[The effects of insulin and glucose on the utilization of non-esterified fatty acid in the resting rat skeletal muscle]

The present study was undertaken to clarify the effects of insulin and glucose on the utilization of non-esterified fatty acid (NEFA) in the resting rat skeletal muscle using the perfusion technique. The 24hr-starved and non-starved rat hind limbs were perfused for one hour with the perfusion mediums containing 1mM palmitate and various concentrations of glucose and insulin, and sampling was performed to calculate the clearance of NEFA (F value). In the absence of glucose, the F value of the starved rat hind limb was less than that of the non-starved rats, independently of insulin concentrations (0 and 125 microU/ml) in the perfusion medium (p < 0.02). Moreover, there was no influence of insulin on the F value in both the starved and the non-starved groups. In the presence of 13.9mM glucose, there were no statistically significant differences in the F value without insulin between the non-starved and starved groups. However, the F value was increased in the presence of 62.5 or 125 microU/ml insulin, compared with that in the absence of insulin (p < 0.001), although when the insulin concentration was elevated to 500 microU/ml, it was decreased. Both in the non-starved and the starved groups independently of insulin concentrations, the F value in the glucose-added condition was increased, compared with that in the absence of glucose. These results indicated that the utilization of NEFA in the resting rat skeletal muscle was facilitated by the moderate supply of glucose, although it was suppressed by the presence of abundant glucose.

Changes in gnathosonic and tooth contact characteristics induced by experimental occlusal interferences created using a full-cast double crown

Occlusal sounds, contact timings and time moments were measured and analysed on 10 subjects onto whom an occlusal interference was created experimentally. A full-cast double crown was unilaterally set on the upper first molar of each subject, then gradually elevated for 0.06, 0.10, 0.20 and 0.30 mm by inserting a pre-calibrated metal folio. Occlusal sound was measured with an analyser designed for the purpose. Timings and time moments were analysed with a T-scan system. All measurements were performed at least 10 times per subject. The results showed that prolonged occlusal sound duration, changes in acoustic signal waveform and increased shift of the centre of effort were observed concomitantly with crown elevation. Differences in these values at 0.06 mm as compared with those at baseline were not statistically significant. This could be explained through a physiological compensation by the periodontal ligament. The differences with baseline were statistically significant from 0.10 mm ongoing. The distribution of occlusal conacts was determined by the use of a newly developed parameter. Referred to as 'Tap Score', the parameter consists of converting contact timings occurring in seven ranges into least-square-based weighted scores. Analysis of the tap score disclosed evident imbalance between the crowned and the non-crowned side starting from 0.10 mm elevation, whereby a forward shift of the major contact point was observed on the non-crowned side. Our study demonstrated that evident changes in gnathosonic and T-scan parameters are likely to occur at a crown elevation within a 0.06-0.10 mm range.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular carboxyl esterase activity is a determinant of cellular sensitivity to the antineoplastic agent KW-2189 in cell lines resistant to cisplatin and CPT-11

KW-2189, a novel antitumor antibiotic belonging to the duocarmycins, possesses marked DNA-binding activity upon activation by carboxyl esterase to its active form, DU-86. Three duocarmycins, KW-2189, DU-86 and duocarmycin SA, were active against the cisplatin (CDDP)-resistant human non-small cell lung cancer cell lines PC-9/CDDP and PC-14/CDDP, and the multidrug-resistant human small cell lung cancer cell line H69/VP. However, HAC2/0.1, a CDDP-resistant human ovarian cancer cell line which is also resistant to CPT-11 because of decreased intracellular activation of CPT-11, was about 12.8-fold more resistant to KW-2189. HAC2/0.1 was not resistant to other duocarmycins as compared to its parental cell line, HAC2. There was no difference between HAC2 and HAC2/0.1 with regard to the intracellular accumulation of KW-2189. Addition of 130 mU/ml of carboxyl esterase to the culture medium did not influence the sensitivity of HAC2 cells to KW-2189. However, the sensitivity of HAC2/0.1 cells to KW-2189 was enhanced to the level of HAC2. These results suggest that HAC2/0.1 is less potent than HAC2 in activating KW-2189. The carboxyl esterase activity of whole-cell and microsomal extracts from HAC2/0.1 was approximately 60% of that from HAC2. The cell-free experiment revealed that KW-2189 bound to DNA more efficiently in the presence of HAC2 than HAC2/0.1 cell extract. It was concluded that decreased intracellular carboxyl esterase activity in HAC2/0.1 cells caused decreased intracellular conversion of KW-2189 to its active form, thus producing resistance to KW-2189. The decreased conversion of CPT-11 to SN-38 in HAC2/0.1 cells might be explained by decreased carboxyl esterase activity.

