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Biomedical subjects

P Langer

Publications and source records attributed to P Langer.

At least 109 records · Page 6Linked to original sources
PubMed1993

The gastric groove, a specific adaptation to nutritional ontogeny in eutherian mammals.

In this paper grooves or groove-like structures along the lesser gastric curvature in 19 eutherian mammal species are classified according to their muscular architecture and according to mucosal differentiations. It is shown that the differentiations along the lesser curvature represent morphological and functional links between the length of lactation and weaning times, on the one hand, and the types of digestion applied by the adult animal, on the other.

Adaptation, Physiological↗
PubMed1992

Cloning of human tumor cell lines in porous glass capillary tubes: a further development of the human tumor stem cell assay.

The conventional human tumor stem cell assay for cloning tumor cells for drug sensitivity testing is limited by its inability to test drug combinations. In an attempt to overcome this limitation, we cloned tumor cell lines within porous glass capillary tubes. In contrast to plastic porous tubes, the porous glass membranes were transparent, and colony formation could be judged on an inverted microscope. Human as well as animal cell lines showed sufficient colony growth. Colonies formed within these porous tubes were homogeneously distributed, and their morphology was similar to those formed in the common stem cell assay. Cloning efficiency and colony size depended on the mean pore diameter of the glass membrane, with best colony growth within tubes with a pore diameter ranging from 8.5 nm to 14 nm. A linear relationship between number of cells seeded and number of grown colonies could be demonstrated for the cell lines MDA-231 and Colo 201. Colony growth achieved within porous glass capillary tubes is comparable to that achieved in Petri dishes and in nonporous tubes. We conclude that the porous capillary cloning system meets the basic suppositions for a quantitative cloning assay. Moreover, the porosity of the glass membrane offers the possibility of variable perfusion of medium and drugs. Further investigations will focus on various perfusion modalities and chemosensitivity testing.

Animals↗
PubMed1992

Immediate and dose-response related increase of biliary excretion of reverse triiodothyronine after propylthiouracil administration.

In a group of rats infused with L-thyroxine (0.13 micrograms T4 in 0.6 ml alkaline saline per hour) for 6 h to which an infusion of propylthiouracil (PTU) was added beginning from the 3rd hour (2 mg PTU in 0.6 ml saline per hour) a significant increase of biliary excretion of reverse triiodothyronine (rT3) was found. In another experiment a dose-response related rT3 excretion by bile was observed in groups of rats infused with 0.05, 0.10, 0.20 or 0.40 mg PTU in 1.2 ml alkaline saline per 2 h, all animals receiving a pulse dose of 1 micrograms rT3 at the beginning of PTU infusion. It was concluded that the increase of rT3 excretion results from the inhibition of 5'-deiodinase type I activity in the liver caused by PTU. It thus appears that such phenomenon may be used as in vivo marker of that enzyme activity.

Animals↗
PubMed1992

Acute development of low T3 syndrome and changes in pituitary-adrenocortical function after elective cholecystectomy in women: some differences between young and elderly patients.

From two groups of female patients (young group: 15 patients aged less than 25 years; elderly group: 15 patients aged more than 65 years) who were subjected to cholecystectomy, blood samples were obtained on the day before surgery, on the day of surgery before premedication and after waking up from anaesthesia and also on days 1, 3 and 7 after surgery. In aliquots of sera the levels of TSH, ACTH, thyroxine (T4), triiodothyronine (T3), reverse triiodothyronine (rT3) and cortisol were estimated with the aid of radio-immunoassay (RIA). The differences between the young and elderly subjects were evaluated with the aid of four different statistical tests. Though no changes in the level of T4 were found, the level of T3 was significantly decreased and that of rT3 was significantly increased on Day 1 after surgery. However, the decrease of T3 was expressed more significantly in the young group and, in addition, an increase of rT3 in the same group was found even before premedication. The level of TSH showed a sharp increase at the end of surgery, which was expressed more in the young group. Though no differences between groups were observed in a sharp peak of the ACTH level during surgery, the increase of cortisol level in the elderly group was significantly higher and remained so during the post-operative period.

Adrenocorticotropic Hormone↗
PubMed1992

[The importance of optimal iodine intake, the present status and perspectives in Slovakia].

