CRF IN THE DIFFERENTIAL DIAGNOSIS OF CUSHING''S SYNDROME: A COMPARISON WITH THE DEXAMETHASONE SUPPRESSION TEST

Accurate differential diagnosis of the precise cause of Cushing's syndrome can be difficult, and conventional tests such as those based on the use of dexamethasone may be misleading. We have therefore studied the cortisol and ACTH responses to ovine corticotrophin-releasing factor (CRF-41) in 28 consecutive patients with Cushing's syndrome, and compared the diagnostic value of this test with that of the high-dose dexamethasone suppression test (8 mg/day for 48 h). Of 20 patients with confirmed Cushing's disease (pituitary-dependent Cushing's syndrome), only 16 (80%) showed the expected 50% or more suppression of serum cortisol following high-dose dexamethasone administration. Four patients each with adrenal adenomas and three patients with the ectopic ACTH syndrome failed to suppress, while a child with probable Cushing's disease showed a variable response depending on the dose used. Following CRF stimulation, 15 out of the 20 patients (75%) with Cushing's disease showed an excessive rise in serum cortisol, outside the normal range, while in five the response to CRF-41 was normal on at least one occasion. None of the patients with adrenal adenomas or the ectopic ACTH syndrome showed a cortisol response to CRF. Thus, either test on its own may be misleading in differentiating Cushing's disease from other causes of the syndrome. Every patient with Cushing's disease, however, showed either suppression in response to high-dose dexamethasone or an excessive cortisol response to CRF testing. It appears, therefore, that the combination of the high-dose dexamethasone and the CRF test, with measurement of serum cortisol, is superior to either test alone in the differential diagnosis of Cushing's syndrome.     

THE HERITABILITY OF ALCOHOL ABUSE AND DEPENDENCE: A META-ANALYSIS OF BEHAVIOR GENETIC RESEARCH

A meta-analysis was performed on 50 family, twin, and adoption studies in which problem drinking and alcohol dependence served as the primary criterion measure. The results showed that far from being an established “fact,” the genetic foundations of alcohol misuse are modest and heterogeneous. A weighted mean ? effect size of 0.12 (95% Confidence Interval=0.11–0.12) was obtained for the total sample of 72 effect sizes. Four potential moderator variables (proband gender, sample nationality, pattern severity, year of publication) were examined with outcomes confirming that the heritability of alcohol misuse is stronger in males and in studies employing more severe definitions of abuse (alcoholism, alcohol dependence). When the effect size measure was restricted to studies using male subjects with more severe diagnoses of alcohol misuse, the unweighted mean ? effect size was only 0.18 (95% Confidence Interval=0.15–0.21), with an even smaller weighted mean ? effect size of 0.15 (95% Confidence Interval=0.12–0.18); results which indicate an upper limit of 30–36% for the heritability of alcohol misuse.     

广西40株犬种布鲁氏菌与标准株药敏试验的比较

本文介绍广西40株犬种布氏菌,1株猪Ⅲ型菌和6株标准布氏菌株对17种常用抗菌素的药物敏感试验结果,以氯霉素、强力霉素、四环素、庆大霉素、红霉素、卡那霉素和链霉素的抑菌效果最好。抑菌效果最差是头孢霉素、苯唑霉素、氨基苄青霉素、青霉素和磺胺异恶唑。对犬种布氏菌抑制效果最好的四种抗菌素组成六种组合,以四环素与强力霉素和链霉素与四环素等两种组合的协同效果最好。     

原头节抗原IFAT和IEST诊断人体包虫病的比较研究

以冰冻保存的绵羊棘球蚴内原头节为抗原作间接荧光抗体试验(IFAT)和间接免疫酶染色试验(IEST),检测对包虫病人、非包虫病人及键康人的敏感性、特异性及交叉反应性,并与间接血凝试验相比较(IHAT)。结果表明IFAT的敏感性和特异性分别为90.36％和97.67％;IEST的敏感性和特异性分别为96.55％和100.0％;两种方法均高于IHAT的敏感性(85.54％)和特异性(95.35％)。三种方法对血吸虫感染者和癌症病人血清均无交叉反应,但对囊虫病人的交叉反应率为IFAT(51.35％)>IHAT(37.84％)>IEST(21.62％)。以原头节为抗原IEST诊断人体包虫病敏感性高、特异性强,适用范围广,不需特殊设备,具有现场应用价值。     

Köln Haemoglobinopathy: FURTHER DATA AND A COMPARISON WITH OTHER HEREDITARY HEINZ BODY ANAEMIAS

Five patients with haemolytic anaemia from one family were studied; three had splenomegaly and one who had been splenectomized had numerous inclusions in his fresh red cells. An abnormal haemoglobin was found by electrophoresis. This was isolated and identified as α₂β₂ 98 Valine → Methionine, i.e. Haemoglobin Köln.
Abnormal red cell GSH and methaemoglobin values were found in fresh and incubated blood. The presence of a heat-labile haemoglobin fraction and the formation of inclusion bodies in red cells incubated in vitro was confirmed. Red-cell morphology and the benefit of splenectomy are discussed.
The findings in patients with Haemoglobin Köln are compared with those reported in other hereditary Heinz-body anaemias. It appears that at present Köln haemoglobinopathy is the commonest member of this group of disorders.     

