Accuracy of 64-section MDCT in the diagnosis of cruciate ligament tears.

AIM: To evaluate the accuracy of non-arthrographic 64-section multidetector computed tomography (CT) in the assessment of cruciate ligament tears. A secondary goal was to determine its accuracy in the diagnosis of additional soft-tissue injuries around the knee. MATERIALS AND METHODS: Forty consecutive outpatients underwent same-day magnetic resonance imaging (MRI) and 64-slice multidetector CT (MDCT) of the knee in this prospective study. MDCT images were independently evaluated for integrity of the anterior (ACL) and posterior cruciate ligaments (PCL), medial and lateral menisci, and medial and lateral collateral ligaments. Recognised secondary signs of ACL tears were also documented. MRI images were subsequently assessed by two radiologists and a consensus reached. RESULTS: The sensitivity of MDCT for ACL tears was 87.5-100%, with a specificity of 100%. The presence of one or more secondary signs of ACL tears on MDCT had a sensitivity of 50-87.5% with a specificity of 100%. The sensitivity of MDCT for PCL tears was 0-25% with a specificity of 100%. The sensitivity for meniscal tears was 9.1-23.1% with a specificity of 96.3-100%. CONCLUSION: 64-section MDCT has very high sensitivity and specificity for ACL tears and, as on MRI, secondary signs, such as buckling of the PCL, are also useful in their diagnosis. MDCT has a low sensitivity for other soft-tissue injuries at the knee; however, its high specificity indicates that apparent PCL, meniscal, and collateral ligament tears can reliably be treated as true-positive findings.

CT colonography and transient bacteraemia: implications for antibiotic prophylaxis.

OBJECTIVES: To determine the prevalence of transient bacteraemia after CT colonography (CTC). METHODS: Blood cultures were obtained at 5, 10 and 15 min after CTC from 100 consecutive consenting patients. Blood samples were cultured in both aerobic and anaerobic media and positive blood culture samples were analysed by a microbiologist. RESULTS: Blood culture samples were positive for growth in sixteen patients. All positive blood culture samples were confirmed skin contaminants. There were no cases of significant bacteraemia. The estimated significant bacteraemia rate as a result of CTC is 0-3.7%, based on 95% confidence intervals around extreme results using Wilson's score method. CONCLUSIONS: American Heart Association and National Institute for Clinical Excellence guidelines advise that antibiotic prophylaxis before lower gastrointestinal endoscopy is not indicated in patients with at risk cardiac lesions (ARCL) as the risk of a transient bacteraemia leading to infective endocarditis is low. These data show that the prevalence of transient bacteraemia after CTC is also low. It follows that patients with ARCL do not require antibiotic prophylaxis before CTC.

PET/CT and breast cancer.

This paper summarises the current status of PET/CT in relation to breast cancer.

Effects of photoperiod and androgen on proopiomelanocortin gene expression in the arcuate nucleus of golden hamsters.

In golden hamsters, seasonal changes in day length act via a pineal-dependent mechanism to regulate feedback and behavioral effects of androgen. Endogenous opiates participate in photoperiodically regulated neuroendocrine functions, but the effects of androgen on expression of the gene encoding POMC, the precursor of beta-endorphin, have been controversial. We used quantitative in situ hybridization to examine regulation of POMC messenger RNA (mRNA) by testosterone and to test the hypothesis that short day lengths act through the pineal gland to amplify POMC mRNA expression. We studied intact hamsters and castrates with or without androgen treatment held in long (14 h of light, 10 h of darkness) or short (5 h of light, 19 h of darkness) days for 10 weeks. POMC gene expression differed with rostral-caudal plane, photoperiod, and surgical treatment (castration and testosterone administration). Testosterone increased the number of silver grains in labeled cells throughout the arcuate nucleus, and short day castrates given androgen consistently had more silver grains per labeled cell than did their long day counterparts. Testosterone exerted an inhibitory effect, however, on the number of POMC mRNA-positive cells, and more POMC mRNA-labeled cells were found in the arcuate nucleus of long than short day castrates treated with testosterone. Photoperiod had no significant influence in castrates not receiving androgen. Testosterone treatment had generally similar effects whether it was begun at the time of castration or 5 weeks later. Pinealectomy blocked the influence of photoperiod on both the mean number of silver grains per labeled cell and the number of labeled cells. The results indicate that day length regulates POMC gene expression when androgen levels are held constant, but that androgen is necessary for photoperiod effects to be expressed.

Photoperiodic regulation of pulsatile luteinizing hormone secretion and adenohypophyseal gene expression in female golden hamsters.

