Takashi Kachi

SIMILARITIES AND DIFFERENCES IN SUPPORTING AND CHROMAFFIN CELLS IN THE MAMMALIAN ADRENAL MEDULLAE : AN IMMUNOHISTOCHEMICAL STUDY

Backgrounds: The adrenal medulla is a typical paraganglion, having the same origin as the sympathetic ganglia, and contains at least two types of parenchymal cells: chromaffin cells and supporting cells. We previously reported that the extent of cellular association of chromaffin cells with supporting cells was remarkably higher in noradrenaline (NA)‐than in adrenaline (A)‐cell regions in the adrenal medullae of the rat and pig.

Surgical anatomy of the nuchal muscles in the posterior cervicothoracic junction: significance of the preservation of the C7 spinous process in cervical laminoplasty.

Study Design. An anatomic study investigated the attachment of the nuchal muscles to the spinous process. Objective. To investigate the anatomic details of the attachment of the nuchal muscles to the spinous process, and which muscles are spared, and to what extent, when the C7 spinous process is preserved in the cervical laminoplasty. Summary of Background Data. In previous studies, it was reported that the incidence of postoperative axial pain was lower in C3–C6 laminoplasty than in C3–C7 laminoplasty, emphasizing the effectiveness of the former procedure where discission of the nuchal muscles that are attached to the C7 spinous process is avoided. However, there have been no detailed anatomic studies of the attachment of the nuchal muscles to the spinous process at the cervicothoracic junction. Methods. The anatomy of the speculum rhomboideum of the trapezius, rhomboideus minor, rhomboideus major, serratus posterior superior, splenius capitis, and splenius cervicis to the spinous processes of the cervicothoracic junction were studied using 50 cadavers. Results. The possibility of total discission of the speculum rhomboideum of the trapezius was 0% with C3–C6 laminoplasty and 18% with C3–C7 laminoplasty. More than 50% preservation of the speculum rhomboideum of the trapezius is possible in 72% in C3–C6 laminoplasty and 16% in C3–C7 laminoplasty. In C3–C7 laminoplasty, the possibility of partial preservation of the rhomboideus minor, serratus posterior superior, and splenius capitis at the spinous process was 0%, 66%, and 29%, respectively. The rhomboideus major in 16% and the splenius cervicis in 56% could be completely preserved without partial discission of the muscle attachment. On the other hand, in C3–C6 laminoplasty, the muscles that were spared without complete discission of the muscular attachment at the spinous process were the rhomboideus minor in 35%, the serratus posterior superior in 100% and the splenius capitis in 67%. The rhomboideus major in 76% and the splenius cervicis in 80% were completely spared without partial discission of the muscular attachment. Conclusion. The current study confirmed that C3–C6 laminoplasty in which the C7 spinous process is preserved reduces invasion of the nuchal muscles.

Physiological Pineal Effects on Female Reproductive Function of Laboratory Rats: Prenatal Development of Pups, Litter Size and Estrous Cycle in Middle Age

The present study investigates whether and how the pineal or its hormone melatonin influences female reproductive functions, namely the litter size, prenatal development of offsprings, and estrous cyclicity, especially its age‐related cessation in a non‐seasonal breeder, the laboratory rat. Wistar rats were maintained under a 24 h light‐dark (12L∶12D) cycle. Female rats were divided into 3 groups: non‐operated (NO), sham‐operated (SX), and pinealectomized (PX). Surgeries were performed in 35–40 day‐old females. Starting at an age between 70 days and 7 months, female rats of all 3 groups were repeatedly mated with intact males. PX mothers more frequently delivered pups with malformations (e.g., taillessness, hydronephrosis, 7 out of 1263 pups) than control rats (0/1323; p<0.007). In the first delivery at 3 months of age, but not at later ages, PX mothers delivered more pups of lower body weight than control animals (p<0.001). Examination of vaginal smears showed that almost all female rats of the NO, SX, and PX groups had 4‐day estrous cyclicity when they were young–between 60 days and 5 months of age. At an age of 17 to 18 months, most female rats of the NO and SX groups showed irregular, continuously diestrous or pseudopregnancy‐like patterns, and 4‐day estrous cyclicity was found in only 10% of the NO or SX animals. In contrast, about 50% of the PX rats showed 4‐day estrous cyclicity at this older age (p< 0.001). Melatonin, when added to drinking water (0.4 mg/L) for 16 days during the dark phase increased the frequency of diestrous phase, except in continuously diestrous rats and very few others. This melatonin effect was strong in PX rats but relatively weak in SX rats. In conclusion, the pineal hormone appears to influence various reproductive functions and developmental processes, especially pregnancy and the timing of reproductive aging in rats. The effects of pinealectomy are more prominent at an age of 60 to 80 days (i.e., shortly after puberty) and at the beginning of the cessation of cycles in middle‐aged females.

