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Biomedical subjects

K Katz

Publications and source records attributed to K Katz.

At least 19 recordsLinked to original sources

Immobilisation of forearm fractures in children: extended versus flexed elbow.

Redisplacement of unstable forearm fractures in plaster is common and may be the result of a number of factors. Little attention has been paid to the influence of immobilisation with the elbow extended versus flexed. We prospectively treated 111 consecutive children from two centres with closed forearm fractures by closed reduction and casting with the elbow either extended (60) in China or flexed (51) in Israel. We compared the outcome of the two groups. There was no statistically significant difference in the distribution of the age of the patients, the site of fracture or the amount of angulation and displacement between the groups. During the first two weeks after reduction, redisplacement occurred in no child immobilised with the elbow extended and nine of 51 children (17.6%) immobilised with the elbow flexed. Immobilisation of unstable forearm fractures with the elbow extended appears to be a safe and effective method of maintaining reduction.

Casts, Surgical↗

Prenatal ultrasound diagnosis of club foot: outcome and recommendations for counselling and follow-up.

Club foot was diagnosed by ultrasonography in 91 feet (52 fetuses) at a mean gestational age of 22.1 weeks (14 to 35.6). Outcome was obtained by chart review in 26 women or telephone interview in 26. Feet were classified as normal, positional deformity, isolated club foot or complex club foot. At initial diagnosis, 69 feet (40 fetuses) were classified as isolated club foot and 22 feet (12 fetuses) as complex club foot. The diagnosis was changed after follow-up ultrasound scan in 13 fetuses (25%), and the final ultrasound diagnosis was normal in one fetus, isolated club foot in 31 fetuses, and complex club foot in 20 fetuses. At birth, club foot was found in 79 feet in 43 infants for a positive predictive value of 83%. Accuracy of the specific diagnosis of isolated club foot or complex club foot was lower; 63% at the initial ultrasound scan and 73% at the final scan. The difference in diagnostic accuracy between isolated and complex club foot was not statistically significant. In no case was postnatal complex club foot undiagnosed on fetal ultrasound and all inaccuracies were overdiagnoses. Karyotyping was performed in 25 cases. Abnormalities were noted in three fetuses, all with complex club foot and with additional findings on ultrasound.

Clubfoot↗

Monitoring of the sciatic nerve during hamstring lengthening by evoked EMG.

Traction injury to the sciatic nerve can occur during hamstring lengthening. The aim of this study was to monitor the influence of hamstring lengthening on conduction in the sciatic nerve using evoked electromyography (EMG). Ten children with spastic cerebral palsy underwent bilateral distal hamstring lengthening. Before lengthening, the evoked potential was recorded with the patient prone. During lengthening, it was recorded with the knee flexed to 90 degrees, 60 degrees and 30 degrees, and at the end of lengthening with the hip and knee extended. In all patients, the amplitude of the evoked EMG gradually decreased with increasing lengthening. The mean decrease with the knee flexed to 60 degrees was 34% (10 to 77), and to 30 degrees, 86% (52 to 98) compared with the pre-lengthening amplitude. On hip extension at the end of the lengthening procedure, the EMG returned to the pre-lengthening level. Monitoring of the evoked EMG potential of the sciatic nerve during and after hamstring lengthening, may be helpful in preventing traction injury.

Adolescent↗

Congenital insensitivity to pain. Orthopaedic manifestations.

We reviewed 13 patients with congenital insensitivity to pain. A quantitative sweat test was carried out in five and an intradermal histamine test in ten. DNA examination showed specific mutations in four patients. There were three clinical presentations: type A, in which multiple infections occurred (five patients); type B, with fractures, growth disturbances and avascular necrosis (three patients); and type C, with Charcot arthropathies and joint dislocations, as well as fractures and infections (five patients, four with mental retardation). Patient education, shoeware and periods of non-weight-bearing are important in the prevention and early treatment of decubitus ulcers. The differentiation between fractures and infections should be based on aspiration and cultures to prevent unnecessary surgery. Established infections should be treated by wide surgical debridement. Deformities can be managed by corrective osteotomies, and shortening by shoe raises or epiphysiodesis. Joint dislocations are best treated conservatively.

