Stage I Melanoma of the Limbs. Immediate versus Delayed Node Dissection

553 patients with stage I malignant melanoma of the limbs entered a prospective randomized clinical trial carried out by the W.H.O. Collaborating Centres for Evaluation of Methods of Diagnosis and Treatment of Melanoma from September 1967 to January 1974. 286 patients were submitted to wide excision of primary and node dissection at the time as appearance of regional lymph node metastases and 267 to wide excision and immediate node dissection. Survival was identical in the 2 groups. Different subsets of patients were evaluated to assess whether some groups of patients may benefit from immediate node dissection. As regards sex, females and a significantly higher survival rate than males (p < 0.05), but results were not improved by immediate node dissection. Maximum diameter and elevation of primary melanoma were significantly related to survival but also in these cases immediate node dissection did not achieve better results. 63 patients had an excisional biopsy of their melanoma within 4 weeks before final treatment. This procedure did not worsen survival and also in this case immediate node dissection did not improve survival. 273 cases were classified according to histologic type: survival of superficial spreading and nodular melanoma was not different at a statistically significant level after the 2 treatment modalities. 325 cases were considered classifiable according to Clark's levels, out of these 165 were submitted to immediate node dissection. Neither level III nor level IV cases showed higher survival rate after immediate node dissection. Maximum tumor thickness according to Breslow was evaluated in 338 cases: 188 were submitted to wide excision and immediate node dissection. In no clusters of thickness did the enlarged surgical procedure achieve better results. The authors conclude that there is good evidence that in stage I melanoma of the extremities delayed dissection is as effective as the immediate one in the control of the disease if the patient can be kept under strict clinical control. Immediate node dissection is advisable if the quarterly follow-up is not guaranteed, at least for melanomas thicker than 2 mm.

Effect of Sonic Resin Composite Delivery on Void Formation Assessed by Micro-computed Tomography

OBJECTIVES

The aim of this study was to quantify the internal void volume formation in commercially available, resin composites inserted using conventional or sonic insertion methods, and analyzed using three-dimensional (3D) micro-computed tomography (μCT).

METHODS AND MATERIALS

Four resin composites were evaluated: one conventional (Herculite, Ultra, Kerr Corporation, Orange, CA, USA), one flowable bulk fill (SureFil SDR Flow, Dentsply International, York, PA, USA), and two packable bulk fill (SonicFill, Kerr Corporation, and Tetric EvoCeram Bulk Fill, Ivoclar Vivadent Inc, Schaan, Liechtenstein). Eight groups were evaluated according to each resin composite type and insertion method (conventional or sonic; n=5). Forty ABS 3D-printed cylindrical molds, 5.0 mm in diameter and 4.0 mm in depth, were fabricated. For the conventional resin composite, the mold was filled incrementally (two layers), while for bulk-fill resin composites, insertion was performed in a single increment. The sonic insertion method was performed using a specific handpiece (SonicFill Handpiece, Kerr Corporation). Resin composites were light cured using a multipeak light-emitting diode light-curing unit (VALO, Ultradent Products Inc, South Jordan, UT, USA) in its regular mode. Samples were evaluated by μCT, and data were imported into software (Amira, version 5.5.2, VSG, Burlington, MA, USA) for 3D reconstruction, from which the percentage of void volume was calculated. Data were analyzed using two-way analysis of variance and Tukey post hoc test at a preset alpha of 0.05.

RESULTS

The conventional insertion method resulted in reduced porosity, compared with sonic insertion, for SureFil SDR Flow and Tetric EvoCeram bulk fill. The sonic insertion method did not demonstrate any influence on void formation for Herculite Ultra or SonicFill.

CONCLUSION

Results suggest that the sonic insertion method might increase void formation during resin composite delivery, depending on restorative material brand.

Thoracolumbar fractures without neurological impairment: A review of diagnosis and treatment

An appropriate protocol and unified management of thoracolumbar fractures without neurological impairment has not been well defined.

This review attempts to elucidate some controversies regarding diagnostic tools, the ability to define the most appropriate treatment of classification systems and the evidence for conservative and surgical methods based on the recent literature.

Cite this article: Vilà-Canet G, García de Frutos A, Covaro A, Ubierna MT, Caceres E. Thoracolumbar fractures without neurological impairment: a review of diagnosis and treatment. EFORT Open Rev 2016;1:332-338. DOI: 10.1302/2058-5241.1.000029

Determination of ubiquitin fitness landscapes under different chemical stresses in a classroom setting

Ubiquitin is essential for eukaryotic life and varies in only 3 amino acid positions between yeast and humans. However, recent deep sequencing studies indicate that ubiquitin is highly tolerant to single mutations. We hypothesized that this tolerance would be reduced by chemically induced physiologic perturbations. To test this hypothesis, a class of first year UCSF graduate students employed deep mutational scanning to determine the fitness landscape of all possible single residue mutations in the presence of five different small molecule perturbations. These perturbations uncover 'shared sensitized positions' localized to areas around the hydrophobic patch and the C-terminus. In addition, we identified perturbation specific effects such as a sensitization of His68 in HU and a tolerance to mutation at Lys63 in DTT. Our data show how chemical stresses can reduce buffering effects in the ubiquitin proteasome system. Finally, this study demonstrates the potential of lab-based interdisciplinary graduate curriculum.

DOI:http://dx.doi.org/10.7554/eLife.15802.001

The ability of an organism to grow and reproduce, that is, it’s “fitness”, is determined by how its genes interact with the environment. Yeast is a model organism in which researchers can control the exact mutations present in the yeast’s genes (its genotype) and the conditions in which the yeast cells live (their environment). This allows researchers to measure how a yeast cell’s genotype and environment affect its fitness.

Ubiquitin is a protein that many organisms depend on to manage cell stress by acting as a tag that targets other proteins for degradation. Essential proteins such as ubiquitin often remain unchanged by mutation over long periods of time. As a result, these proteins evolve very slowly. Like all proteins, ubiquitin is built from a chain of amino acid molecules linked together, and the ubiquitin proteins of yeast and humans are made of almost identical sequences of amino acids.

Although ubiquitin has barely changed its sequence over evolution, previous studies have shown that – under normal growth conditions in the laboratory – most amino acids in ubiquitin can be mutated without any loss of cell fitness. This led Mavor et al. to hypothesize that treating the yeast cells with chemicals that cause cell stress might lead to amino acids in ubiquitin becoming more sensitive to mutation.

To test this idea, a class of graduate students at the University of California, San Francisco grew yeast cells with different ubiquitin mutations together, and with different chemicals that induce cell stress, and measured their growth rates. Sequencing the ubiquitin gene in the thousands of tested yeast cells revealed that three of the chemicals cause a shared set of amino acids in ubiquitin to become more sensitive to mutation.

This result suggests that these amino acids are important for the stress response, possibly by altering the ability of yeast cells to target certain proteins for degradation. Conversely, another chemical causes yeast to become more tolerant to changes in the ubiquitin sequence. The experiments also link changes in particular amino acids in ubiquitin to specific stress responses.

