Cancerous residue in breast-conserving surgery

Local tumor extension was studied using a continuous series of multiple blocks of mastectomy specimens to assess malignancy remaining after breast-conserving surgery for early-stage breast cancer. In this study, 183 cases were chosen, consisting of 6 noninvasive ductal carcinoma cases and 177 invasive ductal carcinoma cases. The histopathology in 59 (32%) of the 183 cases corresponded to that showing extensions of more than 2.6 cm from the tumor margin. These wide extensions were also seen in 17% of breast cancers with a tumor size of less than 2 cm. The incidence of wide extension was higher in younger patients with cases of noninvasive ductal carcinoma. Extension to the nipple-areola was seen in 14% of cases with a tumor size of less than 2 cm. Breast cancers with multicentric development accounted for 3% of those with a tumor size under 2 cm. These findings suggest that if lumpectomy is performed with a margin of 2 cm for tumors with a size of 2 cm or less, a cancerous residue would be found in the surgical margin of 15-20% of the cases. The actual incidence was 23% of cases after breast-conserving treatment in our study. On the basis of the data, breast-conserving treatment with only local resection of the primary lesion showed cancerous residue such as intraductal cancerous extension in about 20% of cases. Therefore, it was concluded that, as part of breast-conserving therapy of early-stage breast cancer, radiation therapy of the whole breast should be performed after surgery with clear margins to control local recurrence.

Local cerebral glucose utilization in the interictal state of the spontaneously epileptic rat (SER)

Local cerebral glucose utilization (LCGU) in spontaneously epileptic rats (SER) and in their parent strains, zitter (ZI) and Kyoto-Wistar (KW) rats was studied by autoradiography with [14C]2-deoxyglucose. Compared to the LCGU in age-matched KW rats, LCGU in 8-week-old SERs, which had not yet exhibited epileptic seizures, was low in all brain regions examined, and there were no significant differences among the regions. Moreover, there were no differences in LCGU among all regions examined in both SERs and in ZI rats. By contrast, the interictal LCGU in 13-week-old SERs, which did exhibit epileptic seizures, was generally lower than in the other two strains, particularly in the hippocampus and amygdala. These findings suggest that the epileptogenic focus in SERs may lie in the hippocampus and amygdala.

The characteristics of interval breast cancer in mass screening

To investigate the characteristics of interval breast cancer in mass screening, comparisons were made of the following three groups: interval group (21 interval breast cancer cases), mass screening group (87 breast cancer cases detected by mass screening) and outpatient group (266 breast cancer cases diagnosed at outpatient clinics). There were no differences among the three groups in terms of the case distribution by age or obesity, but significant differences in the case distribution according to nodal involvement and tumor size. Histological grading of the malignancy of the primary tumors disclosed that the incidence of breast cancer showing frequent mitoses was high in the interval group compared to the mass screening and outpatient groups. The 7-year cumulative disease-free survival rate was 75.3% in the interval group, 90.0% in the mass screening group and 83.1% in the outpatient group. The mean tumor size of the interval cases at the time of mass screening, back-calculated on the basis of the estimated tumor doubling time, was 1.5 cm in diameter, smaller than that of the mass screening group. It is surmised that interval breast cancer is characterized by marked proliferation of the tumor cells and has a poorer prognosis than the other group cases. These findings might be due to the marked proliferation of interval breast cancer rather than because of cases having been overlooked at the time of the last screening.

Antiepileptic effects of CNK-602A, a novel thyrotropin-releasing hormone analog, on absence-like and tonic seizures of spontaneously epileptic rats

The effects of CNK-602A (N-[(6-methyl-5-oxo-3-thiomorpholinyl) carbonyl]-L-histidyl-L-prolinamide), a novel thyrotropin-releasing hormone related analog, were investigated on absence-like seizure and tonic convulsion in the spontaneously epileptic rat (SER), which is a genetically defined double-mutant. When CNK-602A of 0.2-1 mg/kg was given intravenously to the animal, there were no changes in the background EEG except for an increase in low-voltage fast waves concomitant with behavioral alertness. However, CNK-602A suppressed absence-like seizure and tonic convulsion in a dose-dependent manner for over 1 h. These antiepileptic effects of CNK-602A on both seizures were antagonized by pretreatment with haloperidol (1 mg/kg, i.p.). It was found, using a brain in vivo microdialysis method, that CNK-602A at a dose of 1 mg/kg, which inhibits the seizures, increased the release of dopamine in the caudate nucleus. These results suggest that CNK-602A inhibits the seizures of SER in a similar manner to thyrotropin-releasing hormone (TRH), probably by increasing the release of dopamine in the central nervous system. In addition, the antiepileptic effects of CNK-602A were more potent and lasted longer than those of TRH.

