[Age estimation from tooth attritions of lower incisors--discussion on the "Amano's method"]

As a method of age estimation from teeth we focused our attention on attritions of lower incisors. Using the Amano's method, we took records of tooth attritions in the planted state of 83 subjects whose ages ranged from 14 to 76 years. A positive correlationship was found to exist between the tooth attrition index and the actual age, allowing to establish the following formula which graphically shows a straight line: Y = 8.505X + 26.073 (r = 0.607), where X is the mean of attrition indexes of lower incisors and Y, the estimated age. In our method of age estimation through attrition indexes, we took advantage of probability and confidence interval. In addition, our method was contrasted with Amano's method, a widely used one in Japan.

Simultaneous and separated culture of keratinocytes and fibroblasts on each side of a collagen membrane

We have developed a new cell culture system which is of benefit for the research of dermal-epidermal interaction. In this system, normal human keratinocytes are cultured on the upper surface of a permeable collagen membrane, on the undersurface of which human fibroblasts are simultaneously and separately cultured in a lifted condition. Both the keratinocytes and fibroblasts showed good proliferation and differentiation which were revealed by phase contrast microscopy as well as light and electron microscopies. A permeability test of the collagen membrane used in the present study showed that peptides of less than 30 kDa are able to penetrate through the membrane. Using this system, we estimated the total protein content and cornified envelope formation in the keratinocytes cultured with or without fibroblasts. We found that the total protein and cornified envelope formation were significantly increased when keratinocytes were cultured together with fibroblasts. When keratinocytes were cultured with fibroblasts in the condition of air-liquid interface, synthesis of the cornified envelope was further enhanced. These results indicate that fibroblasts really effect not only the proliferation but also the differentiation of keratinocytes, and the air-liquid interface enhances their effect on differentiation. This bi-phase separated cell culture system is a useful tool for the study of keratinocyte-fibroblast interaction.

Heredity of muscle fibre composition estimated from a selection experiment in rats

The extent to which muscle fibre composition was determined by the genes transmitted from parents was estimated by using successive selections of rats. A foundation population (G0) was established to carry out the selections; it consisted of 100 albino rats which were randomly chosen from heterogeneous stock. The heterogeneous stock was produced by random-mating of three strains, Wistar-Imamichi, Fischer 344 and Donryu. Successive selection for a high percentage of slow twitch fibres (% ST) was made from G0 to the fourth generation (G4). The mean values of % ST changed from 50.0% in G0 to 55.6% in G4. The mean value in G4 was significantly higher than that in G0. The realized heritability in G0-G4 was calculated from the regression of selection response on the cumulated selection differential. The regression coefficient was 0.17 (SEM 0.04). The realized heritability was significantly different from 0 at the 0.05 level. We concluded that in rats about 17% of the variation of muscle fibre composition was determined by the genes transmitted from parents.

Discrepancy between renin mRNA and plasma renin level in angiotensin-converting enzyme inhibitor-treated rats

1. To investigate the role of transcriptional and post-transcriptional factors in increasing renin synthesis secondary to angiotensin-converting enzyme (ACE) inhibitors, we studied the changes in levels of renal renin mRNA, plasma renin and other hormonal factors. 2. Spontaneously hypertensive rats were orally administered 10 mg/kg spirapril or vehicle daily for 3, 14 or 28 days. 3. Plasma renin activity in the spirapril-treated group was significantly elevated compared with that in the vehicle group at any time (P < 0.01). However, there was no significant change in plasma angiotensin II concentration between the two groups. The ratio of renal renin mRNA to beta-actin mRNA in the spirapril-treated group was higher than that in the control group (P < 0.01). 4. At 28 days, plasma renin activity in the spirapril-treated group was significantly elevated compared with that at 14 days (P < 0.05). However, there was no change in renin mRNA between 14 and 28 days after ACE inhibitor administration. 5. Plasma ACE activity in the treatment group was less than that in the control group at any time (P < 0.01). 6. Our study demonstrated a non-proportional change in plasma renin and renal renin mRNA levels. It is suggested that the main determinant of the rate of renin synthesis after administration of an ACE inhibitor may be post-transcriptional factors, and that unknown mechanisms may be involved in the increase in plasma renin level after long-term administration of ACE inhibitor in addition to the short feedback mechanism brought about by the decrease in angiotensin II.

