Motor power differences within the first two weeks post-SCI in cervical spinal cord-injured quadriplegic subjects

The purpose of this study was to confirm the clinical impression that motor power significantly changed within the first 2 weeks after a spinal cord injury (SCI) and to determine the time for motor power assessment within the first 2 weeks post injury that best correlated with motor power determined 6 months post-SCI. Our hypothesis was that within the first 2 weeks postinjury, the manual muscle test (MMT) scores would change significantly from the < or = 24 h examination and that the post-24 h evaluations of strength would have a higher correlation with the 6 month measure of motor outcome than the evaluation of strength performed < or = 24 h after SCI. The biceps, extensor carpi radialis, triceps, flexor digitorum profundus, and interosseous muscle strength was measured in 40 subjects using the MMT (muscles graded 0/5 to 5/5) at < or = 24 h, 72 h, 1 week, 2 weeks, 3 months, and 6 months post-SCI. Upper extremity motor index scores (MIS) obtained at the four testing periods within 2 weeks of injury were analyzed using a Friedman analysis of variance with Duncan's post-hoc tests to identify significant differences. Separate analyses were performed on subgroupings of the total sample based on the strength of the most rostral key muscle having less than antigravity strength. There were three groups evaluated: initial MMT 0/5 (n = 22), initial MMT 1-1.5/5 (n = 17), and initial MMT 2-2.5/5 (n = 13).(ABSTRACT TRUNCATED AT 250 WORDS)

Issues in the development of social work information systems: the case of hospital social work departments

Information systems have been proposed as a valuable resource for promoting the efficient and effective operation of hospital social service departments. However, the development and implementation process must overcome the tensions inherent to collection and utilization of structured information by social work practitioners. These include the need for quantified data about qualitative phenomena, compatibility with existing work routines, compatibility with norms and perceptions of information needs at different levels, and potential versus actual utilization of the data. The authors examine these issues and present strategies for dealing with them, in the context of a project to develop a country-wide information system for social work departments in general hospitals in Israel.

Carbachol- and elevated Ca(2+)-induced translocation of functionally active protein kinase C to the brush border of rabbit ileal Na+ absorbing cells

Protein kinase C is involved in mediating the effects of elevated Ca2+ in ileal villus Na+ absorbing cells to inhibit NaCl absorption. The present studies were undertaken to understand the mechanism by which this occurs. The effects of carbachol and the calcium ionophore A23187, agents which elevate intracellular Ca2+ and inhibit NaCl absorption in ileal villus cells, were studied. Carbachol treatment of villus cells caused a rapid decrease in protein kinase C activity in cytosol, with an accompanying increase in microvillus membrane C kinase. Exposure of the villus cells to calcium ionophore also caused a quantitatively similar decrease in cytosol C kinase and increase in C kinase activity in the microvillus membrane. This increase caused by carbachol and Ca2+ ionophore was specific for the microvillus membrane. In fact, 30 s and 10 min after exposure of the cells to carbachol, basolateral membrane protein kinase C decreased, in a time-dependent manner; whereas 10 min of Ca2+ ionophore exposure did not alter basolateral C kinase. Exposure of villus cells to Ca2+ ionophore or carbachol caused similar increases in microvillus membrane diacylglycerol content. As judged by the ability to inhibit Na+/H+ exchange measured in ileal villus cell brush border membrane vesicles, the protein kinase C which translocated to the microvillus membrane was functionally significant. Inhibition of Na+/H+ exchange required ATP and was reversed by the protein kinase C antagonist H-7. In conclusion, the effect of carbachol and Ca2+ ionophore in regulation of ileal NaCl absorption is associated with an increase in microvillus membrane diacylglycerol content and functionally active protein kinase C. The effects of both carbachol and Ca2+ ionophore are different on brush border and basolateral membrane distribution of protein kinase C.

Randomization analysis of dental data characterized by skew and variance heterogeneity

Many distributions of dental variables exhibit positive skew and variance heterogeneity. Although the use of parametric tests on data with these disturbances usually does not pose a problem with respect to alpha error level, transformation of data sometimes increases power. Occasionally one or both of these expectations do not hold and it becomes problematic as to whether data should be transformed and which analyses should be considered valid. Simulated dental trials were conducted on independent samples (n = 25 per group) drawn from exponential distributions with the same or different population means, t-tests on raw, log, and square root transformed data; the Mann-Whitney-Wilcoxon ranking test; and a randomization test, all exhibited satisfactory levels of alpha error but the randomization test exhibited the greatest power followed closely by the t-test on raw scores. The present results demonstrate that the log transformation does not increase power for all forms of positively skewed data. Randomization tests, not being subject to normality and variance homogeneity assumptions, may yield greater confidence in validity in these cases. Some implications for analytical strategy are discussed.

