Biomedical subjects
Publications and source records attributed to R E McCarthy.
Bilateral avulsion fracture of the tibial tuberosity is a rare injury. A 14-year-old male gymnast sustained simultaneous tibial tuberosity displaced fractures while attempting a forward flip. The recommended treatment was open reduction and internal fixation. Functional results were excellent one year after surgical treatment.
The focus of medicine has increasingly turned toward prevention rather than treatment of disease. In the absence of the ability to prevent the occurrence of scoliosis, the focus of attention should be on early identification in order to prevent complications brought on by the disease. Scoliosis detection through screening of school children is a technique that has been popularized over the last three decades. The screening technique can be performed by trained personnel. Though the initial result of these screenings was over-diagnosis, the program has been shown to be cost-effective when the screeners are well-trained and appropriate referrals are made to minimize the lack of specificity. The use of the scoliometer to make a quantitative determination of the degree of truncal rotation has reduced the number of inappropriate referrals. The complications of scoliosis itself include pulmonary compromise, pain, and deformity; these are best prevented by early detection and early treatment. When scoliosis is treated late and larger curves are present, more involved and complication-ridden procedures are required. School children screening programs promote a better understanding and heightened awareness of this disease and acceptance of the treatment methods by the public.
Four neonates presented with leg-length discrepancy in the first and second year of life, secondary to physeal growth arrest. All four had stormy postnatal periods, requiring indwelling arterial and/or hyperalimentation catheters. One had documented osteomyelitis. In the last three cases, the growth disturbance may have been secondary to aseptic emboli to the bones from the indwelling catheters. In two cases, there was evidence of other nonseptic embolic phenomena.
Five Bacteroides species that are found in the human colon can utilize polygalacturonic acid (PGA) when they are grown in laboratory media: Bacteroides thetaiotaomicron, Bacteroides vulgatus, Bacteroides ovatus, Bacteroides fragilis subsp. a, and Bacteroides sp. strain 3452A (an unnamed DNA-DNA homology group). PGA-degrading enzymes from B. thetaiotaomicron have been isolated and characterized previously. To determine whether a PGA lyase activity in human feces could be attributed to any of these species, we first determined the properties of PGA lyases from the other four Bacteroides species. PGA lyases from all the Bacteroides species were soluble, cell associated, and inducible by PGA. All had similar pH optima (8.4 to 8.8) and similar molecular weights (50,000). All activities were enhanced by calcium. The PGA lyases from the five species differed with respect to isoelectric point: B. thetaiotaomicron (pI 7.5), B. vulgatus (pI 7.7), B. ovatus (pI 5.8, 7.2), B. fragilis subsp. a (pI 6.1), and Bacteroides sp. strain 3452A (pI 7.7). The PGA lyase activity in human feces resembled those of the Bacteroides PGA lyases in that it had a pH optimum of 8.4 to 8.8 and was enhanced by calcium. However, it differed from the Bacteroides PGA lyases both with respect to isoelectric point (pI 4.2 to 4.4) and molecular weight (100,000). On the basis of these findings, it appears that the PGA lyase activity in human feces is not produced by any of the Bacteroides species surveyed in this survey. Moreover, there was no detectable PGA lyase activity in feces that had the same properties as the Bacteroides enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
To determine the efficacy of allograft bone in spinal surgery, a retrospective study was carried out on thirty-two patients who had had spinal fusion with banked bone from the femoral head between 1977 and 1983. The diagnoses were paralytic and neuromuscular scoliosis. At final follow-up (average, 3.7 years), the infection rate was 9.3 per cent. There were no pseudarthroses, and all patients had well marginated trabecular markings by eighteen months. The rates of complications and of fusion were comparable with or better than those obtained using autogenous bone graft.
We report the cases of five children, six to eighteen months old, who had bilateral fracture of the pedicles of the second cervical vertebra. The children were treated with gentle cervical traction in mild extension or were maintained in near-anatomical reduction in a Minerva jacket or halo cast. The fractures united in four patients. One patient underwent fusion to stabilize the spine.
Timentin, a combination of clavulanic acid (0.1 g) and ticarcillin (3.0 g), has proved effective in vitro against bacterial pathogens that produce beta-lactamases. The usual etiologic bacteria of osteochondritis of the foot (Pseudomonas species) and osteomyelitis/septic arthritis (Staphylococcus aureus) are commonly resistant to penicillins. To date, we have used Timentin to treat 30 children with bone, joint, and deep soft tissue infections. Timentin was administered intravenously at an average dosage of 207 mg/kg per day for mild to moderate infection and 310 mg/kg per day for bone and joint infections with systemic signs (sepsis). The lower dose was used in 24 patients and the other six patients, who had signs of sepsis, received the higher dose. All patients received Timentin intravenously over 30 minutes every four to six hours for a minimum of five days (mean 6.6 +/- 2.6 days, range five to 14 days). The mean time to defervescence and/or reduction in clinical symptoms was 1.6 +/- 1.3 days (range zero to four days). Osteochondritis due to P. aeruginosa was diagnosed in six patients, and septic bursitis, osteomyelitis, or septic arthritis due to S. aureus (13 patients) or Staphylococcus species and group A streptococci (four patients) was diagnosed in 17 patients. All isolates were susceptible to Timentin in vitro by disk-diffusion analysis. All patients showed a response to therapy with Timentin, with or without surgical intervention. All patients had clinical and microbiologic cures; no adverse reactions or side effects were observed. There have been no clinical or microbiologic relapses to date. Timentin may prove to be useful in specific bone and joint infections in children.