[Drug compliance in the elderly]

In order to clarify the characteristics of elderly patients concerning their attitudes toward taking prescribed medicine, self-reported compliance with prescriptions was compared among different age groups. We performed a survey in 626 outpatients and their attending physicians in 4 of our affiliated hospitals, and analyzed self-reported compliance by the patients to the prescription and their answers to questions related to drug-taking along with the diagnoses and prescriptions reported by the physician. The number of prescribed medicine was 2.3 tablets on the average for patients younger than 40, while 5.1 tablets were prescribed for patients over 70. However, self-reported compliance was best in patients over 70 than in other age groups. Compliance was good in 76% of patients who answered that the amount of medicine was appropriate, while good compliance was lower in those who thought the prescription excessive (67%). Likewise, compliance of patients who had concerns with drug side effects or who were not feeling well under medication was lower than that of patients who felt well under medication. Prescriptions for after lunch were most liable to be forgotten than those for other times of the day. Moreover, a high percentage of elderly patients attended more than 2 departments or medical facilities, and one third of those patients did not inform the physician of the fact suggesting that they were at higher risks of overdosing and unexpected drug interaction. Furthermore, the percentage of patients who did not receive explanation from physicians was higher in the elderly thus demonstrating that elderly patients have quite different characteristics in attitude with regard to medicine from younger age group patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Dysuria in male elderly outpatients evaluated by a questionnaire survey]

We surveyed complaints of dysuria in male elderly outpatients by questionnaire survey. Seven hundred and twenty outpatients (39 aged 30-39, 63 aged 40-49, 170 aged 50-59, 229 aged 60-69, and 219 aged 70 or more) visiting our outpatient internal medicine clinics were asked by a questionnaire about the subjective symptoms of dysuria, including frequencies of nocturia, prolongation of the start of urination, straining at urination, and residual urine, graded as asymptomatic, mild, moderate and severe. The subjects were divided into three groups as to the dysuria; normal group without symptoms or one mild symptom, borderline group with two or more mild symptoms, and dysuria group with one moderate or severe symptom or more. The rates of the patients in the dysuria group were increased with age, being 15%, 16%, 21%, 31% and 53%, respectively, in the above-mentioned age groups. This finding emphasized the importance of questions about dysuria in elderly patients also in internal medicine outpatient clinics, and of differential diagnosis for the causal factor(s) for dysuria in elderly patients including benign prostate hypertrophy.

Hypotensive effect associated with a phospholipase C-δ1 gene mutation in the spontaneously hypertensive rat

To identify the genes responsible for blood pressure in the spontaneously hypertensive rat strain, we performed a cosegregation analysis between the genotype and blood pressure in a set of male F2 rats obtained by crossmating SHR with Wistar-Kyoto rats, a parental normotensive strain. Our investigation revealed that the phospholipase C-delta 1 polymorphism, which resulted in missense mutation, cosegregates with the lower blood pressure in SHR, and that PLC-delta 1 gene is located on chromosome 8. On the other hand, we found the lack of cosegregation between blood pressure and the nerve growth factor receptor gene, which is linked to a hypertensinogenic gene locus (denoted as BP/SP-1) on chromosome 10. We propose that PLC-delta 1 gene itself of closely linked gene on chromosome 8 is a new candidate with the hypotensive effect, and that BP-SP1 locus does not directly contribute to blood pressure elevation in original SHR.

