Vitamin D deficiency in individuals with a spinal cord injury: a literature review.

STUDY DESIGN: Literature review of studies investigating vitamin D status in individuals with a spinal cord injury (SCI). OBJECTIVES: Prevalence of vitamin D deficiency seems to be high in the general population. Little is known regarding such a deficiency in individuals with a SCI. This review aimed to examine the literature that investigated vitamin D status in this population. SETTING: Switzerland. METHODS: A literature review was performed to investigate the prevalence of vitamin D deficiency in individuals with a SCI and to determine the factors leading to deficiency. RESULTS: Sixteen studies which met all the inclusion criteria were identified. All of these studies assessed total serum 25-hydroxy vitamin D status in individuals with an acute or chronic SCI. Overall, the prevalence of vitamin D deficiency or insufficiency seems to be high (range: 32-93%) in this population compared with that in able-bodied persons. The main factors are immobility, low physical activity and bedrest, and therefore not enough exposure to sunlight. In addition, age, skin pigmentation, lesion level, occurrence of pressure ulcers, body mass index, season and latitude appeared to be further determinants for vitamin D deficiency. In athletes, playing their sport indoors or outdoors may have an additional role in developing vitamin D deficiency. CONCLUSION: The available studies suggest that individuals with a SCI are at increased risk for vitamin D insufficiency/deficiency. Nutritional strategies and supplementation recommendations need to be developed to prevent these conditions in SCI. SPONSORSHIP: Not applicable.

Vitamin D deficiency in Swiss elite wheelchair athletes.

STUDY DESIGN: This is a retrospective analysis of total serum 25-hydroxyvitamin D (25[OH]D) in Swiss elite wheelchair athletes. OBJECTIVES: The aim was to investigate the occurrence of vitamin D deficiency in Swiss elite wheelchair athletes over the whole year and to detect differences between winter and summer months, and between indoor and outdoor athletes. SETTING: This study was conducted in Switzerland. METHODS: A total of 164 blood samples from 72 Swiss elite wheelchair athletes (mean±s.d.: age 32±13 years) were analyzed for total serum 25[OH]D. All participants were members of the national team in their discipline. The following disciplines have been included: rugby, athletics, cycling, tennis, ski alpine, curling and basketball. According to general guidelines, insufficient vitamin D status was defined between 50 and 75 nmol l-1, deficiency below 50 nmol l-1 and severe deficiency below 27.5 nmol l-1. RESULTS: In all, 73.2% of all samples showed an insufficiency/deficiency in vitamin D status. Total serum 25[OH]D was significantly higher during summer compared with winter months (69.5±21.4 nmol l-1 vs 51.5±21.9 nmol l-1; P<0.001). Indoor sports showed a higher amount of vitamin D insufficiency/deficiency (80.9%) than outdoor sports (70.1%), with a significantly higher 25[OH]D concentration in outdoor sports (P=0.042). CONCLUSION: A high percentage of vitamin D deficiency was found among Swiss elite wheelchair athletes. Conclusively, we recommend supplementation with vitamin D-especially during winter-to prevent a deficiency and an impairment of performance.

Reliability of a 3-min all-out Arm Crank Ergometer Exercise Test.

The 3-min all-out test is a well-established exercise test developed for cycling ergometry. However, no such test exists in arm cranking. Thus the aim of this study was to investigate the test-retest reliability of a 3-min all-out exercise test on an arm crank ergometer. 21 healthy participants (9 male and 12 female, age 34±11 years, body mass 69.6±11.1 kg and height 175.5±6.9 cm) twice performed a 3-min all-out exercise test on an arm crank ergometer separated by 7 days. Peak power (PP), mean power (MP), fatigue index (FI), time to peak (TTP) and total work (TW) were assessed to detect test-retest reliability. PP, MP, FI and TW showed an excellent intra-class correlation coefficient (ICC) ranging from 0.940 to 0.984. Only TTP showed very low reliability with an ICC of 0.379. The results from this test-retest analysis showed that all parameters except the TTP were highly reliable in a 3-min all-out exercise test on an arm crank ergometer in able-bodied participants.

Biopharmaceutical comparison of two levothyroxine sodium products.