Hyperfractionated radiation therapy in brain stem tumors. Results of treatment at the 7020 cGy dose level of Pediatric Oncology Group study #8495

Between May 1986 and February 1988, 57 patients were accrued to the second dose level of a Phase I/II Pediatric Oncology Group (POG) study exploring the use of hyperfractionated radiation therapy (HRT) in children with high-risk brain stem tumors. Local fields were treated with fraction sizes of 117 cGy given twice daily, with a minimum interfraction interval of 6 hours, to a total dose of 7020 cGy in 60 fractions over 6 weeks. Information regarding clinical status during HRT was available for 55 patients (44 [80%] improved, 6 remained stable, and 5 deteriorated). Results of initial and follow-up computed tomography (CT) scan and/or magnetic resonance imaging (MRI) were available for review for 52 patients. One patient had a complete response (CR) to treatment, 3 had a partial response (PR) (more than 50% response), and 40 remained stable, for a total response rate (CR + PR + stable) of 77%. Median time to disease progression was 6 months. Median survival time was 10 months. Survival rate was 39.6% (standard error [SE] = 6.6%) at 1 year and 23% (SE = 5.8%) at 2 years. Complications of treatment included an enhanced skin reaction in six patients and otitis media and/or externa in nine. One patient bled into tumor shortly after completion of HRT, and three had intralesional necrosis. Five patients continued taking steroids for protracted periods in the face of improved clinical and/or radiologic findings. Complications related to the use of steroids included opportunistic infections, impaired glucose tolerance, hypertension, osteoporosis, and significant mood changes. In no patient was there evidence of any late injury attributable to HRT. When compared with results of treatment with HRT at a lower dose level (6600 cGy), there appears to be a trend toward improved survival at 7020 cGy despite a less favorable patient population at the higher dose level. A second dose escalation to 7560 cGy in 60 fractions over 6 weeks has been implemented as planned.

Long-term consequences of CNS treatment for childhood cancer, Part II: Clinical consequences

Survival of children with brain tumors has improved over the past 20 years due in part to advances in surgery, radiation, and most recently chemotherapy. The long-term adverse effects of radiation and chemotherapy on these children is the subject of this report. In Part I, we reviewed the pathologic consequences of radiation, including leukoencephalopathy, radiation necrosis, and radiation myelopathy as well as the oncogenic effects of both radiation and chemotherapy. Part II addresses the long-term consequences of radiation and chemotherapy on intellectual and endocrine function. Risk factors for the development of both endocrinopathies and intellectual dysfunction include age at the time of radiation, volume and dose of radiation, site of tumor, and use of adjuvant chemotherapy, in particular methotrexate. Early recognition of these complications and treatment, where indicated, will measurably improve the quality-of-life of children treated for brain tumors. The national cancer groups are currently attempting to limit these long-term adverse effects by taking risk factors into account when formulating new treatment regimens.

Seizures and cerebritis associated with administration of OKT3

The development of a self-limited aseptic meningitis usually following the first dose administration of OKT3 therapy (an anti-pan-T-cell monoclonal antibody) in the treatment of renal transplantation rejection is well-documented. This report describes a patient with renal transplantation rejection who developed lateralizing seizures and cerebritis documented by magnetic resonance imaging. These findings were associated with the initiation of OKT3 therapy. To our knowledge, both cerebritis and seizures have not been described in association with OKT3 therapy.

Case report: pelvic actinomycosis with the development and resolution of a recto-sigmoid stricture

Actinomycosis is an unusual intra-abdominal infection, often mistaken for other conditions. We report a case associated with bilateral ureteric obstruction in which a recto-sigmoid stricture developed in previously normal bowel, followed by its complete resolution after treatment with antibiotics, as demonstrated by serial barium enema examinations.

Long-term consequences of CNS treatment for childhood cancer, Part I: Pathologic consequences and potential for oncogenesis

The pathologic changes associated with the treatment of cancer of the nervous system are reviewed. Computed tomographic, magnetic resonance imaging, and positron emission tomographic findings of these abnormalities are described, followed by discussion of the known histopathologic features. For the most part, pathologic effects are primary vascular and/or demyelinating. We review each of these effects at all levels of the neural axis. This review concludes with a discussion of the risk of developing second malignancies. Although this complication is infrequent, the likelihood that survivors of childhood cancer will develop a second malignancy is 10 times that of age-matched controls. This phenomenon in part relates to genetic predisposition, environmental factors, and host susceptibility. These qualifications not withstanding, most studies implicate central nervous system radiation with and without chemotherapy as the primary etiology for second malignancies.

