Molecular close-packing method and its application to crystal structure determination of deshexapeptide (B25-B30) insulin.

Based on the molecule-packing theory, we defined a molecule-packing function expressing the compatibility of packing among the symmetry-related molecules in a unit cell. A computer program imitating the close-packing of molecules in the objective crystal lattice and giving the function value of each rotation and translation of the molecule in the unit cell was performed, and it therefore made the close-packing of molecules express quantitatively. This method not only could judge a correct solution from several peaks of the rotation or translation function but it may also independently, quantitatively and quickly solve some specific problems of rotation and translation. Using known structure of despentapeptide (B26-B30) insulin as an example, the effectiveness of this method and its program was inspected, and this method was successfully applied to solving the translation problem of the unknown structure of deshexapeptide (B25-B30) insulin. The molecular close-packing method proved by the results of R-search and electron density maps is relatively independent of the molecular replacement method, though an effective complement of it.


A cDNA clone with anti-oncogene activity.

A cDNA clone, p14-6, which has an anti-oncogene activity on the v-Ki-Ras oncogene-transformed malignant cell line DT, was found. This clone was recovered from the revertant R14 cells, which had been isolated by transfections of DT cells with a normal human fibroblast cDNA library cloned in pcD2, an Okayama-Berg vector. When transfected into DT cells, p14-6 clone gave rise to phenotypical flat reversion in 5-15% of DT transfectant colonies. The p14-6-transfected flat cell line, RR, was proven to be a true revertant with significantly reduced malignancy by in vitro and in vivo malignancy tests. All other clones recovered from R14 cells were unable to cause this reversion. Molecular hybridizations showed that the p14-6 was inserted into RR genome as tandem repeats, and no structural change was found in the v-Ki-Ras oncogene in RR genome. These facts suggest that the anti-oncogene activity of the p14-6 clone on the DT cells may be exerted through expression of the cDNA contained in this clone.


[Systematic modelling in nutrition].

Live organisms can be considered as open complex systems in a steady state through which passes a flow of matter which undergoes a series of transformations which constitutes the nutritional process. The systemic approach and modelling procedure can be applied to nutrition as it can to other scientific areas, although examples of this particular application are few. This review describes the complexity of components in nutritional systems and presents a means of simplifying this. A section is given over to a comparative study of the main types of models (empirical vs mechanistic, static vs dynamic) which can be applied to nutrition. The other topics covered concern the modelling of the regulating systems in nutrition (homeostasis, homeorhesis), model validation and comments on application models and research.


The influence of processing corn grain on glucose metabolism in ewes.

Glucose metabolism was studied in ewes fed 800 g chopped alfalfa hay (H) or 400 g alfalfa hay and 400 g corn grain given in whole (HWC), ground (HGC) or extruded (HEC) form. Daily intake of metabolisable energy and crude protein were: 5.8 MJ, 109 g; 9.0 MJ, 84 g; 9.5 MJ, 84 g and 8.5 MJ, 88 g in H, HWC, HGC and HEC, respectively. In situ ruminal degradability ranked whole, ground, and extruded corn in ascending order. Ruminal pH and concentration of acetic acid were lower and of propionic acid higher (P less than 0.05) in HEC than in HGC and HWC groups. Plasma level of glucose (P less than 0.10), insulin (P less than 0.05), and the ratio of insulin to non-esterified fatty acids (NEFA) (P less than 0.01) were higher in HEC than in other groups. Glucose irreversible loss (GILR) and entry rate (GER), recycling (GRec) and reentry (GRee) were determined by double isotope dilution procedure. GER, but not GILR, was higher in HWC than in H and HGC (6.98 mg/min/kg BW0.75 vs 3.97 and 4.24 mg/min/kg BW0.75, respectively; P less than 0.05) and than in HEC (4.84 mg/min/kg BW0.75; P less than 0.10). GRec and GRee were higher in HWC than in the other treatments. Grinding or extruding the grain increased ruminal degradability and decreased glucose entry rate.


Pressure profile along the oesophagus during eructation in sheep.

The pressure profile along the oesophagus was recorded simultaneously with the flow rate of eructated gas in sheep to evaluate the oesophageal motor events leading to the relief of gas. All the eructation sequences started by a rise followed by a plateau of oesophageal pressure. The passage of gas at the tracheal level occurred during this plateau and not during the consecutive transient lowering of the oesophageal pressure. All eructation sequences ended by a peristaltic contraction of the oesophagus. The flow rate pattern of gas during eructation was affected by head position leading to different tensions of the oesophagus. We conclude that, despite the large volume of eructated gases, the eructation process is not significantly different in sheep compared to other animals. Therefore, by virtue of its unique physiological particularity, the sheep might be used as an experimental model for the evaluation of lower oesophageal sphincter (LOS) competence.


Microstructure of skeletal muscles of growing calves fed silage-based vs hay-based diets. II. Fibre type distribution.

As described in part I, samples of musculus longissimus dorsi, semimembranosus and semitendinosus were obtained post-slaughter from 2-week, 3-month and 10-month-old bull calves. The 2-week-old calves were fed milk only. All the remaining animals were fed grass silage or hay ad lib and a restricted amount of concentrate from 2 weeks of age onwards. Muscle fibres were differentiated according to Ziegan (1979) into fast-twitch glycolytic, fast-twitch oxidoglycolytic and slow-twitch oxidative fibres (FTG, FTO and STO, respectively). The percent distribution of individual types of fibres was estimated as related to the calves age and diet. The most numerous were always fast-twitch glycolytic fibres, the lowest values being observed in the 2-week-old calves. The effect of the diet on fibre percentage distribution in 3-month-old calves differed from that found in 10-month-old animals. This research suggests that a hay-free diet based on grass silage alters the microstructure of skeletal muscles, which thus might also affect the quality of meat.


[Effect of bean (Vicia faba) extrusion on nitrogen and starch intestinal flux in lactating cows].

Four mature lactating Holstein cows fitted with permanent ruminal, duodenal and ileal cannulae were used to study the effect of extrusion at 195 degrees C of beans (Vicia faba cv Castel) on organic matter (OM), nitrogen (N) and starch degradation in the rumen and their flow to and absorption from the small intestine. The test protein sources, raw beans (RB) and extruded beans (EB), provided about 45% of the dietary protein. The diets were composed of 23.1% beans, 56.2% corn silage, 10.1% corn grain and 10.7% Italian rye-grass hay on a DM basis; the diets were isocaloric (4.5 Mcal/kg of DM) and isonitrogenous (14% of DM). Cr-EDTA, YbCl3 and purines were used as liquid, particulate and bacterial markers respectively. Extruding the beans did not influence intraruminal pH (6.6), ammonia-N (99 mg/l) and volatile fatty acids (97 mM/l) concentrations. Apparent digestibility in total tract of energy, OM, N and starch were not affected with inclusion of EB instead of RB, the corresponding mean values were: 66, 68, 64 and 95% of intake. Apparent ruminal digestion of OM, starch and N in the forestomach were 39, 58 and 52% for diets containing RB and 38, 72 and 45% for EB diets; efficiency of bacterial protein synthesis (gN/kg organic matter truly digested in the stomach) was higher for EN diets compared with RN diets (25 vs 22). Eating diets including EB increased non-ammonia-N, bacterial-N and dietary-N flows (g/d) to the duodenum compared with diets containing RB: 409 vs 366, 216 vs 194 and 193 vs 172 respectively; while starch flow was reduced (1.5 vs 2.2 kg/d) and OM flow was unchanged (9.8 kg/d). Apparent digestion from the small intestine (g/d) of nonammonia-N, bacterial-N and dietary-N were higher for EB diets: 268 vs 229, 181 vs 160 and 87 vs 69 respectively; meanwhile, starch digestion decreased (975 vs 1,612). The PDIA, PDIN and PDIE contents (g/kg of DM) of the RB were 33, 175 and 127 respectively; the corresponding values after extrusion were: 58, 147 and 178.


Purification of an ovine, androgen-dependent epididymal protein. Evidence for a strong amino acid sequence homology with serum albumin.

An ovine, testosterone-dependent protein was purified from an extract of epididymides of orchidectomized-, testosterone-implanted rams by ethylene glycol precipitation, anion exchange chromatography, preparative non-denaturing PAGE at alkaline pH and gel filtration. The protein which had previously been named ovine prealbumin-epididymis-specific protein (oPES), migrated as a single band ahead of ovine serum albumin (oSA). A single component, with an apparent MW of 60 kDa, lower than that of oSA, was also observed in SDS-PAGE. oPES was cleaved after lysyl residues using endoproteinase Lys-C and the hydrolysate was fractionated in 2 steps by reverse-phase HPLC. Six oligopeptides were recovered and sequenced. They all displayed complete identity with regions of bovine serum albumin scattered in the two-third N-terminal part. However, in 2 of them, there was no complete identity with homologous parts of oSA. This indicates that oPES and oSA are probably encoded by different genes.


Ontogeny of the liver nuclear T3-receptor during the last days of incubation and posthatch in the chick embryo.

The characteristics of the nuclear T3 receptor in the liver of the chick embryo were studied from incubation day 18 until day 1 posthatching. Treatment of the nuclei with 3 mol.l-1 MgCl2, which removed the endogenously bound hormone, was used in order to determine the total amount of receptors. The affinity constant Ka decreased between incubation day 18 (0.996 +/- 0.276.10(9) M-1) and day 19 (0.247 +/- 0.072.10(9) M-1), remained the same thereafter until hatching and increased again on day 1 posthatching (1.846 +/- 0.928.10(9) M-1). The total amount of receptors tended to increase from incubation day 18 to day 20 non-pipping (np) (from 4.40 to 11.55 fmol/micrograms DNA) and decreased thereafter to 2.38 fmol/micrograms DNA on day 1 posthatching. The amount of free binding sites reached a maximum on day 19 (6.91 fmol/micrograms DNA) and then decreased drastically until posthatching (0.19 fmol/micrograms DNA). The maximal specific binding was found on day 20 (np), just prior to penetration of the air chamber. During the time at which the level of T3 remains high in the plasma, a reduction in the amount of receptor was observed, which may be the consequence of a down-regulation by T3 itself.


Oestrus and LH responses to oestradiol during lactational anoestrus in Chinese Meishan and large white sows.