[A comparative analysis of interval breast cancer with breast cancer detected by mass screening or in outpatient clinics]

To investigate the characteristics and the prognosis of interval breast cancer, 21 interval cases were reviewed and compared with a total of 87 patients with breast cancer detected by mass screening and 266 found in outpatient clinics on the basis of the clinicopathological features. The postoperative cumulative 7-year disease-free rates were 61.1%, 81.4% and 69.0% in the interval cases, mass screening cases and outpatient clinic cases, respectively. The percentage of cases showing frequent mitoses in cancer cells was statistically higher for interval cancer than for the other breast cancers. The average tumor size of the interval cases calculated from the speculated tumor doubling times, was 1.51 cm. It is surmised that interval breast cancer is characterized by a marked proliferation of tumor cells and has a poorer prognosis than the other breast cancers. This might be due to the marked proliferation of interval breast cancer rather than under-counting because there were no malignant findings at the time of the last screening.

A rare case of fibroadenoma in a tubular adenoma of the breast

We report herein a case of a 31 year old housewife who underwent an excisional biopsy for a well-circumscribed lump in her breast. The lump contained 2 histological patterns, namely, fibroadenoma and tubular adenoma. These patterns had no transitional zone, were distinct and changed abruptly. This case was histologically diagnosed as "a fibroadenoma in tubular adenoma of the breast, benign", with no other such case ever having been reported in Japan. The histological findings of this case, convinced us that tubular adenoma is closely related to fibroadenoma.

Effects of L-threo-DOPS, a noradrenaline precursor, on the long-term potentiation in the rat hippocampal mossy fiber-CA3 region

The effects of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS), a synthetic precursor of norepinephrine (NE), on the long-term potentiation (LTP) in the hippocampal mossy fiber-CA3 system was examined in urethane-anesthetized rats, the objective being to determine whether or not this drug acts as NE on the LTP. L-threo-DOPS may be effective for treating some type of mental disorders, including dementia. The LTP, induced in CA3 by tetanic stimulation (100 Hz for 1 s) applied to the mossy fiber persisted for more than 4 h. When L-threo-DOPS (50 and 150 micrograms) was injected into the lateral ventricle 30 min prior to the tetanic stimulation, there were no significant alterations in the LTP. However, in animals treated with reserpine (5 mg/kg i.p.) 24 h before the experiment, LTP was not induced with tetanic stimulation alone yet was obtained when tetanic stimulation was preceded by L-threo-DOPS (50 and 150 micrograms) applied to the ventricle. The LTP obtained by L-threo-DOPS in the reserpine-treated animal was inhibited by pretreatment with benserazide and was completely blocked by the simultaneous administration of sotalol. These results suggest that NE converted from L-threo-DOPS plays an important role in inducing LTP in the mossy fiber-CA3 system in the animals deficient in catecholamines.

Short- and long-term effects of transection of the ophthalmic nerve on optokinetic nystagmus in the rabbit

The role of extraocular proprioception in optokinetic nystagmus (OKN) was examined, using adult pigmented rabbits following transection of the ophthalmic branch of the trigeminal nerve. OKN was induced by rotation of a drum at an angular velocity of 0.85 and 3.7 degrees/s. The eye on the operated side showed a delay in the transition from the OKN-induced quick phase to the slow phase regardless of closure of the eye on either the operated or unoperated side. In addition, the eye on the operated side showed an anticompensatory response in the vestibulo-ocular reflex (VOR) with an unstable drift in the dark. The above abnormalities in OKN and VOR following rhizotomy disappeared after 1-1.5 months. These results suggest that proprioception in the extraocular muscle plays an important role in the fine regulations of eye position for gaze accuracy. The recovery demonstrated appears to be due to a compensatory mechanism in the central nervous system.

