Amputations of the foot and ankle. Current status

Doppler assessment of ankle and foot systolic pressure is a practical aid in the evaluation of neurocirculatory problems. If the ratio of ankle pressure to arm pressure is over 0.45, more than 90 per cent of operative procedures will heal. Intraoperative testing of blood supply aids in determining level of amputation. Healing results in 80 per cent of cases if bleeding occurs in the skin within three minutes after release of tourniquet. With vigorous debridement of infected soft tissue and bone, the remaining tissue will often heal in local foot operations. A high percentage of patients with neuro-circulation disorders become bilateral amputees. Partial foot and Syme level amputations allow these patients to remain prosthetic users. Function tests show the Syme amputee to be superior in stride length, velocity, cadence and oxygen uptake when compared with the below-knee and above-knee amputees. The criteria of McKittrick must be followed carefully to ensure healing of transmetartarsal amputations.

Neurocirculatory disorders of the foot

There is a simple rationale for care of the dysvascular neuropathic foot. Either prevention or correction of deformities, or both, is of primary importance in the insensitive or poorly healing foot. Control of edema is necessary to achieve maximum healing potential. There are tools at hand to allow the orthopedic surgeon to judge arterial supply in addition to his clinical judgment. Interest in defensive footwear, appreciation of interface forces, and the application of standard operative techniques to this ever-present population can result in significant improvement in patient care.

Unusual amino acid usage in the variable regions of mercury-binding antibodies

Monoclonal antibodies (mAb) specific for mercuric ions were isolated from BALB/c mice injected with a mercury-containing, hapten-carrier complex. The antibodies reacted by enzyme-linked immunosorbent assay with bovine serum albumin-glutathione-mercuric chloride (BSA-GSH-HgCl) but not with BSA-GSH without mercury. Nucleotide sequences from polymerase chain reaction products encoding six of the antibody heavy-chain variable regions and seven light-chain variable regions revealed that all the antibodies contained an unpaired cysteine residue in one hypervariable region, which is unusual for murine antibodies. Mutagenesis of the cysteine to either tyrosine or serine in one of the Hg-binding antibodies, mAb 4A10, eliminated mercury binding. However, of two influenza-specific antibodies that contain cysteine residues at the same position as mAb 4A10, one reacted with mercury, although not so strongly as 4A10, whereas the other did not react at all. These results suggested that, in addition to an unpaired cysteine, there are other structural features, not yet identified, that are important for creating an appropriate environment for mercury binding. The antibodies described here could be useful for investigating mechanisms of metal-protein interactions and for characterizing antibody responses to structurally simple haptens.

Bioassay for growth hormone releasing hormone (GHRH) using a recombinant receptor and cAMP-responsive reporter system

Growth hormone releasing hormone (GHRH) receptors are members of the G-protein receptor family that use cAMP as a second messenger. A human fetal kidney 293-derived cell line stably expressing the porcine GHRH receptor (pGHRHr/293 cells) and a cAMP-responsive reporter system were used to develop a bioassay for human GHRH. The reporter system (ph alpha180SEAP) was constructed by subcloning the tandem cAMP response elements from the human glycoprotein hormone alpha subunit gene promoter (h alpha180) upstream from the secreted alkaline phosphatase cDNA of reporter plasmid pSEAP-Basic. To generate a stable cell line expressing both the GHRH receptor and SEAP reporter system, a DNA fragment from pPUR that confers puromycin resistance was subcloned downstream from the reporter construct of ph alpha180SEAP. Tranfection of ph alpha180SEAPpur into pGHRHr/293 cells yielded pGHRHr/SEAP/293 cell lines that responded to recombinant GHRH with dose-dependent increases in SEAP activity. The GHRH receptor-SEAP reporter bioassay was compared to a conventional bioassay using cultured rat anterior pituitary cells. Synthetic and recombinant GHRH induced a 3.1-fold increase in growth hormone release by rat pituitary cells with ED50's of 3.6 and 2.2 x 10(-10) M, respectively. Recombinant GHRH was 1.7 +/- 0.7 times more potent than synthetic GHRH in the pituitary cell bioassay. In an analogous experiment, pGHRHr/SEAP/293 cells responded to synthetic and recombinant GHRH with a 9.1-fold increase in SEAP activity. The ED50's were 7.8 and 4.3 x 10(-11) M, respectively, with recombinant GHRH being 1.8 +/- 0.1 times more potent than the synthetic preparation. Thus, the GHRH receptor-SEAP reporter bioassay is a sensitive, accurate, precise and efficient method for measuring GHRH biological activity.