Spectral change in heart rate variability in response to mental arithmetic before and after the beta-adrenoceptor blocker, carteolol

Spectral analysis of heart rate fluctuation was evaluated before and after administration of carteolol, a non-selective beta-adrenoceptor-blocker, to investigate the neural regulatory mechanisms underlying the haemodynamic changes induced by mental stress. Mental stress increased blood pressure and heart rate, with an increased low frequency band, and low frequency/high frequency ratio of the power spectral analysis which are indices of sympathetic activity. Carteolol did not change basal and pre-mental stress measurements of blood pressure, heart rate and spectral density. However, carteolol altered the response to mental stress with a decrease in spectral density of the low frequency band and low frequency/high frequency ratio, and an increase in the high frequency component. These results confirm that mental stress elevates blood pressure by activating the sympathetic nervous system, and suggest that blockade of the beta-adrenoceptor attenuates the pressor response by preventing the autonomic responses to mental stress.

Direct in vivo gene introduction into rat kidney

We established a simple and highly efficient method for in vivo gene transfer using HVJ (Sendai virus) and liposomes. Plasmid DNA and high mobility group 1 (HMG1) protein were co-encapsulated in liposomes by agitation and sonication and were co-introduced into cells by HVJ-mediated membrane fusion. pACT SVT DNA, as a reporter gene, was introduced into the kidney of intact rats through a cannula in the renal artery, and SV40 large T antigen was detected by enzyme immunohistochemistry in glomerular cells 4 days after its introduction. This newly developed kidney-directed gene transfer method should be useful not only in basic research but also in potential gene therapeutics of renal diseases.

Role of cardiac angiotensin II in isoproterenol-induced left ventricular hypertrophy

Angiotensin II (Ang II) has been shown to induce proliferation of cardiac myocytes. To examine the role of Ang II in left ventricular (LV) hypertrophy, isoproterenol was infused subcutaneously into 9-week-old male Wistar rats at 4.2 mg/kg/day for 7 days. Infusion of isoproterenol increased LV weight and Ang II concentrations in plasma and in LV tissue. In anephric rats, LV weight and tissue Ang II were increased similarly, but plasma Ang II was not changed by isoproterenol. Concomitant oral administration of trandolapril and isoproterenol prevented increases in both LV Ang II and LV weight. Treatment with hydralazine decreased blood pressure in a similar way as trandolapril but did not affect either LV weight or LV Ang II. Plasma Ang II was not decreased by either trandolapril or hydralazine when administered in combination with isoproterenol. These results suggest that cardiac tissue Ang II regulates myocyte growth in isoproterenol-induced LV hypertrophy, and the reduction of Ang II partly explains the prevention of cardiac hypertrophy by the converting enzyme inhibitor.

[Effect of antihypertensive treatment in elderly hypertensive patients with cardiac hypertrophy]

In elderly hypertensive patients effect of antihypertensive treatment with Ca antagonist or ACE inhibitor on the heart were examined. Twenty-four elderly hypertensive patients with cardiac hypertrophy, aged 65-79 years old (mean +/- SEM, 71 +/- 1) were treated with Ca antagonist (nifedipine or nicardipine) or ACE inhibitor (captopril or enalapril) for 3 months. Thirteen patients had essential hypertension (EH: SBP greater than or equal to 160 mmHg and DBP greater than or equal to 95 mmHg, 70 +/- 1 years) and 11 had isolated systolic hypertension (ISH: SBP greater than or equal to 160 mmHg and DBP less than 95 mmHg, 74 +/- 2 years). Blood pressure (BP) and heart rate were measured every two weeks. In all patients, M-mode echocardiography was performed to measure left ventricular mass index (LVMI) and ejection fraction (EF), and the sympathetic nervous (plasma norepinephrine and epinephrine) and the renin-angiotensin system (plasma renin activity and aldosterone concentration), were assessed before and after 3 months of treatment. BP significantly decreased from 174 +/- 3/97 +/- 1 to 149 +/- 4/84 +/- 2 mmHg in EH and from 167 +/- 3/82 +/- 2 to 144 +/- 4/74 +/- 2 mmHg in ISH. LVMI was significantly reduced from 204 +/- 14 to 174 +/- 16 g/m2 in EH and from 179 +/- 14 to 156 +/- 12 g/m2 in ISH. EF showed no significant changes in either group. In ISH, the change in LVMI was significantly correlated with the change in systolic BP (r = 0.74, p less than 0.05). In EH, there was no significant relation between BP and LVMI changes.(ABSTRACT TRUNCATED AT 250 WORDS)

