Extraction of AZT and dideoxynucleosides by rat prostate but not testis.
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Animals↗
Biomedical subjects
R Sakiyama
Publications and source records attributed to R Sakiyama.
Influx of testosterone-binding globulin (TeBG) and TeBG-bound sex steroid hormones into rat testis and prostate.
The availability of testosterone and estradiol to Sertoli and prostate cells is dependent upon 1) the permeability properties of the blood-tubular barrier (BTB) of the testis or prostate cell membrane, and 2) sex steroid binding to plasma proteins, such as albumin or testosterone-binding globulin (TeBG). Sex steroid influx into these tissues was studied after in vivo arterial bolus injections of [3H]testosterone or [3H]estradiol in anesthetized rats. Both testosterone and estradiol were readily cleared across the BTB or prostate cell membrane in the absence of plasma proteins and in the presence of human pregnancy serum, in which testosterone or estradiol are 80-95% distributed to TeBG. The extravascular extraction of [3H]TeBG across the BTB or prostate plasma membrane [73 +/- 2% (+/- SE) and 92 +/- 9%, respectively] was significantly greater than extraction of [3H]albumin or other plasma space markers and indicative of a rapid first pass clearance of TeBG by Sertoli or prostate cells. In summary, these studies indicate that 1) testosterone and estradiol are readily cleared by Sertoli and prostate cells; 2) albumin- and TeBG-bound sex steroids represent the major circulating pool of bioavailable hormone for testis or prostate; and 3) the TeBG-sex steroid complex may be nearly completely available for influx through the BTB or prostate plasma membrane.
Animals↗
Common thyroid disorders.
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Euthyroid Sick Syndromes↗
Silent thyroiditis.
Silent thyroiditis is an increasingly recognized cause of transient thyrotoxicosis. Inflammatory destruction of thyroid follicles results in release of preformed thyroxine and triiodothyronine. Patients present with symptoms of thyrotoxicosis, but unlike subacute thyroiditis, lack thyroid pain or tenderness. The thyrotoxic state spontaneously resolves in 2 to 12 weeks at which time the patient either returns to a euthyroid state or passes through a transient hypothyroid phase. Diagnostic laboratory findings include elevations of thyroxine and triiodothyronine and a markedly depressed radioactive iodine uptake. It is imperative for the primary care physician to distinguish silent thyroiditis from chronic causes of hyperthyroidism, eg, Graves' disease, since treatment must be palliative rather than definitive. Long-term prognosis is usually excellent.
Family Practice↗
Restricted transport of vitamin D and A derivatives through the rat blood-brain barrier.
The present studies measure the transport of retinol, retinoic acid, 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], and 25-hydroxyvitamin D3 [25-(OH)D3] through the rat brain capillary endothelial wall, i.e., the blood-brain barrier (BBB). The vitamin A and D derivatives bind both to albumin and to specific high-affinity binding proteins in plasma. In the presence of physiologic concentrations of plasma proteins, the extraction by brain of all four compounds was 5% or less.
Animals↗
Posttraumatic epilepsy and CT scan.
Among 83 head-trauma cases examined by CT scan in a later year, 41 were included in a seizure group of those who clinically showed late epilepsy and who obviously showed epileptic discharge such as spike or spike and wave in EEG after trauma, and 42 were included in a nonseizure group of those who had some sequelae such as abnormal findings in EEG or neurologic defects: the CT findings of these 83 cases were collected and compared with clinical findings, EEG, and other data. The CT findings of these cases were divided into five groups: (A) a normal group; (B) a group showing partial or unilateral ventricular dilatation; (C) a group showing porencephaly in the cerebral parenchyma; (D) a group suspected of cortical atrophy; (E) a group of other cases. Group D contained 44.3% of the cases, and was the largest group; the frequency of seizure was highest in Group C. The CT classification reveals the contradiction of the conventional definition of posttraumatic epilepsy and also poses some problems concerning the disease. CT scan is mostly applied to head trauma in the acute stage, and as for trauma in the chronic stage there are a few reports on chronic subdural hematoma and post-traumatic hydrocephalus. We noticed posttraumatic epilepsy among the sequelae of trauma, and then analyzed CT findings of the epilepsy: the results are reported here.
Adolescent↗