Functional and evolutionary implications of a [3Fe-4S] cluster of the dicluster-type ferredoxin from the thermoacidophilic archaeon, Sulfolobus sp. strain 7

The dicluster-type ferredoxin is a key electron carrier in the cytoplasm of the aerobic and thermoacidophilic archaeon, Sulfolobus sp. strain 7, and contains 1 aspartate and 7 cysteine residues as possible ligands to two FeS clusters. The optical, electron paramagnetic resonance (EPR), and cyclic voltammetric studies suggest the presence of one each of [3Fe-4S]1+,0 (-280 mV) and [4Fe-4S]2+,1+ (-530 mV) clusters in the purified Sulfolobus ferredoxin, and the lower potential [4Fe-4S] center was scarcely reducible by excess dithionite even at pH 9. While the Sulfolobus ferredoxin has been known to function as an electron acceptor of 2-oxoacid:ferredoxin oxidoreductase (Kerscher, L., Nowitzki, S., and Oesterhelt, D. (1982) Eur. J. Biochem. 128, 223-230), it is not known whether one or both of two clusters is reduced during the steady-state turnover of the enzyme. Here we show by combinations of the optical and EPR spectroscopies that only the higher potential [3Fe-4S] cluster is reduced at the physiological pH during the steady-state turnover of the purified 2-oxoacid:ferredoxin oxidoreductase at 50 degrees C. The functional significance and evolutionary implications of the [3Fe-4S] center in dicluster-type ferredoxins are discussed.

Effect of arotinolol on insulin sensitivity in obese hypertensive patients

Insulin sensitivity in terms of glucose disposal rate was determined by using the hyperinsulinemic euglycemic clamp technique in seven obese hypertensive patients and nine normotensive control subjects. The technique was used on all study subjects at baseline and on the hypertensive patients after 12 weeks of arotinolol treatment. Mean supine systolic blood pressure decreased from 155 +/- 3 mm Hg before treatment to 133 +/- 6 mm Hg after treatment (P < 0.02), and diastolic blood pressure decreased from 100 +/- 3 mm Hg before treatment to 86 +/- 3 mm Hg after treatment (P < 0.05). The mean dose of arotinolol was 10 mg/d, except for one patient who received 20 mg/d. The glucose disposal rate during the last 30 minutes of the glucose clamp procedure was not significantly affected by treatment with arotinolol. Compared with the hypertensive patients, the glucose disposal rate in the normotensive subjects was significantly increased, both before and after treatment (P < 0.01). The study results show that the obese hypertensive patients were insulin resistant and that treatment with arotinolol did not significantly affect insulin sensitivity.

[Relationship between behavioral problems and cognitive status in Alzheimer type and mixed Alzheimer and vascular dementia]

To investigate the relationship between troublesome behavior and cognitive status in Alzheimer type dementia (DAT), and to know whether the addition of cerebrovascular ischemia modifies that relationship, we studied behavioral and cognitive data from a clinical series of 57 DAT patients (mean age: 83.4 yrs) and 31 patients with mixed Alzheimer and vascular dementia (MIX) (mean age: 83.4 yrs). All subjects were ambulatory and were recruited from among patients having been admitted to our affiliated nursing home. None of them had any serious systemic diseases. The Dementia Behavior Disturbance scale (DBD), originally developed by Baumgarten et al, and the Mini-Mental State (MMS) were used for the evaluation of behavioral problems and cognitive status, respectively. In the DAT group, a significant correlation was recognized between DBD and MMS scores. In the MIX group, however, DBD scores did not correlate with MMS scores. Among patients having MMS scores greater or equal to 20, those with MIX had higher DBD scores (mean 19.3) than those with DAT (mean 13.7), although MMS scores in these two subgroups were comparable. These findings suggest that in DAT, behavioral problems increase in conjunction with cognitive impairments. However, with the addition of cerebrovascular ischemia to Alzheimer pathology, behavioral impairments may progress independently of cognitive decline, with more frequent presentation of troublesome behaviors in the early stage of dementia.