The relative bioavailability and therapeutic equivalence of two brands of levothyroxine sodium tablets, Levothroid and Synthroid, were compared in patients who had been receiving long-term levothyroxine replacement therapy. Eighteen patients with primary hypothyroidism were randomly assigned to receive therapeutic dosages of Levothroid or Synthroid for 43 days and then were switched to the opposite product for 43 more days. The pharmacokinetic profiles of the two drugs were evaluated on days 43 and 86 by analyzing blood samples drawn at various intervals after the final dose. Relative bioavailability was determined by comparing the absorption profiles and areas under the serum concentration-time curves (AUCs) of total and free serum thyroxine. In addition, the potency of the levothyroxine sodium tablets was determined by high-performance liquid chromatography. The time to reach maximum concentration and the maximum concentration of total thyroxine after treatment with Levothroid did not differ significantly from those after treatment with Synthroid. The mean +/- S.D. AUC of total thyroxine after Levothroid administration (2339 +/- 404 pg.hr/mL) was slightly but significantly higher (p = 0.047) than that following Synthroid (2169 +/- 422 pg.hr/mL). However, the main index of biological activity, thyrotropin concentration, did not differ significantly between the two products. All tablets tested were within the stated potency requirements of the USP. The AUC of total serum thyroxine and the serum thyrotropin concentration after long-term replacement therapy with Levothroid or Synthroid indicate that any differences in bioavailability between the two products are clinically unimportant and that the two products are therapeutically interchangeable.

Medullary thyroid cancer and Graves' disease.

A focus of medullary thyroid cancer was found at frozen section analysis of tissue from a patient with Graves' disease undergoing thyroid lobectomy. An increased incidence of papillary-follicular thyroid cancer has been noted in Graves' disease. This report describes the unique association of medullary thyroid cancer and Graves' disease.

Extensive extraosseous localization of bone imaging agent in a patient with renal failure and rhabdomyolysis accompanied by combined hypercalcemia and hyperphosphatemia.

Four sequential Tc-99m pyrophosphate (PYP) imaging studies were performed in a 28-year-old man with high fever and exudate pharyngitis associated with renal failure. Radiotracer localization in the left ventricle (LV), lungs, kidneys, and skeletal muscles were seen in two, initial imaging studies. In the second and third imaging studies, area of increase in activity was seen in the left-sided bowel. In studies done two months later (in the third study), the radioactivity in the skeletal muscles was no longer seen. Studies obtained nine months (in the fourth study) after the first imaging showed less radiotracer localization in the LV, lungs, and kidneys as compared to that seen in the initial study. Myocardial necrosis and microcalcification were proved by LV biopsy. The exact mechanism of extraosseous bone-imaging agent localization is unknown. However, this phenomenon may be related to renal failure, rhabdomyolysis, hypercalcemia, hyperphosphatemia, or elevated parathyroid hormone. The Tc-99m PYP imaging study is useful and sensitive in the detection of extraosseous tissue calcification and monitoring of the disease process.

Annular pancreas associated with diffuse chronic pancreatitis.

A patient with longstanding diabetes and renal failure presented with painless vomiting due to duodenal obstruction was found to have an annular pancreas. Initial operative evaluation, later pathologically confirmed, demonstrated involvement of not only the annulus, but also the entire gland by diffuse atrophic chronic pancreatitis. We speculate on the possible influence of the underlying diabetes and renal disease on the pathogenesis of the unusual generalized chronic inflammatory changes and the precipitation of duodenal obstruction in this patient.

Multiple endocrine neoplasia type IIb: a description of several patients and review of the literature.

Our experience exemplifies the varied clinical presentations of patients with MEN IIb. This syndrome may be familial or sporadic, and clinical stigmata may be identifiable in infancy, particularly the characteristic facies and the appearance of ganglioneuromas. First-degree relatives of affected propositi and individuals with other stigmata of the syndrome should be screened carefully and repeatedly for both medullary thyroid carcinoma and pheochromocytoma. The availability of sensitive screening tests may permit detection of C-cell hyperplasia of the thyroid and adrenal medullary hyperplasia before the development of malignancy or hemodynamic consequences of pheochromocytoma. Early detection of these thyroid and adrenal disorders will permit early surgical intervention.

Ethchlorvynol pharmacokinetics during long-term administration in a patient with hyperlipidemia and hypothyroidism.

A 33-year-old obese, hypothyroid, white male with several medical problems was admitted to University Hospital in September 1984 for treatment of drug intoxication. Admitting medications included ethchlorvynol in addition to other central nervous system depressants. Initial serum concentrations were reported at 70 micrograms/ml in this somnolent yet totally conscious adult. Established therapeutic concentrations are 2-8 micrograms/ml, with toxic exceeding 20 micrograms/ml. A tolerance phenomenon seemed evident. Serum ethchlorvynol concentrations were monitored daily during early hospitalization and continued to be substantially greater than reported toxic concentrations. Kinetic values were as follows: total body clearance 9.92 ml/min, volume of distribution 68.0 liters, and half-life 78 hours. These values are unique in that they were calculated from a patient who had not suffered an acute overdose, thereby differing markedly from previously published values. The influence of hypothyroidism and hyperlipidemia on these markedly different values appears to be significant. Ethchlorvynol should probably be added to the list of drugs influenced by thyroid disease.

