Case-control study of the muscular compartments and osseous strength in neurofibromatosis type 1 using peripheral quantitative computed tomography.

Skeletal anomalies are observed in neurofibromatosis type 1 (NF1), but the pathogenesis is unknown. Given that muscle mass is important in the development of the strength of bone, peripheral quantitative computed tomography (pQCT) was utilized to compare measurements of muscle compartments between NF1 individuals and controls. Forty individuals with NF1 (age 5-18 years) were evaluated. Cross-sectional measurements, at the 66% tibial site, were obtained using pQCT (XCT-2000, Stratec) and variables were compared to controls without NF1 ((age 5-18 years, N=380) using analysis-of-covariance controlling for age, height, Tanner stage, and gender. The NF1 cohort showed decreased total cross-sectional area [p<0.001], decreased muscle plus bone cross-sectional area [p<0.001], decreased muscle cross-sectional area [p<0.001], and decreased Stress Strain Index [p=0.010]. These data indicate that NF1 individuals have decreased muscle cross-sectional area and decreased bone strength than individuals without NF1.

Assessment of hepatic function in cystic fibrosis by lidocaine metabolism.

BACKGROUND: To determine hepatic drug metabolism in patients with cystic fibrosis, as measured by monoethylglycinexylidide formation after lidocaine injection and indocyanine green (ICG) clearance. METHODS: The following study is a case-control study, which included 19 patients with cystic fibrosis and 13 control subjects. Serum monoethylglycinexylidide concentration was measured after intravenous injection of 1 mg/kg (maximum, 50 mg) lidocaine. Indocyanine green (0.5 mg/kg) was injected concomitantly, and absorbance (805 nm) of serum was measured over time to determine its volume of distribution, serum half-life, and hepatic blood flow. RESULTS: Monoethylglycinexylidide formation was decreased in patients with cystic fibrosis compared with controls (39.4+/-16.9 microg/L versus 70.3+/-45.7 microg/L, mean +/- SD, respectively, P < 0.02). Indocyanine green half-life (4.6+/-2.7 min versus 3.0+/-1.0 min), volume of distribution (8.6+/-5.5 L versus 8.3+/-3.4 L), and hepatic blood flow (10.9+/-5.9 ml x kg(-1) x min(-1) versus 7.4+/-2.0 ml x kg(-1) x min(-1)) were similar in both groups. CONCLUSION: Monoethylglycinexylidide formation after lidocaine injection is impaired in patients with cystic fibrosis. This impairment may have clinical implications when using hepatically metabolized medications in patients with cystic fibrosis.

Elevated plasma endothelin-1 levels in sickle cell anemia: relationships to oxygen saturation and left ventricular hypertrophy.

Endothelin-1 (Et-1) is a vasoconstrictor produced by endothelial and vascular smooth muscle cells in response to hypoxia, which induces hypertrophy in cultured cardiac myocytes. We measured plasma Et-1 levels and left ventricular dimensions in 13 patients with sickle cell anemia (SCD) and in 12 African-American controls ages 16-29 years. Endothelin-1 concentrations are significantly higher in SCD subjects than controls (10.6 +/- 1.9 vs. 3.0 +/- 1.3 pmol/L). There was a negative correlation between oxygen saturation and Et-1 levels in SCD patients (r = -0.71, P = 0.01). SCD subjects have more dilated and hypertrophied hearts corrected for body surface area than controls as evidenced by significant increases in left ventricular end diastolic dimension (31 +/- 0.8 vs. 24 +/- 0.9 mm/m2, P < 0.001), left ventricular end systolic dimension (20 +/- 0.9 vs. 16 +/- 0.8 mm/m2, P = 0.002), left ventricular posterior wall thickness (5.0 +/- 0.1 vs. 4.0 +/- 0.1 mm/m2, P < 0.001), and left ventricular mass (125 +/- 7.2 vs. 69 +/- 5.1 g/m2, P < 0.001). The index of left ventricular function, the shortening fraction, was not different between groups (34 +/- 1.2% in SCD vs. 35 +/- 1.5% in controls). The correlation between left ventricular mass and levels of Et-1 in SCD subjects was not significant (r = 0.47, P = 0.121).

