Angiographic methods for the study of fluid mechanical factors in atherogenesis. The purpose of this thesis is to investigate the feasibility of using angiographic methods to study, in vivo, fluid mechanical phenomena believed to influence the development and localization of atherosclerotic lesions, in particular, separated flow. This involved developing a method to recognize separated flow by digital analysis of cineangiography films, testing this method both with model measurements and in a clinical material, and a detailed analysis of certain methodological problems. In addition, methods have been developed to measure the tortuosity of arteries, a phenomenon which may, according to fluid mechanical theory, promote the occurrence of separated flow. In a glass model of an arterial bifurcation, a pump generated a pulsatile flow resembling that in large arteries. Using LDV (laser Doppler velocimetry) as a reference method, three velocity profiles in the symmetry plane of the model were recorded. During diastole, extensive separated flow was demonstrated in the larger branch of the bifurcation. The flow was then cineradiographed during injection of contrast medium, and the image sequence was transferred to an image analysis workstation. Treating the image sequence as a set of time-intensity curves, time parameters representing the arrival time of the contrast agent were computed. In the resulting parametric images, zones of delayed filling were identified and found to correspond to the separated flow. Viscosity was measured for seven radiographic contrast media and, as expected, the highest values were found for the largest molecules. For iohexol and ioxaglate, which were studied in detail, a linear relation to temperature and a quadratic relation to concentration were found. Whole-blood viscosity was measured for 5 healthy volunteers at high and low shear rates, before and after mixing with contrast agents in varying proportions. At low shear, viscosity decreased, while at high shear, it increased with increasing contrast concentration. The conclusion was that modern contrast media, despite their higher viscosity, seem to affect blood rheology less than older agents. In a study of the imaging characteristics of the digitization equipment for cinefilms, the resolution proved comparable to that of an entirely digital system, while the noise level was higher. Algorithms for the correction of variations in exposure and geometric distortion are also presented. The method for analysis of cinefilms, tried in the model study, was applied, with slight modifications, to a material of 26 patients with hyperlipidemia and slight or moderate atherosclerosis.(ABSTRACT TRUNCATED AT 400 WORDS)


The usefulness of matched pair randomization for medical practice-based research. To be feasible, study designs for most intervention research in primary care settings must limit the number of participating physicians, without sacrificing the statistical power required to test the research hypotheses. A model was developed to examine sample size and statistical power requirements when using the physicians' practice as the unit of analysis. Randomized designs using either matched or unmatched samples of practices were compared under varying conditions. When baseline variability is small or the number of practice pairs is large, matching at best marginally increases power. However, in the typical case when baseline variability is large or the number of practice pairs is small, matching substantially increases the power to find intervention effects with a smaller sample. Thus, matching prior to randomization could improve the design of many intervention studies in primary care settings.


Specialty differences in primary cesarean section rates in a rural hospital. To evaluate if physician specialty is a factor in determining whether cesarean sections are performed, a retrospective review of all obstetrical records was performed at a rural hospital in northeastern Kentucky. Review of 1522 patients who delivered between January 1, 1987, and June 30, 1989, showed that staff obstetricians had a 10.8% cesarean rate compared with 8.9% for family physicians. Analysis of the diagnoses that led to cesarean delivery showed no difference between the specialties for cesarean sections performed for fetal distress, preeclampsia, or other high-risk problems, but obstetricians had an increased cesarean section rate for cephalopelvic disproportion (10.7% of all deliveries vs 6.3% for family physicians, P less than 0.001). These results suggest that physician specialty may influence cesarean section rates, although other factors could also contribute to these results.


Cesarean section rate: a comparison between family physicians and obstetricians. This retrospective study compared the cesarean section rates of family physicians and obstetricians for low-risk pregnancies. The study populations (n = 492) were demographically similar. The overall cesarean section rate for the study was 7.5%. Chi-square analysis revealed a statistically significant higher rate of cesarean section for obstetricians compared to family physicians. Obstetricians were overall three times more likely to deliver by cesarean section than were family physicians (11.3% compared to 3.8%). This pattern persisted for normal-length Stage I and Stage II labors. Equal cesarean section rates were noted in prolonged labor patterns. The rate of fetal distress, meconium, or other complications was equal between family physicians and obstetricians; equivalent fetal outcomes and Apgar scores were noted. None of the studied patient factors explained the difference in cesarean section rates between family physicians and obstetricians.


Does nurse counseling or offer of nicotine gum improve the effectiveness of physician smoking-cessation advice? Medical advice and use of nicotine gum have recently received increased attention as effective tools to encourage smokers to quit, yet the relative value of nurse vs physician counseling has not been explored in depth. In this study, 425 smokers attending three urban primary care centers in Barcelona were systematically allocated to one of three groups: group A patients received a brief counseling session to quit from their family physician; group B patients were given the same brief counseling along with a free supply of nicotine gum; group C received a brief health-education session from the primary care nurse. Three hundred forty-nine patients (82%) could be reached by telephone at the two-month follow up. By that time, after correcting for the estimated validity of the phone report of smoking status, the proportion declaring themselves to be nonsmokers was 10.9%, 11.1%, and 10.8%, respectively, without significant differences between them. At one-year follow up the proportions were 4.4%, 5.3%, and 6.0%. In the logistic regression analysis, only the expected difficulty of quitting was predictive of one-year abstention, OR = 3.1 (95% CI: 1.3-7.3). The present study shows no difference between physician versus nurse counseling and no improvement in the proportion of quitters with the addition of nicotine gum in the physician-counseled group.


An analysis of 2846 industrial illnesses and injuries seen in a family practice. We analyzed 2846 industrial illnesses and injuries in 2430 patients seen in a family practice with a large occupational medicine component over a three-and-a-half-year period. Of the 268 medical diagnoses made, back injuries and cumulative trauma disorders to the upper extremities comprised the majority. A large number of pesticide and chemical exposures were also seen. Consultations were obtained in 16.7% of the cases and 61.7% of the cases were closed as resolved. There were 17 patients hospitalized and no deaths. We recommend that family practice residents be trained in the procedures and laws of the workers' compensation system as well as in treating specific occupational health problems.


Recurrent bacterial vaginosis: association with vaginal sponge use. A hypothesis-generation study was conducted to examine risk factors for bacterial vaginosis recurrences among women participating in a randomized controlled trial of male sexual partner treatment. Of the 140 women enrolled in the trial, 72 had a normal vaginal gram-stained slide at the first follow-up visit and were included in this analysis. Nineteen of the 72 (26.2%) women developed a bacterial vaginosis recurrence documented by a vaginal gram-stained slide during the 6-week follow-up period. Of the 19 women, 4 of 6 sponge users (66%) developed a bacterial vaginosis recurrence (RR 2.93, 95% CI: 1.43-6.02). Logistic regression analysis supported the association between sponge use and bacterial vaginosis recurrences (adjusted RR 2.71, 95% CI: 1.06-6.99) but revealed that an apparent protective effect of diaphragm use was due to the confounding effect of sexual partner treatment. Our hypothesis is that bacterial vaginosis recurrences may be due to factors other than sexual transmission, such as sponge use. Further studies are needed to examine risk factors for bacterial vaginosis recurrences. In the interim, physicians might suggest another form of contraception to their sponge-using patient with frequent bacterial vaginosis infections.


Tangible assistance: a simple measure of social support predicts pregnancy outcome. The association between tangible assistance, a single-item measure of social support, and serious perinatal complications was prospectively measured in 548 rural pregnant women. Those 38 women who reported no or one reliable helper in the third trimester (low tangible assistance) had a higher rate of poor outcomes (at least one of the following: neonatal death, transfer to neonatal intensive care unit, birthweight less than 2500 g or 5-min Apgar score less than 7) than those with 2 or more helpers (13.2% vs. 5.7%, p = 0.08). All of the increase in poor outcomes occurred in women with high sociodemographic risk (at least one of the following: age less than 18, no male partner, or less than high school education). In this subgroup of 121 women, the difference in poor perinatal outcomes was striking (28.6% vs. 7.6%, p = 0.03). The association between tangible assistance and poor outcome remained after controlling for biomedical risk. A simple question about the availability of supportive companions may be clinically useful.


Perceived core procedural skills for Nebraska family physicians. We conducted a mail survey of 287 practicing family physicians, 22 family practice faculty, and 60 family practice residents in both rural and urban Nebraska concerning their perceptions of "core" procedures in family medicine and their perceived competency in performing them. Final response rate was 45%. There was general agreement concerning what constituted the core procedures in family medicine, although several newer procedures, such as flexible sigmoidoscopy, provoked more controversy. Rural physicians were more likely to classify intrauterine device insertion, endometrial biopsy, and cervical biopsy as core procedures than their urban counterparts. As expected, whether a physician performed a procedure related directly to his reported competence in performing it. However, there were discrepancies between perceived training during residency and current practice for control of nasal hemorrhage, aspiration of breast mass, flexible sigmoidoscopy, endometrial biopsy, and joint aspiration. Faculty programs for teaching procedural skills, standards for documenting competence, and systems for ongoing quality assurance should be further developed.


Cefoxitin-induced antibiotic resistance in Enterobacter species in the community hospital. The aim of this study was to determine whether beta-lactamases could be induced by cefoxitin in the community hospital, since this problem of antibiotic resistance has been shown to exist at the tertiary care level. One hundred sixty-six Enterobacter species isolated from patients in two community hospitals in Dayton, Ohio, were tested for cefoxitin induction of beta-lactamase production by a disk-approximation method. Piperacillin and cefoxitin disks were placed in approximation to each other on Mueller-Hinton plates inoculated with Enterobacter species with appropriate controls. Three Enterobacter strains (1.8%) showed truncation of the zone of inhibition (indicating beta-lactamase induction) with sensitivity to both cefoxitin and piperacillin. However, 84 strains (50.6%) showed truncation around the piperacillin disk with resistance to cefoxitin. One hundred fifty (90.0%) strains showed resistance to cefoxitin. These data indicate that cefoxitin induction of beta-lactamases in Enterobacter species is indeed a potential problem in incurring antibiotic resistance in the community hospital.