[Fresh allograft of intact growth plate into immature articular cartilage defects in rats]

In three inbred rat strains with a distinct major histocompatibility complex (MHC), MHC-matched allografts (Fisher, RT1l to Lewis, RT1l, n = 39) or MHC-mismatched allografts (Brown Norway, RT1n to Lewis, RT1l, n = 38) of fresh intact cartilage obtained from the tibial epiphyseal growth-plate were grafted into the defects in the femoral articular surface of immature rats. In the controls (n = 72), similar defect on the joint cartilage were made with no epiphyseal plate grafts. The present histological observation was continued throughout one year after transplantation. Total success rate of the repair was significantly better in MHC-matched allografts (92%) than in MHC-mismatched allografts (61%, p less than 0.001) or controls (19%, p less than 0.001). The MHC-matched allografts showed no signs of tissue rejection. However, the MHC-mismatched allografts showed evidence of lymphocyte infiltration and 13 (81%) of 16 grafts were rejected from 12 to 48 weeks after operation. These findings indicate that MHC-matched allografts of intact growth-plate have a potential to repair defects in immature articular cartilage over a long period of time, but MHC-mismatched allografts will eventually be rejected.

Radioimmunoassays for melatonin using an antiserum raised against a novel antigen

The highly specific antiserum to melatonin (MT) was produced, and the sensitivity and specificity of the radioimmunoassays (RIAs) using this antiserum was investigated. An immunogen was synthesized by binding 6-hydroxy-melatonin (6-OH-MT) to bovine serum albumin with a spacer of 6-bromohexanoic acid ethyl ester. Rabbits were immunized subcutaneously once a month with 1.0 mg of the immunogen for 7 months. The antiserum was characterized by a crossreactivity test by RIA using 125I-labelled MT. The antiserum specifically recognized MT but hardly did other analogues except for 6-OH-MT with a crossreactivity of only 0.4%. Two RIAs were established using [o-methyl-3H]MT and 2-[125I]iodo MT. In both RIAs, inhibition curves for MT were obtained in the range of 10 pg to 10 ng and 1-2 ng of MT inhibited the value of the assay at "0" by half. The similarity of the RIAs in sensitivity and inhibition by unlabelled MT is discussed on the basis of the structures of radioactive MTs and that of the immunogen.

[Cushing's syndrome found during long-term glucocorticoid treatment of rheumatoid arthritis in an elderly woman]

A 69-year-old female patient had been treated with glucocorticoid for eight years because of rheumatoid arthritis. She showed characteristic Cushingoid features such as central obesity, moon face, and fragility of skin and vessels. She was disabled because of spinal compression fracture and muscle weakness. The blood pressure was 186/100 mmHg and the laboratory tests revealed serum K: 2.8 mEq/l, WBC: 15, 510/mm3, total cholesterol: 310 mg/dl. These suggested that she had iatrogenic Cushing's syndrome. After discontinuation of glucocorticoid, however, the serum cortisol level remained high. This fact prompted us to conduct further examinations for Cushing's syndrome. Oral dexamethasone administration did not suppress the plasma cortisol level and a left adrenal adenoma was found on abdominal CT scan. Because of the presence of bleeding diathesis, operation for adenoma was contraindicated. Though we tried to treat her with metyrapone, trilostane or opeprim (OP'-DDD), we had to abandon specific treatment because of severe side effects such as acute adrenal dysfunction and gastrointestinal problems. Decrease in the endogenous cortisol level after metyrapone treatment caused exacerbation of symptoms of rheumatoid arthritis. This is a peculiar case in which the long-term administration of glucocorticoid for rheumatoid arthritis might have concealed Cushing's syndrome, and conversely the increased intrinsic adrenal steroid hormone might have suppressed the activity of the rheumatoid arthritis.