When Bacteroides thetaiotaomicron is grown in medium which contains polygalacturonic acid (PGA) as the sole carbon source, two different polygalacturonases are produced: a PGA lyase (EC 4.2.2.2) and a PGA hydrolase (EC 3.2.1.15). Both enzymes are cell associated. The PGA hydrolase appears to be an inner membrane protein. The PGA lyase is a soluble protein that associates with membranes under certain conditions. The PGA lyase was purified to apparent homogeneity. It has a molecular weight (from sodium dodecyl sulfate-polyacrylamide gel electrophoresis) of 74,000, a pH optimum of 8.7, a pI of 7.5, and a Km for PGA of 40 to 70 micrograms/ml. It requires calcium for maximal activity. The main product of this enzyme appears to be a disaccharide that contains a delta 4,5-unsaturated galacturonic acid residue. The PGA hydrolase can be solubilized from membranes with 2% Triton X-100 and has been partially purified. It has a pH optimum of 5.4 to 5.5, a pI of 4.7 to 4.9, and a Km for PGA of 350 to 400 micrograms/ml. The main product of this enzyme appears to be galacturonic acid. The specific activities of both PGA hydrolase and PGA lyase increase at the same rate when bacteria are exposed to PGA. The two enzymes therefore appear to be similarly regulated.
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Twenty-six children with fractures of the femur were entered into a prospective study to determine the efficacy of treating certain of these fractures by early spica cast immobilization. They were compared with 50 consecutive patients with similar fractures who were treated prior to the study to determine the potential cost savings and decrease in patient days in hospital. The clinical results of treatment were compared with results from the literature and the previous group where applicable. Our conclusion from this study is that most femoral shaft fractures in children under 10 years of age can be treated by closed reduction and early spica cast immobilization with results that are at least as good as those achieved by conventional methods, and with a 70% savings in hospital cost. Factors such as obesity, swelling, shortening, comminution, and fracture type can all combine to give relative contraindications for the use of this technique.
This retrospective analysis of 406 patients with proximal femoral fractures was designed to identify both the significant and nonsignificant risk factors that influence patient mortality. The 399 patients treated by open reduction and internal fixation or femoral head prostheses routinely received prophylactic antibiotics and anticoagulants. Of 406 patients followed until death or for at least one year, the overall mortality rate at one year was 14% (58/406). For patients with subcapital fractures the rate was 13% (25/187) and with intertrochanteric fractures 15% (33/219). The expected mortality rate for the normal population of similar age was about 9%. Sex, treatment of subcapital fracture by either internal fixation or arthroplasty, and the level of postoperative ambulation did not influence mortality. The number of preexisting medical conditions and the time of surgery following admission were highly significant factors (p less than or equal to 0.001 for both). The number of postoperative medical complications was also significant. The recommendation is for serious medical conditions to be maximally stabilized for at least 24 hours and pulmonary and physical therapy instituted before scheduling open surgical procedures.
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The indications for amputation with pseudarthrosis of the tibia are: failure of bony union after three surgical attempts; significant leg-length discrepancy; interference with growth distal to the pseudarthrosis; and a significant period under medical care, such that the patient suffers unduly. The primary problems related to amputating at the level of the pseudarthrosis are poor stump configuration, bony overgrowth, and poor skin coverage. A distal amputation at the ankle is recommended, using the technique for a cartilage-preserving Symes amputation. Methods for realigning the tibia at the time of amputation include the use of an intermedullary rod or a compression plate. The ultimate goal of treatment is always a functional limb.
A 17-year-old boy, who had complained of pain for many years, had an anomalous branch from the dorsal ulnar cutaneous nerve which passed ulnar to the pisiform bone and was compressed by the flexor carpi ulnaris tendon. The symptoms were relieved completely by decompression of this nerve.
The effect of high mol. wt dextran sulphate (DS) on two different indicators of the cell-mediated immune response was studied simultaneously in the same animal. The two indicators of the cell-meidated immune response chosen for this study were the footpad swelling response to sheep red blood cells (SRBC) and skin allograft rejection. Mice receiving DS and SRBC showed a significant increase in the delayed-type footpad swelling response over the controls at 24 and 48 h after challenge, while in addition, the same mice showed a significant suppression of the delayed-type response to allograft antigens as indicated by a significant delay in rejection time of allografts. The results presented here show that DS is capable of simultaneously stimulating and suppressing two indicators of the cell-mediated immune response in the same animal.
The effect of high mol. wt dextran sulphate (DS) on cell-mediated immune responses was studied. Three criteria were used to assess cell-mediated delayed-type hypersensitivity: footpad swelling, i.d. skin tests and macrophage migration inhibitory factor (MIF) production. Guinea-pigs sensitized with egg albumin (EA) and treated with DS showed strong positive delayed skin tests. Control animals given only EA showed negative skin tests. Lymphocytes from mice sensitized s.c. with EA and treated with DS showed an increase in MIF production. Delayed footpad swelling responses in mice sensitized s.c. with sheep red blood cells (SRBC) and treated with DS were increased when the mice were challenged 8 days after sensitization. Doses of DS which were effective in increasing delayed footpad swelling ranged from 50-200 mg DS/kg body weight. DS was only capable of increasing delayed footpad swelling responses when both SRBC and DS were injected s.c. at the same site. Intraperitoneal injection of both SRBC and DS obeebction of both s.c. but at different sites did not result in increased delayed footpad swelling. DS was capable of augmenting footpad swelling responses when given s.c. as much as 6 days before SRBC. The optimal time for administration of DS was 2 days before SRBC. Injection of DS 2 days or more after SRBC resulted in no increase in delayed footpad swelling responses. The results of this study indicate that dextran sulphate is a potent adjuvant for cell-mediated delayed-type hypersensitivity immune responses in both mice and guinea-pigs.