不同年龄和部位女性皮肤微循环变化

目的观察不同部位皮肤血管结构和形态差异,研究年龄对真皮微循环功能的影响.方法采用活体电视毛细血管镜(Intravital Video-capillaroscopy)和激光多谱勒血流仪(laser Doppler flowrnetry)对50名年龄在20～74岁,光皮肤类型为Ⅱ～Ⅲ型白人女性志愿者的前额、眼角、前臂内侧和手背血管作初步观察.并用计算机图象处理技术,对前臂和手背活体真皮血管密度作定量分析.结果真皮乳头毛细血管襻在活体电视毛细血管镜下为点状或逗点状;乳头下的血管丛表现为线条状或网状;年轻人皮肤血管排列整齐,年龄较大者血管扩张增粗、扭曲,排列不规则.年龄与襻状血管数、襻状血管面积显著负相关;与襻状血管间距、平行血管总长正相关;真皮血流量面部高于肢端;随年龄的增加真皮血流有逐渐增加趋势.结论年龄影响真皮微循环的形态和功能.两种无创性检测技术联合应用能动态研究活体真皮血管的形态和结构,在皮肤血管性疾病的诊断和治疗方面有较高的应用前景.     

Ambulatory Electrocardiography for the Detection of Pacemaker Lead Failure

The suboptimal performance of some polyurethane bipolar pacing leads has highlighted concern about the optimal method of monitoring pacemaker lead performance. Since the manifestations of premature lead failure may be initially intermittent, we hypothesized that ambulatory electrocardiography (AECG) would be a more sensitive tool for the detection of pacing lead failure compared to increased pacemaker clinic surveillance. Since the Medtronic safety alerts on the 4012, 4082, and 4004 leads, we have followed 261 patients by serial AECG and 165 patients by increased pacemaker clinic surveillance. Lead failures were identified in 75 patients: 68 in the AECG group (31 %) and 7 in the clinic group (4%, P < 0.001). Repeat AECG confirmed the lead failure in 38 (97%) of 39 patients in which it could be done. Pacing lead failure documented by AECG could be confirmed by a subsequent clinic assessment in only 15 (25%) of 60 patients evaluated (P < 0.001). The actuarial survival of the 4012 lead was significantly lower in the AECG group compared to the clinic group (56% vs 87% survival at 8 years, P < 0.002). Similar trends were observed for the 4082 and 4004 leads. AECG is a more sensitive method of surveillance for pacemaker lead function compared to pacemaker clinic assessment. AECG should be incorporated into the routine follow-up of pacemaker patients. (PAGE 1997; 20[Pt. I]:127 4-1282)     

HETEROGENEITY IN ADRENAL STEROIDOGENESIS IN NORMAL MEN AND WOMEN

Adrenal steroidogenesis has been studied in vivo in normal men and women. Serum levels of nine steroids on the biosynthetic pathway (the delta 5 3-beta-hydroxysteroids, pregnenolone (Pe), 17 alpha-hydroxypregnenolone (17Pe), dehydroepiandrosterone (DHEA), androstenediol (Adiol), and their delta 4 3-keto counterparts, progesterone (Po), 17 alpha-hydroxyprogesterone (17Po), androstenedione (Adione), and testosterone (T)) as well as cortisol were measured during adrenal suppression and stimulation. This study demonstrates a marked heterogeneity in adrenal steroid responses between different subjects in the normal population. Thus, in three subjects ACTH stimulation from a dexamethasone-suppressed state resulted in a far greater increment of 17Po than in the other nineteen normal subjects. These three individuals (designated Type 2 responders) may have a partial deficiency of 21-hydroxylase activity. In the remaining nineteen subjects (designated as Type 1 responders) the women had a greater increment of Adiol (P less than 0.05) and a lower increment of Po (P less than 0.01) than the men, suggesting that adrenal 3-beta-hydroxysteroid dehydrogenase/isomerase activity may be slightly lower in women than men.     

ADRENAL PROGESTERONE, 17α-HYDROXYPROGESTERONE AND CORTISOL RESPONSES TO SYNACTHEN IN NORMAL WOMEN AND WOMEN WITH VARIOUS GYNAECOLOGICAL DISORDERS

In apparently normal subjects there is marked heterogeneity in the adrenal's capacity to produce the progestogens progesterone (Po) and 17α-hydroxyprogesterone (17Po). We have now screened for the possibility that adrenal progestogens might be an aetiological factor in some patients with hitherto unexplained gynaecological disorders by measuring the responses to acute stimulation with ACTH after overnight dexamethasone suppression. Plasma progesterone (Po), 17α-hydroxyprogesterone (17Po), and cortisol were assayed in 65 gynaecologically normal women and in 187 with a variety of gynaecological problems including dysfunctional uterine bleeding, unexplained primary infertility, endometriosis, polycystic ovaries, idiopathic hirsutism, and premenstrual syndrome. Responses to ACTH were compared with those in normal subjects according to predominant diagnostic category or categories. There was a wide spectrum of progestogen response to Synacthen in all groups with close agreement between the 30- and 60-min increments in the serum levels for any one steroid. The test was reproducible from one cycle to the next for 17Po (a relatively weak progestogen) and cortisol but much less so for the strong progestogen Po. This variability was not due to spontaneous fluctuation in dexamethasone-suppressed serum Po levels and remains unexplained. The 60-min Po and 17Po increments tended to increase slightly with age. Overall, the 60-min Po increments were a little higher amongst the patients with unexplained primary infertility than amongst controls. There were no significant differences in 17Po increments between normal women and patients, with an equal incidence of marked hyperresponse (exceeding 6 nmol/l increment) in both populations. Unexpectedly, the 18 patients complaining of severe premenstrual symptoms had significantly lower cortisol responses than other groups. We conclude that except in overt 21-hydroxylase deficiency, adrenal progestogens are unlikely to be a major factor in causing gynaecological disorders.     