Office-based colonoscopy in a family practice. A total of 112 patients, 64 women and 48 men, underwent 157 in-office colonoscopies with intravenous sedation. A total of 113 polyps were found. Thirty polyps were of the diminutive (less than 0.6 cm) hyperplastic (metaplastic) or nonneoplastic type. Forty-three were of the diminutive adenomatous, or villous, neoplastic type, and 40 were neoplastic but larger than 0.6 cm. Biopsies and polypectomies were done. There were no instances of perforation, hemorrhage, or other major complications. A spectrum of other colorectal pathology was found, the majority of which was treated in the office. Patients were risk stratified for surveillance according to polyp histopathology, with nonneoplastic polyps assigned no risk, and neoplastic polyps assigned high risk status. This study demonstrates that for the most reliable prognostication and risk stratification, all polyps should be removed for histopathological assessment.


Influences on specialty choice of family physician graduates of a tertiary care medical school. A survey of 392 University of Michigan Medical School family physician alumni who graduated from medical school between 1950 and 1984 explored factors influencing respondent specialty choice and satisfaction with specialty choice. The strongest influences on specialty choice were the opportunity to treat a variety of illnesses, know patients personally, and work with people as opposed to things. The traditional medical school setting offered an environment of high-quality education, opportunities to see a variety of illnesses, and a model of tertiary, uncoordinated, discontinuous care that the respondents were determined not to replicate in their own medical careers. Fifty-nine percent of the respondents had no reservations about their decision to become family physicians, 74% said they would return to the University of Michigan if they were to enter medical school again, and 91% were greatly or moderately satisfied with their choice, indicating their satisfaction with their career choice and medical school.


Effects of serotonin on intracellular calcium in embryonic and adult Helisoma neurons. The neurotransmitter serotonin has been shown to regulate neurite outgrowth in many embryonic and adult Helisoma neurons. To determine whether intracellular calcium concentration is also regulated by serotonin in large numbers of neurons, the calcium indicator Fura 2 was used to measure intracellular calcium in mass-dissociated cultures of embryonic and adult neurons. Comparisons between embryonic and adult neurons revealed that embryonic neurons have a narrow population distribution of rest intracellular calcium levels around relatively low values. In contrast, the population distribution for adult neurons covered a much wider range of rest calcium concentrations. In both embryonic and adult cultures, serotonin induced a shift in the population distribution of calcium concentrations to higher levels, and increased the mean and median calcium concentrations. Analysis of individual adult neurons prior to and following the addition of serotonin revealed that approximately 50% of the neurons responded with an increase in calcium concentration. In contrast, there was no evidence of a serotonin-induced decrease in calcium concentration in any neurons. Since the percentage of neurons responding to serotonin in this study is very similar to the percentage that responded in previous studies on neurite outgrowth, these data support the hypothesis that an increase in intracellular calcium is a common intermediate step in the regulation of neurite outgrowth by serotonin throughout the Helisoma nervous system.


Modifications of synaptosomal plasma membrane protein composition in various brain regions during aging. The age-dependent modifications of synaptosomal plasma membrane protein composition in three different rat brain regions (cerebral cortex, cerebellum and striatum) at various ages (4, 12 and 24 months) were studied. The proteins were separated by gel-electrophoresis and the quantity of the different polypeptides was determined densitometrically from the stained gels. In the three brain regions examined several age-related modifications in the amount of the synaptosomal plasma membrane proteins were observed. In particular a significant decrease in the content of some synaptosomal plasma membrane proteins at 24 months of age was found. The age-related modifications in the protein composition of synaptosomal plasma membrane may cause changes in many brain functions, such as neurotransmission, ionic transport and enzyme activities. Particularly interesting is the decrease of a protein with 18 kDa mol. wt. This protein has been identified as calmodulin by immunoblotting assay. The decrease in the amount of this protein may be correlated to the impairment of several Ca(2+)-requiring processes in the aging brain.


Patterns of ethanol-induced cell death in the developing nervous system of mice; neural fold states through the time of anterior neural tube closure. Vital staining and routine histological analyses of mouse embryos 12 h after acute maternal ethanol administration (2.9 g/kg) illustrated that selected neuronal cell populations are killed. At the time of treatment, embryos had 5-15 somite pairs, corresponding to the developmental stages occurring in humans during the fourth week of post-fertilization; i.e. when neural folds are present and neural tube fusion begins. Affected cell populations in embryos having 6-26 somite pairs (up to the stage of anterior neuropore closure) were in discrete locations in the alar and basal plates of the rhombencephalon, in the otic placode/vesicle, and in the regions of the epibranchial placodes, olfactory placodes and trigeminal ganglion. The potential basis for the vulnerability of these cell populations to ethanol-induced cell death is discussed. Our understanding of the scope of ethanol-induced CNS damage is dependent upon further defining ethanol-sensitive cell populations at all stages of CNS development.


Insulin receptor in mouse neuroblastoma cell line N18TG2: binding properties and visualization with colloidal gold. Insulin function in the nervous system is still poorly understood. Possible roles as a neuromodulator and as a growth factor have been proposed (Baskin et al., 1987, Ann. Rev. Physiol. 49, 335-347). Stable cell lines may provide an appropriate experimental system for the analysis of insulin action on the various cellular components of the central nervous system. We report here a study to investigate the presence and the properties of insulin specific binding sites in the murine neuroblastoma line, N18TG2, together with insulin action on cell growth and metabolism. Also, receptor internalization has been studied. Binding experiments, carried out in standard conditions at 20 degrees C, enabled us to demonstrate that these cells bind insulin in a specific manner, thus confirming previous findings on other cell lines. Saturation curves showed the presence of two binding sites with Kd 0.3 and 9.7 nM. Competition experiments with porcine and bovine insulin showed an IC50 of 1 and 10 nM, respectively. Competition did not occur in the presence of the unrelated hormones ACTH and FSH. Dissociation experiments indicated the existence of an internalization process of the ligand-receptor complex; this was confirmed by an ultrastructural study using gold conjugated insulin. As far as the insulin action in N18TG2 cells is concerned, physiological concentrations stimulate cell proliferation, whereas no stimulation of glucose uptake was observed, indicating that insulin action in these cells is not mediated by general metabolic effects. On the basis of these data, N18TG2 line appears to be a very suitable model for further studies of the neuronal type insulin receptors, and possibly insulin specific action on the nervous system.


The extracellular matrix of cerebral gray matter: Golgi's pericellular net and Nissl's nervösen grau revisited. Glial hyaluronate-binding protein (GHAP) and a large aggregating chondroitin sulfate proteoglycan (Ag-Pg) similar to a fibroblast proteoglycan (versican) were localized in bovine, dog and cat central nervous system (CNS) gray matter by indirect immunofluorescence. The distribution of the two hyaluronate-binding proteins was identical with that of hyaluronate, an extracellular glycosaminoglycan. All substances formed a finely reticulated mesh in the neuropil with a condensation of the stain around large neurons. It is concluded that in gray matter, as in white matter, the extracellular matrix (ECM) contains hyaluronate-protein aggregates. We suggest that the hyaluronate-protein aggregates correspond to the pericellular network first described by Golgi.


Effects of pentylenetetrazol-induced seizures on dopamine and norepinephrine levels and on glucose utilization in various brain regions of the developing rat. Levels of dopamine and norepinephrine were measured in seven brain areas after 60 min of sustained seizure activity induced by intraperitoneal repetitive timed administrations of pentylenetetrazol in rats at 10, 14, 17 and 21 days of postnatal life. The tissue levels of norepinephrine were markedly reduced in the majority of brain structures, except for striatum at 10 and 14 days. Conversely, dopamine concentrations increased in many areas and at various ages, except in cerebral cortex at 10 and 14 days and in midbrain between 14 and 21 days. PTZ seizures induced marked increases over control levels in the rates of glucose utilization, measured by the quantitative autoradiographic [14C]2-deoxyglucose method, in all dopamine- and norepinephrine-innervated areas studied at 10 and 14 days, except in cerebellar cortex at both ages and in frontal cortex and anteroventral thalamus at 14 days. At 17 and 21 days, glucose utilization remained increased over control levels in some areas, mainly in catecholaminergic cell groupings such as substantia nigra, ventral tegmental area and locus coeruleus, but was significantly reduced in cortex, caudate nucleus and thalamus, and similar to control rates in other regions. The present results suggest that pentylenetetrazol-induced seizures lead to a simultaneous increase in functional activity of norepinephrine neurons and an inhibition of dopaminergic-mediated neurons. They also confirm the maturation of connections, of metabolic activity and of neurotransmitter interaction within the brain, occurring mainly during the third week of postnatal life, paralleled by an increased selective vulnerability of some regions to this kind of insult.


Culture of dorsal root ganglion neurons from aged rats: effects of acetyl-L-carnitine and NGF. In vitro neuronal preparations are used to study the action mechanism of substances which are active in normal and pathological brain aging. One major concern with in vitro assays is that the use of embryonic or adult neurons may hamper an appreciation of the relevance of these substances on aged nervous tissue. In the present study for the first time cultures of aged dorsal root ganglia from 24-months-old rats were maintained in vitro up to 2 weeks. This model was used to investigate the neurotrophic/neuroprotective action of nerve growth factor and acetyl-L-carnitine. A large population of aged dorsal root ganglia neurons was responsive to nerve growth factor (100 ng/ml). Nerve growth factor induced an increase of initial rate of axonal regeneration and influenced the survival time of these neurons. Acetyl-L-carnitine (250 microM) did not affect the axonal regeneration but substantially attenuated the rate of neuronal mortality. A significant difference was evident between the acetyl-L-carnitine-treated and the untreated neurons from the first cell counting (day 3 in culture). After 2 weeks the number of aged neurons treated with acetyl-L-carnitine was almost double that of the controls. The effects of acetyl-L-carnitine on aged DRG neurons potentially explain the positive effects in clinical and in vivo experimental studies.


Serotoninergic reinnervation of regenerating tentacular sensory organs in a pulmonate snail, Cryptomphalus aspersa. Several ontogenetic studies performed in different species suggest a developmental role for 5-HT neurons. The 5-HT system interconnecting the CNS and the tentacular sensory organs in pulmonates is a suitable model for studying the postulated developmental role of 5-HT neurons. In this paper we describe the behavior of the 5-HT fibers during the early stages of blastema reinnervation, primordium formation and differentiation of regenerating tentacular sensory organs in the pulmonate snail Cryptomphalus aspersa. Our results show that the regeneration process allows the development of a normal pattern of 5-HT innervation of the regenerated sensory organs and suggest that 5-HT could be involved in reciprocal developmental interactions with regenerating tentacular tissues.


