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Biomedical subjects

D J Harris

Publications and source records attributed to D J Harris.

At least 55 records · Page 3Linked to original sources
PubMed1993

The effects of dystrophin gene mutations on the ERG in mice and humans.

PURPOSE: The authors' earlier findings of a negative electroretinogram (ERG) in a boy with Duchenne muscular dystrophy (DMD) led them to investigate dystrophin gene deletions and ERGs in five boys with DMD. The authors wanted to determined whether there were similar ERG findings in an animal model for DMD, the mdx mouse. METHODS: Ganzfeld ERGs were recorded in five boys with DMD after a complete ophthalmic examination. The dystrophin gene was analyzed by Southern blot hybridization. ERGs were recorded in anesthetized mdx and control mice with a modified Grass photostimulator (Grass Instrument Company, Quincy, MA). RESULTS: Ophthalmic examinations in all five boys had normal findings, yet an abnormal negative ERG was recorded for each subject. The subjects' gene deletions were variable, ranging from large deletions to no detectable deletions. The ERGs of the mdx mice were normal and did not differ significantly from those of the control mice. CONCLUSIONS: The authors believe the unique ERG recorded for the human subjects is a manifestation of DMD associated with defects at the dystrophin gene locus and represents a new clinical entity. The ERG of the mdx mouse may be spared for several reasons, including milder effects of the mouse gene defect, differences in muscle and retinal gene product, or species differences in the biochemical role of dystrophin. The ERG shows promise of becoming a noninvasive diagnostic tool for DMD and its milder allelic forms.

Animals↗
PubMed1992

Efficacy of traditional Chinese herbal therapy in adult atopic dermatitis.

There has been considerable interest in traditional Chinese herbal therapy (TCHT) as a new treatment for atopic dermatitis. To establish the efficacy and safety of this treatment, a daily decoction of a formula containing ten herbs that has been found to be beneficial in open studies was tested in a double-blind placebo-controlled study. 40 adult patients with longstanding, refractory, widespread, atopic dermatitis were randomised into two groups to receive 2 months' treatment of either the active formulation of herbs (TCHT) or placebo herbs, followed by a crossover to the other treatment after a 4-week washout period. The main outcome measures were extent and severity of erythema and surface damage as judged by standardised body scores. The patients' own assessments of the overall response to treatment were also sought. The geometric mean score for erythema at the end of active treatment was 12.6 (95% confidence interval [CI] 5.9 to 22.0) and at the end of the placebo phase was 113 (65 to 180). The geometric mean score for surface damage was 11.3 (5.8 to 21.8) and 111.0 (68 to 182), respectively. The 95% CI for the mean geometric ratio for the two values with active treatment was 0.04 to 0.22 for erythema (p less than 0.0005) and 0.04 to 0.27 for surface damage (p less than 0.0005). Of the 31 patients who completed the study and expressed a preference, 20 preferred that phase of the trial in which they received TCHT whereas 4 patients preferred placebo (p less than 0.02). There was a subjective improvement in itching (p less than 0.001) and sleep (p less than 0.078) during the TCHT treatment phase. No side-effects were reported by the patients although many commented on the unpalatability of the decoction. TCHT seems to benefit patients with atopic dermatitis. Palatability of the treatment needs to be improved and its safety assured.

Administration, Oral↗
PubMed1992

Metabolic and histologic investigation of the nature of nephrocalcinosis in children with hypophosphatemic rickets and in the Hyp mouse.