Characteristics of Modified Leghemoglobins Isolated from Soybean (Glycine max Merr.) Root Nodules

Hemoprotein derivatives of an abundant soybean (Glycine max Merr.) root nodule leghemoglobin, Lba, were studied for their modified spectral characteristics and physical properties. Three modified hemoprotein derivatives of Lba (Lbam1, Lbam2, and Lbam3) were purified by preparative isoelectric focusing. The ferric forms of these pigments were green and exhibited anomalous spectra in the visible region as compared to the Lba3+ forms. These modified pigments showed a hypochromic shift of 10 nm for the charge transfer absorption maximum; however, differences were not apparent in the Soret region. Upon binding with nicotinate, the [alpha] and [beta] bands were shifted significantly into the red region as compared to the Lba3+ nicotinate complex. The three Lbam fractions were reduced by dithionite or by NADH in the presence of riboflavin. Lbam2+ also bound nicotinate and displayed absorption spectra indistinguishable from those of Lba2+ nicotinate. In contrast to Lba2+, Lbam2+ displayed aberrant spectra when bound with either O2 or CO. These complexes exhibited a prominent charge transfer band at approximately 620 nm and failed to exhibit spectra characteristic of Lba2+O2 and Lba2+CO. The protein moiety of these modified pigments was intact because their tyrosine/tryptophan ratios and their amino acid compositions were identical with those of Lba, nor were differences observed in the peptide profiles resulting from trypsin digests of purified Lba and Lbams. Automated Edman degradation of selected peaks further confirmed the intactness of the protein backbone including the absence of deamination. Pyridine hemochromogen for heme from Lbams could be formed, and the spectra displayed distinct differences compared to those of Lba. A new peak at 580 nm and a loss of a peak at 480 nm were observed for all three Lbams.

Neuropathic calcaneal tuberosity avulsion fractures

Avulsion of a calcaneal tuberosity can be the initial presentation of a neuropathic fracture. Neuropathic fracture should be investigated in patients who appear without a history of significant indirect or direct trauma. Neuropathic fractures should always be considered in patients with diabetes mellitus. The diagnosis of neuropathic calcaneal tuberosity avulsion fracture alters the prognosis and treatment of this injury. Two cases of bilateral fracture avulsions are reported to emphasize problems in diagnosis and treatment.

Management of neuropathic arthropathy with the Charcot Restraint Orthotic Walker

A recently designed Charcot Restraint Orthotic Walker (CROW) was used in the treatment of 18 patients with diabetic neuroarthropathy involving the foot and ankle. Eight of these patients had no surgery before the use of the CROW. In ten patients, the device was used for prolonged immobilization after surgery for complications of neuropathic joint disease. The CROW is a rigid, custom, full-foot enclosure ankle-foot orthosis. It was used after an initial period of cast immobilization. The CROW effectively controls limb edema, returns the patient to ambulatory activities, and prevents significant progression of deformity. All patients rated their satisfaction with the device as good or excellent. The CROW is an attractive alternative to currently used methods to provide the prolonged immobilization and protection necessary for healing in neuropathic arthropathy.

Gene fusions with human carbonic anhydrase II for efficient expression and rapid single-step recovery of recombinant proteins: expression of the Escherichia coli F1-ATPase epsilon subunit

A new expression vector was constructed which allows the overproduction in Escherichia coli of tripartite proteins consisting of human carbonic anhydrase isozyme II (hCAII), a peptide linker containing an enterokinase cleavage site, and a target protein of interest. Carbonic anhydrase is soluble and stable in E. coli and serves as a highly specific purification tag in the recovery of the fusion protein by a single affinity chromatography step. The enterokinase cleavage site was engineered into the construct to allow accurate and efficient release of the target protein. To demonstrate the practical value of this vector, the E. coli F1-ATPase epsilon subunit was expressed as a fusion with hCAII. After a single purification step, biologically active recombinant E. coli F1-ATPase epsilon subunit was recovered following proteolytic removal of the hCAII moiety.

The safety of the Esmarch tourniquet

The use of an Esmarch bandage as a tourniquet in surgery has been criticized. Many authors claim that the pressures under the Esmarch are inconsistent and may be extremely high. We have seen few, if any, problems from the use of an Esmarch in surgery of the foot and ankle. The purpose of this study was to evaluate the pressures generated under the Esmarch tourniquet in a situation that mimics its clinical application, and to determine whether pressures of appropriate magnitude and consistency are obtained in order to recommend its continued use in surgery. Ten volunteers performed numerous applications of the Esmarch. The number of wraps and the width of the Esmarch bandage used were varied. The Esmarch was applied as it would be for a surgical case. Pressures directly beneath the Esmarch were recorded 8 cm proximal to the distal tip of the medial malleolus. Considering all volunteers and all pressures generated, a 3-in Esmarch applied with three wraps gave a mean pressure (+/- SD) of 225 +/- 46 mm Hg. A 3-in Esmarch applied with four wraps gave a mean pressure of 291 +/- 53 mm Hg. A 4-in Esmarch applied with three wraps gave a mean pressure of 233 +/- 35 mm Hg, and a 4-in Esmarch with four wraps gave a mean pressure of 284 +/- 42 mm Hg. The maximum pressures generated by any individual were as follows: 3-in three wraps, 321 mm Hg; 3-in four wraps, 413 mm Hg; 4-in three wraps, 328 mm Hg; and 4-in four wraps, 380 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning and nucleotide sequence of the Vibrio proteolyticus aminopeptidase gene

The gene encoding the Vibrio proteolyticus aminopeptidase was cloned and sequenced and its amino acid sequence was deduced. The gene encodes a 54 kDa protein, larger than the previously reported size of 30 kDa for the purified aminopeptidase. Sequence alignments revealed a 43-45% homology with two other Vibrio sp. extracellular proteinases.

