Computer simulation of metabolism in pyruvate-perfused rat heart. I. Model construction.

A computer model of energy metabolism was constructed for the pyruvate-perfused rat heart subjected to a sudden increase in work load. The model construction techniques are explained and justified. Hypotheses defining a plausible sequence of physiological events resulting in the observed behavior of the organ were arrived at from the measured metabolite time profiles. There is a lag in increasing pyruvate utilization following the work-jump. A transient increase in fatty acid oxidation is required to account for the observed respiration rate. The observed increase in lactate production of this preparation is due to a transient "burst" of glycogenolysis after which the remaining lactate is imported from the interstitium and oxidized, reversing lactate dehydrogenase and hence the alpha-ketoglutarate-malate portion of the malate-aspartate shuttle.


Computer simulation of metabolism in pyruvate-perfused rat heart. III. Pyruvate dehydrogenase.

A physiologically and biochemically realistic model of the regulation of pyruvate dehydrogenase complex (PDH) was constructed for the perfused rat heart. It includes conversion between inactive (phospho) and active (dephospho) forms by a specific protein kinase (PDHK) and phosphoprotein phosphatase (PDHP). The activity of the tightly bound PDHK is influenced by synergistic activation/inhibition by acetyl CoA/CoASH and NADH/NAD. PDHK in this simulation was more sensitive to the fraction of ADP that was Mg2+-chelated than to the ATP-to-ADP ratio. Ca2+ stimulates binding of Mg2+-dependent PDHP to the complex; the bound enzyme was considered to be the active species. The fraction of PDH in the active form, rather than substrate and inhibitor levels, determines PDH activity under these conditions. This fraction depends on the present value and recent history of the difference between PDHK and PDHP activities. Both of these are active continuously and continuously control PDH.


Computer simulation of metabolism in pyruvate-perfused rat heart. IV. Model behavior.

The behavior of a computer model of energy metabolism was determined for perfused rat hearts utilizing pyruvate as sole exogenous fuel and subjected to a rapid increase in work load. Computer-generated metabolite profiles, which are solutions of the differential equations for 1 min elapsed time, closely match 12 experimental curves (involving 120 concentration measurements) and exhibit the following properties. The computed cytosolic pyruvate level oscillates due to large changes in the rates of the processes that produce and consume this metabolite. Cytosolic Mg2+ seems to act as a coordinated controller of glycolytic enzymes; its transient increase permits a transient increase of glycolysis without an accumulation of glucose 6-phosphate. Lactate is exported to the interstitium by a lactate permease and then reimported and oxidized. As a result, the malate-aspartate shuttle reverses direction, and the Krebs cycle is "unspanned."


Ontogeny of feeding controls in suckling and weanling rats.

To rationalize conflicting data in the literature, the latency of attachment of fed and fasted rat pups to the nipples of their anesthetized mother has been studied at various postnatal ages. At 10 and 14 days of age, the mode of fasting had a critical effect on the results: pups fasted in a 30 degrees C incubator had shorter attachment latencies than fed pups, whereas when pups were fasted in a 34 degrees C incubator or with a nonlactating foster mother at room temperature, their latencies were no different from those of fed pups. Thus maternal deprivation has an important influence on attachment latencies, unless other steps are taken to maintain the body temperature of fasted pups. When this variable is controlled, it is apparent that at 10 and 14 days of age, the feeding behavior of rat pups is not related to nutritional status. In contrast, from 17 days onward, latencies of fed pups were significantly longer than those of faster pups, regardless of the mode of fasting. This appearance of appetitive behavior during the 3rd postnatal wk was shown to have a temporal correlation with the beginning of weaning, as measured by the appearance of chow in the stomachs.


Regulation of cardiac output during rapid volume loading.

Interactions between heart rate (HR) and the Frank-Starling mechanism in augmenting cardiac output (CO) during acute volume loading were studied in dogs under varying conditions. In normal conscious dogs with low HRs of 70--90 beats/min, end-diastolic diameter (EDD) was maximal and CO was increased reflexly by cardioacceleration. By contrast, anesthetized open-chest dogs with high HRs ranging from 140 to 160 beats/min, responded with bradycardia and CO was adjusted solely by increasing stroke volume (SV). In anesthetized open-chest dogs with low HRs, EDD was less than maximal and increases in both HR and SV contributed to augment CO. These data show that both the cardioacceleration reflex and the Frank-Starling mechanism are important determinants of the cardiac response to elevated preload. Although the relative contribution of each control mechanism varies with initial conditions, their interplay extends the range of cardioregulation beyond that attainable by either loop operating alone.


Sinovagal interaction in arterial pressure restoration after 10% hemorrhage.

The summation between the carotid sinus baroreceptor reflex system (CS system) and the vagally mediated reflex system (V system) was studied as they restore mean arterial pressure (MAP) after 10% quick hemorrhage in splenectomized conscious dogs chronically instrumented with catheters for pressure measurement and hemorrhage. The experiment was repeated under nerve-intact condition (intact), with cold block of the vagi ([V]), after carotid sinus denervation (CS), and CS plus [V] situations. MAP falls at 1.5 min after the hemorrhage were 7.2 in intact, 24.7 in [V], 36.0 in CS, and 67.6 in CS + [V] mmHg. When we calculated the open-loop gains of CS and V systems assuming a simply additive summation between them a self-contradiction occurred. To avoid this contradiction, it was necessary to assume that CS and V systems interact in a facilitatory manner. Mean open-loop gains calculated under this assumption were 1.64 for the CS system alone, 0.89 for the V system alone, and 6.59 for the interacting component between them. These intriguing results warrant further analysis of the summation between the two reflex systems.


Effects of jejunoileal bypass on meal patterns in genetically obese and lean rats.

Jejunoileal bypass surgery, designed to reproduce the human operation (long bypass) was contrasted with a short bypass of only a few centimeters of ileum in both genetically obese rats and their lean littermates. In comparison with the short-bypassed rats, long-bypassed rats of both genotypes lost weight and reduced food intake. When adjustments were made for group differences before surgery, no significant differences were detected in the effectiveness of the operation on the two genotypes. The reduction in food intake was accomplished by a decrease in meal size and an increase in intermeal interval. Food intake gradually returned in the long-bypassed rats toward its level in the short-bypassed rats. This increase was accomplished by an increase in meal size alone. Intermeal intervals remained prolonged. In the long-bypassed rats, compared with the short, meal duration was initially elevated and gradually increased more than did meal size, indicating a great slowing of eating rate. Water intake was unaffected, but water-to-food ratio was elevated initially and gradually declined in the long-bypassed rats. Learned food aversion, dehydration, and gastrointestinal and metabolic alterations due to malabsorption are mentioned as possible contributors to the reduction in food intake, but none of these alone can account for all the changes in meal pattern by which intake reduction is accomplished.


Rate of generation of myocardial power density normalized by cardiac frequency.

We introduce a frequency normalized, power averaged, rate of generation of power density (FARPD) that extends the range of applicability of the averaged rate of generation of power density (ARPD) to any cardiac frequency encountered in experimental or clinical situations. Normalization eliminates the frequency-dependent mathematical artifacts arising during the computation of quantities containing time derivatives of the pressure, while preserving the effects of changes in heart rate on the cardiac muscle itself (Bowditch type of phenomena). The distribution of normal values in a group of 51 control dogs was very close to the standard normal distribution. These values had no statistically significant differences with those of a smaller control group studied by independent investigators. Isoproterenol and propranolol produced highly significant statistical changes in FARPD. Alterations in pre- and afterload produced changes that were not significant for the former and significant at the 5% level for the latter. These changes were small when compared to those resulting from typical inotropic interventions.


Influence of enteric parasitism on hormone-regulated pancreatic secretion in dogs.

The objective of this study was to test the hypothesis that enteric parasites affect pancreatic secretion in their host. Pancreatic bicarbonate and protein outputs were studied in dogs with gastric and pancreatic fistulas to determine the secretory response to exogenously administered secretin and cholecystokinin and to intraduodenal stimulation with hydrochloric acid and sodium oleate to release endogenous hormones. Bicarbonate and protein concentrations in pancreatic juice were measured prior to infection with Trichinella spiralis and at various periods during primary and secondary infections. Dose-related increases in secretory activity were observed in uninfected hosts in response to all stimuli. Infected dogs responded like controls to exogenous hormones, but showed reduced secretion under duodenal stimulation during the 1st wk of primary infection. This altered response returned to normal 3 wk after primary infection and did not occur following secondary infection. Results support the conclusion that reduced pancreatic secretion is associated with enteric parasitism and is due to a defect in hormone release or in the supply of hormone available for release.


A commitment law for patients, doctors, and lawyers.

The author proposes a model commitment law that balances the sometimes conflicting points of view among patients, doctors, and lawyers about this subject. Paternalism is affirmed, while safeguards are provided. It is argued that absent patient incompetency to consent to or refuse treatment, or absent an emergency, mental patients should not be treated involuntarily. The author believes that a different procedural approach is required depending on whether the patient is committed under the parens patriae or police power of the state.


Violent deaths among the young: recent trends in suicide, homicide, and accidents.

Violent deaths (suicide, homicide, and accidents) are the leading cause of death in people aged 1--39 in the United States. All three types of violent death may represent suicidal tendencies. Among early (10--14 years), middle (15--19), and late (20--24) adolescents, suicide and homicide rates increased with age and have doubled from 1961 to 1975. Accident rates increased with age but have changed little over the 15-year period. Suicide, homicide, and accidents increased dramatically between the 10--14-year-old age group and the 15--19-year-old age group; suicide and homicide rates were remarkably parallel over time; and suicide rates among young white people were higher and increased more than those among young nonwhite people.


Analgesia to painful stimuli in affective illness.

