Effects of one year of near-normoglycemia on peripheral nerve function in type 1 (insulin-dependent) diabetic patients

Ninety poorly controlled C-peptide negative type 1 (insulin-dependent) diabetic patients with chronic complications were allocated to intensified insulin treatment with either continuous subcutaneous insulin infusion or multiple insulin injections; 83 were studied over 1 year (seven patients dropped out of the study). Peripheral nerve function was assessed by clinical examination, malleolar vibration perception threshold, and motor and sensory nerve conduction velocities (MNCV; SNCV) in the median, ulnar, peroneal, and sural nerves. In order to assess the effect of metabolic control on peripheral nerve function, the results in patients with normal mean HbA1 levels during months 3-12 of the study less than 8.6% (tight control (tc); n = 50) were compared with those with abnormal mean HbA1 greater than or equal to 8.6% (poor control (pc); n = 33). Mean blood glucose was significantly higher in pc than in tc at months 2-9 and 11 (P less than 0.05). In pc median and ulnar SNCV were significantly lower at 6 and 12 months, and ulnar and peroneal MNCV at 12 months than in tc (P less than 0.05). No significant differences between the groups were observed for median MNCV, sural SNCV, and vibration sensation. Further analysis revealed that in well-controlled patients who showed abnormal peripheral nerve tests at baseline, median, and ulnar MNCV and SNCV but not peroneal MNCV, sural SNCV, and vibration sensation were significantly improved after 12 months as compared with poorly controlled patients with initially abnormal tests (P less than 0.05). There were no differences in nerve function between well- and poorly-controlled patients who had normal nerve tests at baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Somatic and autonomic nerve function during the first year after diagnosis of type 1 (insulin-dependent) diabetes

Somatic and autonomic nerve function was assessed by motor and sensory nerve conduction velocities (MNCV; SNCV), beat-to-beat variation at rest, speed of pupillary dilation, and pupillary latency time in 35 newly diagnosed type 1 diabetic patients aged 12-36 years. The nerve function tests were performed 18 +/- 2 (mean +/- SEM) days after the correction of initial ketosis and hyperglycaemia and again after 3 and 12 months of insulin therapy. Mean HbA1 levels of months 3 and 12 within the normal range less than 8.6% (mean: 7.2 +/- 0.2%) were observed in 24 patients (group 1) and greater than or equal to 8.6% (mean: 10.1 +/- 0.6%) in 11 patients (group 2). Group 1 showed no significant changes from baseline in the mean nerve conduction and autonomic functions after 3 and 12 months. In group 2 there was no change until three months, however, at 12 months there was a significant decrease in mean MNCV in the median, ulnar and peroneal nerves (p less than 0.05) and in mean SNCV in the median (p less than 0.05) and sural nerves (p less than 0.01), when compared to the baseline values. The autonomic function tests remained unchanged. No patient had symptoms of neuropathy during the period studied. These findings suggest that the deterioration of motor and sensory nerve conduction precedes that of cardiac and pupillary autonomic function in poorly controlled asymptomatic type 1 diabetic patients during the first year of the disease. Effective glycaemic control prevented progression of subclinical neuropathy, but did not reverse abnormalities which were present at diagnosis.

In vitro effects of anthraquinones on rat intestine and uterus

Isolated uterus and colon segments were taken from sennoside-pretreated female rats. They indicate a possible decrease in spontaneous contractility of both organ segments. Addition of rhein-Na, as one of the probable active metabolites of sennosides, into the bath medium of isolated colon and ileum segments of untreated rats showed a reduction in contractility at concentrations of more than 10(-5) and 10(-4) mol/l, respectively. Though rhein-Na in concentrations of more than 10(-4) mol/l impaired acetylcholine-mediated contractures of isolated colon, the antagonism was obviously partial and noncompetitive. Isolated uteri from previously estrogen-treated rats did not show a change in the contractile behaviour up to concentrations of 10(-4) mol/l rhein-Na, whereas higher concentrations induced an increase in contractions. The importance of this finding is not clear.