Hepatic function as assessed by lidocaine metabolism in sickle cell disease.

OBJECTIVE: To evaluate hepatic drug metabolism, as determined by the formation of monoethylglycinexylidide (MEGX) after lidocaine injection and indocyanine green (ICG) clearance, in patients with sickle cell disease. STUDY DESIGN: A case-control study including 19 patients with homozygous hemoglobin S, and 13 age- and sex-matched black control subjects. Serum MEGX concentration was measured after intravenous injection of 1 mg/kg (maximum 50 mg) lidocaine. ICG (0.5 mg/kg) was injected concomitantly and absorbance (805 nm) of serum was measured over time to determine its volume of distribution, serum half-life, and hepatic blood flow. RESULTS: MEGX formation at 15 minutes was decreased in patients with sickle cell disease compared with formation in the control subjects (39.9 +/- 18.0 vs 65.6 +/- 50.0 micrograms/L, respectively, p < 0.02). The volume of distribution of ICG was increased in patients with sickle cell disease compared with that in the control subjects (0.21 +/- 0.09 vs 0.11 +/- 0.03 L/kg, p < 0.01). This partly accounts for the decreased MEGX formation. The ICG half-life was similar in both groups (3.8 +/- 1.5 vs 3.1 +/- 1.0 min). Hepatic blood flow, derived from ICG clearance, was increased in sickle cell patients compared with that of the control subjects (12.2 +/- 4.5 vs 8.1 +/- 2.1 ml/kg/min, p < 0.01). CONCLUSION: Hepatic drug metabolism, as assessed by MEGX formation after lidocaine injection, is impaired in patients with sickle cell disease. This impairment may have clinical implications when using hepatically metabolized medications in patients with sickle cell disease.

Determination of fetal biparietal diameter without the use of ultrasound in squirrel monkeys.

This study evaluated manual caliper measurement of fetal BPD in Saimiri through the abdomen of the dam (TBPD) for correlation with paired ultrasound measurements, prediction of delivery date, subspecies variation, prediction of pregnancy outcome, and correlation between postpartum BPD and TBPD. Regression analysis revealed a close relationship between TBPD measurements and those obtained by ultrasound (P < 0.001). TBPD for Saimiri boliviensis boliviensis increased from a mean of 14.8 +/- 0.3 mm for 11 weeks prepartum to a delivery week measurement of 33.2 +/- 0.2mm. Delivery-week TBPD of Saimiri boliviensis peruviensis were significantly smaller than Saimiri sciureus sciureus (P < .05). Delivery week TBPD had a correlation coefficient of 0.64 with paired post-patrum measurements. No complications were associated with the technique. Delivery date could be predicted within two weeks. TBPD is an inexpensive, safe, rapid method of approximating fetal growth during the last half of pregnancy in Saimiri.

A review of pulse propagation in viscoelastic arteries with distributed flow leakage.

Current mathematical models for describing pulse propagation in arteries are summarized. These models include the effects of viscoelasticity, frequency dependent friction, and other factors. One factor that has not been previously considered is the effect of distributed flow leakage. This leakage is known to have a significant effect on pulse propagation in rigid tubes and it has been assumed to have a similar effect in compliant tubes. These effects are described here, along with the results of a recent study by these authors on the effects of the distributed flow leakage in compliant tubes.

Gunshot injuries in Mobile County, Alabama: 1985-1987.