Patients with bipolar and unipolar affective illness (N = 76) were compared with 48 control subjects on a psychophysical pain rating procedure using both threshold and signal detection analysis. Affectively ill patients were more analgesic than controls, and depressed men were significantly more analgesic than depressed women or control subjects. Bipolar men showed a different pattern of analgesia than unipolar patients. Pain appreciation in depressed patients may be related to endogenous opiate-like substances; this could be assessed in narcotic antagonist studies of pain-tolerant depressed subjects.


Adults' reactions to the death of a parent: a preliminary study.

The authors conducted a systematic psychodynamic investigation directed explicitly toward the bereavement reactions of people who have lost a parent during their adult life. They conducted a single in-depth interview of 14 people with a mean age of 32.4 years who had experienced the death of a parent in the last 3--20 months. The authors present clinical data illustrating several themes, including the importance of the last meeting with the parent, the experience of grief and aggression, coping resources, and growth-oriented aspects of the bereavement process. They also make a number of suggestions regarding clinical practice and further research.


Developing a curriculum in psychogeriatrics.

Psychiatric problems are rampant among the aged, yet the psychiatric profession has not developed sufficient resources for training the necessary number of practitioners able and willing to treat elderly psychiatric patients. The management of psychiatric problems in old age differs substantially from that in younger age groups. The elderly patient is likely to have multiple needs and to require diverse services. Fundamental goals in training geriatric psychiatrists should focus on differential diagnosis and treatment, pharmacologic issues, consultation, community resources, and psychiatric, medical, and psychosocial aspects of care. The authors describe a curriculum tailored to meet these goals.


Models of a heroin epidemic.

Heroin addiction may be considered an epidemic disease that is communicated by people who are addicted to the drug. It has been suggested that the most recent epidemic in the United States had its peak incidence in 1969. The age of heroin addicts entering treatment has increased systematically from 1973 to 1976 at a rate of less than one year of age per calendar year. This pattern is consistent with a moderate decline in a national heroin epidemic or a geographical migration of the epidemic from more to less populated areas. There are also seasonal trends in the age of admission to treatment.


A new method for treating "headaches".

The author describes a 10-week study designed to gain some understanding of how to treat patients who have suffered for a long time with headaches that have not been alleviated by many attempts at treatment. Fourteen patients whose chief complaint was this kind of headache were given varying amounts of perphanazine and amitriptyline with the direct suggestion that these drugs would be helpful. This treatment appeared successful for 10 of the 14 patients at 6-month and 3-year follow-up.


Opiate addiction and suicidal behaviors.

The authors tested the hypothesis that people addicted to opiates manifest more psychopathology in areas that have been identified as predictors for high risk of suicidal behavior than do normal control subjects. They gave 278 patients in a methadone maintenance program and 207 normal control subjects the index of Potential Suicide (IPS), a scale designed to assess suicidal risk. Using discriminate function analysis, the authors found that 87% of 100 of the methadone patients and 98% of 100 of the normal control subjects were correctly identified on the basis of the IPS data.


Implicit preadmission screening criteria in an alcoholism treatment program.

The fact that alcoholism programs are biased in terms of the kind of patients admitted to treatment is well recognized. The authors examined the possible bias of preadmission screening procedures in an alcoholism treatment program and investigated some of the criteria used by staff clinicians in determining an applicant's acceptability for treatment. They found that accepted and rejected applicants had highly similar characteristics, differing only in age (accepted applicants were slightly younger than those rejected) and source of referral. The overall findings suggest that clinicians implicitly evaluate problem drinkers along dimensions related to their perceived "treatability" in a given therapeutic setting.


Juvenile male sexual assaulters.

This study compares the psychiatric, neurological, and psychoeducational status of sexually assaultive male juveniles and other violent juveniles. The authors found that juvenile sexual assaulters suffered from neuropsychiatric problems similar to those of other violent juveniles, had committed violent acts other than sexual assault, and had had seriously aberrant behavior since early childhood. The findings contradict prevailing assumptions that sexual assaults by juveniles are rare occurrences and that juvenile sex offenders have low rates of recidivism. Theoretical and treatment implications are discussed.


Hypnotic deafness: a psychophysical study of responses to tone intensity as modified by hypnosis.

Hypnotic deafness was suggested for 1000 Hz tones presented in random orders at seven intensities between 17 and 70 db. Subjects were 70 college students stratified into four levels of hypnotic susceptibility, ranging from low to high. Four conditions were presented within a single session. Two conditions tested normal hearing, one in waking and one in hypnosis; two tested reported loudness of the tones as reduced by hypnotic suggestion. The method of magnitude estimation was employed. Hearing reduction was found to correlate .59 with hypnotic susceptibility in the total sample. Few high hypnotizables reduced their hearing to zero; their mean residual hearing during the deafness conditions was 55% of normal. Power functions for the relationship between tone intensity and magnitude estimates for conditions of normal hearing and deafness were found to be relatively parallel and orderly, differing primarily in intercept value. Order effect anomalies are discussed. The "hidden observer" method showed that for 4 of the 70 subjects the covert hearing was found to be at least 20% greater than that reported overtly within hypnotic deafness and approached normal hearing. As in our previous hypnotic analgesia research, not all subjects who reduced their hearing significantly gave subsequent covert reports which differed from reported overt hearing. Discussion is given for evidence of two levels of information processing during hypnotically suggested perceptual distortions.


Cognitive processes in the solution of three-term series problems.

This study investigated the nature of strategies used in solving the three-term series problem. Three presentation modes (auditory, visual/sequential, and visual/simultaneous) were crossed with two question positions (before-premises and after-premises), for a total of six methods of problem presentation. Both high-spatial/imagal and low-spatial/imagal problems were employed, the assumption being that better performance on high-spatial/imagal problems reflected the use of a spatial/imagal strategy, while equal performance on both types of problems indicated the use of an alternative, perhaps verbal, strategy. It was hypothesized that different presentations would lead to differences in memory demands, input/processing interference, and mathemagenic behaviors, and thus to different problem-solving strategies. Response data and subjective reports confirmed this prediction. Results were discussed in terms of the Clark-Huttenlocher controversy (H. H. Clark, Linguistic processes in deductive reasoning, in Psychological Review, 1969, 76, 387--404; J. Huttenlocher, Constructing spatial images: A strategy in reasoning, Psychological Review, 1968, 75, 550--560).


Stimulus and procedural determinants of the forgetting of conditioned fear.

Two studies investigated factors believed to influence the retention of acquired fear in rats. The results show clearly that the lack of forgetting over 24-hr interval reported by previous investigators is due to a depression of performance on the immediate test (3-min retention interval) resulting from the procedure of not handling the rats during conditioning but then handling them on every trial during the retention test. In accord with the McAllister's interpretation of related results, the depression of performance after short retention intervals may be due to a lack of generalization from training to the testing situation. As the retention interval is lengthened, the amount of generalization increases and escape performance improves on a relative basis. The nature of the retention function may be severely distorted by selection of an inappropriate paradigm for its evaluation.


The repetition effect in judgments of temporal duration across minutes, days, and months.

Three experiments assessed the stability of the repetition effect in time judgment. In Experiment 1, subjects (N = 18) produced intervals ranging from 8 to 31 sec in a two-phase procedure with a five min rest between phases. In Experiment 2, subjects (N = 20) made verbal estimates of intervals ranging from 8 to 20 sec with a 48-hour delay between phases. Experiment 3 involved daily productions by three subjects of intervals ranging from 8 to 54 sec over several months. The slope of the psychophysical function increased across phases in Experimental 1, declined (as expected for estimation) across days in Experiment 2, and increased across months in Experiment 3. It was concluded that the repetition effect is relatively permanent and thus more similar to habituation than to sensory adaptation.


Integration of verbal and visual information as evidenced by distortions in picture memory.

Subjects were presented with a series of pictures, some of which were general (girl walking down the path) and others specific (girl hiking down the path). These pictures were matched with sentences which were either general or specific ("The girl is walking [hiking] down the path.") Subsequently, a forced-choice picture recognition test was administered in which subjects saw pairs of pictures and indicated which member of each pair they had seen before. It was found that labelling the picture with a sentence containing a specific verb substantially increased the likelihood that the specific picture corresponding to that verb would subsequently be falsely recognized. The results are discussed in terms of current theories of memorial representation.


Causes of fetal and neonatal mortality by race in a selected U.S. population.

In a large prospective study (1959--1966), the perinatal mortality rate for U.S. Whites was 34 deaths per 1000 total births, for Blacks 51/1000, for Puerto Ricans 41/1000, and for Orientals 23/1000. A number of disorders were responsible for these differences. Premature rupture of the fetal membranes occurred 92 per cent more often in Blacks than in Whites, marked placental growth retardation 56 per cent more often, amniotic fluid infections 45 per cent more often, and major congenital malformations 15 per cent more often. Most other disorders were less common in Blacks than in Whites. Stratifying the data by selected factors, such as prepregnancy body weight and antenatal medical care, eliminated or greatly reduced almost all of these interracial differences. The only major unexplained differences remaining were an excess of amniotic fluid infections and major congenital malformations in Blacks, and an excess of abruptio placentae and large placental infarcts in Whites.


Cesarean section, fetal monitoring, and perinatal mortality in California.

The rate of cesarean section in California has been growing at a compound rate of about 10 per cent per annum since 1969, coinciding with the advent of fetal monitoring. It is of interest, therefore, to study the distribution and efficacy of obstetric interventions. Information derived from the 1977 California birth cohort and a survey questionnaire was used to study the factors associated with the rate of cesarean section in 323 hospitals. Significant positive correlations were observed between the cesarean rate (CSR) and hospital factors indicative of a high degree of technology, including the proportion of labors electronically monitored. Significant negative correlations were observed between the CSR and hospital-specific variables suggestive of socioeconomically underprivileged patient populations. Other factors being constant, hospitals characterized by prepayment health care financing also had lower CSRs. A standaridized mortality ratio (SMR) based on 2.3 million births in the 1970--1976 cohorts was used to adjust the 1977 hospital specific perinatal mortality rates for birth weight, gestational age, sex, race, and plurality. The results show that hospitals which intervene technologically in a large proportion of births have lower risk adjusted perinatal mortality rates.