Adolescent↗

Anxiety reaction in children during removal of their plaster cast with a saw.

We have had experience of an 18-month-old boy with a cardiomyopathy who died a few minutes after removal of his cast with a saw, apparently from a malignant cardiac arrhythmia triggered by anxiety. We therefore examined the anxiety reaction to this method of removal of a plaster cast in 20 healthy children; ten were provided with hearing protectors and ten were not. The level of anxiety was assessed by measuring the heart rate, a known physiological indicator of anxiety, before, during and five minutes after removal of the cast. The noise level was also measured. The results showed a mean increase in heart rate during the procedure of 27.9 beats per minute (bpm) (26.9%) in the children with no hearing protectors and 10.4 bpm (11.1%) in children who used hearing protectors (p < 0.001). Five minutes after the procedure the heart rate had returned to the baseline rate in all patients. We recommend that hearing protectors should be used in children undergoing removal of a plaster cast to decrease the anxiety reaction. If possible, clinicians should avoid the use of a saw for this purpose in children with a cardiomyopathy.

Anxiety↗

Effects of amoxicillin/clavulanate or azithromycin on nasopharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae in children with acute otitis media.

The effect of antibiotic therapy on nasopharyngeal colonization by Streptococcus pneumoniae and Haemophilus influenzae was evaluated in children diagnosed with acute otitis media. Children were randomly assigned to receive either amoxicillin/clavulanate or azithromycin therapy, and nasopharyngeal swabs were obtained for culture before and after starting therapy. Amoxicillin/clavulanate therapy eradicated or suppressed all strains of S. pneumoniae susceptible to penicillin, 75% of strains with intermediate resistance, and 40% of strains resistant to penicillin. Azithromycin therapy cleared two-thirds of azithromycin-susceptible strains of S. pneumoniae but none of azithromycin-nonsusceptible strains. Selection for antibiotic-resistant strains in individual children was not observed in children who received amoxicillin/clavulanate therapy but was observed in 2 children who received azithromycin therapy. Carriage of H. influenzae was also reduced by antimicrobial therapy but more so by amoxicillin/clavulanate. Antibiotic therapy does not directly increase the number of resistant strains in the population but, by eradicating susceptible strains, allows greater opportunity for carriage and spread of resistant strains.

Acute Disease↗

Vasopressin pressor effects in critically ill children during evaluation for brain death and organ recovery.