A young case with multi-infarct dementia associated with lupus anticoagulant

A 39-year-old man was admitted because of an abrupt onset of right-side weakness and dysarthria. During the 2 years before admission, he had suffered from insomnia, depressed mood and progressive memory disturbance. Neurological and psychiatric examination revealed severe intellectual impairment in addition to the neurological deficits. Neuroradiological examinations revealed multiple brain infarcts. He had no risk factor for stroke except for lupus anticoagulant. He was diagnosed as having multi-infarct dementia associated with antiphospholipid antibodies. This case suggests that it is necessary to investigate antiphospholipid antibodies in addition to neuroradiological examination when relatively young patients present with unexplained cognitive or behavioral symptoms.

Effect of insulin on sodium reabsorption in hypertensive patients

The effect of insulin on sodium reabsorption was studied with the hyperinsulinemic euglycemic clamp technique, using lithium clearance as a marker of sodium reabsorption in the proximal tubule. The subjects were 12 nondiabetic hypertensive patients who were divided into two groups. In the first group, the effect of insulin on sodium and lithium reabsorption was examined. The second group served as a control. Blood glucose was continuously monitored from 9 AM to 10 AM (baseline period). Hyperinsulinemic euglycemic clamp was performed with an artificial endocrine pancreas by infusing insulin at a rate of 2 mU/kg.min from 10 AM to noon. In the control group the protocol was exactly the same except that glucose clamp was not performed. Urine was collected hourly from 9 AM to noon. In the glucose clamp group, urinary sodium excretion (UNaV) decreased by 42% during the second hour of the glucose clamp (P < .02). Clearance of lithium (CLi) and fractional distal sodium reabsorption [(CLi-CNa)/CLi] increased, and CNa/CLi decreased significantly during the glucose clamp. In the control group, UNaV and (CLi-CNa)/CLi remained unchanged, and CLi decreased significantly. As shown by the increase of CLi and (CLi-CNa/CLi, and the decrease of UNaV and CNa/CLi in the glucose clamp group, insulin decreases urinary sodium excretion by increasing distal sodium reabsorption, whereas it inhibits sodium reabsorption in the proximal tubule.

Comparison of effects of nicardipine and trichlormethiazide on insulin sensitivity in hypertensive patients

We performed a randomized, crossover study comparing the effects of nicardipine and trichlormethiazide on insulin sensitivity in 8 untreated essential hypertensive patients. They were treated either with nicardipine or trichlormethiazide for 12 weeks, after which they were treated with the alternative drug for a further 12 weeks. Insulin sensitivity was determined by the hyperinsulinemic euglycemic clamp technique. Nicardipine had no adverse effect on insulin sensitivity. Trichlormethiazide decreased insulin sensitivity index by 12%. As nicardipine does not have an adverse effect on insulin sensitivity, it should be preferred in patients who have a proven metabolic abnormality.

Insulin sensitivity test using a somatostatin analogue, octreotide (Sandostatin)

To assess the validity of the steady-state plasma glucose (SSPG) method using octreotide (Sandostatin), we compared the SSPG method with the euglycemic hyperinsulinemic clamp technique in ten non-obese, insulin-dependent diabetic patients. The SSPG method was performed by intravenous infusion of octreotide (0.5 microgram/min), insulin (2 mU/kg/min) and glucose (9 mg/kg/min) for 180 min. Octreotide suppressed endogenous growth hormone, glucagon and insulin secretion. A steady state condition was reached by 90 min, and the mean value of SSPG at 150 and 180 min was used as the index of insulin sensitivity. The euglycemic hyperinsulinemic clamp technique was performed with an artificial endocrine pancreas (Biostator), and insulin sensitivity was expressed as the glucose disposal rate (GDR) from 150-180 min. There was a significant correlation (r = 0.91, p < 0.001) between the results of the two methods. In conclusion, measurement of SSPG, using octreotide to suppress endogenous insulin secretion, is a reliable method to assess insulin sensitivity in man.