An evaluation of efforts to educate mothers about child development in pediatric office practices.

The efforts expended by pediatricians in a variety of private practice settings to educate mothers of first-born children about child behavior and development were examined in relation to various outcome measures of mother and child functioning over a time period of one-and-a-half years. Mothers learned more about child development in group settings than in solo practice settings, but differences between medical groups with and without nurse practitioners were not significant. Mothers receiving care from pediatricians who made at least a moderate effort to teach, learned more about child development, described more use of positive contact with their children, and felt they were helped more in their childrearing efforts than did mothers receiving care from pediatricians who made little effort to teach. However, there were no significant differences in measures of the child's developmental status related to physician teaching input, and mothers exposed to higher levels of teaching input reported more behavioral problems with their children. The most important predictor of the child's developmental status at 18 months of age was the amount of positive contact between mother and child at one year. It is suggested that the effects of changing the frequency of well-child visits on the mothers' interaction patterns with their children and on their feelings of being supported by the physician be ascertained before making recommendations about the optimal number of such visits.


The risk of low birthweight.

Descriptive analyses of birthweight for single live births in the United States during 1974, using birth certificate information, show that several factors are associated with a high incidence of low birthweight babies. Multivariate analyses were performed to determine correlates of low birthweight. When other factors are held constant, race not white, previous reproductive loss, short interpregnancy interval, out-of-wedlock birth, no prenatal care, and maternal age under 18 years or over 35 years each increase the risk of having an infant of low birthweight. High birth order and maternal education under 12 years of schooling were not consistent risk factors for low birthweight. Odds ratios are presented and the method for combining these, to estimate the risk for an individual mother having a low-birthweight infant, is illustrated.


Treatment of women in childbirth: implications for family beginnings.

This paper presents an ethnographic analysis of a woman's interaction with staff members during the early stage of labor, focusing on the factors that shape the childbirth experience. The observational data were gathered in several hospitals as part of a study of the medical context of childbearing. The paper presents a model of naturalistic inquiry into the transition to parenthood. Nurses and physicians are found to offer arbitrary, uniform, and often inappropriate responses to birthing women that may inhibit well-being.


A comparison of growth: Spanish-surnamed with non-Spanish-surnamed children.

Weight, height, and head circumference measurements of 4,167 Spanish-surnamed school-aged children were compared with similar data from 2,322 non-Spanish surnamed children who resided in the same Denver, Colorado neighborhoods. These data were also compared with data from six other studies. Both male and female Spanish-surnamed children were found to weigh less, be shorter, and have smaller head circumferences than non-Spanish-surnamed children living in the same Denver neighborhoods. The sizes of the children in these two populations residing in lower and lower-middle class neighborhoods were closer to each other than to the sizes of children from middle and upper-middle socioeconomic classes as measured in previous studies or to the sizes of children in the recently published cross-sectional National Center for Health Statistics study. Such comparisons suggest that growth retardation is more a reflection of socioeconomic factors than of ethnic-genetic factors.


Attitudes of mothers toward sex education.

Data are presented on the attitudes of mothers from the entire social class spectrum toward content and timing of sex education for children (CT-Attitudes), and also toward sex education in school (S-Attitudes) in two California communities in 1969. Findings underscore the necessity to consider these two attitudinal variables separately. As a result of their separation for study purposes, it was possible to arrive at a four-fold typology or grouping of mothers: 1) CT liberals in favor, and 2) CT liberals opposed to sex education in schools, 3) CT conservatives in favor, and 4) CT conservatives opposed to school programs of sex education. It is inferred that educational planners need to pay due regard to the sentiments of all four maternal groups and all social classes in developing sex education programs for families and for school children.


Evaluation of the relationship of sodium in drinking water and toxemia of pregnancy.

This study is a retrospective case comparison analysis of the relationship of water-borne Na+ and toxemia of pregnancy as a part of a continuous investigation at our facility on the role of various water constituents in human chronic disease. Five hundred thirty-seven toxemic pregnant women delivered at Jefferson Davis Hospital, Houston, Texas, during 1976 were matched by age, race, obstetrical history, and month of delivery to 537 non-toxemic controls. Sodium concentration in each patient's drinking water was derived, based on her address, from earlier prepared maps of sodium distribution in Houston's water supplies. Paired t-tests were performed to compare the Na+ levels, which varied from 19 to 250 mg/l in water supplies of cases and controls. Odds ratio analysis was used to test for the presence of a gradient in occurrence of toxemia in parallel with the gradient of Na+. No significant impact of water-borne Na+ in the indicated range was observed. Further studies incorporating still higher ranges are contemplated.


Measles in a partially immunized community.

During the investigation of a measles outbreak in a rural community, a spectrum of illness was observed which ranged in severity from a brief febrile illness to one characteristic of typical measles. Unimmunized children were more apt to develop measles (p less than 0.001) than were immunized children. However, a proportion of both the immunized and unimmunized children developed a milder, "measles-associated," illness. Employing a logistic model, it was demonstrated that the probability of developing either measles or "measles-associated" illness decreased with increasing age at immunization but was not affected by the interval since immunization.


Policies toward medical technology: the case of electronic fetal monitoring.

Electronic fetal monitoring (EFM) is an example of a medical technology that has been widely accepted since its introduction in the mid-1960s. However, review of the literature does not provide convincing evidence of EFM efficacy, and four recent, controlled, clinical trails show little if any benefit in terms of preventing death or long-term disability of the baby. Public and private policies have largely acted to encourage use of EFM, and none have acted to slow or prevent its spread. This need for mechanisms to assure the timely evaluation of new medical technologies before they are accepted as a medical practice has led to a new medical devices program in the Food and Drug Administration, consensus development groups at the National Institutes of Health, and congressional legislation to establish a new National Center for Health Care Technology.


Validation of a poison prevention program.

The effectiveness of an empirically designed poison warning label and an educational program for three and four year old children was assessed in four groups of 39 such children, with one group serving as a control. The educational program appeared to improve intellectual (verbal) awareness of poisons, the label to improve visual discrimination, and the combination of the two to have the greatest overall impact.


Response of low income women and abortion facilities to restriction of public funds for abortion: a study of a large metropolitan area.

During the first five months after the restriction of public funds for abortion, a large percentage of low-income women seeking abortions in a metropolitan area in Texas obtained abortion that were partially subsizied using a combination of reduced clinic fees and public funds for ancillary non-abortion services. Their own personal funds made up the difference between the subsidy and the full cost of the procedure.


Popliteal hiatus of the lateral meniscus. Anatomy and measurement at dissection of 10 specimens.

The popliteal hiatus is the opening defined by the fascicles of the lateral meniscus, which permits the popliteal tendon to pursue its course from the tibia to its femoral attachment. The medial border of the popliteal hiatus is the body of the meniscus. Ten fresh-frozen knee specimens from human adult males (with no evidence of previous surgery to the knees) were dissected. The joints were disarticulated so that only the lateral structures remained intact. The perimeter of the meniscal attachment anterior to the hiatus measured 4.2+/ - 0.3 cm, and the perimeter posterior to the hiatus measured 3.4 +/- 0.5 cm. The total perimeter of the lateral meniscus was 8.9 +/- 0.7 cm. The length of the superior fascicle of the lateral meniscus was 0.9 +/- 0.2 cm. In this series, the length of the hiatus was 1.3 +/- 0.1 cm. The anatomy of the popliteal hiatus was constant. The popliteal hiatus is an anatomical structure and must be differentiated from pathologic lesions common to the same area.


Bladder trauma in the long-distance runner.

The occurrence of hematuria as a short-lived and occasional event in a number of long-distance runners appears to be secondary to bladder contusions caused by a combination of exertional forces and intraabdominal pressure producing repeated impact of the flaccid wall of the bladder against the bladder base. The bladder may be empty or nearly empty while the runner is in action. This permits apposition of the surfaces of the bladder. The variability of the state of filling of one's bladder from one occasion to another may therefore account for the inconsistency of occurrence of hematuria in the same runner.


An epidemiologic study of tennis elbow. Incidence, recurrence, and effectiveness of prevention strategies.

An epidemiologic study of the incidence and recurrence of tennis elbow among over 500 tennis players (278 men, 254 women; age range, 20 to 50 years) indicated that age and amount of playing time per day were contributing factors to the injury. Both incidence and recurrence rates increased with age. An interactive effect of playing time and age was observed with increased playing time associated with higher incidence at younger ages. Larger grip size was also associated with higher incidence in the older group. These findings were interpreted as being consistent with the hypothesis that tennis elbow is a degenerative disease, the onset of which is hastened by overuse of the arm and elbow. Changes in stroke technique and types of racket were successful in preventing recurrence. Least successful was the forearm brace.


Injuries in women's gymnastics. A 5-year study.

In this 5-year study of women gymnasts, 70 participants (i.e., one woman for one season) sustained 66 major injuries (i.e., brought to the attention of a physician and produced disability). Forty-seven of the 70 athletes sustained injuries. The trunk had the lowest incidence of injuries (11), the upper extremity had 20, and the lower extremity had the highest incidence (35 injuries). Two categories, stress or trauma, segregated the injuries and provided rationale for the high incidence of injuries on this team. These athletes were of national caliber. They were constantly trying to improve performance. They engaged in intensive practice and difficult maneuvers. The self-motivation of these women increased the number of injuries caused by stress (a total of 21); the combination of intensive practice and the maneuvers is responsible for the traumatic injuries (45). From this evidence, women's gymnastics should be recognized as a hazardous sport for the competitor. Risk factors should be evaluated constantly by her, the coach, and the team physician.


The saphenous nerve: its course and importance in medial arthrotomy.