BACKGROUND: Vasopressin (VP) shows promise as a pressor agent in animals and adult human cardiac arrest and resuscitation, but has not been studied for pressor effect in critically ill or arrested children. VP infusion is routine treatment for diabetes insipidus during brain death evaluation and organ recovery. We hypothesized that low dose VP infusion during organ recovery in critically ill children exerts a pressor effect, without major organ toxicity. METHODS: 34 VP-treated and 29 age-matched critically ill controls (C) < or =18 years were retrospectively reviewed during brain death evaluation and organ recovery. VP infusion protocol titrated VP dose clinically to urine output, with high variability. Pressor and inotrope management was titrated clinically to BP, cerebral perfusion and central venous pressures (when available) and peripheral perfusion with similar protocol targets for pre-load in VP and C groups. Outcome measures include dose, type and number of pressors and inotropes. Organ function was assessed at recovery and 48 h post-transplant by independent surgeon and transplant program organ function criteria. Analysis by Odds Ratio (OR), and chi-square. RESULTS: VP dose averaged 0.041+/-0.069 U/kg/h. Average baseline mean arterial pressure (MAP) before VP infusion was 79+/-17 mmHg VP and 76+/-14 mm Hg C (P=0.6). Subsequent average MAP were: 82+/-21 mmHgVP after VP infusion versus 71+/-16 mmHg C (P=0.01) and 80+/-14 mmHg VP versus 68+/-22 mmHg C (P=0.01). Ability to wean/stop pressors and inotropes was: dopamine (14/23) 42% VP versus (10/26) 38% C (P=0.75), dobutamine (4/7) 57% VP versus (0/6) 0% C (P=0.026), epinephrine (4/5) 80% VP versus (0/6) 0% C (P=0.006), norepinephrine/phenylephrine (4/4) 100% VP versus (2/5) 40% C (P=0. 057). Alpha agonist pressor dependence was successfully weaned from 7/9 (78%) VP versus 0/9 (0%) C: odds ratio=7.3, (P<0.01). There was no VP induced dysrhythmia, hypertension, anuria or toxicity reported. Good organ recovery function was not significantly different at recovery or 48 h post-transplant for kidney (79% VP versus 69% C, P=0.068), liver (87% VP versus 95% C, P=0.533), or heart (90% VP versus 71% C, P=0.11). CONCLUSIONS: Low dose vasopressin infusion exerts a pressor effect in critically ill children treated for diabetes insipidus during brain death and organ recovery. VP treated patients were 7.3 times more likely to wean from alpha agonists than comparably managed age matched controls, without adverse affect on transplant organ function. We speculate that further prospective assessment of VP safety and efficacy as a pressor adjunct for resuscitation of critically ill children is warranted.

Adolescent↗

Early mobilization after sliding achilles tendon lengthening in children with spastic cerebral palsy.

Equinus deformity is a common finding in children with cerebral palsy and may be treated by Achilles tendon lengthening. To prevent recurrence, some authors recommend immobilizing the operated leg with an above-knee cast for six weeks, followed by use of a night splint or orthosis. Nevertheless, there are recurrence rates of up to 20.5%. The aim of this study was to evaluate the long-term result of postoperative immobilization for two weeks in a below-knee cast and early weight bearing, without the use of a splint or orthosis. Thirty-six children (52 feet) with spastic cerebral palsy underwent sliding Achilles tendon lengthening. Follow-up of five to ten years showed a comparable recurrence rate (19.2%) to that reported with the standard, more stringent management approach. Most of the recurrences were in children operated on before five years of age. We believe earlier motion helps to sustain the tendon length achieved at surgery and allows for earlier independent gait.

Achilles Tendon↗

Osteoid osteoma: resection with CT guidance.

BACKGROUND: Osteoid osteoma is a benign bone lesion characterized by nocturnal pain mostly, which may be relieved by non-steroidal prostaglandin inhibitors. Treatment by complete resection of the nidus immediately relieves the pain. Intraoperative location of the nidus may be difficult, and extensive bone resection may be necessary to ensure complete excision. Few studies have described resection of osteoid osteoma under CT guidance, and little attention has been given to lesions near the neurovascular bundle. OBJECTIVE: To report our results of osteoid osteoma resection under CT guidance, with specific attention to lesions lying near the neural structure. METHODS: Nine patients with suspected osteoid osteoma underwent resection with a 6.8 mm core drill under CT guidance. RESULTS: Histologic confirmation was obtained in seven patients, while in two there was no evidence of the nidus in the excised bone material. All nine reported complete pain relief immediately after the surgery. Postoperative CT scan showed complete removal of the osteoid osteoma. CONCLUSIONS: Removal of osteoid osteoma under CT guidance is simple, safe and allows complete removal of the nidus with low morbidity.

Adolescent↗

Orthopaedic manifestations of familial dysautonomia. A review of one hundred and thirty-six patients.

