Decreased circulating CD34+ cells are associated with progression of diabetic nephropathy.

AIMS: Circulating progenitor cells such as CD34+ cells play a key role in maintenance of vascular endothelial function and neovascularization, and a decrease in the number of CD34+ cells is associated with cardiovascular disease. However, the contribution of circulating progenitor cells to microvascular disease, such as diabetic nephropathy, is unclear. This study was therefore designed to clarify the association between diabetic nephropathy and circulating CD34+ cells. METHODS: We measured circulating CD34+ cell numbers in 85 Type 2 diabetic patients aged 40-70 years with normo- and microalbuminuria and determined the association with urinary albumin excretion rate (UAER). RESULTS: The number of circulating CD34+ cells significantly correlated with log UAER (r = -0.289, P = 0.008). Furthermore, in patients with low numbers of CD34+ cells (0.68 > cells/microl, lowest quartile of CD34+ cell number) UAER increased significantly after 12 months compared with baseline [from 34.3 +/- 7.0 to 53.6 +/- 10.8 mg/g creatinine (gCr), P < 0.05], whereas in patients with a high number of CD34+ cells (1.0 < cells/microl, highest quartile of CD34+ cell number) UAER did not change (from 16.7 +/- 4.8 to 20.1 +/- 3.0 mg/gCr). CONCLUSIONS: These results suggest that a decreased number of circulating CD34+ cells is involved in the progression of diabetic nephropathy and may be a predictor of the disease.

Febrile convulsions in northern Japan: a quantitative and qualitative analysis of EEG and clinical findings.

In an attempt to describe the characteristics of febrile convulsions (FC) 133 children with a history of FC were checked neurologically at health centers in northern Japan. Using categorical data from principal component analysis, family history of FC, recurrence and body temperature prior to convulsion, EEG disorders, exogenous factors, age at onset as the principal components were extracted. A quantitative and qualitative analysis of EEG showed that children with FC had more paroxysmal and basic abnormalities, that the rate of appearance of theta wave was more common and of alpha wave was less common, and that mean values of frequency ranges of theta and alpha wave ranges together were significantly lower in the background activity than those of control group children.

Effects of high-frequency sound on the guinea pig cochlea. Electrophysiological study using cochlear microphonics, action and endocochlear potential.

There are only a few studies investigating the effect of high-frequency sound on hearing. Authors investigated experimentally the effect of long exposure to high-frequency sound (19 and 25 kHz) below 100 dB (SPL) on guinea pig inner ear. Changes in cochlear microphonics (decrease of maximum output voltage) and especially in endocochlear potential (decrease of the absolute value of negative potential) were observed. The effects of high-frequency sound (10-30 kHz) on the inner ear were discussed.

The effect of 6 kHz tone exposure on inner ear function of the guinea pig: relation to changes in cochlear microphonics, action potential, endocochlear potential and chemical potentials of K(+)-ions and Na(+)-ions, using a double-barrel glass electrode.

Using 97 male albino guinea pigs and applying electrophysiological methods, the effects of a 6 kHz tone were investigated at a moderate sound pressure level to the inner ear during a 24-h exposure time. Following exposure to the 6 kHz tone at 90 dB, cochleas showed decreased maximum output voltage of cochlear microphonics (CM) and action potential (AP). In the endolymph, K+ ion and Na+ ion concentrations remained unchanged during 40 min anoxia and 90 dB tone exposure. At 80 dB sound exposure decreases in maximum output voltage of CM and AP and decreases in the absolute value of EP could not be detected. Endolymph K(+)-ion Na(+)-ion concentrations were also unchanged. These findings indicate that diffusion potentials are induced at the same time as decreases of maximum output voltage in CM induced by exposure to sound at 90 dB.

Effects of 250 and 500 Hz tone exposure on the inner ear of guinea pigs as determined by electrophysiological techniques.