Adrenal insufficiency following unilateral adrenalectomy: a case report.

We report a case of resection of a unilateral adrenal pseudocyst that precipitated life-threatening adrenal insufficiency. The patient had extremis unresponsive to pressor agents in the immediate postoperative period. Hydrocortisone administration produced temporary resolution and a cosyntropin-stimulation test confirmed adrenal insufficiency. Because of the presence of an adrenal mass, the preoperative evaluation included a formal endocrinological evaluation. Thus, we were able to document the occurrence of acute postoperative primary adrenal insufficiency.

Evaluation of the hypercalcemic patient.

Malignancy is the most common cause of hypercalcemia, which may result from direct involvement of bone or from local or distant production of substances that enhance bone resorption. The recognized incidence of primary hyperparathyroidism has increased greatly since the advent of automated biochemical screening. A single parathyroid adenoma is most frequently the cause. Sarcoidosis commonly results in hypercalciuria but seldom causes sustained hypercalcemia. Increased production of 1,25-dihydroxycholecalciferol leads to hyperabsorption of calcium and enhanced bone resorption.

Carboxyl-terminal fragments of human parathyroid hormone in parathyroid tumors: unique new source of immunogens for the production of antisera potentially useful in the radioimmunoassay of parathyroid hormone in human serum.

We have found large quantities of immunoreactive carboxyl-terminal fragments of human parathyroid hormone )hPTH) in a previously discarded fraction [the 7.5% trichloroacetic acid (TCA)supernate] generated during extraction of intact hPTH from hyperfunctioning parathyroid tissue by the urea-TCA procedure. It is well established that serum RIAs directed toward the carboxyl-terminal region of hPTH are superior to those directed toward the amino-terminal region in the differential diagnosis of patients with suspected chronic parathyroid dysfunction. However, antisera that react with the carboxyl-terminal region of hPTH are not yet available for general use for these assays because of a lack of suitable hPTH immunogens. We immunized seven guinea pigs and two goats with the desalted 7.5% TCA supernate (containing about 2% carboxyl-terminal hPTH fragments); three of the guinea pigs and one goat produced high affinity antisera with predominant specificity for the carboxyl-terminal region of PTH. One of the guinea pig antisera had affinity for hPTH equal to that of our laboratory's best antiserum (GP1M) used in diagnostic RIAs for serum PTH. The use of this byproduct fraction as an immunogen should permit a large scale immunization program in large animals to provide standardized, species-and sequence-specific antisera potentially useful in RIAs for diagnosis of parathyroid disease.

Immunoheterogeneity of parathyroid hormone in venous effluent serum from hyperfunctioning parathyroid glands.

The immunoreactive parathyroid hormone (iPTH) in the plasma of hyperparathyroid man consists largely of carboxyl (COOH)-terminal fragments of the hormone. Although these fragments have been thought to arise principally or solely from peripheral metabolism of intact human PTH {hPTH(1-84)} secreted from the parathyroid gland, there is disagreement about the source of iPTH fragments in vivo. To reexamine this question, we fractionated peripheral and thyroid or parathyroid venous effluent sera from four patients with primary hyperparathyroidism using a high-resolution gel filtration system (Bio-Gel P-150 columns run by reverse flow). The column effluents were analyzed using two PTH radioimmunoassays, one directed toward the amino(NH(2))-terminal region of the molecule, the other toward the COOH-terminal region. In all four thyroid or parathyroid venous effluent sera studied, iPTH was 9-180 times higher than in peripheral serum from the same patient; after fractionation, hPTH(1-84) accounted for only a portion of the total iPTH (35-55% with the assay directed toward the COOH-terminal region of hPTH, >90% with the NH(2)-terminal directed assay.) The remaining iPTH eluted from Bio-Gel P-150 after hPTH(1-84) as NH(2)-or COOH-terminal hPTH fragments. These results suggest that parathyroid tumors secrete large quantities of hPTH fragments. Based on estimates of their molar concentrations in serum, tumor-secreted COOH-terminal hPTH fragments could account for most of these peptides in peripheral serum if their survival times were, as estimated by several other workers, 5-10 times that of hPTH(1-84). We conclude that, in contrast to published information, secretory products of hyperfunctioning parathyroid tissue are probably a major source of serum PTH immunoheterogeneity.