To investigate endocrine mechanisms associated with the occasional occurrence of fertile oestrus during lactation in the high prolific Chinese Meishan (MS) breed, the incidence of oestrus and changes in plasma luteinizing hormone (LH) levels before and after oestradiol benzoate (OB, 15 micrograms/kg body weight) administration on day 22 was compared in 4 MS and 6 Large White (LW) sows. All sows exhibited oestrus in response to OB. Only 1 sow (MS) ovulated in response to OB, became pregnant and farrowed. Mean plasma LH levels before OB were low (MS: 0.38 +/- 0.06 ng LH/ml, LW: 0.29 +/- 0.04 ng LH/ml, ns). LH levels above 2 ng/ml (surge) occurred in 2/4 MS and 2/6 LW sows at 60 +/- 5 h after OB. The MS sow that ovulated had an LH surge level of 4.5 ng/ml plasma at 40 h after OB. These results indicate minor breed differences in the control of LH secretion during lactational anoestrus.


Salivary stimulation by chewing gum and its role in the remineralization of caries-like lesions in human enamel in situ.

Salivary stimulation elicited reflexively by taste and mastication leads to an increase in the pH, buffering power, and supersaturation of saliva, which can affect beneficially the balance between enamel de- and remineralization in early caries. In a previous study in which a sorbitol chewing gum was used as a salivary stimulant for 20 minutes, five times daily after meals and snacks over a three-week period (during which fluoride toothpaste was used daily), significant remineralization of caries-like lesions in human enamel attached to intraoral appliances in human subjects was observed. In view of the continued public preference for sucrose-sweetened chewing gums, the study was repeated using a sucrose gum. The mean results showed a trend toward remineralization with the use of sucrose chewing gum, which was significant in 10 subjects who chewed for 30 minutes but not in 9 who chewed for 20 minutes. The use of chewing gum after meals and snacks (in the presence of fluoride from toothpaste) can thus enhance the remineralizing potential of the mouth, probably as a result of salivary stimulation.


Effect of gum chewing on the pH of dental plaque.

Saliva stimulation by gum chewing has been reported to neutralize plaque acidity. We compared the plaque pH response to bread with honey followed by sucrose-or sorbitol-sweetened gum chewing for 20 minutes. Bread and honey was chosen as previous work in our laboratory found this a worst case challenge in terms of the extent and duration of the pH decline. The study design was factorial with: 4 subjects x 2 replicates x 3 treatments. Each subject received each of the 3 treatments: food (bread and honey), food followed by sorbitol chewing gum, and food followed by sucrose chewing gum. Subjects accumulated plaque for 3 days on a partial prosthesis with a glass electrode set in the approximal space in the gap left by a missing first molar. Plaque pH was monitored for 150 min: baseline (0-10), food (11-30), +/- gum chewing (31-50), post-chew monitoring (51-150). ANOVA of mean plaque pH showed no difference between treatments at baseline. Significantly higher pH levels (p < 0.01) were shown with both gums compared to no gum during the chew and post-chew phases. Plaque pH data were also converted to absolute acid values (cH). Food alone produced 1703 mumol/min.; food followed by sorbitol chewing gum produced 53 mumol/min.; and food followed by sucrose gum produced 156 mumol/min. While the post-chew pH curves were not identical for sucrose vs. sorbitol chewing gums, both neutralized plaque acidity, probably due to the induced salivary action.


A modified plaque pH telemetry method.

Previous plaque-pH telemetry studies reported the acidogenicity of various foods and dietary patterns to estimate potential cariogenicity. To avoid patient discomfort, improve compliance, and minimize electrode malfunctions, we have simplified our telemetry method and compared it to our previously published model. A removable partial prosthesis with a glass electrode set in the approximal space left by a missing first molar was used in 2 subjects. In the modified method, subjects suspended oral hygiene for 3 days, the prosthesis was then installed on the 3rd day, and accumulated plaque was spread on the electrode and covered with gauze for retention. In comparative tests, the same subjects wore the prosthesis in the mouth during plaque accumulation. Test sessions compared the plaque pH response to 4 treatments: a 10% sucrose rinse, a 10% sorbitol rinse, a snack roll with marmalade and coffee, and the snack followed by gum chewing. Overall, pH curves were similar (mean baselines and minimas) and no significant differences in mean pH response were noted between the 2 methods. The modified method improved subject participation, demonstrated greater reliability, and showed Stephan curves comparable to conventional methods.


Two-year longitudinal study of a peroxide-fluoride rinse on decalcification in adolescent orthodontic patients.

The purpose of the present study was to determine if once daily use of a 1.5% H2O2 rinse with 0.05% NaF was more effective in preventing decalcification in adolescent orthodontic patients than comparable use of a 0.05% NaF rinse without H2O2, or in patients using no rinse at all. Ninety-five subjects were selected consecutively from adolescents scheduled to receive fixed orthodontic treatment on both dental arches. Three groups were formed that were matched in percentages for age and sex. The first group (control group, n = 35) used a 1100 ppm F toothpaste only. The second group (NaF rinse group, n = 30) used both the same toothpaste and a once daily 0.05% NaF rinse. The third group (H2O2-NaF rinse group, n = 30) used the toothpaste and a once daily rinse containing both 0.05% NaF and 1.5% H2O2. Decalcification was assessed single-blind on the facial surfaces of all erupted teeth at baseline (before appliances were placed), and 3 months after fixed appliances were removed. The difference between baseline and post-treatment decalcification levels determined the incidence of decalcification during orthodontic treatment. Since the first molars were found to have the highest decalcification scores, separate analyses of variance were carried out for the whole mouth and first molar assessments. A p value of less than 0.05 was considered statistically significant. The results showed no significant differences between any of the groups before orthodontic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)


Non-Hodgkin's lymphomas in children. I. Patterns of disease and classification.

Non-Hodgkin's lymphomas (NHL) are part of an overlapping spectrum of lympho-proliferative diseases in childhood. In the first of this 2 part series, the clinicopathological aspects of NHL in childhood are discussed. The rapid progression of disease, the high incidence of micrometastases (over 80%) at diagnosis, and the propensity of hematogenous spread to the bone marrow and the central nervous system (CNS) as well as the clinico-pathologic 'clusters' associated with particular presenting sites distinguish the pediatric forms of disease. Abdominal primary sites most frequently manifest diffuse undifferentiated (Burkitt's or non-Burkitt's) histopathology, B-cell immunophenotype, FAB-L3 cytomorphology and specific karyotypic and/or genotypic alterations of the immuno-globulin genes and the c-myc oncogene. Mediastinal presentation is associated with lymphoblastic histopathology, T-cell immunophenotype and a variety of less consistent karyotypic and genotypic aberrations. Ki-1 lymphoma, a rare subtype of large cell NHL with specific features is often of T cell origin. The requirements for diagnosis, staging and monitoring are presented in the context of the associations between clinico-pathological presentation and subsequent behavior. The most frequent sites of disease progression and relapse are involvement of the bone marrow and the CNS. For Burkitt's lymphoma there is a historic perspective and a description of particular epidemiologic, clinical, virologic, immunophenotypic and genotypic features. Cytogenetic and molecular biologic studies of genomic rearrangements are advancing the understanding of oncogenesis, clonality, lineage, and clinical behavior. The capacity to detect and amplify DNA from submicroscopic disease may contribute to prognostic stratification both at diagnosis and during subsequent monitoring.


Non-Hodgkin's lymphomas in children. II. Treatment.

The prognosis of non-Hodgkin's lymphoma (NHL) in childhood has improved steadily in the last 2 decades. This is primarily the result of increasingly effective chemotherapy regimens tailored to defined and relatively homogeneous prognostic categories and tested in prospective clinical trials. Surgical excision remains of prognostic benefit only when near-total resection can be performed without delay of chemotherapy. The role of radiation therapy is now limited to the treatment of overt central nervous system (CNS) lymphoma, disease unresponsive to chemotherapy, and certain emergencies. Effective 'prophylactic' treatment of the CNS has been achieved in most series by intrathecal and systemic chemotherapy alone. The most relevant modality of treatment is chemotherapy and a very large number of protocols have been published. The origins of current multi-agent regimens stem both from early experience with cyclophosphamide in endemic Burkitt's lymphoma and from therapeutic studies of acute lymphoblastic leukaemia. Sub-stratification of non-localized NHL has produced protocols designed for either lymphoblastic (mostly T cell) or non-lymphoblastic (mostly B cell) categories. While the cure rate for lymphoblastic lymphoma now exceed 70%, the non-localized non-lymphoblastic disease remains a major obstacle to cure. These patients frequently present with large abdominal primaries and are prone to regional as well as hematogenous dissemination. In particular, involvement of the CNS is now considered to be the most adverse prognostic variable in this group. Recently, highly intensive regimens are addressing these obstacles. On the other hand, NHL defined as localized has been shown to be curable in up to 95% of children with the use of simple chemotherapy regimens as short as 6 months in duration. Salvage of patients who relapse during or after chemotherapy remains bleak but cures are possible with regimens incorporating bone marrow transplantation from either an autologous or allogeneic source. Experimental methods, including biologic and immune response modifiers may also offer future promise.


[Omega-6 and omega-3 polyunsaturated fatty acids in healthy and sick children under 5 years of age. Part II. Pathologic metabolism].

Today, the long-chain polyunsaturated fatty acids, omega 6 and omega 3, are of special interest to different research groups, all over the world, due to its physiological and metabolic importance. This paper presents different cases of fatty acids deficiency from which the cases of premature low-birth-weight neonates and children under 5 years old presenting severe malnutrition, stand out. In addition, various inherited pathological processes that involve the mechanism of oxidation of these nutrients, are also described.


[Differential physical growth during the first year of life. I. Body growth].

Keeping up to date the children growth and development standards, it is a necessity of main order for Health Secretary, because of it is possible an adequate pediatric evaluation. The present study, reports the results of a longitudinal research on growth in children of both sexes and ages from 0 to 1 year of extrauterine life. In all, we got 44 growth measures of the body, head and corporal composition. This report describes the shape of growth body, illustrates the general parameters of growth: stature and weight. Also it includes the dates correspondent to corporal segment growth: sitting height, upper and lower segments; upper extremity, upper arm, lower arm, hand, lower extremity, thigh, leg and foot lengths; ankle height; biacromial, bicrestal, thorax, elbow, wrist, hand, knee, ankle and foot breadths; and thorax depth. Moreover, we report the final increments for corporal segments studied, and the differences on sexual dimorphism. We describe the methodology, socioeconomic and cultural custom results. The sample was classificated within middle lower social class.


[Circumcision in the newborn child and risk of urinary tract infection during the first year of life. A meta-analysis].

