Psychosocial aspects of a Tay-Sachs screening clinic.

The authors administered questionnaires to participants in a Tay-Sachs screening clinic. They received 322 responses. Although the majority of the respondents expressed anxiety about the possibility that they might be carriers, most indicated that this anxiety brought them to the clinic. The authors conclude that a well-publicized and well-organized screening clinic can function successfully and deal with the issue of anticipated loss without producing mass fear. An important factor in their clinic was the fact that they were able to offer an alternative to a Tay-Sachs child through amniocentesis.

Significance of luminal plasma layer resistance in arterial wall oxygen supply.

Previous analyses of the arterial wall oxygen supply system have assumed that a cell-free layer of plasma next to the endothelium is the major transport barrier in the lumen. Using a computer simulation, we have quantitatively tested this assumption. Our results show that oxygen diffusion gradients extend significantly into the flowing blood well beyond any plasma layer and that the major luminal transport resistance lies in the flowing blood and not in the plasma layer. The simulation was also employed to compute the effect of a reported 50% drop in plasma oxygen diffusivity. This rather large reduction did significantly lower oxygen levels within the arterial wall tissue. Whether such large reductions in diffusivity ever actually occur in human plasma is a subject of current controversy.

Carbon monoxide-induced arterial wall hypoxia and atherosclerosis.

The elevated carbon monoxide level found in tobacco smokers has been suggested as one etiologic factor linking it with atherosclerosis. Unquestionably carbon monoxide does induce some arterial wall hypoxia, which has been established as an atherogenic factor, but without knowing the extent and location of this hypoxia the importance of this mechanism could not previously be assessed. Carbon monoxide acts both by inducing hypoxemia and shifting the oxyhemoglobin equilibrium curve, with these effects acting on the oxygen transport system from both the luminal blood and the vasa vasorum. We have studied this system using a computer simulation of the human arterial wall and found significant, mid-medial hypoxia with blood carbon monoxide levels routinely found in smokers. Because these levels fluctuate, the hypoxia they induce would be expected to be uncompensated by increased vascularization and therefore potentially represent a much more significant factor in atherogenesis than chronic hypoxia alone.

Radioiododeoxyuridine in cancer therapy: an in vitro approach to developing in vivo strategies.

UNLABELLED: Studies were undertaken to determine the relationship between IUdR concentration and the duration of radiolabeled IUdR treatment required to incorporate the equivalent of a D(o) dose in vitro and to estimate the treatment parameters necessary to incorporate a killing dose in vivo. METHODS: W138 (normal human) and HeLa (human cancer) cells were grown axenically or in co-culture. The three cultures were treated for 5 days with 18.5 kBq/ml [125I]IUdR. After treatment, the cells were subcultured and grown for 7 days in medium without [125I]IUdR. In separate experiments, Chinese hamster ovary cells (CHO) were labeled with various ratios of radiolabeled (125I) and nonradiolabeled IUdR and the mole rate of IUdR incorporation in double-stranded DNA was measured. Mitotically selected CHO cells were incubated without treatment until > 98% were in S phase. At this time, the cells were labeled for 15 min with several concentrations of either [123I]IUdR or [125I]IUdR and their colony survival was measured. RESULTS: After incubation with [125I]IUdR, selective eradication of HeLa cells from a co-culture of W138 and HeLa cells was achieved. The incorporation of IUdR into DNA of CHO cells, although the sum of a series of enzymatic steps, has the appearance of and can be analyzed as a Michaelis-Menton type curve. The maximum rate of IUdR incorporation (Vmax) is 4.424 x 10(-18) mol/min and the substrate concentration at 1/2 Vmax (K) is 3.717 x 10(-6) M IUdR. The Do dose rates for [123I]IUdR and [125I]IUdR, respectively, are 18.78 and 1.88 initial decays/cell/hr. CONCLUSION: The D(o) dose for *IUdR can be determined from survival curves versus the mole amount of *IUdR incorporated in DNA. To be effective as an in vivo treatment it will be necessary to manipulate the IUdR delivery time, concentration and volume in a manner that assures that the target cells incorporate a cytocidal dose of *IUdR.

