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Biomedical subjects

D M Klein

Publications and source records attributed to D M Klein.

At least 19 recordsLinked to original sources
PubMed2006

In situ long-term monitoring system for radioactive contaminants.

A long-term in situ subsurface instrument for monitoring radioactive contaminant plumes, as an alternative to soil analysis, is described. A portable, laser-based reader optically stimulates luminescence from sensors, each containing an Al2O3:C dosemeter. The sensors, designed for placement at various subsurface locations around a waste site, are allowed to accumulate dose for a predetermined time that is based on the instrument's minimum detectable dose (MDD). The reader is then attached to the sensor by fibre optic cable to read the accumulated dose; an increase above natural background levels indicating the presence of leaked radioactivity. Based on an MDD of 5 microGy, it is shown that the sensor can measure soil concentrations of 1.85 Bq cm(-3) after an exposure time of 50 h for 137Cs and 67 h for 90Sr/90Y. Discrimination between beta and gamma radiation is possible using an end cap placed over one of the two paired sensors, allowing simultaneous measurement of 137Cs and 90Sr/90Y in a mixed field. The monitor system represents a substantial improvement over quarterly soil sampling because of a greatly increased measurement frequency and the ability to perform measurements reproducibly.

Dose-Response Relationship, Radiation↗
PubMed2006

Myelin protein zero mutation His39Pro: hereditary motor and sensory neuropathy with variable onset, hearing loss, restless legs and multiple sclerosis.

BACKGROUND: Mutations of myelin protein zero (MPZ) may cause inherited neuropathy with variable expression. OBJECTIVE: To report phenotypic variability in a large American kindred with MPZ mutation His39Pro. PATIENTS: Genetic testing was performed on 77 family members and 200 controls. Clinical and electrophysiological field study assessments were available for review in 47 family members. RESULTS: His39Pro was found in all 10 individuals prospectively identified with neuropathy. 200 normal controls were without mutation. Symptoms of neuropathy began in adulthood and were slowly progressive except for one acute-onset painful sensory neuropathy. Associated features included premature hearing loss (n = 7), nocturnal restless leg symptoms (n = 8) and multiple sclerosis in one. CONCLUSIONS: MPZ mutation His39Pro may be associated with acute-onset neuropathy, early-onset hearing loss and restless legs. The relationship with multiple sclerosis in the proband remains uncertain.

Adult↗
PubMed2005

SPTLC1 and RAB7 mutation analysis in dominantly inherited and idiopathic sensory neuropathies.

BACKGROUND: The variable clinical features of hereditary sensory and autonomic neuropathy (HSAN I) suggest heterogeneity. Some cases of idiopathic sensory neuropathy could be caused by missense mutations of SPTLC1 and RAB7 and not be recognised as familial. OBJECTIVE: To screen persons with dominantly inherited HSAN I and others with idiopathic sensory neuropathies for known mutations of SPTLC1 and RAB7. PATIENTS: DNA was examined from well characterised individuals of 25 kindreds with adult onset HSAN I for mutations of SPTLC1 and RAB7; 92 patients with idiopathic sensory neuropathy were also screened for known mutations of these genes. RESULTS: Of the 25 kindreds, only one had a mutation (SPTLC1 399T-->G). This kindred, and 10 without identified mutations, had prominent mutilating foot injuries with peroneal weakness. Of the remainder, 12 had foot insensitivity with injuries but no weakness, one had restless legs and burning feet, and one had dementia with hearing loss. No mutation of RAB7 was found in any of these. No known mutations of SPTLC1 or RAB7 were found in cases of idiopathic sensory neuropathy. CONCLUSIONS: Adult onset HSAN I is clinically and genetically heterogeneous and further work is required to identify additional genetic causes. Known SPTLC1or RAB7 mutations were not found in idiopathic sensory neuropathy.

Acyltransferases↗
PubMed2003

The gene for HMSN2C maps to 12q23-24: a region of neuromuscular disorders.

BACKGROUND: Hereditary motor and sensory neuropathy type 2C (HMSN2C, Charcot-Marie-Tooth 2C [CMT2C]) is an autosomal dominant motor and sensory neuropathy involving limb, diaphragm, vocal cord, and intercostal muscles. OBJECTIVE: To identify the chromosome localization for this disorder in one large American family of English and Scottish ethnicity. METHODS: Variable clinical severity led the authors to combine several approaches to accurately identify affected patients. Genome-wide two-point linkage analysis, high-definition mapping, and multipoint and recombinant haplotype analyses were performed. Mutation analysis of the triplet repeat region of ataxin-2 was also carried out. RESULTS: The initial genome-wide scan identified a region at 12q24, and fine mapping provided a maximal lod score of 4.73 (D12S1645 and D12S1583 at theta = 0.01 and 0, respectively). With multipoint analysis, a higher lod score of 5.17 was obtained and localized to the same region at 119.0 cM. Haplotype analysis narrowed the region to approximately 5.0 cM between D12S1646,D12S1330 and D12S105,D12S1339 (12q23.3-24.21). Ataxin-2, the gene responsible for spinocerebellar ataxia type 2 (SCA2), localizes to this region, but no triplet repeat expansion or point mutations within the repeat were found. CONCLUSIONS: The gene for HMSN2C maps to 12q23-24. This region is associated with SCA2, scapuloperoneal spinal muscular atrophy, and congenital distal spinal muscular atrophy. Further studies are needed to demonstrate the specific gene alteration and its relationship with nearby genes.