Peripheral and autonomic nerve function in long-term insulin-dependent diabetes

In a cross sectional study, motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV), beat-to-beat variation (BBV) at rest and speed of pupillary dilatation (SPD) have been investigated in 127 nonketonuric long-term insulin-dependent diabetics aged 19-72 yr and in age-matched control subjects. 84% of the patients had electrophysiologic abnormalities, 58% had symptomatic peripheral neuropathy, 35% had abnormal cardiac parasympathetic tests and 26% had abnormal pupillary tests. The most frequent pathologic feature was a decreased sural SNCV (66%). Among the patients without symptomatic peripheral neuropathy, 71% showed electrophysiologic abnormalities. MNCV and SNCV in median, peroneal and sural nerves correlated with BBV (p less than 0.005), but only peroneal MNCV was related to SPD (p less than 0.005). There was also a relationship between BBV and SPD (p less than 0.05). Glycosylated hemoglobin (HbA1) levels correlated inversely with median MNCV (p less than 0.001), and SNCV (p less than 0.03), peroneal MNCV (p less than 0.05) and sural SNCV (p less than 0.05). Patients with abnormal peripheral or autonomic nerve function tests or symptomatic peripheral neuropathy had significantly higher HbA1 levels than those with normal tests (p less than 0.04) or asymptomatic patients (p less than 0.01). Median MNCV and SNCV, sural SNCV and BBV deteriorated with age (p less than 0.05) and median SNCV and peroneal MNCV deteriorated with the duration of diabetes (p less than 0.001). Our findings show an association between peripheral and autonomic nerve dysfunction in long-term insulin-dependent diabetics.(ABSTRACT TRUNCATED AT 250 WORDS)

[H-NMR spectroscopy. Specificity of microbial sialidases against complex substrates]

The specificities of one viral and five bacterial sialidases were investigated by 1H-NMR-spectroscopy with substrates or substrate mixtures containing two sialic acid residues of different linkage types. This technique allows - in contrast to the methods used before - the simultaneous determination of the rates of hydrolysis of both NeuAc linkages in a single experiment. The substrate specificities of the enzymes are discussed on the basis of the relation of the rate constants k/k'. The data obtained are more exact and more informative than those of separate experiments as reported previously. Among the enzymes investigated, i.e. sialidases of fowl plague virus (FPV = VKH), Clostridium perfringens (CP), Vibrio cholerae (VC), Bifidobacterium bifidum var. pennsylvanicum (BBif), Bifidobacterium lactentis (BLac), and Arthrobacter ureafaciens (AU), the activity of the viral sialidase VKH shows the highest, the activities of the Bifidobacterium sialidases the lowest dependence on the nature and on the linkage type of the different substrates. All sialidases preferentially cleave the NeuAc alpha 2-3-Gal linkage with the exception of the enzyme of Arthrobacter ureafaciens (AU) which shows a higher affinity to alpha 2-6 linkages. However, this does not apply to the side-arm-linked NeuAc alpha 2-6 structure in NeuAc alpha 2-3 Gal beta 1-3 (NeuAc alpha 2-6)-GlcNAc beta 1-3Gal beta 1-4Glc (Substrate B). This substrate in generally cleaved very slowly and is hardly affected by the viral enzyme. After the alpha 2-3 linkage, the alpha 2-8 bond in NeuAc alpha 2-8 NeuAc alpha 2-3 Gal beta 1-4Glc(Substrate A) is most susceptible for the sialidases VKH, CP and VC. An elongation of the carbohydrate chain (Substrate D) is accompanied by a reduction of the rate of cleavage for all enzymes. The experiments with alpha 1-acid glycoprotein, fetuin, and with the glycopeptides obtained by proteolytic degradation of the latter, revealed the same specificity towards the alpha 2-3 and the alpha 2-6 linkages as the oligosaccharides. Influenced by the chemical nature and the size of the substrate, NeuAc is released from the native alpha 1-acid glycoprotein more quickly than from the corresponding glycopeptide. All sialidases investigated so far are strictly exo-enzymes as could be demonstrated by the cleavage of NeuAc alpha 2-8 NeuAc alpha 2-3 Gal beta 1-4Glc (Substrate A).

