Islet cell antibodies in the Japanese population and subjects with type 1 (insulin-dependent) diabetes

Islet cell antibodies were studied in 1,112 non-diabetic adults, 473 normal school children and 162 Type 1 (insulin-dependent) diabetic patients in a Japanese population. The prevalence of islet cell antibodies was 0.5%, 0.4% and 32%, respectively. Most islet cell antibodies positive subjects with Type 1 diabetes had short duration of the disease. No patients who had over 10 years from the onset had islet cell antibodies. Six non-diabetic adults with islet cell antibodies were followed for 4 years. Only one with Hashimoto's thyroiditis showed a diabetic pattern in her oral glucose tolerance test. However, none developed overt insulin-dependent diabetes until 1984. Two out of these six subjects continued to be positive for both islet cell antibodies and antithyroid antibodies or antinuclear antibodies. Islet cell antibodies in the remaining four patients disappeared during the second year. It is difficult to predict the onset of Type 1 diabetes by islet cell antibodies in non-diabetic individuals because they may be transient.

Effect of diabetes on triiodothyronine and reverse triiodothyronine production in the perfused rat liver and kidney

This study was undertaken to elucidate the effect of diabetes on the conversion of T4 to T3 and rT3 in the isolated, perfused rat liver and kidney. The livers and kidneys from streptozocin (STZ)-induced (50 mg/kg i.p. 2 wk before killing) diabetic rats with or without T4 (30 micrograms/kg s.c. daily) treatment were perfused for 30 min with a synthetic medium containing T4 (6 micrograms/dl), and production of T3 and rT3 in the tissues was measured by radioimmunoassay. The production of T3 (111 +/- 38 ng/g/30 min, mean +/- SD) and conversion rate of T4 to T3 (19.7 +/- 5.8%) in the liver of diabetic rats without T4 treatment and those (124 +/- 41 ng/g/30 min and 21.6 +/- 4.9%) in the liver of diabetic rats with T4 treatment were significantly lower than those of controls (196 +/- 48 ng/g/30 min and 30.6 +/- 5.2%), respectively. The production of rT3 and conversion rate of T4 to rT3 in the liver of diabetic rats with or without T4 treatment were similar to those of controls. The production of T3 and rT3, and conversion rate of T4 to T3 and T4 to rT3, in the kidney of diabetic rats with or without T4 treatment were not significantly different from those of controls. These results suggest that the liver is far more important than the kidney in the overall reduction in the T4 to T3 conversion that occurs in diabetic rats.

Structure of enoate reductase from a Clostridium tyrobutyricum (C. spec. La1)

Enoate reductase from Clostridium tyrobutyricum was purified by a rapid novel procedure. Chromatography on DEAE-Sepharose and on hydroxyapatite resulted in a high yield of about 90% pure enzyme in less than 10 h. A purity greater than 98% could be obtained by additional chromatography on Sephacryl S-300. The enzyme sediments in the analytical ultracentrifuge as a single, symmetrical boundary with a velocity of S(0)20,w = 24.9 S. Equilibrium ultracentrifugation yielded a molecular mass of 940 000 +/- 20 000 Da. The enzyme contains one type of subunit as shown by dodecyl sulfate electrophoresis and partial sequence determination. A subunit molecular mass of about 73 000 Da was established by dodecyl sulfate electrophoresis and by sedimentation equilibrium analysis in guanidine hydrochloride. In addition to FAD, iron and labile sulfur, the enzyme purified by the new method showed approximately 0.7 mol of FMN per mol of subunit. A dissociation product sedimenting at a velocity of S(0)20,w = 9.8 S can be obtained by various experimental protocols. The fragment was obtained in pure form by gel permeation chromatography. The molecular mass was 230 000 +/- 10 000 Da as shown by sedimentation equilibrium analysis. Thus it appears that the dissociation product is a trimer of the 73 000-Da subunit. The formation of the 10-S fragment by dissociation of the native enzyme is accompanied by the loss of most of the FMN, whereas the FAD content is not changed. The fragment catalysed the reduction of acetylpyridine adenine dinucleotide by NADH. However, enoate reductase activity with NADH or methylviologen as cosubstrate was low. Electron micrographs of negatively stained enoate reductase show trigonal symmetry. The data suggest that enoate reductase is a dodecamer (tetramer of trimers) with tetrahedral symmetry.