Optic pathway tumors

Overall, the majority of patients with optic pathway tumors will have stable disease regardless if they are radiated or receive chemotherapy. This is a very indolent tumor system and, for the most part, not a threat to life. Because of this, issues regarding appropriate therapeutic approaches have yet to be resolved. Most agree that in patients with progressive visual loss and tumor limited to the orbit, surgery can be associated with a cure. The downside is the loss of vision associated with surgical extirpation. Radiation rather than surgery has been the mainstay of treatment for intracranial tumors of the optic pathway. To eliminate side effects associated with radiotherapy in the young child, chemotherapy may be the more considered choice. However, on escape of control, i.e., conversion of stable disease to progressive disease, radiotherapy should be considered.

The long-term effects of central nervous system therapy on children with brain tumors

Survivals of children with brain tumors have increased over the past 20 years owing to advances in surgery, radiation, and, most recently, chemotherapy. Unfortunately, central nervous system therapy, particularly radiation, may be associated with the development of dementia and learning disabilities, leukoencephalopathy, endocrinopathies, and oncogenesis. Recognition of these long-term effects of therapy is important as some are amenable to treatment and others may be prevented by modification of current treatment regimens.

Comparison of reflex modification procedures and auditory brainstem response in high-risk neonates

This study compared the results of reflex modification (RM)--an objective technique for assessing brainstem sensorineural processing--with those of auditory brainstem response (ABR) for a group of high-risk infants at comparable postconceptional ages. For the RM procedure, an eyeblink-eliciting tap to the glabella was presented either alone or accompanied by a brief 90dB SPL tone. 37 high-risk infants were tested with both RM and ABR at a mean postconceptional age of 37.3 weeks. Seven had an increased brainstem conduction time ('failed ABR') and eight did not exhibit significant reflex augmentation ('failed RM'), seven of whom also failed the ABR. These data provide evidence that sensory stimuli which affect the neural mechanisms responsible for the organization of the startle response and auditory processing share essential neural components.

Neural network approach to detection of metastatic melanoma from chromatographic analysis of urine

Chromatographic analysis of sera or urine is important in medicine for the evaluation of patients whose clinical status is associated with the presence of specific biochemical markers. Malignant melanoma has been a model for such studies due to the elaboration of melanin precursors and pigment as the tumor metastasizes. Computer-assisted methods for categorizing chromatographic data and clinical status are imperative due to the large number of detectable compounds and possible correlations. In addition, computer-based analysis of the data can readily extract patterns that are not obvious by visual inspection. In this paper, we present a neural network analysis of melanoma chromatographic and clinical data that categorizes subjects into normals, NED patients (No Evidence of Disease), and metastatic patients. The set of marker compounds for metastatic disease represents a significant advance over the correlations derived by visual inspection.

Rabbit ileal villus cell brush border Na+/H+ exchange is regulated by Ca2+/calmodulin-dependent protein kinase II, a brush border membrane protein

Ileal brush border membranes contain an endogenous Ca2+/calmodulin (CaM)-dependent protein kinase activity that modulates the activity of the apical membrane Na+/H+ exchanger. To further characterize this kinase, synapsin I, a substrate for Ca2+/CaM-dependent protein kinases, was added to preparations of ileal brush border membranes. In the presence of Ca2+/CaM, synapsin I was phosphorylated. Phosphopeptide mapping demonstrated that the addition of Ca2+/CaM to brush border membranes stimulated the phosphorylation of sites in synapsin I specific for Ca2+/CaM-dependent protein kinase II. Immunoblots containing brush border and microvillus membrane proteins were probed with an antibody that recognizes the 50-kDa subunit of rat brain Ca2+/CaM-dependent protein kinase II. This antibody labeled major and minor species of 50 and 53 kDa, respectively, with more labeling of the brush border than the microvillus membranes. Right-side-out ileal villus cell brush border vesicles were prepared containing CaM, ATP, and 350 nM free Ca2+. Na+/H+ exchange was inhibited by the presence of Ca2+/CaM/ATP within the vesicles. A 21-amino acid peptide inhibitor of CaM kinase II was enclosed within some vesicle preparations by freeze-thaw. The effect on Na+/H+ exchange of Ca2+/CaM/ATP was partially reversed by the inhibitor peptide. These studies demonstrate the presence of Ca2+/CaM-dependent protein kinase II in rabbit ileal villus cell brush border membranes. Based on the effect of a specific inhibitor peptide of Ca2+/CaM kinase II, it is concluded that this kinase inhibits brush border Na+/H+ exchange, which participates in the regulation of ileal Na+ absorption.