A novel antitumor antibiotic, KW-2189 is activated by carboxyl esterase and induces DNA strand breaks in human small cell lung cancer cells

KW-2189 has been selected as a lead compound for clinical trial among duocarmycin derivatives with structural similarity to CC-1065, a cyclopropylpyrroloindole. The purpose of this study was to examine the DNA-binding potency and the mechanisms of cytotoxicity of KW-2189. In order to analyze DNA-binding activity of KW-2189, plasmid pBR322 was treated with KW-2189 with or without pretreatment with carboxyl esterase, which we demonstrated to be an activating enzyme, and the products were examined by agarose gel electrophoresis and restriction enzyme analysis. Cytotoxic activity was examined by exposing a human small cell lung cancer cell line, NCI-H69 to KW-2189 with or without carboxyl esterase. Alkaline elution was performed to examine whether KW-2189 induces DNA strand breaks. DNA treated with KW-2189 and carboxyl esterase migrated faster than KW-2189-treated DNA, which migrated at the same rate as untreated DNA. In addition DNA treated with esterase-activated KW-2189 was protected from digestion by some restriction enzymes. KW-2189 showed concentration- and time-dependent growth inhibitory effect with IC50 values (drug concentration required for 50% growth inhibition) of 58 nM (96 h) to 1900 nM (1 h) in H69 cells. The IC50 values of 4-h exposure of H69 to KW-2189 with 0, 26, 130, 650 mU/ml carboxyl esterase were 460, 120, 30, and 7 nM, respectively. Time-dependent enhancement of cytotoxicity by carboxyl esterase was also observed. KW-2189 induced DNA strand breaks in H69 cells in a concentration-dependent manner around the IC50 value. We conclude that 1) KW-2189 is activated by carboxyl esterase to its active form(s), 2) activated KW-2189 has a stronger DNA-binding activity and cytotoxicity than KW-2189, 3) DNA cleavage is one of the major mechanisms of KW-2189-mediated cytotoxicity.

Effects of NG-monomethyl-L-arginine, indomethacin, and aspirin on the vasodepressor response to low doses of endothelin-1 and endothelin-3 in rats

Low doses (< or = 100 pmol/kg) of endothelin-1 (ET-1) and endothelin-3 (ET-3) elicited a fall in mean arterial pressure (MAP) and a dose-related reduction in hindquarter vascular resistance in anesthetized rats. The depressor response to low doses of ET-1 or ET-3 was short-lived (about 10 sec) and reversible. High doses (> or = 200 pmol/kg) of ET-1 and ET-3 elicited a biphasic response; an initial fall in MAP followed by a gradual increase in MAP. The pressor response to large doses of ET-3 was less than that to large doses of ET-1. On the other hand, the depressor response to low doses of ET-3 was similar to that to low doses of ET-1. Both ET-1 and ET-3 at low doses exhibited primarily a vasodilatory activity. Pretreatment with NG-monomethyl-L-arginine (L-NMMA), a compound that inhibits nitric oxide (NO) production by endothelial cells, attenuated the hypotensive and hindquarter vasodilating effects of low doses of these isopeptides, indicating that the hindquarter vasodilating responses to these peptides depend upon the release of NO from endothelial cells. On the other hand, pretreatment with either aspirin or indomethacin did not alter the hypotensive or the hindquarter vasodilating effects of either ET-1 or ET-3, indicating that cyclooxygenase products may not be involved in the vasodepressive mechanisms of these peptides. L-NMMA attenuated the vasodilating effects of these peptides, but did not completely inhibit the response, suggesting that NO production by endothelial cells plays only a partial role in the vasodilation of ET in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of altered Q-T interval and sympathetic nervous system dysfunction in diabetic autonomic neuropathy

