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Biomedical subjects

W H Lo

Publications and source records attributed to W H Lo.

At least 91 records · Page 5Linked to original sources
PubMed1993

Changes in gait and maximum ankle torque in patients with ankle arthritis.

Findings from quantitative gait analysis and maximum ankle torque were used to assess the walking pattern of patients with ankle arthritis and to correlate the changes of gait parameters and muscle strength with severity of arthritis. Gait analysis and the isokinetic maximum ankle torque test were performed in 20 patients with first to fourth degree traumatic ankle arthritis. Six patients without evidence of traumatic arthritis were used as controls. Isokinetic maximum ankle plantarflexion and dorsiflexion torques were determined with Cybex instrumentation. Force plate and foot switch data were gathered during level walking. Maximum ankle plantarflexion and dorsiflexion torques were diminished in the injured ankles. Velocity, stride length, and cadence were decreased in arthritic patients compared with controls. The arthritic limbs had shorter single limb stance and longer double stance during free and fast walking speeds compared with the controls' affected ankles. The patterns of ground reaction forces were similar in the injured and uninvolved limbs as well as the control subjects, except the magnitude of vertical forces during push-off were reduced in arthritic ankles. The gait parameters and muscle strength deteriorated as the arthritis became severe, but they showed significant changes only when the patients had third or fourth degree arthritis.

Adult↗
PubMed1993

Epiphyseal fracture-retrosternal dislocation of the medial end of the clavicle: a case report.

Epiphyseal fracture-retrosternal dislocation of the medeial end of the clavicle is an unusual injury. It may occur as a result of a blow either indirectly on the posterolateral aspect of the shoulder girdle or directly over the sternal end of the clavicle. It is clinically impossible to differentiate from the true posterior dislocation even with the computed tomography, but the treatment for either lesion is the same. Recently we uneventually treated a 15-year-old boy with conservative treatment and got a satisfactory result. The purpose of this paper is to draw the attention of the readers to the rarity and serious nature of such injury and the potential difficulties in establishing diagnosis and achieving reduction.

Adolescent↗
PubMed1993

Multiple glomus tumors: a case report.

Multiple glomus tumor (MGT) is rare in incidence. A 37-year-old male was diagnosed to have localized MGT over his right leg. With the characteristics of unusual location (right lower leg), development in sequence, and distribution along the course of the lateral sural cutaneous nerve. Its pathological findings were also characteristic. When the overall presentations showed in cases with recurrent symptoms and signs of glomus tumor after surgical excision, recurrence and multiplicity should be considered.

Adult↗
PubMed1992

Skeletal metastasis from occult carcinoma.

We reviewed 177 patients with skeletal metastases, seen between 1984 and 1989, to define the characteristics of metastatic bone disease from an occult primary carcinoma. In 52 (30%) patients, the primary carcinomas could not be identified when the bone metastases were first diagnosed. This group was predominantly male, with intractable pain the most common symptom. The primary tumors were identified on antemortem evaluation in 28 (54%) patients after extensive examination. Among these, the primary tumor was in the lung in 9 patients, followed by liver (8), kidney (5), prostate (3), thyroid gland (2), and rectum (1). The identifiable occult malignancies possessed three common features: all were osteophilic tumors, all had a high incidence in the specific geographic area, and all were not amenable to early detection. The mean survival of these patients was 11 months. Current treatment modalities failed to affect the course of these patients, except for those with primary carcinomas of the kidney and prostate. This observation attests to our limitations in both the diagnosis and treatment of this problem. Efforts should be directed primarily toward excluding those common and/or treatable tumors only.

Bone Neoplasms↗
PubMed1992

Identification of three novel missense PKU mutations among Chinese.

