玻璃体内注射曲安奈德治疗视网膜中央静脉阻塞引起的黄斑水肿

目的：探讨玻璃体内注射丙酮化曲安奈德用于治疗视网膜中央静脉阻塞（CRVO）引起黄斑水肿的安全性和有效性。方法：在Wisconsin大学和Bascom Palmer眼科研究所．对13例（13只眼）连续的CRVO引起黄斑水肿的患者应用玻璃体内注射丙酮化曲安奈德（4mg）治疗．回顾研究其病历记录。每次玻璃体内注射时应用27G或30G针头通过睫状体平坦部注射。主要结果测量：Snellen视力的变化、黄斑水肿的临床表现、应用光学相干断层扫描仪（OCT）测量中心凹的增厚以及并发症的出现频率。结果：13例患者的平均年龄为67岁（四分位数间距为57—77岁）．注射前症状的平均持续时间为8个月（四分位数间距为4—9个月）。患眼在初诊时的平均视力为20／500．在6个月随诊检查时的平均视力为20／1踟。所有13例患者都完成了6个月的随诊检查。非缺血型CRVO患眼（n=5）的视力有显著的提高．而缺血型CRVO患眼（n=8）没有显著的视力提高。患者没有出现视力下降。初诊时OCT测量的平均中心凹厚度为590μm（视网膜增厚=416μm）。12例患者在1个月随诊检查时OCT测量的平均中心凹厚度为212pm（视网膜增厚=38μm）。13例患者在3个月随诊检查时OCT测量的平均中心凹厚度为193μm（视网膜增厚=19μm）。在3和6个月随诊检查之间．4例患者的黄斑水肿复发．其中3例患者再次接受了曲安奈德的注射。这3例患者中的2例经过再次治疗视力提高。在6个月随诊检查时．13例患者OCT测量的平均中心凹厚度为281μm（视网膜增厚=107μm）。没有发生视网膜脱离或眼内炎等并发症。1例患者出现了眼压的升高．应用2种房水生成抑制剂治疗得以控制。结论：在部分CRVO引起黄斑水肿的患者中．玻璃体内注射曲安奈德可能是一种有效的治疗方法。与缺血型CRVO患者相比．非缺血型CRVO患者可以获得更令人满意的效果。部分患者可能需要重复治疗。在本组患者中未发现严重的并发症。     

Idiopathic hypercalciuria of childhood: 4- to 11-year outcome

Apart from a minority with urolithiasis, the majority of children diagnosed with idiopathic hypercalciuria present with macro- or microhematuria, abdominal or back pain, or voiding symptoms. With dietary and pharmacological interventions, most such children become asymptomatic and are lost to follow-up, hence their long-term outcome is unclear. In the present study, we evaluated the status of 14 males and 19 females aged 8-17 years (mean 11.9 years, median 11.2 years) 4-11 years (mean 6.9 years, median 6.5 years) after the initial diagnosis of idiopathic hypercalciuria not associated with urolithiasis. A questionnaire was answered and two random urine samples provided 3-4 weeks apart were analyzed for calcium (Ca), sodium (Na), potassium (K), and creatinine (Cr). Urine Ca/Cr ratio > or =20.21 (mg/mg) was defined as hypercalciuria. At the time of the study none were under follow-up, although 7 children were still exhibiting voiding symptoms. No child developed clinical urolithiasis. Based on the first urine specimen, 16 of the 33 (48.4%) were hypercalciuric. Their 2nd urinalysis showed persistent hypercalciuria in 8 and normocalciuria in 8. Urine Na/K ratio (mEq/mEq) decreased in the latter 8 from 5.08+/-2.67 to 3.03+/-2.23 (P<0.05). Of the 17 initially normocalciuric children, 5 did not submit a 2nd specimen, 11 remained normocalciuric, and 1 became hypercalciuric with an increase in urine Na/K ratio. Twenty-three children (all 8 persistently and 9 intermittently hypercalciuric plus 6 normocalciuric) were studied by ultrasonography. Only in 1 asymptomatic persistently hypercalciuric child was a single small renal calcification noted. Introduction of a low-Na/high-K diet in 7 persistently hypercalciuric children resulted in a decrease in UNa/K ratio from 7.34+/-2.15 to 4.14+/-3.09 (P<0.01) and UCa/Cr ratio from 0.25+/-0.04 to 0.13+/-0.03 (P<0.01). We conclude that even though over time most hypercalciuric children become asymptomatic, many remain hypercalciuric. Further follow-up is required to ascertain whether these children are at risk of developing kidney stones. If they are at risk then long-term compliance with a low-Na/high-K diet might be beneficial, as it can normalize calciuria in the majority of these children.     