Characteristics of muscarinic cholinergic, gamma-aminobutyric acid(A) and phencyclidine receptors in spontaneously epileptic rats; in vitro quantitative autoradiographic analysis

Characteristics of muscarinic cholinergic (mACh), gamma-aminobutyric acid(A) (GABAA) and phencyclidine (PCP) receptors in the spontaneously epileptic rats (SER), which exhibit both absence-like seizures and tonic convulsion, were examined using in vitro quantitative autoradiography. Computer analysis using autoradiographic technique revealed that the amount of the specific binding of [3H]quinuclidinyl benzilate (QNB) to mACh receptors in the striatum of SER was more than that of zitter rats, not exhibiting both seizures and convulsion. However, the specific bindings of [3H]muscimol and [3H]N-(1-[2-thienyl]cyclohexyl)3,4-piperidine (TCP) to GABAA and PCP receptors, respectively, of SER were not different from those of zitter rats in various regions tested. These results suggest that hyperfunction of mACh receptors in the striatum is involved in the appearance of absence-like seizures and tonic convulsion of SER.

Effects of thyrotropin-releasing hormone and a related analog, CNK-602A, on long-term potentiation in the mossy fiber-CA3 pathway of guinea pig hippocampal slices

The effects of thyrotropin-releasing hormone (TRH) and a related analog, CNK-602A, that induces the release of catecholamines, on long-term potentiation (LTP) of the population spike in mossy fiber-CA3 pathways were investigated in guinea pig hippocampal slices. TRH augmented LTP of the population spike at concentrations of 10(-6)-10(-5) M. CNK-602A also augmented LTP at concentrations of 10(-6)-10(-5) M in a dose-dependent manner. LTP in slices of the hippocampus obtained from animals given 6-hydroxydopamine (6-OHDA) intraventricularly was significantly lower than that in non-treated animals. However, both TRH and CNK-602A (10(-6) M) augmented LTP in slices from 6-OHDA-treated animals. These findings suggest that TRH and CNK-602A augment LTP in the mossy fiber-CA3 pathway without activating noradrenergic and/or dopaminergic fibers.

Inhibition of lateral vestibular nucleus neurons by 5-hydroxytryptamine derived from the dorsal raphe nucleus

Electrophysiological studies were performed to elucidate the effect of 5-hydroxytryptamine (5-HT) originating in the dorsal raphe nucleus (DR) on neuronal activity in the lateral vestibular nucleus (LVN) neurons, using cats anesthetized with alpha-chloralose. LVN neurons were classified into monosynaptic and polysynaptic neurons according to their responses to vestibular nerve stimulation. Conditioning stimuli applied to the DR inhibited orthodromic spikes elicited by vestibular nerve stimulation predominantly in polysynaptic neurons of the LVN. The iontophoretic application of 5-HT also inhibited orthodromic spikes of the LVN neurons. A close correlation was observed between the effects of DR conditioning stimulation and iontophoretically applied 5-HT in the same neurons. These inhibitions with both treatments were antagonized during the application of methysergide, a 5-HT antagonist. In the majority of LVN polysynaptic neurons that responded to antidromic stimulation of the ipsilateral or contralateral abducens nucleus, orthodromic spikes elicited by vestibular nerve stimulation were inhibited by DR conditioning stimulation and the iontophoretic application of 5-HT. In contrast, LVN neurons that responded to antidromic stimulation of the vestibulospinal tract were rarely affected by these treatments. These results indicate that 5-HT derived from the DR inhibits the synaptic transmission of LVN polysynaptic neurons ascending to the abducens nucleus, and suggest that 5-HT derived from the DR is involved in the regulation of the vestibulo-ocular reflex.

Ontogeny of absence-like and tonic seizures in the spontaneously epileptic rat

The ontogeny of epileptic seizures in spontaneously epileptic rats (SER; zi/zi, tm/tm) was studied by examining behaviour and electroencephalogram (EEG) simultaneously. Weight gain and survival time were also studied. Compared with the control Kyo:Wistar rats, SER showed a much smaller increase in body weight. All male and female SER died before 20 and 18 weeks of age, respectively. Body tremor was observed at 2 weeks of age but disappeared after 11 weeks. Staggering gait appeared after 7 weeks of age, and intensified with age. Absence-like seizures characterized by paroxysmal appearance of 5-7 Hz spike-wave-like complexes were observed in the cortical or hippocampal EEG after 5 weeks of age, and tonic seizures with low voltage fast waves were observed after 6 weeks of age. All SER exhibited both absence-like and tonic seizures with high frequencies from 12 weeks of age. Differences with other spontaneous rat models of epilepsy and application methods for estimating seizure-inhibitory effects of anti-epileptic drugs are discussed.

