Showing papers by "University of Maryland, Baltimore published in 1986"

Positron emission tomography reveals elevated D2 dopamine receptors in drug-naive schizophrenics

Abstract: In postmortem studies of patients with schizophrenia, D2 dopamine receptors in the basal ganglia have been observed to be more numerous than in patients with no history of neurological or psychiatric disease. Because most patients with schizophrenia are treated with neuroleptic drugs that block D2 dopamine receptors in the caudate nucleus, it has been suggested that this increase in the number of receptors is a result of adaptation to these drugs rather than a biochemical abnormality intrinsic to schizophrenia. With positron emission tomography (PET), the D2 dopamine receptor density in the caudate nucleus of living human beings was measured in normal volunteers and in two groups of patients with schizophrenia--one group that had never been treated with neuroleptics and another group that had been treated with these drugs. D2 dopamine receptor densities in the caudate nucleus were higher in both groups of patients than in the normal volunteers. Thus, schizophrenia itself is associated with an increase in brain D2 dopamine receptor density.

Pelvic fractures: value of plain radiography in early assessment and management.

Abstract: Assessment of pelvic fractures in severely traumatized, clinically unstable patients presents a diagnostic problem. Traditional plain-radiographic classifications of the fracture are of limited preoperative value to the surgeon who must apply corrective force in opposition to the original force vector causing the fracture. Computed tomographic scanning is an effective method of examining the pelvis but is time consuming and may be impractical in cases of severe injury. In a retrospective analysis of the plain radiographs of 142 cases of pelvic fracture, four patterns of force were identified, presenting distinctive, recognizable radiographic appearances. These patterns are anteroposterior compression, lateral compression, vertical shear, and a complex pattern. The resulting classification of pelvic fracture, based on radiographic and clinical findings, correlates with associated injury to soft-tissue structures and enables the surgeon to begin corrective procedures rapidly.

Mechanisms of arrhythmogenic delayed and early afterdepolarizations in ferret ventricular muscle.

Abstract: Drug-induced triggered arrhythmias in heart muscle involve oscillations of membrane potential known as delayed or early afterdepolarizations (DADs or EADs). We examined the mechanism of DADs and EADs in ferret ventricular muscle. Membrane potential, tension and aequorin luminescence were measured during exposure to elevated [Ca2+]0, strophanthidin and/or isoproterenol (to induce DADs), or cesium chloride (to induce EADs). Ryanodine (10(-9)-10(-6) M), an inhibitor of Ca2+ release from the sarcoplasmic reticulum, rapidly suppressed DADs and triggered arrhythmias. When cytoplasmic Ca2+-buffering capacity was enhanced by loading cells with the Ca2+ chelators BAPTA or quin2, DADs were similarly inhibited, as were contractile force and aequorin luminescence. In contrast to DADs, EADs induced by Cs were not suppressed by ryanodine or by loading with intracellular Ca2+ chelators. The possibility that transsarcolemmal Ca2+ entry might produce EADs was evaluated with highly specific dihydropyridine Ca channel agonists and antagonists. Bay K8644 (100-300 nM) potentiated EADs, whereas nitrendipine (3-20 microM) abolished EADs. We conclude that DADs and DAD-related triggered arrhythmias are activated by an increase in intracellular free Ca2+ concentration, whereas EADs do not require elevated [Ca2+]i but rather arise as a direct consequence of Ca2+ entry through sarcolemmal slow Ca channels.

Avenues for entry of peripherally administered protein to the central nervous system in mouse, rat, and squirrel monkey.