We examined the relationship between the Q-T interval and autonomic dysfunction in 74 diabetic patients and age-matched controls. The expected Q-T interval was standardized as a function of the R-R interval in 646 healthy controls, and the delta Q-T defined as the difference from the expected value. Propranolol increased delta Q-T, confirming this as a parameter of autonomic function. No relationship between delta Q-T and duration of disease, glucose control, retinopathy or proteinuria was observed. However, significant correlations were found between the delta Q-T and delay of nerve conduction velocity, orthostatic hypotension, altered Valsalva ratio, abnormal Valsalva overshoot, cold pressor response, decreased norepinephrine concentration and sympathetic function score in diabetic patients.

Type 1 (insulin-dependent) diabetic patient with remarkable infiltration of lymphocytes to the islets

We report the case of a 62-year-old woman who was admitted to our hospital with diabetic ketoacidosis. Her urinary C-peptide was 3.5 micrograms/day, HLA typing was DR9, and serum was positive for islet cell antibodies. There was no significant increase in the major viral titer. Pancreatic head tumor was suspected, and pancreaticoduodenectomy was performed. The pathology of this tumor was polycystic adenoma. We examined the surgical specimen from around the tumor histologically. The pancreatic islets had decreased in number. The immunohistochemical staining of islets for insulin, glucagon and somatostatin showed that the number of B cells had decreased remarkably, while A and D cells were preserved. Marked lymphocytic infiltration was observed in the islets. The majority of lymphocytes were helper/inducer and suppressor/cytotoxic T cells, which did not express HLA-DR antigen or interleukin-2 receptor. No NK cells were present in the islets. The present case, which was examined histologically in detail, is consistent with the previously proposed hypothesis that autoimmunity might play an important role in the pathogenesis of insulin-dependent diabetes mellitus.

Physiology and morphology of spiking local interneurons in the terminal abdominal ganglion of the crayfish

Not only nonspiking local interneurons but also spiking local interneurons in the terminal abdominal ganglion of the crayfish (Procambarus clarkii Girard) contribute to form the motor output of the uropod. In this study, 14 spiking local interneurons are identified by their gross morphology and physiological properties including the sensory inputs from the uropod and premotor output onto the uropod motor neurons on both sides. Morphologically, they are divided into three groups based on the position of their somata: anterior, medial, and posterior. The main branches of interneurons in each group are usually extended on the side contralateral to the soma, or they have profuse bilateral branches. Physiologically, all of them receive excitatory inputs from the afferents innervating the exopodite on the side ipsilateral their main branches. They are usually silent, and spike only in response to sensory stimulation. The majority of them (11 out of 14 neurons) have output effects on the uropod motor neurons that elicit reciprocally closing pattern. They increased the activity of the closer motor neurons and decreased the activity of the opener motor neurons. Only one interneuron inhibits the closer motor neurons. The remaining two interneurons coactivate both the antagonistic motor neurons. Since the reciprocal closing pattern of the uropod motor neurons is elicited in response to sensory stimulation of the uropod, spiking local interneurons may initiate this local reflex circuit. They detect the initiation of the stimulus and convey signals from the sensory to the motor side.

Specific modification of structure and property of myoglobin by the formation of tetrazolylhistidine 64(E7). Reaction of the modified myoglobin with molecular oxygen