[An elderly case of hypertension with persistent orthostatic hypotension]

The authors report the successful control of labile hypertension associated with orthostatic hypotension in a 75-year-old male patient, by means of L-DOPS, a synthetic precursor of norepinephrine in combination with antihypertensive drugs. He had been known to be hypertensive for 15 years and developed a persistent floating sensation 2 years age. Despite good control of hypertension after admission, orthostatic hypotension was still observed. Passive tilt produced a blood pressure reduction of 60/20 mmHg. Spectral analysis of heart rate variability showed a disturbance in the activation of the sympathetic nervous system. Treatment with L-DOPS attenuated the blood pressure reduction in response to passive tilt (35/12 mmHg) and improved the sympathetic response. Because of an increase in blood pressure by L-DOPS, addition of either a calcium channel blocker or an angiotensin-converting enzyme inhibitor was necessary. These combinations of treatment successfully controlled blood pressure as well as orthostatic hypotension.

Effect of aging on the renin angiotensin system in patients with renovascular hypertension

The effect of aging on the renin angiotensin system (RAS) was studied in 30 patients with renovascular hypertension and 33 patients with essential hypertension. Plasma renin decreased with age in patients with renovascular hypertension and essential hypertension. However, in patients with renovascular hypertension, the change was not statistically significant. Plasma aldosterone concentration showed a tendency to decrease with age in both groups. Stimulated plasma renin activity and the net increase in plasma renin activity after captopril administration in patients with essential hypertension showed a significant decrease with age. In patients with renovascular hypertension, exaggerated response of renin secretion was observed in younger patients, but middle-aged and elderly patients did not demonstrate this hyper-responsiveness. The degree of decrease in blood pressure by administration of an angiotensin (Ang) II analog ([Sar1,Ile8] Ang II) was the same in both younger and elderly patients with either disease. These results suggest that the effect of aging on the RAS occurs not only in patients with essential hypertension, but also in patients with renovascular hypertension. Furthermore, although the Ang II analog infusion test and captopril stimulation test are considered to be useful screening tests for renovascular hypertension, we consider that the combination of Ang II analog test and captopril test may be favorable to screen renovascular hypertension, since the captopril stimulation test had a lower sensitivity in younger (under 35 years old) patients.

Substrain comparison of genetically hypertensive rats using DNA fingerprinting, and genetic analysis of blood pressure in the inbred rats

Using DNA fingerprinting, genetic heterogeneity or homogeneity was studied between substrains of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats maintained in Japan. Using human myoglobin minisatellite 33.15 as a probe, we did not detect any inter- or intra-substrain genetic heterogeneities in HinfI digests of SHR or WKY rat DNA. However, analysis of Sau3AI digests of rat DNA using mouse C-6 gene as a probe revealed intra-substrain heterogeneity of 1-2 DNA bands in one of the WKY rat substrains. In the other substrains of SHR and WKY rats, there existed no intra-substrain heterogeneities, but several inter-substrain heterogeneities were observed in both SHR and WKY rats. In another experiment using the inbred substrains of SHR and WKY rats which have been confirmed as genetically homogeneous, we produced F1 and F2 rats, and biometrically analyzed their systolic blood pressure. The results suggested that there may be 1-4 dominant antihypertensinogenic genes with high heritability of 0.6-0.7.