To assess if neonatal circumcision may decrease the incidence of urinary tract infection (UTI), published papers on these topics were reviewed, to address their methodological shortcomings, and to analyze them in individual and grouped form. A systematic search of the papers on circumcision and UTI was conducted in Index Medicus (1975-1991) and MEDLINE (1988-1991). Six papers were included in the meta-analysis because all of them presented original data obtained from groups of patients. All of the elected articles were considered in individual and grouped form to calculate odds ratio (OR) and confidence interval at 95% (CI 95%). The number of patients included in each paper ranged from 112 to 219,775. Clustering of the articles enabled us to obtain a global sample number of 221,799 patients. In each individual article there was a higher risk of UTI in uncircumcised patients (OR from 10.82 to 156.42). Global risk obtained from the six clustered papers was of 13.05 with a CI 95% from 10.86 to 15.70. Uncircumcised males have low risk of UTI during their first year of life, but the risk may decrease even more with circumcision. This conclusion may not be considered as definitive because of the methodological shortcomings of the papers reviewed. Recommendation of routinely circumcision to all newborns in not justified with these data.


[Treatment of children with acute diarrheal disease. Knowledge and attitudes of the health personnel].

Diarrheal diseases are still one of the most frequent causes of death due to dehydration in children; lack of information regarding the adequate treatment of diarrhea is the main cause. The results of an inquire sent to 620 physicians and nurses were analyzed to determine the knowledge and attitudes of the health care workers that reside in different diarrheal mortality areas in Mexico. The less professional experience time was correlated with more knowledge in etiology of diarrhea. More physicians than nurses had correct answers regarding the place of diarrheal diseases in child mortality and the correct use of antimicrobial, and other drugs and liquids to prevent and treat dehydration. Most workers did not know the inconvenience of hypertonic solutions to prevent dehydration and the importance of the oral solution flavor. This results suggest that nurses will, be included in clinical training by means of seminars in oral hydration therapy. Furthermore it seems convenient to increase the access to oral hydration solutions as well as the diffusion of its advantages.


[Nosocomial infection in the neonatal period at a third level care center].

Results are presented on epidemiologic surveillance of nosocomial infection of all neonates attended at the Instituto Nacional de Perinatologia throughout 1988-1990, reporting rates of 2.1, 2.9 and 5.5 per 100 discharge for each of the years studied. Data are presented in full by service, showing rates of 4.7, 9.5 and 23.0 per 100 discharge in Neonatal Intensive Care Unit (NICU) and 1.5, 3.2 and 6.7 per 100 discharge for Neonatal Intermediate Care (NIC) for the same three years. With respect to type of infection, septicemia, pneumonia and conjunctivitis come as the most frequent causes of infection and Staphylococcus sp coagulase negative (30%), Staphylococcus aureus (27%) and Escherichia coli (7%) as the prevailing microorganisms in nosocomial infection.


[Morbidity reduction in preterm newborns fed with milk of their own mothers].

In order to study the effect of feeding on the morbidity, 118 premature newborn, were followed on successive basis; 59 fed with infant term formula (F) and 59 fed with own mother's milk (LH). The patients were classified in 3 groups according to birth weight: I, < 999 g (n = 4/4); II, 1000-1499 g (n = 37/37) and III, 1500-1999 g (n = 18/18), each group F and LH having equal numbers. Growth, morbidity and clinical management were recorded. Necrotizing enterocolitis (P < 0.001), urinary tract infection (P < 0.01) and infectious diarrhea (P < 0.01) were less frequent in LH infants and as a consequence these infants needed less antimicrobial therapy (P < 0.001), nevertheless the human milk contained flora bacteria. The LH infants of group II need fewer red cell transfusions (P < 0.001) and each group was similar and only the babies < 999 g had increments of approximately 15 g/kg/day. This study highlights the importance of feeding the premature infant with own mother's milk; however, the infant growth increments were less than the expected suggesting that human milk must be fortified with proteins and minerals, considering the mothers as a true human milk bank.


[Spondyloepiphyseal dysplasia tarda with progressive arthropathy: 2 siblings affected].

We described a Mexican family whose parents were consanguineous. Therefore two children were affected by a progressive arthropathy with deformity in all finger joints, restricted joint mobility and broad major joints. This condition was diagnosed like atypical juvenile rheumatoid arthritis (JRA) because the test for serum rheumatoid factors and antibodies were negative and failed to respond to anti-rheumatoid treatment. However their radiographic studies showed the spine with universal platyspondyly, enlargement epiphyses of the hands, the absence of destructive and the presence of the dysplastic bone changes. These manifestations permit us to do the diagnosis of spondyloepiphyseal dysplasia tarda with progressive arthropathy. In this report we suggest that a complete radiologic study of the patient will allowed to diagnosis this hereditary autosomal recessive entity; likewise it will let us differ of JRA and others polyarticular conditions of childhood.


[The Mortality Committee: a hospital need].

Mortality Committees are multidisciplinary teams whose function is to analyze preventable causes of death in order to decrease the death rate, to contribute to the education of medical and paramedical staff and also to advise the hospital authorities in medical and administrative decision-making. In this paper we discuss the activities of the Mortality Committee of the Hospital de Pediatria from May 1989 to May 1991. The review comprised 202 death cases occurred during this period, and was carried out by the medical personnel involved in attending those cases while alive. In 42.5% of these cases the review was supplemented by the necropsy results. Patients' personal data, referral source, status on admission, principal disease, direct cause of death, adequacy of laboratory test and other studies, clinical/pathological correlation and suggestions to improve medical care are discussed. We suggest for every hospital the convenience of having this committee in order to improve the quality of medical care.


[Omega-6 and omega-3 polyunsaturated fatty acids in healthy and sick children under 5. I. Normal metabolism].

The polyunsaturated fatty acids, omega 6 and omega 3, are organic compounds that have to do with the daily caloric intake; the tissue deposits of energy reserve, as well as the general intermediary metabolism of the human organisms and the composition of all the cellular membranes. This article is about its general characteristics: chemical structure, essenciality, biosynthesis, and physiological and metabolical functions; its compounds and metabolites derived; its organic distribution, and the quantity found in food in general. Of all these, special emphasis are made on the essenciality of linoleic and alpha-linolenic acids, due to its metabolic importance.


[Permanent pacemakers in children. The indications, complications and long-term follow-up].

Definitive pacemakers were placed in 27 children from June 1970 to October 1988. The indication for the pacemakers was congenital auriculoventricular block in 12 patients who were symptomatic; 8 were children with postoperative auriculoventricular block; 4 had developed complete auriculoventricular block from myocardiopathies and 3 from idiopathic sick-sinus syndrome. Two patients died: one 4 months after placement of the pacemaker due to unrelated causes, and the other 14 years later due to fracture of the electrode. There were 23 who were reoperated for different reasons but the most frequent was battery failure in 8 patients and pacemaker malfunction in 4 patients. The electrode was implanted in the epicardium in 21 patients and via subclavian vein into the endocardium in 6 cases. The growth and development physically and mentally were normal during the follow-up of these children. The average follow-up period was 55.6 months.


[The perinatal aspects of surviving low-birth weight neonates].

We analyzed prenatal history of 277 live low birth weight infants (less than 2,500 g). We tried to determine some perinatal factors that may be associated with good prognosis in this group of babies. The variables analyzed were: maternal age, number of prenatal visits, complication of pregnancy, mode of delivery, birth weight, sex, gestational age. Apgar score at 1 minute and the neonatal morbidity. The population was divided in 3 groups: 1. Less than 1,000 g, (3).2. 1,000-1,499 g, (37) and 3. 1,500-2,499 g (237). Each group was also divided in appropriate for gestational age (AGA) and small for gestational age (SGA). We found that morbidity and the risk of death, is less in the SGA compared with AGA, associated with better prenatal care, higher birth weight and gestational age.


[Morbidity-mortality due to exchange transfusion in a general hospital. A prospective study].

In this prospective study, the complications and mortality appeared in 50 exchange transfusions (ET) were analyzed. The ET were performed in 84% of the cases through a catheter in the umbilical vessels, 22 through both vessels, 10 by vein and 10 by umbilical artery; in the rest of cases by central vein. We found complications in 33% of the cases. Cardiac arrhythmia (23 cases) was the most frequent complication; also metabolic complications in 20 cases, septic complications in 10 cases (8 cases of omphalitis and 4 of sepsis were included), 8 cases of necrotizing enterocolitis and 3 of bleeding were found. Some of the newborns has 2 or more complications at the same time. The total lethality rate was 4% which occurred in 2 preterm infants with critical state. Our finding suggest that morbidity due to ET is highest than previously reports and maybe the mortality is due to the critical state of patients more than the ET.


[The degree of agreement of the clinical and the histopathological diagnoses in a tertiary medical care pediatric hospital].

In Pediatric Hospital, from the National Medical Center, of the Mexican Institute of Social Security were analyzed 96 histological pieces: 59 biopsies, 21 surgical material and 16 slides. There were showed the agreement rate between clinical diagnosis and the end histopathological report from the Pathology Department. The higher correlation rate were with biopsies (83%) and surgical material (81%) and the lowest rate were with slides samples (69%). There were not statistical difference in the 3 study groups (P greater than 0.05). The overall concordance with the clinical diagnosis were 82%. The overall concordance with the 3 study groups were 80%. It is concluded what agreement rate was satisfactory in biopsies and surgical material and the agreement rate measure is an actual parameter in evaluation of clinical competence and also in the evaluation of medical care quality.


[Congenital cystic adenomatoid malformation of the lung. A report of 12 cases].

The congenital cystic adenomatoid malformation of the lung is uncommon. In the Hospital Infantil de México Federico Gómez, 12 cases have been seen over a period of 31 years, which points out how rare this malformation is. There was a male predominance, and 75% of the patients had symptoms by 8 months of age. The main complaints were progressive respiratory failure in the newborn period and recurrent lung infection in older children. Treatment was surgical in all cases. There was only one fatality due to cardiac failure.


[Splenic abscesses. A case report and review of the literature].

This is a report of a case of a 3-year-old boy who developed splenic abscesses after a mild plantar wound. His initial complains were fever and several distal cutaneous abscesses (septic emboli). Multiple cultures for bacteria, fungi, mycobacterium and anaerobes were performed, but all were negative. In spite of an energetic antimicrobial treatment, he continued with high fever. Echocardiography was normal. Two weeks later, a thoracic radiography showed the left hemidiafragm was elevated and a small pleural effusion. An abdominal echosonography showed multiple hypoechoic splenic lesions, and this finding was confirmed by magnetic resonance imaging. After splenectomy, the patient healed and was discharged. Anatomopathological examination of the spleen showed eight pyogenic abscesses of different size. The causal agent was not isolated.