Patients' retrospective preference for extraction of asymptomatic third molars

The purpose of this study was to determine the personal utility of asymptomatic third molar removal in military patients. From 1 to 30 days (mean = 7.4) after the extraction of one or more third molars, 100 returning patients (all male, mean age = 20.1) were asked to respond to hypothetical questions concerning the extraction of asymptomatic third molars. If the likelihood of third molars ever having to be removed was given as 10%, 50%, and 100%, then 45%, 61%, and 88% of responses, respectively, showed preference for immediate extraction. When respondents chose to delay treatment until there was a problem, no likelihood group would tolerate more than 2.77 additional days of post-extraction pain before changing their preference to immediate extraction. 87% of respondents preferred extractions prior to a deployment which would make treatment delivery difficult, and 89% prior to becoming a civilian at which time treatment might no longer be free. The results indicate general acceptance of the strategy of prophylactic third molar removal among a sample of military patients who have undergone pre-treatment counseling and the surgical procedure. A question remains as to the personal utility that might be measured prior to surgery.

Sequential use of standard and ambulatory EEG in neonatal seizures

Adequate predictors do not exist to indicate whether seizures are likely to continue beyond the neonatal period. Thirteen neonates with seizures occurring after 7 days of age were evaluated with standard short-term electroencephalography (SEEG) during the initial seizures and with ambulatory EEG (AEEG) when each infant was within 37-44 weeks corrected age (i.e., gestational age plus chronologic age). Eight of 13 SEEGs, 10 of 13 AEEGs, and 12 of 13 with the combined use of both SEEGs and AEEGs accurately predicted the occurrence of seizures at 3-4 months corrected age. Results with SEEG and AEEG did not produce significantly different outcomes. Combined analysis of SEEG and AEEG produced significantly different results from those calculated when the two EEG types were analyzed independently (Z = 3.98, p less than 0.001). The findings indicate that the use of both of these tests may improve the ability to predict continued seizure activity in infants with neonatal seizures when compared to the use of each measure separately.

The blink reflex: maturation and modification in the neonate

The onset and development of the delayed blink response, elicited by a tap to the glabella, and its modification by an acoustic stimulus (tone), were studied longitudinally in 36 healthy preterm and 43 term infants. Blink amplitude increased with gestational age. By term postconceptional age, the responses of the preterm infants to tap alone, and to both tap and tone, were not significantly different from those of the term infants. These results suggest that neurological development, as reflected by the blink reflex and its modification, proceeds in an orderly, sequential fashion and that the mechanisms affecting these brainstem processes are not altered by environmental influences.

Altered brainstem sensory processing as assessed by reflex modification procedures in infants at risk for apnea

Reflex modification procedures were used to test sensory processing in premature infants to examine the relationship between respiratory abnormalities and brainstem neuronal function. A total of 73 premature infants at risk for apnea and/or infants receiving methylxanthine therapy was given a 12-h pneumocardiogram and reflex modification test at a comparable postconceptional age, before discharge. Reflex modification was tested using a controlled eyeblink-eliciting tap to the glabella presented either alone or with a 1 kHz 90-dB SPL tone. The amplitude of the glabellar tap eyeblink and acoustically modified blink were lower in infants discharged on cardiac/apnea monitors (n = 36) than in the unmonitored group (1.44 and 1.59 volts versus 2.15 and 2.39 V, p less than 0.005, respectively). At follow-up, 12 monitored infants had clinically significant apnea after discharge. The records of this subgroup of infants revealed a significantly lower augmentation of the glabellar eyeblink response when compared to all infants screened for respiratory abnormalities and to the other monitored babies (p less than 0.01). The data suggest that abnormalities of the ventilatory pattern and occurrence of clinical apnea in preterm infants may in some measure be related to acoustic sensory processing, implying an alteration of brainstem neuronal function and organization.

Role of calcium and calmodulin in the regulation of the rabbit ileal brush-border membrane Na+/H+ antiporter