Tetrazole-myoglobin (Tet-Mb), a site selectively modified myoglobin with tetrazole anion (-CN4-) covalently attached to the imidazole N epsilon of the distal histidine 64(E7) (see Fig. 1; Kamiya, N., Shiro, Y., Iwata, T., Iizuka, T., and Iwasaki, H. (1991) J. Am. Chem. Soc. 113, 1826-1829), exhibited unique properties in the reduction from ferric to ferrous states and in the reaction of its deoxy form with O2. The redox potential of Tet-Mb is obtained to be -193 mV, which is much lower than that of unmodified (native) myoglobin (50 mV), possibly due to the electrostatic interaction between the heme iron and the tetrazole group. The ferrous deoxy form of Tet-Mb was rapidly oxidized to its ferric form in the reaction with O2 at room temperature through an intermediary formation of its oxy form and with the generation of O2-. The oxy form of Tet-Mb can be detected by the optical spectral measurement at -12 degrees C, the rapid scan measurement at room temperature, and the electron spin resonance measurement of its cobalt-substituted derivative (Tet-Mb(Co2+)) at 77 K. In the kinetic measurement of the O2 binding reaction to Tet-Mb, its association and dissociation rate constants in the bimolecular reaction were 6.1 x 10(7) M-1 s-1 and 2200 s-1, respectively, showing that the tetrazole modification of His-64 extremely accelerates its association and dissociation rates. Taken together with the extremely fast autoxidation rate (53 h-1) obtained, these kinetic results suggested that the channel of O2 from the solvent region to the protein interior is open enough to pass the external ligand. The structure is discussed in relation to those of some genetic mutants. Taking these properties, we demonstrated that Tet-Mb can catalyze O2 consumption to generate O2-, coupled with the NADH-supported enzymatic reduction system of cytochrome P-450cam under an aerobic condition.

Doxazosin improves insulin sensitivity in hypertensive patients

Insulin sensitivity in terms of glucose disposal rate was measured by the hyperinsulinemic/euglycemic clamp technique in 10 hypertensive patients and 7 normotensive control subjects before and after 12 weeks of doxazosin therapy. Supine blood pressure fell significantly, from 150/98 mmHg before treatment to 136/90 mmHg after treatment (systolic P < 0.001/diastolic P < 0.01). The average dose of doxazosin at the end of the study was 3.3 +/- 0.4 mg/day. The glucose disposal rate during the last 30 minutes of the glucose clamp procedure was significantly increased, from 5.8 +/- 0.7 mg/kg/min before to 7.8 +/- 0.7 mg/kg/min after treatment (P < 0.02). Insulin sensitivity was 8.7 +/- 0.4 mg/kg/min in the normotensive subjects, which represented a significant difference when compared with that of the hypertensive subjects before treatment (P < 0.01). Steady-state serum insulin concentrations, as measured during the glucose clamp procedure, were 172 +/- 10.4 microU/ml before and 176 +/- 13.5 microU/ml after doxazosin treatment; these levels were significantly higher than the 137 +/- 7.0 microU/ml reading obtained in the normotensive subjects (P < 0.05). Study results show that hypertensive patients tend to be insulin resistant and that treatment with doxazosin improves insulin sensitivity.

Intersegmental ascending interneurons controlling uropod movements of the crayfish Procambarus clarkii

The premotor effects of intersegmental ascending interneurons upon uropod motor neurones in the crayfish Procambarus clarkii (Girard) are examined with intracellular recording and staining techniques. We show that many ascending interneurones can affect the activity of the antagonistic opener and closer motor neurones in the terminal ganglion. Based upon soma position, ascending interneurones are divided into three groups of rostral, medial, and caudal interneurones. Twenty-four ascending interneurones are characterized physiologically according to their inputs from the tailfan and their output effects on the uropod motor neurones of both sides. Each interneurone is identifiable as a unique individual by means of overall shape, soma position, number of main branches, the commissure in which primary neurites cross the midline, axon position in the 5th-6th abdominal connective and physiological responses. They are classified into six classes; coactivating, coinhibiting, reciprocally closing, reciprocally opening, variably effective, and not effective interneurones, according to their premotor effects on the uropod motor neurones. These ascending interneurones seem to act as multifunctional units conveying sensory information from the tailfan to the anterior abdominal ganglia and, at the same time, influencing the uropod motor pattern in the terminal abdominal ganglion.