[Anti-triiodothyronine antibodies in patients with rheumatoid arthritis associated with Hashimoto's thyroiditis]

Anti-triiodothyronine antibody was found in a case of rheumatoid arthritis associated with Hashimoto's thyroiditis. The patient was a 40 year-old woman who had complained of polyarthralgia, joint-swelling and stiffness for seven years. She had a rheumatoid nodule and showed a positive RA test. Radiographic changes of hands and wrists showed osteoporosis, erosions and narrowing of joint space. Nonsteroidal anti-inflammatory drugs had been used for seven years. The diagnosis of Hashimoto's thyroiditis had been made by open biopsy of the thyroid gland seven years before. Serum T4, TSH, TBG, free T4, free T3 and r-T3 were all normal. On the other hand, serum T3 level was almost unmeasurable by radioimmunoassay. Binding of 125I-T3 to the patient's serum was studied by using polyethylene glycol (PEG) and column chromatography. By using the PEG method, the binding of 125I-T3 to the patient's serum was tenfold compared to control serum. Sephadex G-25 column chromatography (0.9 X 1.5 cm) of 125I-T3 with the patient's serum in the presence of 0.1% ANS showed an early radioactive peak, while control serum did not show an early peak. In the next experiments, the patient's serum was labelled with 125I-T3, mixed with human anti-IgG, IgM, IgA, lambda, kappa, incubated at 4 degrees C for 20 hours and centrifuged for 20 min. Strong binding to the anti-IgG and anti-lambda was detected. The presence of this abnormal T3-binding globulin in the patient's serum may have produced an undetectable T3 level.

Enhanced intestinal insulinotropic effect in streptozotocin-diabetic rats

To study the intestinal insulinotropic effects in the diabetic state, an investigation was made into the release of insulin from isolated rat pancreas perfused with portal venous effluent (PVE) obtained from the isolated perfused intestine of streptozotocin-induced diabetic rats. Rat intestine was perfused with Krebs-Ringer bicarbonate medium for 1 h, and the PVE was collected from both untreated and glucose-treated intestines of control and diabetic rats. The PVE, after adjusting its glucose concentration to the desired level, was used as the perfusing medium for the pancreas of a different rat. Glucose concentration in the perfusion medium was maintained at 5.5 mM for 20 min and at 16.7 mM for the next 30 min. Insulin output from pancreas perfused with PVE from untreated intestine of diabetic rats (252 +/- 45 ng/30 min, mean +/- SD) was similar to that of controls (269 +/- 72 ng/30 min). Pancreatic insulin output with PVE from glucose-treated intestine of diabetic rats (579 +/- 100 ng/30 min) was significantly greater compared with either that using PVE from untreated intestine of diabetic rats (P less than 0.01) or that from glucose-treated intestine of control rats (368 +/- 57 ng/30 min) (P less than 0.02). These results indicate that the insulinotropic effect is markedly enhanced in streptozotocin-induced diabetic rats.

Pathogenicity of newly isolated coxsackievirus B4 for mouse pancreas

Coxsackievirus B4 fresh isolates from patients with upper respiratory illness and aseptic meningitis were studied for their pathogenicity in the pancreas of SJL/J mice. Out of 12 virus isolates, 7 induced hypoglycaemia in mice 2 to 4 days after virus inoculation. All 3 isolates from faeces of patients induced hypoglycaemia in contrast to 3 viruses isolated from the cerebrospinal fluid which did not. Six isolates from throat swabs were either pathogenic (4 isolates) or non-pathogenic (2 isolates). It is concluded that at least two biologically distinct coxsackieviruses B4 prevail among humans.