The concentration of iodine was estimated in 667 urine specimens of boys and girls aged 6-18 years from 5 regions of Slovakia. Only about a half of all values (i.e. 48.43%) was found in the optimum range of 10-20 micrograms/dl, while 40.43% of values wore in the range of iodine deficiency (i.e. less than 10 mu/dl). In addition, there were 10.64% of high values (ie. more than 20 micrograms/dl). These results show that the intake of iodine appears to be 3-4 times higher than before the start of iodine prophylaxis in about 1950, but it still does not reach the optimum level. The increase of iodine intake would be achieved by the replacement of iodide (KI) with iodate (KIO3) which is much more stable. This prevents the looses of iodine from the salt which represent 50 to 75 percent of the original level within 1 to 1 and a half year.

Adolescent↗
PubMed1991

Partial hepatectomy alters serum hormone levels in rats.

The level of thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), thyroxine (T4), 3,5,3'-L-triiodothyronine (T3), corticosterone, testosterone and insulin in serum were measured at 1, 12, 48 and 120 h after partial hepatectomy (PH) or sham operation in rats. After PH the level of ACTH and corticosterone was significantly elevated while that of TSH, T4 and testosterone was decreased and returned to the values found in sham operated animals within 5 days. The level of T3 was unchanged. These results show an increase in the function of pituitary-adrenal axis and a decrease in that of pituitary-thyroid axis shortly following PH with the tendency to return to normal function within five days.

Adrenocorticotropic Hormone↗
PubMed1991

Increase of biliary excretion of reverse triiodothyronine in rats during the infusion of neurotensin possibly resulting from the inhibition of iodothyronine 5'-monodeiodination.

Male rats weighing about 350 g were inserted polyethylene tubes into the bile duct and femoral vein under pentobarbital anaesthesia. After taking the first (control) 2-h bile sample the control group (n = 24) was infused saline for 4 h and the other group (n = 14) was infused neurotensin in a dose of 27 micrograms per animal per 4 h. The concentration of thyroxine (T4), triiodothyronine (T3) and reverse triiodothyronine (rT3) in the bile was estimated by radioimmunoassay. No significant differences between groups were found in the biliary excretion of T4 and T3, while the excretion of rT3 after the infusion of neurotensin was significantly increased which was not the case in controls. Since neurotensin is known to increase glycemia which effect might be or might not be mediated by glucagon, it may be suggested that these results bring an additional support for the previously reported coincidence between a prevailing effect of gluconeogenetic hormones and inhibition of iodothyronine 5'-deiodination in the liver.

Animals↗
PubMed1990

Thyroid volume by ultrasound in boys and girls 6-16 years of age under marginal iodine deficiency as related to the age of puberty.

The results of thyroid volume estimation with the aid of ultrasound in a total of 921 boys and girls 6-16 years of age are reported. The thyroid volume was found to be increasing slowly between the age of 6 and 12 years, but somewhat more remarkable increase occurred at 13 and 14 years of age. However, in both sexes it was nearly doubled at the age of 15-16 years as compared with the values at 13-14 years irrespective of body weight. The thyroid growth rate (as calculated from the least squares analysis of the correlation between thyroid volume and body weight) in girls was significantly higher (P less than 0.001) than in boys. In spite of long-term mandatory iodine prophylaxis the average urinary excretion of iodine as estimated in 69 randomly selected subjects was 78.06 micrograms/g creatinine (geometrical mean). It may be suggested that such intake of iodine, though marginally deficient, may be satisfactory up to the age of about 12-14 years, while it appeared to be inadequate for the adolescents at the age of puberty.

Adolescent↗
PubMed1990

[Acute low triiodothyronine syndrome in the perioperative period].

Serum concentrations of thyroxine (T4), triiodothyronine (T3) and reverse triiodothyronine (rT3) were determined by radioimmunoassay in 11 patients (8 females and 3 males aged 42-65 years) before cholecystectomy and at various time intervals following operation up to 10 days. The surgical procedure was uncomplicated in all the cases studied. The level of rT3 was significantly increased (P less than 0.01) already on the first postoperative day and was then decreasing to its initial value. The levels of T4 and T3 were markedly reduced particularly on postoperative days 2 to 5 (the drop was significant on calculating individual values as percentages of the preoperative level of the given patient). This acutely developing syndrome of low triiodothyronine disappeared spontaneously within 7 to 10 days at a noncomplicated postoperative course.

Acute Disease↗
PubMed1989

Effect of the glycogenolytic gluconeogenetic hormones, glucagon, vasopressin and angiotensin II, on biliary excretion of iodothyronines in rats is possibly related to the inhibition of 5'-monodeiodination in the liver.