Monoclonal antibodies specific for mercuric ions

Monoclonal antibodies (mAbs) that react with soluble mercuric ions have been produced by injection of BALB/c mice with a hapten-carrier complex designed to maximize exposure of the metal to the immune system. Three hybridomas producing antibodies that reacted with bovine serum albumin (BSA)-glutathione-HgCl, but not with BSA-glutathione, were isolated from the spleen of a mouse given multiple injections with glutathione-HgCl conjugated to keyhole limpet hemocyanin. Stable subclones were established from two of these antibodies, designated mAb 4A10 and mAb 1F10. The binding of both antibodies to immobilized BSA-glutathione-HgCl was inhibited by soluble HgCl2, and dissociation constants for mercuric chloride binding were 2.3 and 3.7 nM for mAbs 4A10 and 1F10, respectively. Both antibodies bound mercuric acetate with similar affinities, demonstrating that the antibodies were capable of binding to mercuric ions in the presence of a different counterion than the one used in the immunogen. Reactions were not observed with other metal cations by either antibody. These data demonstrate the successful induction of antibodies that react very specifically with mercuric ions in solution regardless of the presence of a carrier.

Detection of mercuric ions in water by ELISA with a mercury-specific antibody

An immunoassay that detects mercuric ions in water at concentrations of 0.5 ppb and above is described. The assay utilizes a monoclonal antibody that binds specifically to mercuric ions immobilized in wells of microtiter plates. Within the range of 0.5-10 ppb mercury, the absorbance in the enzyme-linked immunosorbent assay (ELISA) is linear to the log of the mercuric ion concentration. The quantitation of mercury by ELISA correlates closely with results from cold-vapor atomic absorption. Other divalent metal cations do not interfere with the assay, although there is interference in the presence of 1 mM chloride ions. The optimum pH for mercury detection is 7.0, although 2 ppb mercury can be detected over a wide pH range. The assay is as sensitive as cold-vapor atomic absorption for mercury detection and can be performed with only 100 microliters of sample.

Avian alcohol dehydrogenase. Characterization of the quail enzyme, functional interpretations, and relationships to the different classes of mammalian alcohol dehydrogenase

The primary structure of the major quail liver alcohol dehydrogenase was determined. It is a long-chain, zinc-containing alcohol dehydrogenase of the type occurring also in mammals and hence allows judgement of the gene duplications giving rise to the classes of the human alcohol dehydrogenase system. The avian form is most closely related to the class I mammalian enzyme (72-75% residue identity), least related to class II (60% identity), and intermediately related to class III (64-65% identity). This pattern distinguishes the mammalian enzyme classes and separates classes I and II in particular. In addition to the generally larger similarities with class I, the avian enzyme exhibits certain residue patterns otherwise typical of the other classes, including an extra Trp residue, present in both class II and III but not in class I, with a corresponding increase in the UV absorbance. The avian enzyme further shows that a Gly residue at position 260 previously considered strictly conserved in alcohol dehydrogenases can be exchanged with Lys. However, zinc-binding residues, coenzyme-binding residues, and to a large extent substrate-binding residues are unchanged in the avian enzyme, suggesting its functional properties to be related to those of the class I mammalian alcohol dehydrogenases. In contrast, the areas of subunit interactions in the dimers differ substantially. These results show that (a) the vertebrate enzyme classes are of distant origin, (b) the submammalian enzyme exhibits partly mixed properties in relation to the classes, and (c) the three mammalian enzyme classes are not as equidistantly related as initially apparent but suggest origins from two sublevels.

Characterization of Coturnix quail liver alcohol dehydrogenase enzymes

Livers from male or female Coturnix quail possess up to four electrophoretically distinct bands of alcohol dehydrogenase (ADH) activity. Three pyrazole-sensitive bands of enzymatic activity, designated ADH-1, ADH-2, and ADH-3, are cathodic at pH 8.2, and the fourth, ADH-An, is neutral to slightly anodic and insensitive to pyrazole. ADH-2 and ADH-3, and occasionally ADH-1, are present in livers from immature females. The predominant enzyme in immature male livers is ADH-3. At sexual maturity all three pyrazole-sensitive enzymes are present in livers from male birds, and livers from females possess predominantly ADH-3. ADH-2 and ADH-3, purified from female livers, are dimers of 80,000 daltons possessing 4 mol of Zn2+/mol of native protein. Both ADH-2 and ADH-3 were inhibited by 4-methylpyrazole with KI values of 430 and 335 nM, respectively. These values are similar to those of human class I isoenzymes. Neither enzyme oxidized methanol or ethylene glycol, which distinguished them from mammalian pyrazole-sensitive ADH isoenzymes. Both ADH-2 and ADH-3 showed specificity toward hydrophobic primary alcohols and were most active toward benzyl alcohol and n-octanol.