Inhibition by thyrotropin-releasing hormone of epileptic seizures in spontaneously epileptic rats

The effects of thyrotropin-releasing hormone (TRH) were investigated on absence-like seizures, which are characterized by the sudden appearance of 5-7 Hz spike-wave-like complexes in the cortical and hippocampal EEG, and on tonic convulsions of spontaneously epileptic rats (SER; zi/zi, tm/tm), a double mutant obtained by mating zitter homozygote (zi/zi) with tremor heterozygote rats (tm/+). TRH (5 and 10 mg/kg i.v.) inhibited the appearance of both absence-like seizures and tonic convulsions of SER without inducing obvious changes in the background EEG. The inhibitory effects were seen 5-20 min after injection of 10 mg/kg TRH and were antagonized by pretreatment with haloperidol (0.5 and 1.0/kg i.p.), although haloperidol alone did not affect the seizures. These results suggest that TRH has an antiepileptic effect in the genetically defined animal model, SER, and that the effect is mediated by the central dopaminergic system.

Correlation between estrogen receptor status and histological malignancy in human breast cancer

Sixty-two breast carcinoma patients underwent mastectomy and were analyzed for correlations between estrogen receptor (ER) status of the tumor and the histological findings of tumor, age, nodal status, and tumor size. An immunocytochemical assay for the detection of ER in breast carcinomas was used to evaluate the staining intensity index (SII) of the ER level of the tumors, which was calculated from the staining intensity of cancer cells and the percentage of ER-positive cancer cells. The histological differentiation of carcinomas showed a strong correlation with the SII. A statistically significant (F = 10.580, P less than 0.0005) negative correlation was found between the grade of malignancy and the SII. Patients under 50 years of age tended to have a lower SII, whereas patients over 49 years of age tended to have a higher SII. The tumor size, and nodal status showed no correlations with the SII in any of the patients. The histological differentiation of the tumor cells showed a strong correlation with the heterogeneity of the distribution of ER-positive cells in breast cancers.

Effects of anti-vertigo drugs on medial vestibular nucleus neurons activated by horizontal rotation

The effects of anti-vertigo drugs on medial vestibular nucleus (MVN) neurons were examined to assess the site and mode of action using cats anesthetized with alpha-chloralose. Single neuron activity in the MVN was extracellularly recorded using a silver wire microelectrode attached along a seven-barreled micropipette, each of which was filled with diphenhydramine, diphenidol, betahistine, glutamate or NaCl. Type I of the MVN neurons were identified according to the responses obtained when the animal placed on a turn-table was rotated sinusoidally. The effects of the drugs were examined on type I neurons which received impulses primarily from the labyrinth and sent them to the oculomotor nuclei. The microiontophoretic application of diphenhydramine, diphenidol and betahistine inhibited rotation-induced firing of type I MVN neurons. Diphenhydramine and diphenidol were more potent than betahistine. These results suggest that these drugs directly act on MVN neurons to reduce the responsiveness to rotatory stimulation.

Inhibition by talipexole, a thiazolo-azepine derivative, of dopaminergic neurons in the ventral tegmental area