A population survey of pancreatic islet cell antibodies and antithyroid antibodies

In a survey of one Japanese population, we detected pancreatic islet cell antibodies (ICA), antithyroid antibodies (ATA) and antinuclear antibodies (ANA). The prevalence of ICA was 6 out of 1125 cases, or 0.5%. ATA and ANA were detected in 8.9% and 1%, respectively. There were no cases of either type I or type II diabetes in subjects with ICA. But there was one case who had ATA and another with ANA. Serum samples from this population had been obtained once a year from 1979 and one case with neither ATA nor ANA was found positive for ICA in 1980. Identical tests for ICA were performed on 80 childhood diabetics as were carried out on type I diabetics. Pancreatic isles cell surface antibodies (ICsA), ATA and ANA were studied simultaneously. The prevalence of ICA in 80 cases was 36.3% and that of ICsA was 13.8%. 4 cases had both ICA and ICsA. The prevalence of ATA was 11.2% and that of ANA was 16.3%.

Effects of temperature shift on growth rate of Escherichia coli BB at lower glucose concentration

Although a shift in nutritinal conditins brings about transient unbalanced growth in normally grown Escherichia coli, a shift in temperature without changing the nutritional conditions results in immediate adaptation to the new conditions. However, when a medium contained an insufficient amount of nutrient, such as glucose, a temperature shift caused a lag time in temperature shiftup was primarily determined by the postshift temperature. These situatins were quite similar to those observed in nutrient shiftup, but a growth profile during the lag time was more distorted than that found in the nutrient shiftup. The transient unbalanced growth appeared to be caused by a difference in physiological states of bacteria, as expressed by macromolecule content per cell characterized by the pre and postshift environments, and was capable of expressing theoretically its profile and duration according to the model of Cooper and Helmstetter. On the other hand, the shiftdown in temperature in the presence of a limiting concentration of glucose caused extraordinarily long lag time, and transient cessation of cell division during that period. This response was unable to explain by the Cooper and Helmstetter model. In contrast to the temperature shiftup, the duration of lag time in the shiftdown was expresed as functions of the poshift temperature and the difference in physiological states of the pre- and postshift environments.

Antinuclear antibodies in childhood diabetics

Antinuclear antibodies (ANA) were detected both in type 1 diabetic children and in control subjects. The incidence of ANA in eighty of these diabetics was 16.3%, as determined using two different substrates, human pancreas and human peripheral leucocytes. The incidence and the patterns in the detection of ANA were the same. Four hundred and seventy-three children and one thousand one hundred and twenty-five adults served as the controls. The incidence of ANA in non-diabetic children was 0.8% and that in one adult population was 1.1%. Therefore, the incidence of ANA in childhood diabetics was significantly higher. We studied autoantibodies in childhood diabetics, in normal children and in one adult population. Pancreatic islet cell antibodies (ICA) were detected in 29 out of 80 type 1 diabetics (36.3%) in two out of 473 normal children (0.4%) and in six cases in one population (0.5%). thyroid microsomal antibodies (MCHA) were detected in 9 out of 80 childhood diabetics and the incidence of MCHA in type 1 diabetics was significantly higher than in the controls.