BACKGROUND: Familial dysautonomia is a hereditary multisystemic disease primarily affecting people of Ashkenazi Jewish descent. Musculoskeletal problems are related to gait disorders, spinal deformities, foot deformities, fractures, and arthropathies. METHODS: The charts and radiographs of 136 patients who ranged in age from three months to forty-six years (mean, sixteen years) were reviewed. Sixty-four patients were available for follow-up examination. RESULTS: Spinal deformity was the most common orthopaedic problem and was diagnosed in seventy-eight patients starting at the age of four years, with a prevalence of 86 percent (forty-eight of fifty-six) by the age of fifteen years. Forty-one (53 percent) of the seventy-eight patients had scoliosis only, thirty-four (44 percent) had kyphoscoliosis, and three (4 percent) had kyphosis only. Bracing was accompanied by emotional, pulmonary, and skin problems, leading to a high rate of noncompliance and progression of the curve. Twenty-four patients had an operation at a mean age of thirteen years (range, five to eighteen years): twenty patients had posterior spinal arthrodesis, and four had combined anterior and posterior arthrodesis. Fifteen patients had a total of nineteen complications, of which seven were systemic and twelve were related to the spinal fixation. Eight patients had revision surgery. At the time of the surgery, scoliosis was corrected from a mean of 55 degrees to a mean of 35 degrees and kyphosis was corrected from a mean of 69 degrees to a mean of 61 degrees. After a mean duration of follow-up of sixty-five months, scoliosis measured 49 degrees (range, 18 to 62 degrees) and kyphosis measured 67 degrees (range, 30 to 115 degrees). Postoperative progression of the deformity was caused by failure of the instrumentation or progression in unfused segments. Walking was delayed in 72 percent (ninety-four) of the 130 patients who were of walking age. All sixty-four of the patients who were examined had an ataxic gait. Foot deformities were found in sixteen patients, six of whom were treated surgically. Two patients had Charcot joints. Fifty-five patients sustained at least one fracture before skeletal maturity, with a mean of 1.5 fractures per patient. All but one of the fractures was treated nonoperatively, and fracture-healing was often accompanied by profuse callus formation. CONCLUSIONS: Spinal deformity is common in patients with familial dysautonomia. Bracing is of questionable benefit, and surgical intervention should be considered once curve progression is well documented. Arthrodesis should be extended as far proximally as possible to prevent junctional kyphosis. Swelling and warmth in a limb should raise suspicion of an undiagnosed fracture.

Adolescent↗

Increased carriage of resistant non-pneumococcal alpha-hemolytic streptococci after antibiotic therapy.

OBJECTIVE: We compared colonization and resistance rates of non-pneumococcal alpha-hemolytic streptococci (AHS) and Streptococcus pneumoniae in children receiving antibiotic therapy for acute otitis media. STUDY DESIGN: Between December 1997 and September 1998, children 6 months to 6 years of age, diagnosed with acute otitis media were randomly assigned to receive amoxicillin/clavulanate (Augmentin) 45 mg/kg/d in 2 divided doses for 10 days or azithromycin (Zithromax), 10 mg/kg, once on the first day, followed by 5 mg/kg daily for 4 days. Nasopharyngeal swabs for culture were obtained before and at 2 weeks and 2 months after the start of therapy. Streptococci were identified by species, and antibiotic susceptibility was determined by the epsilometric test. RESULTS: One hundred six children completed the 2-week follow-up and 2-month follow-up, respectively. The nasopharyngeal carriage rate of non-pneumococcal AHS increased from 14% before treatment to 32% at the 2-week follow-up (P =.02) and was similar in both treatment groups. In contrast, the carriage of S pneumoniae decreased from 51% before therapy to 27% at the 2-week follow-up (P =.002). The carriage of penicillin-resistant AHS strains (minimum inhibitory concentration > 1 microg/mL) increased from 9% before treatment to 26% at 2 weeks and 36% at 2 months. CONCLUSIONS: Amoxicillin/clavulanate and azithromycin therapy resulted in increased isolation of nasopharyngeal non-pneumococcal AHS, many of which were multidrug-resistant, in contrast to a decrease in pneumococcal carriage. This suggests that the competitive balance between these 2 groups of organisms was disturbed as a result of differential antibiotic susceptibility. The importance of drug-resistant AHS as a reservoir for resistance genes for S pneumoniae warrants further investigation.