Both lower extremities of 10 cadavers (20 specimens) were dissected to delineate the course of the saphenous nerve and its two major divisions (sartorial and infrapatellar branches). The course of the saphenous nerve followed the standard text description, except at the point in the sartorius muscle where the infrapatellar branch exited to become a subcutaneous structure. The location of this branch varied slightly in each cadaver but was the same for both lower extremities in the same cadaver. The location of the sartorial nerve and its relationship to the tendons of the pes anserinus was consistant in all 20 specimens. Since 69% of a group of 75 patients found altered sensation significant after routine sectioning of the infrapatellar nerve following medial meniscectomy, a group of surgeons at the University of Michigan is now protecting the infrapatellar branch of the saphenous nerve at operation. Early results on a small number of patients indicate that no alteration in sensation occurs if the nerve is carefully retracted.


Injury patterns in children and adolescent skiers.

Over 3,500 students from five major high schools in the Seattle metropolitan area were studied as to skiing injuries. Each had skiied an average of 13.3 days. The average age of t'he group was 13.5 years, the ages ranging from 3 to 19 years. The students 10 years and under had the lowest incidence of injuries, those aged 11 to 14 years had the highest over-all injury rates, and the group 15 years of age and over laid midway between these two groups in injury rate. There was no evidence in the study that the open physis led to a higher incidence of epiphyseal injuries. The knee was more commonly involved than the ankle, and sprains, contusions, and fractures followed in that order as far as injury rates were concerned. The female was more prone to injury than the male. Skiiers with greater ability had fewer injuries than those with less skill in this particular sport.


Neck motion in the high school football player. Observations and suggestions for diminishing stresses on the neck.

In a group of 40 high school athletes (height: 166.37 to 189.57 cm, average, 174.40 cm; neck circumference: 35.56 to 41.91 cm, average, 39.12 cm), the neck motions were studied in flexion and extension, clinically, radiographically, and cineoradiographically. Flexion ranged from 34 to 84 degrees (average 72 degrees) and extension from 21 to 64 degrees (average 45 degrees) without helmet and shoulder pads. In well-fitting equipment flexion ranged from 36 to 86 degrees (average 73 degrees) and extension from 12 to 56 degrees(average 34 degrees). No correlation was determined between the size of the athlete's neck and the range of motion. The size of the athlete's neck was important in the determination of maximum stresses in the neck. The helmets impinged on the shoulder pads or interscapular region; this impingement diminished tension on the anterior portion of the cervical spine in extension. The face masks impinged on the shoulder pads in flexion of the neck; this impingement diminished stress on the posterior musculature. Proper fitting equipment, conditioning neck exercises, and changes in the rules of the game so that abuse of the head and neck is not encouraged are some of the aspects that may reduce the risk of injury to the cervical region in football players.


Tennis injuries: prevention and treatment. A review.

When players are engaged in the sport of tennis, injuries may occur to the eyes, in the neck, to the shoulder and back, arm and elbow, wrist and hand, and feet. The key to prevention and treatment of these injuries is good coaching and a formal stretching and strengthening program. The drooped "tennis shoulder" of professionals and senior tennis players is a natural response to heavy use. Shoulder elevating exercises are useful when soreness is associated. The treatment of tennis elbow includes wrist extensor stretching, isometrics, and light weightlifting. When a player follows this program, injections or counterforce braces are rarely needed. It is important for the player to bring his racket to the examination so that his stroke mechanics and grip can be checked. Wrist soreness in a tennis player may denote a hamate hook fracture. Special radiographic views are needed to discern the fracture and it is treated with a short arm cast and little finger extension splint. Nonunion of a hamate hook requires excision. The calf pain prodrome of "tennis leg" requires rest and then a stretching program. Tennis shoes should have rolled heels and large toe boxes with reinforced toe bumpers. The physician may have to fashion soft inserts for the tennis shoes; arch supports may be insufficient.


Eye injuries in Canadian amateur hockey.

Two studies, one retrospective (1972 to 1973) and one prospective (1974 to 1975), CONcerning eye injuries incurred by hockey players were conducted by the Canadian Ophthalmological Society with questionnaires to its members. Responses to the questionnaires were analyzed by age, type of injury, cause (i.e., hockey stick, puck, or other means), and results to visual acuity. The results were also designated by organized or unorganized participation. Almost 300 eye injuries were reported in each study. In the first study, 13.7% of the injured players became legally blind as a result of the injury; in the second study, 16% became legally blind. Organized hockey produced more injuries than unorganized hockey. The majority of the injuries were caused by the hockey stick. The injuries were both intraocular and extraocular. The group of 11- to 15-year olds received the highest number of injuries, and the older age group had the higher incidence of blindness. Studies have led to setting more rigid standards, altering rules of the game, and selecting face protectors for hockey players. Older players who care for their equipment prefer the plastic shield face protectors, and the younger players (who complain of fogging and scratching of the plastic) prefer mesh protectors through which neither the stick nor the puck can penetrate. New high sticking (above the shoulder level) rules were included in the 1976 official rule book for Canadian amateur hockey.


Preoperative evaluation of pulmonary function.

Respiratory problems are a major cause of postoperative complications. Detection of the patient with subtle chronic obstructive pulmonary disease is essential to lessen the risk of respiratory complications in the postoperative period. In the patient with known chronic obstructive pulmonary disease, it is important to determine not only whether a lung lesion such as a neoplasm can be completely resected, but also whether the patient's cardiorespiratory reserve is adequate to allow the proposed lung resection. Detection of the patient at increased risk as well as evaluation of the ability to withstand surgery is discussed.


Anastomotic failure complicating total gastrectomy and esophagogastrectomy for cancer of the stomach.

Anastomotic failure complicated the postoperative course of 11 per cent of 350 gastric cancer patients who underwent total gastrectomy and esophagogastrectomy and was responsible for 33 per cent of all operative deaths. The extent of disease and the presence of tumor at the margin of resection did not prove to be significant factors in regard to the incidence of anastomotic failure. Gastrectomy combined with resection of other organs was associated with a significantly higher risk of failure. End-to-end esophagogastrectomy and esophagoduodenostomy appeared to be prone to failure, while Roux-en Y, jejunal pouch, and jejunal loop reconstructions were safer. Patients with severe intraabdominal or intrathoracic sepsis had a poor prognosis, and their management with surgical or conservative methods was ineffective. On the basis of these findings, alternatives to manual methods of visceral suturing should be considered.


Primary carcinoma of the gallbladder: review of 25 cases.

The records of 25 patients with carcinoma of the gallbladder occurring during a 5 year period were reviewed. The frequent relation of the disease with cholelithiasis and benign tumors has been widely recognized. Stones were present in the gallbladder in 92 per cent of the patients. In the majority of cases, a diagnosis of carcinoma of the gallbladder was not made clinically. The most common preoperative diagnosis was benign biliary tract disease. The mean survival time after operation was 7 months, and only five patients had a curative resection. The best hope for reducing the mortality from this disease lies in earlier cholecystectomy in patients with benign gallbladder disease.


Pelvic exenteration for advanced rectal carcinoma.

Twelve patients with advanced rectal cancer and no evidence of extrapelvic metastases underwent pelvic exenteration. The operative mortality rate was 8.3 per cent. Determinate 3 and 5 year survival rates of 54 and 37 per cent were achieved. Criteria for the selection of patients and techniques of supravesical urinary diversion are discussed.


Inflammatory tissue reaction in rabbit bowel injected with Crohn's homogenates.

Homogenates from the terminal ileum of a patient with Crohn's disease with granulomas were prepared as snap-frozen or fresh and were injected into the ascending colonic walls of New Zealand white rabbits. Control animals were injected with 1 per cent bovine serum albumin alone. The rabbit bowel was examined after 1 year, and lesions were noted in each of the rabbits injected with Crohn's disease homogenate, irrespective of the type of tissue preparation. The observed lesions were diffuse and occurred both at the injection site and in the terminal ileum. These changes were not noted in the control group. This work confirms earlier results in the same animal model and suggests that either fresh or snap-frozen homogenates will produce the intestinal lesion but that bovine albumin alone will not.


Tumor variation in the cancer family syndrome: ovarian cancer.

The Cancer Family Syndrome is a hereditary disorder (autosomal dominant), characterized by early onset cancer of the colon (particularly the proximal colon) and endometrium, with an excess of multiple primary cancers. Recent evidence reflects the possibility of an even broader tumor spectrum consisting of carcinoma of the stomach, the ovary, the kidney, and possibly other organs. A family with the cardinal features of the Cancer Family Syndrome is described, including two sisters and their mother who had ovarian carcinoma at early ages (38, 46, and 49 years). Two of these three women have shown unusual tolerance to cancer, despite invasion of the primary tumors. Implications for cancer surveillance and management are discussed.


Long-term cimetidine and anticholinergic therapy in patients with gastrinoma.

Two patients with gastrinomas were treated with cimetidine and an anticholinergic drug for greater than 20 months after exploratory laparotomy disclosed no solitary resectable tumor. Both have done well, and thus this therapy is recommended as a safe and effective alternative to total gastrectomy in reliable patients. Additional therapeutic methods are needed to control tumor growth.


Effect of surgical scrub on microbial population under the fingernails.

The effectiveness of two methods of presurgical hand preparation, the 10 minute routine scrub and the 90 second Hydroscrub, in reducing microbial numbers under the fingernails was determined. Bacteriologic cultures of 162 subungual areas of nine subjects revealed prescrub microbial counts of up to 1.9 X 10(5) colony-forming units per area. After the surgical scrub, bacterial concentrations were reduced to a different degree among the persons tested. The mean values of 3.0 X 10(3) to 7.8 X 10(3) colony-forming units immediately after scrub indicated that neither of the two methods tested reduced the microbial population under the fingernails of most persons to acceptable levels. The finding of high postscrub microbial counts under the fingernails is of particular interest and significance in view of the relatively low counts on the fingertips. On the basis of the results of this study, we conclude that degerming of the areas under the fingernails by present methods is not satisfactory. The implication of these findings is discussed.


