Age-related variation in limb bone diaphyseal structure among Inuit foragers from Point Hope, northern Alaska.

UNLABELLED: Age-related deterioration of limb bone diaphyseal structure is documented among precontact Inuit foragers from northern Alaska. These findings challenge the concept that bone loss and fracture susceptibility among modern Inuit stem from their transition away from a physically demanding traditional lifestyle toward a more sedentary Western lifestyle. INTRODUCTION: Skeletal fragility is rare among foragers and other traditional-living societies, likely due to their high physical activity levels. Among modern Inuit, however, severe bone loss and fractures are apparently common. This is possibly because of recent Western influences and increasing sedentism. To determine whether compromised bone structure and strength among the Inuit are indeed aberrant for a traditional-living group, data were collected on age-related variation in limb bone diaphyseal structure from a group predating Western influences. METHODS: Skeletons of 184 adults were analyzed from the Point Hope archaeological site. Mid-diaphyseal structure was measured in the humerus, radius, ulna, femur, and tibia using CT. Structural differences were assessed between young, middle-aged, and old individuals. RESULTS: In all bones examined, both females and males exhibited significant age-related reductions in bone quantity. With few exceptions, total bone (periosteal) area did not significantly increase between young and old age in either sex, nor did geometric components of bending rigidity (second moments of area). CONCLUSIONS: While the physically demanding lifestyles of certain traditional-living groups may protect against bone loss and fracture susceptibility, this is not the case among the Inuit. It remains possible, however, that Western characteristics of the modern Inuit lifestyle exacerbate age-related skeletal deterioration.

Electron transfer. 147. Reductions with gallium(I).

Solutions 0.03-0.05 M in gallium(I) can be generated by treatment of the "mixed" halide Ga(I)Ga(III)Cl(4) with cold water under argon and then removing the precipitated metallic gallium and Ga(OH)(3) by centrifugation. Ga(I) is lost from such preparations with a half-life of about 3 h at 0 degrees C. These solutions, which may be handled by conventional techniques, readily reduce I(3)(-), IrCl(6)(2)(-), Fe(bipy)(3)(3+), Fe(NCS)(2+), aquacob(III)alamin, and a group of ring-substituted derivatives of Ru(NH(3))(5)(py)(3+) but are inert to (NH(3))(5)CoCl(2+) and (NH(3))(5)CoBr(2+). All reactions give Ga(III). Reduction of HCrO(4)(-) in 2-ethyl-2-hydroxybutanoate buffers (pH 3.6) yields a Cr(IV) chelate of the buffering anion but forms Cr(III) when carried out in 0.01 M H(+). Reactions of le(-) oxidants proceed via successive single changes with the conversion Ga(II) --> Ga(III) much more rapid than Ga(I) --> Ga(II). Only for the reactions of I(3)(-) and Fe(NCS)(2+) is there evidence for redox bridging.

Electron transfer. 144. Reductions with germanium(II).

Solutions 0.2-0.4 M in Ge(II) and 6 M in HCl, generated by reaction of Ge(IV) with H3PO2, are stable for more than 3 weeks and can be diluted 200-fold with dilute HCl to give GeCl3- preparations to be used in redox studies. Kinetic profiles for the reduction of Fe(III) by Ge(II), as catalyzed by Cu(II), implicate the odd-electron intermediate, Ge(III), which is formed from Cu(II) and Ge(II) (k = 30 M-1 s-1 in 0.5 M HCl at 24 degrees C) and which is consumed by reaction with Fe(III) (k = 6 x 10(2) M-1 s-1). A slower direct reaction between Ge(II) and Fe(III) (k = 0.66 M-1 s-1) can be detected in 1.0 M HCl. The reaction of Ge(II) with I3- in 0.01-0.50 M iodide is zero order in oxidant and appears to proceed via a rate-determining heterolysis of a Ge(II)-OH2 species (k = 0.045 s-1) which is subject to H(+)-catalysis. Reductions of IrCl6(2-) and PtCl6(2-) by Ge(II) are strongly Cl(-)-catalyzed. The Ir(IV) reaction proceeds through a pair of 1e- changes, of which the initial conversion to Ge(III) is rate-determining, whereas the Pt(IV) oxidant probably utilizes (at least in part) an inner-sphere PtIV-Cl-GeII bridge in which chlorine is transferred (as Cl+) from oxidant to reductant. The 2e- reagent, Ge(II), like its 5s2 counterpart, In(I), can partake in 1e- transactions, but requires more severe constraints: the coreagent must be more powerfully oxidizing and the reaction medium more halide-rich.