Mavor et al. show that many of ubquitin’s amino acids are sensitive to mutation under different stress conditions, while others can be mutated to form different amino acids without effecting fitness. By testing the effects of other chemicals, future experiments could further characterize how the yeast’s genotype and environment interact.

DOI:http://dx.doi.org/10.7554/eLife.15802.002

Responsive Cementing Material Prevents Annular Leaks in Gas Wells

In a traditionally cemented well, the integrity of the cement sheath surrounding the casing, and the bond between the cement and the formation or casing are essential components of hydraulic isolation. A well-cemented casing is designed to maintain hydraulic isolation throughout the productive life of the well and after abandonment. With advances in cementing technology, slurries have been designed that result in cement sheaths that can resist planned wellbore stresses without failure. Once the cement has set, however, the fixed set-cement properties do not address stresses that have not been planned for, and that may ultimately result in cement sheath failure.

This study considers the case of well construction as part of a new gas field exploration in Algeria. Wells drilled in this area have been prone to developing annular gas leaks in the weeks and months following cementing operations. To prevent the loss of isolation and reestablish hydraulic integrity in the event of cement failure, a new cement-based sealant was incorporated into the well construction plan. This reactive material responds to hydrocarbon leaks that occur because of fissures in the cement, debonding of cement from the formation or the development of a microannulus between the cement and the casing. These leaks trigger a self-healing response, sealing the leak path, and restoring well integrity. Using this sealant material has reduced the incidence and likelihood of leaking wells in an area where such problems are common, and eliminated the potential time and cost associated with leak remediation.

A porous PCL scaffold promotes the human chondrocytes redifferentiation and hyaline-specific extracellular matrix protein synthesis

The redifferentiation, proliferation, and hyaline-specific extracellular matrix (ECM) protein synthesis of chondrocytes cultured in a polycaprolactone (PCL) scaffold were analyzed. Gene expression of the type II collagen and aggrecan was assessed by real-time PCR in cells from PCL scaffolds, monolayer, and pellet cultures. The proliferative activity was assessed using Ki-67 immunodetection, and the chondrocytic differentiation was evaluated using S-100 immunodetection. The synthesis and deposition into scaffold pores of type II collagen and glycosaminoglycan were analyzed by immunohistochemistry and Alcian blue staining, respectively. All parameters were assessed throughout 28 days of cultures maintained in either fetal bovine serum-containing medium (FCM) or Insulin-Transferrin-Selenium-containing medium (ICM). Expression of the type II collagen gene was lower in FCM cultures than in ICM cultures for all culture systems (p < 0.05). Moreover, PCL scaffolds cultured in ICM were able to induce collagen gene expression more efficiently than pellet and monolayer cultures. Aggrecan gene expression did not vary significantly between mediums and three-dimensional system cultures, but in ICM cultures, the monolayer cultures had significantly higher levels of aggrecan gene expression than did either the PCL or pellet cultures. Chondrocytes cultured in PCL scaffolds or pellets with FCM did not proliferate to a great extent but did maintain their differentiated phenotype for 28 days. Levels of cartilage ECM protein synthesis and deposition into the scaffold pores were similar among PCL and pellet cultures grown in FCM and in ICM. In conclusion, chondrocytes seeded into PCL scaffolds, cultured in ICM, efficiently maintained their differentiated phenotype and were able to synthesize cartilage-specific ECM proteins.

The effect of bone graft geometry on spinal fusion vertebral stresses

Spinal fusion is a frequent surgical technique in which the success is uncertain due to post-operative changes in the biomechanics of the spine. Bone grafts are good candidates for disc and vertebra substitutes due to their similar bone properties and their good osteogenic properties. However, the effect of the anatomic harvest location of the bone graft on the load transfer is unknown. A physiologic three-dimensional (3D) finite element model of a lumbar spine was modified to model spinal fusion with a fixator and a bone graft. Bone grafts were taken either from the femur, the tibia, or from the fibula in a configuration of three or six fragments. The configurations were submitted to physiological loadings, and strain and stress distributions were calculated within the vertebrae, the fixator and the bone grafts. Quantitative differences were found from one type of bone graft to another. It was found that fibula bone grafts provided better stability by carrying a large part of the load. However, femoral and tibial bone grafts provided a more similar strain distribution within the vertebrae compared to the physiologic model. For tibial bone grafts, load transfer was found to be sensitive to the orientation used during the surgery. The use of a femoral bone graft to replace one vertebra and two intervertebral discs was found to give a better biomechanical function than using a tibial or fibula bone graft. This surgical technique is proposed to be beneficial in the case of severe spinal trauma providing good interface is obtained between the bone graft and the vertebrae.

Trophoblast origin of hCG isoforms: cytotrophoblasts are the primary source of choriocarcinoma-like hCG

We have previously demonstrated that a hyperglycosylated isoform of chorionic gonadotropin (hCG) (B152 hCG) is detected in the blood and urine in early pregnancy and is subsequently rapidly replaced by the hCG isoform (B109 hCG) characteristic of later pregnancy. In the current study we have extended our work on the origin of these isoforms. We have used a combination of in situ and in vitro approaches. Localization studies in placental tissues showed that monoclonal antibody B109 stained very specifically syncytiotrophoblast (STBs) from first and second trimester tissues. At term, STBs exhibited no B109 staining at all. Immunostaining with B152 antibody, that recognize the hyperglycosylated isoform of hCG, revealed only punctate staining of STBs in most villi of first trimester tissue. Both antibodies B109 and B152 failed to stain cytotrophoblasts (CTBs). To assess the functional relevance of these observations we analyzed conditioned media from purified CTBs using two immunometric assays, one of which (B152-B207*) has primary specificity for the hyperglycosylated, choriocarcinoma-like hCG and the other (B109-B108*) having primary specificity for the later pregnancy hCG isoform. Regardless of gestational age, isolated CTBs secreted predominantly B152 hCG isoform in contrast to placental villi (predominantly STBs), which released primarily the B109 hCG isoform. Isolated CTBs, however, failed to immunostain with both B109 and B152 antibodies. To resolve this contradiction, we cultured CTBs in the presence of brefeldin A, a drug known to block secretion by inhibiting protein translocation from the endoplasmic reticulum to the Golgi vesicles. Brefeldin A treated CTBs stained strongly with B109 and did not stain or stained weakly with B152 antibody. We assume that treatment with brefeldin A impaired glycosylation of beta subunit and consequently inhibited the production of hyperglycosylated form of hCG recognized by B152. In summary, our in vitro experiments indicate that both isoforms of hCG are produced by villus CTBs and that the dominant isoform is the one recognized by antibody B152. STBs produce primarily the less glycosylated B109 hCG isoform. This data suggests that at the beginning of pregnancy villus CTBs are the major source of the B152 hCG isoform. This finding is supported by our clinical data that show that the dominant hCG isoform in the blood and urine of pregnant women in the first 6 weeks of pregnancy is recognized by B152 (). The inversion of the B152/B109 ratio observed after 6-7 weeks of pregnancy can be explained by the reduction of number of villus CTBs and/or by maturation of STBs.