Central dopamine receptors regulate blood eosinophilia in the rat.

Dopaminergic agents, dopa and apomorphine, affected biphasically the blood eosinophil count in the rat: low doses of the drug elevated, while high doses lowered it. The response to a high dose of dopa was retained in rats pretreated with an inhibitor of dopamine-beta-hydroxylase, U 10, 157, but prevented by a centrally acting dopa decarboxylase inhibitor, NSD 1015. This indicates that the eosinopenia observed after large doses of dopa is due to the action of dopamine formed from the precursor. As intracerebroventricular injections of Ldopa also produce eosinopenia, the central site of dopamine action is indicated. The eosinopenic response to apomorphine was antagonized by a dopamine receptor blocking agent, haloperidol. This indicates that some central dopamine  receptors are involved in the regulation of the eosinophil count in circulating blood. The hypophysis seems to play a crucial role in the phenomenon observed, as no eosinopenia was produced by dopa in hypophysectomized rats.


Intravenous administration of glycopyrronium: effects on cardiac rate and rhythm.

Intravenous administration of glycopyrronium in doses up to 0.2 mg, was associated with minimal changes in cardiac rate and rhythm. Sinus arrhythmia, nodal rhythm and occasional atrial ectopics were the dysrhythmias observed. There were no accompanying changes in blood pressure.


Analgesic effects of sublingual buprenorphine.

The analgesic effects of sublingually administered buprenorphine 0.4 mg have been compared with morphine 10 mg given intramuscularly in patients following operation. The results indicate a slower onset of action for buprenorphine but of much longer duration than morphine. There were no serious side effects or difference in their incidence between the two drugs.


The evaluation of analgesic drugs. The case for experimental methods.

The current status of the experimental, as opposed to the traditional clinical, approach to the evaluation of analgesic activity is examined in the light of recent observations made with the submaximal tourniquet and electric shock methods of inducing experimental pain. The results obtained indicate that the submaximal effort tourniquet technique shows an acceptable degree of sensitivity in detecting the analgesic activity of both narcotic and non-narcotic agents which is not the case with the electric shock method. These differences in sensitivities between two different experimental methods are examined and some possible explanations offered for the findings. It is concluded that some modern experimental methods may now provide a valid and desirable alternative to the clinical approach for the evaluation of analgesic agents.


Accidental intra-arterial injection of papaveretum during anaesthesia.

The circulatory depressant action of papaveretum was demonstrated when the drug was injected accidentally into the radial artery during neuroanaesthesia in the upright (sitting) position. The signs of air embolism were mimicked. The condition reponded promptly to a vasopressor given intravenously. There were no harmful sequelae to the patient's hand.


Valve replacement in carcinoid syndrome. Anaesthetic management for tricuspid and pulmonary valve surgery.

This report describes the anaesthetic management of a patient with carcinoid syndrome for cardiac catheterisation followed by replacement of the tricuspid and pulmonary valves. Apart from the precautionary use of aprotinin and steroids, routine techniques of anaesthesia and monitoring were used without complications attributable to secretions from tumour tissue.


Errors in fuel cell oxygen analysers during NEEP.

A fuel cell oxygen analyser was found to underread during the application of negative end-expiratory pressure. Further investigation revealed that air leaks into the analyser head through the plastic housing and causes the analyser to read low. A remedy is suggested.


High tracheal bifurcation.

A case study is reported, outlining abnormal tracheobronchial anatomy in an adult male presented for thoractomy. The anesthetic technique is described. Ureteric catheters were used as introducers for the selective intubation of each main bronchus. The problems encountered postoperatively are also discussed.


The nature and incidence of complications of peripheral arterial puncture.

Follow-up of the sites of 839 peripheral arterial punctures has confirmed the technique as safe and free from major sequelae. Minor complications, mainly bruising and tenderness, occurred at 39% of sites; this incidence is much less than that previously reported following short-term arterial cannulation. At only 2% of sites was there any significant pain or tenderness. There was a small incidence of pulse diminution particularly at the radial site but no case of arterial occlusion. The use of a smaller needle (23 s.w.g.) significantly reduced the overall incidence of complications.


Total intravenous anaesthesia for computerised axial tomography.

A method of anaesthetising patients for computerised axial tomography using an intravenous infusion of alphaxalone/alphadolone as the sole agent is described. Its successful use in 120 patients of all ages has led to a better understanding of the mode of action of the drug and suggestions are made about its use in more general anaesthetic practice.


Negative surplus charge of coated erythrocytes.

The effect on the net negative surface charge of single or multiple coating of erythrocytes was studied on human group A red cells previously washed and fixed. Single coating with either group A antiserum or protectin decreased the electrophoretic mobility of erythrocytes by 16% and 13%, respectively. Following an incubation in group A glycophorin or bovine submaxillary mucin of agglutinin coated cells, the electrophoretic mobility was restored or slightly increased compared with uncoated erythrocytes. Upon repeating this scheme, the second agglutinin binding again reduced these cells' cytophoretic mobility, and they were accelerated once more by a second coating with acid glycoprotein. Intensity and homogeneity of colloidal iron staining of uncoated and variously coated erythrocytes reflected their electrophoretic retardation and acceleration, respectively.


[The morphology of the lacrimal gland of Herpestes edwardsi (Viverridae) (author's transl)].

The morphology from the Glandula lacrimalis of the mongoose Herpestis edwardsi is described. Light microscopical observations show that the acini consist of ramified, mucous tubules and of serous demilunes (Fig. 1, 2). Thus the morphology of this organ of the mongoose differs from those of other species remarkably. Electron microscopical the demilunes and the tubules show characteristical granula which arise from Golgi-vesicles. The granula fuse and eliminate their contents into the clearing by exocytosis. In the demilunes there are granula of different size and shape. Their contents aremostly dense and cristallize sometimes to rod-shaped, lamellar structures (Fig. 5). The cells of the tubules contain abundant bizonal granula which seem to be in contact with the rER (Figs. 6,7). The epithel of the intra- and interlobular ducts includes membran-bounded osmiophilic substances. The cytoplasm of the cells is enforced by filaments which aggregate beneath the apical plasmalemma to a prominant terminal web-like layer (Fig. 9). Intercalated and striated ducts are lacking. The results are discussed with earlier findings at the Glandula lacrimalis of other species.


[The three-dimensional ultrastructure of the pancreatic acinar cell (authors transl)].

The pancreatic acinar cells of normal rats were studied by scanning electron microscope. A three-dimensional image is presented of the structure and arrangement of the zymogen granules as well as of the apical microvilli and the zymogen discharge in the pancreatic acinar cell. The study of these structures in physiologic and pathologic conditions by scanning electron microscopy can be recommended to support the understanding of findings obtained by light and transmission electron microscopy.


Morphology of the hypophysis of the freshwater teleost rhamdia hilarii (val., 1840).

The anatomical relationship between hypophysis and encephalon of the Bagre fish (Rhamdia hilarii, Val.) was studied. The subdivisions, morphology and the relative volume (%) of the different hypophyseal regions during the reproductive stage of the fish were also considered.


Ratio of rods and different cones in fishes of shallow sea.

The retinas of 4 fishes (Periophthalmus chrysopilos, Scorpaenoides marmoratus, Nemipterus bathybins, Taius tumifrons) were analysed. Rods were found to increase with depth but twin cones were not found to descrease with depth. A regional difference was also observed in the distribution of these elements in the retinas.


Arterial pattern of the spleen in the domestic fowl.

The authors describe the variations on the origin, number and vascularization areas of the splenic artery of 50 fowls, 34 males and 16 females, Gallus gallus, Indian River, of different ages, with medium weight of 2.133 g. The results were expressed in relative percentage figures and compared with the literature cited.


Macroscopic anatomy of the bronchial arteries.

Exact and detailed findings concerning a macroscopic anatomy of the bronchial arteries have not been presented. Moreover, positional relations of this artery to the adjacent organs had mostly been neglected, which offered an important key to identify the aberrant vessel in some cardiac malformations. The authors dissected the bronchial arteries from their origin to the pulmonary hilus in 40 Jpanese adult cadavers. Against the descriptions of textbooks of anatomy, 2 right and 2 left arteries in a body were most commonly observed. Therefore, 4 arteries could be distinguished, right superior, right inferior, left superior and left inferior, which passed along cranial and caudal borders of the corresponding bronchus respectively. Origins of these arteries were 1) right aortic intercostal artery, 2) right subclavian artery, 3) left subclavian artery, 4) aortic arch proximal to the left recurrent laryngeal nerve and 5) descending aorta distal to the above-mentioned nerve. As a rule, each of the 4 arteries above had a definite origin and course, as shown in Fig. 7. Postional relations of these arteries to the trachea, esophagus, thoracic duct, azygos vein and the left recurrent laryngeal nerve were also described.


[The distribution of sensory and motor axons of the intercostal nerves and their branches (author's transl)].

As it is well established that motor axons in general display a higher acetylcholinesterase-activity than sensory axons do, the histochemical method of KARNOVSKY and ROOTS (1964) was used for the differentiation of motor and sensory fibres in the intercostal nerves and their branches. In the paravertebral sections of the intercostal nerves of the upper segments 30--35% of the nerve fibres show a high enzyme activity and therefore were classified as motoric. The percentage of the motor fibres in comparable zones of the lower segments increases to 45%. Only 15% of the nerve fibres proved to be motoric in the parasternal sections of the intercostal nerves. In a histogram of the acetylcholinesterase-positive intercostal nerve fibres 2 peaks can be seen: one in the alpha-calibre class, the second in the gamma-class. There are more motor axons in the lateral cutaneous branch of the lower intercostal nerve than in upper ones. This may be explained by the participation of these nerve branches in the innervation of the abdominal muscles. In 2 cases nerve branches of the intercostal nerve to the diaphragm were found containing 15--25% motor axons.


[Histological investigations on adrenal cortex of sand rats (Psammomys obesus) during development of the diabetes mellitus (author's transl)].