Success in strabismus therapy: a literature review

The purpose of this study was to review the literature pertaining to non-surgical cure rates for strabismus published since 1958 and compare it to Flom's prognostic model. However, no studies were found that could be compared directly to Flom's model. One reason for this was due to the use of different definitions of a cure by different clinicians. Another reason was the failure to categorize the data according to the effect that retinal correspondence, frequency, and direction of the deviation had on the cure rates. From the studies which specified Flom's functional cure or its equivalent, it was determined that strabismic cure rates could be broken down as follows: Constant esotropia-29%; Intermittent esotropia-73% Constant exotropia-53%; Intermittent exotropia-62% Suggestions were made for the reporting of data to make future research more comparable and useful to the practitioner.

Utility of skin testing in nutritional assessment: a critical review

To evaluate the claim that delayed cutaneous hypersensitivity skin testing is useful in nutritional assessment of hospitalized patients, we reviewed the English language literature of the last 12 years. Although several hundred publications discussed delayed cutaneous hypersensitivity testing and nutritional status, only 15 provided new, objective data correlating these variables in hospitalized adults. Of these, only three provided age-matched control groups to control for antigen variability, lack of prior exposure, and other technical problems. The majority of reports took no account of diseases (cancer, immune disease, infection) or therapies (radiation, drugs, surgery) known to affect skin test response. In the reports specifying different degrees of malnutrition, the most important group, those with less than obvious malnutrition, were not abnormal by skin testing. Ten reports described serial skin testing during nutritional intervention. Non reported serially tested controls without nutritional intervention, important since serial testing alone can augment skin test response. Nonnutritional intercurrent therapy which might affect skin tests was seldom mentioned. In the few reports specifying that nutritional repletion was even achieved, repleted patients were not separated from unrepleted in subsequent analyses. No report examined skin testing for its predictive accuracy, cost/benefit ratio, or influence on outcome. Because of these problems in experimental design, the frequent lack of appropriate controls, and the low specificity of abnormal delayed cutaneous hypersensitivity responses, we conclude that the utility of skin testing in nutritional assessment remains unproved.

[1H-NMR spectroscopy--a potent method for the determination of substrate specificity of sialidases (author's transl)]

We describe here the application of 1H-NMR spectroscopy to determine the substrate specificity of sialidases using a 1:1 mixture of NeuAc alpha 2-3Gal beta 1-4Glc and NeuAc alpha 2-6Gal beta 1-4Glc, one viral and five bacterial sialidases. This method utilizes the separate signals in NMR spectra, characteristic for the different alpha ketosidically linked NeuAc residues and also for bound and free NeuAc. The signals generally most suitable for these purposes are those of H3a, H3e and NCOCH3. By observation and integration of these signals we can follow--qualitatively and quantitatively--which and how many NeuAc residues of the substrates are hydrolized. In contrast to the generally used colorimetric tests it is now possible to investigate with this method substrates containing two or more NeuAc residues and to determine the corresponding rate constants for hydrolysis of the differently bound NeuAc molecules. The six sialidases used show large differences in their specificity as compared with our "model substrate": The sialidase from fowl plague virus hydrolizes NeuAc alpha 2-3Gal beta 1-4Glc nearly 18 times and the enzyme from Clostridium perfringens four times, from Vibrio cholerae two times faster than NeuAc alpha 2-6Gal beta 1-4Glc. On the contrary, the sialidase from Arthrobacter ureafaciens hydrolizes the alpha 2-6 linkage six times faster than the alpha 2-3 linkage. The sialidases from Bifidobacterium show no obvious differences in their specificities relative to the linkage.