The electrophysiological study of cochlear microphonics (CM), whole nerve action potential (AP) and endocochlear potential (EP) were examined. (1) With the extension of the exposure time of 500 Hz tone, a decrease of CM maximum output voltage in test frequency from 2 to 6 kHz was observed. (2) N1 potential of AP decreased very significantly by 500 Hz tone exposure. (3) A very pronounced decrease of the absolute value of the negative potential of the EP in 500 Hz exposure was seen.

Combined effects of acute lead acetate exposure and tone exposure of the guinea pig cochlea.

Lead acetate exposure to humans can induce various disorders of the cranial nerves. Although vertigo and sensorineural deafness have been reported in lead workers, the dose effects of lead acetate on the cochlea and eighth cranial nerve are not well documented. We investigated the effects of lead acetate on the male albino Hartley guinea pig cochlea by measuring cochlear microphonics (CM), whole nerve action potential (AP), endocochlear potential (EP) and K+ ion concentration of the endolymph. Animals were given lead acetate by intraperitoneal injection as 20 mg/week for 4 consecutive weeks. A total dose < 80 mg did not induce electrophysiological changes in the cochlea. However, the AP output voltage (N1) decreased if the 80 mg lead acetate treatment was followed by an 80 dB tone exposure at 6 kHz during 24 h. A change was observed in CM and EP but not K+ ion concentration in the scala media.

A comparative study on the effect of pure-tone exposure of the guinea pig cochlea.

Electrophysiological methods were applied to 160 healthy adult male guinea pigs in order to investigate the effects of pure-tone exposure for 24 h on the inner ear. A reduction in cochlear microphonics (CM), action potential (AP) and endocochlear potential was observed following exposure to 110 dB at 100 Hz, 100 dB at 200 and 600 Hz and 95 dB at 2 kHz. The observed K+ endolymphatic concentration during 40 min anoxia remained unchanged. In contrast K+ decreased in control animals and following exposure to pure tones varying from 110 dB at 60 Hz to 85 dB at 2 kHz. These findings indicate that high frequency tones have a greater effect on inner ear functions than those of lower frequency, decreasing the maximum output voltage of CM and AP but not changing K+ endolymphatic concentration.

Effect of 4 kHz tone exposure on the guinea pig inner ear: relation in the change of cochlear microphonics, action potential, electrochemical potential and K+ ion concentration induced by noise exposure.

Using 110 male albino guinea pigs, and applying electrophysiological methods, we investigated the effects of 4 kHz tone at moderate sound pressure level on the inner ear at different exposure times (6, 12, 24 and 48 h). Longer than 12 h exposure to 4 kHz tone had a considerable effect on the hearing, inducing a decrease in the maximum output voltage of cochlear microphonics and an increase in the K+ concentration in the endolymph.

Study of the effect of 350-Hz tone exposure on electrophysiological function of the inner ear of guinea pigs.

The effects of noise exposure were studied in fifty-nine 4- to 5-week-old albino Hartley guinea pigs with normal hearing (body weight 250-300 g). The following experiments and results were carried out: exposure to 350 Hz pure tones at 115 dB for 40 h and exposure to 350 Hz tones at 120 dB for 64 h. In order to investigate the effects of low-frequency tone exposures on the hearing of the guinea pigs, cochlear microphonics (CM), whole nerve action potentials (AP) and endocochlear potentials (EP) were measured. With a high-sound pressure, a decrease was observed in the CM maximum output voltage in the test frequencies of 2, 4 and 6 kHz while the CM threshold (pseudothreshold) of 6 kHz was elevated. Output voltage of the N1 potential of the AP using a 7-kHz tone burst decreased while the threshold of the N1 potential was elevated. An extension of latency and a decrease in the absolute value of the negative potential in EP were also observed.

Effects of high-frequency sound on electrochemical potential using the single-barrel method in guinea pigs.

There are only a few studies investigating the effects of ultrasound on hearing. This paper reports on an experimental investigation on the effect of the long-time exposure to a moderate sound pressure level, high-frequency sound of 16 kHz on the guinea pig inner ear using electrophysiological methods. A decrease of the absolute value of negative potential was observed in the endocochlear potential (EP). The effects of high-frequency sound on EP and electrochemical potential could be explained by a change in the K+ permeability of hair cells.