The investigations were carried out on 20 sand rats (6 prediabetic, 6 diabetic and 8 normoglycemic animals). The cortices of adrenal glands were studied with histological methods. The thickness of the zona glomerulosa is in this 3 groups different. In the prediabetic group is the zona glomerulosa higher, in the diabetic group lower than the normoglycemic group. The relationship is 1.5 (normoglycemic group) : 2.9 (prediabetic group) : 0.8 (diabetic group). It is concluded that the zona glomerulosa in the prediabetic group is stimulated.


Histomorphological and histochemical researches on the digestive tract of the freshwater grass carp, Ctenopharyngodon idella (cypriniformes).

Ctenopharyngodon idella does not have a stomach, as is shown by the absence of gastric glands. The intestine is a simple coiled tube about twice the length of the body, having no valves and no ceca, and it is joined directly to the esophagus. The mucosa is fairly uniform in appearance, being thrown into folds which give it a mesh-like appearance. No multicellular glands can be detected in any part of the alimentary canal. Goblet cells are present: no differences are found in young specimens. Mucous in the goblet cells from young animals shows no differences in the various parts of the intestine. In the adult animals the mucous is markedly acidic in the first part of the intestine. In the young animals some migrant cells are present in the mucosa and in the connective tissue; these being more numerous in the fingerlings of 6--7 cm in length.


Structure of the esophagus in the adult opossum, Didelphis virginiana.

The structure of the esophagus has been studied in the adult opossum, Didelphis virginiana. A thickening of both layers of the muscularis externa occurs at the origin of the esophagus and may represent the upper esophageal sphincter; a massive expansion of the muscularis mucosae occurs in the region of the lower esophageal sphincter. The distribution of striated, mixed and smooth muscle in the muscularis externa differs in the inner and outer layers and elements of the myenteric plexus are found to occur even in the region of striated muscle; however, the ganglia of this plexus become much more prominent as smooth muscle makes its appearance. Esophageal glands are found in the lamina propria where they are confined to the 2 ends. They are especially prominent at the distal end where they are responsible for the formation of permanent transverse folds. Similar glands are found in the submucosa, scattered throughout the length of the esophagus but distally, in the region of the transverse folds, the submucous glands disappear. In both of these layers, the glands contain mucous, serous and myoepithelial cells.


Morphological events occuring in the seminiferous tubules of the Brazilian Nelore zebu associated with puberty.

The morphological events occurring in the Brazilian Nelore zebu testis from 3 to 18 months of age are described. Spermatozoa were seen only at 16--18 months of age indicating a considerable delay in the sexual development of the Nelore zebu when compared with taurine breeds.


[Increase functions of the type dW/dt = ktp-1(tEp--tp)q and their integrals (author's transl)].

After the investigations into 4 increase functions of organic growth a fifth ansatz should be added as dW/dt = ktp(tE--t)q with only the time t involved on the right side of the equation. In the course of researches about approximations the author has dealed with this type of functions, which can only be integrated within the limits t = 0 and t = tE leading to the Beta-function with W = E as a restricted result. Therefore the basic equation was thoroughly modified as to fit the type dW/dt = cf(t) df(t)/dt. Surprisingly the integration results in a growth function formally equal to the solution for the increase function dW/dt = ktp(E--W)n. Although the determination of the coefficients runs along other lines, the traditional example given in the preceding papers shows values so close to each other as to suppose genuine identity, which is finally proved. The fact, that seemingly quite different increase functions can lead to identical results must be given serious account: judging about increase functions should be taken as a rather delicate matter.


[Relationships between the height of intervertebral discs and the degree of lordosis of the cervical spine in children. A roentgenometric study (author's transl)].

On lateral roentgenograms of the cervical spine of 120 normal children between 3 and 14 years of age the ventral and dorsal height of all 5 intervertebral discs were measured and the "index of the intervertebral disc" was calculated. In addition, the "degree of lordosis" of the cervical spine was determined according to ISHIHARA (1964). Evaluation was in 3 age groups: 3 to 6, 7 to 10, 11 to 14 years; and the arithmetic mean and standard deviation were calculated for each group. All intervertebral discs are more or less "cuneiform" (ventrally higher than dorsally); they narrow from cranial to caudal. In children the degree of lordosis of the cervical spine shows a continuous decrease with advancing years. In all age groups girls show a lower degree of lordosis than boys. Statistically the differences of average values of the intervertebral-disc-index among the various shapes of the cervical spine in neutral position (straight, sublordotic, lordotic and hyperlordotic) are highly significant. By means of roentgenometric methods our examinations demonstrate that the lordotic curvature of the healthy cervical spine primarily depends on the cuneiform shape of intervertebral discs.


[Variations in the pathway of the inferior gluteal nerve (author's transl)].

In 17 out of 112 subjects examined, the inferior gluteal nerve leaves the pelvis through the piriformis and passes to the gluteus maximus. In 3 of the subjects the variation occurs bilaterally, and in 7 cases each it is found on either the right or the left side of the body alone. This variation occurs more often in women than in men. In all cases observed the common peroneal nerve also leaves the pelvis through the piriformis. Aside from the common peroneal nerve, the entire posterior femoral cutaneous nerve, or only its dorsal ramus, often runs alongside the inferior gluteal nerve through the "foramen intrapiriforme". The origin of this variations has to be discussed in connection with the specific embryological development of the piriformis.


[Doubling of the arteria testicularis sinistra with variations of origin and course--an embryological consideration (author's transl)].

During dissection of a human body anomalies in the origin and the course of the testicular artery have been observed. Besides a left testicular artery arching over the left renal vein there existed an additional testicular artery on the same side originating from the distal part of the left renal artery. The development of those anomalies is discussed under embryological aspects.


In vitro studies on the self-differentiating capacities of quail adenohypophysis epithelium.

Isolated epithelial rudiments of 3--4 days quail embryo adenohypophysis were cultivated in vitro. Differentiation of glandular cells occurred when culture conditions allowed the formation of explants characterized by the presence of a fibroblastic sheet and of an epithelial roof surrounding a central cavity. Differentiation did not occur when culture conditions did not allow the fibroblastic sheet to be established or resulted in the absence of a cavity. The importance of the explant structure in differentiation is also indicated by the location of glandular cells. In vitro they differentiate near the cavity derived from Rathke's pouch lumen while in situ they first appear at the periphery of the rudiment, near the basement membrane. The results of this study show that the adenohypophyseal primordium can differentiate without any mesenchymal influence. The observed differentiation seems to be correlated with fibroblast-secreted material, and this hypothesis is discussed.


The development of monoaminergic brainstem-spinal systems in the North American opossum.

Evidence is presented for an early appearance of monoaminergic neurites within the spinal cord of the developing opossum. They are present within the marginal zone before hindlimb movements begin (stage I) and they start to grow into the intermediate zone by the time hindlimb movements are first observed (stage II). Monoaminergic neurites grow first into the dorsolateral intermediate zone and the intermediolateral cell column where they can be found by the beginning of stage II. Shortly thereafter, fluorescent varicosities can be traced into the area dorsal to the central canal presumed to become lamina X. Fluorescent processes extend in to the ventral intermediate zone (ventral horn) somewhat later in development. Monoaminergic axons have grown into all of the areas they occupy in the adult animal, except for laminae I and II, by the time immature hindlimb movements can be altered by cutting all brainstem projections to the lumbosacral cord (stage III). Monoaminergic innervation of laminae I and II is the last to develope, but it is present by the time thoracic transection produces complete spinal shock.


A re-examination of mitotic activity in the early chick embryo.

As a result of extensive mitotic index analysis in colchicine-arrested chick embryos during gastrulation, it was ascertained that the primitive streak is a region of elevated mitotic index as compared to the surrounding tissue. Along the cephalo-caudal axis, the embryo displays two large peaks of mitotic index, one at the posterior end of the primitive streak and the other just anterior to Hensen's node. The length of the various phases of the mitotic period was determined in vitro by time-lapse filming, and the colchicine-arrested mitotic indices in vivo and in vitro were determined and compared for various regions. Some observations regarding the orientation of mitotic spindles and abnormal mitosis in vitro are also included, and the relevance of the above observations to early embryonic development is discussed.


Neurogenesis in the basal forebrain of the Chinese hamster (Cricetulus griseus). I. Time of neuron origin.

The time of neuron origin has been determined in the basal ganglia and related basal forebrain structures of the Chinese hamster with the aid of 3H-thymidine autoradiography. Large-celled structures like the globus pallidus, nucleus of the horizontal limb of the diagonal band of Broca as well as large cells in the rostral part of the substantia innominata, in the caudate-putamen-complex and in the olfactory tubercle arise early (E12--E16), whereas medium-sized and small cells in the basal forebrain have a persistent origin over a much longer period. Neuron formation in the basal forebrain persists decrementally until P4. A clear caudorostral spatiotemporal gradient as well as a distinct 'outside-in' gradient have been observed in the caudate-putamen-complex. Medium-sized neurons in the neostriatum and in the nucleus accumbens, generated simultaneously, are usually arranged in scattered clusters. The present data on time of neuron origin strongly support other evidence which points to the conclusion that the nucleus accumbens can be considered as a ventromedial extension of the caudate-putamen-complex.


The choroid plexus of the mature and aging rat: the choroidal epithelium.

The choroid plexus of mature and old rats has been examined by both scanning and transmission electron microscopy. It has been shown that the macrophages lying upon the ventricular surface of the choroid plexus have a close association with burr-like protrusions that extend from the apical surfaces of the choroidal epithelial cells. These protrusions have a dark cytoplasm filled with vesicles and tubules, and projecting from them are thin, shrunken microvilli. It is suggested that these protrusions are phagocytosed by the macrophages and that they are the source of some of the inclusions which become increasingly common within the cytoplasm of macrophages in older rats. The lateral surfaces of the choroidal epithelial cells have also been examined in the scanning electron microscope after exposure of the surfaces by dissection. In such preparations it is apparent that the elaborate interdigitations between adjacent cells are effected by irregular and vertically arranged folds confined to the basal portions of the lateral cell surfaces. Lastly, it has been shown that at the junction between the choroid plexus and the ependyma in the lateral ventricle, there are two modes of transition between the choroidal and ependymal epithelia. In one, typical choroidal and ependymal epithelial cells lie next to each other to produce a distinct and continuous bondary. In the other mode the boundary is also continuous, but there are modified ependymal cells present. These modified cells have short, relatively sparsely distributed microvilli and not more than one or two cilia.