[1H-NMR-spectroscopic evidence for the release of N-acetyl-alpha-D-neuraminic acid as the first product of neuraminidase action (author's transl)]

The 1H-NMR spectroscopy was used to study the anomeric configuration of N-acetyl-D-neuraminic acid released by the action of neuraminidase. The hydrolysis of NeuAcalpha 2 leads to 3 Gal-beta 1 leads to 4Glc (20mM) by the enzymes of Clostridium perfringens and Arthrobacter ureafaciens (50 mU, 150 mU and 800 mU, respectively) in 50mM Na/K-phosphate buffer pD 5.4 was observed by recording the spectra. On the basis of the characteristic signals of the protons at C-3 (alphaNeuAc: delta[H(3e)] = 2.72, delta[H(3a)] = 1.64; betaNeuAc: delta[H(3e)] = 2.25, delta[H(3a)] = 1.84) the product of the enzymatic cleavage was identified to be the N-acetylneuraminic acid in the alpha-anomeric form. Two hypotheses are discussed to explain how the enzymatic hydrolysis may occur and how N-acetyl-alpha-D-neuraminic acid leaves the catalytic site of the neuraminidases with retention of the C-2 configuration.

Effect of cannabinoids on estrous cycle, ovulation and reproductive capacity of female A/J mice

Virgin A/J female mice were intubated daily for 8 days (short term) or 70 days (long term) with 0, 1, 5, or 25 mg/kg delta 9-tetrahydrocannabinol (delta 9-THC) or 0, 3, 15, or 75 mg/kg crude marihuana extract (CME) in a sesame oil:polysorbate 80:saline vehicle. These dosages approximate light, moderate, and heavy human usage. Short-term exposure to CME has no significant effect on PMS-HCG-induced ovulation but appears to: (1) delay entry into proestrus at all dose levels; (2) depress serum progesterone during the luteal phase at the highest CME level used (75 mg/kg), and (3) inhibit female receptivity to males at least at the highest dosage. Long-term oral administration of CME or delta 9-thc had no significant effect on length of estrous cycles or mating (plug formation) but term pregnancies were reduced by 32 and 68% for medium and high dosages, respectively. After a 30-day recovery period, 80% of those females that failed to have successful pregnancies now became pregnant.

An analysis of transport, exchange, and binding of sodium and potassium in isolated amphibian follicles and denuded oocytes

The uptake and efflux of 22Na and 42K were studied in fully grown, prophase-arrested Rana pipiens follicles and denuded oocytes. Follicles and denuded oocytes contained large stores of both cations, although only 15–30% of the total Na+ and 1–2% of the total K+ pools exchanged within the 12-h period studied. 22Na uptake and efflux in follicles exhibited two-step kinetics with a smaller rapidly exchanging fraction (12–15%, t0-5 approximately 15 min), and a larger slow fraction (t0-5 approximately 0-5 day). Denuded oocytes displayed a single kinetic fraction with a rate constant similar to the slow fraction of follicles, suggesting that the fast fraction was associated with the follicular epithelium. Both follicles and denuded oocytes exhibited fast and slow 42K uptake kinetic fractions, although the follicular fast fraction was considerably larger. Conversely, whereas follicular 42K efflux also proceeded with two-step kinetics, 42K efflux from denuded oocytes appeared as a single slow fraction. Thus, a large portion of the fast K+ fraction taken up by the follicles is attributable to the somatic cells of the follicular envelopes. Na+ and K+ activities were measured in the cytoplasm of the in situ (follicular) oocyte using cation-selective microelectrodes. After correcting for Na+ and K+ associated with the follicular envelopes, only about 6% of the total ooplasmic Na+ and less than 1% of the K+ could be accounted for as bound or sequestered.

Selective isolation of Vibrio cholerae neuraminidase using an immobilized 4-(nitrophenyl)oxamic acid

N-(4-Nitrophenyl)oxamic acid[1] (1) was coupled with Sepharose 4B containing 1,6-diaminohexane as spacer group. This material was used as a specific adsorbent in the purification of Vibrio cholerae neuraminidase. The enzyme was completely retarded and separated from the bulk of the protein when washed with 50mM sodium acetate buffer, pH 5.0. A stepwise increase of sodium chloride concentration from 1.0 to 2.0M was found to be necessary for a sharp elution of neuraminidase activity. The purification was tenfold, and a recovery of more than 90% was obtained. Neuraminidase is only weakly retarded on a column of 1,6-diaminohexane coupled with Sepharose 4B and is not adsorbed by Sepharose 4B.