Aspergillus niger sulfhydryl oxidase

A procedure for the isolation of a sulfhydryl oxidase from an Aspergillus niger cell suspension involved three major steps and yielded enzyme preparations exhibiting a single but diffuse protein-containing zone when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with a subunit molecular weight estimated to be 53,000. Sedimentation equilibrium experiments indicated a native molecular weight of 106,000. Analyses for sugar residues showed that the enzyme is a glycoprotein, containing 20.3% neutral hexose and 1.9% aminohexose by weight. This enzyme catalyzed the conversion of reduced glutathione (GSH) to its disulfide form, with concomitant consumption of O2 and release of H2O2. The ratio of GSH consumed to H2O2 produced was determined to be 2:1. At 25 degrees C, the optimum pH for the oxidation of GSH was 5.5. Under these conditions, the enzyme had a Michaelis constant of 0.3 mM for GSH. Other low molecular weight thiol compounds (cysteine, dithiothreitol, and 2-mercaptoethanol) were also oxidized, but the Michaelis constants for these substrates were substantially higher than that for GSH under identical conditions of temperature and pH. The rate of reactivation of reductively denatured ribonuclease A was enhanced by the presence of sulfhydryl oxidase, indicating that the latter is capable of oxidizing protein-associated thiol groups. The UV-visible spectrum of sulfhydryl oxidase solution had absorbance maxima at 274, 364.5, and 442.5 nm and was otherwise characteristic of the spectra of known flavoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

The diabetic foot

Amputation of the lower extremity is more frequent in diabetic patients than in the general population. Causative factors include foot deformities, neuropathy, dysvascularity, infection, and gangrene. A grading and treatment program is outlined for aid in treating the lesions that develop in these feet.

Bacteroids Are Stable during Dark-Induced Senescence of Soybean Root Nodules

Physiological and biochemical markers of metabolic competence were assayed in bacteroids isolated from root nodules of control, dark-stressed, and recovered plants of Glycine max Merr. cv ;Woodworth.' Nitrogenase-dependent acetylene reduction by the whole plant decreased to 8% of control rates after 4 days of dark stress and could not be detected in plants dark stressed for 8 days. However, in bacteroids isolated anaerobically, almost 50% of initial acetylene reduction activity remained after 4 days of dark stress but was totally lost after 8 days of dark stress. Bacteroid acetylene reduction activity recovered faster than whole plant acetylene reduction activity when plants were dark stressed for 8 days and returned to a normal light regimen. Significant changes were not measured in bacteroid respiration, protein content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles, or in bacteroid proteolytic activity throughout the experiment. Immunoblots of bacteroid extracts revealed the presence of nitrogenase component II in control, 4-day dark-stressed, and 8-day dark-stressed plants that were allowed to recover under a normal light regimen, but not in 8-day dark-stressed plants. Our data indicate that dark stress does not greatly affect bacteroid metabolism or induce bacteroid senescence.

High-performance liquid chromatographic separation of leghemoglobins from soybean root nodules

A crude fraction of soybean nodule ferri-leghemoglobin was absorbed onto a commercial DEAE HPLC column at pH 8.0, and resolved into eight isoprotein fractions. The identity of the leghemoglobins were determined by their order of elution from the DEAE column and by isoelectric focusing, using isoprotein standards isolated by conventional procedures. The three isoproteins of the c complex, c1, c2, c3, were not resolved. Unexpected heme containing proteins eluted just after leghemoglobin a and the c complex. These components possessed proteins similar to leghemoglobin a and the c complex, respectively, as judged by isoelectric focusing and absorbance spectra of the ferri and ferrous forms. The components designated leghemoglobin a' and leghemoglobin c' were also differentiated from leghemoglobin a and c by reverse-phase HPLC in a C18 column. Amounts of protein for the DEAE HPLC column ranged from 10 micrograms to 20 mg and sample volumes ranged from 2 to 250 microliters. The time required for chromatography varied depending on the gradient used, but never exceeded 40 min for samples up to 5 mg protein or 120 min for samples containing 5 to 20 mg protein. Due to the sensitivity of detection at 403 nm and leghemoglobins being the predominant chromophore at that wavelength, it was possible to quantitate levels of individual leghemoglobins in samples extracted from single nodules (ca. 15 to 65 mg fresh weight tissue). Quantitation was performed by interfacing the spectrophotometer output (10 mV) to a microcomputer and using commercially available software.