Three novel missense mutations have been identified in the phenylalanine hydroxylase (PAH) genes of Chinese individuals afflicted with various degrees of phenylketonuria (PKU). A T-to-C transition was observed in exon 5 of the gene, resulting in the substitution of Phe161 by Ser161. Two substitutions, G-to-T and T-to-G, were observed in exon 7, resulting in the substitution of Gly247 by Val247 and Leu255 by Val255, respectively. Expression analysis demonstrated that these mutant proteins produced between 0 and 15% of normal PAH enzyme activity. Population screening of a Chinese sample population indicates that these mutations are quite rare, together accounting for only about 4% of all PKU alleles among the Chinese. The P161S and G247V mutations were each present on a single PAH RFLP haplotype 4 chromosome in patients form Northern China, while the L255V mutation was present on chromosomes of both haplotypes 18 and 21 in patients from Southern China. These results suggest that the remaining 30% of uncharacterized PKU alleles in the Chinese population may bear a large number of relatively rare PAH mutations.

Alleles↗
PubMed1992

Identification of three novel PKU mutations among Chinese: evidence for recombination or recurrent mutation at the PAH locus.

Three novel mutations have been identified in the phenylalanine hydroxylase (PAH) genes of Chinese classical phenylketonuria (PKU) patients. Two of these substitutions (W326X and Y356X) result in the generation of a premature stop codon, while the third (IVS-7nt2) alters an invariant dinucleotide splicing signal. These mutations together account for about 10% of all PKU alleles in the Chinese population. The W326X mutation is associated with PAH RFLP haplotype 4, the most common haplotype in Orientals, while the IVS-7nt2 mutation occurs once on a haplotype 7 chromosome. The Y356X mutation is associated with multiple haplotypes, possibly due to crossover, gene conversion, or recurrent mutation.

Asian People↗
PubMed1992

Avascular necrosis of the femoral head--an unusual complication of an intertrochanteric fracture.

Avascular necrosis of the femoral head is an uncommon complication after intertrochanteric fracture. We report six patients with this unusual complication 1-5 years after intertrochanteric fracture. The possible etiologies of this complication include a more proximal intertrochanteric fracture, a high-energy injury with fracture displacement resulting in vascular damage, and adverse influences of the operative procedures on the vascularity of the femoral head.

Adult↗
PubMed1992

Rotator interval tear: a case report.

Rotator cuff tear is one of the most common shoulder disorders. Most of the tears involve the critical area of the supraspinatus tendon. The rotator interval tear is extremely rare. Tear in this area is important due to its relationship with shoulder instability, different clinical symptom and different management. Recently we have uneventually treated a case with rotator interval tear after a violent throwing injury. The purpose of the paper is to emphasize the clinical differences of this unusual tear.

Humans↗
PubMed1991

Founder effect of a prevalent phenylketonuria mutation in the Oriental population.

A missense mutation has been identified in the human phenylalanine hydroxylase [PAH; phenylalanine 4-monooxygenase; L-phenylalanine, tetrahydrobiopterin:oxygen oxidoreductase (4-hydroxylating), EC 1.14.16.1] gene in a Chinese patient with classic phenylketonuria (PKU). A G-to-C transition at the second base of codon 413 in exon 12 of the gene results in the substitution of Pro413 for Arg413 in the mutant protein. This mutation (R413P) results in negligible enzymatic activity when expressed in heterologous mammalian cells and is compatible with a classic PKU phenotype in the patient. Population genetic studies reveal that this mutation is tightly linked to restriction fragment length polymorphism haplotype 4, which is the predominant haplotype of the PAH locus in the Oriental population. It accounts for 13.8% of northern Chinese and 27% of Japanese PKU alleles, but it is rare in southern Chinese (2.2%) and is absent in the Caucasian population. The data demonstrate unambiguously that the mutation occurred after racial divergence of Orientals and Caucasians and suggest that the allele has spread throughout the Orient by a founder effect. Previous protein polymorphism studies in eastern Asia have led to the hypothesis that "northern Mongoloids" represented a founding population in Asia. Our results are compatible with this hypothesis in that the PKU mutation might have occurred in northern Mongoloids and subsequently spread to the Chinese and Japanese populations.

Asian People↗
PubMed1991

Missense mutations prevalent in Orientals with phenylketonuria: molecular characterization and clinical implications.

