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Biomedical subjects

C L Cheng

Publications and source records attributed to C L Cheng.

At least 73 records · Page 4Linked to original sources
PubMed1990

Vitamin D status among patients with fractured neck of femur in Hong Kong.

Vitamin D deficiency leads to secondary hyperparathyroidism initially and then to mild osteomalacia, both of which conditions may be aymptomatic and may predispose to bone fracture. To assess the importance of vitamin D deficiency in predisposing to fractured neck of femur, we studied the vitamin D status, dietary intake and socio-economic characteristics in 69 patients with fractured neck of femur (group A), 28 normal subjects with age above 60 (group B), and 101 normal volunteers (group C). Patients with fractured neck of femor had significantly lower levels of serum 25-hydroxy-cholecalciferol compared with subjects of groups B and C. There is no statistically significant difference in other biochemical parameters, including calcium, phosphate, and alkaline phosphatase. Patients with fractured neck of femur and with 25-hydroxycholecalciferol below 20 ng/mL were characterized by a home-bound and/or institutionalized life-style, smaller living place, and limited access to open space. To conclude, hypovitaminosis D is a common problem among elderly patients with fractured neck of femur in Hong Kong. The fact that such vitamin D deficiency is associated with muscle weakness may contribute to falls, and thus indirectly account for an increased rate of hip fractures over the normal control.

Aged↗
PubMed1990

25-Hydroxycholecalciferol and insulin-like growth factor I are determinants of serum concentration of osteocalcin in elderly subjects with and without spinal fractures.

Osteocalcin is one of the major proteins in the osseous matrix. To evaluate the determinants and thus the physiological control of osteocalcin production in normal and osteoporotic subjects, the serum levels of osteocalcin, 25-hydroxycholecalciferol (25-OH-D3), and insulin-like growth factor I (IGFI) were measured by radioimmunoassay in 44 subjects over 60 years old. Circulating osteocalcin, 25-OH-D3, and IGFI were 0.28 +/- 0.10 nmol/L (1.65 +/- 0.96 ng/mL), 70.5 +/- 25.1 nmol/L (28.3 +/- 10.1 ng/mL), and 23.8 +/- 12.0 nmol/L in 27 healthy controls respectively, as compared with 0.09 +/- 0.09 nmol/L (0.52 +/- 0.52 ng/mL), 48.2 +/- 19.9 nmol/L (19.35 +/- 7.91 ng/mL), and 16.56 +/- 6.96 nmol/L in 17 patients with spinal fractures. Significant correlation was found between osteocalcin and 25-OH-D3 level, as well as between osteocalcin and IGFI. The results show that IGFI and 25-OH-D3 are important determinants for serum concentration of osteocalcin in elderly subjects with and without spinal fractures.

Aged↗
PubMed1990

Isolation of transcriptionally regulated root-specific genes from tobacco.

Four root-specific cDNA clones and their corresponding genomic clones have been isolated from tobacco (Nicotiana tabacum) by a novel differential hybridization procedure. The genes are expressed at high levels in roots and are not detectable in leaves. The cDNAs are encoded by small gene families of two to four members. Transcription experiments with isolated nuclei demonstrate that the genes are, at least in part, transcriptionally regulated. Constructions in which 1.4 kilobase pairs of 5' flanking region of one of the root-specific genes was fused to a reporter gene (beta-glucuronidase) were transformed into tobacco. beta-Glucuronidase activity in transgenic plants was localized in the roots, demonstrating the cis-acting sequences regulating root-specific expression are present on the 5' flanking region.

Journal Article↗
PubMed1990

Small cell carcinoma of the urinary tract.

Small cell carcinomas of the urinary tract are rare, but lethal. We report 3 cases of primary small cell carcinoma of the kidney, urinary bladder and prostate with light microscopic, immunohistochemical and electron microscopic findings. One patient with small cell carcinoma of the prostate died of disseminated disease 2 years after diagnosis and another patient with small cell carcinoma of the urinary bladder was free of tumour after 6 months. A partial remission was induced in the third patient with distant metastases of small cell carcinoma of the kidney by using chemotherapy protocols similar to the drug regimens for small cell carcinomas of the lung; the patient survived for 5 months. Immunohistochemical studies revealed the absence of argyrophilic immunostaining of tumour cells in all 3 cases, positive staining for keratin in 2 and staining for neuron-specific enolase in all 3. In the third patient, reactivity for prostate-specific antigen was negative. Dense-core, membrane-bound granules were identified in the cytoplasm of 2 patients. The paraneoplastic syndrome was not found, indicating that in considering the occurrence of ectopic hormones, specific cytoplasmic granules of origin need not be implicated. Recognition of this distinct entity requires full consideration of morphological, immunohistological, ultrastructural and biological features. In order to define the origin of this tumour more clearly and to evaluate the effectiveness of chemotherapy, larger series of patients are needed.