Polyethylene tubes were inserted into the bile duct and femoral vein of rats under pentobarbital anaesthesia and bile was collected for three 2-h periods. After the first (control) period the animals were infused intravenously at a rate of 1.2 ml/h with the following compounds: (1) 0.9% (w/v) NaCl (control group), (2) glucagon (1200 ng/h), (3) vasopressin (1200 ng/h) or (4) angiotensin II (600 ng/h). The concentrations of thyroxine (T4), tri-iodothyronine (T3) and reverse tri-iodothyronine (rT3) in the bile were estimated by radioimmunoassay. No significant differences between groups were found in the biliary excretion of T4 and T3, while the excretion of rT3 after the infusion of all the hormones used was significantly (P less than 0.001 at 2 to 4 h of the infusion) increased, no such increase being found in the controls. It may be concluded therefore that the administration of the above hormones resulted in some changes in iodothyronine metabolism in the liver. These may be explained by an inhibition of iodothyronine 5'-monodeiodination related to the glycogenolytic and gluconeogenetic effects of these hormones.

Angiotensin II↗
PubMed1989

Increased incidence of congenital hypothyroidism in Gypsies in east Slovakia as compared with white population.

Ethnic Gypsies represent 9 percent of total population of East Slovakia. However, during first three and half years of compulsory screening of congenital hypothyroidism (CH) there were 15,346 Gypsy newborns which was 16.8 percent of a total number of 90,760 newborns. Out of these Gypsy newborns 7 cases of CH were found (i.e. 1:2192), while 12 cases of CH were observed among 75,414 white newborns (i.e. 1:6284), which was significantly less than that in newborns Gypsies (P less than 0.05). Since the far highest coefficient of inbreeding ever reported for any European population or ethnic groups has been found by others in newborns Gypsies living in Slovakia (Fg = 0.017 obtained by genealogic method and Fi = 0.084 obtained by the method of isonymy), it may be suggested that a high incidence of CH in newborns Gypsies may be due to some genetic and hereditary factors. Though a direct interrelationship cannot be definitely established from the present data and still remains far from to be elucidated, the present observation may be considered as a contribution to the study of this problem.

Congenital Hypothyroidism↗
PubMed1989

Normal thyroid size versus goiter--postmortem thyroid weight and ultrasonographic volumetry versus physical examination.

The data on postmortem thyroid weight and on thyroid volume estimation with the aid of ultrasound are briefly reviewed and correlated with indicated or presumed intake of iodine in the appropriate area. The well known negative correlation between iodine intake and thyroid size may be supported even by this approach which shows that as a normal thyroid volume may be taken that obtained in areas with sufficient iodine intake such as Iceland, Sweden, Netherlands and USA. In these countries the average thyroid volume was found by various authors to be in a range of about 8 to 12 ml (or g) for females and about 11 to 15 ml (or g) in males which is approximately 10 ml (or g) less than the values considered as normal until recently. The comparisons of the data on postmortem weight or sonographically determined volume of the thyroid with palpatory findings showed that the same stage of thyroid size according to various recommended scales as found by palpation or inspection may correspond to a great variety of actual volumes and thus that the palpation may be considered as highly inaccurate method for precise estimation of thyroid size. From this view it may be recommended predominantly for large scale and low cost field epidemiological studies, while a most favourable ultrasonographic volumetry should be used for a majority of basal clinical studies and field surveys.

Adult↗
PubMed1989

Goiter prevalence and thyroid volume by ultrasonographic volumetry in two groups of schoolchildren and adolescents from east Slovakia.

