurrence.

Isolated pancreas rejection in combined kidney pancreas tranplantation

The clinical success of pancreas transplantation is limited by the difficulty in diagnosing rejection. In simultaneous pancreas kidney (SPK) transplantation, the diagnosis of pancreatic rejection is particularly difficult in the absence of clinical evidence of kidney rejection. Moreover, patients receiving only pancreas grafts will not have a concomitantly grafted kidney to serve as a "sentinel" for rejection. Percutaneous pancreas graft biopsy has been reported in a few small series but has not been adopted for broad clinical use. We describe the evaluation of 69 consecutive episodes of suspected isolated pancreas allograft rejection by percutaneous pancreas allograft biopsy. These rejection episodes occurred in 41 patients with bladder-drained pancreas transplants (25 SPK, 14 pancrease after kidney transplants [PAK], amd two pancreas transplant alone [PTA]). The indications for percutaneous pancreas biopsy were a twofold or greater increase in serum amylase or lipase, or a sustained 40% to 50% drop in urine amylase in the setting of no evidence of renal allograft dysfunction in SPK transplants. Biopsies were performed with color-flow Doppler ultrasound localization using an 18-gauge automated biopsy needle. Pancreatic tissue adequate for histologic evaluation was obtained in 61 of 69 cases (88%). There were two cases of intraabdominal bleeding, one of which required surgical intervention; the other resolved spontaneously. Histologic assessment of the biopsies demonstrated varying degrees of acute cellular rejection in 48 of 61 specimens (79%). Twelve specimens (20%) were free of histologic evidence of rejection, and one specimen (2%) showed acute pancreatitis. At the time of suspected rejection mean serum amylase and lipase values were increased 3.6 and 8.3-fold, respectively, and urine amylase was decreased by a mean of 45%. We conclude that the commonly used markers for pancreas allograft rejection are only about 80% specific for acute rejection. Percutaneous pancreas allograft biopsy is safe and allows the avoidance of unnecessary antirejection therapy with its attendant side effects and cost.

Body fat distribution and non-insulin-dependent diabetes: comparison of a fiber-rich, high-carbohydrate, low-fat (23%) diet and a 35% fat diet high in monounsaturated fat

The effects of a fiber-rich, high-carbohydrate, low-fat (HCLF) diet and a modified-fat (MF) diet high in monounsaturated fat on body fat distribution were examined by dual-energy X-ray absorptiometry (DXA) in 16 subjects with non-insulin-dependent diabetes (NIDDM) during a randomized crossover study. Subjects lost similar amounts of body fat consuming the HCLF and MF diets (-0.83 +/- 0.37 and -0.87 +/- 0.40 kg, respectively) despite a marked difference in total fat consumption. With the MF diet, the ratio of upper- to lower-body fat (UF:LF) remained unchanged because fat was lost proportionately from the upper and lower body. In contrast, with the HCLF diet, a disproportionate loss of lower-body fat caused the UF:LF to increase. The effects of diet on regional body fat loss were significant (P < 0.05, two-factor repeated-measures ANOVA).

Tandem high-dose chemotherapy supported by hematopoietic progenitor cells yields prolonged survival in stage IV breast cancer

The aim of this phase II study was to determine the feasibility of using two (tandem) courses of high-dose alkylating agents with bone marrow or peripheral blood progenitor cell support in women with stage IV breast cancer. Women with stage IV breast cancer who had achieved a CR or PR during conventional chemotherapy were enrolled in a phase II trial of high-dose cyclophosphamide 7500 mg/m2 and thiotepa 675 mg/m2 (C+T) followed within 180 days by high-dose melphalan (M) 140 mg/m2. Bone marrow and/or GM-CSF mobilized peripheral blood hematopoietic progenitor cells were used to support high-dose C+T and high-dose M. Twenty-seven women were enrolled in this trial. The median age was 45 years (range 32-56). The median PS was 0 and all patients had achieved either a CR (4/27, 15%) or PR (23/27, 85%) to conventional chemotherapy. All 27 women underwent high dose C+T. The predominant toxicities were mucositis (81%), and diarrhea (81%); two patients (7%) died from infectious complications. Following C+T, the median time to hematologic recovery for neutrophils (ANC > 500 cells/mu 1) was 12 days and for platelets (>20 000 cell/mu 1), 23 days. Following C+T, 18 of 22 patients received high dose M; the predominant toxicities were nausea, vomiting (70%), and mucositis (91%). The median time to hematologic recovery for the ANC was 13 days and for platelets, 18 days. The overall response after high dose C+T and high dose M was 67% (CR, 15/27 patients (56%) and PR* (complete resolution of all measurable disease but persistent lytic disease or positive bone scan) 3/27 patients (11%). With median follow-up of 24 months, the actuarial freedom from relapse or treatment failure is 56% at 24 months. At 30 months 56% of patients are alive. For patients who achieve a CR or PR* the actuarial freedom from relapse or treatment failure at 24 months is 88%. In women with stage IV breast cancer who attain a CR or PR to conventional chemotherapy, tandem high-dose chemotherapy with ABMT can lead to prolonged relapse-free survival.