[Double meningoencephalitis with herpes simplex virus and rubella virus]

A 47-year-old man suffered from a headache, fever and memory disturbance. He was admitted to Morimoto Hospital. Neurological examination revealed disturbance of memory of recent events. Cranial nerves were normal. Muscle strength of the extremities was normal, except for Barré's sign of the right upper extremity. Deep tendon reflexes were exaggerated bilaterally, and extensor plantar response of the left side was elicited. Sensory examination showed no abnormality. Cerebellar sign was not recognized. Meningeal sign was slightly but clearly showed. CT scan demonstrated brain swelling at the right insular cortex region followed by severe hydrocephalus with dilatation of the lateral and the third ventricles. Cerebrospinal fluid showed high CSF pressure (250 mmH2O), pleocytosis (C.C. 359/mm3) and elevated protein level (213 mg/dl). Virological examination revealed herpes simplex virus (HSV) (CF) 32x, HSV-1 IgG (EIA) 4,050X, rubella virus IgE (EIA) 6,060X, cytomegalovirus (CMV) IgG (EIA) 1,130X in serum and HSV (CF) 1X, HSV-1 IGg (EIA) 1,430X, rubella virus IgG (EIA) 1,480X, CMV IgG (EIA) 587X in CSF. The ratio of serum/CSF of HSV and rubella virus titers by EIA methods were 2.83 and 4.10, respectively. He was treated by acyclovir 1,000 mg/day and gamma globulin, but his condition get worse acutely and died at 15th hospital days. This case was considered as a meningoencephalitis caused by simultaneous HSV and rubella virus infection.

Characterization of superoxide dismutase-insensitive cytochrome c reductase activity in HL-60 cytosol as NADPH-cytochrome P450 reductase

A flavoprotein dehydrogenase assayed for the activity of electron transfer from NADPH to cytochrome c was highly purified from the cytosolic fraction of differentiated human promyelocytic leukemia HL-60 cells. The purified enzyme had an apparent molecular mass of 68 kDa by sodium dodecyl sulfate gel electrophoresis and an equimolar amounts of flavin mononucleotide and flavin-adenine dinucleotide. The purification factor of the enzyme with respect to the cytosolic fraction was close to 1100 and the recovery of activity was approximately 18%. Reduction of cytochrome c by NADPH indicated Michaelis-Menten kinetics with a Km value of 1.50 microM for NADPH. When cytochrome c was the varied substrate, a Km value of 4.10 microM was obtained. NADH was not an effective electron donor for cytochrome c reduction and NADPH-dependent reduction of nitroblue tetrazolium was negligibly small. The purified enzyme alone did not exhibit superoxide production, and NADPH oxidase activity was not markedly stimulated upon incubation of the reductase with cytochrome b558 purified from porcine neutrophils. The purified flavoprotein gave a positive cross-reactivity to polyclonal antibodies raised to microsomal NADPH-cytochrome P450 reductase, indicating structural homology between these enzymes. The catalytic properties of the purified NADPH-cytochrome c reductase have similarities to those of liver NADPH-cytochrome P450 reductase.

Social and economic impact on youth-onset diabetes in Japan

OBJECTIVE

To investigate the social and economic backgrounds of youth-onset insulin-treated diabetes mellitus in Japan.

RESEARCH DESIGN AND METHODS

We conducted a case-control study on 35 diabetic patients with age at onset of 19.5 +/- 5.1 yr and duration of diabetes 14.9 +/- 6.7 yr. Sex- and age-matched (within 5 yr) siblings were selected as control subjects. Thirty-five matched pairs were asked to complete a questionnaire, including employment status and educational achievement.

RESULTS

Overall, diabetic patients were more likely to encounter job refusal in their lives than sibling control subjects (20 vs. 0%), and most patients (6/7) who had an experience of job refusal told job interviewers about their diabetes. Although the full-time employment rate and unemployment rate did not differ significantly between patients and control subjects, income levels were lower among patients than in the sibling (1600 vs. 2500 thousand yen). A multivariate analysis indicated that patients had lower incomes than control subjects after adjusting for the effect of physical disability. Educational achievements in the patients were similar to those in the siblings.

CONCLUSIONS

These results suggested that diabetic patients had several social and economic problems in Japan. Further studies in more subjects are required to grasp the social and economic impact on diabetes precisely, and minimize the social handicaps on diabetic patients.