Differences between adrenomedullary adrenaline and noradrenaline cells: quantitative electron-microscopic evaluation of their differential cellular association with supporting cells.

Quantitative differences in cellular association of adrenomedullary chromaffin cells with other types of cells, mainly supporting cells, were studied. Adrenaline (A) and noradrenaline (NA) cells were compared. Electron micrographs (12000 x) of profiles of A and NA cells, bordering against other types of cells, were used for quantitative evaluation. Supporting cells constituted the majority of the non-chromaffin cell types. Occurrence frequencies of chromaffin cells contiguous with other types of cells were: (1) higher for A cells (68.9%, 199/289) than for NA cells (11.0%, 34/309) in case of small contact regions (χ2-test: P<0.001) and (2) higher for NA cells (68.3%, 211/309) than for A cells (9.7%, 28/289) in case of extended contact regions (P<0.001). In conclusion, the extent of cellular association with supporting cells was remarkably lower in A cells than in NA cells. Such an arrangement is likely to be appropriate for the extensive, homogeneous control and amplified response characteristic of A cells, and for the close range, complex control and more diverse responses characteristic of NA cells.

Differences between adrenaline and noradrenaline cells in cellular association with supporting cells in the adrenal medulla of the pig: an immunohistochemical study.

Location and morphology of glial supporting cells in the pig adrenal medulla were examined immunohistochemically by the ABC method using antibody to S-100 protein. In noradrenaline (NA)-cell regions, S-100-positive cells were located in both marginal and internal portions of the parenchyma, extending fine cytoplasmic processes between NA cells and/or enveloping large surface areas of NA cells. In adrenaline (A)-cell regions, S-100-positive cells were present less frequently than in NA-cell regions, mostly in the marginal portion of the parenchyma. It is surmised that differences between A cells and NA cells in cellular association with supporting cells reflect those in biological characteristics.

Effects of Pinealectomy on the Mitotic Activity of Adrenomedullary Chromaffin Cells in Relation to Time of Day

The frequency of mitoses of adrenaline (A) cells and noradrenaline (N) cells in the adrenal medulla of nonoperated (NO), sham‐operated (SPX), and pinealectomized (PX) male, 53‐day‐old Holtzman rats (n = 133) was investigated by means of light microscopy. Animals were killed at eight time points during a standardized 24‐h light‐dark (12:12) cycle 14 days after surgery. Mitotic indices (n/1,000) were determined in sections of adrenal medulla fixed with glutaraldehyde and OsO4. Overall frequency of mitoses was extremely low (mitotic index: 0.73 = 115/157,223). Daily mean mitotic index was maximum in A cells (0.83) and minimum in N cells (0.52) of PX group but did not show statistically significant differences between cell types or experimental groups. Neither cell type in NO animals showed 24‐h changes in mitotic index, but cells in SPX animals did, with highest value in the late dark phase and lowest in the late light phase, when values of two cell types were combined (P<0.01–0.001). In PX animals, mitotic index followed a similar but more distinct 24‐h change in A cells (P<0.009), but not in N cells, resulting in different time‐of‐day changes between two types of cells (P<0.01–0.05). The mitotic index was higher in PX than in control (NO and SPX) animals in the middark phase (P<0.05) and lower in operated (SPX and PX) than in nonoperated (NO) animals from late light to the early dark phase, suggesting that the latter was possibly due to a residual effect of the surgery. These results are consistent with the interpretation that the pineal has an inhibitory action on A cells and may coordinate the two types of cells in their mitotic activity, especially in the middark phase of the daily cycle.