Electron transfer. 140. Reactions of riboflavin with metal center reductants.

Riboflavin (I) is reduced in separable steps by indium(I), vanadium(II), europium(II), and titanium(III) in 0.02-1.0 M H+, yielding first the radical ion, II (lambdamax = 495 nm), and then the dihydro compound, III. The initial reduction with InI yields 2 equiv of the radical, but kinetic profiles exhibit no irregularity due to intervention of In(II), indicating that participation by the dipositive state is much more rapid than the In(I) reaction. Predominant paths involve the protonated form of the flavin, RbH+, and that of the radical, RbH2.+. Formation of the radical with excess V(II) and Ti(III) (but not with In(I)) is strongly autocatalytic, reflecting rapid comproportionation involving the flavin and the dihydro compound. The V(II) and Ti(III) rates for both steps greatly exceed the substitution-controlled limits for these states and therefore pertain to outer-sphere processes. The very high ratio kEu/kv for the first step, however, points to an inner-sphere reduction by the lanthanide cation. A kinetic inversion is observed for In(I) (kRbH.+ > kRbH2.+), implying a bridged reduction path for the initial step with this center as well.

Electron transfer. 141. Reactions of indium(I) with transition metal center oxidants.

Aqueous solutions of the hypovalent state In(I) reduce a series of complexes of Fe(III) and selected derivatives of Ir(IV), Cr(V), Pt(IV), Ag(III), and Ni(IV). All reactions yield In(III). Ions derived from Fe(III) and Ir(IV) undergo net le- conversions, whereas the other oxidants change by two units. Reductions of Fe(III) are strongly promoted by increasing pH or by adding Cl-, Br-, NCS-, or N3-. Reaction appears to proceed through monoligated complexes, FeIII(Lig-)2+, and the kinetic response to alteration of added ligand indicates initiation mainly via a bridged transition state FeIII-Lig-InI. Oxidations by Fe(CN)6(3-) are exceptionally rapid, those by FeIII(EDTA) are unusually slow, and redox is blocked by addition of excess F-. Reduction of IrCl6(2-) proceeds somewhat more slowly than predicted by the marcus model for outer-sphere reactions. Conversions of the 2e- oxidants are rapid. For these, multistep routes initiated by le- changes are reasonable, but direct 2e-paths involving oxygen transfer (from CrVO) or Cl+ transfer (from PtCl6(2-)) cannot be ruled out. Whether inner-sphere 2e- transactions without transfer of atomic species can be competitive remains an open question.

Electron Transfer. 129. Copper Catalysis in the Thiol Reduction of Oxime-Bound Nickel(IV)(1).