Spectral and kinetic studies of metal-substituted Aeromonas aminopeptidase: nonidentical, interacting metal-binding sites

Apoenzyme prepared by removal of the 2 mol of Zn2+/mol from Aeromonas aminopeptidase is inactive. Addition of Zn2+ reactivates it completely, and reconstitution with Co2+, Ni2+, or Cu2+ results in a 5.0-, 9.8-, and 10-fold more active enzyme than native aminopeptidase, respectively. Equilibrium dialysis and spectral titration experiments with Co2+ confirm the stoichiometry of 2 mol of metal/mol. The addition of only 1 mol of metal/mol completely restores activity characteristic of the particular metal. Interaction between the two sites, however, causes hyperactivation; thus, addition of 1 mol of Zn2+/mol subsequent to 1 mol of Co2+, Ni2+, or Cu2+ per mole increases activity 3.2-, 42-, or 59-fold, respectively. The cobalt absorption spectrum has a peak of 527 nm with a molar absorptivity of 53 M-1 cm-1 for 1 mol of cobalt/mol, which increases to 82 M-1 cm-1 for a second cobalt atom and is unchanged by further addition of Co2+. Circular dichroic (CD) and magnetic CD spectra indicate that the first Co2+ binding site is tetrahedral-like and that the second is octahedral-like. Stoichiometric quantities of 1-butylboronic acid, a transition-state analogue inhibitor of the enzyme [Baker, J. O., & Prescott, J. M. (1983) Biochemistry 22, 5322], profoundly affects absorption, CD, and MCD spectra, but n-valeramide, a substrate analogue inhibitor, has no effect. These findings suggest that the tetrahedral-like site is catalytic and the other octahedral-like site is regulatory or structural.

Physical and enzymatic properties of a class III isozyme of human liver alcohol dehydrogenase: chi-ADH

chi-Alcohol dehydrogenase (chi-ADH), a class III isozyme characterized by its anodic electrophoretic mobility and lack of inhibition by 4-methylpyrazole, has been isolated from human liver and purified to homogeneity in a reducing medium. chi-ADH resembles other human liver ADH isozymes of classes I and II with respect to its molecular weight, dimeric structure, stoichiometry of zinc and NADH binding, and pH optima for the oxidation of alcohols. This homodimer exhibits subtle differences in its absorption spectrum and amino acid composition relative to those of other human isozymes but differs markedly from their specificity toward alcohols and aldehydes. chi-ADH oxidizes ethanol very poorly. The reaction is bimolecular, and an apparent Km cannot be discerned up to 2.3 M ethanol. The enzyme is inactive toward methanol, ethylene glycol, digitoxigenin, digoxigenin, and gitoxigenin , but alcohols with carbon chain lengths greater than four are oxidized rapidly with Km values decreasing with increasing carbon chain length. Taken jointly, the composition, structure, and enzymatic properties of the ADH isozymes purified and studied so far strongly imply that their metabolic roles, yet to be discovered, will give a new perspective to ethanol metabolism and pathology.

Efficacy of methylprednisolone in acute spinal cord injury

A multicenter double-blind randomized trial was conducted to examine the efficacy of a high dose of methylprednisolone (1,000-mg bolus and daily thereafter for ten days) compared with a standard dose (100-mg bolus and daily thereafter for ten days) in 330 patients with acute spinal cord injury. No difference in neurological recovery of motor function or pinprick and light touch sensation was observed between the two treatment groups six weeks and six months after injury. The lack of a treatment effect was independent of the severity of the initial lesion or the time from injury to starting treatment. Although not statistically significant, early case fatality was greater in the high-dose protocol (relative risk of 3.1 and 1.9, less than or equal to 14 and 15 to 28 days after injury, respectively) but not from 29 to 210 days after injury. Wound infections of both trauma and operative sites were more prevalent in the high-dose regimen (relative risk of 3.6).

Prediction of leg viability and amputation level by fluorescein uptake

There is a continuous search for more reliable, locally non-invasive tests for prediction of leg viability and for the selection of amputation levels in dysvascular lower limbs. Refinement of the dermofluorometer by addition of a shielded probe and fibreoptic bundles has reduced the bulk of the instrument and permitted rapid testing. Excitation light is carried to the tissues and emitted fluorescence is returned to a photo multiplier. The Index of Fluorescein Uptake is 20-30 units in control areas. Healing is constant above 15 units, inconstant from 5 to 15 units, and absent below 5 units. Reliability has been virtually 10% in preliminary tests.

An index to measure the healing potential of ischaemic ulcers using Thallium 201

Prediction of healing of ulcers in ischaemic limbs can preclude unnecessary treatment for ulcers that cannot heal. Non-invasive methods are of marked value as the ischaemic limb is susceptible to further ulceration from local skin penetration. Relative hyperemia of the ulcer was measured by scintillation count over the ulcer and at points 2.5 cm from the edge of the ulcer. Relative hyperemia was determined by dividing the count per unit area of the ulcer by the counts per unit area of the surrounding tissue. All ulcers with a relative hyperemia over 1.5 healed.