Abstract: Pathways traversed by peripherally administered protein tracers for entry to the mammalian brain were investigated by light and electron microscopy. Native horseradish peroxidase (HRP) and wheat germ agglutinin (WGA) conjugated to peroxidase were administered intranasally, intravenously, or intraventricularly to mice; native HRP was delivered intranasally or intravenously to rats and squirrel monkeys. Unlike WGA-HRP, native HRP administered intranasally passed freely through intercellular junctions of the olfactory epithelia to reach the olfactory bulbs of the CNS extracellularly within 45-90 minutes in all species. The olfactory epithelium labeled with intravenously delivered HRP, which readily escaped vasculature supplying this epithelium. Blood-borne peroxidase also exited fenestrated vessels of the dura mater and circumventricular organs. This HRP in the mouse, but not in the other species, passed from the dura mater through patent intercellular junctions within the arachnoid mater; in time, peroxidase reaction product in the mouse brain was associated with the pial surface, the Virchow-Robin spaces of vessels penetrating the pial surface, perivascular clefts, and with phagocytic pericytes located on the abluminal surface of superficial and deep cerebral microvasculature. Blood-borne HRP was endocytosed avidly at the luminal face of the cerebral endothelium in all species. WGA-HRP and native HRP delivered intraventricularly to the mouse were not endocytosed appreciably at the abluminal surface of the endothelium; hence, the endocytosis of protein and internalization of cell surface membrane within the cerebral endothelium are vectorial. The low to non-existent endocytic activity and internalization of membrane from the abluminal endothelial surface suggests that vesicular transport through the cerebral endothelium from blood to brain and from brain to blood does not occur. The extracellular pathways through which probe molecules enter the mammalian brain offer potential routes of passage for blood-borne and air-borne toxic, carcinogenic, infectious, and neurotoxic agents and addictive drugs, and for the delivery of chemotherapeutic agents to combat CNS infections and deficiency states. Methodological considerations are discussed for the interpretation of data derived from application of peroxidase to study the blood-brain barrier.

Antiviral effect of an oligo(nucleoside methylphosphonate) complementary to the splice junction of herpes simplex virus type 1 immediate early pre-mRNAs 4 and 5.

Abstract: Selective inhibition of regulatory immediate early (IE) genes of herpes simplex virus type 1 (HSV-1) should inhibit virus growth. Treatment of HSV-1-infected cells with the oligo(nucleoside methylphosphonate) d(TpCCTCCTG) (deoxynucleoside methylphosphonate residues in italic), which is complementary to the acceptor splice junction of HSV-1 IE pre-mRNA 4 and 5, before (1-24 hr) or at the time of infection caused a dose-dependent inhibition in virus replication. Virus titers were decreased 50% and 90% in cells treated with 25 microM and 75 microM oligomer, respectively; at 300 microM, a 99% reduction in virus production was observed. Viral DNA synthesis was reduced 70-75% and there was a 90% reduction in synthesis of viral proteins, including other IE species and viral functional (130-kDa major DNA-binding) and structural (glycoprotein gB) proteins. In the same concentration range, d(TpCCTCCTG) caused a minimal reduction (0-30%) in protein synthesis and growth rates (less than 40%) of uninfected cells. The data suggest that oligo(nucleoside methylphosphonate)s may be effective in antiviral chemotherapy.

Intraspinal transplantation of embryonic spinal cord tissue in neonatal and adult rats.

Abstract: Fetal rat spinal cord tissue was obtained on gestational day 14 (E14) and transplanted into 2-4-mm-long intraspinal cavities produced by partial spinal cord lesions in adult and neonatal rats. At regular post-transplantation intervals, light and electron microscopy, autoradiographic demonstration of tritiated thymidine labelling, and immunocytochemical localization of glial fibrillary acidic protein (GFAP) were used to identify surviving donor tissues and to study their differentiation and extent of fusion with recipient spinal cords. In some experiments, wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was also employed to examine whether neurons within the grafts projected axons into the host spinal cord and vice versa. Lastly, immunocytochemistry was used to determine whether any supraspinal serotoninergic (5-HT) axons from the host extended into the transplants. Over 80% of the grafts survived in lesions of both the neonatal and adult rat spinal cord for periods of 1-16 months (duration of experiment), and considerable maturation of donor tissue was evidenced, which even included the appearance of some topographical features of the normal spinal cord. Many of the transplants extended the entire length of the lesion, and were often closely apposed to the injured surfaces of the recipient spinal cords without an intervening dense glial scar. At post-transplantation intervals of 2-4 months, injection of WGA-HRP into the host spinal cord (5 mm from the transplant in adult animals or as much as 20 mm in neonatal recipients) demonstrated retrogradely labelled neurons and anterogradely labelled axons in the grafts. Likewise, injecting WGA-HRP into transplants in adult recipients resulted in labelling of neurons in adjacent segments of the host spinal cord; some labelled axons, derived from donor neurons, were also present in neighboring spinal gray matter. Finally, immunocytochemistry revealed 5-HT-like immunoreactive fibers in transplants that had been prelabelled with tritiated thymidine. These observations demonstrate the potential of embryonic spinal cord transplants to replace damaged intraspinal neuronal populations and to restore some degree of anatomical continuity between the isolated rostral and caudal stumps of the injured mammalian spinal cord.