Amoxicillin-Potassium Clavulanate Combination↗

Involvement of the foot and ankle in patients with Gaucher disease.

Of 48 children with type I Gaucher disease treated at our hospital, 11 had involvement of the foot and ankle that first appeared in adolescence. Follow-up ranged from 3 to 27 years (average, 10 years). We reviewed their clinical and radiographic histories. Patients presented with four types of pain: six (7 events of pain) complained of dull pain defined as nonspecific; seven (11 events) had severe pain caused by bone crisis; two (2 events) had moderate progressive pain caused by pathological fractures; and one had painful swollen ankles caused by degenerative arthritis. Greater awareness of these complications in patients with Gaucher disease will prevent misdiagnosis and lead to early treatment.

Adolescent↗

Prognostic factors in non-metastatic limb osteosarcoma: A 20-year experience of one center.

The purpose of this study was to evaluate the prognostic significance of variables in osteosarcoma. We performed a retrospective analysis of 35 patients with non-metastatic limb osteosarcoma that were treated between 1973 and 1994. The following variables were evaluated: age, sex, ethnic group, tumor histology and primary site, alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) levels at diagnosis, treatment regimen, and the histologic response to treatment. Three variables showed significant correlation with prognosis: i) histologic response to preoperative treatment. Disease-free survival (DFS) was 89% in patients with grade III-IV histologic response after a median follow-up (MFU) of 64 months, 67% in patients with grade II after an MFU of 64 months, the patients with grade I response died within 15 months (p<0.0001); ii) treatment regimen. DFS was 83% after an MFU of 42 months, 62% after an MFU of 82 months, and 30% after an MFU of 177 months in patients treated by the 90's, 80's, and 70's protocols, respectively (p<0.05); iii) corrected ALP (cALP) levels at diagnosis. DFS was 78% after an MFU of 88 months in patients with cALP levels <200, and 32% after an MFU of 56 months in patients with cALP levels >200 (p=0.01). Low ALP levels, good histologic response to preoperative chemotherapy, and the new therapeutic regimen correlated with good prognosis in patients with osteosarcoma.

Adolescent↗

Increased operative bleeding during orthopaedic surgery in patients with type I Gaucher disease and bone involvement.

To aid clinicians in identifying patients with type I Gaucher disease who are at risk of excessive bleeding, we reviewed the coagulation parameters of six affected patients with bone involvement who underwent orthopaedic surgery at two centers, and of 22 patients under treatment at another, seven of whom had total splenectomy. All patients were of Jewish Ashkenazi origin. Among the latter group, prolonged prothrombin time was noted in 81%. Incidence of clotting factor deficiency were as follows: factor XI, 36.3%; V, 31.8%; VIII, 27.2%; IX, 13.6%; and XII, 27.2%. Most of the abnormalities occurred in the non-splenectomized patients. Two of the six orthopaedic surgery patients had excessive intraoperative and postoperative bleeding. One, who underwent spinal decompression had prolonged prothrombin time, and the other, who had total hip replacement, showed a deficiency of factor XI. The second patient's hemoglobin level was maintained with transfusion of fresh frozen plasma during contralateral hip arthroplasty five months later. We suggest that preoperative evaluation of clotting factors and replacement therapy may prevent excessive bleeding in patients with type I Gaucher disease.

Adolescent↗

Specific requirement for CD3epsilon in T cell development.