Inhibition studies on Vibrio cholerae neuraminidase

A series of viral neuraminidase inhibitors showing no structural analogy to neuraminic acids have been tested to find whether they are effective inhibitors of V. cholerae neuraminidase, too. Here we report the results obtained with the N-phenyloxamic acid derivatives 2 to 6 (R-NH-CO-COOR'; R = -C6H5NO2, -C6H5OH, -C6H5NH2; R' = -H, -C2H5; see Table 1) and with simple aromatic compounds structurally related to R, i.e. 4-nitroaniline (7), N-acetyl-4-nitroaniline (8), 4-nitrophenol (9), 2,4-dinitrophenol (10), and 4-aminophenol (11) (see Table 2). The inhibitory effects of 2 to 11 were studied according to the method of Dixon[19] in 0.1m sodium acetate buffer, pH 5.5, 2mM CaCl2, at 37 degrees C using the benzyl-alpha-ketoside of N-acetyl-D-neuraminic acid (1) as a substrate. The compounds 2 to 11 are shown to be competitive inhibitors of the enzymatic hydrolysis of the alpha-ketoside 1. The competitive inhibition kinetics are supported by the method of Lineweaver and Burk[20]. The inhibition constants (Ki) are found to be in the range of 0.03 to 5.7 mM. The simple aromatic compounds 7 to 11 show higher inhibitory activities than the phenyloxamic acid derivatives 2 to 6. In addition, significant differences in the Ki values were observed within the two series of inhibitors, whereby those containing a nitro group were most effective.

Control of chromosome behavior in amphibian oocytes. II. The effect of inhibitors of RNA and protein synthesis on the induction of chromosome condensation in transplanted brain nuclei by oocyte cytoplasm

We studied the effects of actinomycin D, alpha-amanitin, puromycin, and cycloheximide on the cytoplasmic activity of maturing Rana pipiens oocytes that induces chromosome condensation in transplanted brain nuclei. Treatment of oocytes with each inhibitor suppressed the chromosome condensation induced by metaphase oocytes to varying degrees depending upon the dose of inhibitor, despite the fact that untreated metaphase I oocytes already possessed chromosome condensation activity (CCA). Treatment of brain nuclei before injection completely suppressed condensation at all doses used. Chromosome condensation induced by metaphase II oocyte cytoplasm, however, was insensitive to all the inhibitors, even when the brain nuclei were pretreated. Oocytes treated with alpha-amanitin throughout maturation induced chromosome condensation when tested at metaphase II. Removal of the oocyte chromosomes after the germinal vesicle (GV) broke down did not prevent the development of CCA, whereas removal of the entire GV before initiation of maturation deprived oocytes of CCA. The results suggest that metaphase I oocyte cytoplasm stimulates synthesis of brain nuclear RNAs that are translated into proteins necessary for chromosome condensation, whereas metaphase II oocytes possess all the factors for chromosome condensation. In both cases, GV nucleoplasm appears indispensable for the development of CCA, whereas immediate activity of the oocyte genome is not required.

Simultaneous assay of neutral sugars and amino sugars by an automatic sugar analyzer: applications to glycoproteins

The simultaneous assay of neutral sugars and amino sugars commonly found in glycoproteins is described. The automatic sugar analyzer used for the determination is based on the ion-exchange chromatography of sugar-borate complexes on a strong anion-exchange resin. The sugars are identified with the orcinol/sulfuric acid reagent. While less than 40 nmol of mannose, fucose, galactose, glucose, xylose, or arabinose is sufficient for analysis at least 200 nmol mannosamine, glucosamine, or galactosamine is required; acidic monosaccharides cannot be determined. The technique of sugar analysis is applied to structural studies on natural compounds, e.g. the monosaccharide composition of lichenan and the carbohydrate moiety of the glycoproteins ovomucoid and Collocalia mucoid.