Screening for depression in stroke patients: the reliability and validity of the Center for Epidemiologic Studies Depression Scale.

Abstract: This study examined the inter-observer reliability and validity of the Center for Epidemiologic Studies Depression Scale (CES-D) as a measure of depressive symptomatology in stroke patients, and its utility as a screening tool for depression in this population. The CES-D Scale is a brief questionnaire originally designed for use in community surveys. Twenty-seven non-aphasic patients enrolled in the Stroke Data Bank at the University of Maryland were interviewed by a research nurse using the CES-D. On the same day, each patient was independently evaluated by a research assistant using a psychiatric battery for depression and measures of cognitive, physical, and social functioning. Forty-one percent (11/27) of the patients were depressed according to clinical criteria for major or minor depression. With a cutpoint corresponding to the upper (most severe) 20% in community surveys, the CES-D Scale picked up 73% (8/11) of the depressed patients. In this sample no nondepressed patient scored over 16 on the CES-D (no false positives). The CES-D Scale scores correlated significantly with the other depression measures (r = .57 to r = .82, p less than .002) and did not correlate with the measures of cognitive, physical, or social functioning. Based on 24 patients who received a CES-D Scale score from both the nurse and the research assistant, inter-rater reliability was high (r = .76, p less than .001). Thus, the CES-D was found to be reliable and valid as a screening tool for assessing depression in stroke patients.

Neural tissue transplants rescue axotomized rubrospinal cells from retrograde death

Abstract: Rubrospinal tract cells undergo massive retrograde degeneration following spinal cord damage in newborn rats (Prendergast and Stelzner, J. Comp. Neurol. 166:163-172, '76b). In the current study, fetal spinal cord tissue (E12-14) was grafted into midthoracic spinal cord lesions in newborn rats (less than 72 hours old) in order to determine whether such transplants could modify the response of the immature host central nervous system (CNS) to axotomy. These transplants grew, differentiated, and formed extensive areas of apposition with the recipient spinal cords. Counts of red nucleus (RN) neurons indicated a significant loss of RN neurons in animals with lesion alone, but a rescuing of most of these cells if a transplant was placed into the lesion site. In fact, the number of neurons in animals with lesions and transplants was not significantly different from control animals. Horseradish peroxidase injected 10-15 mm caudal to the transplant (at 1-12 months post-transplantation) labeled neurons within the transplant and RN neurons contralateral to the spinal cord lesions and transplant. In animals with spinal cord lesion but no transplant, only the unaxotomized RN was labeled. Thus, spinal cord transplants prevented the massive retrograde cell death of immature axotomized rubrospinal neurons. Some of these rescued neurons projected to the host spinal cord caudal to the transplant.

Single-dose half-body irradiation for palliation of multiple bone metastases from solid tumors. Final Radiation Therapy Oncology Group report.

Abstract: This is the final analysis of Protocol #78-10 which explored increasing single-doses of half-body irradiation (HBI) in patients with multiple (symptomatic) osseous metastases. When given as palliation, HBI was found to relieve pain in 73% of the patients. In 20% of the patients the pain relief was complete; over two thirds of all patients achieved better than 50% pain relief. The HBI pain relief was dramatic with nearly 50% of all responding patients doing so within 48 hours and 80% within one week from HBI treatment. Furthermore, the pain relief was long-lasting and continued without need of retreatment for at least 50% of the remaining patient's life. These results compare favorably with those obtained by the Radiation Therapy Oncology Group (RTOG) using several conventional daily fractionated schemes on similar patients in a prior study (RTOG #74-02). HBI achieves pain relief sooner and with less evidence of pain recurrence in the irradiated area than conventionally treated patients. The most effective and safest of the HBI doses tested were 600 rad for the upper HBI and 800 rad for the lower or mid-HBI. Increasing doses beyond these levels did not increase pain relief, duration of relief, or achieved a faster response; however, the increase in dose was associated with a definite increase in toxicity. Single-dose HBI was well tolerated with no fatalities seen among 168 treated patients. A comprehensive premedication program has proven to decrease the acute radiation syndrome to very acceptable levels. There were excellent responses found in practically all tumors treated, but especially breast and prostate among which over 80% of all patients experienced pain relief, 30% in a complete fashion. Single-dose HBI emerges as one of the safest, fastest, and more effective palliative tools for intractable cancer pain in modern radiation oncology.

