The spermatozoal volume as indicative of the plasma membrane integrity (modification of the hypoosmotic swelling test). I. Methods

Summary. The aim of the present study was to establish a more differentiating indicator of plasma membrane integrity of spermatozoa than the classic version of the hypoosmotic swelling test according to Jeyendraan. Spermatozoa were prepared by density gradient centrifugation (90% Percoll) to select 'fertilization competent' spermatozoa only. After a second washing procedure sufficiently pure sperm cell suspensions were obtained. The volume distributions of these sperm cells were measured with a Coulter Counter at 25 °C after adaptation in 300 mosmolar NaCl solution resp. 150 mosmolar NaCl solution for 5 min. These volume distributions showed significantly different patterns for the isotonic and hypotonic stress situation in the simple salt solution. Moreover, the comparison of the response to hypoosmotic stress showed more than four reproducible characteristic patterns, promising well differentiated results for different sperm populations. The new method for the detection of hypoosmotic swelling effect might be a real and valuable functional parameter.     

Validity and ethics of penile circumference measures of sexual arousal: A reply to McConaghy

McConaghy (1989) argued that the validity of penile circumference responses (PCRs) is at best unestablished and that penile volume responses (PVRs) have been demonstrated to be clearly superior indices of sexual arousal and orientation. In his critique, McConaghy stated that (i) penile erection has been incorrectly identified with sexual arousal, (ii) that PCRs have not been shown to accurately discriminate between divergent patterns of sexual arousal (including paraphilias), (iii) that the methodologies used to compare the two types of transducers are inappropriate, and (iv) that PCRs should not be used for diagnostic and treatment decisions. In this paper, McConaghy's criticisms are reviewed in the context of the existing literature on the subject. Although PCRs and PVRs involve different methodologies, they generally yield results that bear more similarities than differences. Furthermore, there is an extensive and growing literature on the use of PCR measures with various paraphilias. Several of McConaghy's arguments should be considered tentative while others are clearly unsubstantiated. Most of McConaghy's concerns over the validity and uses of PCR measures are empirical questions. Suggestions for future research are offered.     

维汉族BPH患者前列腺形态与尿流动力学的相关性

目的 探讨维汉民族前列腺增生患前列腺的体积、症状积分和膀胱排尿症状的相关性。方法 对71例住院手术的维汉不同民族前列腺增生症(BPH)患进行国际前列腺症状评分(BPSS)，生活质量评分(L)，前列腺体积(V)，重量(M)，患年龄(age)，尿流动力学指标的直线相关分析。结果 40例汉族及31例维族BPH患的前列腺体积与膀胱颈压，膀胱颈压与膀胱顺应性，最大尿流率与膀胱顺应性均呈正相关。结论 最大尿流率、前列腺体积、膀胱顺应性、膀胱颈压四个参数不但能了解膀胱排尿功能和形态改变，也可做为临床上手术切除增生前列腺组织，解除梗阻，缓解症状，评价治疗效果的指标。     

Evaluation of local cerebral glucose utilization and the permeability of the blood-brain barrier in the genetically epilepsy-prone rat

Summary The genetically epileptic-prone rat (GEPR) is a valuable model for the study of gene-linked abnormalities involved in epilepsy. In comparison with normal Sprague-Dawley controls, we found, in GEPRs, a marked depression in local cerebral glucose utilization, widespread throughout the brain. This depression was accompanied by a significant increase of blood-brain barrier permeability and a reduction in regional blood volume. Finally GEPRs showed lower plasma levels of total triiodothyronine than normal controls. One can speculate that alterations in cerebral metabolism and microvascular regulation and thyroid hormone imbalance may be gene-linked factors involved in seizure susceptibility.     

Effects of Clodronate on Cortical and Trabecular Bone in Ovariectomized Rats on a Low Calcium Diet