Novel aspect of cyclic 3',5'-adenosine monophosphate synthesis in Escherichia coli 3000A1

A kinetic analysis of cyclic 3',5'-adenosine monophosphate (cAMP) synthesis in an adenine auxotroph of Escherichia coli 3000 was made by assaying the incorporation of [3H]adenine into cAMP during exponential growth. The rate of increase in intracellular [3H]cAMP was very slow (0.1-0.2 pmol/min/DU660). The steady state level was attained at about 40-min incubation after the addition of [3H]adenine, and was estimated to be 5 to 7 pmol/DU660. The rate and level of intracellular cAMP were scarcely affected by growth conditions, such as change of carbon source, whereas the excretion of cAMP into the medium began immediately after the addition of [3H]adenine, and continued at a rate of 5 to 7 pmol/min/DU660 in the glycerol medium. The excretion rate decreased to 1.4 pmol/min/DU660 in the presence of glucose. These results are inconsistent with the view that the excretion rate is dependent on the intracellular concentration of cAMP. Although the decreased rate of cAMP synthesis in the presence of glucose accounts for the permanent catabolite repression of inducible enzyme systems, no immediate depression in cAMP synthesis, which might account for the transient repression, was found after the addition of glucose.

Effect of growth conditions on catabolite repression and cyclic AMP synthesis in Escherichia coli 3000A1

Catabolite repression of beta-galactosidase synthesis in E. coli 3000A1 (adenine-) was studied under a variety of growth conditions. The differential rate of induced beta-galactosidase synthesis was maximal at the growth rate of 0.75 division per h, irrespective of whether growth conditions were aerobic or anaerobic. The addition of cyclic AMP (cAMP) to the medium partly restored the repressed synthesis of beta-galactosidase under some growth conditions, but showed little or no effect on the enzyme synthesis under other conditions. Although growth rate and profile of beta-galactosidase synthesis in glucose-grown cells were similar to those in arabinose-grown cells, the acceleration of beta-galactosidase synthesis upon the addition of cAMP was found only in glucose-grown cells. The cells aerobically grown in the presence of glycerol, xylose, or arabinose showed a high synthetic rate of cAMP and were insensitive to exogenously supplied cAMP as regards beta-galactosidase synthesis. Although the cells grown with glucose showed similar rates of cAMP synthesis under aerobic and anaerobic conditions, the differential rate of beta-galactosidase synthesis was much higher in the anaerobic state than in the aerobic state. These findings support the idea that catabolite repression found in the strain is caused through two mechanisms, i.e., cAMP-mediated and cAMP-independent ones.

HLA-DR specifications in Japanese with juvenile-onset insulin-dependent diabetes mellitus

Specific allelic associations vary among ethnic groups. We studied the distribution of HLA-A,-B,-C, and -DR antigens in 34 Japanese juvenile-onset diabetic patients. The focus of our current work was HLS-DR antigens because there have been few studies of Japanese with this disease. A significant increase in the frequency of HLA-DR4 was found in patients but not in unaffected persons: DR4 was found in 56.3% of the patients versus 32.6% of the unaffected persons. However, the negative correlation between DR2 and patients was not statistically significant.

Islet-cell antibodies and HLA type in Japanese insulin-dependent diabetics

Pancreatic islet-cell antibodies (I.C.Ab.) were detected in the sera of 6 of 123 patients with insulin-dependent diabetes mellitus of recent onset, compared with only 2 positive results among the 434 control sera. The prevalence of humoral I.C.Ab. was strongly dependent on the duration of the diabetes, being 4 of 6 I.C.Ab. positive patients during the first year from diagnosis and falling to 2 of 6 I.C.Ab. positive patients at one to three years. Over four years from the time of diagnosis, there was no I.C.Ab. in the sera of the diabetics. Six I.C.Ab. positive in our group of 123 diabetic patients showed no association with any particular B locus antigen or DYT.

Distribution of coenzyme B12-dependent diol dehydratase and glycerol dehydratase in selected genera of Enterobacteriaceae and Propionibacteriaceae

The presence of diol dehydratase and glycerol dehydratase was shown in several bacteria of Enterobacteriaceae grown anaerobically on 1,2-propanediol and on glycerol, respectively. Diol dehydratases of Enterobacteriaceae were immunologically similar, but distinct from that of Propionibacterium freudenreichii.