Cytochemical identification of cerebral glycogen and glucose‐6‐phosphatase activity under normal and experimental conditions: I. Neurons and glia

Abstract: Reliable ultrastructural techniques are applied for cytochemical identification of glycogen and localization of glucose-6-phosphatase (G6Pase) activity within neurons and glia of the adult mammalian CNS. Modulations in the cerebral localizations of glycogen and G6Pase activity are identified during various experimental conditions (i.e., salt-stress, fasting, and trauma). The cytochemical reaction for demonstration of G6Pase activity implies that the enzyme acts as a phosphohydrolase to convert glucose-6-phosphate to glucose. The degradation of glycogen in vivo is one source of glucose-6-phosphate as a substrate for G6Pase. Glycogen is preserved by perfusion-fixation of the brain with 2% glutaraldehyde-2% formaldehyde. Chopper sections of this material are postfixed in buffered 1% osmium tetroxide-1.5% potassium ferrocyanide, which serves as a contrast stain for glycogen, or in buffered 1% osmium tetroxide. Plastic-embedded ultrathin sections of CNS tissue postfixed in 1% osmium tetroxide are stained for glycogen with periodic acid–thiocarbohydrazide-silver protein. Intracellular glycogen appears as electron-dense isodiametric particles and, under normal and experimental conditions, is most abundant within astrocytes. Neuronal glycogen is sparse to negligible normally but appears increased within specific neuronal populations during stressful states. Optimal preservation of G6Pase activity in the brain is obtained by brief perfusion-fixation with 2% glutaraldehyde. Tissue sections are incubated in a modified Leskes medium containing glucose-6-phosphate or mannose-6-phosphate as substrate and lead nitrate. Utilizing the Gomori lead capture technique, G6Pase reaction product is localized within the lumen of the endoplasmic reticulum (ER) and related organelles (i.e., nuclear envelope, Golgi complex) of perikarya, dendrites, and glia. The ER in axons and axon terminals fails to express G6Pase activity under normal conditions but does so in some neurons exhibiting a degenerating appearance. A transient, cytochemical decrease in G6Pase activity may occur within some perikarya during stressed conditions. The results indicate that within neurons and glia of the adult CNS cytochemical stains are well suited for ultrastructural identification of glycogen and localization of G6Pase activity. Modulations in glycogen particle concentration and in localization of G6Pase activity in the neuron can occur in response to conditions that influence the energy metabolism of the cell. These modulations may reflect differences in the regional utilization of glucose as an energy-producing substrate and as a derivative of glycogenolysis within the CNS.

Cytochemical identification of cerebral glycogen and glucose-6-phosphatase activity under normal and experimental conditions. II. Choroid plexus and ependymal epithelia, endothelia and pericytes.