One hundred fold increased activity of Aeromonas aminopeptidase by sequential substitutions with Ni(II) or Cu(II) followed by zinc

Full substitution of Cu(II) or Ni(II) for the two g-atom zinc in Aeromonas aminopeptidase hyperactivates the enzyme 6.5 and 25 fold respectively. Even greater enhancements of activity can be achieved with mixed metal substitutions. Thus, apoenzyme reactivated by first adding one g-atom zinc followed by one g-atom of either Cu(II) or Ni(II) is 15 and 22 times more active than the native enzyme. Reversing the order, i.e. by first adding either one g-atom Cu(II) or Ni(II) followed by one g-atom zinc, activates the enzyme nearly 100 fold. The order of metal addition is critical and suggests the existence of two non-identical metal sites, each with a different function.

Ambulation levels of bilateral lower-extremity amputees. Analysis of one hundred and three cases

One hundred and three bilateral lower-extremity amputees were evaluated to determine their eventual ambulation level. Of thirty-eight bilateral above-the-knee amputees, two with traumatic amputation were prosthetically rehabilitated, while none of the thirty-five with dysvascular amputation were so rehabilitated. Twenty-two of the dysvascular above-the-knee amputees were wheelchair ambulators and thirteen were bedridden. Prosthetic rehabilitation has been successful for traumatic bilateral above-the-knee amputees but has never been successful for our dysvascular bilateral above-the-knee amputees. The goal for dysvascular bilateral above-the-knee amputees is wheelchair ambulation. Of twenty-one patients with combinations of above-the-knee and below-the-knee amputations, five were prosthetically rehabilitated, including four dysvascular amputees; ten were wheelchair ambulators; and six were bedridden. Of forty-four patients with bilateral below-the-knee amputation, thirty-five were prosthetically rehabilitated and the remaining nine were wheelchair ambulators. Since the success rate for prosthetic rehabilitation is higher for amputees with combination above-the-knee and below-the-knee amputation than for those with bilateral above-the-knee amputation, and again increases for those with bilateral below-the-knee amputation, the significance of preserving the knee joint, even a single knee, cannot be overemphasized.

Kinetic properties of human liver alcohol dehydrogenase: oxidation of alcohols by class I isoenzymes

Class I isoenzymes of alcohol dehydrogenase (ADH) were isolated by chromatography of human liver homogenates on DEAE-cellulose, 4-[3-[N-(6-aminocaproyl)-amino]propyl]pyrazole--Sepharose and CM-cellulose. Eight isoenzymes of different subunit composition (alpha gamma 2, gamma 2 gamma 2, alpha gamma 1, alpha beta 1, beta 1 gamma 2, gamma 1 gamma 1, beta 1 gamma 1, and beta 1 beta 1) were purified, and their activities were measured at pH 10.0 by using ethanol, ethylene glycol, methanol, benzyl alcohol, octanol, cyclohexanol, and 16-hydroxyhexadecanoic acid as substrates. Values of Km and kcat for all the isoenzymes, except beta 1 beta 1-ADH, were similar for the oxidation of ethanol but varied markedly for other alcohols. The kcat values for beta 1 beta 1-ADH were invariant (approximately 10 min-1) and much lower (5-15-fold) than those for any other class I isoenzyme studied. Km values for methanol and ethylene glycol were from 5- to 100-fold greater than those for ethanol, depending on the isoenzyme, while those for benzyl alcohol, octanol, and 16-hydroxyhexadecanoic acid were usually 100-1000-fold lower than those for ethanol. The homodimer beta 1 beta 1 had the lowest kcat/Km value for all alcohols studied except methanol and ethylene glycol; kcat values were relatively constant for all isoenzymes acting on all alcohols, and, hence, specificity was manifested principally in the value of Km. Values of Km and kcat/Km revealed for all enzymes examined that the short chain alcohols are the poorest while alcohols with bulky substituents are much better substrates. The experimental values of the kinetic parameters for heterodimers deviate from the calculated average of those of their parent homodimers and, hence, cannot be predicted from the behavior of the latter. Thus, the specificities of both the hetero- and homodimeric isoenzymes of ADH toward a given substrate are characteristics of each. Ethanol proved to be one of the "poorest" substrates examined for all class I isoenzymes which are the predominant forms of the human enzyme. On the basis of kinetic criteria, none of the isoenzymes of class I studied oxidized ethanol in a manner that would indicate an enzymatic preference for that alcohol.