MAG3 renal transplant tomography SPECT with a non-SPECT agent

The authors encountered a renal transplant patient in whom tubular stasis permitted sufficient time to perform SPECT using Tc-99m MAG3. SPECT revealed a defect that was not apparent on the planar study. Renal biopsy showed acute vascular rejection. On a subsequent Tc-99m MAG3 SPECT study the defect had resolved.

In vivo MRI visualization of acute myocardial ischemia and reperfusion in ferrets by the persistent action of the contrast agent Gd (BME-DTTA)

BACKGROUND

Contrast agent-enhanced magnetic resonance imaging (MRI) has the potential to visualize myocardial ischemia. To date, however, no agent has been found that has a sustained effect that allows MRI detection for the entire duration of ischemia and reperfusion and thus is useful in conjunction with stress test MRI. In this article, we introduce the gadolinium complex of N3,N6-bis(2'-myrisotyloxyethyl)-1,8-dioxo-triethylene- tetraamine-N,N,N1,N1-tetraacetic acid [Gd(BME-DTTA)], an agent potentially useful for such a purpose.

METHODS AND RESULTS

Four protocols were carried out. ECG-triggered, partially T1-weighted, spin-echo MRI was used in protocols A through C. In protocol A, in nonischemic ferrets, 50 mumol/kg Gd(BME-DTTA) induced a 70 +/- 5% intensity enhancement lasting 3 hours. In protocol B, the left anterior descending coronary artery was occluded, and a 99mTc-sestamibi-induced autoradiographic contrast verified (r = .87, P < .01) a Gd(BME-DTTA)-induced (n = 5) or Gd(DTPA)-induced (n = 4) MRI contrast. In the Gd(BME-DTTA) group a sustained contrast and in the Gd(DTPA) group a short-lived contrast were observed. In protocol C (n = 11), during ischemia, a 31 +/- 3.3% (P < .02) contrast was evident between the ischemic and nonischemic myocardial regions. Upon reperfusion, a contrast of 19 +/- 3% (P < .05) and 13 +/- 4.5% (P < .05) persisted for 5 and 15 minutes, respectively. Beyond 15 minutes, the contrast continued to diminish gradually. Nonradioactive microspheres verified (r = .87, P < .05) ischemia and reperfusion in this model. In protocol D (n = 4), blood delta R1 data showed that the blood pool retained Gd(BME-DTTA) for the entire time frame of the experiment at high enough concentration to provide an appropriate wash-in effect during the initial contrast enhancement and during reperfusion.

CONCLUSIONS

This study demonstrates that Gd(BME-DTTA) induces a sustained MRI contrast between regions of normal versus ischemic myocardium, showing the potential of this agent for the diagnosis of ischemic heart disease in conjunction with stress tests.

Efficiency of spermatogenesis

Spermatogenesis is a process of division and differentiation by which spermatozoa are produced in seminiferous tubules. A measure of efficiency of spermatogenesis is the estimated number of spermatozoa produced per day per gram of testicular parenchyma. This measure is not influenced by species differences in testicular size; however, it is influenced by species differences in the numerical density of germ cells and in the life spans of these cells. Seminiferous tubules are composed of somatic cells (myoid cells and Sertoli cells), and germ cells (spermatogonia, spermatocytes, and spermatids). Activity of these three germ cells divide spermatogenesis into spermatocytogenesis, meiosis, and spermiogenesis, respectively. Spermatocytegenesis involves mitotic cell division to increase the yield of spermatogenesis and to produce stem cells and primary spermatocytes. Meiosis involves duplication and exchange of genetic material and two cell divisions that reduce the chromosome number and yield four spermatids. Spermiogenesis is the differentiation of spherical spermatids into mature spermatids which are released at the luminal free surface as spermatozoa. The spermatogenic cycle is superimposed on the three major divisions of spermatogenesis. Spermatogenesis and germ cell degeneration can be quantified from numbers of germ cells in various steps of development throughout spermatogenesis, and quantitative measures are related to number of spermatozoa in the ejaculate. Germ cell degeneration occurs throughout spermatogenesis; however, the greatest impact occurs during spermatocytogenesis and meiosis. Efficiency of spermatogenesis is related to the amount of germ cell degeneration, pubertal development, season of the year, and aging of humans and animals. Number of Sertoli cells and amount of smooth endoplasmic reticulum of Leydig cells (but not Leydig cell number) are related to efficiency of spermatogenesis. In humans, efficiency of spermatogenesis is reflected in number of spermatogenic stages per cross-section and number of missing generations within each stage; however, the arrangement of stages along the tubular length does not reflect differences in the efficiency of spermatogenesis. In short, spermatogenesis involves both mitotic and meiotic cell divisions and an unsurpassed example of cell differentiation in the production of the spermatozoon, and daily sperm production per g parenchyma is a measure of its efficiency.