In rabbit ileum, Ca2+/calmodulin (CaM) appears to be involved in physiologically inhibiting the linked NaCl absorptive process, since inhibitors of Ca2+/CaM stimulate linked Na+ and Cl- absorption. The role of Ca2+/CaM-dependent phosphorylation in regulation of the brush-border Na+/H+ antiporter, which is believed to be part of the neutral linked NaCl absorptive process, was studied using purified brush-border membrane vesicles, which contain both the Na+/H+ antiporter and Ca2+/CaM-dependent protein kinase(s) and its phosphorprotein substrates. Rabbit ileal villus cell brush-border membrane vesicles were prepared by Mg precipitation and depleted of ATP. Using a freezethaw technique, the ATP-depleted vesicles were loaded with Ca2+, CaM, ATP and an ATP-regenerating system consisting of creatine kinase and creatine phosphate. The combination of Ca2+/CaM and ATP inhibited Na+/H+ exchange by 45 +/- 13%. This effect was specific since Ca2+/CaM and ATP did not alter diffusive Na+ uptake, Na+-dependent glucose entry, or Na+ or glucose equilibrium volumes. The inhibition of the Na+/H+ exchanger by Ca2+/CaM/ATP was due to an effect on the Vmax and not on the Km for Na+. In the presence of CaM and ATP, Ca2+ caused a concentration-dependent inhibition of Na+ uptake, with an effect 50% of maximum occurring at 120 nM. This Ca2+ concentration dependence was similar to the Ca2+ concentration dependence of Ca2+/CaM-dependent phosphorylation of specific proteins in the vesicles. The Ca2+/CaM/ATP-inhibition of Na+/H+ exchange was reversed by W13, a Ca2+/CaM antagonist, but not by a hydrophobic control, W12, or by H-7, a protein kinase C antagonist. We conclude that Ca2+, acting through CaM, regulates ileal brush-border Na+/H+ exchange, and that this may be involved in the regulation of neutral linked NaCl absorption.

Elevated intracellular Ca2+ acts through protein kinase C to regulate rabbit ileal NaCl absorption. Evidence for sequential control by Ca2+/calmodulin and protein kinase C

Calcium/calmodulin is involved in the regulation of basal rabbit ileal active Na and Cl absorption, but the mechanism by which elevated intracellular Ca2+ affects Na and Cl transport is unknown. To investigate the roles of the Ca2+/calmodulin and protein kinase C systems in ileal NaCl transport, two drugs, the isoquinolenesulfonamide, H-7, and the naphthalenesulfonamide, W13, were used in concentrations that conferred specificity in the antagonism of protein kinase C (60 microM H-7) and Ca2+/calmodulin (45 microM W13), respectively, as determined using phosphorylation assays in ileal villus cells. W13 but not H-7 stimulated basal active NaCl absorption. H-7 inhibited changes in Na and Cl absorption caused by maximal concentrations of Ca2+ ionophore A23187 and carbachol and serotonin, secretagogues that act by increasing cytosol Ca2+, while W13 had no effect. In contrast, neither H-7 nor W13 altered the change in NaCl transport caused by the cyclic nucleotides 8-Br-cAMP and 8-Br-cGMP. These data suggest that: (a) basal rabbit ileal NaCl absorption is regulated by the Ca2+/calmodulin complex and not by protein kinase C; (b) the effect of elevating intracellular Ca2+ to decrease NaCl absorption is mediated via protein kinase C but not by Ca2+/calmodulin; (c) the effects of protein kinase C are not overlapping or synergistic with those of Ca2+/calmodulin on either basal absorption or on the effects of increased Ca2+; and (d) neither Ca2+/calmodulin nor protein kinase C are involved in the effects of cAMP and cGMP on ileal active NaCl transport.

Sensory processing in the term and preterm infant: use of reflex modification procedures

The present study uses the glabellar reflex and reflex modification procedures to assess acoustic and tactile sensory processing capabilities in the human neonate. Fourteen term infants and 28 clinically stable preterm infants were given identical test paradigms. Augmentation testing consisted of a 16 V dc tap presented simultaneously with a 90 dB SPL tone; inhibition testing consisted of a 16 V tap preceded 900 msec. by an identical tap. All 14 term infants showed augmentation with 8 of 14 at p less than 0.05 level and eleven of 14 showed significant inhibition at the 900 msec intertap interval. However, only 12 of 28 preterm infants demonstrated significant augmentation and none showed reliable inhibition. These data indicate that areas of the central nervous system that process sensory stimuli are not fully developed at the time of birth even in the term infant. Further, the neural system for augmentation and inhibition may be independent of each other.

The significance of MRI abnormalities in children with neurofibromatosis

We prospectively evaluated 47 children with neurofibromatosis to determine whether the previously reported high signals on magnetic resonance imaging (MRI) (prolonged T2) correlated with CT, brainstem auditory evoked responses (BAER), EEG, clinical examinations, cognitive abilities, or seizure disorder. Thirty percent of children had a history of seizures and 70% had either learning disabilities or mental retardation. Overall, 74% had an abnormal MRI examination. Sixty-two percent had high signals (prolonged T2) on T2-weighted images. Abnormal signals were located primarily in the basal ganglia, brainstem, and cerebellum. Twenty-five percent of patients had abnormal EEGs, 28% had abnormal CTs, and 27% had abnormal BAER examinations. The abnormal signals on MRI did not consistently relate to findings on CT, BAER, EEG, school placement, or clinical examination. The abnormal signals presumably reflect areas of abnormal brain parenchyma, either hamartomas, heterotopias, or local areas of brain dysplasia.

