Neurenteric cyst of the conus medullaris

Background:

Neurenteric cysts (NECs) are rare developmental malformations of the central nervous system (CNS) which originate as benign congenital lesions. They originate from developmental foregut precursors, and are presumed to be the result of abnormal partitioning of the embryonic notochord plate. Such NECs predominantly arise in the cervical region in patients around 6 years of age or in their twenties or thirties. Notably, NECs of the conus medullaris are exceedingly rare, especially in patients of advanced age.

Case Description:

A 70-year-old male presented with bilateral upper thigh and leg pain of over 20 years duration. His pain worsened over the past 3 years, and he sought surgical management. Although his neurological exam was normal, the lumbar magnetic resonance imaging revealed an intradural, nonenhancing, thin-walled, cystic lesion at L1/conus medullaris. The lesion was successfully resected without any adverse sequelae.

Conclusions:

NECs are rare congenital legions that involve the spine. Here, an L1 intradural extramedullay neuroenteric cyst of the conus medullaris was resected without complications.

STUDIES ON NUCLEAR STRUCTURE AND FUNCTION IN TETRAHYMENA PYRIFORMIS: I. RNA Synthesis in Macro- and Micronuclei

Tetrahymena in the log phase of growth were pulse labeled with uridine-(3)H, fixed in acetic-alcohol, extracted with DNase, and embedded in Epon. 0.5-micro sections were cut, coated with Kodak NTB-2 emulsion, and developed after suitable exposures. Grains were counted above macronuclei, above 1000 micronuclei, and above 1000 micronucleus-sized "blanks" which were situated next to micronuclei in the visual field by means of a camera lucida. An analysis of grain counts showed that micronuclei were less than (1/2)(000) as active as macronuclei on the basis of grains per nucleus. Since micronuclei contained, on the average, about (1/2)(0) as much DNA as macronuclei, micronuclear DNA had less than 1% of the specific activity of macronuclear DNA in RNA synthesis. However, even this small amount of apparent incorporation was not significantly different from zero. Comparisons of the frequency distributions of labeled micronuclei with those of micronuclear "blanks" showed no evidence of a small population of labeled nuclei such as might be expected if micronuclei synthesized RNA for only a brief portion of the cell cycle. We conclude from these studies that there is no detectable RNA synthesis in Tetrahymena micronuclei during vegetative growth and reproduction.

Differences in radiographic features of knee osteoarthritis in African-Americans and Caucasians: the Johnston county osteoarthritis project

OBJECTIVE

To examine racial differences in tibiofemoral joint (TFJ) and patellofemoral joint (PFJ) radiographic osteoarthritis in African-American (AA) and Caucasian men and women.

METHOD

Multiple logistic regression was used to evaluate cross-sectional associations between race and tibiofemoral osteoarthritis (TF-OA) and the presence, severity and location of individual radiographic features of tibiofemoral joint osteoarthritis [TFJ-OA] (osteophytes, joint space narrowing [JSN], sclerosis and cysts) and patellofemoral joint osteoarthritis (PFJ-OA) (osteophytes, JSN and sclerosis), using data from the Johnston County Osteoarthritis Project. Proportional odds ratios (POR) assessed severity of TF-OA, TFJ and PFJ osteophytes, and JSN, adjusting for confounders. Generalized estimating equations accounted for auto-correlation of knees.

RESULTS

Among 3187 participants (32.5% AAs; 62% women; mean age 62 years), 6300 TFJ and 1957 PFJ were included. Compared to Caucasians, AA men were more likely to have TF-OA (adjusted odds ratio [aOR]=1.36; 95% CI, 1.00-1.86); tri-compartmental TFJ and PFJ osteophytes (aOR=3.06; 95%CI=1.96-4.78), and TFJ and PFJ sclerosis. AA women were more likely than Caucasian to have medial TFJ and tri-compartmental osteophytes (aOR=2.13; 1.55-2.94), and lateral TFJ sclerosis. AAs had more severe TF-OA than Caucasians (adjusted cumulative odds ratio [aPOR]=2.08; 95% CI, 1.19-3.64 for men; aPOR=1.56; 95% CI, 1.06-2.29 for women) and were more likely to have lateral TFJ JSN.

CONCLUSIONS

Compared to Caucasians, AAs were more likely to have more severe TF-OA; tri-compartmental disease; and lateral JSN. Further research to clarify the discrepancy between radiographic features in OA among races appears warranted.