The aim of this study was to evaluate the contribution of a low calcium diet to the cortical and trabecular osteoporosis seen in ovariectomized rats after 7 weeks on a low calcium diet and to investigate the effects of the bisphosphonate clodronate on this development of osteoporosis. Thirty-six mature, female Wistar rats were randomized into four groups: Ovx−B (bisphosphonate) and Ovx−C (control) were ovariectomized, and Sham−Ca (low calcium) and Sham+Ca (normal calcium) were sham operated. The first three groups were fed a low calcium diet (0.01%) and Sham+Ca normal rat chow (Ca 1.1%). The Ovx−B received 10 mg/kg s.c. clodronate daily for nine weeks, and Ovx−C, Sham−Ca, and Sham+Ca received the same volumes of saline. Bone mineral turnover measured as ⁸⁵Sr-uptake was increased in all low calcium groups compared to Sham+Ca. The Sham+Ca femora had higher dry weight and ash weight than the other groups, and Ovx−C had higher dry weight compared with Ovx−B and Sham−Ca. Calcium content was lower in both Ovx groups compared to both Sham groups. Magnesium was lower in all groups compared to Sham+Ca and higher in Ovx−B compared with Ovx−C. In the femoral shaft, Sham+Ca had significantly higher ultimate bending moment, energy absorption, and deflection compared to the other three groups. Ultimate bending moment was higher in Sham−Ca than in Ovx−C. Stiffness was increased in both Sham+Ca and Ovx−B compared to Ovx−C. The maximum stress in the femoral midshaft was higher in Sham+Ca than in the other groups, and higher in Ovx−B than in Ovx−C. Histomorphometry showed increased medullary area in all low calcium groups compared to Sham+Ca and larger cortical area in Sham+Ca and Ovx−B compared to Ovx−C. Compared to Sham+Ca the trabecular bone volume was decreased to 30% in Sham−Ca and to 9% in Ovx−C, but was unchanged in Ovx−B. The low calcium diet generally increased bone mineral turnover and reduced the tibial bone volume. Femoral changes led to a reduction of cortical fracture strength and maximal stress. Ovariectomy in addition to a low calcium diet reduced femoral strength even more. Daily injections of clodronate to ovariectomized rats on a low calcium diet increased femoral shaft stiffness and maximum stress, and clodronate preserved both trabecular and cortical tibial bone volume completely. Received: 11 June 1996 / Accepted: 5 March 1997     

Fluorine-18 fluorodeoxyglucose positron emission tomography and iodine-131 whole-body scintigraphy in the follow-up of differentiated thyroid cancer

Metastases of differentiated thyroid cancer may show different uptake patterns for fluorine-18 fluorodeoxyglucose and [¹³¹I]NaI. FDG positron emission tomography (PET), iodine-131 whole-body scintigraphy (¹³¹I WBS) and magnetic resonance imaging were performed in 58 unselected patients, and spiral computed tomography (CT) of the lung in 25 patients. Thirty-eight patients presented with papillary carcinomas, 15 patients with follicular carcinomas and five patients with variants of follicular carcinoma. Primary tumour stage (pT) was pT1 in 3, pT2 in 19, pT3 in 11 and pT4 in 25 cases. For the detection of metastases, FDG PET was found to have a sensitivity of 50%, ¹³¹I WBS a sensitivity of 61%, and the two methods combined a sensitivity of 86%. When FDG PET was limited to patients with elevated thyroglobulin (Tg) levels and negative ¹³¹I WBS, the sensitivity of this algorithm was 82%. Of the 21 patients with lymph node metastases, seven presented with FDG uptake but no iodine uptake. In four of them, a second FDG hot spot appeared in a lymph node metastasis of normal size. Five of the seven patients underwent surgery. None of the eight patients with pulmonary metastases smaller than 1 cm exhibited FDG uptake, while five of them had iodine uptake. All had positive results on spiral CT. In conclusion, FDG PET cannot be substituted for ¹³¹I WBS. If the Tg level is elevated and ¹³¹I WBS is negative, FDG PET can be used to detect lymph node metastases and complements anatomical imaging. A spiral CT of the lung is useful to exclude pulmonary metastases before planning a dissection of iodine-negative lymph node metastases. Received 2 May and in revised form 8 July 1997     

放射性碘在大鼠甲状腺内的滞留模式及剂量估算

为确定放射性碘在甲状腺内滞留模式，观察甲状腺吸收放射性碘后的生物效应，进而评价其辐射危害。方法利用活体测量方法，直接测量两个不同年龄组大鼠甲状腺内１３１Ⅰ的代谢参数。对测量数据进行处理后得到了大鼠甲状腺内１３１Ⅰ的滞留函数为三指数项函数。结果利用所得三指数项滞留函数的准确方法进行剂量估算，所得的两组动物的甲状腺平均累积吸收剂量分别为７．７Ｇｙ和１１．５Ｇｙ，而一般方法算得的大鼠甲状腺的平均累积吸收剂量比用准确方法高估了６６％～９１％。结论由于准确方法考虑到影响估算甲状腺所受剂量的一些因素，故可相对准确地反映了１３１Ⅰ所致不同年龄大鼠甲状腺的吸收剂量。     