Two missense mutations in the phenylalanine hydroxylase (PAH) genes of Orientals with phenylketonuria (PKU) have been identified. A G-to-A transition in exon 7 of the gene results in the substitution of Gln243 for Arg243 (R243Q) and accounts for 18% of all PKU chromosomes among Chinese. An A-to-G transition in exon 6 of the gene results in the substitution of Cys204 for Tyr204 (Y204C) and identifies about 13 and 5% of all PKU chromosomes in the Chinese and Japanese populations, respectively. The R243Q construct produced less than 10% of normal PAH activity in in vitro expression analysis in a eukaryotic cell system, and patients homozygous for this substitution exhibit a severe clinical phenotype. These results are consistent with previous findings in this expression system. The Y204C construct, however, produced near normal levels of PAH enzyme activity and immunoreactivity in this in vitro expression system. Because this substitution is present only on PKU chromosomes, it is a valuable marker for identifying the corresponding mutant allele for carrier screening of PKU. With the characterization of these two substitutions, about 60% of PKU alleles in China can now be identified. The continuing search for additional PKU mutations will permit effective carrier screening and prenatal gene diagnosis of PKU in East Asia.

Alleles↗
PubMed1991

Identification of a novel phenylketonuria (PKU) mutation in the Chinese: further evidence for multiple origins of PKU in Asia.

A novel mutation has been identified in the human phenylalanine hydroxylase (PAH) gene of a Chinese patient with classical phenylketonuria (PKU). It is a single base transition of G to A at the last base in intron 4 of the gene, which abolishes the 3'-acceptor site of the intron. Population screening indicates that this mutation constitutes about 8% of all PKU chromosomes in Chinese but is absent in Japanese and Caucasian PKU patients. It is prevalent in southern China but rare in northern China, providing additional evidence that there were multiple founding populations of PKU in east Asia.

Alleles↗
PubMed1990

Risk factors of suicide among schizophrenics.

This case control study included 74 Chinese schizophrenics (DSM-III criteria) who died of suicide and 74 age- and sex-matched nonsuicide schizophrenics. Sociodemographic variables were unrelated with suicide. Associations were found between suicide and severity of illness (more frequent admissions, higher dose of medication and earlier appointments), history of major depressive episodes and suicidal attempts, last admission for reasons other than schizophrenic symptoms alone, and suicidal ideas on mental state examination. The last 2 factors, together with the maintenance dose of medication, were identified as the most important risk factors by logistic regression analysis.

Adult↗
PubMed1990

Osteoid osteoma: clinical and investigative features.

From 1979 to 1988, 15 cases of osteoid osteoma were diagnosed and treated at our hospital. There were 10 males and 5 females, the average age at the time of diagnosis was 17.2 years (from 5 to 54 years). The clinical features were night pain and localized pain in most cases. There was distinct pain relief by salicylate in 58% of the patients with a therapeutic trial. The duration of symptoms before diagnosis averaged 17.9 months (from 1 month to 10 years). Most of the lesions were located in the lower extremities, predominantly in the femur. The hip was a commonly affected site in children and young adults. The X-ray findings in the affected area were classical of the lesion in only 47% of the cases, therefore, preoperative localization of the nidus was aided by either tomography or CT scan. Intraoperative localization by use of an image intensifier and by taking X-rays of the excised specimen has proven to be reliable. All cases underwent en bloc resection of the lesion, and all of the patients were symptom free immediately after the operation, except for one recurrence. A second operation was performed in this case 2 years later and was successful, with pathological confirmation. Fourteen tumors were confirmed by histopathological study, one case could not be confirmed by pathological examination, however the patient obtained complete relief of symptoms postoperatively.

Adolescent↗
PubMed1990

Legg-Calve-Perthes disease: clinical analysis of 57 cases.