Protective role of human lactoferrin against invasion of Shigella flexneri M90T

Lactoferrin is an iron-binding protein found in human mucosal secretions such as milk. A variety of functions have been ascribed to this protein, it appears to contribute to antimicrobial host defense. Still its overall physiological role remains to be defined. We sought to study the role of recombinant human lactoferrin (rhLf) in Shigella infection. Invasion of epithelial cells is essential to the development of bacillary dysentery. Shigella flexneri 5 M90T, a virulent strain, was evaluated in the classic HeLa cell invasion model, in immunoblots, and by transmission electron microscopy, immunofluorescence, and deconvolved microscopy Bacteria not exposed to rhLf were used as controls. We found that rhLf decreased significantly the invasiveness of S. flexneri 5 M90T in a HeLa cell model. The immunoblot data showed that invasion plasmid antigen B (IpaB) was released from the bacteria during incubation with rhLf. Lactoferrin treatment did not directly dissociate the complex of IpaB and IpaC (IpaBC) once the complex had been formed. Furthermore, ferric iron had no effect on release of IpaB. Electron microscopy of rhLf-treated bacteria suggested a reduction in vacuolization of the HeLa cell cytoplasm and decreased number of bacteria within HeLa cells. At 40,000 x magnification the few rhLf-treated Shigella that invaded exhibited a dense ring completely surrounding them. Immunofluorescence and deconvolved microscopy suggested that rhLf-treated bacteria were completely surrounded by a thick layer of actin. The fact that two cell surface functions (invasion and actin-mediated movement) were deranged suggests that rhLf disrupts the integrity of the bacterial outer membrane in which virulence proteins are anchored. The mechanism by which rhLf impairs Shigella invasiveness may be relevant to other enteropathogens that share similar virulence strategies.

Vaginal bleeding patterns among rural highland Bolivian women: relationship to fecundity and fetal loss

Among the most common reasons given for discontinued use of some contraceptive methods is a disturbance in the menstrual cycle, particularly changes in vaginal bleeding. Work to date suggests marked populational variation in menses duration, but few data have been collected from South America. This longitudinal study of non-contracepting Aymara women (n = 189 providing 837 non-truncated bleeding episodes) identified conceptions and fetal loss via urine tests for human chorionic gonadotropin and classified episodes accordingly to test the hypotheses that (a) vaginal bleeding patterns differ between lactating and non-lactating women, (b) duration of vaginal bleeding accompanying fetal loss differs from that of menstruation, (c) menses preceding a conception are longer than those not followed by a conception. Compared to published values, mean menses duration (3.5 days) in these women was relatively short. Menses duration was not significantly correlated with current age, age at menarche or first birth, parity, time postpartum, or menstrual segment length. Mean menses duration (not preceding a conception) was comparable for lactating and non-lactating women. Mean duration of fetal loss bleeding did not differ from that of menses. Pre-conception episodes were significantly longer than those not followed by conception. Thus, because the rate of conceptions was twice as great among lactating than non-lactating women, the mean duration of all menses (irrespective of conception) was significantly longer in lactating women. Bolivian, and perhaps other South American, women may be particularly disinclined to accept contraceptives (e.g., intrauterine devices) that modify an otherwise relatively brief menses duration. Therefore, a wide variety of contraceptive choices accompanied by population-specific informed counseling is essential. In addition, these findings suggest that studies of fecundability limited to non-lactating women may be biased toward those of relatively lower fecundity and that menses duration may be predictive of risk for some cancers.

TP53 polymorphism, HPV infection, and risk of cervical cancer

The role of a polymorphism at position 72 of the tumor suppressor gene TP53 in the development of cervical cancer is not well established. The arginine variant of the p53 protein could be more susceptible to degradation by human papillomavirus (HPV) E6 protein than the protein containing proline. Recent studies show controversial results. We investigated a possible association between TP53 polymorphism and cervical cancer in a Peruvian population with high prevalence of HPV infection. HPV status and TP53 polymorphism were determined for 119 cases of invasive cervical cancer and 127 control women from Peru. HPV infection was detected by PCR of cervical cells or tumor biopsies. For determination of TP53 polymorphism, exon 4 of the TP53 gene was amplified by PCR, and DNA was subsequently subjected to restriction enzyme digest. Associations between TP53 polymorphism, HPV infection, and cervical cancer were assessed using logistic regression. Women homozygotes for arginine had a 2.2-fold increased risk (95% confidence interval: 0.6-7.6) for cervical cancer. The odds ratio for women heterozygotes for Arg/Pro was 3.5 (95% confidence interval: 0.9-14). Similarly increased risks were found when restricting analysis to HPV-positive women only. The distribution of TP53 genotypes in this Peruvian population was comparable with that found in Caucasians. Our results cannot rule out an association between the TP53 polymorphism at codon 72, HPV infection, and the etiology of cervical cancer.

HPV types and cofactors causing cervical cancer in Peru

We conducted a hospital-based case-control study in Peru of 198 women with histologically confirmed cervical cancer (173 squamous cell carcinomas and 25 cases of adenocarcinoma/adenosquamous carcinoma) and 196 control women. Information on risk factors was obtained by personal interview. Using PCR-based assays on exfoliated cervical cells and biopsy specimens, HPV DNA was detected in 95.3% of women with squamous cell carcinoma and in 92.0% of women with adenocarcinoma/adenosquamous carcinoma compared with 17.7% in control women. The age-adjusted odds ratio was 116.0 (95% Cl = 48.6-276.0) for squamous cell carcinoma and 51.4 (95% Cl = 11.4-232.0) for adenocarcinoma/adenosquamous carcinoma. The commonest types in women with cervical cancer were HPV 16, 18, 31, 52 and 35. The association with the various HPV types was equally strong for the two most common types (HPV 16 and 18) as for the other less common types. In addition to HPV, long-term use of oral contraceptives and smoking were associated with an increased risk. HPV is the main cause of both squamous cell carcinoma and adenocarcinoma in Peruvian women.

Plasma membrane-associated pY397FAK is a marker of cytotrophoblast invasion in vivo and in vitro

During human pregnancy specialized placental cells of fetal origin, termed cytotrophoblasts, invade the uterus and its blood vessels. This tumor-like process anchors the conceptus to the mother and diverts the flow of uterine blood to the placenta. Previously, we showed that the expression of molecules with important functional roles, including a number of extracellular matrix integrin receptors, is precisely modulated during cytotrophoblast invasion in situ. Here we exploited this observation to study the role of the focal adhesion kinase (FAK), which transduces signals from the extracellular matrix and recruits additional signaling proteins to focal adhesions. Immunolocalization studies on tissue sections showed that FAK is expressed by cytotrophoblasts in all stages of differentiation. Because extracellular matrix-induced integrin clustering results in FAK (auto)phosphorylation on tyrosine 397 (Y397FAK), we also localized this form of the molecule. Immunolocalization experiments detected Y397FAK in a subset of cytotrophoblasts near the surface of the uterine wall. To assess the functional relevance of this observation, we used an adenovirus strategy to inhibit cytotrophoblast expression of FAK as the cells differentiated along the invasive pathway in vitro. Compared to control cells transduced with a wild-type virus, cytotrophoblasts that expressed antisense FAK exhibited a striking reduction in their ability to invade an extracellular matrix substrate. When cytotrophoblast differentiation was compromised (hypoxia in vitro, preeclampsia in vivo), Y397FAK levels associated with the plasma membrane were strikingly lower, although total FAK levels did not change. Together our results suggest that (auto)phosphorylation of Y397 on FAK is a critical component of the signaling pathway that mediates cytotrophoblast migration/invasion.

