Biomedical subjects
H Johnston
Publications and source records attributed to H Johnston.
Concentrations and total daily output of micronutrients in breast milk of mothers delivering preterm: a longitudinal study.
The number of preterm infants fed their own mother's milk appears to be increasing as a result of information suggesting certain benefits over milk from human milk banks or proprietary formulas. It is also apparent that the nutritional requirements of term and preterm infants differ. Thus, the finding of various deficiencies in small preterm infants indicates that studies which examine the nutrient content of milk from mothers who deliver prematurely are important to aid in suggesting appropriate supplementation. In order to provide appropriate recommendations, nutrient content must be assayed during the period of exclusive milk feedings. Accordingly, the concentrations and total daily output of breast milk zinc and copper, and vitamins A, C, and E, were examined in a group of 13 mothers delivering at or before 32 weeks gestation. Collections of a total 24-h output were obtained every 7 days for the first 7 weeks after delivery. Concentrations of all micronutrients were similar to those reported previously during the first 5 weeks of lactation. Most striking, however, was the progressive decline in total output as well as concentration of zinc. After the first 2 weeks of lactation, levels of copper and vitamins A, C, and E were not affected by the duration of lactation. There was substantial variation between mothers in daily output of all the micronutrients. The low output of these micronutrients suggests that some attempt should be made at monitoring the mineral and vitamin status of small preterm infants fed exclusively human milk for the first 3 months of life.(ABSTRACT TRUNCATED AT 250 WORDS)
Needle biopsy in the assessment and management of hypofunctioning thyroid nodules.
Needle biopsy of hypofunctioning solitary thyroid nodules provides direct diagnostic information which would be otherwise obtainable only by surgery. The technique is safe and cost-effective. It provides a high diagnostic yield. It is also useful in planning surgery and reducing dependence on frozen-section diagnosis, which is often difficult with thyroid nodules. Technical and interpretative precautions are discussed. Of 192 patients undergoing this procedure, a satisfactory specimen was obtained in 95 percent. Needle aspiration biopsy (fine needle) was done in 110 patients with good cytologic correlations. Of 52 glands subsequently excised, carcinoma was present in 22 (42 percent). The preoperative diagnosis had been made in 19 (86 percent) of the latter group. This procedure is recommended for consideration in the assessment and management of hypofunctioning thyroid nodules.
Eosinophilic granuloma mimicking a pituitary tumor.
The authors present the case report of a patient in whom hypopituitarism, diplopia, and visual field defects were due to eosinophilic granuloma. Radiographic studies were suggestive of a pituitary tumor and subsequent histological evaluation showed replacement of the anterior pituitary by histiocytic cells. Eosinophilic granuloma should be included in the differential diagnosis of an intrasellar mass.
Unilateral exophthalmos: an unusual presentation of primary hyperparathyroidism.
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Diabetes team teaching utilizes community resources.
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Newly recognized vital nitrogen cycle.
Soil and sea bacteria produce a small amount of nitrous oxide (N(2)O); a small part of this N(2)O is photochemically converted to nitric oxide (NO) in the stratosphere. This process has recently been shown to be the principal source of the active oxides of nitrogen (NO and NO(2)) in the stratosphere. The active oxides of nitrogen catalytically destroy ozone, and NO and NO(2) appear to be a principal factor in the natural ozone balance. Stratospheric ozone is the only effective shield for the surface of the Earth against the harsh ultraviolet radiation between 300 and 250 nm. Thus, soil bacteria indirectly control the intensity of ultraviolet radiation reaching the Earth's surface. This subcycle of the major nitrogen cycle involves a relatively small amount of nitric oxide, estimated to be between 0.26 and 1.2 x 10(9) kg of NO per year on a worldwide basis. A recent estimate of the future nitric oxide emission in the stratosphere by the Concord supersonic transport is 0.37 x 10(9) kg/year on a world-wide basis, which is similar to the amount estimated from the natural source.
The influence of anaesthesia and surgery on plasma cortisol, insulin and free fatty acids.
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Continuing education in diabetes. A report of the North Dakota nutrition and diabetes workshops.
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Serum placental alkaline phosphatase in normal pregnancy and preeclampsia.
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Postoperative chemotherapy in children less than 4 years of age with malignant brain tumors: promising initial response to a VETOPEC-based regimen. A Study of the Australian and New Zealand Children's Cancer Study Group (ANZCCSG).
PURPOSE: Postoperative chemotherapy with indefinite postponement of radiation therapy in children < 4 years old with brain tumors was investigated in a multi-institutional study. PATIENTS AND METHODS: From 1991 to 1995, 42 patients aged 3 to 47 months (median 20) with brain tumors were enrolled in a 2-phase chemotherapy protocol: 16 patients had medulloblastoma (MB); 8 had supratentorial primitive neuroectodermal tumor (PNET); 14 had ependymoma; and 4 had other tumors. The initial phase was comprised of 4 courses of the 3-drug regimen: vincristine (VCR), etoposide (VP-16), and intensive cyclophosphamide (CPA) in a previously reported schedule (VETOPEC). The continuation phase was comprised of 2-drug courses: A, CPA + VCR; B, cisplatin + VP-16; and C, carboplatin + VP-16, for a total duration of 64 weeks. RESULTS: Response to VETOPEC was evaluable in 28 patients with postresection residual (25) and/or metastatic (1 M2, 6 M3) tumor. There were 9 complete responses (CR) and 9 partial responses (PR) with a combined CR + PR of 64% (95% confidence interval [CI] 44 to 81). In 12 evaluable patients with MB, CR + PR was 82% (48 to 98); in 6 patients with PNET, 50% (12 to 88); and, in 8 patients with ependymoma, 86% (42 to 99). Of 40 patients eligible for further analysis, 6 remain progression-free at a median of 30 months, 14 are alive at a median of 38 months, 29 have progressed at a median of 7 months (range, 2 to 37 months), and 26 have died. The progression-free and overall survival rates at 36 months are estimated to be 11% (95% CI 1 to 22) and 34% (18 to 50), respectively. CONCLUSIONS: The initial response to the VETOPEC regimen is encouraging and warrants study of further dose escalation. Survival remains poor with current strategies in this high-risk population.
Evaluation of recharge in a small temperate catchment using natural and applied delta 18O profiles in the unsaturated zone.
A water balance study was used for determining recharge rate and mechanisms in the Enler Catchment, Northern Ireland. Here spatially limited data for the water balance resulted in varied calculation of the annual and monthly net infiltration rate. This paper outlines a method whereby high-resolution soil profiles (1 to 2 cm) were obtained from field cores in the upper 2 m of the unsaturated zone using delta 18O of water. These profiles show changes in isotopic composition that range from individual rainfall events to annually integrated cycles of rainfall. Recharge rates were calculated from stable isotope profiles for each of the four main soil types in the study catchment and summed over each area resulting in an average recharge in the range 55 to 70 mm/a, which is comparable with previous findings. Applied isotopic tracer tests were also conducted to evaluate the extent of preferential flow through the two main soil types in the catchment. Rates of water movement found from these experiments show good agreement with natural isotopic profiles; however, evidence suggests that preferential flow is not the dominant process controlling water movement in this catchment. This type of data provides valuable information about recharge rates and mechanisms and may facilitate better prediction of contaminant transport pathways in the vadose zone.
Caring for carers coping with stroke.
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