Regeneration-blocked mdx muscle: in vivo model for testing treatments.

We have refined the mdx mouse as a clinical model for Duchenne dystrophy. Our power estimates, primary measures, regular sacrifice intervals, and quality checks constitute a high-speed, low-cost system for preclinically testing therapies designed to slow muscle destruction in Duchenne dystrophy. Irradiated (18 Gy) and contralateral shielded anterior tibial muscles were studied in 21-day-old mdx and normal mice at the time of irradiation and 4, 8, 12, 16, and 20 weeks thereafter. Regeneration-blocked mdx (irradiated) muscle expressed muscular dystrophy as progressive wasting after a brief (4 week) period of growth. Regeneration-blocked normal muscle showed stunted growth but neither progressive wasting nor microscopic pathological changes.

Increased expression of proliferating cell nuclear antigen in liver allograft rejection.

Detection of proliferating cell nuclear antigen is useful for the study of proliferative activity of neoplastic and non-neoplastic lymphoid, parenchymal, and mesenchymal cells. Allograft rejection is associated with the recruitment of circulating cells and their proliferation in the graft. The intrahepatic expression of proliferating cell nuclear antigen on paraffin-embedded liver biopsy specimens (n = 110 from 32 patients) was examined by an avidin-biotin peroxidase method using a monoclonal antibody to proliferating cell nuclear antigen. The percentage of positive nuclei was determined in hepatocytes, biliary epithelium, and lymphocytes. There were four histologic groups: 1, moderate-to-severe rejection (n = 19); 2, mild rejection (n = 28); 3, nonspecific inflammation (n = 45); and 4, donor livers (n = 18). The percentage of positive nuclei was higher in group 1 compared to group 2 (hepatocytes p = 0.01; biliary epithelium p = 0.0007; lymphocytes p = 0.0001), to group 3 (hepatocytes p = 0.0002; biliary epithelium p = 0.0001; lymphocytes p = 0.0001), and to group 4 (for all three locations p < 0.0001). When group 2 was compared to group 3 the results were significant for biliary epithelium (p = 0.0001) and lymphocytes (p = 0.0001), but not for hepatocytes (p = 0.07). We conclude that proliferating cell nuclear antigen expression, especially in lymphocytes, correlates with the severity of histologic rejection. Proliferating cell nuclear antigen expression may be useful in predicting the progression and response to different antirejection therapies.

A simplified gonadotrophin-releasing hormone test for precocious puberty.

BACKGROUND AND OBJECTIVE: The gonadotrophin-releasing hormone (GnRH) test is important for the evaluation of children with disorders of puberty. Traditionally, the test determines the peak LH and the peak FSH responses from 5 to 8 blood samples, which makes it cumbersome and costly. We suspected that the test could be simplified to require fewer hormonal measurements. DESIGN: A retrospective clinical study. PATIENTS: Subjects were 44 girls and 7 boys with signs of precocious puberty, of whom 39 were diagnosed as definite central precocious puberty. Fifty-five diagnostic tests and 39 tests for suppression during GnRH-analogue treatment were reviewed. MEASUREMENTS: LH and FSH were measured in serum samples obtained during a standard GnRH test. PARAMETERS: LH and FSH responses and the LH:FSH ratio at 30, 45 and 60 minutes, and the respective peak levels. For each parameter, the sensitivities and specificities were estimated and the receiver operating characteristic curve was constructed. RESULTS: The receiver operating characteristic curves for the LH responses at 30, 45 and 60 minutes and peak, were similar and showed high specificities and sensitivities for the diagnosis of central precocious puberty. A single LH cut-off (15 IU/I) had diagnostic sensitivity > 90% and specificity > 80% for LH concentrations at 30, 45 or 60 minutes and peak, and sensitivity > 90% to detect suppression. Calculations of the LH:FSH ratio did not improve the diagnostic accuracy of the GnRH test achieved by LH alone. CONCLUSIONS: A single LH determination 30 minutes after GnRH administration is as useful as the peak LH; FSH measurements are unnecessary for the differential diagnosis of central precocious puberty. We propose that for the diagnosis of central precocious puberty and for treatment monitoring, the GnRH test to be simplified to LH measurement in a single blood sample at 30 minutes.

Occult sleep-disordered breathing in stable congestive heart failure.