Evaluation of a new blood autotransfusion device.

A new autotransfusion device was evaluated in dogs. The device uses citrate phosphate dextrose as the blood anticoagulant and automatically delivers the agent in a ratio approximating that found in banked blood. Bleeding, aspiration, and autotransfusion of approximately 3 estimated blood volumes produced small changes in hematologic and coagulation studies. Blood electrolytes stayed within normal ranges. Activated clotting times stayed within normal range after autotransfusion of 2 blood volumes but increased slightly after 3 blood volume transfusions. No significant histopathologic changes were found in any organ system. Rapid infusion of citrated blood causes myocardial depression, which can be reversed by giving calcium. Overall performance of the device was excellent, suggesting further documentation in a clinical setting and evaluation with human blood.

G2 cells: progression delay and survival.

The progression of Chinese hamster ovary (CHO) G2 cells into mitosis and their survival was measured after X-ray doses up to 4.0 Gy. S-phase cells were prevented from reaching mitosis by labeling with 125IUdR for 10 min prior to irradiation of the exponentially growing monolayer of cells. Mitotic cells, located past the radiation-induced division delay transition point, did not suffer a delay and were selected separately prior to the recovery of the G2 cells. The results show that (1) up to 400 min after radiation only 55% of the G2 cells recovered after about 2.5 Gy; (2) the progression delay of the G2 cells that recovered was 52.5 min/Gy; and (3) the survival curve D0 for these cells, 2.45 Gy, indicated a radioresistant population.

Targets for radiation-induced cell death: when DNA damage doesn't kill.

Chinese hamster ovary (CHO) K1 and radiosensitive CHO irs-20 cells were synchronized in S phase and labeled for 10 min with 5-[(125)I]-iodo-2'-deoxyuridine ((125)IdU). The cells were washed, incubated in fresh medium for 1 h for incorporation of the intracellular radionucleotides into DNA, and then frozen (-80 degrees C) for accumulation of (125)I decays. At intervals after freezing, when the cells had accumulated the desired number of decays, aliquots of the frozen cells were thawed and plated to determine survival. The survival curves for K1 and irs-20 cells were similar from 100% to 30% survival. At higher (125)I doses (more decays/cell), the survival of K1 cells continued to decline exponentially, but the survival of X-ray-sensitive irs-20 cells remained at approximately 30% even after the cells had accumulated 1265 decays/cell. The results contradict the notion that increased DNA damage inevitably causes increased cell death. To account for these findings, we propose a model that postulates the existence of a second radiation target. According to this model, radiation damage to DNA may be necessary to induce cell death, but DNA damage alone is not sufficient to kill cells. We infer from the survival response of irs-20 cells that damage to a second (non-DNA) structure is involved in cell death, and that this structure directly affects the repair of DNA and cell survival.

Cell progression after selective irradiation of DNA during the cell cycle.

Chinese hamster ovary cells were labeled with [125I]iododeoxyuridine (125IUdR, 0.1184 MBq/ml for 20 min) and the labeled mitotic cells were collected by selective detachment ("mitotic shake off"). The cells were pooled, plated into replicate flasks, and allowed to progress through the cell cycle. At several times after plating, corresponding to G1, S, late S, and G2 plus M, cells were cooled to stop cell cycle progression and to facilitate accumulation of 125I decays. Evaluation of cell progression into the subsequent mitosis indicated that accumulation of additional 125I decays during G1 or S phase was eight to nine times less effective in inducing progression delay than decays accumulated during G2. The results support our previous hypothesis that DNA damage per se is not responsible for radiation-induced progression delay. Instead, 125I-labeled DNA appears to act as a source of radiation that associates during the G2 phase of the cell cycle with another radiosensitive structure in the cell nucleus, and damage to the latter structure by overlap irradiation is responsible for progression delay (M. H. Schneiderman and K. G. Hofer, Radiat. Res. 84, 462-476 (1980].

Association between the division delay target and DNA late in the cell cycle.