A microiontophoretic study using rats anesthetized with chloral hydrate and immobilized with gallamine triethiodide was carried out to compare the effect of talipexole (B-HT 920 CL2:2-amino-6-allyl-5,6,7,8-tetrahydro-4H-thiazolo [4,5-d]-azepine-dihydrochloride), a dopamine autoreceptor agonist, on dopaminergic neurons in the ventral tegmental area (VTA) to non-dopaminergic neurons in the VTA. VTA neurons were classified into two types according to the responses to antidromic stimulation of the nucleus accumbens (Acc): type I neurons with a long spike latency (8.69 +/- 0.24 msec) upon Acc stimulation and low spontaneous firing rate (6.80 +/- 1.34/sec), and type II neurons with a short latency (2.76 +/- 0.20 msec) and high spontaneous firing rate (26.77 +/- 7.05/sec), probably corresponding to dopaminergic and non-dopaminergic neurons, respectively. In type I neurons, microiontophoretic application of talipexole and dopamine inhibited antidromic spike generation elicited by Acc stimulation, and talipexole-induced inhibition was antagonized by domperidone (dopamine D-2 antagonist). In type II neurons, however, the antidromic spikes were not affected by either talipexole or dopamine. Furthermore, spontaneous firing was also inhibited by iontophoretically applied talipexole and dopamine in most type I neurons, but rarely affected by either drug. Inhibitory effects of talipexole were antagonized by domperidone. These results suggest that talipexole acts on dopamine D-2 receptors, thereby inhibiting the dopaminergic neurons in the VTA.

Dopamine D-1 receptor-mediated inhibition of nucleus accumbens neurons from the ventral tegmental area

1. Spike generation by stimulation of the parafascicular nucleus of thalamus was extracellularly recorded in the nucleus accumbens of chloral hydrate-anesthetized adult Wistar rats using a silver-wire microelectrode attached along a seven-barreled micropipette, each of which was filled with dopamine, SKF 38393 (D-1 agonist), bromocriptine (D-2 agonist), haloperidol, SCH 23390 (D-1 antagonist) and domperidone (D-2 antagonist). The drugs were microiontophoretically applied to the target neurons recorded. 2. Effects of dopamine receptor antagonists on the inhibition of the spike generation by conditioning stimuli applied to the ventral tegmental area preceding the test stimulus to the parafascicular nucleus and those of dopamine agonists on the test stimulus-induced spikes were examined. 3. The parafascicular nucleus stimulation-induced spikes were inhibited by dopamine as well as D-1 and D-2 agonists and by the conditioning stimulation of the ventral tegmental area. The conditioning stimulation-induced inhibition was antagonized by haloperidol and SCH 23390, but not by domperidone. 4. Activation of D-1 receptors, which make probably synaptic contact with dopaminergic nerve terminals from the ventral tegmental area, is considered to result in inhibition of the neuronal activity of the nucleus accumbens neurons receiving input from the parafascicular nucleus of the thalamus. In addition, D-2 receptors located extrajunctionally may be involved in the inhibition of the same neurons in the nucleus accumbens.

Inhibition by intravenously administered sodium bicarbonate of neuronal activity in medial vestibular nucleus neurons

The effects of 7% sodium bicarbonate on medial vestibular nucleus (MVN) neurons were examined to elucidate the mechanism underlying its anti-vertigo action, using alpha-chloralose-anesthetized cats. Intravenous injection of the drug at 1, 2 and 4 ml/kg every 10 min dose-dependently inhibited rotation- and glutamate-induced firing of type 1 neurons, although a low dose of the drug enhanced firing in a few neurons. However, microiontophoretic application of bicarbonate ions did not inhibit rotation- or glutamate-induced firing. After injection of the drug, the Po2 level in arterial blood did not differ from previous levels, but the bicarbonate ion levels dose-dependently increased concomitantly with an increase in pH, as compared with previous levels. These results suggest that the intravenous injection of 7% sodium bicarbonate directly inhibits the neuronal activity of the MVN, although the lower dose may enhance neuronal activity by acting on the peripheral vestibule.

Chemoendocrine therapy in DMBA-induced rat mammary carcinoma

In the present study, chemotherapy with 5-fluorouracil(5-Fu), endocrine therapy with tamoxifen (TAM), and chemoendocrine therapy with concominant use of 5-FU and TAM were performed and compared for DMBA-induced rat mammary carcinoma, a hormone-dependent tumor. The study was designed to assess the usefulness of chemoendorine therapy based on the antitumor effects and changes in hormone receptor levels. The response rates in the groups treated with 5-Fu or TAM alone and the combination of 5-Fu and TAM were 60%, 50% and 62%, respectively. There was no difference in these response rates. The tumor regression rates in these treatment groups were 22 +/- 69%, 20 +/- 54% and 46 +/- 37%; again there was no difference among the three groups. After treatment, the estrogen receptor (ER) and progesterone receptor (PgR) levels decreased significantly in the groups treated with TAM alone and the combination of 5-FU and TAM but remained unchanged in the group treated with 5-FU alone. The decreases in the ER and PgR levels in responsive tumors after treatment were considerably greater in the groups greated with TAM alone and the combination of 5-FU and TAM than in the group treated with 5-FU alone. However, the changes in the receptor levels in nonresponsive tumors did not differ among the three treatment groups. Moreover, there were no differences in the antitumor effects and changes in receptor levels between the groups treated with TAM alone and the combination of 5-FU and TAM. These results suggest that the antitumor effect observed in the combination therapy with 5-FU and TAM was mainly due to the action of TAM. In brief, the expected additive effects of chemoendocrine therapy were not observed.