Mandibular growth retardation in corticosteroid-treated juvenile mice.

Juvenile mice were treated for up to eight weeks with weekly doses of a synthetic analogue of cortisol:triamcinolone hexacetonide. The mandibular condylar cartilage was studied histologically and histochemically at regular intervals. Morphometric measurements were performed along the mandibular posterior vertical dimension (condylar process and ramus). By the second injection significant morphological changes were noted in the condylar cartilage, followed by retardation of bone growth. The most distinctive feature in the cartilage of triamcinolone-treated mice was a marked increase in the dimension of its mineralized zone concomitant with a significant increase in the number of hypertrophic chondrocytes. The role of condylar cartilage in mandibular growth is discussed.


Intraspinal non-neuronal cellular responses to peripheral nerve injury.

The accumulation of non-vascular, non-neuronal cells (designated herein as reactive cells) in association with perikarya of axotomized motor neurons has been described by many investigators. Recently Gilmore ('75) found that sciatic axotomy in immature rats resulted in the occurrence of reactive cells not only in the spinal ventral gray matter but also in the dorsal gray matter. To determine if the presence of these cells in the dorsal gray matter, a finding not reported by others, was related to the immaturity of the animal, sciatic axotomy was performed in rats ranging in age from 17 days to 16 months in the present study. Light microscopic evaluation of the spinal cords three or seven days post-operatively showed that the reactive cells occurred consistently in both dorsal and ventral gray matter irrespective of age. Transection of tibial nerve or the nerve to the medial head of the gastrocnemius muscle elicited a cellular response in both dorsal and ventral gray matter, although transection of the latter nerve resulted in a much less obvious response. Crushing of the sciatic nerve was followed by a response of reactive cells not qualitatively different from that noted following transection. Transection of the sural nerve, primarily a sensory nerve, resulted in the presence of reactive cells in dorsal gray matter but not in the environs of motor neurons in the ventral gray matter. These findings suggest that the reactive cells in the dorsal gray matter of the spinal cord are associated with altered central processes of dorsal root ganglion cells.


Effect of thyroparathyroidectomy (TPX) on the zona reticularis: a quantitative ultrastructural study.

Atrophy of zona reticularis cells was observed two weeks after surgical thyroparathyroidectomy (TPX). Quantitative morphological techniques for electron microscopy showed significant decreases in the volume of cytoplasm, nucleus, mitochondria, smooth endoplasmic reticulum and lipid droplets in the zona reticularis of TPX rats. In addition, many mitochnodria contained lipid droplets, some of which occupied virtually the entire matrix of mitochondria. The volume per cell of mitochondria with these inclusions increased significantly after TPX. The lipid droplets may well arise from cytoplasmic droplets by increased transport or reduced metabolism of cholesterol, or by direct incorporation of droplets into the mitochondrial matrix. The serum corticosterone level of TPX rats sacrificed under quiescent conditions did not differ significantly from that of controls. Hypothyroidism induced a significant increase in the volume of peroxisomes per cell in TPX animals which may be related to changes in lipid metabolism or transport.


Role of the left interventricular sulcus in formation of interventricular septum and crista supraventricularis in normal human cardiogenesis.

Serial sections of normal human embryos were studied and three-dimensional images reconstructed to determine the early development of the interventricular septum. The position of the interventricular septum is determined in stage 9 of normal development by the formation of the left interventricular sulcus. As a result of unknown properties of the cells of the myocardial layer, the left interventricular sulcus persists while the right disappears, producing the initial lateral asymmetry of the primary heart tube. By stage 14, the left interventricular sulcus forms a spiral which is continuous with the developing interventricular septum. The dorsal limb of the spiral passes to the right between the atrioventricular canal and the origin of the outflow tract, and is lost in the wall of the trabeculated right ventricle. It appears that this dorsal limb of the spiral is the precursor of part of the cirsta supraventricularis. The midportion of the sulcus, the bulboventricular groove, becomes the so-called fibrous continuity between the aortic and mitral valves. The ventral limb of the spiral passes caudally in the anterior interventricular groove and then dorsally and cranially toward the dorsal cushion of the atrioventricular canal. The ventral limb of the spiral is continuous with the crest of the muscular interventricular septum, which develops by apposition of tissue from the expanding right and left ventricles. From stage 14 to stage 19, the muscular interventricular septum, the atrioventricular endocardial cushions, and the ventricular end of the spiral ridges of the outflow tract appose and fuse. Subsequent formation of the membranous interventricular septum completes the physical separation of the right and left ventricles.


Early cytodifferentiation of human prostatic urethra and Leydig cells.

The ultrastructure of the urethral epithelium and mesenchyme of the 6- to 9-week-old human embryos was studied in order to reveal early morphological signs of prostatic development. The morphological changes of the urethral wall were correlated with the cytodifferentiation of the Leydig cells of the same embryos. Throughout the study the urethral epithelium had two or more layers of cuboidal cells. The ultrastructure of the cells was primitive and they did not achieve characteristics of the secretory prostatic cell. The surface cells had well developed apical junctions and slender cytoplasmic processes projecting into widened intercellular spaces appeared during the developmental period. The urethral mesenchyme showed the most salient changes. The mesenchymal cells adjacent to the urethral epithelium differentiated in the ninth week inot fibroblast-like cells with an elongated shape and cytoplasmic processes. Granular endoplamic reticulum appeared in the cytoplasm and collagen fibers were seen in the intercellular space. Mesenchymal cell processes contacting the continuous basal lamina under the epithelium were present. No direct epithelio-mesenchymal cellular contacts could be seen. The differentiation of the mesenchyme before the epithelial outgrowths that the mesenchyme has an essential role in the glandular development. Electron microscopic study of the Leydig cells showed that the amount of agranular endoplasmic reticulum increased considerably in the ninth week. This agrees with earlier biochemical findings on the capability of Leydig cells to produce androgens by this time. The temporal relationship between the cytodifferentiation of Leydig cells and the urethral wall is consistent with the idea that in the human, fetal androgens induce prostatic development.


The topography of rat submandibular gland parenchyma as observed with S.E.M.

The parenchymal components of rat submandibular gland were examined by scanning electron microscopy after removal of the stromal connective tissue by acid hydrolysis and/or enzymatic digestion. Secretory acini have polymorphous topographies but usually consist of three to five truncated lobes emanating from a common hilus. They have a mean volume of about 33,000 micrometers3. Myoepithelial cells are associated with the deeper acini of the gland where they cover congruent to 54% of the surface area of their allied acini. Each flattened myoepithelial cell has a central perikaryon that gives rise to four or five broad primary processes that bifurcate two or three times to produce a total complement of 20 to 40 terminal processes per cell, each 0.5 micrometer to 1.7 micrometers wide. The terminal processes of adjacent myoepithelial cells tend to slightly overlap and to attach to each other by desmosomes forming a network over adjacent acini. The components of the duct system are examined and each characterized by salient features as observed with the SEM.


Morphological study of the desert heteromyid kidney with emphasis on the genus Perognathus.

The renal morphology of three species of desert dwelling Perognathus rodents were compared to Dipodomys and two species of sympatric cricetid rodents. Perognathus has a highly adapted unipolar kidney capable of urine concentration up to 7,500 mOsm/KgH2O. Two major modifications were observed in these kidneys. (1) There is elongation of both the inner and outer medulla. When the thickness of the regions in P. penicillatus are factored by kidney weight it is found that the outer medulla is 3.8 and the inner medulla is 2.2 times greater in length than the extensively studied Dipodomys merriami. (2) There is great variance in glomerular size with approximately 20% of the glomeruli being very large and located in the juxta medullary region. These glomeruli are 1.5--1.6 times greater in diameter than the more numerous superficial glomeruli. These structural modifications are quantitated and the functional implications are discussed particularly in relation to urine concentrating ability in these desert inhabitants.


Ability of neural crest cells from the embryonic chick to differentiate into cartilage before their migration away from the neural tube.

Whether neural crest cells from the avian embryo are determined for chondrogenesis before they begin their migration away from the neural tube (i.e., before H. H. stages 8.5--9) was investigated by establishing neural folds from embryos of H. H. stages 5--11 either in organ culture, or as grafts to the chorioallantoic membranes of host embryos. Cartilage differentiated from neural folds taken from embryos of H. H. stages 5--7 but not from those taken from older embryos. This stage specific pattern was reversed when the tissue adjacent to the neural tube was grafted to the chorioallantoic membrane. Cartilage only formed from tissues isolated later than H. H. stage 8; i.e., when these adjacent tissues contain neural crest cells. We concluded that neural crest cells are determined for chondrogenesis while still in the neural tube and before their migration to the face and head. This is in contrast to the situation in the only other group which has been examined, the urodele amphibians.


Mitoses in peripheral pulmonary epithelium: the effect of colchicine.

Injury in the periphery of the lung was studied in rats given intratracheal trypsin. Mitotic figures were noted in the alveolar epithelium, and colchicine enhanced the yield. Of 65 mitotic figures examined in detail, 46 were present in the alveolar epithelium. Epithelial mitoses were confined to type II cells, many of which contained lamellar inclusions, abundant rough endoplasmic reticulum, and luminal microvilli. Mitoses were not seen in type I cells or in less well differentiated epithelial cells, but they were noted in occasional endothelial and interstitial cells. Colchicine-arrested type II cells were distinguished by radially disposed chromosomes surrounding pairs of centrioles and randomly oriented microtubules. In addition, many of these cells showed a pronounced cortical zone, devoid of microvilli, and others showed cytotoxic degenerative changes. These observations indicate that the alveolar epithelium is renewed exclusively by division of differentiated type II cells.