Inhibition profiles of sodium cromoglycate and nedocromil sodium on mediator release from mast cells of human skin, lung, tonsil, adenoid and intestine

We have studied an aspect of the functional heterogeneity of human mast cells, namely responsiveness to the inhibitory effects of sodium cromoglycate and nedocromil sodium. The effects of these drugs were examined on the release of histamine and PGD2 from mast cells of human skin, lung, tonsils, adenoids and intestine. A high concentration, 1000 microM, of sodium cromoglycate was required to significantly inhibit histamine release from lung and tonsillar mast cells. Nedocromil sodium, 1000 microM, was more effective than sodium cromoglycate against histamine release from lung, tonsillar and adenoidal cells. Both compounds showed tachyphylaxis in lung and tonsillar mast cells but not in adenoidal and intestinal mast cells. In contrast, in intestinal mast cells, the effect of nedocromil sodium was weaker and more variable than sodium cromoglycate. Skin mast cells differed from mast cells of the other anatomical sites in being unresponsive to sodium cromoglycate and nedocromil sodium. Our results confirm that high concentrations of sodium cromoglycate and nedocromil sodium are required to achieve even modest inhibition of mediator release from human mast cells under in vitro conditions. Notwithstanding this, the results also indicate that differences exist among skin, lung, tonsillar, adenoidal and intestinal mast cells with respect to their sensitivity to sodium cromoglycate and nedocromil sodium, thus extending our knowledge of functional heterogeneity within the human mast cell populations.     

The Prevalence of Hyperlipidaemia and Related Clinical Features in Insulin-dependent Diabetes Mellitus

SUMMARY The Prevalence of hyperlipidaemia and related clinical featureswas examined in 205 individuals with insulin -dependent diabetesmellitus. Overall, 40 per cent (82) of the individuals had hyperlipidaemia.Whilst the prevalence of hypertriglyceridaemia and combinedhyperlipidaemia was greater in patients with insulin-dependentdiabetics, mellitus than non-diabetics, this was not the casefor hypercholesterolaemia. Hyperlipidaemia was present in olderpatients, and the daily insulin dose and levels of HbA₁ werehigest in those with combined hyperlipidaemia. In addition normolipidaemicsubjects had the lowest levels of serum creatinine. Triglyceridelevels were predicated (in order of importance) by insulin dose,age at diagnosis, HbA₁ and body. mass index, whilst cholesterollevels were predicted by the age at the time of study, bodymass index, Urinary protein excretion, and levels of fastingblood gluciose and HbA₁. Hyperlipidaemia is common in insulin-dependent diabetes mellitus,and may be particularly apparent in older patients and/or thosewith early renal dysfunction or poor glycaemic control.     

CIRCULATING BIOACTIVE FOLLICLE STIMULATING HORMONE AND IMMUNOREACTIVE INHIBIN LEVELS DURING THE NORMAL HUMAN MENSTRUAL CYCLE

To examine the relationship between circulating levels of bioactive FSH (B-FSH) and immunoactive inhibin and oestradiol we studied five women during ovulatory cycles. Daily blood samples were collected from each subject during one menstrual cycle. B-FSH was measured using a modified, highly sensitive in-vitro rat granulosa cell bioassay. The inclusion of IGF-1 (10 μg/1) and transferrin (50 mg/I) in the assay system enhanced granulosa ceil responsiveness to FSH and resulted in increased assay sensitivity. Inhibin was measured by a heterologous radioimmunoassay (RIA) using an antibody raised against 31 kDa bovine inhibin. Bioactive FSH (B-FSH) levels were closely correlated to those of immunoactive FSH (I-FSH, r = 0.79, P<0001) throughout the cycle. Peak levels of B-FSH were observed during the early follicular phase (day –13, 44.7 ± 9.6 IU/1, mean ± SEM) and during the midcycle surge (35.2 ± 6.2 IU/1); lowest levels occurring during the luteal phase (nadir 3.9 ± 0.27 IU/1). Plasma oestradiol levels increased significantly during the follicular phase (P<0.001) to a peak on day – 1 and were negatively correlated with B-FSH during the late follicular phase (day –8 to – 1; r= –0.45. P<002). There was no change in the concentration of inhibin (range 55.3–72.3 U/1) during the follicular phase until day –2 after which an increase to a midcycle peak of 139± 10.6 U/1 was observed. No correlation was observed between inhibin and B-FSH during the follicular phase. A second increase in the concentration of inhibin was seen during the luteal phase; peak levels occurred by day 6 (311 ±25.8 U/1), remained elevated until day 12, and were negatively correlated with B-FSH (r=–0.53, P<0001). No correlation was observed between oestradiol and inhibin or B-FSH during the luteal phase. We conclude that (1)