To investigate the biochemical nature of nephrocalcinosis in children with hypophosphatemic rickets treated with orally administered phosphate and vitamin D, we studied five such patients, aged 3.7 to 12.3 years, during treatment and again 3 days after it had been discontinued. Treatment was associated with significant increases in mean serum phosphate concentration and urine phosphate/creatinine ratio, from 0.71 to 1.03 mmol/L and from 3.61 to 9.42 mmol/mmol, respectively. Significant correlation was found between urine phosphate/creatinine and oxalate/creatinine ratios (r = 0.670; p less than 0.01); however, the mean urine oxalate/creatinine ratio of 65.0 mumol/mmol while patients were taking phosphate orally was not significantly different from the ratio of 59.0 mumol/mmol when treatment was discontinued. Kidney biopsy specimens from three of the patients showed that the renal calcifications were located mainly intratubularly and were composed exclusively of calcium phosphate. In a further investigation of the nature of phosphate-induced nephrocalcinosis, six 6-week-old male Hyp mice, the murine analog of the human disease, received oral phosphate therapy with drinking water for 48 days; six others served as control animals. Mice in the experimental group excreted more phosphate (p less than 0.001) and less calcium (p less than 0.01) than control mice did, and medullary nephrocalcinosis, with a high kidney calcium content, developed (p less than 0.001). Histologic sections showed that the renal calcifications were located intratubularly and were composed of calcium phosphate. We conclude that, both in children with hypophosphatemic rickets and in the Hyp mouse, the development of nephrocalcinosis is associated with high oral phosphate intake and subsequent deposition of calcium phosphate precipitates in the kidney.

Animals↗
PubMed1992

Altitude retinopathy on Mount Everest, 1989.

The authors studied prospectively the incidence of and risk factors for high altitude retinal hemorrhages among 14 members of the 1989 American Everest Expedition. All subjects had comprehensive eye examinations and fundus photography performed at sea level before the expedition and again at the Mt. Everest Base Camp after 6 weeks of exposure to altitudes between 5300 and 8200 meters. Asymptomatic intraretinal hemorrhages were found in five eyes of four climbers. An additional eye of one of these climbers had a central retinal vein occlusion with vitreous hemorrhage, which reduced visual acuity to counting fingers. Higher baseline intraocular pressure and use of nonsteroidal anti-inflammatory drugs were found to be significant risk factors for development of altitude retinopathy.

Acclimatization↗
PubMed1992

Failure of a single postpartum prostaglandin treatment to improve the reproductive performance of dairy cows.

A study was conducted to evaluate the effects of postpartum prostaglandin treatment on reproduction in 3 seasonal calving dairy herds. Recently calved lactating dairy cows were paired on herd, age, calving date and previous production index. One cow in each of the 196 pairs received a single intramuscular injection of 25 mg of the prostaglandin analogue, dinoprost, between 14 and 28 days after calving. Subsequent reproduction was monitored. Within each herd and overall, there was no significant effect of treatment on the intervals from calving to first service, mating start date to first service, calving to conception, mating start date to conception and first service to conception. Treatment also had no significant effect on 21-day submission and pregnancy rates, on the proportion of each group not pregnant at the end of mating, and on first service pregnancy rates. Responses to treatment did not vary between cows calving within 50 days of mating start date and earlier calving cows or between cows aged less than 5 years and older cows.

Animals↗
PubMed1991

Determination of pyridoxamine 5'-phosphate in human blood plasma.

Pyridoxamine 5'-phosphate in 18 microliters of human capillary blood plasma is determined by catalytic amplification using the apoenzyme of aspartate aminotransferase. Prior isolation from interfering substances is accomplished by employment of a cation exchange resin in batch operation. The procedure consists of the following stages. Stage I, denaturation of proteins. Trichloroacetic acid is used to precipitate plasma proteins and liberate any bound coenzyme. Dilute NaCl is added to expand the volume thus minimizing coenzyme entrapment in the precipitate. Stage II, isolation of the coenzyme. A sulfonated polystyrene ion exchange resin is used inside a centrifugal filter. Pyridoxamine 5'-phosphate in the supernatant from Stage I adsorbs to the resin. Pyridoxal 5'-phosphate, other organic phosphates, and Pi are removed by centrifugation. Rinsing with dilute NaBH4 destroys traces of pyridoxal 5'-phosphate and washes off residual inhibitors. Pyridoxamine 5'-phosphate is then desorbed with NaOH and Tris buffer and recovered by centrifugation. Stage III, reconstitution and assay. The desorbate from Stage II is incubated with excess apoenzyme. Specific activity of the reconstituted enzyme is measured. Interpolation from a standard curve relating enzyme specific activity and pyridoxamine 5'-phosphate concentration yields the plasma level of the cofactor. Approximately 3 h are required to carry out the procedure. Much of the coenzyme was found not be assayable if plasma was refrigerated overnight or if whole blood was left standing at room temperature for a few hours. The degradation was arrested with freezing at -80 degrees C. In a 13-day experiment involving a healthy subject, sharp rises of plasma pyridoxamine 5'-phosphate were found to occur in response to small doses of oral vitamin B6.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Intracapsular lens delivery during attempted extracapsular cataract extraction. Association with capsulorrhexis.