Solutions of the Ni(IV) complex of the dianion of 2,6-diacetylpyridine dioxime (chelate II in text) are reduced very slowly by 2-aminoethanethiol at pH 2.3-3.0, but this reaction is catalyzed dramatically and specifically by dissolved copper, with Cu(I) the active reductant. When the [thiol]/[Ni(IV)] ratio exceeds 1.6, each Ni(IV) oxidizes two molecules of thiol, forming Ni(II) and R(2)S(2). At low concentrations of catalyst and reductant, reaction profiles are almost exponential, but at higher concentrations of either, curves become progressively more nearly linear. Reactions are sharply retarded by increases in acidity. Profiles for 14 runs, carried out with [H(+)] = 0.001-0.0040 M, [Ni(IV)] = (0.94-1.2) x 10(-)(5) M, [thiol] = (2.0-32) x 10(-)(4) M, and [Cu(2+)] = (2.5-80) x 10(-)(6)M, are consistent with a reaction sequence (eqs 2-10 in text) in which Cu(I) is generated in competing homolyses of the complexes Cu(II)(SRH) and Cu(II)(SRH)(2). Reduction of Ni(IV) appears then to proceed through a Ni(IV)Cu(I) adduct, which can undergo electron transfer (yielding Ni(III) and Cu(II)), either in a unimolecular fashion or, alternatively, as a result of attack by a second Cu(I) species. The Ni(IV)Cu(I) + Cu(I) process is reflected in approach to second-order dependences on [Cu(II)] and [thiol] (which generate Cu(I)) at high concentrations of these reagents. Reductions of the Ni(III) intermediate are taken to be much more rapid than those of Ni(IV). Kinetic trends in the present system stand in contrast to the more familiar catalytic patterns such as those seen when the same combination of thiol and catalyst is used to reduce superoxo complexes of cobalt(III). With the latter reactions, decay profiles for the oxidant tend to be exponential at high reagent concentrations but approach linearity at low.

Magnetic resonance imaging of the hip after displaced femoral neck fractures.

This study was designed to determine the sensitivity of magnetic resonance imaging (MRI) in the detection of ischemia or avascular necrosis after displaced intracapsular hip fractures. Magnetic resonance imaging was performed on 20 patients who had hemiarthroplasties performed for Garden IV intracapsular fractures. Sixteen patients had in vivo coronal T1-weighted spin-echo imaging from the day of injury to 60 days after fracture. After hemiarthroplasty, all 20 resected femoral heads had in vitro T1 imaging. A coronal slab was then cut from the center of the femoral head and studied histologically. The in vivo, in vitro, and histologic slides correlated well. None of the MRI images depicted areas of ischemia or avascular necrosis in patterns observed in nontraumatic necrosis. Avascular bone can be indistinguishable from normal bone in both MRI and histologic sections for a considerable amount of time after vascular insult. Magnetic resonance imaging is not a prognosticator for posttraumatic osteonecrosis in the first two weeks after fracture.

Diagnosis of occult fractures about the hip. Magnetic resonance imaging compared with bone-scanning.

Sixty-two consecutively seen patients in whom a fracture about the hip was clinically suspected, but in whom the radiographic findings were negative, were examined with both magnetic resonance imaging and bone-scanning. The magnetic resonance-imaging studies, consisting of T1-weighted coronal sections, were done within twenty-four hours after admission to the hospital, and the bone scans, within seventy-two hours after admission. There were twenty-three men and thirty-nine women. Thirty-six patients who had evidence of a fracture on the magnetic resonance-imaging study also had a positive bone scan initially. Twenty-three patients who had a negative finding on the magnetic resonance-imaging study had a corresponding negative bone scan. Two additional patients had evidence of avascular necrosis of the femoral head on both the magnetic resonance image and the bone scan, and they were managed non-operatively. One patient had a positive magnetic resonance image and a negative bone scan twenty-four hours after admission. A repeat bone scan, which was made six days later, was positive for a fracture of the femoral neck and the patient was managed with internal fixation. Magnetic resonance imaging was as accurate as bone-scanning in the assessment of occult fractures of the hip. The magnetic resonance imaging took less than fifteen minutes to perform, and it was tolerated well by the patient. Magnetic resonance imaging provides an early diagnosis of occult fractures about the hip and may decrease the length of the stay in the hospital by expediting definitive treatment.

Septic subdeltoid bursitis.

Four cases of septic subdeltoid bursitis are described. Clinical presentations, microbiology, and therapies are reviewed for these cases as well as for the six previously reported cases in the literature. The etiology of septic subdeltoid bursitis was related to bacteremia, trauma, or immune incompetence. Compared with septic oelcranon and prepatellar bursitis, septic subdeltoid bursitis was associated with a more profound inflammatory reaction in the bursa, required more sophisticated diagnostic imaging, and necessitated more aggressive therapy. Appropriate therapy generally resulted in favorable outcomes.