Treatment of CNS neoplasms in childhood by the Pediatric Oncology Group

The incidence of brain tumors in children under 15 years of age in the United States is 2.4/100,000. Based upon a US population of approximately 60 million black and white children, there are only 1,200-1,500 newly diagnosed causes of CNS neoplasia diagnosed in children each year in the US. These relatively small numbers, the large geographic dispersion, and the multitude of histologic types, make it unlikely that all but a few medical centers can develop a large experience with this diverse group of tumors. The Brain Tumor Committee (BTC) of the Pediatric Oncology Group was formed, in part, to address this problem. Each of the four goals of the BTC will be addressed separately. A justification for the rationale for each goal is given, following which there is a discussion of how each goal is being met.

Habituation of the startle reflex in posttraumatic stress disorder

The authors investigated habituation of the eye-blink component of the startle reflex to repeated affectively neutral tactile and auditory stimuli in nine subjects with posttraumatic stress disorder and nine controls. Each group showed rapid habituation in both tactile and auditory modalities.

Value of a routine follow-up endoscopy program for the detection of recurrent colorectal carcinoma

Four hundred fifty-two patients with surgically resected colon or rectal cancer were evaluated to determine the incidence of intraluminal recurrences and the utility of a routine endoscopy screening program for detecting such recurrences. At the time of analysis, recurrent disease was found in 86 of 380 colon cancer patients and 21 of 72 rectal cancer patients. Local recurrence, defined as tumor within 400 cm2 of the primary, was present in 38 of 86 colon, and 11 of 21 rectal cancer patients. Of those 49 local recurrences, 15 were intraluminal, 6 of which were initially detected by a follow-up endoscopy program. Time to diagnosis, stage of disease, and survival were similar for patients whose lesions were detected by routine endoscopy versus those found by other means. New primary (metachronous) lesions defined as an intraluminal lesion occurring at least 5 cm beyond the surgical anastomosis were identified in six colon cancer patients and no rectal cancer patients. Of these six lesions, four were discovered during routine endoscopy. Thus, a routine follow-up endoscopy program is an important tool for the detection of intraluminal recurrence of colon and rectal cancer in patients who have undergone curative resection. However, routine follow-up endoscopy should not be the sole method of follow-up, since the incidence of intraluminal recurrence is small, and may initially be detected by other means in the majority of cases.

Prognostic criteria for experimental protocols in pediatric brainstem gliomas

Prognostic criteria were developed to select children with high-risk brainstem gliomas for experimental treatment with hyperfractionated radiation. Patients were required to have (a) tumors confined primarily to the brainstem; (b) positive findings in two of three groups of neurologic signs (cranial nerve deficits and long-tract and cerebellar signs), and (c) symptom duration of less than 6 months. The 18-month survival of only 1 of 33 evaluable patients suggests that these criteria did in fact select tumors of poor prognosis. Such noninvasive predictors provide a valuable means of selecting for experimental treatment those children who would not be expected to benefit from standard therapies for malignant brainstem tumors. These criteria do not require routine biopsy for prognostic purposes, and avoid exposing the children to unnecessary risk.

Regulation of the rabbit ileal brush-border Na+/H+ exchanger by an ATP-requiring Ca++/calmodulin-mediated process

Brush-border vesicles purified from rabbit ileal villus cells were used to evaluate how Ca++/calmodulin (CaM) regulates the neutral linked NaCl absorptive process, part of which is a Na+/H+ exchanger. After freezing and thawing to allow incorporation of macromolecules into the vesicles, the effect of Ca++/CaM on brush-border Na+ uptake with an acid inside pH gradient, and on Na+/H+ exchange was determined. Freezing and thawing vesicles with 0.85 microM free Ca++ plus 5 microM exogenous CaM failed to alter Na+/H+ exchange as did the addition of exogenous ATP plus an ATP regenerating system, which was sufficient to elevate intravesicular ATP to 47 microM from a basal level of 0.4 microM. However, the combination of Ca++/CaM plus ATP inhibited Na+ uptake in the presence of an acid inside pH gradient and inhibited Na+/H+ exchange, while Na+ uptake in the absence of a pH gradient was not altered. This effect required a hydrolyzable form of ATP, and did not occur when the nonhydrolyzable ATP analogue, AMP-PNP, replaced ATP. Under the identical intravesicular conditions used for the transport studies, Ca++ (0.85 microM) plus exogenous CaM (5 microM), in the presence of magnesium plus ATP, increased phosphorylation of five brush-border peptides. These data are consistent with Ca++/CaM acting via phosphorylation to regulate the ileal brush-border Na+/H+ exchanger.