Although much information about firearm fatalities has been published, few articles have characterized all types of gunshot victims, the weapons used, and the injuries sustained in a well-defined geopolitical unit. This study of 597 persons sustaining gunshot injuries serious enough to cause death or hospitalization in Mobile County Alabama during 1985-1987, addresses that deficit. The overall rate of these 597 seriously gunshot-injured victims was 53/100,000 population per annum. Of the 597 victims, 215 died, resulting in a rate of 18.9 per 100,000 population per annum. Demographic characteristics of the homicide victims, predominantly young black men, and the suicide victims, predominantly middle-aged and elderly white men, are similar to those reported from other parts of the country. Assault victims accounted for the largest (316) number of victims: again, young black men also constituted the largest demographic group among assault victims. Handguns accounted for 71% of the weapons used. No assault type weapons were employed. Head, neck, and chest wounds led with the greatest fatality rates. Information about nonfatally wounded victims, particularly data about the weapons, proved difficult to obtain. This was one of the many problems encountered in this type of project and, consequently, is discussed at some length. Additional population-based studies using prospective methods and a variety of investigators, including persons knowledgeable of firearms, are needed.

Effect of trimethoprim/sulphamethoxazole and hyperbaric oxygen on experimental Spiroplasma mirum encephalitis.

This study was undertaken to determine the susceptibility of experimentally induced Spiroplasma mirum infection in the rat to trimethoprim/sulfamethoxazole (TMP/SMX) in combination with hyperbaric oxygen (HBO). One-day-old Fisher 344 rats were intracerebrally inoculated with the GT-48 strain of S. mirum and were exposed to regimens employed combined antibiotic and HBO treatments. The exclusive use of TMP/SMX produced a significant reduction in mortality (P less than 0.0001) and an absence of clinical signs of infection. HBO in combination with TMP/SMX showed similar effect on mortality and no evident clinical disease. The addition of HBO did result in a significant decrease in spiroplasma brain titres but was no more effective in preventing the spiroplasma-induced fatal microcystic encephalopathy than when the antibiotics were used alone. The exclusive use of HBO produced a catastrophic mortality rate in the spiroplasma-infected rats, which is contrary to the effect of HBO on conventional bacterial infections.

The efficacy of postsplenectomy sepsis prophylactic measures: the role of penicillin.

The well documented increased susceptibility of the asplenic host to overwhelming sepsis by encapsulated organisms has led to three popular prophylactic measures in patients: 1) pneumococcal vaccination; 2) vaccination with oral penicillin prophylaxis; or 3) vaccination with penicillin use at the first sign of infection. An animal model (weanling CD-1 rats) was utilized to evaluate these prophylactic measures. One hundred sixty rats underwent splenectomy and were divided into four treatment groups: I) sham vaccination; II) pneumococcal vaccination; III) vaccination and IM penicillin 24 hours after intraperitoneal inoculation of 10(6) Streptococcus pneumoniae type III; IV) vaccination and IM penicillin starting 3 days before IP inoculation. Six days following the bacterial challenge survival rates by group were: I) 5%; II) 25%; III) 100%; IV) 100% (p less than 0.001 by phi 2 likelihood ratio). Mantel- Cox log rank analysis of survival curves yielded significant differences between all groups except III and IV (p less than 0.001). This study in weanling rats supports the use of penicillin in the asplenic host. Daily prophyactic penicillin or penicillin started at the first sign of infection appears to be equally effective. Randomized studies in humans would determine the best regimen.

The protective effect of pneumococcal vaccination following partial splenectomy.

Weanling CD-1 male rats were subjected to 100, 75, and 50% splenectomy. One week following splenectomy, animals received either a sham immunization with 0.1 ml NS or pneumococcal immunization with 0.1 ml of a polyvalent (23) vaccine. Eight weeks following surgery, all animals received an intraperitoneal inoculation with 10(6) Streptococcus pneumoniae Type 3 organisms and were observed for mortality. Significant differences in mortality were seen between sham and immunized animals undergoing 100 or 75% splenectomy, while in the 50% group a difference was noted which did not reach statistical significance (Mantel-Cox log rank test). Patients undergoing greater than 50% splenectomy may be afforded greater protection against overwhelming pneumococcal infections by immunization with pneumococcal vaccine.

Angiomas and von Recklinghausen neurofibromatosis.

The notion that vascular alterations represent a major feature of the pathogenesis of neurofibromatosis (NF) has been supported by an increasing number of observations. We present data about skin Morgan angiomas in the general US white population and a cohort of patients with NF-1 and their unaffected relatives. Among patients with NF-1, angiomas were significantly more common, but not so among unaffected relatives. The striking nature of skin angiomas in some patients is illustrated by a mother-daughter pair with innumerable lesions of early onset. The mother also had a large venous angioma and a constriction of the siphon of an internal carotid artery.