An autoradiographic and immunocytochemical study of the neonatal rat pituitary gland.

Two-day-old female rats were injected with 5 nmole/kg of 6,7-3H-11 beta-methoxy-17-ethylestradiol (R 2858 = moxestrol) and killed one hour later. The animals were decapitated and, the pituitary glands were removed, mounted on tissue holders and frozen in liquified propane. The tissue was then processed for autoradiography according to the thaw-mount technique. At the end of the exposure time, prior to photographic development, some of the tissue was fixed in 10% formalin and then photographically developed for autoradiography. The fixed tissue was subsequently stained immunocytochemically using antibodies to luteinizing hormone or prolactin. Between 10 and 15% of the cells of the pars distalis concentrated the synthetic estrogen or its metabolite. The immunocytochemical procedure revealed that both LH-gonadotrophs and lactotrophs concentrated the steroid. These studies along with earlier studies suggest that the neonatal rat pituitary contains only a small portion of the adult complement of estrogen receptors and that these receptors are dispersed across a number of cell types.


Surface area ratios. I. A stereological method for estimating average cell changes in membrane surface areas.

The study (i) describes a method for estimating relative changes in membrane surface areas as they occur in stereological "average cells," and (ii) considers the effect of the controls on these estimates. The results indicate that changes in five membranes compartments of pancreatic exocrine cells--produced by a secretagogue (carbomylcholine chloride)--were detected similarly when related to either an average cell surface (surface area ratio method) or to an average cell volume (method of Loud, '68). Changes, however, detected with surface densities, which relate these membrane compartments to 1 cm3 of exocrine cell cytoplasm or pancreas, were notably different from the first two estimates. This inconsistency could be explained by the fact that the surface densities were influenced not only by membrane changes within the exocrine cells, but also by changes in the number of these cells filling the cm3 of reference volume. Relating the data to an average cell reference--instead of 1 cm3--improved the accuracy of the estimates for changes in membrane surface areas by as much as several fold; the choice of controls had a similar several-fold effect on the results.


"Silver dust"--a tool to study growth interrelationships between bone, periosteum and muscle.

A cylinder of gelatin containing silver spongy granules was placed in and lay within the masseter muscle, the periosteum, and the mandible, and terminated in the medial pterygoid muscle of young (3 month-old) growing miniature pigs. On the basis of an animal sacrificed one week after placement of the cylinder, it was found that the suspending gelatin was removed by cellular activity. Nine months later the remaining animals were sacrificed. Periodic X-rays were taken during the course of the experiment. After sacrifice, the mandible and associated tissues were histologically examined. The results of this study suggest that the silver granules in the muscles maintained their location during growth; the silver granules in the mandible moved forward with mandibular growth. "Slippage" appeared to occur external to the fibrous layer of the periosteum; the site of movement was revealed by the trail of the silver granules. The described method should prove of value in studying the growth interrelationships between bone, periosteum, and muscle.


Chromatin substructure: an electron microscopic study of thin-sectioned chromatin subjected to sequential protein extraction and water swelling procedures.

Electron microscopic observations and measurements were made on thin-sectioned chromatin fibers and fibrils obtained from nuclei of mature chicken erythrocytes. The nuclei were isolated in low ionic strength gum arabic and octanol then extracted sequentially with (1) 0.14 M NaCl, (2) 0.25 N HCl, (3) buffer saturated phenol, (4) hot 5% SDS and 0.14 M 2-mercaptoethanol and, (5) 0.4 N NaOH. The amount of nuclear protein removed at each of the first four extraction steps was 1, 86, 3 and 11% of the total, respectively. Each extract was characterized by electrophoretic profiles. At each extraction the chromatin was fixed by adding large quantities of a mixture of equal volumes of sodium cacodylate buffered 8% (w/v) glutaraldehyde (pH 6.8) and 2% OsO4 (w/v), directly into (1) an aliquot of the chromatin in extraction fluid, and (2) an aliquot of the chromatin after water washing and swelling. Three size classes of chromatin structure were seen in thin sections prepared for high resolution transmission electron microscopy and stained with uranyl acetate and lead citrate. A thick fiber of about 25 + nm diameter was the predominant large fiber seen in freshly isolated nuclei or in nuclei after salt extraction. This 25 + nm fiber has a substructure consisting of 3.2-5.2 nm diameter fibrils. After water swelling of such freshly isolated or salt extracted nuclei a fiber of about 10 nm diameter was the predominant large fiber instead of the 25 nm diameter fiber. The HCl extraction step which is known to remove histones, caused the disappearance of both the 25 nm and the 10 nm fibers. High magnification (600,000 x) micrographs of the chromatin at all procedural steps, except the last NaOH step, reveal the fibril to be omnipresent. This fibril tends to decrease somewhat in diameter during the protein extraction steps to a 2.5 nm diameter fibril after the hot SDS extraction. A fibril of 2.5 nm diameter is expected of naked double helical DNA stained with a positive stain. The NaOH, which is known to denature DNA, completely destroyed the remaining fibril. We inerpret our results to indicate that the larger chromatin fiber seen in micrographs of thin-sectioned chromatin has a fibrillar substructure which probably represents a double coil of native DNA which may have a thin protein coating of its own. The latter fibril may in turn be wrapped around a hydrophobic histone domain, perhaps reflected in the 10 nm diameter fiber which is seen upon swelling of the chromatin. This 10 nm diameter fiber is thought to be further packaged by folding into the 25 + nm diameter chromatin fiber most frequently reported in thin sections of eukaryotic cell nuclei in situ.


Ultrastructure of the hepatic perisinusoidal cells in man and other mammalian species.

Perisinusoidal (P.S.) cells occurring in the spaces of Disse in the livers of normal cats, dogs, miniature pigs, albino rats, human adults and children were examined by electron microscopy. The ultrastructural details of the P.S. cells and their topographic relationships with hepatocytes, sinusoidal lining cells and reticulum fibers are described. Species differences between P.S. cells were primarily a dissimilarity in lipid content: the main ultrastructural features were the same in all species studied. The P.S. cells of the rat liver displayed only low endocytotic activity, and no phagosome formation following intravenous administration of horseradish peroxidase. The close topographic relationship of the P.S. cells with the intralobular reticulum fibers was reminiscent of the intimate connection between fibroblasts and collagen fibers, or, in cat liver, of the reticulum cell--reticulum fiber association seen in lymphoid organs. Fibroblasts were not found inside the hepatic lobules. These findings support the conclusion that the reticulum fibers of hepatic lobules are produced by perisinusoidal cells which, however, display also other functions.


Response of periodontal ligament cells to orthodontic force: ultrastructural identification of proliferating fibroblasts.

The morphologic response of periodontal ligament (PDL) cells in an area of tension created by orthodontic force has been assessed by transmission electron microscopy. Young adult male rats were sacrificed at 24, 48, 72, 96 and 120 hours following orthodontic stimulation. The earliest detectable response was the appearance of increased numbers of mitotic cells in the PDL at 24 hours post-stimulation. The most significant ultrastructural feature of these cells was the presence of intracellular vesicles containing collagen microfibrils. These vesicles were identical to profiles present in interphase PDL fibroblasts involved in collagen phagocytosis associated with turnover of the ligament. Between 48 and 120 hours the alveolar bone surface in the region examined was characterized by the presence of newly generated osteoblasts and active bone formation. Intracellular collagen was never observed in osteoblasts. These observations suggest that at least a portio- of the population of PDL cells which proliferate in response to orthodontic force represent functional ligament fibroblasts.


Mortality experience among anesthesiologists, 1954-1976.

To determine whether anesthesiologists, because of prolonged exposure to halothane or other inhalational anesthetics, might have higher death rates from all causes, from cancer, and from hepatic or renal disease than other physicians, the mortality rates of male and female members of the American Society of Anesthesiologists (ASA) for the period 1954 to 1976 were examined. Records of all physicians on ASA membership lists in 1954, 1959, 1967 and 1976 were obtained. All members, including life members, retired members and those who had stopped paying dues, were traced. Of the 637 deaths between 1954 and 1976 in male anesthesiologists, death certificates were obtained for 610. Mortality from all causes in those members who were accredited prior to 1960 was 84% of the expected death rate of all physicians. Among male members of record in 1967, it was 93% of the expected rate. There was no suggestion of an increased rate of cancer or hepatic or renal disease. There was a high suicide rate in members less than 55 years old. The overall mortality rate for the relatively small group (n = 66) of female anesthesiologists was 75 to 85% of that expected for all female physicians.


Myocardial metabolism and oxygenation in man awake and during halothane anesthesia.

Cardiac catheters were placed in seven healthy conscious patients so that aortic and left ventricular pressures (and the derivative), cardiac output (thermodilution) and myocardial blood flow (argon washin) could be measured. Blood was drawn for measurement of arterial blood-gas and arterial and coronary venous oxygen, glucose, lactate, pyruvate and fatty acid values. After induction of anesthesia by inhalation of halothane, the measurements were made during administration of low (0.70%) and high (1.54%) end-tidal halothane concentrations. Myocardial function decreased in a dose-related fashion without a change in heart rate. Myocardial blood flow and oxygen consumption were depressed in a similar manner. Myocardial oxygen extraction decreased and lactate did not change, suggesting that myocardial oxygenation was adequate. The heart rate-systolic blood pressure product correlated poorly with myocardial oxygen consumption. Systolic blood and the contractile performance index dP/dt/IP were better correlated with myocardial oxygen consumption, but the value of the coefficient was still low. Without significant changes in heart rate, systolic blood pressure is the best correlate of myocardial oxygen consumption in healthy man during the myocardial depression produced by halothane.