Proteolytic Activity in Soybean Root Nodules : Activity in Host Cell Cytosol and Bacteroids throughout Physiological Development and Senescence

Root nodules were harvested from chamber-grown soybean (Glycine max L. Merrill cv Woodworth) plants throughout development. Apparent nitrogenase activity (acetylene reduction) peaked before seeds began to develop, but a significant amount of activity remained as the seeds matured. Nodule senescence was defined as the period in which residual nitrogenase activity was lost. During this time, soluble protein and leghemoglobin levels in the host cell cytosol decreased, and proteolytic activity against azocasein increased. Degradative changes were not detected in bacteroids during nodule senescence. Total soluble bacteroid protein per gram of nodule remained constant, and an increase in proteolytic activity in bacteroid extracts was not observed. These results are consistent with the view that soybean nodule bacteroids are capable of redifferentiation into free-living bacteria upon deterioration of the legume-rhizobia symbiosis.

Reversible dark-induced senescence of soybean root nodules

Nodule senescence was induced in intact soybean [Glycine max. (L.) Merr., cv Woodworth] plants by an 8-day dark treatment. Dark-induced senescence resulted in the complete loss of acetylene reduction activity, a 67% loss of total soluble protein, and an almost complete loss in total leghemoglobin of nodule extracts. Isoelectric focusing gels demonstrated a preferential loss of certain proteins, which was correlated with an increase in endoprotease specific activity toward azocasein. Nodules were completely green after the 8-day dark treatment. If plants were returned to a normal photoperiod after 8 days in the dark, nodules recovered from the dark treatment in 12 to 16 days. Acetylene reduction activity returned to normal, and both total soluble protein and leghemoglobin were resynthesized while protease activity against azocasein decreased to the level of control nodules. The nodule population that had turned green after 8 days in the dark exhibited a progressive increase in red color starting nearest the exterior of the nodule, and after 16 days of recovery nodules were indistinguishable from control nodules maintained under a normal photoperiod.

Ankle fusion for degenerative arthritis secondary to the collagen diseases

This study reviews the arthritis clinic population of Rancho Los Amigos and a private practice limited to foot and ankle to determine the number of ankle fusions performed for collagen diseases. Rheumatoid arthritis was found to be the most common disease with ankle involvement severe enough to require fusion. From 8020 clinic visits in a 2-year period there were 61 total hip replacements, 56 total knee replacements, and no total ankle replacements. Three ankle fusions were performed. In a private practice out of 90 patients seen for ankles painful enough to require fusion, 6 were in rheumatoid arthritics. A successful ankle fusion was compatible with good function of the lower limb. Motion lost through fusion could be restored with a rocker-bottom shoe. Significant complications occurred with ankle fusion.

Peptidohydrolases of Soybean Root Nodules : IDENTIFICATION, SEPARATION, AND PARTIAL CHARACTERIZATION OF ENZYMES FROM BACTEROID-FREE EXTRACTS

Nodule extracts prepared from Glycine max var Woodworth possessed endopeptidase, aminopeptidase, and carboxypeptidase activities. Three distinct endopeptidase activities could be resolved by disc-gel electrophoresis at pH 8.8. According to their order of increasing electrophoretic mobility, the first of these enzymes hydrolyzed azocasein and n-benzoyl-l-Leu-beta-naphthylamide, while the second hydrolyzed n-benzoyl-l-Arg-beta-naphthylamine (Bz-l-Arg-betaNA), n-benzoyl-l-Arg-p-nitroanilide (Bz-l-Arg-pNA), and azocasein. The third endopeptidase hydrolyzed Bz-l-Arg-betaNA, Bz-l-Arg-pNA, and hemoglobin. Fractions of these enzymes extracted from electrophoresis gels were shown to have pH optima from 7.5 to 9.8. All of the endopeptidases were completely inhibited by diisopropylphosphorofluoridate, demonstrating that they were serine proteases.Aminopeptidase activity was measured using amino acyl-beta-naphthylamides. Electrophoresis of nodule extracts at pH 6.8 resolved the aminopeptidase activity of nodule extracts into at least four fractions based on mobility and on activities toward amino acyl-beta-naphthylamides. The major activity of two of the aminopeptidases was directed toward l-Leu- and l-Met-beta-naphthylamide, while the other two aminopeptidases exhibited broader specificity and were capable of hydrolyzing a large number of amino acyl-beta-naphthylamides. Two of the aminopeptidases extracted from electrophoresis gels were classified as thiol type enzymes, and all four aminopeptidases had neutral to basic pH optima.

Purification and characterization of multiplication-stimulating activity (MSA) carrier protein

The rat liver cell line, BRL-3A, is known to produce a family of polypeptides referred to as multiplication-stimulating-activity (MSA). Serum-free conditioned medium from this cell line is a rich source for the purification of these somatomedin-like molecules. Somatomedins in serum, as well as MSA produced by BRL-3A cells in culture, exist primarily as a high molecular weight complex bound to specific carrier proteins. This study describes the purification of the MSA carrier protein (MCP) from conditioned medium using affinity chromatographic procedures. The purified carrier protein is shown to specifically bind labeled MSA and generates a complex with an apparent molecular weight of 60,000-70,000 daltons. Characterization of the carrier protein indicates that it consists of two different noncovalently linked protein chains with apparent molecular weights of 30,000 and 31,500 daltons. The availability of a pure carrier protein should provide a unique opportunity to investigate the functional significance of the carrier protein in the biological activity of the somatomedins.