Abstract: Intracellular glycogen and glucose-6-phosphatase (G6Pase) activity were identified cytochemically within epithelia of the choroid plexus and ependyma of the cerebral ventricles including the median eminence and area postrema, the cerebral endothelium and pericytes from control, salt-stressed and fasted adult mice. Identification of glycogen was obtained by employing osmium tetroxide-potassium ferrocyanide and the periodic acid-thiocarbohydrazide-silver protein technique as ultrastructural contrast stains. A lead-capture method was used to localize G6Pase activity with glucose-6-phosphate or mannose-6-phosphate as substrate. Cerebral G6Pase functions predominantly as a phosphohydrolase to convert glucose-6-phosphate to glucose. Some glucose-6-phosphate in vivo may be derived from the breakdown of glycogen stores. Within the sampled cell types, presumptive glycogen appeared as electron-dense, isodiametric particles scattered throughout the cytoplasm. Reaction product for G6Pase activity was localized consistently within the lumen of the nuclear envelope and endoplasmic reticulum and frequently within an outer saccule of the Golgi complex under normal conditions. Choroid plexus epithelia from stressed mice exhibited a qualitative increase in cytoplasmic glycogen and a decrease in G6Pase activity; the other cell types did not express demonstrable alterations in glycogen concentration and G6Pase activity. The results indicate that glycogen and G6Pase activity are prevalent within non-neural cells of the adult mammalian CNS. Glucose utilization in the choroid plexus epithelium may be altered by stressful conditions that influence the functional activity of this cell.

Heterogeneity of insulin responses: phases leading to Type 2 (non-insulin-dependent) diabetes mellitus in the rhesus monkey

Abstract: To determine the natural history of the development of Type 2 (non-insulin-dependent) diabetes mellitus, basal plasma insulin and glucose levels and responses to intravenous glucose tolerance tests were determined over a period of 6 years in 42 adult male rhesus monkeys (Macaca mulatta). Among the 28 obese monkeys (percent body fat > 22%) over the age of 10 years, 9 developed overt Type 2 diabetes (fasting plasma glucose, > 7.8 mmol/l; and reduced glucose disappearance rates, KG < 1.5), and 14 monkeys have shown progressive changes which suggest that they may also become diabetic. Application of a highly constant antecedent diet and a consistent 16-h fast minimized experimental variability, and permitted the identification of 8 phases in the progression from normal lean young adult to overt Type 2 diabetes. The earliest changes which could be detected were a slight increase followed by a progressive rise in fasting plasma insulin levels and an increased insulin secretion in response to a glucose stimulus. These events preceded by several years the onset of a gradual deterioration of glucose tolerance. We found that hyper-, normo-, or hypoinsulinaemia could be associated with normoglycaemia or varying degrees of hyperglycaemia; however, the prospective longitudinal study of individual monkeys clearly identified this apparent heterogeneity of plasma insulin and glucose levels as reflecting sequential changes in a continuum of events preceding or accompanying the development of impaired glucose tolerance and Type 2 diabetes mellitus.

Relationship between force and intracellular [Ca2+] in tetanized mammalian heart muscle

Abstract: To determine features of the steady state [Ca2+]-tension relationship in intact heart, we measured steady force and intracellular [Ca2+] ([Ca2+]i) in tetanized ferret papillary muscles. [Ca2+]i was estimated from the luminescence emitted by muscles that had been microinjected with aequorin, a Ca2+-sensitive, bioluminescent protein. We found that by raising extracellular [Ca2+] and/or by exposing muscles to the Ca2+ channel agonist Bay K 8644, tension development could be varied from rest to an apparently saturating level, at which increases in [Ca2+]i produced no further rise in force. 95% of maximal Ca2+-activated force was reached at a [Ca2+]i of 0.85 +/- 0.06 microM (mean +/- SEM; n = 7), which suggests that the sensitivity of the myofilaments to [Ca2+]i is far greater than anticipated from studies of skinned heart preparations (or from previous studies using Ca2+-sensitive microelectrodes in intact heart). Our finding that maximal force was reached by approximately 1 microM also allowed us to calculate that the steady state [Ca2+]i-tension relationship, as it might be observed in intact muscle, should be steep (Hill coefficient of greater than 4), which is consistent with the Hill coefficient estimated from the entire [Ca2+]i-tension relationship derived from families of variably activated tetani (6.08 +/- 0.68; n = 7). Finally, with regard to whether steady state measurements can be applied directly toward understanding physiological contractions, we found that the relation between steady force and [Ca2+]i obtained during tetani was steeper than that between peak force and peak [Ca2+]i observed during physiological twitches.

Ca2+ release from endoplasmic reticulum is mediated by a guanine nucleotide regulatory mechanism.