Neurotropic response of Spiroplasma mirum following peripheral inoculation in the rat.

Spiroplasma mirum experimentally produces a persistent brain infection in suckling rats when administered intracerebrally. In order to examine spiroplasma infection induced by a more natural route, suckling rats were inoculated both intraperitoneally and subcutaneously with strain GT-48. No mortality was recorded over a 50-day study period. Rats developed localized alopecia and showed a significant reduction in body weight. Minimal pathological alterations were observed in brain tissues, in addition to cataracts, retinal degeneration and panophthalmitis. Spiroplasmas were recovered from brain and spleen on day 2 following peripheral inoculation with highest titres in the spleen. Spleen titres significantly declined (p less than 0.022) during the 50-day study period. On day 50, brain titres exceeded those in the spleen. The attraction of spiroplasma to central nervous system tissues may be related to its nutritional dependence on sterols.

Epidemiology of inguinal hernia in preterm neonates.

We have studied the epidemiology of inguinal hernias in preterm infants. Inguinal hernias occur with increased frequency in infants less than or equal to 32 weeks' gestational age or less than or equal to 1,250 g birth weight. Among infants less than or equal to 32 weeks' gestational age, intrauterine growth retardation significantly increases the risk for development of inguinal hernias, especially in male infants. Our data demonstrate a previously unrecognized association between neonatal inguinal hernia and intrauterine growth retardation.

Capillary venous differences in neonatal neutrophil values.

Sixty paired venous and capillary total neutrophil counts (TNCs) were obtained from 30 healthy, term neonates on days 1 and 2 of life. Day 1 venous TNC (8,200 +/-- 3,800/cu mm) and capillary TNC (10,400 +/- 4,400/cu mm) were significantly different when examined by the paired t test as were day 2 venous TNC (8,700 +/- 3,300/cu mm) and capillary TNC (9,800 +/- 3,400/cu mm). Application of published reference ranges for capillary TNC to paired samples revealed a 35% incidence of differing clinical interpretations between paired TNCs. The application of capillary reference ranges to venous TNC may result in frequent misdiagnoses and inappropriate management. Venous reference ranges should be established.

Local cold exposure of Andean Indians during normal and simulated activities.

Thermal resonses of Andean Indians were measured during several customary tasks associated with cold exposure in the highlands of southern Peru. These included surface temperature measurements of women while they washed clothing in the river and similar measurements of men while they constructed a diversion channel in the same river. A third test measured the effects of alcohol consumption on body temperatures during light activity. Women maintained slightly warmer hand than foot temperatures. Men maintained nearly equal hand and foot temperatures during the exposure period. Among male subjects the foot rewarmed at a faster rate than the hand. The results from the field studies compared favorably with results from earlier laboratory exposure tests. Comparisons between the river water exposure tests for males and females showed a consistent pattern where females maintained warmer hand and foot temperatures than males. These findings were in accord with previous laboratory studies among Quechua Indians and with the findings reported for other ethnic groups who experience natural cold stress. Alcohol ingestion appeared to have minimal effect in mitigating cold stress response during light activity. This finding was counter to earlier laboratory tests of resting subjects.

The skin primates. XLIV. Numerical taxonomy of primate skin.

Data on 84 characteristics of the skin of 36 species of primates were extracted from a series of articles describing the histological and histochemical properties of the skin of primates. The data were subjected to a cluster analysis. The results were in reasonably good agreement with orthodox primate taxonomies although some exceptions were apparent. The species clustered into four main groups approximately comparable to Prosimii, Cercopithecoidea, pithecoidea, and Hominoidea are commensurate with standard taxonomic practice. Within the Ceboidea, however, the Atelinae and Alouattinae tend to group with the Hominoidea, Aotus and Saimiri show variable placements, and Callimico groups with the Callithricidae.