T cell antigen receptor (TCR) and pre-TCR complexes are composed of clonotypic heterodimers in association with dimers of signal transducing invariant subunits (CD3gamma, -delta, -epsilon, and zeta). The role of individual invariant subunits in T cell development has been investigated by generating gene-specific mutations in mice. Mutation of CD3gamma, -delta, or zeta results in an incomplete block in development, characterized by reduced numbers of mature T cells that express low levels of TCR. In contrast, mature T cells are absent from CD3epsilon-/- mice, and thymocyte development is arrested at the early CD4(-)CD8(-) stage. Although these results suggest that CD3epsilon is essential for pre-TCR and TCR expression/function, their interpretation is complicated by the fact that expression of the CD3gamma and CD3delta genes also is reduced in CD3epsilon-/- mice. Thus, it is unclear whether the phenotype of CD3epsilon-/- mice reflects the collective effects of CD3gamma, -delta, and -epsilon deficiency. By removing the selectable marker (PGK-NEO) from the targeted CD3epsilon gene via Cre/loxP-mediated recombination, we generated mice that lack CD3epsilon yet retain normal expression of the closely linked CD3gamma and CD3delta genes. These (CD3epsilonDelta/Delta) mice exhibited an early arrest in T cell development, similar to that of CD3epsilon-/- mice. Moreover, the developmental defect could be rescued by expression of a CD3epsilon transgene. These results identify an essential role for CD3epsilon in T cell development not shared by the CD3gamma, CD3delta, or zeta-family proteins and provide further evidence that PGK-NEO can influence the expression of genes in its proximity.

Amino Acid Sequence↗

cDNA sequencing and analysis of POV1 (PB39): a novel gene up-regulated in prostate cancer.

We recently identified a novel gene (PB39) (HGMW-approved symbol POV1) whose expression is up-regulated in human prostate cancer using tissue microdissection-based differential display analysis. In the present study we report the full-length sequencing of PB39 cDNA, genomic localization of the PB39 gene, and genomic sequence of the mouse homologue. The full-length human cDNA is 2317 nucleotides in length and contains an open reading frame of 559 amino acids which does not show homology with any reported human genes. The N-terminus contains charged amino acids and a helical loop pattern suggestive of an srp leader sequence for a secreted protein. Fluorescence in situ hybridization using PB39 cDNA as probe mapped the gene to chromosome 11p11.1-p11.2. Comparison of PB39 cDNA sequence with murine sequence available in the public database identified a region of previously sequenced mouse genomic DNA showing 67% amino acid sequence homology with human PB39. Based on alignment and comparison to the human cDNA the mouse genomic sequence suggests there are at least 14 exons in the mouse gene spread over approximately 100 kb of genomic sequence. Further analysis of PB39 expression in human tissues shows the presence of a unique splice variant mRNA that appears to be primarily associated with fetal tissues and tumors. Interestingly, the unique splice variant appears in prostatic intraepithelial neoplasia, a microscopic precursor lesion of prostate cancer. The current data support the hypothesis that PB39 plays a role in the development of human prostate cancer and will be useful in the analysis of the gene product in further human and murine studies.

Amino Acid Sequence↗

Low-dose high-frequency enzyme replacement therapy prevents fractures without complete suppression of painful bone crises in patients with severe juvenile onset type I Gaucher disease.

Patients with type I Gaucher disease often present as adults with a mild disease and with less severe genetic mutations, especially 1226G/1226G (N370S/N370S). Patients presenting as children have an excess of compound heterozygotes of N370S and other mutations, such as 84GG, 1448C (L444P) and IVS2 + 1 in whom bone disease is common. We report our experience with low-dose high-frequency enzyme replacement therapy in such severely affected children. Ten patients (with severe juvenile onset type I Gaucher disease) were treated. Alglucerase (Ceredase) was infused at 30 units/kg/month in 13 fractions/month for more than one year. Bone disease was used as the main criterion for evaluating treatment results. No fractures occurred in spite of the fact that bone crises occurred in four patients after 12 to 24 months of treatment, in two during the third year, and in one during the fifth year. Nonosseous manifestations improved with treatment. The ability of low-dose high frequency alglucerase to prevent fractures in the presence of continuing bone crises was demonstrated.

Adolescent↗