Abstract: Ca2+ accumulation and release from intracellular organelles is important for Ca2+ -signalling events within cells1,2. In a variety of cell types, the active Ca2+-pumping properties of endoplasmic reticulum (ER) have been directly studied using chemically per-meabilized cells3–6. The same preparations have been extensively used to study Ca2+ release from ER, in particular, release mediated by the intracellular messenger inositol 1,4,5-trisphosphate (InsP3)1,2,5,7–12. So far, these studies and others using microsomal membrane fractions2,11,13–15 have revealed few mechanistic details of Ca2+ release from ER, although a recent report16 indicated that InsP3-mediated Ca22+ release from liver microsomes may be dependent on GTP. In contrast to the latter report, we describe here the direct activation of a specific and sensitive guanine nucleotide regulatory mechanism mediating a substantial release of Ca2+ from the ER of cells of the neuronal cell line N1E-115. These data indicate the operation of a major new Ca2+ gating mechanism in ER which is specifically activated by GTP, deactivated by GDP, and which appears to involve a GTP hydrolytic cycle.

Induction or prevention of immunopathological disease by cloned cytotoxic T cell lines specific for lymphocytic choriomeningitis virus

Abstract: Cloned lymphocytic choriomeningitis virus (LCMV)-specific cytotoxic T lymphocyte (CTL) lines were prepared from spleens of 129/J (H-2b) mice immunized 7-9 months earlier with LCMV (UBC strain), or of C57BL/10J (H-2b) mice immunized 4 to 5 weeks earlier with LCMV (Armstrong strain). One uncloned and 3 cloned cytotoxic T cell lines were assessed for their respective abilities to produce, or protect against, fatal disease upon transfer to appropriate recipients or to induce specific footpad-swelling reaction. The effects of all lines were essentially identical. In recipient mice acutely infected with LCMV and immunosuppressed either by irradiation (750-990 rds) or treatment with cyclophosphamide, cloned T cells administered intracerebrally (i.c.) caused a convulsive disease and death within 1-4 days. No disease was produced when the same CTL were transferred to uninfected recipients or when they had been frozen and thawed prior to transfer to infected recipients. When admixed with 500 plaque-forming units of LCMV and transferred i.c. to immunocompetent H-2b mice, the T cell clones prevented overt disease. Allogeneic (H-2k) recipients of this same admixture all developed typical LCM disease as did H-2b recipients of the admixture after T cells had been frozen and thawed. Inoculation of cloned CTL into preinfected footpads induced a specific footpad-swelling reaction, which reached maximum levels after about 36 h. Irradiated and infected recipients of cloned LCMV-specific T cells showed the footpad-swelling reaction only when they had been reconstituted with bone marrow cells. In contrast, cloned T cells induced LCM disease in i.c. infected and irradiated mice independent of bone marrow reconstitution. These findings indicate that both fatal LCMV-induced neurologic disease and protection against it are mediated directly by virus-specific CTL.

Antagonistic interactions of transforming growth factors in the regulation of granulosa cell differentiation

Abstract: The role of transforming growth factors (TGFs) in the acquisition of granulosa cell aromatase activity was investigated in vitro in a primary culture of granulosa cells harvested from immature, diethylstilbestrol-treated rats. Basal aromatase activity, as assessed by the generation of radioimmunoassayable estrogen, was negligible, remaining unaffected by treatment with either TGF alpha or TGF beta applied by themselves at the 10 ng/ml dose level. Whereas treatment with FSH produced a substantial increase in the extent of aromatization, concurrent treatment with TGF beta (0.01-10 ng/ml) resulted in dose-dependent augmentation of the FSH effect with an apparent median effective dose of 224 +/- (SE) 32 pg/ml (ca. 9 pM), and a maximal effect 3.6-fold greater than that induced by FSH alone. In contrast, concomitant treatment with TGF alpha (0.01-10 ng/ml) resulted in dose-dependent attenuation of FSH action with an apparent median inhibitory dose of 330 +/- (SE) 40 pg/ml (ca. 60 pM), and a maximal inhibitory effect of 91 +/- (SE) 2%. However, combined treatment with identical (10 ng/ml) maximally effective doses of both TGFs had little or no effect on the FSH-stimulated accumulation of estrogen, suggesting mutual neutralization by the opposing actions of these peptides. Further evaluation of the antagonistic interaction of the TGFs revealed it to be dose-dependent in that maximally effective doses of TGF alpha (10 ng/ml) partially overcame the stimulation of aromatase activity brought about by relatively low (less than 0.3 ng/ml) but not higher (greater than 1 ng/ml) concentrations of TGF beta, thereby shifting the TGF beta dose-response curve to the right. Treatment with either TGF had no significant effect on granulosa cell DNA content or synthesis, plating efficiency or viability. Taken together, these findings suggest that picomolar concentrations of exogenously provided TGF alpha TGF beta exert potent but diametrically opposed effects on the acquisition of granulosa cell aromatase activity and that the interaction between these two peptides is antagonistic in nature. Our findings further suggest that these direct cytodifferentiative effects of the TGFs may represent intrinsic novel properties of these peptides distinct from their well-established role in the regulation of cellular growth.