Thyroid volume by ultrasonographic volumetry was estimated in a total of 427 boys and 425 girls aged 7 to 16 years from East Slovakia. It was found that the volume is increasing by age and body weight, being in average about 2.5 ml in 7-8 years old, 3.5 to 4.5 ml in 9-12 years old, 5.2-6.0 ml in 13-14 years old and, as reported previously, 11-12 ml in 15-16 years old. Comparing these results to the findings reported from other countries, it may be concluded that in 13-14 years old schoolchildren the thyroid volume was about twice as high as reported for the same age group from Sweden (with presumably sufficient iodine intake) and by about 20 percent less than found in 13 years old schoolchildren in Federal Republic of Germany (with insufficient iodine intake). The average thyroid volume found in pubertal adolescents aged 15-16 years closely resembled that found in Federal Republic of Germany and was even higher than that found in adults from Sweden and Netherlands where the iodine intake is considered to be sufficient. Palpatory findings according to WHO scale showed 21 percent of goiter stage 1a in boys aged 7-14 years and 24 percent in girls of the same age group, while such values were 23 and 27 percent for boys and girls aged 15 and 16 years, respectively. In addition, in those aged 15-16 years about 3 percent of goiter stage 1b were found, while in those aged 7-14 only 3 cases of goiter stage 1b out of 425 examined were observed. It may be concluded that the present status of thyroid size in examined group closely resembles the first grade endemy of goiter as defined recently by Hetzel and, moreover, it may be suggested that the intake of iodine about 100 micrograms daily (which was recently reported by other authors from Czechoslovakia as based on urinary excretion of iodine) apparently does not fully prevent the development of goiter stage 1 in a considerable amount of children and adolescents.

Adolescent↗
PubMed1989

[The low triiodothyronine syndrome--the cause or the result of a critical state?].

A comprehensive review of the deiodinating pathway of thyroxine (T4) metabolism including its conversion to triiodothyronine (T3) and reverse triiodothyronine (rT3) presented with special attention to intracellular events and their regulation. In addition, present knowledge on T3 syndrome in nonthyroidal diseases (definition, pathophysiology, clinical stages, differential diagnosis of thyroid disorders, treatment) is briefly reviewed. The question is being raised whether low T3 syndrome should be considered the consequence or rather the cause of critical stages of major nonthyroidal diseases. Though the view of some authors considering this syndrome a homeostatic mechanism enabling survival of the organism under critical conditions is fully observed, it is hypothesized that, under certain conditions, a stepwise decrease of T3 formation becomes irreversible. Considering the role of T3 in the expression of essential metabolic enzymes, such an irreversible stage may result in very unfavorable metabolic conditions of vital organs, an assumption supported by the high mortality rate of critically ill patients with very low plasma T3 and T4 levels reported by several authors. This problem warrants further attention involving attempts to find appropriate methods of treatment. Finally a brief review of the author's own experimental approach to the study of the regulation of T4 deiodination in rat liver in vivo based on the determination of billiary excretion of T4, T3 and rT3 by radioimmunoassay is presented. As published elsewhere, the excretion of rT3 was acutely increased after administration of adrenaline (which was mediated by alpha 1-adrenoceptors) and of other glycogenolytic and gluconeogenic hormones such as glucagon, vasopressin and angiotensin II. These findings lead to the conclusion that 5'-monodeiodination in the liver is inhibited under conditions of prevailing gluconeogenesis which may explain the decrease of T3 formation under fasting and under reduced caloric intake in severe nonthyroidal diseases. (Fig. 6, Ref. 64).

Humans↗
PubMed1989

Studies on congenital hypothyroidism and results of three and half years of compulsory screening program in Slovak Socialist Republic.

In the introduction the results of previous retrospective study (1975-79) including 312,259 newborns and of preliminary screening program including 31,780 newborns are briefly summarized. After January 1st, 1985 a compulsory screening of congenital hypothyroidism (CH) was started in the whole territory of Slovakia using the estimation of thyroxine in dry blood spot obtained from a heel prick on 5th day after birth. In suspected cases a complete clinical and laboratory examination was made including TSH estimation by RIA and after January 1st, 1988 by IRMA. The organization of screening program is described in detail. During three and half year period 286,469 newborns were examined which represented almost 100 percent of all newborns. A total of 44 cases of CH was found out of them 13 cases of athyreosis, 3 cases of ectopic thyroid and 28 cases of dyshormonogenesis (among them 5 cases with goiter and 23 cases without goiter). The average incidence of CH was 1:6874. Until January 1st, 1988 (when only T4 estimation was used as a first step) the recall rate was 2.32% and the treatment was started before 25th day after birth, while after the use of TSH by IRMA from dry blood spot in suspected cases (i.e. after January 1st, 1988) the recall rate decreased to 0.82% and the treatment was started before 14th day of life. In addition, the data on 39 cases of TBG deficiency and on regional differences in their incidence are reported. Some remarkable differences in the incidence of total CH and of its individual variants between West, Central and East Slovakia with different historical, cultural, economical and genetical background as well as in some ethnic groups (Gypsies) are also presented.

Congenital Hypothyroidism↗