The effective diagnosis and treatment of hypertension by the primary care physician: impact of ambulatory blood pressure monitoring. Ambulatory blood pressure monitoring (ABPM) has been described as an effective method for the diagnosis and formulation of the treatment of hypertension by the primary care physician. Sixty patients selected from a suburban private primary care practice participated in a study that compared measurements of office blood pressures using a mercury sphygmomanometer with the same pressures recorded by ABPM. Blood pressures and blood pressure loads measured by ABPM were significantly lower than blood pressures and pressure loads recorded in the office setting. Blood pressure recorded by ABPM differed from the same measurements made by office or casual sphygmomanometry. Use of ABPM changed diagnosis or treatment of hypertension in borderline and antihypertensive drug-treated patients. Ambulatory blood pressure monitoring is a useful tool for the diagnosis and treatment of hypertension by the primary care physician. It can be used to identify white-coat hypertension in various patient populations.


Factors associated with regular aerobic exercise in an elderly population. Little is known regarding the characteristics of elderly persons who do not regularly exercise. This lack of knowledge limits the design and marketing of exercise programs to persons who could benefit from regular exercise. We compared characteristics of regular exercisers and nonexercisers among 561 randomly selected persons aged 65 years and older who were enrollees of a health maintenance organization. Baseline data were obtained on sociodemographics, health attitudes, and medical conditions. Of the 561 persons studied, 192 (34 percent) were regular exercisers. Exercisers were slightly younger than nonexercisers and reported more positive health perceptions. Nonexercisers tended to report lower incomes and lower educational levels than did exercisers. Exercisers were less likely to report hypertension, arthritis, or two or more of the following medical conditions: heart disease, hypertension, arthritis, and emphysema (odds ratio 0.49; confidence interval 0.28 to 0.86). Sex differences were present. In logistic regression analysis, higher reported income, better perception of current health, and fewer than two medical conditions were associated with regular exercise status. Specific characteristics are present in persons who regularly exercise compared with those who do not. These findings may prove useful in understanding the dynamics of exercise behavior in this age group and in designing exercise interventions for this population.


Patient outcomes in hospital-based respite: a study of potential risks and benefits. Primary care physicians provide increasing care for elderly patients with chronic disabilities. To maintain these individuals in the community, families and other caregivers are supplying more intensive support in the home. Services, such as short-term respite care, can relieve the caregiver burden and allow the patient to continue community living. Whether hospital-based respite can be an effective option for patients is unclear. To determine the patient outcomes in hospital-based respite, 15 elderly male respite patients (mean age 71 years) were matched and compared during a 6-month period with 14 elderly acute care control patients and 16 community-based elderly control patients who were chronically ill and were enrolled in a hospital-based home-care program. The average respite stay was 15 days. The respite group did not experience increased risk of mortality or iatrogenesis. Benefits at 6 months included fewer admissions for acute medical care for the respite group (P less than 0.05). Total number of hospital days was equivalent for the respite group and community-based control patients and was fewer than that for the acute care group. The results do not indicate any harm and argue that a slight benefit is associated with hospital-based respite for chronically ill older adults. Because of potential complications that can develop for chronically ill geriatric patients, a hospital setting for respite can be a viable respite alternative. A valid concern for physicians, however, remains the potential danger of a greater rate of iatrogenic illness and expectation of more aggressive care based on a tertiary care model.


Intervention to increase seat belt use at a primary care center. Increasing seat belt use represents an ideal opportunity for preventive health care in family practice. Little evidence exists, however, that primary care physicians can increase safety belt use. Three hundred twenty-six patients seen in a rural primary care center were randomized to either a control or intervention group. Before their health care examination, patients completed a short questionnaire concerning seat belt use and then viewed a 6-minute videotape explaining reasons to wear seat belts (intervention) or espousing general preventive health care guidelines with no mention of seat belts (control). In 6 months the questionnaire was again administered with no further intervention. Two hundred forty-three (74.5 percent) patients completed both baseline and 6-month questionnaires. Seat belt use increased significantly from baseline to 6 months for the intervention (22 to 37.3 percent, P = 0.00052) and control (20 to 33.6 percent, P = 0.00085) groups; however, the difference between the increase in the intervention (37.3 percent) and control (33.6 percent) groups at 6 months was insignificant (P = 0.641). The most common reasons for not using seat belts were forgetfulness (40.3 percent), fear of being trapped (26.7 percent), and lack of comfort (21.8 percent). Seat belt use increased in this study, although the intervention videotape was no better than the control videotape at increasing restraint use. This increase in use supports office-based intervention to improve seat belt use, but further research is needed to clarify the mechanism and extent of change possible.


Alpha 1-antitrypsin-deficiency-related emphysema. A congenital cause of emphysema resulting from alpha 1-antitrypsin (A1AT) deficiency affects 1 in 2500 individuals and could account for emphysema in 2 percent of all persons with emphysema. Individuals aged 30 to 45 years with chronic shortness of breath and coughing could have A1AT deficiency. Using the key words "alpha 1-antitrypsin deficiency," "chronic obstructive pulmonary disease," and "emphysema," the MEDLINE files were searched from 1985 to the present. Data from articles published before 1985 were accessed from cross-reference of the recent articles. Unlike smoker's emphysema, A1AT deficiency is panacinar, appears in middle-aged patients, and is more severe at the lung bases. Chronic bronchitis, mucous hypersecretion, and liver disease, as well as a family history of emphysema, are associated conditions. Clinical management includes the avoidance of smoking and atmospheric pollution. Also available is purified, functional human A1AT in quantities large enough for intravenous replacement or augmentation therapy. Future treatment for the disease includes synthetic elastase inhibitors and an aerosolized formulation of A1AT, which is currently under investigation.


Premature labor, Part I: Risk assessment, etiologic factors, and diagnosis. This paper, the first of a two-part series on premature labor, reviews the recent literature on the causes of and risk factors for preterm labor and methods of diagnosis. A review of the literature on risk determination and diagnosis of preterm labor was conducted by searching MEDLINE files from 1983 to the present, using the key terms "preterm labor," "premature labor," "preterm labor and infection," and "uterine monitoring." Additional references were accessed by cross-referencing the bibliographies of the articles obtained through this search. Risk factors for preterm labor, which include items related to the pregnant woman's demographic characteristics, history, daily habits, and current pregnancy, have been combined into scoring systems commonly used by clinicians and researchers to single out women at risk for preterm delivery. When such systems are tested in obstetric populations, results show variable success in predicting preterm labor or birth. These inconsistent results could be due, in part, to important factors that have often been omitted from scoring systems, such as chemical abuse, poor nutrition, little social support, demanding work, multiple sexual partners, past or current sexually transmitted diseases, and other gynecologic infections. Women who are considered high risk for preterm labor can benefit from participating in preterm birth prevention programs that incorporate home monitoring, patient education regarding the signs and symptoms of preterm labor, frequent contacts with health professionals, and cervical examinations.


Improving marital relationships: strategies for the family physician. Marital conflict and divorce are prevalent in our society, and patients frequently ask family physicians to assist them with marital difficulties. These difficulties are often associated with a decline in health, resulting in additional stress to the marital unit. A MEDLINE search was undertaken using the key words "family medicine," "marital therapy," "marital counseling," "brief psychotherapy," and "short-term psychotherapy." The bibliographies of generated articles were searched for additional references. The authors used the resources of their individual behavioral science libraries, as well as their clinical experiences. With adequate training, many family physicians can include marital counseling skills in their clinical repertoires. Family life cycle theory provides a framework for understanding the common stresses of marital life and also guides the family physician in recommending strategies to improve marital satisfaction. The physician's role is twofold: (1) to identify couples in crisis, and (2) to provide preventive strategies geared to assist couples in achieving pre-crisis equilibrium or higher levels of functioning. For physicians whose practices do not include marital counseling, an understanding of the basic techniques can be beneficial in effectively referring appropriate couples for marital therapy.


First name or last name: which do patients prefer? Opinions are frequently expressed in the medical literature whether patients should be addressed by their first or last names, but few supportive data are available. Our objective was to determine the preferences of a sample of ambulatory patients to guide physicians and other professionals in addressing their patients appropriately. Three hundred seventy-five patients in a variety of ambulatory settings were asked how they wished to be addressed by physicians in various contexts. When meeting a physician for the first time, 45 percent of the respondents wanted to be called by their first names, 29 percent preferred last names, and 26 percent found either approach acceptable. When being addressed by a physician with whom they were already well acquainted, 78 percent favored given names, and only 6 percent chose surnames. Preferences varied little with age of the patient or with age or sex of the physician. These data indicate that one cannot predict reliably how a new patient will prefer to be addressed but that the great majority of established patients will want to be called by their first names.


[Angioplasty of the arteries of the aorto-iliac region]. Percutaneous transluminal angioplasty (PTA) of the aorto-iliac arteries was performed in 92 patients with atherosclerotic lesions. The initial success was 87.8% and the late one was 69.4%. The late results were evaluated objectively in 58 patients, 36 of which were studied by angiography and the remaining by Doppler. There were 6.6% of complications, in 2.8% of which surgery was performed. There was no mortality. The good initial and late results and the low morbility suggest that PTA is a good revascularization procedure. The best results were obtained in symptomatic patients with a short and significant stenosis or occlusion.


[Angioplasty of the arteries of the femoro-popliteal region]. Percutaneous transluminal angioplasty (PTA) of the femuro-popliteal arteries with atherosclerotic lesions, was performed in 66 patients. There was an initial clinical success in 80.3% and a late one in 60.7%. Better results were obtained when there was good distal circulation, and the differences were significant. There was no mortality. These results show that PTA is an useful procedure in the treatment of obstructive lesions of femuro popliteal arteries.