Does hypoxia impair ovarian function in Bolivian women indigenous to high altitude?

Fertility appears to be reduced in at least some high altitude populations relative to their counterparts at lower elevations. Inferring from the difficulties with reproduction of newcomers to high altitude and from animal experiments, it has been hypothesized that this apparent reduction is the result of hypoxia acting to reduce fecundity and/or increase fetal loss. In humans, however, several behavioral as well as biological factors may affect fertility levels. These many factors have been organized by demographers into a framework of seven proximate determinants that includes fecundability (the monthly probability of conception) of which successful ovulation is one component. To test whether ovarian function is impaired in women indigenous to high altitude, we measured salivary progesterone (P) in a sample (n = 20) of Quechua women (aged 19-42 years) residing at 3,100 m. It was found that mean luteal P = 179 pmol/L and mean midluteal P = 243 pmol/L, levels that fall about midway in the range of known values for several populations and are higher than some lower altitude populations. These findings suggest that hypoxia does not appear to significantly impair ovarian function in those with lifelong residence at high altitude. There are, however, several factors common to many high altitude populations that may act to reduce fecundability and fertility including intercourse patterns (affected by marriage and migration practices), prolonged lactation, dietary insufficiency, and hard labor.

Menstrual patterns and fecundity among non-lactating and lactating cycling women in rural highland Bolivia: implications for contraceptive choice

Choosing an appropriate contraceptive method, particularly one based on fertility awareness, depends in part upon the degree of a woman's cycling regularity. However, while the suppressive effect of lactation on ovarian function is well established, the potential influence of continued breastfeeding on menstrual patterns once post-partum cycling has resumed is largely unexamined. This longitudinal study in a population of non-contracepting Aymara women (n = 191 providing 665 non-truncated menstrual segments) identified conceptions and fetal loss via urine tests for hCG and classified segments accordingly to test the hypotheses that (1) cycles in lactating women are significantly different in length and regularity from those of non-lactating women, and (2) cycles in women living at high altitude are significantly different in length and regularity from those at lower altitudes. Analyses found that segments are significantly longer and regularity tends to be less common among lactating than non-lactating women; however, the rate of conception is twice as great among the former than the latter, and the distribution of conception outcomes does not differ between the two groups. Menstrual regularity is not the norm in this population, even among those who are not currently breastfeeding. High altitude per se does not appear to influence menstrual cycling as both regularity and segment length are comparable to other populations, hence women indigenous to high altitude are suitable candidates for a wide variety of contraceptive choices. In addition, these findings suggest that studies of fecundability limited to non-lactating women may be biased towards those of relatively lower fecundity.

Effect of developmental and ancestral high-altitude exposure on VO(2)peak of Andean and European/North American natives

Peak oxygen consumption (VO(2)peak) was measured in 150 adult males (18-35 years old) in Bolivia, using a complete migrant study design to partition developmental from ancestral (genetic) effects of high-altitude (HA) exposure. High-altitude natives (HANs, Aymara/Quechua ancestry, n = 75) and low-altitude natives (LANs, European/North American ancestry, n = 75) were studied at high altitude (3,600-3,850 m) and near sea level (420 m). HAN and LAN migrant groups to a nonnative environment were classified as: multigeneration migrants, born and raised in a nonnative environment; child migrants who migrated to the nonnative environment during the period of growth and development (0-18 years old); and adult migrants who migrated after 18 years of age. Variability in VO(2)peak due to high-altitude adaptation was modeled by covariance analysis, adjusting for fat-free mass and physical activity (training) differences between groups. A trend for increased VO(2)peak with increasing developmental high-altitude exposure in migrant groups did not reach statistical significance, but low statistical power may have limited the ability to detect this effect. HANs and LANs born, raised, and tested at high altitude had similar VO(2)peak values, indicating no genetic effect, or an effect much smaller than that reported previously in the literature. There was no functional correlation between forced vital capacity and VO(2)peak, within or across groups. These results do not support the hypothesis that Andean HANs have been selected to express a greater physical work capacity in hypoxia.

Lagochilascaris minor in a patient from the Colombian amazon: a case report

A chronic infection (10 years) by Lagochilascaris minor is described in a woman from the amazon region of Colombia. This is the third case of infection by this parasite that has been described so far in Colombia, and only the first one in a person coming from the Colombian Amazon region.

Fluid regulatory hormone response to exercise after coca-induced body fluid shifts

To determine the effect of coca chewing on heart rate (HR), mean arterial blood pressure (MAP), and plasma volume and their relationship with the hormones regulating cardiovascular and body fluid homeostasis, 16 male volunteers were examined at rest and during 1 h of cycle exercise at approximately 75% of their peak oxygen uptake in two trials separated by 1 mo. One trial was performed after the subjects chewed a sugar-free chewing gum (Coca- trial), whereas the other was done after the subjects chewed 15 g of coca leaves (Coca+), with the order of the Coca- and Coca+ trials being randomized. Blood samples were taken at rest, before (R1) and after 1-h chewing (R2), and during the 5th, 15th, 30th, and 60th min of exercise. They were analyzed for hematocrit, hemoglobin concentration, red blood cell count, plasma proteins, and for the fluid regulatory hormones, including plasma catecholamines [norepinephrine (NE) and epinephrine], renin, arginine vasopressin, and the atrial natriuretic peptide (ANP). During the control trial (Coca-), from R1 to R2, there was no significant change in hematologic, hormonal, and cardiovascular status except for a small increase in plasma NE. In contrast, it can be calculated that coca chewing at rest induced a significant hemoconcentration (-3.8 +/- 1. 3% in blood and -7.0 +/- 0.7% in plasma volume), increased NE and MAP, and reduced plasma ANP. Chewing coca before exercise reduced the body fluid shifts but enhanced HR response during exercise. These effects were not accompanied by changes in NE, epinephrine, renin, and arginine vasopressin plasma levels. In contrast, plasma ANP response to exercise was lower during the Coca+ trial, suggesting that central cardiac filling was reduced by coca use. It is likely that the reduction in body fluid volumes is a major contributing factor to the higher HR at any given time of exercise after coca chewing.