Double anal canal: complication of rectal fecalith.

Fecaliths and stercoraceous ulcerations are well-known complications of chronic constipation. The authors present the case of a double anal canal in an elderly man. This anorectal fistula (complex anal fistula) developed as a complication of an impacted rectal fecalith with resultant stercoraceous ulceration. Eventually, a persistent epithelialized canal developed and was demonstrated at double-contrast barium enema examination. The patient remained continent at all times.

Case report 671: Arteriovenous malformation of the right lower extremity with associated intraosseous hemangiomatosis.

Since extensive involvement of the lower extremity with arteriovenous malformations occurs often combined with the potential risk of hemorrhage, transcatheter embolization has become an attractive alternative to surgical resection [7, 9]. We describe an unusual case of extensive intraosseous hemangiomatosis, with a concomitant arteriovenous malformation that presented in a 35-year-old woman as synovitis in a knee. MR images demonstrated that the lesion was far more extensive than originally suggested and directed the subsequent biopsy and embolization. The differential diagnosis was discussed and the subject of intraosseous hemangiomatosis with associated AVM was considered in some detail.

Unilateral osteonecrosis in a patient with bilateral os centrale carpi.

Accessory carpal bones, although uncommon, are usually of no clinical significance. This report describes a patient who had bilateral presence of the accessory bone called the os centrale carpi. The patient was seen with disabling pain in the dominant right wrist and both radiologic and pathologic findings showed osteonecrosis and secondary degenerative arthritis. His left wrist was asymptomatic and the accessory ossicle was normal in appearance. We have not been able to discover any cases in the literature describing the development of unilateral osteonecrosis in a patient with bilateral os centrale capri.

Role of routine percutaneous hip aspirations prior to prosthesis revision.

We undertook a retrospective review of 78 percutaneous hip aspirations performed as a prerequisite to prosthetic revision or replacement. Although the majority of the patients were already scheduled for revision or replacement, many aspirations were requested as part of the "routine" algorithm in the evaluation of a painful hip. Cultures from the aspirated fluid were compared with those obtained intraoperatively (where possible) and to the clinical suspicion of infection. Many of the selected patients had clinical and/or radiographic indications of pain. Our results yielded no evidence of infection (0%) when there was no clinical suspicion of infection (60 patients). Clinical suspicion for infection was high in 7 patients; aspirates demonstrated infection in 5 of them. One aspiration was false negative for infection, but subsequent intraoperative cultures were positive. When the clinical suspicion was intermediate or equivocal (11 patients), results were negative in 9 and positive in 2, both at aspiration and intraoperatively. We contend that routine percutaneous hip aspirations do not need to be performed when a prosthetic revision or replacement is contemplated if the clinical suspicion for infection is low. Hip aspiration and arthrography should not be eliminated, however, when the clinical suspicion is equivocal or high or when there is no apparent cause for a painful prosthesis.

MR appearance of bilateral periscapular elastofibromas.

Elastofibroma, although unusual, should be considered in the diagnosis of a periscapular mass. The ability of magnetic resonance to detect and diagnose these lesions is demonstrated.

The role of diskography after negative postmyelography CT scans: retrospective review.

Review of our records for a 2-year period (1985-1986) yielded 15 patients in whom unequivocally normal myelograms and postmetrizamide CT scans had been obtained before diskography. In none of these patients was the diskogram or postdiskography CT scan positive for either central, posterolateral, or extreme lateral disk herniation. It was our experience that, with the new-generation, improved-resolution CT scanners with multiplanar reconstruction capabilities, diskography added no additional information, did not influence the surgeon's decision to operate, and was not a painless or innocuous procedure. When an entirely negative, technically flawless postcontrast CT scan is obtained in a patient with back pain, diskography should not be performed, as it offers no further information.