Age of Onset↗
PubMed2000

Hereditary motor and sensory neuropathy type 2C is genetically distinct from types 2B and 2D.

BACKGROUND: Linkage analysis studies have identified 3 genetically different varieties of hereditary motor and sensory neuropathy type 2 (HMSN 2, also called Charcot-Marie-Tooth disease type 2, or CMT 2): HMSN 2A (linked to 1p35-p36), 2B (to 3q13-q22), and 2D (to 7p14). Hereditary motor and sensory neuropathy type 2C is characterized by diaphragmatic and vocal cord paresis; its disease locus has not been mapped. OBJECTIVE: To determine whether the HMSN 2C phenotype, previously shown not to be linked to the HMSN 2A locus, is linked to the HMSN 2B or HMSN 2D loci. DESIGN: Linkage analysis. SETTING AND PATIENTS: Thirty-three subjects, including 12 affected individuals and 11 individuals at risk, in a large family with HMSN 2C. RESULTS: Evidence was found against linkage of HMSN 2C phenotype to either the HMSN 2B or the 2D loci. CONCLUSIONS: HMSN 2C is genetically distinct from HMSN 2A, 2B, and 2D. We think that at least 4 genetically distinct varieties of autosomal dominant HMSN 2 exist.

Alleles↗
PubMed2000

Percutaneous treatment of carpal, metacarpal, and phalangeal injuries.

Percutaneous fixation of hand fractures is a common technique that takes advantage of the subcutaneous nature of hand bones, their small size, and their limited loading potential for stress placed on hardware. Percutaneous wire fixation supplements cast fixation when plaster cannot hold particular reductions, and allow surgical fixation with limited postoperative swelling. In the first part of the current study, the types of wires that are used for hand fixation, fluoroscopy, helpful instruments, and the basic techniques used for this type of surgery are discussed. In the second part of the study, specific fixation techniques for different fractures of the carpals, metacarpals, and phalanges are outlined.

Bone Screws↗
PubMed1999

Immobilization of the mallet finger. Effects on the extensor tendon.

Since the mallet finger that is treated with isolated splinting of the distal interphalangeal (DIP) joint can be moved freely proximal to the DIP joint, we sought to determine whether such motion might cause a tendon gap that could explain the extensor lag that often follows treatment. Experiments were performed on 32 cadaveric fingers with open mallet finger lesions, immobilizing either the DIP joint alone or both the DIP and PIP joints, while repeatedly flexing and extending the more proximal finger and wrist joints. For each experiment, the gap in the extensor tendon was measured. Joint motion proximal to the DIP joint and retraction of the intrinsics did not cause a tendon gap in a finger with a mallet lesion, supporting the convention that only the DIP joint needs to be immobilized.

Bone Wires↗
PubMed1999

Histology of the extensor retinaculum of the wrist and the ankle.

The extensor retinaculum of the wrist has been used for reconstruction of the annular pulleys of the flexor sheath. We examined the histologic structure of the extensor retinaculum and tendon sheath of the wrist and ankle in cadaveric specimens using hematoxylin-eosin and Verhoeff-van Gieson stains to detect elastin and alcian blue to detect hyaluronic acid, comparing the structure with that described previously for the annular pulleys. Three distinct layers are identified in the retinaculums of both the ankle and wrist: the inner gliding layer, with hyaluronic acid-secreting cells, shows isolated chondroid metaplasia; the thick middle layer contains collagen bundles, fibroblasts, and interspersed elastin fibers; and the outer layer consists of loose connective tissue containing vascular channels. This basic 3-layered histologic composition of the extensor retinaculum is carried in anatomic pulleys throughout the body and appears to represent an adaptive mechanism to provide both a smooth gliding surface as well as the mechanical strength to prevent tendon bowstringing. Given the same histologic structure as the annular pulleys, the extensor retinaculum is a reasonable biologic replacement for the reconstruction of deficient annular pulleys. Likewise, the extensor retinaculum of the ankle could be used to reconstruct a deficient retinaculum of the wrist.

Ankle↗
PubMed1999

Comparative histology of the annular and cruciform pulleys.