Adult↗
PubMed1990

Tuberculosis of the lumbosacral junction. Long-term follow-up of 26 cases.

Of 37 consecutive patients suffering from tuberculosis of the lumbosacral spine, 26 were reviewed after an average follow-up of 20 years. Those presenting at under 10 years of age usually had a discharging sinus or a pointing abscess and a visible kyphosis. In older patients, low back pain was the predominant presenting symptom. Neurological involvement was uncommon. Both operative and conservative treatment had resulted in fusion but all patients treated conservatively ended up with a kyphosis associated with trunk shortening. They had a higher incidence of back pain and more complications in pregnancy. Anterior debridement and fusion with a strut graft can reduce the incidence and size of kyphosis, but is technically demanding. Treatment remains difficult and requires individual consideration.

Adolescent↗
PubMed1989

Long-term results and complications of cement augmentation in the treatment of unstable trochanteric fractures.

Thirty-eight patients with unstable trochanteric fractures of the femur were treated with Dimon-Hughston displacement osteotomy and cement augmentation at the fracture site. Of these patients 76 per cent had excellent and good results after an average follow-up of 3.7 years (range 2-5 years). Late complications occurred in six hips. These included non-union at the trochanteric fracture, protruding pin, partial destruction of the femoral head, subcapital fracture of the femoral neck, and avascular necrosis of the femoral head. All complications occurred late (1 year after surgery) and were related to inappropriate placement and excessive amount of cement, together with inadequate new bone formation. The augmentation of cement provided early stability for early mobilization in these elderly patients. However, when improperly used, late complications can occur.

Aged↗
PubMed1989

Post-traumatic oedema of the foot after tibial fracture.

A total of 97 patients with diaphyseal tibial fractures treated with functional bracing were studied prospectively. Persistent ipsilateral foot swelling was present in 84.5 per cent of the patients. Most of the swellings subsided with time, but a small percentage of them persisted for a duration of 2 years or more after injury. The time for disappearance of the swelling in 50 per cent of the patients was 18.6 weeks. The development of oedema is not related to the age and sex of the patients, the configuration, type and level of the fractures, or the association of a fibular fracture. The bone healed quicker in those who did not have swelling of the foot. Once the swelling has developed, it seems to run its own course and its disappearance is not related to the age and sex, the configuration, type and level of fractures, the association of a fibular fracture, or the time for fracture healing. This complication does not have any adverse effect on the functional recovery of the patients.

Adolescent↗
PubMed1989

Prognostic factors and progress for ambulation in elderly patients after hip fracture.

A longitudinal study of the ambulation progress was done on 102 patients in the first 9 wk after an operation for repair of hip fractures. The time taken to achieve a stable walking pattern from frame to a cane was recorded for every patient. Results showed that 82.2% of the patients were able to walk with a cane at 4 wk postoperatively. Of the remaining 17.8% of the patients, 7.7% were able to walk with a cane at 6 wk whereas 10.1% were not able to walk with a cane at 6 wk. Several factors including the age, sex, mental state, the type of operation and the preoperative ambulation level of the patients were studied to predict the ambulation progress of the patients. The most important factors affecting the ambulation progress were the age and the preoperative ambulation level of the patient. Because of the general trend in the aging of the population, an increase in the number of hip fractures is expected. The result of this study may help in predicting the prognosis and provide guidance for restoring the function of the patients.

Aged↗
PubMed1989

Anterior spinal fusion for spondylolysis and isthmic spondylolisthesis. Long term results in adults.

We reviewed 20 adult patients with spondylolysis and isthmic spondylolisthesis an average of 10.5 years after treatment by anterior spinal fusion. Nineteen patients had excellent or satisfactory results. Ten of the patients were symptom-free at one year, and 15 were asymptomatic at final follow-up. Anterior spinal fusion can produce results comparable to those of posterior fusion with or without decompression. The results tend to improve with time in contrast to the known worsening of late results after posterior decompression without fusion.

Adolescent↗
PubMed1988

A new locus (NIA 1) in Arabidopsis thaliana encoding nitrate reductase.

We have isolated two nitrate reductase genes and their corresponding cDNAs from Arabidopsis thaliana. Sequences of the two cDNAs, when compared to a sequence of a barley cDNA clone, confirm their identity as nitrate reductase clones and show that they are closely related. The two genes have been mapped using restriction fragment length polymorphisms; gNR2 is close to the previously identified chl-3 locus and is probably identical to it, while gNR1 maps to a new locus (NIA1) on chromosome 1, near gl-2.

Amino Acid Sequence↗
PubMed1988

The effect of traumatic brain injury on the visual system: a morphologic characterization of reactive axonal change.