[Systemic granulomatous disease, of the sarcoid type, caused by inhalation of titanium dioxide. Anatomo-clinical and experimental study]. Epithelioid granulomas, sarcoid type, are reported in four workers exposed to the inhalation of titanium dioxide dust. The granulomas were observed in the lungs, associated with respiratory insufficiency leading to death, in the hilum lymph nodes and liver. Diagnosis was done after a search of the occupational background of the patients followed by chemical and histochemical identification of the inhaled dusts within the lesions (morin and chromotropic acid methods and atomic absortion spectrophotometry) and experimental production of the disease in guinea-pigs. The harmful effects of titanium are not restricted to its dioxide, or to the inhalatory route. Different types of ceramic used in human implants and prostheses and the textile and aerospace industries use titanium.


[Sarcoidosis as a cause of febrile++ syndrome of unknown origin. Retrospective study of 8 cases]. The authors report the results of a retrospective study of patients admitted to the Department of Infectious Diseases of Santa Maria Hospital with the diagnosis of sarcoidosis, from June 1982 to August 1991. Seven out of eight patients, were admitted due to fever of unknown origin. The results are discussed and the literature on sarcoidosis is also reviewed.


Intrapleural application of natural IFN alpha in breast cancer patients with pleural carcinomatosis. Monitoring of immunotherapy by assaying serum interferon levels. For resistant local recurrence, e.g. in breast cancer, or metastatic spread, local infiltration of IFN may be an interesting new approach. The aim of this study was to find out if intrapleurally administered interferon, in breast cancer patients with pleural carcinomatosis, can cause measurable serum concentrations and how soon after administration. Serum IFN concentrations were compared with those in the pleural fluid, and correlated with the presence of malignant cells in the pleural fluid. To uncover possible rhythmicity of serum interferon levels and its relationship to the timing of therapy, natural leukocyte interferon was administered intrapleurally at 10 a.m. Data on pharmacokinetics were obtained from blood samples drawn at -2, 0, 2, 8, 14, 22 and 46 h during the course of treatment. In contrast to our previous observations in healthy volunteers, levels of serum IFN before therapy had no circadian rhythmicity. Daily pharmacokinetic profile of individual patients on interferon therapy has shown that serum IFN peaks 8 h after intrapleurally administered IFN alpha. The peak depended on frequency and number of applied doses. During treatment with IFN alpha, malignant cells degenerated and finally disappeared from pleural fluid. At the same time reactive cells appeared. This effect is rather uniformly observed, but varies in degree. The number of patients is too small, however, to permit conclusions in regard to correlation of this clinical effect and the levels of serum IFN alpha.


Cerebrospinal fluid T cell receptor gamma/delta+ lymphocyte subsets in patient with AIDS-dementia complex. A subset of peripheral T cells, whose physiological function is little known, expresses a distinct CD3-associated receptor composed of gamma and delta chains. We used two monoclonal antibodies to characterize the TcR gamma/delta lymphocytes (TcR delta 1+) and their fraction (TcS delta 1+) in peripheral blood and cerebrospinal fluid of patients affected by AIDS dementia complex (ADC). Thirty patients with ADC and a control group of twenty individuals with other non-inflammatory neurological diseases (OND) were recruited. Our results demonstrate that the TcR gamma/delta cells were also present in cerebrospinal fluid of ADC patients, but we did not find any statistical difference between the two groups.


[Psychosocial impact on children with mucopolysaccharidosis]. The authors present a global valuation of the psychological repercussion of the child produced by a cronic and genetic disease like mucopolissacaridosis. The A. describe also those repercussion on the family and the school of the child. Finally they point the actual therapeutic support of the child and his family and remarks the need or pedopsychiatric management.


In vivo and in vitro macrophage activation induced by IFN gamma spontaneously released by spleen cells from tumor bearing mice. Peritoneal macrophages obtained from Lewis Lung carcinoma (3LL) tumor bearing mice release high amounts of soluble factors such as C3,H2O2 and lysosomal enzymes but fail to exert cytotoxic activity on tumor cells. In the present work we show that they acquire this property and become fully activated after in vitro incubation with supernatants derived from cultures of splenocytes from tumor bearing syngeneic mice. The presence of IFN gamma in the above supernatants was detected by immunoblotting analysis and by bioassay. The role played by IFN gamma in macrophage activation was investigated.


[Adenocarcinoma of the colon disclosed by endocarditis caused by Streptococcus bovis]. The association of Streptococcus bovis endocarditis with colonic neoplasms has been well documented. We describe a patient in whom the finding of a Str. bovis endocarditis stimulated investigation which resulted in the diagnosis and surgical treatment of an adenocarcinoma of the colon.


X-linked hypophosphatemic rickets: a study (with literature review) of linear growth response to calcitriol and phosphate therapy. Not all children with X-linked hypophosphatemia (XLH) have demonstrated improved linear growth with calcitriol [1,25-(OH)2D3] and inorganic phosphate (Pi) therapy. To assess which factors are associated with a favorable growth response during this treatment, we retrospectively compared demographics and biochemical parameters of bone metabolism to the linear growth patterns of 20 children with XLH who were prepubertal and had not required osteotomy. A total of 15 patients had family histories consistent with XLH; 5 appeared to be sporadic cases. During 3 years of therapy, the growth velocities of 12 patients had been at or above the mean for age (good growers) and those of 8 patients had been below the mean (poor growers). Data from the two groups were contrasted. We found no difference between the good growers and poor growers before or after the 3 year period of therapy in mean age, dietary calcium, calcitriol dose or compliance, or Pi dose or compliance. Both groups increased their mean fasting serum Pi levels with treatment. The TmP/GFR (mean +/- SEM) of the good growers improved with therapy (1.9 +/- 0.2 to 2.6 +/- 0.2 mg/dl, p = 0.01), and their posttreatment value was higher compared to that of the poor growers (2.6 +/- 0.1 versus 2.2 +/- 0.1 mg/dl, p = 0.02). However, their enhanced TmP/GFR was not associated with a reduction in serum iPTH levels (before, 693 +/- 50; after, 688 +/- 76 pg/ml; p = 0.9). The Z test for binomial proportions showed that the group that grew well contained a disproportionate number of girls (10 of 12, p = 0.04). Our findings suggest that calcitriol may exert a direct effect on the renal tubule to improve Pi reclamation in XLH. The observation that heterozygous girls appear to respond better than hemizygous boys to calcitriol and Pi therapy provides evidence for a gene dosage effect in the expression of this X-linked dominant disorder.


Longitudinal effect of tiludronate on bone mineral density, resonant frequency, and strength in monkeys. The effect of Tiludronate on bone was studied in 72 growing monkeys (Papio papio), 36 males and 36 females, aged 4-7 years. They were randomly allocated into four groups (18 animals per group, 9 males and 9 females): group I, controls; group II, 10 mg/kg/day; group III, 20 mg/kg/day; and group IV, 40 mg/kg/day of Tiludronate. A total of 12 animals (6 males and 6 females) in each group were sacrificed at the end of treatment (1 year) and 6 animals (3 males and 3 females) per group 1 year later. Bone mineral density (BMD) was measured by dual-photon absorptiometry. Biomechanical properties were evaluated by an impact torsion test and by resonant frequency analysis. Bone mineral measurements indicated that at the end of 1 year of treatment BMD was significantly higher, especially at the distal epiphysis of the radius, than in controls. No significant differences between groups were found in BMD 1 year after stopping treatment. Biomechanical analyses indicated that torsional stiffness increased after treatment. No differences between groups were found 1 year after stopping treatment. Results of resonant frequencies indicated an increased calculated transversal stiffness after treatment and 1 year later and an increased buckling strength 1 year after stopping treatment. In conclusion, the results on the effect of Tiludronate in growing monkeys indicate a profound effect of this drug on bone density and biomechanical properties. The biomechanical results indicate that this drug is safe, with conservation of bone strength despite a change in intrinsic mechanical properties of the bone.


Endurance training associated with slightly lowered serum estradiol levels decreases mineral density of canine skeleton. The effects of long-term running exercise were studied in 20 beagle dogs. A total of 10 dogs ran from the age of 15 weeks to the age of 70 weeks in a progressive program for up to 40 km/day. A total of 10 sister dogs spent the study period in individual cages. When the dogs were 70 weeks old, bone mineral density of the vertebrae, hip, and radius was analyzed by dual-energy x-ray absorptiometry (DEXA; Lunar) and the vertebrae were also assessed by quantitative computed tomography (QCT; Siemens DR 1). Mineral density was lower in the running dogs than in the controls. The difference was greatest in the spine in the QCT analysis. Blood chemistry analyses revealed that the metabolism of the bone was significantly accelerated. The estradiol levels showed the trend to be reduced in the running group. The beneficial effect of exercise on mineral density has been shown in many earlier studies. However, in this study we demonstrate the possibility of adverse effects of long-term exercise on bone tissue. The change was associated with a decrease of serum estradiol level.


Age-related decrements in bone mineral density in women over 65. Age-related changes in bone density contribute to the risk of fractures. To describe the relationship between age and bone mass in elderly women, we studied a large cohort of women over age 65 years who were recruited from population-based lists in four cities in the United States. Bone density in g/cm2 was measured by single-photon absorptiometry (SPA) and dual x-ray absorptiometry (DXA) at the distal and proximal radius, the calcaneus, the lumbar spine, and the proximal femur. Centralized data collection was used to control data quality and consistency. We found a strong inverse relationship between bone density and age for most sites. Decrements in bone density between women aged 65-69 years and women 85 years and older exceeded 16% in all regions except the spine, where the difference between the two age groups was 6%. Ward's triangle and the calcaneus exhibited the largest decrements, with 26 and 21%, respectively. The estimates of annual changes in bone mineral density by linear regression at sites other than the spine ranged from -0.82% at the femoral neck and trochanter to -1.30% at Ward's triangle. Correlations between the different regions ranged from r = 0.51 between the proximal radius and Ward's triangle to r = 0.66 between the distal radius and calcaneus. We conclude that the inverse relationship between age and bone mass measured by absorptiometry techniques in white women continues into the ninth decade of life. The relationship is strongest for bone density of Ward's triangle and the calcaneus and weakest for the spine.