Twenty annular and 12 cruciform pulleys were dissected from four unembalmed fresh cadaveric fingers and stained with haematoxylin and eosin, Verhoeff-van Gieson stain for elastin, alcian blue stain for hyaluronic acid, and a separate stain for S-100 to identify chondroid cells. Three distinct layers were identified in both annular and cruciform pulleys: an outer layer of fibrofatty tissue with vascular channels outermost, an inner layer of hyaluronic acid-secreting cells, and a collagen-rich layer in between. Chondroid metaplasia was noted in the inner layer of both types of pulleys. Minimal differences were noted in regard to the elastin fibre content of the pulleys, with slightly more elastin in the annular pulleys, but no other differences were noted.

Aged↗
PubMed1998

Anatomy and histology of the A5 pulley.

Since the anatomy and actual existence of the A5 pulley have been variably reported in the literature, we sought to better define its macroscopic and microscopic structure. Thirty-one A5 pulleys were dissected from 32 fingers. The average proximal to distal length was 3.8 mm; the average width was 8.9 mm. The distal edge of the pulley was proximal to the distal interphalangeal joint, 7.7 mm from the profundus tendon insertion. On histologic study by light microscopy, 3 distinct layers were noted; fibrofatty tissue was noted in the outermost layer, hyaluronic acid-secreting cells were noted in the innermost layer, and connective tissue containing collagen bundles, fibrocytes, and interspersed elastin fibers was noted in the middle layer. The A5 pulley is a discrete structure, with measurements as noted as well as a histologic composition consistent with that reported for the other annular pulleys.

Fingers↗
PubMed1998

Operative treatment of hip fractures in patients with renal failure.

The conditions of a hip fracture and renal failure cause particularly high mortality. Eight patients (average age, 63 years) who had operative treatment for nine hip fractures were studied retrospectively. Three had intertrochanteric fractures fixed with sliding compression screws, and five had femoral neck fractures (bilateral in one patient): two nondisplaced femoral neck fractures were fixed with percutaneous screws, and four displaced femoral neck fractures were treated with arthroplasties in three and percutaneous screws in one. Operative treatment was done when the patient was in medically stable condition (average, 8 days). Full weightbearing was allowed on the injured limb after surgery. Early morbidity analysis showed no wound infections, thromboembolic events, or hemorrhagic complications. The first year mortality was three (38%). Late morbidity included one nonunion and one sliding screw penetration. Total mortality at 6 years was seven (88%) patients, with an average postoperative survival time of 28 months. Preoperative ambulation was preserved in five of seven (71%) patients. One the basis of this study, it appears that a team approach to operative management including nephrologist and surgeon helps to reduce short term complications and mortality and allows such patients to be mobilized and regain ambulation.

Aged↗
PubMed1997

Sensitivity of objective parameters in the diagnosis of pediatric septic hips.

This study examines the sensitivity of temperature, leukocyte count, and erythrocyte sedimentation rate in the diagnosis of pediatric septic arthritis of the hip by retrospective case analysis of 26 children, aged 0 to 6 years, in hospitals of central Brooklyn. The average presenting temperature was 38.4 degrees C, with 65% of the patients having had a temperature higher than 38 degrees C. The average leukocyte count was 13,500 per mL, with 73% of patients having a leukocyte count greater than 9000 per ml. The average erythrocyte sedimentation rate (21 cases) was 51 mm per hour, with 95% of the patients presenting with an erythrocyte sedimentation rate greater than 20 mm per hour. Of these children with septic hips, only 5% had a normal erythrocyte sedimentation rate, although 35% had a normal temperature and 27% had a normal leukocyte count. Neonates (age younger than 1 month) were not febrile (average temperature, 36.7 degrees C) and did not have an elevated leukocyte count (average leukocyte count, 9300 per mL) but did have an elevated erythrocyte sedimentation rate (average erythrocyte sedimentation rate, 45 mm per hour). Of these 3 values, erythrocyte sedimentation rate is the most sensitive indicator of septic arthritis of the hip in children 0 to 6 years of age.

Arthritis, Infectious↗
PubMed1996

Pharmacokinetics in postanesthesia recovery: implications for nurses.

As the number of drugs used in the treatment of patients increases, nurses must be more knowledgeable about their activity and actions. This article reviews principles of pharmacokinetics, which is the study of how drugs attain their concentrations in the blood stream. The phases of absorption, distribution, biotransformation, and excretion are presented, and examples of common drugs are related to these phases.

Biological Availability↗
PubMed1996

Local-advancement soft-tissue coverage in a child with ipsilateral grade IIIB open tibial and ankle fractures.

This case describes the successful treatment of a child with a vascular injury and two ipsilateral grade IIIB open lower leg fractures using two local-advancement soft-tissue techniques. Multiple relaxing skin incisions were used for closure of the wound associated with the patient's midshaft tibial fracture, whereas a randomly patterned rotational fasciocutaneous flap was used for coverage of the wound associated with the patient's medial malleolar fracture. These straightforward local-advancement soft-tissue coverage techniques allowed for treatment of a child with vascular injuries, ensuring the viability of the foot, while preventing distant donor site morbidity and functional sacrifice. Additionally, no special microsurgical or specialty training is necessary to achieve a similar result.

Ankle Injuries↗