Reactive axonal changes following fluid-percussion brain injury were studied in the highly organized afferent pathways of the cat visual system. The visual system offers several features advantageous to the study of traumatic brain injury. Specifically, as the retinal cells of origin of the optic nerve and tract are isolated from the employed fluid-percussion injury, concomitant traumatically induced somatic change is not a confounding variable. Additionally, the existence of axons of varying diameters and topographic localization within the visual pathways allows the relationship between both fiber size and distribution and their predilection for traumatically induced change to be considered. Since the visual pathway is a highly organized sensory pathway, data obtained in this system can be compared with similar studies previously conducted in motor systems. In these experiments, 20 adult cats were subjected to brain injury and killed at posttraumatic survival periods ranging from 2 to 60 days. Six cats received intravitreous injections of horseradish peroxidase (HRP) to aid in the recognition of axonal change. At the designated survival time, all animals were perfused with aldehydes. The visual system from optic chiasm to lateral geniculate was sectioned and prepared for routine light (LM) and electron microscopic (TEM) study. Animals injected with HRP were processed for the LM and TEM visualization of HRP reaction products. By the second posttraumatic day, reactive axonal swellings were observed in the optic tracts as they entered the medial intralaminar nuclei of the lateral geniculate bodies. Proximal segments of the reactive axons showed enlargement and lobulation, whereas the distal segments underwent wallerian degeneration. Over a 2 week posttraumatic course, some axonal swelling persisted unchanged, some degenerated, and others initiated regenerative sprouting. with continued survival, however, all the reactive swellings manifested only progressive degenerative change. These reactive axonal changes appeared to constitute a primary response to the traumatic episode and occurred without concomitant damage to either the related brain parenchyma or its intrinsic vasculature. Although these findings replicate many of those previously described in motor pathways, new conceptual information has been provided. These studies preclude concomitant somal damage as a confounding variable and suggest that large-caliber axons are susceptible to the shear and tensile forces of traumatic brain injury.

Animals↗
PubMed1988

Loosening of the porous coating in total knee replacement.

We reviewed 40 cementless Porous Coated Anatomic knee replacements in 34 consecutive patients. The average follow-up was 12.9 months (range 6 to 36 months). At review, loose beads were identified in 23 knees, in 11 on the femoral side and in 16 on the tibial side (in five knees on both sides). One loose bead was adjacent to the patella. In four knees there were intra-articular beads. Radiolucent lines at the interface between bone and prosthesis were seen in 19 knees, in six on the femoral side and in 16 on the tibial side (in three knees on both sides). In relation to the tibial component loose beads were associated with a radiolucent line in all except one case. Progressive loosening with an increasing number of loose beads was seen in three knees. At this early stage of follow-up there was no correlation between the clinical results and the presence of loose beads.

Adult↗
PubMed1988

Pott's paraplegia of late onset. The cause of compression and results after anterior decompression.

Twenty-two patients with late onset Pott's paraplegia presenting at a mean of 18 years after initial symptoms were reviewed an average of seven years after treatment by anterior decompression and fusion. Fourteen patients had active disease, and in 12 of these, activity at the internal kyphus was the direct cause of the paraplegia. In the other two, a soft healing bony ridge was the cause. The eight patients with healed disease had hard bony ridges compressing the cord. The response to anterior decompression was faster, better and safer in patients with active disease: nine recovered completely and three significantly. In patients with healed disease, the anterior decompression was technically more difficult and the recovery less satisfactory. Significant complications included two cases with neurological deterioration, two with cerebrospinal fluid fistulae and four with neurapraxia of the cord.

Adolescent↗
PubMed1986

Cloning and nitrate induction of nitrate reductase mRNA.

Nitrate is the major source of nitrogen taken from the soil by higher plants but requires reduction to ammonia prior to incorporation into amino acids. The first enzyme in the reducing pathway is a nitrate-inducible enzyme, nitrate reductase (EC 1.6.6.1). A specific polyclonal antiserum raised against purified barley nitrate reductase has been used to immunoprecipitate in vivo labeled protein and in vitro translation products, demonstrating that nitrate induction increases nitrate reductase protein and translatable mRNA. A partial cDNA clone for barley nitrate reductase has been isolated and identified by hybrid-selected translation. RNA blot-hybridization analysis shows that nitrate induction also causes a marked increase in the steady-state level of nitrate reductase mRNA.

Journal Article↗
PubMed1985

Somatosensory evoked potentials: monitoring cerebral functions following liver transplantation.

Serial somatosensory evoked potentials (SEPs) were obtained from a patient with Wilson's disease who had had liver transplantation. Correlating with recovery of hepatic encephalopathy and liver functions following the surgery, SEPs showed progressive normalization of peak latencies and waveforms. The data indicate that SEP may be a useful objective method in assessing recovery of cerebral functions following liver transplantation.

Adolescent↗