Axial and appendicular bone density predict fractures in older women. To determine whether measurement of hip and spine bone mass by dual-energy x-ray absorptiometry (DEXA) predicts fractures in women and to compare the predictive value of DEXA with that of single-photon absorptiometry (SPA) of appendicular sites, we prospectively studied 8134 nonblack women age 65 years and older who had both DEXA and SPA measurements of bone mass. A total of 208 nonspine fractures, including 37 wrist fractures, occurred during the follow-up period, which averaged 0.7 years. The risk of fracture was inversely related to bone density at all measurement sites. After adjusting for age, the relative risks per decrease of 1 standard deviation in bone density for the occurrence of any fracture was 1.40 for measurement at the proximal femur (95% confidence interval 1.20-1.63) and 1.35 (1.15-1.58) for measurement at the spine. Results were similar for all regions of the proximal femur as well as SPA measurements at the calcaneus, distal radius, and proximal radius. None of these measurements was a significantly better predictor of fractures than the others. Furthermore, measurement of the distal radius was not a better predictor of wrist fracture (relative risk 1.64: 95% CI 1.13-2.37) than other sites, such as the lumbar spine (RR 1.56; CI 1.07-2.26), the femoral neck (RR 1.65; CI 1.12-2.41), or the calcaneus (RR 1.83; CI 1.26-2.64). We conclude that the inverse relationship between bone mass and risk of fracture in older women is similar for absorptiometric measurements made at the hip, spine, and appendicular sites.


Appendicular bone mineral and a woman's lifetime risk of hip fracture. Appendicular bone mass is inversely related to the risk of hip fracture in short-term prospective studies, but hip fractures typically occur about 30 years after menopause. We developed a model that estimates a woman's lifetime risk of hip fracture based on measurement of radial bone mass at age 50 using short-term prospective data relating bone mass to hip fracture, the correlation between bone mass at age 50 and later years, the age-specific incidence of hip fracture and mortality, and prospective data about bone mass and mortality. We estimate that a 50-year-old white woman has a 19% lifetime risk of hip fracture if her radial bone mass is at the 10th percentile for her age and an 11% lifetime risk if her bone mass is at the 90th percentile. Improved measurement techniques that have a higher predictive value for hip fracture in short-term studies could substantially increase this gradient of lifetime risk and therefore be more clinically useful.


Radial bone mineral density in pre- and perimenopausal women: a prospective study of rates and risk factors for loss. Radial bone mineral density (BMD) of 217 white women aged 22-54 years from a single rural community was evaluated in 1984 using single-photon absorptiometry. BMD was measured at a site one-third the distance from the wrist to the elbow, a site that represents predominantly cortical bone tissue. Most of these women (181; 83%) were reexamined 5 years later. The overall average 5 year radial BMD loss was -5.6%. The average rate of loss was -4.5% for women retaining positive estrogen status at follow-up (n = 108) and -7.4% for women who were in negative estrogen status at follow-up (n = 73). Baseline radial BMD measures were highly predictive of the follow-up BMD values (r = 0.80). Women with positive estrogen status and greater baseline BMD also had less BMD change. Greater baseline BMD did not predict the amount of change in women with negative estrogen status. The bone turnover markers osteocalcin and bone-specific alkaline phosphatase were significantly associated with BMD change in women with negative, but not positive estrogen status. There was no conclusive evidence of a "peak age" in the baseline and follow-up BMD measures. Based on rates of BMD change, "peak" bone mineral content appears to occur before age 25 years. Factors significantly associated with lower levels of BMD were menopause without estrogen replacement, nulliparity, smoking, and age at first pregnancy. Factors associated with more bone loss were menopause without estrogen replacement, smoking, shorter duration of oral contraceptive use, and older age. Quetelet index, muscle area, number of lost pregnancies, ever breast-feeding, or calcium intake were not associated with BMD level or its 5 year rate of loss. Physical activity and alcohol intake were not associated with BMD level or change after data were adjusted for age or estrogen status.


Influence of oophorectomy on serum levels of sex steroids and bone metabolism and assessment of bone mineral density in lumbar trabecular bone by QCT-C value. The present cross-sectional study was carried out to determine the influence of oophorectomy (OPX) on serum levels of sex steroids and bone metabolism, as well as bone mineral density (BMD), in OPX subjects in comparison with age- and body size-matched controls. Quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) demonstrated a remarkable reduction in BMD in OPX subjects. In particular, the QCT of the centrum of vertebral bone (QCT-C) in these subjects was no more than 69.33 +/- 3.40% (X +/- SEM) of the control value, and this parameter was much lower than the QCT integral (QCT-I) value of total lumbar vertebrae. This means that BMD decreases specifically in spongy portions after OPX. The serum level of estrone (E1) was significantly lower in OPX subjects than in controls. The hormonal action of E1 on target organs has been thought to be only one-third of that of estradiol (E2), but the marked reduction in serum E1 level seemed to be a significant cause of the reduction in BMD. The serum level of androstenedione (delta 4) significantly decreased in OPX subjects and appeared to affect bone metabolism negatively. Both bone formation and bone resorption were found to be stimulated following OPX, but the rate of bone resorption was found to be higher than that of bone formation: there was an imbalance between bone formation and bone resorption in OPX subjects. However, it was not possible to prove a relationship between Ca regulating hormone and this phenomenon. In conclusion, the QCT-C value reflects the changes in spongy vertebral BMD more sensitively than the QCT-I value or DPA.(ABSTRACT TRUNCATED AT 250 WORDS)


Activation and inhibition of protein kinase C in cultured bovine parathyroid cells: effect on the release of C-terminal fragments of parathyroid hormone. The response of the parathyroid gland to low Ca2+ may be mediated in part by protein kinase C (PKC). We assessed the effect of two PKC activators, SC-9 and SC-10, and one PKC inhibitor, H-7, on Ca(2+)-regulated PTH release and degradation in primary cultures of bovine parathyroid cells. Both SC-9 and SC-10 stimulated PTH release, compared to high Ca2+ alone, in parathyroid cells incubated in high Ca2+, with maximal PTH release of at least twofold occurring at a concentration of either activator of 10 nM (p less than 0.05). We have previously shown that another PKC activator, PMA, not only enhances PTH release in the presence of high Ca2+ but suppresses low Ca(2+)-stimulated PTH secretion. In the present study, neither SC-9 nor SC-10 caused a comparable suppression of PTH release at low Ca2+. However, the PKC inhibitor, H-7 (1 microM), blocked low Ca(2+)-stimulated (compared to the low Ca2+ control) PTH secretion by approximately 50% (p less than 0.01) and did not affect high Ca2+ suppression of PTH secretion. H-7 (1 microM) was able to oppose the stimulation of PTH release by the PKC activators SC-9, SC-10, and PMA at high Ca2+ and negated the PTH release-inhibiting effect of PMA at low Ca2+. Culture medium from these experiments was subjected to reversed-phase HPLC and the eluted fractions analyzed by RIA for the presence of intact and C-terminal fragments of PTH.(ABSTRACT TRUNCATED AT 250 WORDS)


Adaptive regulation of ascorbate transport in osteoblastic cells. Osteoblasts possess a concentrative L-ascorbate (vitamin C) uptake mechanism involving a Na(+)-dependent ascorbate transporter located in the plasma membrane. The transporter is specific for ascorbate and stereoselective for L-ascorbate over D-isoascorbate. The present study examined the effects of ascorbate supplementation and deprivation on the activity of this transport system. L-ascorbate transport activity was determined by measuring uptake of the vitamin by ROS 17/2.8 osteosarcoma cells during 1 minute incubations with 5 microM L-[14C]ascorbate. The initial rate of L-[14C]ascorbate uptake by ROS 17/2.8 cells grown for 18 h in L-ascorbate-replete medium was 89 +/- 8 nmol/g protein per minute. Following removal of L-ascorbate from the growth medium, the initial rate of uptake increased within 6 h to 126 +/- 13 nmol/g protein per minute. Conversely, the initial rate of uptake by cells grown in ascorbate-free medium decreased following the addition of L-ascorbate, but not D-isoascorbate, to the medium. The effect of ascorbate pretreatment was specific for ascorbate transport in that preincubation of cultures with L-ascorbate did not affect uptake of 2-deoxy-D-glucose. Kinetic analysis revealed that modulation of ascorbate transport arose from changes in the apparent maximum rate of transport (Vmax) without changes in the affinity of the transport system for L-ascorbate. These experiments are the first to show that ascorbate transport by osteoblastic cells responds to vitamin C deprivation and supplementation. Adaptation of transport activity to substrate availability may play an important role in the physiological regulation of intracellular ascorbate levels.


Distinct proliferative and differentiated stages of murine MC3T3-E1 cells in culture: an in vitro model of osteoblast development. We examine clonal murine calvarial MC3T3-E1 cells to determine if they exhibit a developmental sequence similar to osteoblasts in bone tissue, namely, proliferation of undifferentiated osteoblast precursors followed by postmitotic expression of differentiated osteoblast phenotype. During the initial phase of developmental (days 1-9 of culture), MC3T3-E1 cells actively replicate, as evidenced by the high rates of DNA synthesis and progressive increase in cell number, but maintain a fusiform appearance, fail to express alkaline phosphatase, and do not accumulate mineralized extracellular collagenous matrix, consistent with immature osteoblasts. By day 9 the cultures display cuboidal morphology, attain confluence, and undergo growth arrest. Downregulation of replication is associated with expression of osteoblast functions, including production of alkaline phosphatase, processing of procollagens to collagens, and incremental deposition of a collagenous extracellular matrix. Mineralization of extracellular matrix, which begins approximately 16 days after culture, marks the final phase of osteoblast phenotypic development. Expression of alkaline phosphatase and mineralization is time but not density dependent. Type I collagen synthesis and collagen accumulation are uncoupled in the developing osteoblast. Although collagen synthesis and message expression peaks at day 3 in immature cells, extracellular matrix accumulation is minimal. Instead, matrix accumulates maximally after 7 days of culture as collagen biosynthesis is diminishing. Thus, extracellular matrix formation is a function of mature osteoblasts. Ascorbate and beta-glycerol phosphate are both essential for the expression of osteoblast phenotype as assessed by alkaline phosphatase and mineralization of extracellular matrix. Ascorbate does not stimulate type I collagen gene expression in MC3T3-E1 cells, but it is absolutely required for deposition of collagen in the extracellular matrix. Ascorbate also induces alkaline phosphatase activity in mature cells but not in immature cells. beta-glycerol phosphate displays synergistic actions with ascorbate to further stimulate collagen accumulation and alkaline phosphatase activity in postmitotic, differentiated osteoblast-like cells. Mineralization of mature cultures requires the presence of beta-glycerol phosphate. Thus, MC3T3-E1 cells display a time-dependent and sequential expression of osteoblast characteristics analogous to in vivo bone formation. The developmental sequence associated with MC3T3-E1 differentiation should provide a useful model to study the signals that mediate the switch between proliferation and differentiation in bone cells, as well as provide a renewable culture system to examine the molecular mechanism of osteoblast maturation and the formation of bone-like extracellular matrix.