LH concentrations were measured in serum collected at 10-min intervals from chronically ovariectomized female Syrian hamsters that had been maintained for 9 wk in stimulatory (long) or inhibitory (short) photoperiods. Short days reduced the number of detectable LH pulses during both the morning and the afternoon. Most short-day hamsters experienced a gradual afternoon rise in serum LH concentrations; this rise was not composed of multiple pulses. In separate groups of similarly treated hamsters, pituitary LH-beta mRNA abundance was significantly reduced by short-day exposure at both times of day even though serum LH concentrations rose in the afternoon. Estradiol treatment induced an afternoon surge of serum LH in both photoperiods, and eliminated the effect of photoperiod on LH-beta mRNA abundance in the afternoon. Serum prolactin (PRL) concentrations were not consistently influenced by day length in castrated hamsters with or without estrogen treatment, but PRL mRNA abundance was significantly suppressed by short-day exposure in all groups. The results indicate that day length exerts profound steroid-independent effects upon hypophyseal gene expression, and that the regulation of LH-beta mRNA abundance may be due to photoperiodic control of the neural GnRH pulse generator.

Influences of photoperiod on sexual behaviour, neuroendocrine steroid receptors and adenohypophysial hormone secretion and gene expression in female golden hamsters.

Exposure to short daylengths arrests the oestrous cycle, provokes daily gonadotrophin surges and reduces the ability of exogenous oestradiol to trigger behavioural receptivity in golden hamsters. In order to examine neuroendocrine effects of photoperiod which might underlie these responses, ovariectomized hamsters were maintained under long or short photoperiods for 54 days before treatment with cholesterol or various doses of oestradiol-17 beta. Short days reduced the ability of low doses of oestrogen to prime hamsters for the induction of oestrus by progesterone. Upon repetition of oestrogen priming 2 weeks later, photoperiod was without significant influence on the concentrations of nuclear oestrogen receptors or cytosolic progestin receptors in a block of tissue containing the hypothalamus and preoptic area. Oestradiol treatment provoked significant increases in serum concentrations of LH and prolactin in the afternoon, but photoperiod did not alter the positive-feedback efficacy of this gonadal steroid hormone. Adenohypophysial LH-beta subunit and prolactin mRNAs were suppressed by short days in ovariectomized hamsters not treated with oestradiol. Oestradiol decreased expression of the LH-beta subunit gene in both stimulatory and inhibitory photoperiods, but increased prolactin mRNA abundance in both long and short days. Photoperiod therefore exerts pronounced steroid-independent effects on phasic LH and prolactin secretion, but regulation of adenohypophysial abundance of LH-beta subunit and prolactin mRNAs by oestradiol is not markedly influenced by daylength. Photoperiodic regulation of the priming effects of oestradiol on behavioural receptivity may result from modulation of events occurring subsequent to steroid-receptor interactions, or involve changes in receptor populations not detectable by the present methods.

Pituitary hormone gene expression in male golden hamsters: interactions between photoperiod and testosterone.

Abstract Daylength regulates neuroendocrine function in male golden hamsters. Exposure to short days triggers gonadal regression and decreases serum luteinizing hormone (LH), prolactin and testosterone concentrations. Inhibitory photoperiods also amplify the negative feedback actions of androgens upon gonadotropin secretion. To examine whether these changes arise from altered adenohypophyseal gene expression, we measured the abundance of the messenger ribonucleic acids (mRNAs) encoding beta-LH, prolactin and proopiomelanocortin in anterior pituitaries of male golden hamsters which were either left intact, castrated, castrated and implanted with testosterone, or pinealectomized and maintained in either long (14 h light/10 h dark) or short (5 h light/19 h dark) days. Short days caused testicular atrophy in intact male hamsters and reduced serum LH in intact and castrated, testosterone-replaced hamsters. The relative abundance of beta-LH mRNA was suppressed by exposure to short days only in castrated hamsters. Serum prolactin was decreased by short days regardless of circulating testosterone concentrations. Prolactin mRNA abundance was decreased by short days in all pineal-intact groups. Castration reduced proopiomelanocortin mRNA abundance in long days and testosterone replacement reversed this effect. In the presence of testosterone, photoperiod influenced serum LH concentrations without altering hypophyseal abundance of beta-LH mRNA. In contrast, photoperiodic influences on prolactin secretion were correlated with alterations in steady-state mRNA abundance.

Double-blind clinical trials of oral cyclacillin and ampicillin.

A double-blind study was performed to compare the clinical response and the incidence of side effects in 2,581 patients administered ampicillin or cyclacillin for infections of the genitourinary or respiratory tract, infections of the skin and soft tissues, or for otitis media. There was no significant difference in clinical response and bacterial eradication. All side effects, including diarrhea and skin rash, were approximately twice as frequent in patients treated with ampicillin.