Rough endoplasmic reticulum in the adrenaline and noradrenaline cells of the adrenal medulla : effects of intracranial surgery and pinealectomy

Abstract: Adrenal medullas in 53‐day‐old rats of the nonoperated (NO) group (n = 31), the sham‐operated (SPX) group (n = 35) and the pinealectomized (PX) group (n = 38) were examined electron microscopically 14 days after surgery. Cell profiles showing solitarily and sparsely distributed rough endoplasmic reticulum (RER) were most frequent in the PX group (daily mean: 66.9%, 427/638), less in the NO (56.0%, 336/600), and least in the SPX (48.5%, 297/612) in adrenaline (A) cells (x2‐test: P < 0.001), while most frequent in the NO group (68.8%, 340/494), less in the PX (64.3%, 303/471), and least in the SPX (57.4%, 256/446) (P < 0.005) in noradrenaline (N) cells. Individual variation was less in A cells than in N cells. Cell profiles showing a large accumulation of RER was more frequent in A cells (N0:8.5%, SPX:13.1%, PX:7.7%) than in N cells (NO:2.8%, SPX:4.5%, PX:4.7%) (controls: P < 0.001). Sham pinealectomy increased a large accumulation of RER in A cells (P < 0.02) and a small aggregation of RER in N cells (P < 0.005) with opposite effects of pinealectomy (P < 0.005, P < 0.025). Pinealectomy decreased a small aggregation of RER without effects of sham pinealectomy in A cells (P < 0.001). Conclusions: (1) Accumulation or aggregation of RER in adrenomedullary chromaffin cells was influenced from the pineal gland either as or without effects of intracranial surgery, and (2) RER in adrenomedullary chromaffin cells showed differences due to cell types.

Quantitative cytological analysis of functional changes in adrenomedullary chromaffin cells in normal, sham-operated and pinealectomized rats in relation to time-of-day. II. Nuclear-cytoplasmic ratio and pars granulosa of nucleolus

Adrenaline(A)- and noradrenaline(N)-cells in the adrenal medulla of nonoperated (NO), sham-operated (SO), and pinealectomized (PX) male rats (n = 125) were investigated by quantitative electron and light microscopy. Animals were killed at eight time points during a standardized 24-h, light-dark (12:12) cycle 14 days after surgery. Nuclear-cytoplasmic (N/P) ratios, diameters of nuclei, and the frequency of nucleoli showing a large amount of pars granulosa (granulated nucleoli), were the primary characteristics studied. Major findings include the following: 1) The frequency of low N/P ratios over a 24-h period tended to be higher in PX animals than in controls in A-cells, as shown in large cell profiles (P less than 0.02); but such a tendency was not apparent in N-cells. Daily mean nuclear diameters were similar among the three experimental groups. 2) The 24-h changing pattern of phase relations in the frequency of low N/P ratio and nuclear size differed between A- and N-cells in NO and SO but not in PX animals. 3) The frequency of granulated nucleoli in A-cells was much higher in PX animals than in NO and SO animals throughout a 24-h period (P less than 0.018), especially from the late light to early dark phase (P less than 0.003), and higher in A-cells than in N-cells generally (P less than 0.0009). Pinealectomy thus caused increases in the cytoplasm and in the pars granulosa of the nucleolus in many A-cells; changes in N-cells were less apparent. This suggest a disturbed balance and coordination between A- and N-cell systems of adrenal medulla following pinealectomy.