Isolation and characterization of a cDNA for osteopontin-k: a kidney cell adhesion molecule with high homology to osteopontins. Screening of a bovine renal cDNA library with MAbs resulted in the isolation of a 1447 bp cDNA. This cDNA (pBk2.1) was sequenced and shown to contain an open reading frame with a putative protein of 261 amino acids, with a molecular weight of 29,573 (minute leader sequence) and a hydrophobic leader sequence of 16 amino acids. pBk2.1 was shown to share a high level of nucleic acid sequence homology over portions of its sequence to human, porcine, mouse, and rat osteopontins (40-60%). The peptide (osteopontin-k) had a potential glycosylation site (Asn-X-Ser/Thr), a GRGDS receptor binding region, a high level of asparagine residues, and a high abundance of acid amino acids characteristic of osteopontin-like cell adhesion molecules. The N-terminal amino acid region of pBk2.1 (the first 82 amino acids) and 42 amino acids at the C terminus had the highest level of homology with the osteopontins at 86%. The middle portion of the peptide had greatly reduced homology, ranging from 50% (amino acids 83-174) to 12% (amino acids 175-219). There were also deletions and additions of sequence in osteopontin-k that were not found in the other osteopontins. The homologies suggest that these proteins are highly related and may be derived from a common gene by alternative splicing. A 678 bp cRNA probe constructed from pBk2.1, containing a region with low homology to the osteopontins (amino acids 183-219 with less than 20% homology, plus amino acids 220-261 and untranslated sequence), was used in northern blots and RNAse protection assays.(ABSTRACT TRUNCATED AT 250 WORDS)


Perspective. How many women have osteoporosis? Osteoporosis is widely viewed as a major public health concern, but the exact magnitude of the problem is uncertain and likely to depend on how the condition is defined. Noninvasive bone mineral measurements can be used to define a state of heightened fracture risk (osteopenia), or the ultimate clinical manifestation of fracture can be assessed (established osteoporosis). If bone mineral measurements more than 2 standard deviations below the mean of young normal women represent osteopenia, then 45% of white women aged 50 years and over have the condition at one or more sites in the hip, spine, or forearm on the basis of population-based data from Rochester, Minnesota. A smaller proportion is affected at each specific skeletal site: 32% have bone mineral values this low in the lumbar spine, 29% in either of two regions in the proximal femur, and 26% in the midradius. Although this overall estimate is substantial, some other serious chronic diseases are almost as common. More importantly, low bone mass is associated with adverse health outcomes, especially fractures. The lifetime risk of any fracture of the hip, spine, or distal forearm is almost 40% in white women and 13% in white men from age 50 years onward. If the enormous costs associated with these fractures are to be reduced, increased attention must be given to the design and implementation of control programs directed at this major health problem.


Chronic adaptation of dog parathyroid function to a low-calcium-high-sodium-vitamin D-deficient diet. The development of secondary hyperparathyroidism was studied in relation to changes in serum ionized Ca (Ca2+), 25-OHD, and 1,25-(OH)2D concentrations in six dogs maintained on a low-Ca (0.05%), high-Na (1.6%), and vitamin D-deficient diet for 91 weeks. Blood samples and evaluations of the parathyroid function were obtained before and after 3, 12, 24, 36, and 91 weeks of diet. Serum iPTH was measured by an intact hormone (I) and a carboxy-terminal (C) assay. The sigmoidal relationship between ionized Ca and iPTH values was evaluated mathematically. Results are means +/- SD. Statistically significant changes over a time period were evaluated by an ANOVA for repeated measurements. Over the first 3 weeks, serum Ca2+, 25-OHD, and 1,25-(OH)2D did not change but stimulated I-iPTH increased 84.3 +/- 39.9% (p less than 0.005) and C-iPTH only 25.3 +/- 12.2% (p less than 0.01), a significant difference (p less than 0.02). The increase in stimulated I-iPTH reached 487.4 +/- 139.6% (p less than 0.0001) and 418.4 +/- 76.9% (p less than 0.0001) for C-iPTH by the end of the study. Similar significant increases were seen in basal and nonsuppressible iPTH at or after week 12.(ABSTRACT TRUNCATED AT 250 WORDS)


The calcium oxalate crystal growth inhibitor protein produced by mouse kidney cortical cells in culture is osteopontin. Urine contains proteins that inhibit the growth of calcium oxalate (CaOx) crystals and may prevent the formation of kidney stones. We have identified a potent crystal growth inhibitor in the conditioned media from primary cultures of mouse kidney cortical cells. Conditioned media, incubated with the kidney cells for 6-72 h, was assayed for crystal growth inhibition; inhibitory activity increased 15-fold by 24 h. Inhibitory activity was purified from serum-free media containing proteinase inhibitors using anion-exchange and gel-filtration chromatography. A single band of molecular weight 80,000 daltons was seen after SDS-polyacrylamide gel electrophoresis. The sequence of the N-terminal 21 amino acids of this protein matched that of osteopontin (OP), a phosphoprotein initially isolated from bone matrix. Antisera raised to fusion proteins produced by plasmids containing the N-terminal or C-terminal portions of OP cDNA also cross-reacted with the protein purified from cell culture media on western blots. The effect of the purified protein on the growth of CaOx crystals was measured using a constant composition assay. A 50% inhibition of growth occurred at a protein concentration of 0.85 micrograms/ml, and the dissociation constant of the protein with respect to CaOx crystal was 3.7 x 10(-8) M. The concentration of OP in mouse urine, measured using antibodies raised to the purified protein, was approximately 8 micrograms/ml. We conclude that OP is synthesized by kidney cortical tubule cells and functions as a crystal growth inhibitory protein in urine.


Is heritability a risk factor for postmenopausal osteoporosis? We investigated heritability as a risk factor for the development of osteoporosis in two randomly selected populations of postmenopausal women and their premenopausal daughters. We determined the familial resemblance in bone mass at three sites; the distal forearm, lumbar spine, and proximal femur, premenopausally and with increasing maternal postmenopausal age. We also examined the bone mass of daughters in relation to mothers with and without osteoporotic fractures. Peak bone mass among premenopausal siblings was significantly correlated at all sites (r = 0.30-0.42, p less than 0.001). The same levels of resemblance were found between early postmenopausal mothers and premenopausal daughters. There was no significant difference in bone mass at any skeletal site between daughters of women with either peripheral or spinal fractures and daughters of women without fractures. We also examined familial resemblance with four biochemical markers of bone turnover (fasting urinary calcium and hydroxyproline, both corrected for creatinine, serum alkaline phosphatase, and plasma bone Gla protein). A generally significant resemblance were seen in premenopausal siblings (r = 0.25-0.39, hydroxyproline NS), but not between premenopausal daughters and postmenopausal mothers. We conclude that peak bone mass is hereditary in the distal forearm, lumbar spine, and proximal femur, but the mother-daughter resemblance explains only about 16% of the variability in daughters' bone mass. Furthermore, daughters of women with a moderate state of osteoporotic fractures are not substantially at an increased risk of having a low peak bone mass compared to the daughters of women without fractures.


Genetic expression of extracellular matrix proteins correlates with histologic changes during fracture repair. We characterized gene expression in the reparative callus that formed after fracture of the rat femur. The callus was divided into regions of bone formation (hard callus) and cartilage formation (soft callus), and gene expression was examined separately in each region. Expression of extracellular matrix protein genes varied with the progression of repair and differed between hard and soft calluses. Messenger ribonucleic acids (mRNAs) for osteonectin, alkaline phosphatase, and type I procollagen were detected in the hard callus at maximal levels during endochondral ossification and bone remodeling (day 15) and at 50% maximal levels during intramembranous bone formation (day 7). Messenger RNAs for these proteins in the soft callus were detected at low levels during chondrogenesis (day 9) but increased to 80% of maximal levels with chondrocyte hypertrophy and mineralization of the cartilage matrix (day 13). Messenger RNAs for type II procollagen and proteoglycan core protein were detected at maximal levels in the soft callus during chondrogenesis (day 9). Osteocalcin gene expression was detected in the hard callus during endochondral ossification and remodeling but not during intramembranous bone formation or at any time in the soft callus. Osteonectin mRNA was detected in both the hard and soft callus throughout the entire course of fracture repair. Expression of cartilage and bone-related genes correlated with the temporal sequence of histologic changes, suggesting transcriptional regulation of gene expression during repair. Differences in gene expression between hard and soft callus and in each of these regions as repair progressed suggest local regulation of gene expression during cell differentiation and matrix synthesis.


Responsiveness to 1,25-dihydroxyvitamin D3 is reduced in lymphocytes from osteoporotic women. The purpose of this work was to test the hypothesis that reduced responsiveness of target organs to 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] is associated with osteoporosis. Peripheral blood mononuclear (PBM) cells have been previously shown to be a valid model for the action of 1,25(OH)2D3 on its classic target organs in various pathologic and physiologic situations. The responsiveness of lymphocytes to the hormone can be assessed by the extent of inhibition it exerts on the proliferative response to mitogenic lectins. A group of 39 postmenopausal women, at least 10 years after the menopause, participated in the study. Osteoporosis, defined as the presence of at least one nontraumatic vertebral crush fracture, was diagnosed in 19 subjects. Mitogenesis of PBM cells stimulated by phytohemagglutinin and cultured for 72 h in the presence or absence of 1,25-(OH)2D3 (0.03-1 nmol/liter) was assessed by [3H]thymidine incorporation during a 4 h pulse. The maximal inhibitory effect of 1,25-(OH)2D3 at saturating concentration (1 nM/liter) was 74.6 +/- 2.8% (mean +/- SEM) for normal compared to 65.3 +/- 2.9% for osteoporotic women (P = 0.015). The geometric mean of the ED50 values of 1,25-(OH)2D3 was 60% higher in the osteoporotic than in the normal group (P = 0.035). Our data are consistent with the notion that reduced responsiveness of target organs to 1,25-(OH)2D3 is associated with osteoporosis.