[Rapid intravenous rehydration in acute diarrhea].

With the use of oral rehydration, the need for the use of endovenous rehydration has decreased considerably. Albeit, the use is still necessary in severely dehydrated patients or when oral rehydration fails. Textbooks produced in developed countries recommend slow administration of fluids to correct dehydration in 12 to 24 hours. In developing countries, due to the great number of severely dehydrated patients, this approach is not useful. We developed, during the last 20 years, an approach to intravenous rehydration that permits rehydration of the severely ill patient in a much shorter time (2 to 3 hours) and permits an early refeeding. It can be used in all patients, even newborns or malnourished. No laboratory tests are necessary. Only a small number of simple and readily available solutions are used to prepare the electrolyte mixtures.


Haloperidol does not alter expression of ethanol-induced conditioned place preference.

A recent experiment (Risinger et al., Psychopharmacology, 107 (1992) 453-456) has shown that haloperidol does not prevent acquisition of ethanol-induced conditioned place preference, suggesting that dopaminergic mechanisms do not mediate the primary rewarding properties of ethanol. The present experiment examined whether haloperidol would prevent the expression of conditioned reward to ethanol-paired stimuli using the place conditioning paradigm. DBA/2J mice received four pairings of a tactile stimulus with ethanol (2 g/kg, IP). A different stimulus was paired with saline. Before preference testing, different groups received one of three doses of haloperidol (0, 0.05 or 0.1 mg/kg); ethanol was not given. Haloperidol produced a dose-dependent decrease in locomotor activity, but did not affect conditioned place preference. These results suggest that expression of ethanol-induced conditioned place preference is mediated by non-dopaminergic mechanisms.


The effects of V4 lesions on the visual abilities of macaques: shape discrimination.

Monkeys with bilateral ablation of cortical visual area V4 were compared with unoperated controls for their ability to relearn postoperatively a series of preoperatively acquired two-choice visual discrimination problems. The animals with V4 lesions were impaired on relearning to discriminate between different shapes, and discrimination between identical shapes presented at different orientations was also impaired. Some of the deficits were consistent with disrupting the input to inferotemporal cortex, but discrimination of a subset of the stimuli is known to be unaffected by inferotemporal cortex lesions and could not be explained in the same way. To clarify the nature of the deficit, and to test the hypothesis that shapes differing in orientation are analyzed in the occipitoparietal processing pathway, animals with V4 lesions were also compared to normals on their ability to acquire a version of the landmark task. The V4 animals performed as well as the control animals on this task. The results suggest that V4 is important for the shape discrimination abilities that survive inferotemporal cortex lesions. The role of V4 in shape analysis is discussed in the light of recent evidence that V4 neurones are modulated by visual attention.


Modulation of visually evoked responses in units of the ventral lateral geniculate nucleus of the rat by somatic stimuli.

Single unit activity was recorded from the ventral part of the lateral geniculate nucleus (vLGN) in rats anaesthetized with urethane. Most of the cells located laterally in the nucleus were excited by light. The studied vLGN neurones did not respond to electrical stimulation of the tail, but about half of them changed their response to light significantly when the light flash was paired with the electrical stimulation. When the tail stimulus preceded the light, the changes consisted in a pronounced facilitation of flash-evoked activity. When the electrical stimulus was applied after the flash in a forward conditioning paradigm, facilitations were less pronounced and responses of some neurones were suppressed. These results are in contrast to those of similar experiments on the dorsal LGN, neurones of which were mainly facilitated by the conditioning paradigm. Thus, light-evoked activity of ventral geniculate cells can be enhanced by arousal-related processes.


Intrinsic and extrinsic influences on play fighting in rats: effects of dominance, partner's playfulness, temperament and neonatal exposure to testosterone propionate.

Play fighting is a frequent activity of juvenile rats and appears to show marked variability amongst individuals in that some rats play a great deal and others very little. This study attempted to identify some of the factors involved in producing this individual variability. The major influence over an individual's frequency of play as a juvenile was found to be the frequency of play by the partner. That is, play appears to be contagious, in that a high playing animal stimulates its partner to play frequently as well. In male juveniles, but seemingly not in female juveniles, the subsequent adult status of one partner as dominant influences the subordinate-to-be to initiate more playful contacts. In addition to these extrinsic influences, however, there appear to be intrinsic factors that influence whether an individual is a high or low playing animal. One intrinsic factor appears to be 'boldness', so that bolder animals tend to initiate more playful contacts. Higher players tend to be more susceptible to the stereotypy-inducing effects of the dopamine agonist, apomorphine, and tend to be more dependent upon the playful activity of the partner to maintain their own high levels of play. Both of these characteristics are consistent with other studies comparing bold and timid rats. Boldness, however, only seems to influence how much play a rat will exhibit, not how much play it is capable of exhibiting. Neonatal testosterone augmentation increases juvenile play fighting but not apomorphine susceptibility, suggesting that a high player need not be a bold animal. The total frequency of play an individual is capable of initiating appears to depend upon perinatal exposure to androgens. Boldness and the playfulness of the partner appear to modulate the expression of this hormonally set value.


Role of pups' ultrasonic calls in a particular maternal behavior in Wistar rat: pups' anogenital licking.

Stimuli from pups maintain maternal behavior in the postpartum period. Olfactory cues are strongly involved in a particular component of maternal behavior: anogenital licking (MAGL). In addition to the olfactive stimulus, ultrasonic calls from pups are critical in ensuring pup survival. Pups emit vocalizations in distress situations. In a first experiment, pups' calls are recorded around MAGL sequences. In 2 out of 3 cases these calls appear to induce MAGL behavior from the dam with preputialectomised pups as well as with intact pups, but preputialectomised pups alone call again at the end of MAGL sequences. In a second experiment, ultrasonic calls from pups emitted just before AGL sequences were recorded and played back to dams in a glass-dish selection test. Whatever the pups' treatment (preputialectomised or sham), dams showed the specific ingestive behavior towards filter paper impregnated with dodecyl propionate (DP) when auditory cues (pups' ultrasonic calls) and olfactory cues (DP) were combined. The coordination of pups' ultrasonic calls and anogenital odor in MAGL behavior is discussed, ultrasonic calls might be an inducing factor and DP the regulating factor.


Limbic seizures, but not kindling, reversibly impair place learning in the Morris water maze.

We investigated the effects of kindling and kindled seizures in different limbic structures on place and cue learning in the Morris water maze. The triggering of seizures by stimulation of the perforant path, septum, or amygdala prior to daily training impaired place learning, but had little effect on visible platform training or swim speed. Seizures triggered by stimulation of the medial perforant path after daily training also impaired place learning. Conversely, place learning proceeded normally in rats tested 24 h after kindling triggered by stimulation of the perforant path, septum, or amygdala, indicating that kindling per se does not affect place learning. Each group was able to learn the location of a reversed platform when pretraining seizures were discontinued; and perforant path and septal kindled rats, but not amygdaloid kindled rats, were impaired at learning the location of a reversed platform when seizures were triggered before training. The results confirm previous reports that limbic seizures produce amnesia, but they contradict the finding that hippocampal kindling impairs learning on tasks sensitive to hippocampal lesions.


Neural correlates of frog calling: production by two semi-independent generators.

The anterior preoptic nuclei of the isolated brainstem of male, Northern leopard frogs (Rana p. pipiens) were stimulated electrically and neural correlates of mating calling recorded from the rhombencephalic mating calling pattern generator. Lesions of discrete areas of the brainstem showed that the mating calling generator is separable into two generators, the pretrigeminal nucleus and the classical pulmonary respiration generator (which is approximately co-extensive with the motor nuclei IX-X). Each of these still can produce pulses when isolated from the other. Their interaction changes the expiratory phase of breathing into the vocal phase of calling. All stages of intermediates between these phases could be seen. An updated and simplified model of call production and evolution is presented.


Metabolic activity in the hyperstriatum of 2-day-old chicks during optomotor and contrasting visual stimulation.

Our earlier report of differences in metabolic activity within the visual regions of the hyperstriatum and ectostriatum, in 2-day-old chicks compared with 23-day-old chicks, suggested that two visual pathways within the visual system develop at different rates. Here we have investigated whether the demands of varying visual environments will increase the activity of the hyperstriatum accessorium (HA) in 2-day-olds. Metabolic activity in the HA was monitored in 2-day-old chicks by the radioactive 2-deoxyglucose technique during monocular stimulation with three different visual environments: moving stripes in a rotating drum, which induced eye and head movements, a featureless white environment, and the complex visual environment of the home cage with other chicks. Although a small but significant level of activity was found in HA in the hemisphere opposite the open eye, the activity did not vary with the visual treatment. On the other hand, a raised level of activity in the hyperstriatum dorsale (HD) appeared in chicks viewing the rotating stripes, indicating that at this age the thalamo-hyperstriatal pathway may be involved in processing whole-field visual movement. The optomoter environment also produced high activity in the medial hyperstriatum ventrale (MHV), a region that has been implicated in memory formation of imprinting. We suggest that during the sensitive period for imprinting, HA may either have not developed its fully functional capacity, or that following or during imprinting it is actively shut down to protect itself and associated regions from interfering visual input. In contrast to the 2-day-olds, 17-day-old chicks in a visually rich cage environment, had high levels of activity in HA, demonstrating that the functional maturation of the HA, related to performance in the cage environment, is complete at least 6 days earlier than previously observed.


Auditory working and reference memory can be tested in a single situation of stimuli for the rat.

The comparison of working and reference memory is one of the most valuable research angles for revealing the precise neural mechanisms of memory. The present study introduces a method to test both auditory working and reference memory during a short period in the rat. The apparatus and stimuli are identical for both memory tasks. High and low tones, between which lies a 5-s interval, are continuously presented. The task for working memory is a continuous nonmatching-to-sample. The rat makes go and no-go responses to indicate whether the current tone is the same as (match) or different from (nonmatch) the preceding tone. The task for reference memory is a continuous discrimination. The rat makes go responses on high-tone trials and no-go responses on low-tone trials. With alternate training in these tasks, the rat comes to perform well in both tasks. The rat can only know which task is employed in a given session from its own response-reward contingency during the early trials of each session.