The precise cell cycle time of association between labeled DNA (the radiation source) and the non-DNA cell structure whose damage is responsible for radiation-induced division delay was measured. Mitotic cells were selected from a monolayer of Chinese hamster ovary cells for 80 min (nine shakes) to establish the rate of cell progression into mitosis. The cell monolayers were then exposed to 0.1295 MBq/ml 125IUdR for 10 min to label the cells in S phase. After pulse labeling, mitotic cell selection was continued for various times (between 0 and 120 min) before 125I decays were accumulated at 4 degrees C. After 2 h in the cold, the cells were rewarmed and the selection of mitotic cells was continued. (Cooling had a small, transient affect on subsequent cell progression.) As the time between labeling and cooling was increased, the fraction of cells selected in mitosis decreased, indicating that an increasing proportion of 125I-labeled cells had entered a sensitive phase of the cell cycle where 125I decays are particularly effective in producing radiation-induced division delay. It is hypothesized that during this sensitive period (from -25 to +90 min of the S/G2 boundary), the labeled DNA comes into sufficiently close contact with a non-DNA structure to facilitate damage to this structure by overlap irradiation from 125I decays in the DNA.

The presence of DNA breaks and the formation of chromatid aberrations after incorporation of 125IdUrd may be necessary but are not sufficient to block cell cycle progression in G2 phase.

Cell progression into mitosis and chromatid aberration frequencies were compared in two Chinese hamster ovary (CHO) cell lines after incorporation of 125IdUrd. Asynchronous, exponentially growing populations of CHO K1 and the DNA repair-deficient, radiation-sensitive CHO irs-20 cells were compared after a 10-min exposure to 14.8 kBq/ml 125IdUrd. Essentially no differences were seen for either end point between the cells of the two cell lines. As the cells in S phase at the time of labeling entered the mitotic cell selection window, the number of mitotic cells of each cell line declined to approximately 60% of the respective unlabeled control. Chromosome analysis of the mitotically selected cells indicated an 125I decay-dependent increase in the number of chromatid aberrations in cells of both cell lines. The appearance of aberrations together with the known rates of production and rejoining of DNA double-strand breaks show that cells are able to progress through G2 phase and into mitosis in the presence of such breaks. The data suggest that DNA damage may be necessary, but is not sufficient to cause a radiation-induced blockade of cell progression through G2 phase.

Cell cycle-based purging of lymphoma cells from bone marrow harvests using radioiodinated 5-iodo-2'-deoxyuridine.

Minimal residual disease in lymphoma patients is a major problem in the clinical management of their cancer. High-dose chemotherapy followed by autologous bone marrow transplantation has been used to treat the disease. However, residual lymphoma may be reintroduced along with the marrow if it is present in the bone marrow harvest. In this report we describe results of experiments testing the efficacy of 5-[125I]-iodo-2'-deoxyuridine (125IdU) for purging murine RAW117 large cell lymphoma cells (Joshi et al., Oncology 44, 180-185, 1987; Cancer Res. 47, 3551-3557, 1987) from bone marrow in a relevant animal model. Donor BALB/c mice were injected with murine RAW117 cells and euthanized on day 13, and their bone marrow that had been contaminated with tumor cells was harvested and treated in vitro with 125IdU or nonradioactive 127IdU (control). Nine of 10 mice receiving 127IdU-treated bone marrow contaminated with tumor cells died at an average of 17 days after injection. In comparison, 9 of 10 mice injected with 125IdU-treated bone marrow contaminated with tumor cells were still alive after 82 days. In addition, the 125IdU treatment did not diminish the formation of hematopoietic progenitor cell colonies in normal mouse and human peripheral blood stem cells.

An in vitro 125IUdR-release assay for measuring the kinetics of cell death.