Site-matched calcaneal measurements of broad-band ultrasound attenuation and single X-ray absorptiometry: do they measure different skeletal properties? Because of the differences in the interactions of ultrasound and x-ray waves with bone, quantitative ultrasound (QUS) techniques may yield information about skeletal status not accessible by regular bone densitometry (BD) techniques. However, relatively strong correlations have been reported between broad-band ultrasound attenuation (BUA) and several x-ray-based BD methods. We assessed the precision and association of single x-ray absorptiometry (SXA) and BUA of the calcaneus. We examined both BUA and SXA at the calcaneus using special software for matching the regions of interest. An algorithm was derived and applied to correct the observed correlation coefficients for the attenuation effect caused by the precision errors for BUA and SXA. In a group of 33 volunteers covering a wide range of age and calcaneal bone mineral densities, the site-matched and precision-adjusted correlation coefficient between BUA and SXA was r = 0.58, with a standard error of the estimate (SEE) of 14.41 dB/MHz, or 17.08%. For the subgroup of 25 women the correlation was stronger, with r = 0.72 and SEE = 11.53 dB/MHz, or 14.33%. SXA precision was 0.79% for the regular region of interest (ROI) and 1.22% for the site-matched ROI. BUA precision was 2.76% for the entire subject group and 1.63% for women of age 40 or older. The observed correlation coefficient between ultrasound and x-ray based techniques of the order of 0.7 is significant, but it leaves about 50% of the variability unexplained.(ABSTRACT TRUNCATED AT 250 WORDS)


Assessment of spinal and femoral bone density by dual X-ray absorptiometry: comparison of lunar and hologic instruments. Clinical application of techniques for assessing bone mineral density (BMD) requires accurate and precise measurements that can be related to clearly defined normal ranges. In this study we investigated the clinical interpretation of BMD values in a group of individuals measured on the same day with two different dual-energy x-ray densitometers (Lunar DPX and Hologic QDR 1000). The BMD results were analyzed as absolute values in g/cm2 and with respect to young and age-specific normals as defined by each manufacturer. Absolute BMD values measured by the two instruments were highly correlated (lumbar spine r = 0.98, femoral neck r = 0.95; p less than 0.0001). In the lumbar spine, the two instruments assigned almost identical values when expressed as a percentage of age-matched values and as a percentage of young normals, despite a small but systematic difference between the values assigned for the latter index. In the femoral neck, however, there were significant differences in assignments between instruments, expressed both as a percentage of young normal (mean difference 6.2%) and with respect to age-matched values (mean difference 3.3%). In particular, in premenopausal subjects femoral neck values with the Hologic instrument were assigned significantly lower values. This study shows effective comparability between these two instruments for absolute and relative values for the lumbar spine, as well as for absolute values at the femoral neck, but important differences for normality assignments at the femoral neck. These latter differences may produce bias in the "diagnosis" of femoral neck osteoporosis and may have important implications for clinical decision making.(ABSTRACT TRUNCATED AT 250 WORDS)


Effects of deflazacort on aspects of bone formation in cultures of intact calvariae and osteoblast-enriched cells. Deflazacort, a synthetic glucocorticoid reported to have bone-sparing properties in vivo, and cortisol were compared for their effects on bone formation in vitro. Deflazacort and cortisol were studied for their effects on DNA and collagen synthesis in cultures of intact fetal rat calvariae and of osteoblast-enriched (Ob) cells from 21- to 22-day-old fetal rat parietal bone. Both steroids were also examined for their effects on skeletal insulin-like growth factor (IGF) I production, which is decreased by cortisol and appears relevant to its mode of action. After 24 h of culture, deflazacort and cortisol had limited effects on the parameters studied, although cortisol at 100 nM decreased [3H]proline incorporation into collagen in intact calvariae. In contrast, after 72 h deflazacort and cortisol at 1-100 nM inhibited the incorporation of [3H]thymidine into DNA and at 100 nM decreased the incorporation of [3H]proline into collagen and noncollagen protein in intact calvariae. Deflazacort and cortisol at 10-1000 nM decreased calvarial collagen degradation to a similar extent. Both steroids had a similar activity, and at 100 nM for 72 h they decreased IGF-I production by calvariae; however, cortisol at 10 nM was somewhat more effective than deflazacort in decreasing IGF-I levels. Deflazacort and cortisol had analogous effects in Ob cell cultures. After 24 h of treatment, deflazacort at 100-1000 nM and cortisol at 10-1000 nM decreased the labeling of DNA, and both steroids at 100-1000 nM caused a similar decrease in [3H]proline incorporation into collagen in Ob cells.(ABSTRACT TRUNCATED AT 250 WORDS)


Restoring and maintaining bone in osteopenic female rat skeleton: I. Changes in bone mass and structure. This experiment contains the crucial data for the lose, restore, and maintain (LRM) concept, a practical approach for reversing existing osteoporosis. The LRM concept uses anabolic agents to restore bone mass and architecture (+ phase) and then switches to an agent with the established ability to maintain bone mass, to keep the new bone (+/- phase). The purpose of this study was to learn whether switching to an agent known chiefly for its ability to maintain existing bone mass preserves new bone induced by PGE2 in osteopenic, estrogen-depleted rats. The current study had three phases, the bone loss (-), restore (+), and maintain (+/-) phases. We ovariectomized (OX) or sham ovariectomized (sham-OX) 5.5-month-old female rats (- phase). The OX rats were treated 5 months postovariectomy with 1-6 mg PGE2 per kg/day for 75 days to restore lost cancellous bone mass (+ phase), and then PGE2 treatment was stopped and treatment began with 1 or 5 micrograms/kg of risedronate, a bisphosphonate, twice a week for 60 days (+/- phase). During the loss (-) phase, the cancellous bone volume of the proximal tibial metaphysis in the OX rat fell to 19% of initial and 30% of age-matched control levels. During the restore (+) phase, the cancellous bone volume in OX rats doubled. When PGE2 treatment was stopped, however, and no special maintenance efforts were made during the maintain (+/-) phase, the PGE2-induced cancellous bone disappeared. In contrast, the PGE2-induced cancellous bone persisted when the PGE2 treatment was followed by either a 1 or 5 micrograms treatment of risedronate per kg given twice a week for 60 days during the maintain (+/-) phase. The tibial shaft demonstrated very little cortical bone loss during the loss (-) phase in OX rats. The tibial shaft cortical bone fell some 8%. During the restore (+) phase, new cortical bone in OX rats increased by 22%. When PGE2 treatment was stopped and nothing was given during the maintain (+/-) phase, however, all but the PGE2-induced subperiosteal bone disappeared. In contrast, when PGE2 treatment was stopped and 1 micron risedronate per kg twice a week for 60 days was administered during the maintenance (+/-) phase, the PGE2-induced subperiosteal bone and some of the subendocortical bone and marrow trabeculae persisted.(ABSTRACT TRUNCATED AT 400 WORDS)


Demonstration of sodium/calcium exchange in rodent osteoblasts. Based on the inhibition of stimulated Ca release from cultured bone by several different agents that alter Na transport, we proposed that hormonally stimulated bone resorption requires Na/Ca exchange. Calcemic hormones appear to interact primarily directly with the osteoblast, which then mediates the activation of osteoclast activity. In organ culture it is not possible to determine whether Na/Ca exchange is involved in this initiating step in the osteoblast or directly in osteoclast-mediated Ca release, and there have been no prior direct measurements of Na/Ca exchange in bone or bone cells. The purpose of this study was to demonstrate the presence of Na/Ca exchange transport in the osteoblast. Thus, we characterized Na-dependent Ca transport in osteoblast-like rat osteosarcoma cells (UMR-106) and primary bone cells isolated from neonatal mouse calvaria. Cells were loaded with the Ca-sensitive dye fura-2 in the presence of physiologic NaCl and the absence of Ca with or without 0.3 mM ouabain. Changes in free cytosolic Ca after the extracellular addition of 1.5 mM Ca were measured spectrofluorimetrically. An outward Na gradient was generated by decreasing extracellular Na while maintaining isotonicity. UMR-106 cells that were Na loaded by ouabain inhibition of Na,K-ATPase activity exhibited 30% greater Ca uptake than control cells. Similar results were obtained with primary bone cells. This uptake required extracellular Ca, was not inhibited by 200 microM verapamil, and was reversible upon reversal of the Na gradient. These data demonstrate the presence of a Na/Ca exchange transport system in osteoblasts.


Hypocalcemic actions of amylin amide in humans. Amylin (also known as islet amyloid polypeptide and diabetes-associated peptide) has recently been shown by us to have a potent hypocalcemic effect in rat and rabbit owing to inhibition of osteoclast-mediated bone resorption. The hypocalcemic potency of amylin was found to be second only to that of calcitonin (CT) and is 100-fold more potent than calcitonin gene-related peptide. Here we demonstrate that amylin has a hypocalcemic effect in patients with Paget's disease of bone. Both human CT (hCT) and amylin induced a maximum hypocalcemic effect 2 h following intravenous administration of the peptides (p less than 0.001). Although on a molar basis amylin is less potent than CT, it exhibits a significantly prolonged hypocalcemic effect compared to hCT. Here we demonstrate for the first time a profound hypocalcemic effect of amylin in the human, despite sharing only 15% amino acid sequence identity with hCT.