Paradoxical effects of viscosity on the VentrAssist rotary blood pump

The ability of the VentrAssist blood pump to perform at its optimum design point is determined by a number of factors such as geometry of the pump, surface roughness, and fluid properties. Once the fluid properties are known, the performance characteristics of the pump can be optimized for that fluid. It is important to understand the effects of dynamic viscosity mu (called simply viscosity hereafter) on the performance characteristics and stability of the pump. The performance envelope of the pump and the needs of the patient must be matched. The VentrAssist pump has no shaft, seals, or fixed bearings and relies on the fluid-dynamic forces to maintain its effective performance. A number of different fluids have been tested to determine the effects of viscosity and density on pump performance. These include aqueous glycerol, red blood cells (RBCs) suspended in phosphate buffered saline solution (PBS), and Haemaccel. The effects of viscosity on the bearing stiffness, stage efficiency, and the pressure-flow rate (HQ) are characterized. The experimental results show a slight increase in the pressure rise across the pump shown as a positive upward shift of the H-Q curves with a decrease in viscosity; however, this is relatively small. A paradox in system efficiency exists: for a given fluid asymptotic viscosity, the system efficiency (product of magnetic and stage efficiency) using Haemaccel or PBS is greater than for the same viscosity of aqueous glycerol.

Strategies for locating disulfide bonds in a monoclonal antibody via mass spectrometry

The location of the disulfide bonds in a recombinant monoclonal antibody was confirmed by matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) and electrospray ionization (ESI) mass spectrometry (MS). A non-reduced Endoproteinase Lys-C (Endo Lys-C) digest of the antibody was analyzed directly by MALDI-TOFMS. The sample was then reduced on-plate by depositing dithiothreitol (DTT) on the sample spot and re-analyzed by MALDI-TOFMS. The disulfide bonds were assigned based on the disappearance of certain mass ions in the non-reduced digest and the appearance of product ions in the reduced digest. A rapid LC/ESI-MS protocol was also developed to determine the location of the disulfide bonds. The peptides generated from the Endo Lys-C digest of the antibody were partially separated on a high performance liquid chromatography (HPLC) column by utilizing a steep gradient and analyzed by ESI-MS. The masses of the partially resolved peptides were determined by deconvoluting the mass spectra.

Epidermal growth factor (EGF) and EGF receptor in hypospadias

OBJECTIVE

To determine whether alterations in epidermal growth factor (EGF), which plays a major role both in the masculinization of the genitourinary tract and in wound healing, or EGF receptor (EGFR) expression are associated with hypospadias.

PATIENTS AND METHODS

The prepuces from 22 children undergoing circumcision (median age 27 months, range 5-87) and skin biopsies from 16 children undergoing surgery for hypospadias (median age 12 months, range 3-57) were studied. Fourteen patients had distal, one had mid-shaft and one had penoscrotal hypospadias. Immunoperoxidase staining was carried out for EGF and EGFR and the density of the staining quantified using image cytometry by an operator unaware of the diagnosis.

RESULTS

The median EGF density in foreskins obtained by circumcision was 75% (mean 73, SE 2.1) compared with 54% (mean 52, SE 3.9) for tissue samples from patients with hypospadias (P < 0.001); the mean EGFR was similar in both materials.

CONCLUSION

The mean EGF value was deficient in skin adjacent to hypospadias defects compared to normal phallic skin, suggesting that the inadequate expression of EGF may be related to the aetiology of hypospadias and to possible wound complications following surgery for hypospadias.

Effects of acute right ventricular ischemia on ventricular interactions during prosthetic left ventricular support

Systolic ventricular interactions may be partially responsible for right ventricular failure that sometimes occurs during clinical use of prosthetic left ventricular assist devices. In this hypothesis, it is proposed that the left ventricular assist device reduces left ventricular pressure and its contribution to right ventricular performance, thus impairing right ventricular output. On the other hand, these effects may be small compared with other causes of right ventricular failure such as ischemia. To test the systolic interaction hypothesis in the normal and ischemic right ventricle, we used a left ventricular assist device to pressure unload the left ventricle of anesthetized pigs, and we compared its effect on right heart function before and after 2 minutes of acute right coronary artery occlusion as a model of right heart failure. Pigs were instrumented for measurements of septal to left ventricular and right ventricular free wall dimensions with ultrasonic crystals, ventricular chamber pressures, and cardiac output with a pulmonary artery blood flow probe. Without right ventricular ischemia, the left ventricular assist device produced an 80% +/- 6% reduction in left ventricular pressure-time integral while maintaining aortic pressure. This resulted in a leftward septal shift with an 11.6% +/- 1.8% decrease in left ventricular septal-to-free wall dimension and a 12.5% +/- 2.4% increase in right ventricular septal-to-free wall dimension, with no changes in right ventricular cardiac output or stroke work. In contrast, right coronary artery occlusion alone produced right heart failure, with a 50% +/- 6% reduction in right ventricular global stroke work and 26% +/- 6% and 27% +/- 3% reductions in cardiac output and right ventricular peak systolic pressure, respectively. This right heart failure persisted during left ventricular unloading with the left ventricular assist device, which resulted in further leftward septal shifting and unchanged but still depressed stroke work and flow output. These findings support the hypothesis that a preexisting pathologic condition is the dominant factor in determining right ventricular function during prosthetic left ventricular support and that direct anatomic interactions play a minor role.