Pressure on the snout immobilizes the spontaneously active, scopolaminized, and amphetaminized hyperactive rat.

Rats that are brought into a novel environment or that are given stimulants or anti-muscarinic drugs exhibit high levels of motor activity. Application of moderate pressure on the sides of the snout of such rats results in immediate cessation of all movements for extended time periods. Hippocampal electrocorticograms show that hippocampal slow wave activity during such induced immobility is equivalent to the hippocampal slow wave pattern typically associated with spontaneous immobility. However, neocortical activity following scopolamine administration contains more 2-6 Hz irregular activity during spontaneous than induced immobility.


The effects of early experience on callosal development and functional lateralization in pigmented BALB/c mice.

A proportion of animals of the BALB/c inbred mouse strain have an unusually small (sometimes absent) midsagittal area of the corpus callosum (CC). In this study, we used a large sample of both males and females (total n = 198) from a pigmented congenic BALB/c line to investigate the relations among preweaning handling, area of CC, and direction and degree of lateralization as measured by Collins' paw preference task. Twenty litters were handled daily from the day after birth until day 25 (weaning) according to Denenberg's procedure and 18 litters were left undisturbed until weaning. All animals were tested for degree and direction of paw preference in a modification of Collins' apparatus at about 60 days and measures taken on CNS structures at 100 days of age. There were no handling or sex effects on degree or direction of paw preference or on the extent of CC defects, but for animals in the normal range (CC > or = 0.7 mm2), those which had been handled had significantly smaller callosa. No significant differences were detected between right and left hemisphere weights, and these measures did not appear to be related to the behavioural measures. There was no significant correlation between CC area and degree of paw preference nor was there any relationship between total agenesis and degree of handedness. This last result is particularly interesting in light of recent evidence that ILn/J mice, all acallosal, are exclusively ambilateral.


Spatial deficits and hemispheric asymmetries in the rat following unilateral and bilateral lesions of posterior parietal or medial agranular cortex.

Studies of spatial behavior in both the human and non-human primate have generally focused on the role of the posterior parietal and prefrontal cortices and have indicated that destruction of these regions produce allocentric and egocentric deficits, respectively. The present study examined the role of the rodent analogs of these regions, the posterior parietal (PPC) and medial agranular (AGm) cortices, in egocentric and allocentric spatial processing, and whether spatial processing in rodents is organized in a hemispatial and/or lateralized manner as has been found in the primate. Eighty male rats receiving either a unilateral or bilateral lesion of AGm or PPC were examined on an egocentric (adjacent arm) or an allocentric (cheeseboard) maze task. The results indicated that PPC and AGm have dissociable spatial functions. Bilateral AGm destruction resulted in egocentric spatial deficits, and unilateral AGm operates demonstrated an intermediate deficit. In contrast, bilateral PPC operates demonstrated a severe deficit in allocentric processing. In addition, there were lateralized differences in the performance of unilateral PPC operates. While right PPC lesions resulted in a significant deficit on the allocentric task, no such deficit was seen in left PPC operates. In addition, neither unilateral AGm nor unilateral PPC operates demonstrated a hemispatial impairment on either the egocentric or allocentric tasks.


Does the type of prehension influence the kinematics of reaching?

Kinematic studies have indicated that when a subject reaches to grasp an object, the movement consists of two primary components: (a) a transport phase whereby the hand is brought towards the object and (b) a grip phase whereby the hand changes shape in anticipation of the grasp. Using a visual perturbation paradigm, we investigated the effect of different grip component strategies upon the transport phase. The distal strategy was determined by the size of the object to be grasped: for the small object (1.5 cm o.d.) subjects naturally adopted a precision grip between the index finger and thumb; for the large object (6 cm o.d.) subjects used a whole hand prehensile grip. During 20% of the reaching trials the perturbation was introduced by unexpectedly changing the object size. The results showed that corrections to the distal program in response to the perturbation were preceded by changes in the deceleration phase of the proximal component. The data supported previous findings of two visuo-motor channels for this prehensile movement but indicated that when unanticipated shifts of only the distal program are required, both channels show modifications.


Pimozide prevents the development of conditioned place preferences induced by rewarding locus coeruleus stimulation.

Electrical stimulation in the vicinity of the cell bodies of the locus coeruleus (LC) has been shown to support self-stimulation behaviors in rats. In the present study, a Conditioned Place Test, sensitive to both rewarding and aversive qualities of brain stimulation, was employed to determine (a) whether rewarding locus coeruleus stimulation would result in place preferences and (b) if so, whether dopamine receptor antagonism would affect the development of such place preferences. Animals were pretreated with pimozide (0.0, 0.5 or 1.0 mg/kg) prior to exposure to two distinctive environments only one of which was paired with locus coeruleus stimulation. Rats that received vehicle injections prior to stimulation/place pairings developed strong preferences for the stimulation-paired environment while those animals pretreated with 0.5 mg/kg pimozide showed no reliable shift in preference from baseline performance. Additionally, animals injected with the 1.0 mg/kg dose of pimozide exhibited mild place aversions to the stimulation-paired environment. It is hypothesized that dopamine neurotransmission is important for the rewarding effects of locus coeruleus stimulation without which such stimulation appears to be aversive.


Medial frontal cortex lesions impair the aiming component of rat reaching.

This study examined the contribution of medial frontal cortex (the medial portion of supplementary motor cortex, or Fr1) to the performance of rats on trained, or 'skilled', reaching tasks. Unilateral medial frontal cortex lesions moderately impaired reaching success on a task that demanded accuracy but they did not impair performance on a less demanding reaching task nor did they affect limb preference. Kinematic analyses indicated that the aiming component, in which the forearm of the limb is aligned along the midline of the body by adduction of the elbow, was chronically impaired. Rather than adducting the elbow to aim, the rats used a number of limb and whole body postural adjustments to compensate for incomplete or absent aiming. That medial frontal cortex is involved in the execution of at least one component of skilled reaching implies that a larger area of frontal cortex is involved in skilled limb movement than has been suggested by previous studies. The results also suggest that the different regions of frontal cortex may each have a relatively selective involvement in the execution of only a subset of the movements comprising a reach.


Protective effects of dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate on damages of isolated rat hepatocytes induced by carbon tetrachloride and D-galactosamine.

The protective effect of biphenyl dimethyl dicarboxylate (DDB) on chemically induced damages was studied in isolated suspended rat hepatocytes. The experimental results showed that DDB (200 micrograms/10(6) cells) efficiently protected the hepatocytes against carbon tetrachloride (CCl4 10 mmol.L-1) and D-galactosamine (1 mmol.L-1) induced damages. Membranal lipid peroxidation (malondialdehyde, MDA formation) and glutamic pyruvic transaminase (GPT) release from the hepatocytes were markedly decreased. The damage of the cell surfaces of the hepatocytes were also reduced as seen under a scanning electron microscope (SEM). Pretreatment with DDB (300 mg.kg-1) orally ameliorated the reduction of liver glycogen and blood glucose caused by ip injection of D-galactosamine (800 mg.kg-1) in mice. When normal rats were given DDB 300 mg.kg-1 once daily for 10 d, the free ribosomal protein and RNA in the liver increased significantly. These results indicate that DDB is of beneficial effects on both damaged and normal hepatocytes.


Comparison among three screening methods for aflatoxigenic isolates.

Seventy-six isolates of Aspergillus flavus, which were isolated from one hundred food stuffs in Zhejiang Province, were detected with RMC, AMCS and APA methods for aflatoxigenicity. The rates of toxigenic isolates detected by the three methods were 11.8%, 18.4% and 9.2% respectively. There were twenty toxigenic isolates detected by the three methods (26.3%) AMCS method was better than other methods. False negatives appeared in all methods. False positive appeared in both AMCS method and APA method. It was suggested that AMCS method may be a safe, simple and reliable method for screening toxigenic isolated if some aspects were improved.


Protective effect of dimethyl-4,4'-dimethoxy-5,6,5', 6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate (DDB) against carcinogen-induced rat liver nuclear DNA damage.

The protective effect of DDB against carcinogen-induced DNA damage was examined in the present investigation. Preincubation of rat liver nuclei with DDB (1 mmol.L-1) resulted in 60% inhibition of binding of 3H-benzo(a)pyrene to nuclear DNA. Unscheduled DNA synthesis (UDS) induced by aflatoxin B1 (10(-7) mol.L-1) in freshly isolated rat hepatocytes was also inhibited by DDB (10(-6)-10(-3) mol.L-1). Oral administration of DDB at 200 mg.kg-1 once daily for 3 d induced a significant increase of liver cytosol glutathione-S-transferase and microsomal UDPG-transferase activity in mice. These results indicate that DDB is able to directly or indirectly antagonize certain carcinogen-induced DNA damages.


Effect of nickel on some aspects of protein metabolism in selected organs of the freshwater mussel Lamellidens marginalis.

The levels of soluble, structural and total proteins, and the activities of A1AT and AAT decreased along with an increase in the levels of free amino acids and the activity of protease in the ctenidium, hepatopancreas and foot of the freshwater mussel L. marginalis after 1, 2, 3 and 4 d of exposure to a lethal concentration (115 mg.L-1) of nickel. But the activity of GDH and the level of urea decreased in the hepatopancreas and increased in the ctenidium and foot. A reverse trend was observed in the level of ammonia. In a sublethal concentration (23 mg.L-1), the levels of soluble, structural and total proteins and ammonia decreased in these three organs of the mussel after 1, 5, 10 and 15 d of exposures, with an increase in the levels of free aminoacids, urea and in the activities of protease, A1AT, AAT and GDH. The extent of these changes differed in degree depending on exposure period in the lethal and sublethal concentrations. The results are discussed in order to arrive at the degree of metal stress on the overall nitrogen metabolism of the mussel according to the period of exposure to lethal and sublethal concentrations of nickel.


Quantitative risk assessment for lung cancer from exposure to metal ore dust.

To quantitatively assess risk for lung cancer of metal miners, a historical cohort study was conducted. The cohort consisted of 1113 miners who were employed to underground work for at least 12 months between January 1, 1960 and December 12, 1974. According to the records of dust concentration, a cumulative dust dose of each miner in the cohort was estimated. There were 162 deaths in total and 45 deaths from lung cancer with a SMR of 2184. The SMR for lung cancer increased from 1019 for those with cumulative dust dose of less than 500 mg-year to 2469 for those with the dose of greater than 4500 mg-year. Furthermore, the risk in the highest category of combined cumulative dust dose and cigarette smoking was 46-fold greater than the lowest category of dust dose and smoking. This study showed that there was an exposure-response relationship between metal ore dust and lung cancer, and an interaction of lung cancer between smoking and metal ore dust exposure.