Long-term use of narcotic/antidepressant medication in the management of phantom limb pain

Abstract: The successful management of 5 consecutive patients with intractable phantom limb pain is described. The main therapy is a combination of a narcotic and antidepressant. Medication remained effective during the average observation time of 22 months. There were no signs of habituation or addiction. We conclude that narcotics can be safely and successfully utilized for long-term management of phantom limb pain.

Absolute oral bioavailability of ciprofloxacin.

Abstract: We evaluated the absolute bioavailability of ciprofloxacin, a new quinoline carboxylic acid, in 12 healthy male volunteers. Doses of 200 mg were given to each of the volunteers in a randomized, crossover manner 1 week apart orally and as a 10-min intravenous infusion. Half-lives (mean +/- standard deviation) for the intravenous and oral administration arms were 4.2 +/- 0.77 and 4.11 +/- 0.74 h, respectively. The serum clearance rate averaged 28.5 +/- 4.7 liters/h per 1.73 m2 for the intravenous administration arm. The renal clearance rate accounted for approximately 60% of the corresponding serum clearance rate and was 16.9 +/- 3.0 liters/h per 1.73 m2 for the intravenous arm and 17.0 +/- 2.86 liters/h per 1.73 m2 for the oral administration arm. Absorption was rapid, with peak concentrations in serum occurring at 0.71 +/- 0.15 h. Bioavailability, defined as the ratio of the area under the curve from 0 h to infinity for the oral to the intravenous dose, was 69 +/- 7%. We conclude that ciprofloxacin is rapidly absorbed and reliably bioavailable in these healthy volunteers. Further studies with ciprofloxacin should be undertaken in target patient populations under actual clinical circumstances.

Clinical correlation with anti-peripheral-nerve myelin antibodies in Guillain-Barré syndrome.

Abstract: Anti-peripheral-nerve myelin antibodies (anti-PNM Ab) can be detected in the serum of all patients with acute-phase Guillain-Barre syndrome (GBS) thus far tested. Correlation of the titer of this antibody with the clinical course would help to establish a role for the humoral immune system in the pathophysiology of GBS. In this study, anti-PNM Ab levels were measured in serial serum samples of 7 patients with GBS with an assay that detects antibodies bound to peripheral nerve myelin antigens by fixation of the first component of complement. Although the titers of anti-PNM Ab detected in these patients varied between 0 and 256 U/ml, the antibody titer was always highest on admission (35 to 256 U/ml) and rapidly declined during a one-to-three-week period. Disappearance of antibodies or very low levels of them correlated with cessation of progression and considerable clinical improvement as documented by increased pulmonary vital capacity and muscular strength. Low but measurable antibody titers (5 to 12 U/ml) were frequently found up to four months following the acute neurological deficit. The close temporal relationship between anti-PNM Ab titer and the clinical course in GBS suggests that antibody most likely participates through complement activation in peripheral nerve demyelination.

Carboplatin (NSC-241-240): an active platinum analog for the treatment of squamous-cell carcinoma of the head and neck.