Differential effects of ventilatory stimulation by sex hormones and almitrine on hypoxic erythrocytosis

In the absence of pulmonary disease, hypoventilation is considered to be the primary cause of Chronic Mountain Sickness, and there is some reason to believe that chronic administration of respiratory analeptics could be useful for treatment of this disease. The present study was intended to define comparatively the influence of two potent ventilatory stimulants, namely a combination of progesterone and estrogen and the pharmacological agent almitrine, on catecholaminergic structures implicated in the chemoreflex pathway and on hypoxia-induced polycythemia. Three groups of young male rats born and living at high altitude (3 600 m) were examined: untreated animals (n = 25), rats given ovarian steroids (progesterone plus 17beta-estradiol, n = 25) or almitrine (n = 25) for 6 weeks until sacrifice. Ovarian steroids or almitrine had pronounced neurochemical effects on the afferent chemoreflex circuitry. Both treatments inhibited norepinephrine (NE) and dopamine (DA) turnover in the carotid body, but central processing of chemosensory inputs differed between the two respiratory drugs. Ovarian steroids inhibited noradrenergic activity in the projection area of the chemosensory nerve fibers within the caudal portion (A2C) of the nucleus tractus solitarius (NTS). In contrast, almitrine stimulated neurochemical activity of other brainstem noradrenergic cell groups involved in cardiorespiratory control, i.e. , the rostral portion (A2R) of the NTS, the nucleus reticularis lateralis (A1), the nucleus olivaris superior (A5) and the locus ceruleus (A6). Although both treatments increased chemoreflex drive and ventilation, only sex hormones decreased erythropoietin (EPO) levels and the degree of polycythemia. These results suggest that stimulation of ventilation through activation of peripheral arterial chemoreceptors activation alone is not sufficient for reducing EPO levels and polycythemia. The better efficiency of female sex hormone treatment as compared to almitrine could be related either to the central effects of progesterone and estrogen and/or to the impact of these hormones on erythropoiesis at the kidney/bone marrow level.

Influence of gender and endogenous sex steroids on catecholaminergic structures involved in physiological adaptation to hypoxia

Mechanisms underlying sex-related differences in adaptation to high altitude were investigated by assessing the turnover of dopamine and noradrenaline in structures of the chemoafferent pathway, i.e. carotid body and brainstem noradrenergic cell groups (A1, A5, A6, A2 to which chemosensory fibres project). The influence of gender was assessed in male and female rats reared at an altitude of 3600 m, whereas the influence of endogenous sex hormones was evaluated by castration. Haematocrit, red blood cell count and plasma erythropoietin levels were lower in females than in males (-5%, -15%, -53%, respectively). Dopamine and noradrenaline turnover were higher in female structures (carotid body: +51%; A2: +140%; A1: +54%; A5: +27%). Dopamine and noradrenaline turnover in carotid body and brainstem cell groups were differently affected by castration, i. e. enhanced by orchidectomy (carotid body: +134%; A2: +120%; A1: +69%; A5: +67%) but inhibited by ovariectomy (carotid body: -33%; A2: -92%). Orchidectomy elicited a reduction in haematocrit (-10%), haemoglobin concentration (-8%) and red blood cell count (-24%), whereas haematological status remained unaltered after ovariectomy. Therefore, both gender and endogenous sex steroids may control catecholamine activity differently in structures involved in the chemoafferent pathway, thus providing a neurochemical basis for sex-related differences in adaptation to hypoxia.

Body fluid homeostasis and cardiovascular adjustments during submaximal exercise: influence of chewing coca leaves

The present study was undertaken to determine the haematological and cardiovascular status, at rest and during prolonged (1h) submaximal exercise (approximately 70% of peak oxygen uptake) in a group (n = 12) of chronic coca users after chewing approximately 50 g of coca leaves. The results were compared to those obtained in a group (n = 12) of nonchewers. At rest, coca chewing was accompanied by a significant increase in heart rate [from 60 (SEM 4) TO 76 (SEM 3) beats.min-1], in haematocrit [from 53.2 (SEM 1.2) to 55.6 (SEM 1.1)%] in haemoglobin concentration, and plasma noradrenaline concentration [from 2.8 (SEM 0.4) to 5.0 (SEM 0.5) mumol.l-1]. It was calculated that coca chewing for 1 h resulted in a significant decrease in blood [-4.3 (SEM 2.2)%] and plasma [-8.7 (SEM 1.2)%] volume. During submaximal exercise, coca chewers displayed a significantly higher heart rate and mean arterial blood pressure. The exercise-induced haemoconcentration was blunted in coca chewers compared to nonchewers. It was concluded that the coca-induced fluid shift observed at rest in these coca chewers was not cumulative with that of exercise, and that the hypovolaemia induced by coca chewing at rest compromised circulatory adjustments during exercise.

Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers

To determine the effects of acute coca use on the hormonal and metabolic responses to exercise, 12 healthy nonhabitual coca users were submitted twice to steady-state exercise (approximately 75% maximal O2 uptake). On one occasion, they were asked to chew 15 g of coca leaves 1 h before exercise, whereas on the other occasion, exercise was performed after 1 h of chewing a sugar-free chewing gum. Plasma epinephrine, norepinephrine, insulin, glucagon, and metabolites (glucose, lactate, glycerol, and free fatty acids) were determined at rest before and after coca chewing and during the 5th, 15th, 30th, and 60th min of exercise. Simultaneously to these determinations, cardiorespiratory variables (heart rate, mean arterial blood pressure, oxygen uptake, and respiratory gas exchange ratio) were also measured. At rest, coca chewing had no effect on plasma hormonal and metabolic levels except for a significantly reduced insulin concentration. During exercise, the oxygen uptake, heart rate, and respiratory gas exchange ratio were significantly increased in the coca-chewing trial compared with the control (gum-chewing) test. The exercise-induced drop in plasma glucose and insulin was prevented by prior coca chewing. These results contrast with previous data obtained in chronic coca users who display during prolonged submaximal exercise an exaggerated plasma sympathetic response, an enhanced availability and utilization of fat (R. Favier, E. Caceres, H. Koubi, B. Sempore, M. Sauvain, and H. Spielvogel. J. Appl. Physiol. 80: 650-655, 1996). We conclude that, whereas coca chewing might affect glucose homeostasis during exercise, none of the physiological data provided by this study would suggest that acute coca chewing in nonhabitual users could enhance tolerance to exercise.

Hormonal and metabolic adjustments during exercise in hypoxia or normoxia in highland natives

In sea-level natives, exposure to hypoxia for a few weeks is characterized by an increased dependence on blood glucose and a decreased reliance on lactate for energy metabolism during exercise. These metabolic adjustments have been attributed to behavioral changes in the sympathoadrenergic and pancreatic systems. The aim of this study was to test the hypothesis of a reduced sympathoadrenergic activation and subsequent metabolic changes when high-altitude natives are acutely exposed to normoxia. Young Andean natives performed incremental exercise to exhaustion during hypoxia (arterial PO2 55.1 +/- 1.1 Torr) or during acute normoxia (arterial PO2 78.7 +/- 1.7 Torr). As a whole, oxygen uptake was increased in normoxia compared with hypoxia during graded exercise. This finding is not related to a decrease in anaerobic metabolism but rather is interpreted as a consequence of a shift in substrate utilization during exercise (increased contribution of fat as assessed by a reduction in the respiratory exchange ratio). These metabolic changes are not accompanied by modifications of glucoregulatory hormones (catecholamines, insulin, and glucagon). In particular, the exercise-induced catecholamine secretion was similar in chronic hypoxia and acute normoxia. As a consequence, blood lactate accumulation during incremental exercise was similar in both conditions. It is concluded that high-altitude natives do not display any sign of a greater sympathoadrenergic activation during chronic hypoxia and that the exercise-induced hormonal changes remained unaffected by acute inhalation of a normoxic gas mixture.