Importance of the sympathetic nervous system in blood pressure elevation by subpressor intraventricular NaCl and angiotensin II in the rat

The present study was performed to examine the effect of chemical sympathectomy with guanethidine on the BP change and humoral factors in rats which received continuous and concomitant infusion of i.c.v. hypertonic NaCl with i.v. Ang II, both at subpressor doses for 7 days. Male rats were divided into 3 groups which received the following infusions using an osmotic minipump at a rate of 1 microliter/min: Group 1 (n = 11), 0.15 M NaCl i.c.v. and Ang II (5.4 pmol/kg/min) i.v.; Group 2 (n = 9), 0.8 M NaCl i.c.v. and Ang II i.v.; Group 3 (n = 5), 0.8 M NaCl i.c.v. and Ang II i.v. with daily i.p. injection of guanethidine (40 mg/kg). Significant increase in BP was observed only in Group 2 (from 103 +/- 3 mmHg to 132 +/- 5 mmHg on day 7, p less than 0.001). Addition of i.p. guanethidine to i.c.v. infusion of 0.8 M NaCl and the subpressor dose of Ang II completely prevented increase in the BP, suggesting that the presence of the intact sympathetic nervous system is necessary for the development of BP elevation in response to i.c.v. hypertonic NaCl plus i.v. Ang II. Thus, the sodium status in the central nervous system is important in the regulation of BP and is closely related to the activity of the sympathetic nervous system.

Effect of long-term treatment with an angiotensin-converting enzyme inhibitor on the renin-angiotensin system in spontaneously hypertensive rats

1. To obtain information on regulation of the brain renin-angiotensin system, the effect of long-term administration of angiotensin-converting enzyme (ACE) inhibitor on brain renin and angiotensinogen mRNA was studied. 2. Spirapril (3 mg/kg) was orally administered daily for 8 weeks to spontaneously hypertensive rats (SHR) from 12 weeks after birth. Renin and angiotensinogen mRNA in the brain and kidney were then quantitated by Northern blot analyses with [32P]-labelled rat renin and angiotensinogen cDNA as hybridization probes. Plasma renin activity (PRA), angiotensin II (AII) concentration, plasma ACE activity and brain tissue ACE activity were also measured. 3. Compared with the control group, the Spirapril-treated group had significantly lower blood pressure (P less than 0.01), significantly higher PRA (P less than 0.01), a not significantly different plasma AII concentration, and lower plasma and brain ACE activities (P less than 0.01). Interestingly, the brain renin and angiotensinogen mRNA levels of the two groups were similar, but the renal renin mRNA level was significantly higher in the Spirapril-treated group (P less than 0.01). 4. These results indicate that the mRNA levels of brain renin and angiotensinogen were not affected by chronic ACE inhibition in the circulation and suggest that AII in the brain might not be affected by systemic ACE inhibition.

Characteristics of two lines of guinea pigs (BHS and BHR) differing in bronchial sensitivity to acetylcholine and histamine exposure

In a previous study, we reported that as model animals to be used in the study of bronchial asthma in humans, two lines of guinea pigs were developed by ourselves: bronchial hypersensitive line (BHS) and bronchial hyposensitive line (BHR) as a control. Studies on biological characteristics in guinea pigs of two lines were undertaken, and the following results were obtained. 1) Airway resistance of guinea pigs of the two lines to intravenously administered acetylcholine, histamine and leukotriene D4 was found to be different between BHS and BHR. Airway resistance of BHS to the chemicals was increased compared with those of BHR. 2) The number of muscarinic acetylcholine receptors in lung membrane preparation and its affinity increased significantly in BHS compared with those of BHR. In beta-adrenergic and histamine H1 receptors, there was observed no difference between BHS and BHR. 3) No difference in IgE antibody production to ovalbumin was observed between BHS and BHR. 4) When total leukocytes and differential leukocyte count (percentage, %) in peripheral blood of BHS and BHR were examined, relative percentage of lymphocytes and eosinophils was significantly higher in BHS than in BHR, while percentage of neutrophils was significantly lower in the former than in the latter.