Partial and total calcanectomy: a review of thirty-one consecutive cases over a ten-year period

From 1968 to 1978 we performed twenty partial and eleven total calcanectomies in twenty-nine patients, eighteen of whom were diabetics with ulcerations of the heel. All but two had osteomyelitis of the calcaneus. Eight of the patients had an injury of the spine. The remaining patients had conditions in which sensation in the heel was absent or decreased. In about one-half of the diabetic patients, immediate failure of the procedure led to amputation. Primary wound-healing occurred in only four of the eighteen diabetics, but in the non-diabetic patients ten of the thirteen heels showed primary healing. Late failure also occurred in three diabetic patients. The overall rate of failure in the diabetics was 65%.

Quantitative aerobic and anaerobic bacteriology of infected diabetic feet

Quantitative aerobic and anaerobic cultures of deep tissue were performed on amputated infected lower limbs of 13 diabetic patients immediately after surgery. Dissection was made through intact skin distant from any preexisting ulcer. The results were compared with those obtained from: (i) ulcer swabs (pre- and postamputation), (iii) curettage of the ulcer base, and (iii) needle aspiration after normal saline injection. Anaerobic transport media were used for anaerobic cultures before prompt transfer to the anaerobic chamber. A mean of 4.7 bacterial species per specimen was seen (2.3 aerobes, 2.4 anaerobes). Mean log10 growth per gram of tissue was as follows: (i) aerobes plus anaerobes = 6.99, (ii) aerobes = 6.42, and (iii) anaerobes = 7.65. There was poor concordance between the deep tissue culture results and the results from other modalities of culture collection, though the results from other modalities of culture collection, though the results from curettage and saline aspiration were slightly better than those obtained from ulcer swabs. The most frequently isolated organisms were enterococci, anaerobic streptococci, and species of Proteus, Clostridium, and Bacteroides. When anti-microbial therapy is indicated for this patient population, the possibility of the concomitant presence of aerobes as well as anaerobes should be considered.

Microbiology of superficial and deep tissues in infected diabetic gangrene

In the current study, it is shown that, in the lesions of diabetic gangrene, there are usually mixed flora of two or more organisms. The organisms isolated from the presenting lesion may only partially reflect the organisms found in the deep tissues. Of the 58 cultures from the deep tissues, 11 of the isolates were anaerobes, but those anaerobes were never isolated as a pure culture. Bacterial synergism probably plays a role in infected diabetic gangrene. Maximizing the reduction of systemic infection and local cellulitis by elevation and appropriate antibiotic therapy results in improved wound healing in amputations of the lower extremities in patients with diabetic gangrene. However, apparent from this study, antibiotic therapy does not eradicate the organisms in the deep tissue, and surgical procedures are usually required for definitive treatment. Material from the surgically removed infected tissue should always be cultured for identification of existing organisms. When indicated, appropriate adjustment of antibiotic therapy, based upon these findings, should be prescribed.

Transcutaneous Doppler ultrasound in the prediction of healing and the selection of surgical level for dysvascular lesions of the toes and forefoot

Dysvascular lesions of the toes and forefoot are divided into 5 grades and matched with appropriate treatment programs. Patients with diabetes mellitus and arterosclerosis obliterans make up the greatest number presenting with such problems. Transcutaneous Doppler ultrasound has been added to clinical criteria as an aid in the prediction of healing. Systolic blood pressures are taken at the thigh, knee, calf, ankle, foot and toes using transcutaneous Doppler ultrasound as a sensitive stethoscope. Systolic blood pressure taken at the antecubital fossa is divided into the lower extremity pressures to obtain an ischemic index. Healing can be predicted with 90% or better accuracy where the ischemic index is above 0.35 in the arteriosclerotic foot and above 0.45 in the diabetic foot.

Microbiology of deep tissue in diabetic gangrene

Information on the incidence and nature of the causative organisms in the infected tissues of patients with diabetic gangrene is scanty. Studies in which material for culture was obtained from the presenting lesion reveal multiple organisms in host isolates. No data are available regarding the bacterial flora of the deep infected tissue itself, uncontaminated by surface organisms. In this investigation 58 specimens from 52 patients were obtained utilizing aerobic and anaerobic culture techniques. In the surgical theater, material was obtained from the infected deep tissues using careful aseptic dissection techniques. All patients had been on antibiotic therapy from 2 to 10 days before the study. An average of 2.3 organisms per specimen was found. The predominant organisms were Proteus sp., Enterococcus, Staphylococcus aureus, and other enterobacteriacae in that order. Anaerobes were isolated in 27 per cent of cases, but never as the only organism. Prior antibiotic therapy did not eradicate infection in infected diabetic gangrene.