A patch clamp study of muscarinic excitation of the rat adrenal chromaffin cells

A patch clamp study was performed to determine the ionic mechanisms underlying the muscarinic excitation of rat adrenal chromaffin cells. Burst-like, single-channel currents with brief openings were recorded during cell-attached or cell-free patch recording when the pipette solution contained high K+ media (70-140 mM), and the currents were recorded at potentials near the resting membrane potential. The amplitude and frequency of channel openings were dependent on the membrane potential and the K+ concentration of the external medium. Moreover, the single-channel currents observed with high K+ outside the membrane during inside-out recording were suppressed by the addition of a K+ channel blocker, tetraethylammonium, inside the membrane. These results suggest that the single K+ currents recorded in the present study had properties similar to those of the resting or muscarine-activated K+ currents in atrioventricular cells of the rabbit heart. During cell-attached patch recording with the high K+ medium in the recording pipette, muscarine at concentrations of 10(-5) to 10(-4) M dose dependently decreased the frequency of the channel openings but did not affect the current-voltage relationship or the time constants of open and close time histograms. These results indicate that muscarinic-induced suppression of K+ currents is caused by a decrease in the number of active K+ channels at the resting membrane potential.

Voltage and current clamp studies of muscarinic and nicotinic excitation of the rat adrenal chromaffin cells

Characteristics of the muscarinic and nicotinic excitation of chromaffin cells that had been freshly isolated from the rat adrenal medullae were analyzed using voltage and current clamp techniques. A dose-dependent increase in the extracellularly recorded firing of cells was observed when 10(-6) to 10(-4) M acetylcholine (ACh) were locally applied to the cells in the vicinity of the target cell being recorded using a microinflow method. During voltage clamp recording at the resting membrane potential, ACh induced two different sequential inward currents: a transient current with a rapid rising phase (fast response) and an apparent inward current with a slow rising phase (slow response). The membrane conductance increased during the ACh-induced fast response, and it subsequently decreased during the slow response. The amplitude of the fast response decreased when the holding potential was shifted to depolarized levels, whereas the amplitude of the slow response increased with depolarization. Nicotine produced fast depolarization and a transient inward current that was reduced by the membrane depolarization. In contrast, muscarine induced a slow depolarization and an apparent inward current that increased with depolarization. Muscarine also reduced the inward K+ current that had been induced by the application of a high K+ medium to the outside of the cell at the resting membrane potential. It is suggested that muscarinic excitation is triggered by the suppression of K+ channels that are open at potentials near the resting membrane potential. The present results indicate that ACh-induced excitation of adrenal chromaffin cells involves two separate mechanisms mediated by nicotinic and muscarinic receptors.

Studies on the chironomid midges (Diptera, Chironomidae) of the Nansei Islands, southern Japan

The Nansei Islands are located in the subtropical zone of the western Pacific Ocean between Kyushu and Taiwan, and are composed of the two main island groups, the Amami and the Ryukyu Archipelagoes. This area has been known for the presence of a number of indigenous animal species. Prior to the present studies, collections of the chironomids mainly in the urban areas of the three main islands of the Ryukyus were carried out by Sasa and Hasegawa, and a total of 42 species, including 25 new species, were recorded. Additional collections of the chironomids mainly in the mountainous areas of this region were carried out by the present author during 1988 and 1989, and a total of 26 species (including 12 new species) were recorded from Amami Island, and a total of 27 species (including 10 new species) were recorded from the Ryukyu Islands. Eight species among them, including 3 new species, were common to the two archipelagos.