Continuous circular tear capsulotomy, or capsulorrhexis, has become a popular technique in cataract extraction, especially in phacoemulsification. The authors report on six cases from five different surgeons at three institutions, in which the entire lens was inadvertently delivered on attempted expression of the nucleus after circular capsulorrhexis. In one case, scanning electron microscopy suggests that the smooth edge of a small, closed, capsular tear is not capable of controlled extension to allow nuclear egress. Therefore, superior radial anterior capsular relaxing incision is recommended when circular capsulorrhexis is used in extracapsular cataract extraction.

Aged↗
PubMed1991

Laboratory testing in pet avian medicine.

The importance of employing laboratory diagnostics in the examination of avian patients cannot be overemphasized. The physical examination alone is grossly insufficient. Many avian illnesses do not display external signs, and laboratory work is imperative in detecting them. Only after the assessment of various laboratory parameters can an examination be considered complete.

Animals↗
PubMed1991

Branhamella catarrhalis colonization of exposed nylon sutures.

A 63-year-old man who had uncomplicated cataract surgery four years previously complained of having redness, blurred vision, and photophobia in his right eye for one week. Examination revealed numerous exposed nylon sutures with peculiar leaf-like, white deposits surrounding them, associated with underlying conjunctival leukocytic infiltration. Smears of the adherent material showed gram-negative diplococci and cultures produced heavy growth of Branhamella catarrhalis. Removal of the offending sutures and fortified topical antibiotic therapy resolved the ocular inflammation. The unique form in which this infection presented is a reminder that ocular surgical patients deserve long-term follow-up for problems like exposed sutures.

Anti-Bacterial Agents↗
PubMed1989

Autosomal recessive form of connatal Pelizaeus-Merzbacher disease.

We report on a brother and sister with the connatal form of Pelizaeus-Merzbacher disease. This rare degenerative disease of white matter is reported to be transmitted as an X-linked recessive with an occasional affected female. Some authors have suggested that an autosomal recessive form exists. When this family is analyzed with other families in the literature, both X-linked and autosomal recessive inheritance must be considered.

Child, Preschool↗
PubMed1989

Keratography as a guide to selective suture removal for the reduction of astigmatism after penetrating keratoplasty.

After penetrating keratoplasty in 52 eyes, keratography refraction and keratometry were used to select appropriate interrupted sutures for removal in order to reduce astigmatism. All eyes had one continuous and either 12 or 16 interrupted nylon sutures. The keratographs were examined retrospectively and separated into six groups on the basis of similar mire patterns. The removal of single sutures associated with three of these patterns reduced astigmatism by the following average amounts: symmetrical oval pattern, 0.44 diopters (D); D-shaped oval pattern, 2.07 D; and focal indentation pattern, 6.60 D. The other three patterns--mildly disrupted mires, incomplete mires, and uninterpretable mires--did not allow quantification of results. Examples of these keratographic patterns are presented and recommendations are made for their use in the management of astigmatism following penetrating keratoplasty.

Astigmatism↗
PubMed1988

Paediatric oncology information pack for general practitioners.

An information pack covering important aspects of paediatric oncology has been developed for general practitioners. Sixty general practitioners who received the information pack found that it helped them in managing children with neoplastic disease and their families. The pack has also improved communications between the oncology unit and general practitioners. Similar packs could be produced by paediatricians working in other specialties.

Child↗