Effects of coca chewing on hormonal and metabolic responses during prolonged submaximal exercise

The effects of coca chewing on prolonged submaximal exercise responses were investigated in chronic coca chewers and compared with a group of nonchewers. At rest, coca chewing during a 1-h period was followed by a significant increase in blood glucose, free fatty acid, and norepinephrine concentrations and a significant reduction in insulin plasma level. During prolonged (1-h) submaximal (65-70% peak O2 uptake) exercise, chewers displayed a significantly greater adrenergic activation (as evidenced by a higher level of plasma epinephrine) and an increased use of fat (as evidenced by a lower respiratory exchange ratio). The gradual increase in oxygen uptake (O2 drift) commonly observed during prolonged exercise was blunted in coca chewers. This blunting in O2 drift is not related to coca-induced changes in ventilatory or lactate responses to exercise but could possible be related to an enhanced glucose utilization by chewers during the late phase of exercise. The present results provide experimental evidence of the physiological effects of coca chewing that could explain the better ability of coca users to sustain strenuous work for an extended period of time.

Effects of coca chewing on metabolic and hormonal changes during graded incremental exercise to maximum

We examined the effects of 1 h of coca chewing on metabolic and hormonal responses during incremental exercise to exhaustion in traditional coca chewers (C; n = 8), and the results were compared with a group of nonchewers (n = 13). For 1 h, C chewed approximately 12 g of coca leaves that resulted in the apparition of cocaine in blood that reached 72 +/- 9 ng/ml. In resting conditions, even though sympathoadrenergic activity (as assessed by norepinephrine and epinephrine plasma levels) was similar in both groups, C displayed a higher level of plasma free fatty acids. Oxygen uptake measured at exhaustion and delta work efficiency during exercise were similar in both groups. During the incremental exercise, C displayed a significantly lower arterial oxygen saturation that cannot be explained by a reduced ventilatory response after coca chewing. In fact, even at maximal exercise, both ventilatory output and ventilatory equivalent were higher in C compared with nonchewers. It is concluded that the beneficial effects of coca chewing on exercise tolerance reported frequently by traditional coca users is not related to either an improved maximal exercise capacity or an increased work efficiency. However, during incremental exercise, coca chewing appeared to result in an increased free fatty acid availability that could be beneficial for prolonged submaximal exercise.

Training in hypoxia vs. training in normoxia in high-altitude natives

To determine the interactions between endurance training and hypoxia on maximal exercise performance, we performed a study on sedentary high-altitude natives who were trained in normoxia at the same relative (n = 10) or at the same absolute (n = 10) intensity of work as hypoxia-trained subjects (n = 10). The training-induced improvement of maximal oxygen uptake (VO2max) in hypoxia-trained subjects was similar to that obtained in normoxia-trained sea-level natives submitted to the same training protocol (H. Hoppeler, H. Howald, K. Conley, S. L. Lindstedt, H. Claassen, P. Vock, and E. W. Weibel. J. Appl. Physiol. 59: 320-327, 1985). Training at the same absolute work intensity in the presence of increased oxygen delivery failed to provide a further increase in VO2max. VO2max was not improved to a greater extent by simultaneously increasing absolute work intensity and O2 delivery during the training sessions. In addition, training in normoxia is accompanied by an increased blood lactate accumulation during maximal exercise, leading to greater drops in arterial pH, bicarbonate concentration, and base excess. We conclude that, in high-altitude natives, 1) training at altitude does not provide any advantage over training at sea level for maximal aerobic capacity, whether assessed in chronic hypoxia or in acute normoxia; 2) VO2max improvement with training cannot be further enhanced by increasing O2 availability alone or in combination with an increased work intensity during the exercising sessions; and 3) training in normoxia in these subjects results in a reduced buffer capacity.

Total lung capacity in young highlanders of Aymara ancestry

Total lung capacity (TLC) and its components, including residual volume (RV) and vital capacity (VC), are described in a sample of 164 male and 143 female youths of Aymara ancestry (10.0-19.9 years) who were born and raised at high altitudes (> 2,500 m) and who were residing in La Paz, Bolivia (average altitude of about 3,600 m). The hypothesis was tested that the enhanced lung volumes of adult highlanders are attained during the period of growth and development. As found in adult male highlanders, TLC in young highlanders was significantly larger than in lowlanders of the same sex and body size, primarily as a result of increases in RV and secondarily through increases in VC. In addition, estimates of the magnitude of the effect of chronic hypobaric hypoxia on all of the measures of pulmonary function, including TLC, RV, and VC, were positively related to age. This finding suggests that growth and development at high altitude is associated with a constant increase in TLC and other measures of pulmonary function relative to those of lowlanders, a finding which is consistent with the expectations of the developmental adaptation hypothesis. However, although these relationships were statistically significant in males, they were not significant in females. Thus, although the magnitude of the estimated effects of chronic hypobaric hypoxia on TLC, RV, and VC were similar in males and females, the developmental pattern by which these enhanced volumes are achieved may differ between sexes.

Effect of chronic hypoxia and socioeconomic status on the maximal oxygen uptake of 10- to 12-year-old Bolivian boys

The aim of this study was to analyze the effect of altitude and socioeconomic status on the maximal oxygen uptake (VO2max) of prepubertal Bolivian boys. The subjects were 143 prepubertal boys (10 to 11.5 years old) living in La Paz (altitude 3600 m, n = 67) and Santa Cruz de la Sierra (altitude 420m, n = 76). At high altitude, 23 boys were from a high socioeconomic status (HAHSES) and 44 from a low socioeconomic background (HALSES). At low altitude, 29 boys were from a high socioeconomic level (LAHSES) and 47 from a low socioeconomic background (LALSES). Anthropometric characteristics were determined in order to assess the physical growth of the boys. The VO2max was determined from a progressive maximal exercise (direct method). The subjects performed this test using the same cycle ergometer at both high and low altitudes. For the overall anthropometric parameters, there was no significant difference between highland and lowland boys of the same socioeconomic status. However, regardless of altitude, boys from a low socioeconomic background were 2 years behind those from a high socioeconomic background. There was no significant difference for VO2max between boys from high and low socioeconomic backgrounds at HA (HAHSES: 37.2 +/- 5.6; HALSES: 38.9 +/- 6.4 ml.min-1.kg-1 body weight) and at LA (LAHSES: 42.6 +/- 5.4; LALSES: 43.1 +/- 4.9 ml.min-1.kg-1 body weight). The VO2max of highland boys was, on average, 11% lower than that of lowland boys. It appears, therefore, that a difference in socioeconomic status has no effect on the VO2max (ml.min-1.kg-1) of prepubertal children at low altitude as well as the altitude of 3600m.