Antimicrosomal antibodies, gastric parietal cell antibodies and antinuclear factors in insulin dependent diabetes mellitus

Thyroid antimicrosomal antibodies, gastric parietal cell antibodies (PCA) and antinuclear factors were studied in 208 insulin dependent diabetic (IDD) according to the duration of diabetes and patient's age at the time of testing. Antimicrosomal antibodies were found in 11 out of 47 (23.4%) IDD with the duration of less than one year, however this value declined to 13.1% at 1 to 3 years, 15.3% at 4 to 5 years, 10.8% at 6 to 10 years and 5.8% at more than 10 years. Of the 47 IDD, 7 (14.8%) were positive for gastric parietal cell antibodies. The prevalence of PCA declined with increasing duration of diabetes. However, this decrease in the prevalence of antimicrosomal antibodies and PCA was not so extreme as that of pancreatic islet cell antibodies. Antinuclear factors did not reveal a significant correlation with the duration of diabetes. In normal controls, the prevalence of antimicrosomal antibodies, PCA and the antinuclear factors increased progressively with age. In IDD, the prevalence of the antinuclear factors was also progressively greater with age. However, the prevalence of antimicrosomal antibodies in IDD decreased with age and those of PCA showed the lowest percent in the 40-69 year-age group.

Circulating immune complexes in the serum of diabetes mellitus in childhood by a modified 125I-C1q binding test

The 125I-C1q binding test for the detection of soluble immune complexes in native unheated human serum was applied to the study of sera from 52 patients with diabetes mellitus in childhood. This radiolabeled C1q binding test is more sensitive and reproducible among the various methods proposed for the detection of immune complexes. The 125I-C1q binding activity in 52 sera from diabetes mellitus in childhood was 9.47 +/- 0.36% compared to 6.94 +/- 0.74% in normal controls. 125I-C1q binding values in diabetes mellitus in childhood were significantly higher than normal controls. Slight high values were seen in 3 patients with positive anti-DNA-antibodies in diabetes mellitus in childhood. 125I-C1q binding was not significantly increased in patients with positive antithyroid antibodies and insulin antibodies. There was no significant correlation between the duration of diabetes and 125I-C1q binding activity.

Thyroglobulin and microsomal antibodies in patients with insulin dependent diabetes mellitus and their relatives

The sera for 88 parents and 9 siblings of 73 patients with insulin dependent diabetes mellitus in childhood and 437 controls matched in age and sex, were tested by the thyroglobulin and microsome-coated tanned red cell hemagglutination test (Fuji-Zoki Co. Tokyo). None of 73 children with diabetes mellitus had antithyroglobulin antibodies, whereas twelve (16.4%) had antimicrosomal antibodies compared with the incidence of 0.4% and 1.1%, respectively, in 437 controls. In the parents and siblings of these probands, thyroid antibodies were also found in increased incidence. The incidence of antimicrosomal antibodies in the 68 mothers was significantly higher than in controls matched for age and sex, but the incidence of the positive thyroid antibodies in the 20 fathers and 9 siblings was not significantly different from that in control populations. The incidence of thyroid antibodies tended to be higher, though not significant, in parents and siblings of diabetic children with positive thyroid antibodies than in those of diabetics with negative ones. These findings suggest that immunogenetic factors may be responsible for the pathogenesis of some cases of diabetes mellitus in childhood.

The leucocyte migration inhibition test and subpopulations of peripheral lymphocytes in insulin-dependent diabetics

The leucocyte migration inhibition test (LMT) was performed by the agarose plate method with thyroid and pancreatic antigens in patients with insulin-dependent or independent diabetes mellitus. The mean migration indices with thyroglobulin, thyroid mitochondria and beef insulin were not significantly different in insulin-dependent diabetics from those in insulin-independent diabetics or normal controls. However, significant inhibition of leucocyte migration was observed in insulin-dependent diabetics when thyroid microsome or pancreatic extract was used as antigen. Although no significant difference was found in the percentages of T and B lymphocytes between insulin-dependent diabetics and insulin-independent diabetics or normal controls, the results of LMT strongly suggest the presence of cellular immunity against the thyroid and pancreas in insulin-dependent juvenile-onset diabetes.