OBJECTIVE: To determine the prevalence and effect of sleep-disordered breathing in ambulatory patients with stable, optimally treated congestive heart failure. DESIGN: A prospective, longitudinal study. SETTING: Referral sleep laboratory of a Department of Veterans Affairs medical center. PATIENTS: 42 of the 48 eligible patients with stable congestive heart failure and left ventricular systolic dysfunction (left ventricular ejection fraction < or = 45%). MEASUREMENTS: After an adaptation night, polysomnography and Holter monitoring were done in the sleep laboratory. Arterial blood gases and pH were measured, and cardiac radionuclide ventriculography and pulmonary, renal, and thyroid function tests were done. RESULTS: Patients were divided into two groups. Group I (n = 23) had an hourly rate of apnea and hypopnea (apnea-hypopnea index) of 20 episodes per hour or less; group II (n = 19 [45%; CI, 30% to 60%]) had an index of more than 20 episodes per hour. In group II, the index varied from 26.5 to 82.2 episodes per hour (mean +/- SD, 44 +/- 13 episodes per hour; CI, 38 to 51 episodes per hour). Group II had significantly more arousals (24 +/- 12 compared with 3 +/- 3 in group I) that were directly attributable to episodes of apnea and hypopnea, longer periods of time with an arterial oxyhemoglobin saturation of less than 90% (23% +/- 24% of total sleep time compared with 2% +/- 4%), lower arterial oxyhemoglobin saturation during sleep (74% +/- 13% compared with 87% +/- 4%), lower left ventricular ejection fraction (22% +/- 9% compared with 30% +/- 10%), and a significantly increased number of episodes of nocturnal ventricular arrhythmias. Multiple regression analyses showed that left ventricular systolic dysfunction was an independent risk factor for sleep apnea in patients with congestive heart failure. CONCLUSIONS: The prevalence of severe occult sleep-disordered breathing is high in ambulatory patients with stable, optimally treated chronic congestive heart failure. The breathing episodes are associated with severe nocturnal arterial blood oxyhemoglobin desaturation and excessive arousals. Severe untreated sleep-disordered breathing may adversely affect left ventricular function, resulting in a vicious cycle that could contribute to death in patients with congestive heart failure. Prospective, longitudinal studies on survival are needed.

Radiation inhibition of mdx mouse muscle regeneration: dose and age factors.

A single hind limb was irradiated with 12, 18, 24, or 30 Gy in mdx and C57 mice aged 12, 21, or 42 days to determine regeneration inhibition dose-response curves in different aged dystrophic mice and to characterize radiation side-effects in normal mice. The anterior tibial muscle mass (8 weeks postirradiation) and percent central nucleated (i.e., regenerated) muscle fibers were measures of regeneration inhibition. Twenty-one-day-old mdx mice irradiated with 18 Gy had complete inhibition of muscle regeneration, but 30 Gy only partially blocked regeneration in mdx mice irradiated at 12 and 42 days in age. In working to produce a clinically relevant model for Duchenne dystrophy, it is crucial to regard mouse age as a major factor in determining radiation effects on mdx muscle regeneration.

The relevance of ligament tears or perforations in the diagnosis of wrist pain: an arthrographic study.

This study was designed to assess the clinical significance of arthrographic abnormalities in the ligaments of a painful wrist. This was accomplished by means of comparison arthrography of the asymptomatic wrist. Fifty-six consecutive patients with unilateral wrist pain underwent selective bilateral arthrography to assess interruptions of continuity of the triangular fibrocartilage, lunotriquetral, and scapholunate ligaments. The prevalence of bilaterally symmetric lesions was high. In patients with ligament defects in the symptomatic wrist, 88% of defects near the radial attachment of the triangular fibrocartilage, 59% of lunotriquetral defects, and 57% of scapholunate defects were bilateral. Furthermore, physical examination was not predictive of specific ligament defects. This study raises questions concerning the relevance of interrupted ligaments in the diagnosis of wrist pain.

Comparative evaluation of three diphosphonates: in vitro adsorption (C- 14 labeled) and in vivo osteogenic uptake (Tc-99m complexed).

We have investigated the in vitro adsorption of three C-14-labeled diphosphonates on calcium phosphate. The three are 1-hydroxy[1-14C]ethylidene diphosphonate (C-14 HEDP), [14C]methylenediphosphonate (C-14 MDP), and hydroxy[14C]methylenediphosphonate (C-14 HMDP). All three adsorbed significantly more, per mole of calcium, on amorphous calcium phosphate than on crystalline hydroxyapatite. Among the three diphosphonates, C-14 HMDP adsorbed--on both amorphous and crystalline calcium phosphate--to a greater degree than did the other two bone-seeking agents. Moreover, when HMDP was complexed with Sn(II) and Tc-99m, it produced a significantly higher uptake of Tc-99m, per mg of calcium, in an isolated in vivo site of osteogenesis. The mechanisms of adsorption are discussed relative to the hydroxyl group on the diphosphonate, to the solubility of the calcium salts to the diphosphonates, and to the form of the calcium phosphate. These studies form a working rationale for the clinically observed high contrast obtained with Tc-99m HMDP between normal bone and soft tissue, and between normal and abnormal bone.

An acne grading method using photographic standards.

A grading system for following the clinical course of acne was devised in which overall severity of acne is evaluated on a zero to eight scale anchored to photographic standards that illustrate grades 0, 2, 4, 6, and 8. Experience with use of this system in large-scale clinical trials has shown it to be useful and reliable. Photographs taken at each visit create a permanent and regradable record of each subject's clinical status throughout the course of treatment.