[Financing research in Chile in biotechnology and other areas related to the productive sector]

This study describes the financial support for research in Chile in different areas related to the productive sector including biotechnology. Four different sources which help research in the country through competitive research grants were analysed. These include: FONDECYT (National Fund for Research and Technology), Fondo de Desarrollo Productivo de CORFO (Fund for Productive Development), Fondo de Investigaciones Agropecuarias (Fund for Research in Agriculture and Livestock) and the IV Program for Technical Cooperation between the Chilean Government and UNDP. Biotechnology appears as one of the areas related to the productive sector having an important number of projects approved with a substantial financial support. Based in a survey, recommendations are made to improve the relationship between the productive and academic sector in biotechnology and other areas.

Distribution and etiology of leishmaniasis in Colombia

A total of 340 Leishmania strains, isolated from humans, animals, and sand flies from various regions of Colombia, were examined by isozyme electrophoresis. Seven different Leishmania species were identified. Leishmania panamensis and L. braziliensis were the most common, representing 53.8% and 30.3% of the total, respectively. Isolation rates of the other species were as follows: L. chagasi, 9.4%; L. guyanensis, 2.6%; L. amazonensis, 1.8%; L. mexicana, 0.8%; and a new species requiring additional study, 1.2%. Statistical analyses of representative L. panamensis and L. braziliensis isolates indicated that the populations of these 2 species are genetically very similar. L. panamensis may have a continuous distribution in Colombia west of the eastern Andes Mountains and L. braziliensis may have a continuous distribution east of the western Andes Mountains. Information is given on disease manifestations of the parasites in human hosts and on isolation records from sand flies and animals.

Incidence of regional lymph node metastasis in operable osteogenic sarcoma

Records of 182 consecutive patients with the diagnosis of operable osteogenic sarcoma, treated between 1954 through 1980 by the Breast, Bone and Mixed Tumors Department of the Instituto Nacional de Enfermedades Neoplasicas (Lima, Peru), were reviewed to study the incidence of regional lymph node metastases in this disease. All the patients included in this study had radical surgery, which means the complete resection of the bone where the tumor is located, including the proximal joint, which permitted excision of the regional lymph nodes. Nineteen patients (10.4%) had evidence of sarcoma metastatic to draining lymph nodes. A comprehensive analysis of the literature shows that the incidence of metastasis to the lymph nodes in this study, is higher than those cited in a review of the literature, probably due to the policy in the management of osteogenic sarcoma in our institution, during the period of study.

Treatment of breast cancer by radical surgery: a personal experience of 653 patients with minimal follow-up of 10 years

From June 1952 through December 1976, 695 radical operations were performed on 653 women suffering from invasive cancer of the breast. All operations were performed by a single surgeon (E.C.); the same principles in the selection of the patient techniques of surgery and overall treatment were practiced. Postoperative radiation therapy was used only in the beginning of the study, and 56 (15.9%) of the group with axillary metastases received such therapy. No patient with negative axillary lymph node received radiation therapy. No postoperative adjuvant chemotherapy or immunotherapy was administered. Complete follow-up data were obtained in 94.7% of all patients. In accord with the UICC clinical classification, 96 were classified as stage I (14.7%), 445 as stage II (68.1%), and 111 as stage III (17.%); 1 (0.1%) was not classified. From the 653 patients, 651 (two postoperative deaths) were observed for an average of 141.9 months. The longest period of follow-up evaluation for any patient was more than 35 years and the minimum, 10 years. Survival was calculated for the entire study group and for patients classified by nodal status and stage of disease. The 10-year overall survival rate for 651 patients is 60.4%; for those with positive nodes 46.4%, and for those with negative nodes, 76.7%. The overall survival, according to clinical stage, was as follows: the 5-year survival for patients in stage I was 89.5%, and the 10-year survival was 83.1%. In the stage II group, the 5-year survival was 76.1% and the 10-year survival, 58.5%. The patients in stage III had only a 62.1% 5-year survival and a 47.7% 10-year survival.

A prospective double-blind trial of a low molecular weight heparin once daily compared with conventional low-dose heparin three times daily to prevent pulmonary embolism and venous thrombosis in patients with hip fracture

In a randomized, prospective, double-blind trial, the effect of conventional low-dose heparin (5,000 units every 8 hours) was compared with that of a low molecular weight fragment (2165 LMWH, Kabi Vitrum AB, starting 2,500 units 2 hr before surgery, and then 5,000 units subcutaneously every morning for 9 days). A total of 90 patients admitted because of hip fracture fulfilled the inclusion criteria and were analyzed for development of pulmonary embolism and deep vein thrombosis: 46 patients were included in the low molecular weight heparin (LMWH) group, and 44 in the conventional heparin group. Two and three, respectively, died before diagnostic tests were performed. In the remaining patients a ventilation-perfusion lung scan was performed 8 days after intervention. In the first 57 patients studied a bilateral ascending venography was performed on the ninth day only if clinical symptoms suggested a deep venous thrombosis. Because of the rate of venous thrombosis detected in those patients was unexpectedly low, venography was requested in the remaining 33 patients, even if the screening tests were negative. Pulmonary embolism occurred in six patients, all in the LMWH group. Deep vein thrombosis occurred in 14 patients in the LMWH group and in six patients in the conventional heparin group. Both differences are statistically significant. Mortality did not differ between the groups, nor did haemorrhagic complications. Our findings suggest that, in patients with hip fracture, LMWH is not useful at the dosage used.

Epidemiology of visceral leishmaniasis in Colombia

Epidemiologic studies were conducted during the period 1986-1988 in a small rural community in Colombia (El Callejon) where visceral leishmaniasis is highly endemic. In this community of 185 people, 14 cases of infantile visceral leishmaniasis were diagnosed in the 9 years 1981-1988. Leishmanin skin testing of a sample of the human residents showed that prevalence of Leishmania chagasi infection increased with age; overall, 51.2% of the subjects had a positive reaction. A canine surveillance program was instituted, using introduced sentinel dogs as well as the indigenous dog population. Eleven of 16 sentinel dogs were infected within 8 months of exposure; mean seroconversion time was 4.4 months. Eleven of 25 seronegative local dogs were also infected during the 26 month period; mean seroconversion time was 8 months. Parasites identified by isozyme electrophoresis as L. chagasi were recovered from 18 of 22 seropositive dogs. Collections of wild animals using baited live traps yielded mainly the neotropical opossum, Didelphis marsupialis. Leishmania chagasi was recovered from 12 of 37 (32.4%) opossums. Six of 681 female Lutzomyia longipalpis collected in the community had flagellates in their guts; cultures from 4 were identified as L. chagasi. These data confirmed that active parasite transmission occurred. The relatively high prevalence of L. chagasi infection found among D. marsupialis captured near human dwellings suggests that these animals may be an important peridomestic reservoir.