Coenzyme B12-dependent diol dehydratase: regulation of apoenzyme synthesis in Klebsiella pneumoniae (Aerobacter aerogenes) ATCC 8724

Immunochemical studies demonstrated that Klebsiella pneumoniae (Aerobacter aerogenes) ATCC 8724 produces only a single diol dehydratase whether grown on glycerol or on 1,2-propanediol. The enzyme was subject to induction by 1,2-diols and to catabolite repression reversed by cyclic AMP.

[Subpopulations of peripheral lymphocytes in insulin-dependent diabetics (author's transl)]

There is an increasing evidence that autoimmune mechanisms may have a role in the pathogenesis in insulin-dependent diabetics. The numerical and functional study of peripheral blood lymphocytes in diabetes mellitus might indirectly contribute to the understanding of its pathogenesis. In this study, detection of peripheral blood T lymphocytes was measured by rosettes with sheep red blood cells (SRBC), and B lymphocytes were measured by immunofluorescence with specific antiserum to immunoglobulins. The mean (+/- SD) percentage of SRBC was 67.6 +/- 7.2 in 21 normal subjects, 71.5 +/- 7.0 in 15 insulin-dependent diabetics, and 68.6 +/- 6.7 in 30 insulin-independent diabetics. There was no difference in the absolute T-lymphocyte number per mm3 in these three groups. Insulin-dependent diabetics showed a normal percentage and absolute number of B lymphocytes when compared with normal subjects.

Macromolecule synthesis of Escherichia coli BB at a lower or transient growth state

Macromolecule synthesis in Escherichia coli BB at lower growth rates was investigated. The results indicate that a deviation in ribonucleic acid (RNA) content per cell at a lower growth rate from the exponential relationship to a specific growth rate is entirely attributable to the presence of nonviable cells, in which the RNA content is lower than in viable cells. Based on this fact, a mathematical expression of macromolecule contents versus specific growth rate was devised. Moreover, continuous changes in macromolecule content during unbalanced growth from late-logarithmic phase to stationary phase were measured. Although growth rates changed continuously, the data on deoxyribonucleic acid (DNA) or RNA content versus the specific growth rate calculated from the increments in cell number satisfactorily fitted the exponential lines obtained under balanced growth at a higher growth rate. However, no such relationship was observed in the plot of DNA or RNA content versus the specific growth rate calculated from the increments in optical density.

Clinical significance of fucose level in glycoprotein fraction of serum in patients with malignant tumors

Serum fucose content in the glycoprotein fraction was determined in various patients with malignant and benign diseases. The results showed that, in contrast to benign diseases, malignant diseases were characterized by an increased fucose content in the glycoprotein fraction. However, no significant difference was noted in the fucose levels in the mucoprotein fraction. The increased fucose level in glycoprotein in malignant diseases was parallel to the increment in total fucose content in serum, which suggests that the increased levels in total fucose in malignant diseases, reported previously, are primarily due to the increase in fucose-containing glycoprotein.

[Leucocyte migration inhibition test in diabetes mellitus (author's transl)]