Sieving coefficient inaccuracies during hemodiafiltration in patients with hyperbilirubinemia

Hemodiafiltration has assumed an important role in the supportive therapy of critically ill patients. The viability of the filter used for hemodiafiltration can be monitored by estimating the sieving coefficient of small molecules such as creatinine and/or urea. We report on three patients with severe hyperbilirubinemia whose creatinine sieving coefficient was spuriously elevated as a result of discordance in the accuracy of creatinine measurement in plasma and ultrafiltrate respectively. This discordance was a consequence of lack of bilirubin clearance during hemodiafiltration. As a result, while the plasma creatinine determination by the kinetic Jaffe method was negatively influenced by the hyperbilirubinemia, the ultrafiltrate creatinine was not. This report is the first to document the lack of bilirubin clearance during hemodiafiltration and its impact on the calculation of sieving coefficient based on creatinine. The use of urea as the solute for determining the sieving coefficient allows for an accurate estimate and provides a valid means of monitoring this parameter in the setting of hyperbilirubinemia. Received: 18 April 2000 / Revised: 16 June 2000 / Accepted: 20 June 2000     

The prevention and treatment of perinatal sepsis in a neonatal intensive care unit

We report our experience with 345 premature infants weighing less than 1,500 g admitted to the neonatal intensive care unit during 1990–1993. The improved survival of the very-low-birth-weight patients was related mainly to the routine use of surfactant in the treatment of respiratory distress. In addition, as a result of several preventive precautions, early diagnosis, and appropriate antimicrobial therapy, a decrease in neonatal sepsis was observed. The decrease in the ratio between the number of septic episodes to the number of septic patients is another indication of the efficacy of our current preventive and therapeutic protocols. Correspondence to: S. Katz     

The Safety of Simultaneous Arterial and Coronary Sinus Perfusion: Experimental Background and Initial Clinical Results

Concern over myocardial damage from simultaneous arterial (antegrade) and coronary sinus (retrograde) perfusion has led to alternating between these delivery routes to maximize their individual benefits. Based upon predominant retrograde drainage via Thebesian veins, this study: (1) confirms experimentally the safety of simultaneous arterial and coronary sinus perfusion; and (2) reports initial clinical application of this combined strategy in 155 consecutive patients. Experimental: Five mini-pigs (25 to 30 kg) underwent 1 hour of aortic clamping with simultaneous aortic and coronary sinus perfusion at 200 mUmin with normal blood (37°C) before and after 30 minutes of perfusion with either warm (37°C) or cold (4°C) blood cardioplegia. Coronary sinus pressure was always less than 30 mmHg. There was no right or left ventricular edema, lactate production, or lipid peroxidation as transmyocardial and myocardial conjugated dienes were unaltered, and postbypass recovered left ventricular end-systolic elastance (conductance catheter) and preload recruitable stroke work Index 101%± 3% and 109%± 90%, respectively. Clinical: Simultaneous arteriaVcoronary sinus perfusion was used in 155 consecutive high risk patients (New York Heart Association Class III to IV) undergoing isolated coronary artery bypass grafting (CABG) (n = 109) and CABG + valve replacementlrepair or aneurysm (n = 46). Included were 16 patients in cardiogenic shock and 24 undergoing reoperation. Mean aortic clamping time averaged 90 ± 4 minutes (range 30 to 207), with 3.5 ± 0.1 grafts per patient; all anastomoses were performed with the aorta clamped. Cold intermittent blood cardioplegia was used for distal anastomoses and valve implantationhepair in 123 patients, and warm continuous blood cardioplegia was used in 32 patients. Following a warm cardioplegic reperfusate, all patients received warm non-cardioplegic blood perfusion simultaneously via grafts and coronary sinus. Coronary sinus pressure was always less than 40 mmHg. Of 18 patients requiring postoperative mechanical circulatory support (IABP), 16 had IABP placed preoperatively for cardiogenic shock. There were three postoperative myocardial infarctions (2%), and six patients died (3.9% mortality). Conclusion: These experimental and clinical findings overcome perceived concerns about myocardial damage from simultaneous arterial and coronary sinus perfusion, and suggest this approach may add to the armamentarium of cardioprotective strategies. (J Card Surg 1994;9:15–25)     