A study on genotoxicity of cooking fumes from rapeseed oil.

The present article reports the genotoxic potential of rapeseed oil cooking fume investigated by a battery of short-term tests (Ames test, SCE/V79 in vitro and mice micronucleus in vivo test). The results showed that the cooking fume contained mutagenic activity. In the presence of S9 mix, an increase in the number of the Salmonella TA98 was observed at doses ranging from 1.0 to 5.0 mg/plate, and the SCE frequencies of V79 cell were markedly raised at doses ranging from 0.05 to 0.5 mg.ml-1. The positive result was also obtained in mice micronucleus assay, the mice had inhaled the cooking fume a week earlier. The frequency of mice bone marrow MN-PCE was increased and it showed a remarkable time-dose-response relationship during the 4 weeks exposure. The results suggested that this cooking fume exposure may be a risk factor of lung cancer in Chinese women.


Thyrotoxicity of the chlorides of cadmium and mercury in rabbit.

Exposure to heavy metals such as cadmium and mercury is of immediate environmental concern. The present study was aimed at establishing a direct relationship between heavy metal poisoning and thyroid dysfunction. Cadmium and mercury treatment at LD50 levels resulted in severe thyrotoxicosis in the rabbit. Within 24 h of intramuscular administration of cadmium chloride 15 mg.kg-1 body weight (bw) and mercury chloride 20 mg.kg-1 bw, thyroid peroxidase activity increased significantly over the control with a concomitant rise in the triiodothyronine (T3) titre. On the other hand, there was a remarkable fall in the thyroxine (T4) level, and the T3/T4 ratio was high as compared with the control. Evidence indicates that acute heavy metal lethality will induce immediate hyperthyroidism. It is suggested that T3-toxicosis may be produced by a preferential synthesis of T3 and/or preferential deiodination of T4 to T3. Measurement of T3 and T4 levels may thus be utilized as a reliable indicator of heavy metal lethality.


Metal induced inhibition of photosynthesis, photosynthetic electron transport chain and ATP content of Anabaena doliolum and Chlorella vulgaris: interaction with exogenous ATP.

This study demonstrates a concentration dependent inhibition of carbon fixation, O2 evolution, photosynthetic electron transport chain and ATP content of A. doliolum and C. vulgaris by Cu, Ni and Fe. Although the mode of inhibition of photosynthetic electron transport chain of both the algae was similar, PS II depicted greater sensitivity to the test metals used. The toxicity in both organisms was Cu > Ni > Fe. A. doliolum was, however, more sensitive to Cu and Ni, and C. vulgaris to Fe. Toxicity was generally dependent on metal uptake, which in turn was dependent on their concentrations in the external medium. A partial restoration of nutrient uptake, carbon fixation, and enzyme activities following supplementation of exogenous ATP suggests that ATP regulates toxicity through chelation.


An out-break of epidemic dropsy in the Barabanki District of Uttar Pradesh, India: a limited trial for the scope of antioxidants in the management of symptoms.

An attempt was made to explore the scope of the bio-antioxidants in the management of symptoms of epidemic dropsy caused by argemone alkaloids, sanguinarine and dihydrosanguinarine. The study was performed on 24 randomly selected epidemic dropsy cases who consumed argemone contaminated mustard oil. On examination the cases revealed characteristic pitting edema over limbs (95.8%) accompanied by tenderness (79.2%) and diffuse erythema (95.8%). Tachycardia was present in 1/3 of the examined cases while elevated jugular venous pressure was seen in over 40% of the cases. In two of the cases, reddish-purplish blotches over lower limbs, not raised and which blanched on pressure, was an unusual feature. Chest X-ray revealed pulmonary congestion in 5 cases. ECG performed in 3 cases with severe breathlessness, showed non-specific ST-T changes most marked in L2,L3, avF and V2-V6 which reversed on recovery. Treatment with a combination of antioxidants, riboflavin and tocopherol showed improvement in pain in lower limbs (75%), edema (83.3%) and erythema (66.6%).


Studies of lead exposure on reproductive system: a review of work in China.

This paper, based on a review of a series studies conducted in China from 1978 through 1991, describes the possible links between low level lead exposure and the adverse effects on reproductive system. Effects on menstrual status and pregnancy outcome manifested mainly as higher prevalences of menstrual disturbance, spontaneous abortion and threatened abortion in exposed females. Transfer of lead via placenta and human milk was shown by higher lead levels in milk and blood of infant. Impairment of male reproductive function was observed as decreased volume of ejaculation, prolonged latency of semen melting, reduced total sperm count and alive spermatozoa, retarded sperm activity as well as lowered density of semen fluid in exposed male workers with Pb-B over 40 micrograms.dl-1. In addition, poorer performance of WISC-R test was revealed in children with Pb-B level over 30 micrograms.dl-1, and retarded physical development was observed in children with Pb-B over 20 micrograms.dl-1. Therefore, health surveillance including the assessment of adverse effects on reproductive system of both female and male lead exposed workers should not be ignored. Furthermore, safety exposure limit of work place, particularly for female workers of child-bearing age, should be developed.


Total overall management and surgical outcome after aneurysmal subarachnoid haemorrhage in a defined population.

It was possible from a geographically well-defined region to detect all patients sustaining an aneurysmal subarachnoid haemorrhage. Different outcomes were measured and compared with other published series. Twenty-one per cent of all our patients at risk were never seen by a neurosurgeon. By adding further 20% of dead patients to the management series a total overall outcome, i.e. from all 'patients at risk', could be calculated, making comparison between different series easier. Favourable outcomes in the three groups (total overall, total management and surgical) as measured with the Glasgow Outcome Scale at 12 months were 46, 58 and 69%, respectively, in this series. In a super selected group such as good-grade patients (Hunt and Hess I-II) at surgery favourable results were seen in 87% of the patients at 6 months follow-up. The favourable outcome in the total overall, total management and surgical groups increased between 6 and 12 months follow-up by 1, 1 and 2%, respectively, as compared to 4, 5 and 6%, respectively, between discharge and 6 months follow-up. The time of follow-up to measure outcome should not be shorter than 6 months in aneurysm cases. It is emphasized that all patients drop-outs from the initial 'patient at risk' should be identified.


Smoking and subarachnoid haemorrhage: a case control study.

Retrospective and epidemiological studies have suggested that smoking increases the risk of developing aneurysmal subarachnoid haemorrhage (SAH). During 1990, 217 patients presenting to the Mersey Regional Neurosurgical unit with spontaneous SAH were prospectively studied. Smoking habits of patients with SAH were compared with age, sex and occupation matched controls. The relative risk of spontaneous aneurysmal SAH for smokers was twice that of non-smokers (p < 0.001). Management outcome at 6 months following aneurysmal SAH was similar for smokers and non-smokers (p = 0.43) but smokers had more postoperative pulmonary complications requiring ventilation. Significance was tested with chi-square tests.


Interstitial white matter brain oedema does not alter the electroencephalogram.

An experimental study was performed to determine the effects of interstitial white mater oedema on the electroencephalogram (EEG). Using both rodent and feline infusion models of focal brain oedema no difference was found between the EEG waveforms recorded epidurally from the infused and control hemispheres. It is concluded that where focal slow-wave EEG abnormalities overlie oedematous brain the EEG abnormalities are not primarily related to the brain oedema but arise from either local biomechanical or other pathophysiological mechanisms.


Effect of unilateral pre- and postganglionic lesioning of the trigeminal nerve on the development of cerebral vasospasm in the squirrel monkey: angiographic findings.

Bilateral carotid angiography was performed in the squirrel monkey before and after unilateral pre- and postganglionic trigeminal lesioning. A unilateral postganglionic lesion caused a significant constriction of about 27% of the ipsilateral cerebral arteries, while a preganglionic lesion did not change the baseline arterial diameter. Following a subarachnoid haemorrhage (SAH) the degree of vasoconstriction in the animals with a preganglionic lesion did not differ significantly from that seen in controls. In the postganglionically lesioned animals, the vasoconstriction was more pronounced (12% at both 10 min and 6 days post SAH) on the lesioned as compared with the non-lesioned side. At day 6 post SAH the degree of vasoconstriction was 19% more pronounced on the lesioned side in post- as compared with the preganglionically lesioned animals. There was no difference in the degree of spasm on the non-lesioned side between the two groups. The findings indicate that the trigeminal system has both a peripheral and a central function. The peripheral, or axon reflex mechanism, exerts a tonic effect on the cerebral vessels. Following a SAH the axon reflex seems to attenuate cerebral vasospasm.


Hyponatraemia in neurosurgical patients: diagnosis using derived parameters of sodium and water homeostasis.

Seventeen unselected, consecutive patients with intracranial disease and accompanying hyponatraemia were studied. All would previously have been diagnosed as having the syndrome of inappropriate antidiuretic hormone (ADH) secretion on the basis of spot plasma/urinary electrolyte testing with the application to them of existing standard laboratory criteria. Timed urinary collections and matching plasma samples were available in all but three cases for the derivation of creatinine, osmotic and free-water clearances, tubular reabsorbed water, and fractional water and sodium excretions. In a number of patients the plasma renin, aldosterone and ADH levels were also assayed. On the basis of the overall findings, 13 patients were diagnosed as in fact having a salt-wasting state whilst in only four patients was the diagnosis of inappropriate ADH secretion (SIADH) substantiated. It is suggested that obtaining simple derived parameters of sodium and water homeostasis can add significantly in differentiating between these quite opposite syndromes.


Microsurgical management of craniopharyngiomas.

A retrospective analysis of 34 patients who underwent microsurgical therapy for craniopharyngioma from 1975 to 1989, a period when CT imaging was routinely used, is presented. Mean follow-up was 6.4 years with no patients lost to follow-up. Those who underwent subtotal resection with adjuvant radiation had a significantly better recurrence-free interval compared with those who either underwent total or subtotal surgical resection only (p < 0.05 and p < 0.025). Among patients treated with surgery alone, the total resection group had a recurrence rate of 20% and those with a subtotal resection 60%. Those with subtotal resection and radiation had a 12% rate of recurrence. Endocrine and visual deficits were common after surgery. Based on this review, our results suggest that with a policy of attempted total resection where possible, subtotal removal along with adjuvant radiation, in cases where total resection was deemed unsafe, may be more effective than aggressive total resection alone as the initial management of craniopharyngioma.