Relation Between Cycle Length, Volume, and Pressure in Type I Atrial Flutter

Assuming that type I atrial flutter is a macroreentrant circuit, its cycle length should vary with the atrial dimensions. In order to test this hypothesis, flutter cycle length was measured while inducing atrial volume and pressure changes by postural and pharmacological means in seven patients undergoing a therapeutic programmed stimulation for type 1 atrial flutter conversion. Right atrial volume was estimated from B-mode echocardiography data. Basal values were compared with those obtained during inspiration, expiration, Valsalva maneuver, negative tilt (head down), and positive tilt (head up) with 0.8–1.6 mg p.o. nitroglycerin. The right atrial size increased slightly from 17.8 to 18.3 cm² (P = 0.04) during the pressure load induced by negative tilt (+ 3 mmHg), with a corresponding lengthening of the flutter cycle length from 228 to 233 msec (P = 0.02). Similarly, pressure unloading of -2 mmHg by positive tilting and nitrates was accompanied by a decrease in right atrial size to 16.6 cm² (P = 0.04), with a corresponding decrease in cycle length from 228 to 219 msec (P = 0.03). Respiratory maneuver yielded similar results with an inspiratory cycle lengthening, expiratory shortening, and further shortening during Valsalva maneuver. These experiments demonstrate a direct relation between cycle length and atrial volume in human type I atrial flutter. They underline the importance of the right heart preload and atrial size for the electrophysiological characteristics of type I atrial flutter. Beside its fundamental interest, this finding is important for the understanding of the mechanism of maintenance and therapeutic responses of this common arrhythmia.     

Cell volume regulation: a review of cerebral adaptive mechanisms and implications for clinical treatment of osmolal disturbances: II

Cerebral cell volume regulatory mechanisms are activated by sustained disturbances in plasma osmolality. Acute hypernatremia causes a predictable shrinkage of brain cells due to the sudden imposition of a plasma-to-cell osmolal gradient. However, during chronic hypernatremia cerebral cell volume is maintained close to the normal range as a result of the accumulation of electrolytes and organic osmolytes including myo-inositol, taurine, glutamine, glycerophosphorylcholine, and betaine. The increased cytosolic level of these molecules is generally accomplished via increased activity of sodium (Na⁺)-dependent cotransport systems. The slow dissipation of these additional osmotically active solutes from the cell during treatment of hypernatremia necessitates gradual correction of this electrolyte abnormality. Acute hyponatremia leads to cerebral cell swelling and severe neurological dysfunction. However, prolonged hyponatremia is associated with significant reductions in brain cell electrolyte and organic osmolyte content so that cerebral cell volume is restored to normal. While acute hyponatremia can be treated with the administration of moderate doses of hypertonic saline in order to control seizure activity, chronic hyponatremia should be corrected slowly in order to prevent subsequent neurological deterioration. If the rate of correction exceeds 0.5 mmol/l per hour, or if the total increment in serum [Na⁺] exceeds 25 mmol/l in the first 48 h of therapy, then there is an increased risk of the development of cerebral demyelinating lesions. Chronic hyperglycemia activates the brain cell volume regulatory adaptations in the same manner as hypernatremia. Therefore, during the treatment of diabetic ketoacidosis, it is imperative to restore normoglycemia gradually in order to prevent the occurrence of cerebral edema. It is possible that excessive administration of electrolyte-free solutions and high doses of insulin may increase the risk of this complication. While there are some data to suggest that brain cell size is disturbed during acute uremia, additional work is necessary to clarify the role of cerebral cell volume regulation during acute and chronic uremia.     

POTASSIUM ACCELERATES URINARY SODIUM EXCRETION DURING SALT LOADING WITHOUT STIMULATING ATRIAL NATRIURETIC POLYPEPTIDE SECRETION

1. Effects of potassium (K) supplementation (100 mEq/day) on urinary sodium (Na) excretion and on the secretion of atrial natriuretic polypeptide (ANP) during salt loading (350 mEq/day) were studied in 12 healthy salt-resistant normotensives under strictly controlled metabolic ward conditions. 2. Urinary volume and Na excretion on the first day of the high salt period (HSP) were significantly greater in the K-supplemented group (KG) than in the control group (CG). 3. There was a significant gain in bodyweight after salt loading in both groups, with a significantly greater gain in CG on the second day of HSP. Haematocrit decreased significantly during salt loading in both groups, the degree of which was significantly greater in CG. 4. Plasma norepinephrine decreased significantly during salt loading in both groups, the degree of which was significantly less in KG than in CG. A significant increase in plasma ANP was observed in CG on and after the second day of HSP, while a significant increase in plasma ANP was observed on the fifth day of HSP in KG. 5. These findings indicate that K supplementation accelerates diuresis and natriuresis, resulting in moderate suppression of volume expansion induced by salt loading and that this accelerated diuresis and natriuresis is not a result of the action of ANP.