The leucocyte migration inhibition test (LMT) using the agarose plate method introduced by Clausen is simple and highly reproducible. Using thyroglobulin, mitochondria and thyroid microsomal fractions as antigens, LMT was performed on ten patients with insulin dependent diabetics, twenty patients with insulin independent diabetics, eleven patients with Graves' diseases, ten patients with chronic thyroiditis and ten healthy controls. The migration index was expressed as a percentage of migration and calculated from the following formula; (formula: see text). Using a thyroid microsomal fraction, the mean migration index for the insulin dependent diabetics (93.2 +/- 11.6) was significantly lower than in the normal subjects (104.3 +/- 10.9) (0.025 less than p less than 0.05). Using thyroglobulin as an antigen for the insulin dependent diabetics and insulin independent diabetics, the mean migration indices (+/-SD) were 93.7+/-10.8 and 102.8+/-10.6 respectively. The corresponding values for the control group were 100.6+/-7.3. Using a mitochondria, MI values for insulin dependent and independent diabetics were 97.7+/-5.5 and 99.6+/-12.6 respectively, while MI value for the control group was 103.9+/-13.6. The mean migration indices obtained with the mitochondria and thyroglobulin were not significantly depressed when the diabetic groups were compared with the normal subjects.

Macromolecule synthesis in Escherichia coli BB under various growth conditions

The kinetic behavior of the macromolecule synthesis of Escherichia coli during balanced growth in various media at different temperatures as investigated. The results indicate that macromolecule contents per cell can be expressed as exponential functions of the specific growth rate at a given temperature. It was shown that the content per cell at the zero growth rate was constant in each macromolecule component, irrespective of the growth temperature. The rate of ribonucleic acid (RNA) synthesis per unit weight of deoxyribonucleic acid and that of protein synthesis per unit weight of RNA were taken as efficiencies of RNA and protein synthesis, respectively; both of them were found to be dependent on the growth rate and temperature. The efficiency of RNA synthesis was found to be very high at a high growth rate, whereas that of protein synthesis was found to decrease above certain growth rate. At the same growth rate, an increase in the growth temperature resulted in a decrease in the efficiency of RNA synthesis but an increase in that of protein synthesis.

[Thyroglobulin and microsomal antibodies in diabetes mellitus in childhood (author's transl)]

The purpose of our study was to determine the incidence of thyroid antibodies in diabetes mellitus in childhood and to discuss the correlation between thyroid antibodies and insulin antibodies. The sera of 50 children with diabetes mellitus and 437 children as disease controls were tested by thyroglobulin and microsome-coated tanned red cell hemagglutination test (Fuji Zoki Co. Tokyo). One of the 50 children with diabetes mellitus (2%) was positive with antithyroglobulin antibodies and eleven (22%) were positive with antimicrosomal antibodies compared to 0.4% and 1.1% respectively in 437 disease controls. To clarify the association of insulin antibodies and thyroid antibodies in diabetes mellitus in childhood, insulin antibodies were demonstrated by using a modified method described by Wright. One of the 33 children with negative insulin antibody (2.8%) was positive with antithyroglobulin antibodies and eight (24%) were positive antimicrosomal antibodies. No evident correlation was observed between antithyroid antibodies and insulin antibodies.

An inhibitory effect of thymidine on its own conversion to nucleotide in Escherichia coli

The cellular levels of thymidine nucleotide pool in thymine-requiring mutants of Escherichia coli were followed. The pool levels of dTDP, dTTP and compound-X reached maximal values in much lower concentration of thymidine than those in thymine. In higher concentrations of thymidine, an inhibitory effect on its own conversion to nucleotide was observed. The inhibited step was suggested to be the conversion of dTMP to dTDP.

Effects of growth conditions on thymidine nucleotide pools in Escherichia coli

The cellular levels of thymidine nucleotide derived from [3H]thymine or [3H]thymidine were followed under various environmental conditions with a thymine-requiring mutant of Escherichia coli. It was shown that the pool sizes varied greatly with the growth conditions; that is, with growth temperature, inhibition of DNA synthesis of replacement of thymine with thymidine. In the strain used here, the level of compound X, presumably dTDP-sugar, was very much higher than those of other thymidine nucleotides. It is suggested that the conversion of thymine to thymidine is rate-limiting, while the conversions of thymidine to dTMP, and of dTMP to dTDP are more rapid than other steps in the salvage pathway of thymidine nucleotide.