A simplified technique for lengthening peritoneal catheters.

Existing techniques for lengthening a peritoneal catheter require a formal laparotomy, and exploration for the catheter which is then extended by the addition of a necessary length. We describe a simplified technique which is quicker and which in co-operative patients can be done under local anaesthesia on an out-patient basis. In this technique the peritoneal catheter along with its fibrous sheath is dissected and after opening the sheath an additional length is added. The elongated catheter is replaced through the same tubular sheath into the peritoneal cavity.


Cystic cerebellar schwannoma.

Cystic cerebellar schwannoma is a rare tumour which may not be considered when a low attenuation computed tomographic (CT) lesion is seen in the cerebellar parenchyma. Since the origin of the Schwann cell in the cerebellar parenchyma is conjectural, immunohistochemical techniques are necessary for a diagnosis.


MRI in the diagnosis of spinal extradural angiolipoma.

We report the case of a 68-year-old woman with a 1-year history of progressive spastic paraparesis, due to an extradural angiolipoma of the mid-thoracic spine. The MRI appearance of the angiolipoma is reported here for the first time. This appearance is characteristic, allows preoperative diagnosis and assists planning of the surgical approach.


Cerebral infarction due to Aspergillus arteritis following glioma surgery.

Cerebral infarction due to fungal arteritis is an uncommon complication of neurosurgical operations and adjuvant immunosuppressive therapy, including long-term steroids. If unrecognized, the neurological deterioration which ensues may be mistreated by increasing the dose of steroids. A case of a 38-year-old Caucasian male who had no obvious immune deficiency or fungal infection prior to a craniotomy for cerebral tumour is described in whom perioperative aspergillus infection resulted in cerebral arteritis and extensive cerebral infarction with a fatal outcome. Long-term steroid therapy used in the management of cerebral tumours may carry an increased risk of systemic or cerebral fungal infection. The possibility of cerebral mycosis (arteritis) and dangers of its non-recognition are highlighted.


Vein of Galen aneurysm presenting in middle age.

A vein of Galen aneurysm occurring in a 55-year-old woman is presented. The pathogenesis and treatment of this condition, which is rare in adults, is discussed and the literature reviewed.


Multicentric glioma of the spinal cord.

A 24-year-old woman with neurofibromatosis presented with a 1.5-year history of pain in the neck, both shoulders and back, and a 4-month history of progressively increasing weakness of all the limbs and inability to walk. The limb weakness fluctuated and, at the height of the weakness, it was associated with hesitancy and retention of urine. Magnetic resonance imaging (MRI) showed a fusiform enlargement of the upper cervical cord with obliteration of the subarachnoid space. Imaging after gadolinium-DTPA injection revealed inhomogeneous enhancement extending from the lower medulla down to the C4 cord level, and homogeneous enhancement at D3 to D4 and D6 to D8 cord levels. The spinal cord at the lower two levels appeared morphologically normal. At operation the fusiform enlargement of the cervical cord was confirmed. The tumour was partially removed. Histology revealed it to be a fibrillary astrocytoma.


Tinnitus suppression following cochlear implantation. A multifactorial investigation.

The effects of cochlear implant on loudness, annoyance, daily duration, location, and residual inhibition of tinnitus were evaluated by a closed-ended, quantifiable questionnaire in 33 postlingually deafened patients who had received implants at the University of Michigan, Ann Arbor, between 1986 and 1990. Preoperative tinnitus was present in 85% of patients. A statistical comparison of preoperative vs postoperative loudness and annoyance indicated a significant reduction in both of these complaints postoperatively. Loudness and annoyance were significantly correlated, both preoperatively and postoperatively. Fifteen patients (54%) with preoperative tinnitus demonstrated a loudness decrease of 30% or more; 43% demonstrated an annoyance decrease of 30% or more; and 48% demonstrated a decrease of 30% or more in daily tinnitus duration. Patients who experienced a loudness or annoyance decrease of 30% or more after implantation demonstrated significantly higher preoperative levels of these complaints, suggesting that degree of tinnitus reduction after implantation may be related to preoperative loudness and annoyance levels. Contralateral tinnitus suppression was reported by 42% of patients. Residual inhibition ranging from 60 seconds to several hours was reported by 50% of patients, predominantly in the ear with the implant. Age, gender, cause of hearing loss, duration of tinnitus, cochlear implant usage, and time after implantation were not predictive of tinnitus suppression. Overall, the majority of the patients (74%) thought that their cochlear implant was helpful in tinnitus suppression, especially in the ear with the implant. Contralateral residual inhibition and tinnitus suppression suggest a central mechanism contributing to these phenomena.


Mechanisms of retraction pocket formation in the pediatric tympanic membrane.

The epidemiological nature of acquired cholesteatoma in children has shown that it occurs more often in the posterosuperior quadrant of the pars tensa and in the pars flaccida. This type of cholesteatoma is rarely seen before the age of 3 years, and serous otitis media is the most important risk factor for its occurrence. In an attempt to present a pathological rationale for these clinical findings, tympanic membranes from 11 temporal bones with purulent otitis media and 13 with serous otitis media were evaluated light microscopically and compared with 14 temporal bones without disease. Ages ranged from newborn to 3 years 6 months. The persistence of mesenchyme and greater inflammatory reaction observed in the pars flaccida and the posterosuperior quadrant of the pars tensa and changes in collagen and elastin observed in purulent otitis media and serous otitis media may represent a pathological rationale for the epidemiological nature of cholesteatoma in children.


Screening audiometry using the high-risk register in a level III nursery.

Several factors, including those in the high-risk register, were studied in 1240 graduates of an intensive care nursery who underwent auditory brain-stem response testing. Univariate analysis, with chi 2 and Fisher's Exact Test, and stepwise logistic regression were used to identify variables associated with auditory brain-stem response outcomes. Results suggest that factors in the high-risk register do not carry equal weight and that universal screening in the intensive care nursery may be preferable.


Carboplatin-radiation interaction in squamous cell carcinoma cell lines.

Chemoradiotherapy has been considered one of the most promising improvements in the treatment of advanced head and neck cancer. This article describes in vitro chemosensitivity to carboplatin in five squamous cell carcinoma cell lines established from head and neck cancers and in one vulvar squamous cell carcinoma cell line. Sensitivity to carboplatin was found to vary markedly when using the 96-well plate clonogenic assay and continuous drug exposure. The difference in carboplatin response between the most sensitive and the most resistant cell lines was fourfold. No cross-resistance was observed between inherent radiosensitivity and chemosensitivity. Effects of concomitant use of carboplatin and radiation were further investigated in the two cell lines that were found to be most sensitive to carboplatin. The drug was administered 1 hour before acute radiation doses, and an additive effect was observed in both cell lines.


Analysis of laryngeal movement by digital subtraction laryngography.

Fine movement of laryngeal components was analyzed by digital subtraction laryngography with the use of a digital fluorography system. Two kinds of image processing modes, the super pulse image subtraction mode and the time interval difference mode, were used for this purpose. By the super pulse image mode, the distance and extent of movement of laryngeal components at vocal initiation and during phonation could be observed. By the time interval difference mode, the amount and direction of motion for a certain interval and fine movement, such as vocal initiation, were determined.


Cytogenetic alterations in laryngeal carcinomas.

The purpose of this study was to determine the most frequent chromosomal abnormalities in laryngeal carcinomas. Biopsy specimens of surgical resections from laryngeal squamous cell carcinomas from 15 patients representing different degrees of histologic differentiation were analyzed in short-term culture. Nine of the 15 tumors were hypodiploid with 41 to 45 chromosomes, and four of the 15 tumors were polyploid with more than 50 chromosomes. The most frequent chromosomal alterations we noted included deletion of the short arm of chromosome 3 in 60%, monosomy of chromosome 11 in 30%, and inversions of chromosome 9 and 16 that were present in 20% of the cases.


Should granulomas be excised in children with long-term tracheotomy?

We reviewed 265 rigid bronchoscopies performed in 50 children with tracheotomy-dependent subglottic stenosis (25 congenital, 25 acquired). Granulomas developed in 40 children (80%) and were unrelated to age, sex, race, gastroesophageal reflux, tracheotomy duration, or type of stenosis. The incidence of small to medium, large, and obstructing granulomas at endoscopy was 28%, 6%, and 0%, respectively. Compared with a baseline finding of no granuloma at preceding bronchoscopy, the odds of granuloma recurrence were 3.0 after an unexcised granuloma (95% confidence interval [CI], 1.1 to 8.4), 4.1 after granuloma excision (95% CI, 1.4 to 11.9), and 7.3 after expansion surgery (95% CI, 1.1 to 49.2). Considering the low incidence of large or obstructing granulomas, and the failure of granuloma excision to diminish recurrence, we do not recommend interval excision of nonobstructing granulomas in children with stable tracheotomies.


Postoperative technetium scanning in patients with submandibular duct diversion.

Submandibular duct diversion is a common procedure for refractory sialorrhea in children. The procedure reroutes Wharton's ducts from the floor of the mouth to the tongue base. As the majority of saliva in the resting state is produced by the submandibular glands, rerouting markedly decreases sialorrhea. However, the procedure has been criticized in that diversion may cause fibrosis and stricture of the ducts. The gland would atrophy, and the physiologic functions of saliva would be lost. Glandular function of six patients with cerebral palsy (mean age, 14.7 years) was evaluated by technetium scanning (mean time after surgery, 43 months). Four patients had normal bilateral function; two patients had no function in one gland but normal function in the contralateral gland. We conclude that bilateral submandibular duct diversion maintains long-term function in at least one gland.


Needle-wire localization of an infratemporal fossa foreign body using computed tomography.

We report a case involving the localization and surgical removal of a traumatically introduced foreign body deep within the infratemporal fossa. Needle-hookwire placement with computed tomographic guidance allowed the precise localization and marking of the foreign body. Surgical removal under local anesthesia and without extensive exploration was, therefore, possible. The details of the localization and marking techniques are described. Needle-hookwire localization under computed tomographic guidance should be considered for deeply located foreign bodies in the head and neck area.


Primary carcinoid tumors of the middle ear. Report on four cases and a review of the literature.