Two years of cyclophosphamide and 5-fluorouracil as adjuvant chemotherapy for stage II and III breast carcinoma

The results after 6 years of a prospective clinical trial of adjuvant chemotherapy with a regimen of two drugs--cyclophosphamide and 5-fluorouracil (CF)-- for 2 years in 97 women with stage II or III breast cancer are reported. Eligible patients were free from distant metastases. All patients began adjuvant therapy within 4 weeks of surgery; therapy consisted of radical, modified, or extended radical mastectomy. No postoperative radiotherapy was given. The results are compared with a historical control group from previous consecutive patients treated by surgery alone. Patients were stratified by age (younger than 50 or older than or equal to 50) and nodal status (one to three positive axillary nodes vs. four or more positive nodes). The estimated 6-year survival was 60% for CF patients vs. 31% for control patients (P = 0.001). The estimated 6-year disease-free survival was 53.6 and 30.3% for CF and control, respectively (P = 0.007). There was a trend toward longer disease-free survival (DFS) and survival (S) in patients treated with CF, but this was not significant in all the subgroups. Disease-free survival was statistically significant in the subgroup of women greater than or equal to 50 years old with one to three positive nodes (P = 0.038); survival in the patients less than or equal to 49 years old with four or more positive nodes (P = 0.0036); and in patients greater than or equal to 50 years old with one to three lymph nodes involvement (P = 0.038).

Effect of altitude on the lung function of high altitude residents of European ancestry

The forced vital capacity (FVC), forced expiratory volume in one second (FEV), and ratio of FEV to FVC (%FEV) of 161 male and 158 female youths of European ancestry who were born at high altitudes and who were residing in La Paz, Bolivia (average altitude of 3,600 m) were examined and compared with those for lowland Europeans and highland Aymara Amerindians. FVC and FEV were significantly larger (p less than .001) in the La Paz Europeans than in two lowland control samples of European ancestry, with the relative differences between samples varying from small (1.5-4.1%) to moderate (7.7-11.9%). It could not be determined whether the enhanced lung volumes of the La Paz European children were acquired through an accelerated development of lung volumes relative to stature during adolescence, as is the case for Amerindian highlanders. After controlling for body and chest size, FVC and FEV were significantly smaller in the La Paz Europeans than in highland Aymara (p less than .001), suggesting that the lung volumes of the Aymara are influenced by factors other than simply growth and development at high altitude. Finally, as found in Amerindians, chest size is an important determinant of intra-individual variation in lung function among highland Europeans.

Radiotherapy in the management of locally advanced breast cancer

A retrospective study of 484 patients with locally advanced cancer of the breast treated with irradiation alone revealed a partial or complete response in 64% of the patients, with a mean duration of 13 months. The 5-year survival was 21.9% for the entire group of patients; 32% for patients responding, and 5% for non-responding patients. The data suggests that the size of the tumor and the age of the patients influence the quality of response. The results indicate that radiotherapy adequately controls local disease in a significant number of patients but systemic treatment is needed for better disease control.

Postoperative whole lung irradiation with or without adriamycin in osteogenic sarcoma

Thirty-six patients with histologically proven osteogenic sarcoma of the extremities, treated between September 1975 and April 1978, are the subject of this report. The primary tumor was treated with radical surgery. Patients received 2000 cGy whole lung irradiation postoperatively in an attempt to control micrometastases to the lung. Twenty-nine of the patients were given Adriamycin (60 mg/m2 IV every 6 weeks for a total dose of 550 mg/m2) in addition to the irradiation. The median, disease-free interval was 118 days for the seven patients treated with lung irradiation only. The median overall survival for these patients is 241 days, with one patient alive with disease. All patients developed lung metastasis. For the 29 patients treated with postoperative lung irradiation and Adriamycin, the median disease-free interval was 372 days, and the median overall survival is 843 days. Nineteen of the patients recurred (65.5%). The differences are statistically significant (p less than or equal to 0.003, median disease-free survival and p less than or equal to 0.03, median survival). This study supports the role of whole lung irradiation plus Adriamycin, in the control of micrometastases in osteogenic sarcoma of the extremities and suggests that additional clinical trials are warranted.

Effect of altitude on the physical growth of upper-class children of European ancestry

The physical growth of 351 upper-socioeconomic-status children (9-20 years) of European ancestry residing in La Paz, Bolivia (altitude 3600 m) is described and compared with that of lowland children of similar background. The purpose is to evaluate the independent effect of continual exposure to atmospheric hypoxia during the period of growth and development on linear growth. The data presented here indicate that the effect of hypoxia on achieved stature ranges from minimal in males and none in females to a maximum of 3 cm in both sexes. The magnitude of this effect is relatively small compared to the potential effect of other factors which affect the growth of highland children.

The physical growth of urban children at high altitude

The physical growth of urban Aymara children residing in La Paz, Bolivia (3,600 m) is described and compared with Amerindian children residing at low and high altitudes and with low-altitude U.S. children. The sample consists of 227 males (10.6-19.7 yr) and 219 females (11.2-19.8 yr). The urban La Paz children were taller at all ages than rural high altitude Amerindian children but similar in stature to urban high altitude children from Peru. The variation in stature among the high altitude populations was considerable, amounting to average differences between the tallest and shortest samples of about 10 cm in males and 8 cm in females. In addition, stature in the two urban high altitude samples was similar to that of rural low-altitude Amerindians. This overlapping of the distributions of stature in high- and low-altitude populations could easily confound comparisons designed to determine the effects of hypoxia on physical growth. La Paz Aymara children had considerably smaller chest sizes relative to stature than high-altitude Quechua children. However, the available data indicates that relative chest sizes are similar in Aymara and Quechua adults, suggesting that the process by which large chests are achieved may differ between these Andean populations.

Local control of osteogenic sarcoma by radiation and chemotherapy

Sixteen patients with osteogenic sarcoma of limbs were treated with high dose methotrexate followed by leucovorin rescue, adriamycin and radiotherapy to the primary tumor. A post-treatment surgical biopsy was performed in 15 of the 16 patients. In 12 of 15 patients (80%), the follow-up biopsy was negative for active tumor. Complications of treatment were myelosuppression (16 cases), moist desquamation (13 cases), soft tissue necrosis (2 cases) local infection (2 cases), fibrosis (9 cases) and bone fracture (4 cases). The mean survival time in this group of patients was 712 days.

Radical mastectomy versus radical mastectomy plus internal mammary dissection. Ten year results of an international cooperative trial in breast cancer

A multicentric randomized trial evaluated the interest of internal mammary dissection on operable breast cancer patients. One thousand four hundred and fifty-three patients were included in the study and were followed for ten years. There is no difference in survival or in relapse-free survival between the two groups. There were significantly more local recurrences in the group without internal mammary dissection, but these recurrences occurred mainly on patients who developed metastases. A great difference between centers was observed in the number of nodes examined and there is therefore a difference in the prognostic value of the number of nodes invaded.

Delayed regional lymph node dissection in stage I melanoma of the skin of the lower extremities

Results of a prospective randomized clinical trial conducted by the WHO Collaborating Centers for the Evaluation of Methods of Diagnosis and Treatment of Melanoma are reported. Five-hundred-fifty-three Stage I patients whose limbs were affected entered the study; 267 were submitted to wide excision and immediate node dissection and 286 had wide excision and node dissection at the time clinically positive nodes were detected. Survival curves of the two treatment groups could be superimposed. No subsets of patients benefitted from immediate node dissection. The authors conclude that delayed node dissection is as effective as the immediate dissection in Stage I melanoma of the extremities if the patient can be checked every three months. If the quarterly follow-up is not guaranteed, immediate node dissection is advisable, at least for melanomas thicker than 2 mm.