Ultrastructure of the ventral lateral geniculate nucleus (LGNv) receiving tectal afferents in the cat. The ultrastructure of the ventral lateral geniculate nucleus (LGNv) associated with the superior colliculus was investigated. In addition to normal synaptic morphology tectal input was examined following unilateral ablation of the superior colliculus at survival times of 2 to 12 days. Eight cats were used (six experimental, two control). Examination of the ventromedial LGNv revealed a prevalence of Flat-Symmetric (FS) synapses (58.2 +/- 1.9%), relative to the usually more abundant, Round-Asymmetric (RA) contacts (41.8 +/- 1.8%). The functional morphology of terminating tectal fibres (although infrequent) was suggestive of the FS type. Since FS connections usually serve an inhibitory purpose, it is suggested that the tectal LGNv connection has a negative modulation function in the fixation and tracking process.


Catecholamines and DOPAC in cortical and neostriatal regions during rats' learning of delayed alternation. Dopamine, norepinephrine and DOPAC were measured in two cortical areas (the medial prefrontal and the posterolateral, Te2) and in the anterior and posterior neostriatum in rats which were exposed to three different experiences for three different lengths of time. One group learned delayed alternation and the two others served as controls. Throughout the training period all animals were housed in single cages. There was no significant effect of the kind of experience on any measure, but the length of exposure did affect some values: the amount of non-precursor dopamine was decreased significantly in both neostriatal samples. A significant increase of dopamine turnover and amount of norepinephrine was found in the Te2 area and in the posterior neostriatal sample. The observed changes are attributed to isolation stress. We conclude that although, as it has been described earlier, dopamine transmission is necessary for mediation of behavioural functions of the prefrontal system, it does not change quantitatively in the system during specific activity.


Chlorpromazine exerts stronger suppressive action on the instrumental responses motivated by social than by alimentary reward. Experiments were performed on six dogs over-trained before treatment, in differentiation of two instrumental responses, i.e. reinforced either by food or by sensory-social reward (petting by the experimenter). Chlorpromazine was injected intramuscularly (1.5 mg/kg) in two separate series. In the first series the drug was given four times during two weeks (twice a week). In the second series, it was injected every day for four consecutive days. Chlorpromazine produced a decrease of performance and an increase of response latencies and errors but this effect was much more evident with social than with alimentary reward. The effect of the drug was similar in both variants of the experiment, although it was more pronounced in the second than in the first series. Food intake was not changed. The motor and autonomic disturbances produced by the drug were not correlated with the decrease in instrumental performance. It is suggested that chlorpromazine acts rather on motivational or rewarding processes than on hunger drive or instrumental performance as such.


5-HT1 receptors in the structures of visual pathway of normal and monocularly deprived kittens. The density and pattern of distribution of 5-HT1 receptor sites was examined using quantitative in vitro autoradiography with [3H]5-HT as a ligand in the visual structures of 5 weeks old kittens. One group of animals had normal binocular vision, the other was monocularly deprived during the last three days of life. The density of 5-HT1 receptor sites and the pattern of their distribution in the visual structures showed distinct regional, areal and laminar differences. In the primary visual cortex (area 17) a high labelling density was found as compared with other cortical areas investigated. Three bands of high binding density were observed corresponding to cortical layers II-III, IV c and VI. This pattern distinguished area 17 from other cortical areas investigated. In subcortical visual structures very high labelling was present in the superficial visual layers of superior colliculus, but LGN showed rather weak labelling although the lamination of LGN was also seen in the pattern of distribution of 5-HT1 sites. Neither density nor pattern of 5-HT1 sites in the visual cortex and superior colliculus were affected by 3 days of monocular deprivation. High density of labelling and the distinct pattern of 5-HT1 receptor sites in the primary visual cortex suggest the important role of serotonergic transmission in the modulation of visual afferent input activity.


Glycine enhances extracellular 45Ca2+ response to NMDA application investigated with microdialysis of rabbit hippocampus in vivo. This study evaluates the role of glycine in in vivo modulation of the activity of excitatory amino acid receptors sensitive to N-methyl-D-aspartate (NMDA) in the rabbit hippocampus. Changes of extracellular calcium concentration were studied by the microdialysis technique combined with 45Ca-utilizing clearance method. The steady state level of amino acids in the dialysate was analyzed with HPLC. Pharmacologically active substances were applied directly to the hippocampus via the dialysis medium. Glycine concentration in the extracellular fluid of the hippocampus was in the range of 10(-5) M. Application of NMDA induced a drop of calcium concentration in the extracellular compartment of the hippocampus. This effect was inhibited by 7-Cl-kynurenic acid, an antagonist of glycine binding site on the NMDA receptors. Application of glycine and D-serine to the dialysis medium did not interfere with the basal level of extracellular calcium in the hippocampus, but resulted in an enhancement of the NMDA-induced decrease of calcium concentration. These results indicate that in the hippocampus the NMDA receptors are under constant positive modulation by endogenous glycine. Since glycine binding sites on the NMDA receptors are not saturated by an endogenous ligand, glycine may play a role in regulation of the NMDA receptor activity in the hippocampus in vivo.


Modulation of GABA transport in synaptosomes by histamine. We have examined the effects of exogenous and intrasynaptosomal histamine on the GABA transport in rat brain synaptosomes. Exogenous histamine had no effect on GABA uptake, but inhibited veratridine-evoked GABA release. GABA uptake was susceptible to the modification of histamine synthesis in synaptosomes. The increase of synaptosomal histamine level by incubation under conditions favouring histamine synthesis from 2.6 to 5.2 pmole/mg protein, decreased the GABA uptake by about 75%. As demonstrated in experiments with an inhibitor of histidine decarboxylase--semicarbazide, this effect comprised 15% inhibition evoked by the histamine precursor--histidine, whereas the remaining 60% inhibition could be ascribed to the effect of newly synthesized histamine.


Motor units of medial gastrocnemius muscle in the rat during the fatigue test. II. Changes in the time course of sequential tetani of fatigue test. Seventy motor units (MUs) of 3 types: fast fatigable (FF), fast resistant to fatigue (FR) and slow (S) were studied in medial gastrocnemius muscle of the rat. The fatigue test time course showed significant variability. It was found, that slow MUs, apart from greater resistance to fatigue, had less variable tetanic time course during the fatigue test than the fast MUs. The tetani of fast MUs were unfused with a marked sag. At the beginning of fatigue test the tension of fast motor units increased. The increase appeared to be greater and more rapidly developing in FF than in FR MUs. In the next part of fatigue test, when decrease in the tetanic tension was observed, the tetanic time course was changing in FF but not in FR MUs. During the first tetanus of fast MUs the sag exhibited a significant variability of its time course. In a proportion of fast MUs the sag appeared again when their tension was potentiated but in such a case it showed a different time course. The obtained results point to high degree of specialization of MUs in the studied muscle.


Grading of supratentorial arteriovenous malformations on the basis of multivariate analysis of prognostic factors. The case histories and angiograms of 93 consecutive patients who underwent surgery for arteriovenous malformations were analyzed retrospectively to find clinical and radiological prognostic factors influencing the outcome. A stepwise multiple regression was performed as follows. All radiological data such as size, location, and feeding and draining vessels as well as the clinical data such as age, sex, clinical grade on admission were introduced into the model and tested whether they contributed significantly to the prediction of the outcome which was the target variable. If so they were retained, otherwise eliminated. By this procedure the following features were identified as significant prognostic factors which adversely influence the outcome: poor clinical grade, feeding vessels from the A 1-segment and the anterior communicating artery, feeders from the M 1-segment, feeders from the Rolandic branches of the middle cerebral artery, a shunt through the anterior communicating artery. Neither the presence of a particular draining vein nor the type of the venous drainage when divided into superficial or deep had an influence on the outcome. Nor was the size of the lesion of significant importance. The bearing of these findings on the value of established grading systems is discussed and a new grading system is proposed.


Are there typical localisations of lumbar disc herniations? A prospective study. A prospective intra-operative analysis of the location of lumbar disc herniation was performed in 131 patients with verified 54% contained (incomplete) and 46% non-contained (complete) lumbar disc herniations. Bulging discs or protrusions are not included in this study. Complete disc herniations occurred more frequently in the upper lumbar spine. The localization of the lumbar disc herniations within its segment showed no correlation to the affected level. 64% of the disc herniations were located medio-laterally, 20% laterally, 12% within or lateral of the intervertebral compartment and 5% in the midline. Nearly one third of all herniations were found at the level of the disc space. Medio-lateral disc herniations were displaced more often in a caudal direction, lateral herniations were found displaced upwards and downwards with similar frequency while extraforminal herniations migrated significantly more often in a cranial direction. The pathomechanism and anatomical pathways of disc fragment migration are discussed on the basis of a new concept of the anterior extradural space.


Postoperative spondylodiscitis: results of a prospective study about the aetiology of spondylodiscitis after operation for lumbar disc herniation. In 412 patients undergoing surgery for herniated lumbar discs from September 1986 to September 1987 and from January 1988 to July 1989 a microbiological specimen was taken from the intervertebral disc space and from the cover of the operating microscope. Also the tips of the wound drains were examined microbiologically after removal. 17% of the patients had a positive bacteriological culture from their intervertebral disc space; 12% of the specimen from the operating microscope were positive. These results favour the hypothesis that intra-operative contamination of the disc space, in contrast to haematogenous spread, causes spondylodiscitis. On the other hand we saw during this time course only one case of clinical spondylodiscitis, which implies a possible involvement of other predisposing factors such as pre- or perioperative infections or compromised patient immunologically. It is also possible, that the routine application of local antibiotic or antiseptic solutions into the disc space at the end of the operation could decontaminate the operative site and prevent clinical infection despite positive culture findings.


Clinical outcome and cognitive impairment in patients with severe head injuries treated with barbiturate coma. This study reports on clinical outcome in 38 patients with severe head injuries (posttraumatic coma for 6 hours or more) treated with barbiturate coma because of intracranial hypertension. Eighteen patients died, 4 patients remained in a severely disabled or a chronic vegetative state, and 16 patients reached the levels good recovery/moderate disability. Six of these patients returned to work or school full time, 4 for half time and 3 were in a rehabilitation program. Fourteen patients were subjected to a comprehensive neuropsychological assessment. All patients except one exhibited varying degrees of cognitive dysfunction and 6 patients had signs of personality change. The quality of life for the majority of surviving patients was relatively good but the positive effects of barbiturate coma therapy in the age groups over 40 years appeared to be limited.