Prospective intellectual testing in children with brain tumors

Sixteen children with brain tumors received prospective intellectual evaluations with a follow-up of 2 to 5 years. All patients were treated with surgery and radiation and 5 received chemotherapy. Most of the children remained within the normal range of intelligence, but intelligence quotient (IQ) scores declined over time. Learning disabilities were present in 15 of 16 children after radiation, and 11 required special educational services. Risk factors associated with decline in IQ appear to be young age at time of radiation and adjuvant chemotherapy.

Reflex modification audiometry: assessment of acoustic sensory processing in the term neonate

Behavioral and physiological work in animals and adult humans have established the sensitivity of various procedures and allowed delineation of the neuroanatomical pathways involved in sensory processing. Herein we used the glabellar reflex and reflex modification procedures to assess acoustic sensory processing capabilities in the term newborn infant. The eyeblink-eliciting device consisted of a miniature solenoid which could deliver a controlled tap. A photoreflective densitometer attached to a TDH-39 earphone assessed the eyeblinks. A total of 98 term infants was studied to determine how a response to a reflex-eliciting event (tap) was modified (either augmented or inhibited) by a mild exteroceptive stimulus (tone) which was presented at an appropriate lead interval. Ninety adult subjects were given identical testing procedures and their data were compared to that of the infants. The results of this study showed that newborn infants reliably exhibited an eyeblink response after a tap to the glabella. With fixed intensity tones, frequencies from 1 to 4 kHz produced equivalent amounts of reflex augmentation in infants and adult subjects. Blink amplitude increased as a function of increased tap and tone intensity in both infants and adults. State change was shown to affect the amplitude of the reflexive eyeblink, but not the augmentation effect. However, neonates failed to show inhibition to either acoustic lactile stimuli at an interstimulus interval that produced significant inhibition in the adult. These data indicate that reflex modification procedures provide an objective assessment of acoustic sensory processing in the term neonate.(ABSTRACT TRUNCATED AT 250 WORDS)

Distributions of periodontal attachment levels. Mathematical models and implications

Distributions of periodontal attachment levels at probing sites within patients have traditionally been used in clinical diagnosis and treatment planning. Progression from mild to moderate to severe disease is generally associated with increasing magnitudes of attachment loss at greater percentages of sites. Recent analyses of distributions of periodontal attachment levels have suggested three general patterns of loss defined by: (1) loss at less than about one third of all sites, (2) more widespread disease with multiple peaks and (3) normally distributed loss with virtually all sites being affected. In attempting to stimulate these three patterns using a model based on the burst theory of periodontal attachment loss, divergent assumptions about burst magnitude, frequency, and possible local immunity were required. These findings were used to support the hypothesis that distinctly different disease processes are associated with the different patterns of attachment level. In the present investigation an alternative model was developed which was theoretically consistent with the view that the three patterns reflect arbitrary stages in a continuous disease "aging" process. Simple assumptions concerning attachment loss probabilities and rates enabled the generation of attachment level distributions that matched all three patterns previously attributed to separate disease processes, depending only upon the duration of the process.

Effects of Ca2+, theophylline and promethazine on protein phosphorylation in intact cells of rabbit ileum. Correlation with active Na and Cl absorption

The effects of Ca2+, theophylline and promethazine on the phosphorylation of microvillus membrane proteins have been studied in rabbit ileal epithelial cells, using intact cell phosphorylation techniques followed by purification of microvillus membranes, separation of peptides by two-dimensional polyacrylamide gel electrophoresis, and quantitation of phosphorylation by computerized densitometry of autoradiograms. The Ca2+ ionophore A23187 caused increased phosphorylation of four and possibly five polypeptides; theophylline increased phosphorylation of three peptides, two of which had the same Mr and pI values as the peptides altered by the Ca2+ ionophore; promethazine decreased the phosphorylation of one of the peptides increased by Ca2+ ionophore. The phosphorylated peptides, which respond similarly to more than one agent which affect ileal Na and Cl absorption, could be involved in the regulation of NaCl absorption either as transport proteins or regulators of transport proteins.