Changes in adaptive behavior of older adults with mental retardation following deinstitutionalization

Changes in adaptive functioning of 32 older adults with mental retardation following deinstitutionalization were assessed. The Adaptive Behavior Scale was administered at two times (separated by 1.5 years) for these adults, who were transferred from a state-operated institution to an ICF-MR facility. An overall increase in both adaptive and maladaptive behavior was found. In addition, female residents and those with moderate/mild levels of retardation had higher levels of adaptive functioning than did males and those with severe levels of retardation. These findings extend previous research by focusing on the older segment of the mentally retarded population.

Splenic gonadal fusion

Splenogonadal fusion is a rare anomaly to be included in the differential diagnosis of testicular masses. It is often associated with congenital defects, including peromelia and micrognathia. A case is presented and the literature reviewed.

Sequential testicular biopsies in childhood acute lymphocytic leukemia

Between August 1978 and November 1981, 33 boys with acute lymphocytic leukemia (ALL) (26 non-T, 7 T-cell) younger than 16 years underwent bilateral wedge testicular biopsies at the time of initial diagnosis. Seven (4 non-T, 3 T-cell) demonstrated focal leukemic infiltrates. Rebiopsy after successful induction therapy without testicular irradiation showed eradication of leukemic infiltrates in five, persistent focal infiltrates in one, and a diffuse infiltrate in one. The two patients who had persistent leukemic involvement had a T-cell phenotype, and in one of them overt testicular disease developed 2 years later. All 33 patients were followed prospectively for a minimum of 3 years. Fifteen (14 non-T, 1 T-cell) remained in remission for 3 years and underwent another testicular biopsy before the cessation of therapy. Two patients, both non-T and both of whom were free of testicular involvement at diagnosis, showed testicular infiltrates at that time. Of the seven boys with positive specimens at diagnosis, only two remained disease-free for 3 years and showed no testicular involvement upon the completion of chemotherapy. In this study, microscopic testicular involvement by lymphoblasts occurred in 21% of newly diagnosed boys with ALL; this occurred only if the leukocyte count exceeded 25,000/microliter. These patients in general had a poor prognosis, probably reflecting the overall heavy tumor burden. However, it was not possible to predict accurately those patients who would have leukemic testicular infiltrates at the cessation of chemotherapy by performing biopsy of the testes at the time of initial diagnosis or after induction therapy.

Pretreatment testicular biopsy in childhood acute lymphocytic leukaemia

Between August, 1978, and March, 1981, 24 boys with acute lymphocytic leukaemia (ALL) (14 non-B-cell non-T-cell, 6 pre-B-cell, and 4 T-cell) underwent bilateral wedge testicular biopsy at initial diagnosis. All testes were of normal size. Histological analysis was performed independently by three pathologists, 4 (3 non-B non-T, and 1 pre-B) of 20 patients with non-T-cell ALL demonstrated testicular focal lymphoblastic involvement. Successful induction chemotherapy without concomitant testicular irradiation completely eradicated testicular infiltrates in all 4 patients. Only 1 of the 4 T-cell patients had pre-treatment testicular infiltrates. Unlike boys with non-B non-T leukaemia, attainment of bone-marrow remission in this patient was associated with persistent testicular disease. These preliminary data indicate that in patients with ALL of non-T-cell type, systemic induction chemotherapy eradicates the small testicular infiltrates of lymphoblasts. Prophylactic testicular irradiation in this group of patients does not seem to be warranted.

CYTOCHEMICAL STUDIES ON THE PROBLEM OF MACRONUCLEAR SUBNUCLEI IN TETRAHYMENA

DNA amounts in macronuclei and micronuclei of Tetrahymena pyriformis were measured by Feulgen microspectrophotometry. Assuming that the unreplicated micronucleus is diploid, the unreplicated macronucleus was found to contain approximately 45 times the haploid DNA amount. The relationship of these findings to the 45 independently assorting genetic subunits characterized by Allen and Nanney and their collaborators is discussed. The pattern of DNA synthesis in macro- and micronuclei during the cell cycle is also described.

DNA content of a chromosome of Trillium erectum: effect of cold treatment

The DNA (Feulgen) contents of a specific cold-treated (3 degrees C) chromosome and of a control (25 degrees C) were measured by means of photographic-plate microdensitometry. Despite marked morphological alterations in the cold-treated B chromosome of Trillium erectum, its DNA content was unchanged from that of the control.