Carcinoid tumors are rare in the middle ear. To our knowledge, only 17 cases could be found in the literature, the first of which was described in 1980. In addition to enlarging on a previous observation we present three new cases. The neoplasms showed a striking, heterogeneous aspect ranging from solid trabecular to tubuloglandular growth patterns resembling the classic carcinoid tumor and adenomatous middle ear tumor, respectively. Based on immunohistochemistry and electron microscopy, three cell types were found. A review was made of our four patients and the cases described in the literature. The medical histories ranged from 1 month to 9 years. Presenting symptoms and signs were not characteristics, but hearing loss predominated. In two patients, the eardrums were perforated, in all the others it was intact and often bulging. Surgery, usually radical mastoidectomy, was performed in all cases. Often the tumor encased the ossicular chain, without infiltration. In two patients, local recurrence occurred that was treated successfully with surgery. All the cases showed an indolent biological course and the tumors were clinically nonfunctional, despite the recognition of biogenically active products by immunohistochemistry. To our knowledge, regional or distant metastases have never been reported. Conservative surgery with radical removal of the primary or recurrent tumor is the treatment of choice.


Transoral surgical management of lesions of the base of the tongue.

Lesions of the base of the tongue are rare in the pediatric population. However, when present these lesions may lead to airway obstruction and feeding difficulties. Two patients with lesions of the base of the tongue are described to demonstrate the diagnosis and management of this difficult clinical problem. The use of a transoral median glossotomy for total excision of these lesions is advised in this article. This approach affords excellent surgical exposure, early return to a normal diet, and lack of facial scars.


Dolichol: a curriculum cognitionis.

Dolichols were first described about 30 years ago when animal tissues were being examined for the presence of a putative precursor to the polyisoprenoid side chain of ubiquinone. These long-chain 2,3-dihydro-polycis-isoprenoid alcohols are found in all eukaryotic organisms. In many plant tissues they are accompanied by families of other polyisoprenoid alcohols that are usually similar molecules and possess an unsaturated alpha-isoprene residue. Analogy with the role of bactoprenyl phosphates in the synthesis of bacterial wall glycans led to the discovery that the mono- and di-phosphates of dolichols function as cofactors in protein N-glycosylation, involving the formation of glycosylated derivatives of dolichol as intermediates. Variation of the concentration of dolichyl phosphate was shown to be one way of controlling protein N-glycosylation. This can be achieved by modification of the relative activities of dolichol kinase and dolichol phosphate phosphatase. Modulation of the biosynthetic pathway, still not fully understood, of dolichyl phosphate may also be an important factor. Several disease conditions involve aberrations in these pathways.


Dolichol: function, metabolism, and accumulation in human tissues.

Dolichol, a homologous series of alpha-saturated polyisoprenoid alcohols containing 14-24 isoprene units, was first isolated and characterized about 30 years ago. The phosphorylated form, dolichyl phosphate, is required for the biosynthesis of biologically important N-linked glycoproteins. Dolichol itself is synthesized by a common isoprenoid pathway from acetate and synthesis can be inhibited by some of the factors that inhibit cholesterol biosynthesis. It is metabolized very slowly and accumulates in tissues during aging and in certain lipid storage diseases. Dolichyl phosphate and cholesterol also accumulate in tissues during aging, but to a lesser extent than dolichol. Although dolichol and cholesterol have important metabolic functions, their accumulation in tissues can have deleterious effects.


Dolichol metabolism in Chinese hamster ovary cells.

The addition of oligosaccharide to asparagine residues of soluble and membrane-associated proteins in eukaryotic cells involves a polyisoprenoid lipid carrier, dolichol. In Chinese hamster ovary cells, the major isomer of this polyisoprenol has 19 isoprenyl units, the terminal one being saturated. Our laboratory has developed a procedure to analyze the levels and nature of the cell's dolichyl derivatives. Chinese hamster ovary cells contain predominately activated, anionic dolichol derivatives, such as oligosaccharyl pyrophosphoryldolichol, monoglycosylated phosphoryldolichols, and dolichyl phosphate. Our studies show that in growing cells there is continual synthesis of total dolichol. Also, preliminary data suggest there is no catabolism or secretion of this lipid. The level of dolichyl phosphate did not change significantly under a variety of conditions where the levels of enzyme activities utilizing dolichyl phosphate did change. These results suggested that these enzymes had access to the same pool of dolichyl phosphate and had similar Km values for this lipid.


The importance of N-linked glycoproteins and dolichyl phosphate synthesis for fusion of L6 myoblasts.

Myoblasts fuse to form multinucleated myotubes, one of the early steps in the formation of multinucleated muscle fiber. The fusion reaction is accompanied by biochemical differentiation resulting in the expression of a variety of enzyme activities and macromolecules, particularly creatine phosphokinase. The fusing myoblast is thus an excellent system for use in studies on the molecular basis of cellular recognition. This report focuses on the role played by glycoproteins in this process. It was found that alteration of cell-surface glycoproteins, using oligosaccharide-processing inhibitors that interfered with the synthesis of the high-mannose type of N-linked oligosaccharide, resulted in the inhibition of both the fusion reaction and biochemical differentiation as determined by measurement of creatine phosphokinase. Ketoconazole, compactin, and lovastatin, which affect dolichol and cholesterol biosynthesis, were also potent fusion inhibitors. These observations, coupled with earlier studies on the characterization of fusion-defective myoblast cell lines defective in glycoprotein biosynthesis, point to the importance of surface glycoproteins in cellular recognition in L6 myoblasts.


Ubiquinone, dolichol, and cholesterol metabolism in aging and Alzheimer's disease.

The lipid compositions of various regions of the human brain were investigated during aging and in Alzheimer's disease. The phospholipid amounts and compositions remained unchanged during aging. There were, however, considerable differences both in phospholipid composition and amount when the various regions were compared. The level of dolichol increased severalfold in all regions up to the age of 70, but there was no further elevation thereafter. The ubiquinone level decreased significantly in all parts of the brain upon aging. In Alzheimer's disease, the dolichol level was decreased in all regions, and particularly, in those affected by the disease. In contrast, the dolichyl-P concentration increased in those regions that exhibited morphological changes. There was no modification in cholesterol distribution, but a significant elevation in ubiquinone content was observed in most regions. The only phospholipid whose level was elevated was phosphatidylinositol, and only in those parts of the brain that were affected. The content of polyunsaturated fatty acids in phosphatidylethanolamine was greatly decreased in connection with the disease, with a parallel increase in the saturated portion. The results indicate that Alzheimer's disease results in specific and significant changes in the levels of lipid products of the mevalonate pathway in the brain.


New developments in the synthesis of phosphopolyprenols and their glycosyl esters.

Efficient methods were developed in our group in recent years for chemical synthesis of polyprenyl phosphates, polyprenyl monophosphate sugars, and polyprenyl diphosphate sugars, which were known to serve as important intermediates in biosynthesis of complex carbohydrates. A simple procedure was developed involving the phosphorylation of aliphatic alcohols with tetra-n-butylammonium dihydrogen phosphate and trichloroacetonitrile. Monophosphates of various natural and modified dolichols and polyprenols, as well as the derivatives of retinol, cholesterol, and nonacosanol, were prepared in high yields. First syntheses of dolichyl thiophosphate and dolichyl hydrogen phosphonate were developed, and these derivatives were of interest as analogs of dolichyl phosphate. Polyprenyl monophosphate sugars, including derivatives of alpha- and beta-anomers of D-glucopyranose, D-galactopyranose, D-mannopyranose, and 2-acetamido-2-deoxy-D-glucopyranose, were obtained smoothly from moraprenyl trichloroacetimidate and acylated glycosyl phosphates after deprotection. A method for the synthesis of polyprenyl diphosphate sugars from polyprenyl phosphoroimidazolidate and unprotected glycosyl phosphates was shown to be applicable for a wide range of the monosaccharide derivatives including hexoses, deoxyhexoses, 2-acetamido-2-deoxyhexoses, and uronic acids. A series of the oligosaccharide derivatives was also prepared by this method.


The occurrence of long chain polyprenols in leaves of plants of Rosaceae family and their isolation by time-extended liquid chromatography.

The long chain polyprenols composed of 30 and more isoprene units from leaves of plants belonging to the genera Potentilla and Rosa have been described. They occur in the form of fatty acid esters. The composition of polyprenol mixture was species dependent and its content reached ca. 0.5% wet weight. Large scale preparation of individual polyprenols from a natural polyprenol mixture was performed using time-extended liquid chromatography on the hydrophobic gel Lipidex-5000.


Yeast dolichyl-phosphomannose synthase: reconstitution of enzyme activity with phospholipids.

The activity of purified recombinant yeast dolichyl-phosphomannose synthase (EC 2.4.1.83) was assessed following reconstitution of the enzyme with phospholipids. The yeast synthase, similar to the mammalian enzyme, was active when reconstituted with phosphatidylethanolamine dispersions but had little (less than 5%) activity in stable phosphatidylcholine bilayers. The enzyme was activated by adding increasing amounts of diacylglycerol to phospholipid bilayers, suggesting that activity of the yeast enzyme was dependent on lipid phase properties rather than specific phospholipids. The synthase could also be reconstituted as an active enzyme in bilayers prepared with a commercial crude lipid preparation containing 40% phosphatidylcholine, but at a rate 10% of that occurring in phosphatidylethanolamine. Vesicles composed of the 40% phosphatidylcholine lipid mixture, dolichyl phosphate, and enzyme were leaky in the presence of divalent cations, and dolichyl-phosphomannose synthase did not appear to catalyze the translocation of dolichyl phosphomannose across membranes at a catalytically significant rate under the assay conditions employed.


Changes of dolichol and dolichyl fatty acyl esters during the germination and development of soybeans.

The amounts of dolichol and dolichyl fatty acyl esters and their composition in various parts of soybean seedlings were determined during germination and development. The dolichol content of cotyledons decreased during germination. Dolichyl fatty acyl esters were identified in cotyledons and the amount was estimated by high performance liquid chromatography. The relative amounts of short-chain dolichols of 15, 16, and 17 isoprene units increased during development of the seedlings. The homologue distribution of free dolichol was different from that of dolichyl fatty acyl esters. The relative amounts of dolichols with 16, 17, and 18 isoprene units were greater in free dolichol than in dolichyl fatty acyl esters. The percentages of long-chain saturated fatty acids in dolichyl fatty acyl esters, specifically 21:0, 22:0, 23:0, 24:0, and 25:0, increased during development. These fatty acids represented more than 40% of the fatty acids in dolichyl fatty acyl esters in stems. These results suggest that dolichyl fatty acyl esters are not a storage form of dolichol. The large accumulation of dolichol and dolichyl fatty acyl esters in the leaves, where photosynthesis takes place, suggests some other function.