Abstract: Carboplatin (CBDCA, Bristol-Meyers, New York) is a second generation platinum analog. Preclinical and phase I clinical studies have indicated a different spectrum of toxicity compared with the parent compound. In order to study the activity of carboplatin against cancer of the head and neck, 31 patients with recurrent or metastatic disease (30 squamous-cell and one adenoid cystic carcinoma) were treated with doses of 60 to 80 mg/m2 administered daily by intravenous (IV) bolus injections for five days, repeated at every 4- to 5-week intervals. In most cases, treatment was administered on an outpatient basis. Eight patients (26%; 95% confidence interval, 12% to 45%) had complete (CR) or partial responses (PR) with a median duration of 4.5 months. Moderate bone marrow suppression was the main toxicity. Mild nausea and vomiting was unusual and no neuro- or nephrotoxicity were seen. These preliminary data suggest that carboplatin has activity against advanced squamous-cell carcinoma of the head and neck compar...

Estrogen alters the acquisition of seizures kindled by repeated amygdala stimulation or pentylenetetrazol administration in ovariectomized female rats.

Abstract: Summary: Ovariectomized female rats received estradiol (E2) replacement by means of subcutaneous silastic capsules (10% E2 in cholesterol). E2-replaced rats required fewer daily amygdala stimulations to develop fully kindled seizures as compared with ovariectomized rats implanted with cholesterol-only capsules. Other rats were injected with pentylenetetrazol (PTZ), 40 mg/kg i.p., every 48 h. E2-replaced rats showed a progressive increase in convulsive severity from minimal responses after the first injection to tonic convulsions after eight injections. Most rats without E2 replacement failed to progress past clonic convulsive responses after 22 injections. The results support a marked influence of E2 on seizure processes as demonstrated in two different models of seizure acquisition. RESUME Des rates ovariectomisees ont recu de l'estradiol (E2) de remplacement par l'intermediaire de capsules en silastique sous-cutanees (10% d'E2 dans du cholesterol). Chez les rates recevant E2 il fallait moins de stimulations quotidiennes de l'amygdale pour obtenir des crises completes par embrasement que chez des rates ovariectomisees chez qui les capsules implantees contenaient seulement du cholesterol. Chez d'autres rates on a injecte du pentylenetetrazol (PTZ), 40 mg/kg intra-peritoneal toutes les 48 H. Chez les rates recevant E2 on observait une augmentation progressive de la severite des convulsions, allant de reponses minimales apres la premiere injection a des convulsions toniques apres 8 injections. La plupart des rates sans E2 de substitution n'arrivaient pas a depasser des reponses convulsives cloniques apres 22 injections. Ces resultats sont en faveur de l'influence de l'estradiol sur les processus critiques, demontree dans 2 modeles differents d'acquisition des crises. RESUMEN En ratas hembras ovariectomizadas se restituyo el estradiol (E2) mediante capsulas silasticas subcutaneas (10% E2 de coles-terol). Las ratas que tomaban E2 requirieron menos estimulaciones diarias de la aniigdala para desarrollar ataques completamente condicionados (kindled), comparando las con las ratas ovariectomizadas en las que se habian implantado capsulas de colesterol. Otras ratas fueron inyectadas con pentilenetetrazol (PTZ), 40 mg/kg i.p., cada 48 horas. Las ratas que habian to-mado E2 mostraron un incremento progresivo en la severidad convulsiva que oscilo, de minimas respuestas tras la primera in-yeccion, a convulsiones tonicas despues de 8 inyecciones. La mayor parte de las ratas sin E2 no empeoro despues de las respuestas convulsivas tras 22 inyecciones. Estos resultados indican que existe una marcada influencia del estradiol sobre los procesos convulsivos como queda demostrado en dos modelos diferentes de adquisicion de ataques.

Effect of low-level, 60-Hz electromagnetic fields on human lymphoid cells: I. Mitotic rate and chromosome breakage in human peripheral lymphocytes.

Abstract: Dividing human peripheral lymphocytes from 10 normal adults (5 males and 5 females) were exposed in vitro to low level 60-Hz electromagnetic fields for 69 hours. The current density of the electrical field was 30 microA/cm2, while the magnetic field was either 1 or 2 gauss. The cytological endpoints measured were mitotic rate and chromosome breakage. No statistically significant differences, indicative of a field effect, were observed between treated and control cells whether exposed to an electric field, a magnetic field, or to various combinations of the two.