PCR 与 DIFA 检测沙眼衣原体的比较研究

用所建立的沙眼衣原体质粒引物聚合酶链反应技术（ＰＣＲ）检测１１６例泌尿生殖道沙眼衣原体，并与直接免疫荧光法（ＤＩＦＡ）进行比较。结果ＰＣＲ阳性３８例，ＤＩＦＡ阳性的３２例中有３１例ＰＣＲ阳性。ＰＣＲ敏感性为９６．９％，特异性为９１．７％。ＰＣＲ阳性者于治疗结束１～２周后复诊２１例，其中４例ＰＣＲ仍然阳性。结果显示，ＰＣＲ可快速、敏感、特异地检测泌尿生殖道沙眼衣原体ＤＮＡ，然而对治疗后短期内复诊患者，似乎不宜仅以ＰＣＲ阳性结果作为重复治疗的依据。     

A COMPARISON OF CALCIUM PENTAGASTRIN AND TRH TESTS IN SCREENING FOR MEDULLARY CARCINOMA OF THE THYROID IN MEN IIA

Intravenous injections of calcium gluconate and pentagastrin (CPG) or TRH were compared as secretagogues for calcitonin (CT) in screening for medullary thyroid carcinoma (MTC) in multiple endocrine neoplasia type IIA (MEN IIA). Administration of CPG resulted in a prompt increase in plasma CT in all five patients with MTC studied, one of whom had a normal baseline value (peak 412-371,000 ng/l, 636-4847% above basal). TRH produced a rise in plasma CT levels only in MTC patients with elevated basal values; the magnitude of increase was less than that observed with CPG (peak 168-17,200 ng/l, 113-180% above basal). CT levels did not rise above 300 ng/l with either test in four unaffected first-degree relatives of MEN IIA patients, three subjects with sporadic unilateral phaeochromocytomas and five controls with essential hypertension. CPG remains the CT secretagogue of choice in screening for MTC in MEN II A.     

THE CHOLINERGIC APPROACH FOR THE TREATMENT OF VASCULAR DEMENTIA: EVIDENCE FROM PRE-CLINICAL AND CLINICAL STUDIES

The involvement of an impaired cholinergic neurotransmission in the pathophysiology of cognitive impairment occurring in vascular dementia (VaD), as well as the possibility of treating it by stimulating cholinergic neurotransmission was reviewed. Pre-clinical data suggest that similarly as documented in dementia disorders of neurodegenerative origin, a cholinergic deficit is involved in the pathophysiology of cognitive impairment of vascular origin. In the past, clinical trials have evaluated cholinergic precursors such as lecithin, citicoline and choline alphoscerate. More recent investigations have assessed acetylcholinesterase (AChE) and cholinesterase (ChE) inhibitors such as donepezil, rivastigmine and galantamine.

In general, treatment with citicoline, choline alphoscerate, as well as with AChE and ChE inhibitors induced favourable effects on cognitive function in dementia disorders of vascular origin. These positive results should be regarded with caution due to the small number of patients included in controlled clinical trials using cholinergic precursors and to the limited number and sample size of trials with AChE and ChE inhibitors. Among compounds investigated, choline alphoscerate was well tolerated, improved cognitive function in VaD patients to a better extent than citicoline and to similar or better extent than other more recently developed drugs. This particular profile would justify reconsideration of the compound in larger controlled clinical trials for the treatment of cognitive dysfunction associated with dementia disorders of vascular origin.     

HIV AND HCV COINFECTION: PREVALENCE,ASSOCIATED FACTORS AND GENOTYPE CHARACTERIZATION IN THE MIDWEST REGION OF BRAZIL

A cross-sectional study on prevalence, associated factors and genotype distribution of HCV infection was conducted among 848 HIV-infected patients recruited at reference centers in the Midwest Region of Brazil. The prevalence rate of HIV-HCV coinfection was 6.9% (95% CI: 5.2 to 8.6). In multivariable analysis, increasing age, use of illicit drugs (injection and non-injection), a history of blood transfusion before 1994, and the absence of a steady partnership were significant independent associated factors for HIV-HCV coinfection. The phylogenetic analysis based on the NS5B region revealed the presence of two major circulating genotypes of HCV: genotypes 1 (58.3%) and 3 (41.7%). The prevalence of HIV-HCV coinfection was lower than those reported in studies conducted with HIV-infected patients in different regions of Brazil, due to the fact that illicit drug use is not a frequent mode of HIV transmission in this region of Brazil. Serologic screening of HIV-patients for HCV before initiating antiretroviral treatment, a comprehensive identification of associated factors, and the implementation of effective harm reduction programs are highly recommended to provide useful information for treatment and to prevent HCV coinfection in these patients.     

FINE ADJUSTMENT OF THYROXINE REPLACEMENT DOSAGE: COMPARISON OF THE THYROTROPHIN RELEASING HORMONE TEST USING A SENSITIVE THYROTROPHIN ASSAY WITH MEASUREMENT OF FREE THYROID HORMONES AND CLINICAL ASSESSMENT

Thyroxine replacement therapy for 21 adult patients with primary hypothyroidism was adjusted to the dosage at which each patient had a normal thyrotrophin (TSH) response to thyrotrophin releasing hormone (TRH). Clinical assessment and measurement of TSH (by sensitive immunoradiometric assay), free thyroxine (FT4) and free tri-iodothyronine (FT3) were made at this dosage and at higher and lower doses of thyroxine. Clinical observations, FT3 and FT4 assays were relatively insensitive to small alterations of thyroxine dosage, in contrast to which basal TSH measurements correlated well with TRH responsiveness and were sensitive to fine adjustments of thyroxine dosage.