A radionuclide release assay for measuring the in vitro kinetics of cell death has been developed. CHO cells were labelled for 24 h with 3.0 hBq/ml of [125I] iododeoxyuridine (125IUdR) and the fate of the labelled cells and their progeny was monitored at daily intervals by measuring the rate of 125I release. Prelabelling with 125IUdR did not alter the plating efficiency, the doubling time or the selection of mitotic cells. The rate of 125I release from labelled (but otherwise untreated) CHO cells was approximately equal to 4% day. Treatment with a lethal dose of X-rays (30 Gy), heat (46 degrees C, 1 h), cold (-90 degrees C, 1 h) or the antibiotic Geneticin (300 micrograms/ml, continuously) resulted in the release of greater than 99% the 125I activity associated with the cells. Cell death was rapid after heating or freezing, and delayed after treatment with X-rays or Geneticin. The results illustrate the efficacy of the 125I release assay for measuring the kinetics of cell death in mammalian tissue culture cells.

Effect of pulsatility on oxygen transport to the human arterial wall.

Oxygen transfer in fully-developed, pulsating, laminar flow in rigid and distensible tubes was simulated as part of a study of vessel-wall hypoxia and atherogenesis. The model used for the computations is based on dimensions and flows in the human thoracic aorta. The pulsatile velocity fields employed are based on those of Womersley with the modification that the radial convection is written relative to the moving wall. Womersley-type pulsatility, superposed on an axial Poiseuille flow, was found to negligibly affect oxygen transport to the wall. Caution should be exercised, however, in extending this conclusion to the complex pulsatility in actual living vessels.

Blunt injuries to the extracranial cerebral vessels associated with spine fractures.

Injury of the extracranial carotid or vertebral artery with associated spine fractures is a rare but documented entity. In this article, four cases are examined in which patients suffered axial fractures after motor vehicle accidents and subsequently were found to have pathology in one or more of the extracranial arteries. Misdiagnosis is a common complication because symptoms from this are often attributable to closed head injury. Early detection and treatment, however, are essential. As many as 40% of the cases reported have permanent neurologic deficit. Although cerebral angiography remains the diagnostic gold standard, other modalities (eg, transcranial doppler and magnetic resonance angiography) continue to be examined. The treatment of these lesions remains controversial. A variety of surgical procedures may be applicable depending on the time between the injury and the onset of symptoms, the location of the vascular injury, and the rapidity of diagnosis. Anticoagulation therapy appears to play a large role in the management of patients with injury of the extracranial carotid or vertebral artery.

The pars defect as a pain source. A histologic study.

STUDY DESIGN: Tissue from the pars defects of six adult patients with symptomatic spondylolysis and spondylolisthesis was obtained at surgery. A histologic study was conducted to identify and characterize neural elements in this tissue. OBJECTIVES: To determine if nociceptive nerve endings were present within the pars defect of patients with symptomatic spondylolysis. SUMMARY OF BACKGROUND DATA: The origin of back pain in patients with spondylolysis remains uncertain. The defect in the pars interarticularis has been implicated as a possible pain source. METHODS: The soft tissue from the pars defect was obtained at surgery. A modified gold chloride stain was used to prepare the tissue for histologic examination. Tissue blocks were sectioned and studied under light microscopy. RESULTS: Neural elements were found in all specimens examined. Free nerve endings believed to have nociceptive function were identified in all specimens. The density of neural elements varied between specimens. CONCLUSIONS: The finding of neural elements, including free nerve endings within the pars defect tissue, suggests that the pars defect may be a source of back pain in some patients with symptomatic spondylolysis.

Magnetic resonance imaging in the diagnosis of disc degeneration: correlation with discography.

One hundred and one disc levels in 36 patients with low-back pain were studied with magnetic resonance imaging (MRI) (T2-weighted) sagittal images and conventional roentgenographic discography to detect early disc degeneration. Thirty-nine discs also were evaluated after discography with roentgenographic CT MRI findings were compared with discography results. MRI was 99% accurate in predicting normality or abnormality as determined by discography. Changes in disc signal on MRI accurately reflected the presence or absence of degenerative changes seen on discography in patients with low-back pain. Clinically, MRI is a useful technique for detecting early disc degeneration and for assessing the affected disc level and adjacent levels in patients with low-back pain and spondylolithesis.

The transition zone above a lumbosacral fusion.