The rarity of the Legg-Calve-Perthes disease (LCPD) in Chinese children in Hong Kong has been reported. However, this hip disorder is not uncommon among children in Taiwan between the ages of 3 and 9. Fifty-seven patients with LCPD were observed during a 4-year period. Of these, 47 hips in 43 patients were followed up through a significant course of the disease, with an average period of 38.8 months. The mean age at onset of symptoms was 6.6 years for boys and 7.1 years for girls. Over half of the patients (67%) were older than 6 years of age at onset of the disease. The male: female ratio was 5:1, and the incidence of bilateral involvement was 10%. The majority (85%) belonged to Catterall's group 3 or 4. The skeletal maturity of 17 (68%) these children was delayed an average of 31.8 months. Fifty-three percent of the patients were from families of low socioeconomic status. Delay in diagnosis and presentation with painless limp and stiffness were common. Orthotic management was employed in 15 hips. Surgical containment, either by varus-rotation femoral osteotomy or innominate osteotomy, was achieved in 16 hips. The remaining 16 hips received no treatment. The overall results showed an increase in improvement from 19% to 47% after active treatment of the disease. The chance of satisfactory treatment was reduced considerably when the disease started after the age of 6 years, this was especially obvious in untreated hips. No significant differenced in the healing time between the nonsurgical group and the surgical group was observed.

Age Factors↗
PubMed1989

Suicide among Chinese schizophrenics in Hong Kong.

A descriptive study of suicides in 74 Chinese schizophrenic out-patients (43 male) is presented. The mean age at death was 31.3 years. The mean duration of illness was 8.5 years and 50 of the 74 died within ten years of onset of illness. Only five lived alone; 35 were openly employed and 20 were married at the time of death. Twenty had a history of depression, and 27 had attempted suicide previously. More females had been depressed or had attempted suicide than males. Over half were last admitted for reasons other than schizophrenic symptoms alone and ten died within one month of discharge. Eight of 71 patients followed up expressed suicidal ideas at the last psychiatric contact, but only 15 were symptomatic. Jumping was the commonest method used. Analytical studies are needed to identify risk factors in Chinese schizophrenics.

Adult↗
PubMed1989

Polymorphic DNA haplotypes at the phenylalanine hydroxylase (PAH) locus in Asian families with phenylketonuria (PKU).

DNA polymorphisms at the phenylalanine hydroxylase (PAH) locus have proved highly effective in linkage diagnosis of phenylketonuria (PKU) in Caucasian families. More than 10 RFLP sites have been reported within the PAH structural locus in Caucasians. With information from affected and unaffected offspring in PKU families it is often possible to reconstruct complete RFLP haplotypes in parents and to use these haplotypes to follow the segregation of PKU within families and to determine the distribution of PKU chromosomes within populations. To establish the utility of these RFLPs in characterizing Asian families with PKU, we typed eight DNA sites in 21 Chinese families and 12 Japanese families with classical PKU. The eight RFLPs were chosen for their informativeness in Caucasians. From these families we reconstructed a total of 91 complete PAH haplotypes, 44 from non-PKU chromosomes and 47 from PKU-bearing chromosomes. Although all eight marker sites are polymorphic in both Chinese and Japanese, there is much less haplotypic variation in Asians than in Caucasians. In particular, one haplotype alone, haplotype 4, accounts for more than 77% of non-PKU chromosomes and for more than 80% of PKU-bearing chromosomes. Haplotype 4 is also relatively common in Caucasians. The next most common Asian haplotype is 10 times less frequent than haplotype 4. By contrast, in many Caucasian populations the sum of the frequencies of the five most common haplotypes is still less than 80%, and several of the most common haplotypes are equally frequent. Even though the extent of haplotypic variation in Asians is severely limited, the few haplotypes that are found often differ at a number of RFLP sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1989

Molecular genetics of phenylketonuria in Orientals: linkage disequilibrium between a termination mutation and haplotype 4 of the phenylalanine hydroxylase gene.

Phenylketonuria (PKU) is a common metabolic disorder among Chinese, with a prevalence of about 1 in 16,500 births. This frequency is very similar to that among Caucasians. Individual exons of the phenylalanine hydroxylase (PAH) gene with flanking introns were amplified by polymerase chain reaction and cloned into M13 for sequence analysis. An Arg111-to-Ter111 mutation has been identified in exon 3 of the PAH gene in a Chinese PKU patient. The mutation is in linkage disequilibrium with the mutant haplotype 4 alleles which are the most prevalent haplotype among the Orientals. The mutation accounts for about 10% of the Chinese PKU alleles and is absent from the Caucasians, demonstrating that independent mutational events have occurred in the PAH locus after racial divergence.

Asian People↗