Tolerance and Conditioning to Neuro-Muscular Electrical Stimulation Within and Between Sessions and Gender

This study was conducted to determine: 1) If healthy subjects can be conditioned to tolerate clinically useful electrically induced muscle contraction; and 2) If there is a gender difference in response to such conditioning. Healthy volunteers (10 males, 11 females, mean age of 27.6 ± 5.8 yrs) were tested during each of 6 testing sessions. Maximal voluntary isometric contractions (MVIC) of the right quadriceps femoris (RQF) recorded by a computerized dynamometer. Electrical stimulation delivered through two surface electrodes and stimulation amplitude increased until the subject indicated to stop. After a 1 min rest the amplitude increased again to the same phase charge level, and the electrically induced contraction (EIC) was recorded by the dynamometer. Measurements of stimulation amplitude were repeated in each of 10 stimulation bouts per session. Measurements of EIC were repeated in session six. Statistical analyses included Multivariate ANOVAs, and Newman-Kuel’s post-hoc tests (p < 0.01). Mean values of phase charge increased from session 1 to 6 for all subjects. Males tolerated significantly higher phase charge. The mean %MVIC torque generated by female subjects was initially only 11.2 ± 21.6% but reached 42.9 ± 25.4% at the end of the 6th session. Males’ %MVIC torque values were significantly higher reaching 49.0 ± 41.6% and 73.5 ± 18.7% in the first and last trials respectively. Using the criterion that electrically induced contractions must be at least 25% of MVIC to be considered clinically useful, 36% of females were below this threshold at the end of the last session. In contrast, all males exceeded the 25% MVIC threshold at the end of the study. Most healthy subjects can be conditioned to electrical stimulation of the quadriceps, but depending on the criteria of therapeutic value and gender, some males and even more females may not reach the desired stimulation goal in 6 sessions. Females may require more conditioning sessions to reach contraction levels of therapeutic benefits. The reason(s) for the confounding factor of gender remains unknown.

Key Points

• Neuromuscular electrical stimulation (NMES) can strengthen skeletal muscles
• Tolerance to NMES improves within 6 sessions
• Conditioning is a key to eliciting stronger contraction and to increasing the number of subjects that can benefit from NMES
• Healthy males can tolerate higher stimulusintensity and higher electrically induced quadriceps femoris contraction.

Key Words: Neuromuscular electrical stimulation, tolerance, conditioning, gender     

Resolution of medullary nephrocalcinosis in children with metabolic bone disorders

Ultrasonographic resolution of nephrocalcinosis (NC) has been reported in children with furosemide-induced NC, but not in other entities. We report the cases of four children with metabolic bone disease, two with hypophosphatasia and two with X-linked hypophosphatemic rickets, in whom we observed resolution of renal calcifications. At the time of ultrasonographic resolution of NC, 3 of the patients were on anticalciuric diuretics, and all 4 had normal urinalysis, serum creatinine and electrolyte profiles, as well as estimated creatinine clearance. In 3 of the children, evidence of mild tubular dysfunction was found. It thus seems that in some children with bone and mineral disorders who develop NC, ultrasonographic resolution of the renal calcifications can be seen; however, mild tubular dysfunction may remain and require follow-up. Further studies are suggested to explore the possible role of anticalciuric diuretics in promoting the resolution of NC.