STUDY DESIGN: The clinical and radiographic effect of a lumbar or lumbosacral fusion was studied in 42 patients who had undergone a posterolateral fusion with an average follow-up of 22.6 years. OBJECTIVE: To examine the long-term effects of posterolateral lumbar or lumbosacral fusion on the cephalad two motion segments (transition zone). SUMMARY OF BACKGROUND DATA: It is commonly held that accelerated degeneration occurs in the motion segments adjacent to a fusion. Most studies are of short-term, anecdotal, uncontrolled reports that pay particular attention only to the first motion segment immediately cephalad to the fusion. METHODS: Forty-two patients who had previously undergone a posterolateral lumbar or lumbosacral fusion underwent radiographic and clinical evaluation. Rate of fusion, range of motion, osteophytes, degenerative spondylolisthesis, retrolisthesis, facet arthrosis, disc ossification, dynamic instability, and disc space height were all studied and statistically compared with an age- and gender-matched control group. The patient's self-reported clinical outcome was also recorded. RESULTS: Degenerative changes occurred at the second level above the fused levels with a frequency equal to those occurring in the first level. There was no statistical difference between the study group and the cohort group in the presence of radiographic changes within the transition zone. In those patients undergoing fusion for degenerative processes, 75% reported a good to excellent outcome, whereas 84% of those undergoing fusion for spondylolysis or spondylolisthesis reported a good to excellent outcome. CONCLUSION: Radiographic changes occur within the transition zone cephalad to a lumbar or lumbosacral fusion. However, these changes are also seen in control subjects who have had no surgery.

Dynamic EMG analysis of torque transfer in professional baseball pitchers.

Fifteen professional baseball pitchers underwent active pitching motion analysis of the abdominal oblique, rectus abdominis, lumbar paraspinous and gluteus maximus muscles bilaterally via surface electrode evaluation. Baseline resting and isometric maximum values were obtained and active data referenced against these for comparison. The muscle activity then was measured during the pitching sequence and analyzed in each of the five pitching phases. The abdominal oblique, lumbar paraspinous and rectus abdominis contralateral to the pitching arm and the ipsilateral gluteus maximus all had increases in activity level of 75 to 100% during the active pitching motion. Using these data indicating specific muscle group patterns with clinical and performance data, we hope to minimize injuries and maximize pitching performance.

Oxygen fields induced by recessed and needle oxygen microelectrodes in homogeneous media.

Computer simulations of the operation of both the recessed and conically-shaped needle type microelectrodes were developed. The accurate portrayal of their geometries was greatly facilitated by the use of specialized three dimensional orthogonal coordinate systems with coordinate surfaces coincident with the geometry of the problem. From the simulations, calculations were made of the induced PO2 fields, oxygen sensitivities, stirring artifacts, measurement errors, and time constants.

An approach to families of acting-out adolescents--a case study.

Certain types of acting-out in the adolescent express the feelings of deprivation of the parental pair in a maladaptive aggressive way. Family therapists have attempted to convert the acting-out behavioral disorders into an effective state, i.e., make the family aware of their feelings of deprivation by focusing on the aggressive component. In many instances, the family becomes depressed and then interrupts or terminates treatment. The authors feel that this is due to the therapist's interpretations which bring about the depressive state via guilt provocation. The family understands the interpretations as meaning "You are bad to have your adolescent offspring behave in such a way". The therapist is thus seen as the family's collective super-ego. In order to prevent premature termination, the therapist should instead help the members of the family to become more conscious of their loving, "welfare" feelings for one another. In this way the self-esteem of the family is increased, which then permits more verbal action of aggressive feelings--thus a decrease in the acting-out, and ultimately an increase in the capacity to mourn. It should be pointed out, however, that in certain families, the technique described is not applicable. In these cases, although there is acting-out, the families are unable to draw on sufficient good experiences together which are necessary to elicit positive feeling for one another. The absence of readily available "welfare" feelings is of diagnostic and prognostic significance and differentiates the disorganized, sociopathic or schizophrenic family from the acting-out of parental deprivation as illustrated in this paper.