Performance of papillary muscles from the aging spontaneously hypertensive rat: temporal changes in isometric contraction parameters

Myocardial mechanics in the male spontaneously hypertensive rat (SHR) and Wistar-Kyoto rat (WKY) at 18 months of age were studied. Left ventricular hypertrophy was documented in the SHR by an increase in left ventricle/body weight and left ventricle/tibial length ratios when compared to the WKY (P less than 0.001). Isolated left ventricular papillary muscles were studied at 28 degrees C while contracting 12 times/min at the apex of the length-tension curve. Active and passive length-tension relations were measured at relatively early (65 +/- 3 min) and late (200 +/- 5 min) times following sacrifice. No significant differences in passive length-tension relations between strains were observed. Between early and late measurements, a significant decrease in passive tension within the length spectrum 89-100% Lmax occurred in both SHR and WKY, accompanied by a significant increase in passive stiffness (P less than 0.01, SHR; P less than 0.001, WKY). Isometric performance was measured at relatively early (81 +/- 3 min) and later (190 +/- 5 min) times following sacrifice. Strain differences in active muscle performance were of a greater electromechanical delay time (EMD) (P less than 0.05, early: P less than 0.001, late) and time-to-peak tension (TPT) (P less than 0.001, late) in SHR compared to WKY. Between early and late measurements, decreases in EMD (P less than 0.01, SHR; P less than 0.001, WKY), TPT (P less than 0.001; P less than 0.001), the half-time of relaxation (P less than 0.001; P less than 0.001), and the resting tension (P less than 0.01; P less than 0.001) were observed, and the maximum rate of fall of tension increased (P less than 0.01; P less than 0.01). We conclude that studies must be precisely referenced from the time of sacrifice of the animal in order to accurately evaluate the effects of experimental hypertrophy on isolated muscle performance. No evidence for the depression of papillary muscle isometric performance was seen in the 18-month SHR when compared to the WKY, although prolonged EMD and TPT were observed.

Freeze-thaw and high-voltage discharge allow macromolecule uptake into ileal brush-border vesicles

High-voltage discharge or one cycle of freeze-thawing are shown to transiently permeabilize rabbit ileal brush-border membrane vesicles to macromolecules. Uptake of the radiolabeled macromolecule dextran, mol wt 70,000, used as a marker for vesicle permeability, was determined by a rapid filtration technique, with uptake defined as substrate associated with the vesicle and releasable after incubation of vesicles with 0.1% saponin. Dextran added immediately after electric shock (2,000 V) or at the beginning of one cycle of freeze-thawing was taken up approximately eightfold compared with control; with both techniques, the concentration of dextran after being taken up into the vesicles was similar to that in the incubation medium, suggesting attainment of equilibrium. ATP also was taken up into freeze-thawed vesicles, whereas there was no significant uptake into control vesicles. The increase in vesicle permeability was reversible, based on Na-dependent D-glucose uptake being decreased when studied 5 but not 15 min after electric shock, and was not significantly decreased after completion of one cycle of freeze-thawing. In addition, adenosine 3',5'-cyclic monophosphate and Ca2+-calmodulin-dependent protein kinase activity were similar in control vesicles and vesicles exposed to high-voltage discharge or freeze-thawing. Also, vesicles freeze-thawed with [32P]ATP demonstrated increased phosphorylation compared with nonfrozen vesicles, while freeze-thawing did not alter vesicle protein as judged by Coomassie blue staining. These techniques should allow intestinal membrane vesicles to be used for studies of intracellular control of transport processes, for instance, studies of protein kinase regulation of transport.

Inhibition of the eyeblink reflex in the human infant

In human adults the eyeblink elicited by a given stimulus can be inhibited if that stimulus is preceded by another stimulus at an appropriate lead interval. In the present work, pairs of eyeblink-eliciting stimuli separated by 300-1200 msec were presented to sleeping preterm and full-term infants as well as to adults. Preterm infants did not exhibit reliable inhibition at any interval. Full-term infants did so, but they required longer interstimulus intervals than were needed for inhibition in the adult subjects. Results imply that the neural systems that mediate reflex inhibition are functional at birth, but that they are relatively slow to act.

Problems in identifying "bursts" of periodontal attachment loss

A theory of periodontal attachment loss which postulates discrete bursts of activity has recently been proposed. This paper identifies several problems in the interpretation of the experimental data that have been used to support the burst model. Major obstacles to valid inferences are associated with the following: substantial measurement error, insufficient evidence supporting a dichotomy of disease state and the use of diagnostic decision criteria with undesirable properties. The nature of these problems is discussed from the framework of receiver operating characteristic (ROC) analysis. "Bursts" of attachment loss can be explained, in whole or in part, by these factors in the absence of real change. Types of research evidence that would offer more compelling support for the burst model are identified. The questionable validity of evidence supporting the burst model may impact on both the direction of future research efforts and clinical applications.