Drug effects on aqueous humor formation and pseudofacility in sympathectomized rabbit eyes

The effects of the adrenergic agonists, norepinephrine, epinephrine, isoproterenol and phenylephrine have been assessed on aqueous humor formation rate (AHFR) and pseudofacility (C_p8) in the ganglionectomized rabbit eye. The drug concentrations used were 0·1% as a topical drop. Norepinephrine increased AHFR by 50% and doubled C_p8 with no change in intraocular pressure (IOP). Epinephrine caused a 10% decrease in AHFR and an increase in C_p8, also with little change in IOP. Isoproterenol decreased AHFR and increased C_p8, with a fall in IOP. Phenylephrine reduced AHFR and C_p8 was unchanged, yet IOP barely changed. Together with in vitro data which indicated that ciliary epithelial permeability does not increase after ganglionectomy the data can be used to estimate other effects of the drugs. It is apparent that ganglionectomy alone must cause an increase in the perfused area of ciliary epithelium and that two major effects of the drugs employed are on true outflow facility and on blood flow through the anterior uvea.     

The effect of castration, thyroidectomy and haloperidol upon the turnover rates of dopamine and norepinephrine and the kinetic properties of tyrosine hydroxylase in discrete hypothalamic nuclei of the male rat

Adult male rats were either castrated, thyroidectomized, or treated with haloperidol and the rates of turnover of dopamine (DA) and norepinephrine (NE) in the median eminence (ME), the arcuate and dorsomedial nuclei of the hypothalamus were estimated from the rate of decay of DA and NE concentrations as determined by radioenzymatic assay following blockade of catecholamine synthesis byalpha-methyl-p-tyrosine. The ME of animals similarly prepared was also examined for changes in the total activity and kinetic properties of tyrosine hydroxylase (TH). Four days following the administration of haloperidol (400 μg/kg) or 10 days after castration, there was a significant increase in the rate of turnover of DA but not NE in the ME accompanied by an increase in the V_max but notK_m for substrate or cofactor of TH. Furthermore, the administration of haloperidol to hypophysectomized rats also significantly increased the TH activity in the ME, indicating that such changes may occur independently of any changes in serum prolactin levels. Ten days after thyroidectomy, or three weeks after treatment with propylthiouracil, there was a significant increase in the turnover rate of DA in both the ME and dorsomedial nucleus but not in the arcuate nucleus. No changes in the turnover rates of NE in anu of the three areas were observed following thyroidectomy. In the ME, the increase in turnover of DA was accompanied by an increase in the total TH activity (V_max) as well as a decrease inK_m for tetrahydrobiopterin but not tyrosine. From these results 4 conclusions were drawn: (1) following haloperidol, castration, and thyroidectomy there are increases in the activity of dopaminergic terminals within the ME; (2) castration, haloperidol and thyroidectomy may influence the activity of dopaminergic terminals within the ME by different mechanisms; (3) changes in tyrosine hydroxylase and turnover of catecholamines within the ME may occur independently of changes in prolactin levels; and (4) local recurrent afferent circuits may exist in the arcuate nucleus region of the hypothalamus.     

A single case experimental design comparing two memory notebook formats for a man with memory problems caused by traumatic brain injury

There is extensive literature demonstrating that restoration of memory is not a realistic goal for rehabilitation and that efforts are more effective if focused on developing compensatory strategies. This paper compares two formats of memory notebook using an ABAB single-case experimental design with a 46-year-old man with a history of head injury. Results revealed significantly better performance on a series of prospective memory tasks for the "modified" notebook. The study highlights the importance of tailoring the diary to the patient's needs and giving careful consideration to the way in which the diary is introduced.     

Cognitive aspects of anxiety and depression in the elderly

Although older adults represent the fastest-growing segment of the population, we have just begun to understand the nature of anxiety and depression in this age group. In this review, current models of anxiety and depression are examined, with consideration of similarities and differences between data drawn from younger and older adults. Studies that look at the content of specific cognitions associated with anxiety, depression, and cognitive processes, such as attention and memory, are examined. Consideration is given to areas for clinical application and future research.     

A case of PHACE syndrome

A young girl with PHACE syndrome presented with a posterior fossa malformation, a segmental telangiectatic right facial haemangioma, a novel aortic arch anomaly, a congenital right fourth cranial nerve palsy (not previously described in this syndrome) and Horner's syndrome. Hydrocephalus was limited to the intrauterine period and detection of the cardiovascular anomalies was a direct result of recognition of this syndrome. She has received laser treatment for the haemangioma and is awaiting surgical correction of her cranial nerve palsy.     

Embryonic cerebellar granule cells are resistant to necrosis induced by homocysteine

Hyperhomocysteinemia is a risk factor for a range of neurodegenerative conditions, yet its effects in the developing nervous system have been poorly elucidated. We studied the in vitro response of cerebellar granule neurons (CGCs) to homocysteine. We have shown that embryonic CGCs are resistant to homocysteine-induced neurotoxicity, whilst postnatal CGCs are not. This is the first demonstration of a neuronal population undergoing a developmental switch in their response to homocysteine. Greater understanding of this change may have important implications for both neurodegenerative conditions and neurodevelopmental disorders.     

Multiphasic helical CT diagnosis of early medullary and papillary necrosis

PURPOSE: The feasibility of identifying early manifestations of renal papillary necrosis (RPN) and medullary necrosis (RMN) on multiphasic helical CT, leading to prompt treatment for the causative conditions, and its impact on reducing the incidence of late-stage RML and RPN, was investigated. PATIENTS AND METHODS: Sixty-eight patients (35 male, 33 female) aged 19 to 88 years were examined by multiphasic helical CT for complaints of microscopic hematuria (N=49), macroscopic hematuria (N=2), bacteriuria (N=45), pyuria (N=10), fever (N=15), and flank pain (N=27). Preenhancement, arterial corticomedullary, parenchymal, and excretory phase scans generated 1.25 to 7-mm-thick slices. Follow-up CTs were performed at 1 month (N=62) and 3 months (N=58). RESULTS: While the attenuation coefficients of areas suspect for RMN and RPN were similar on preenhancement CT, they differed substantially on the arterial corticomedullary phase (lesions 55 HU mean; normal medulla 120 HU mean) and parenchymal phase (lesions 58 HU mean, normal medulla 210 HU mean). Investigation for predisposing conditions identified diabetes in 18 patients, upper urinary-tract infections in 48, sickle-cell disease or trait in 17, urinary obstruction in 7, and cirrhosis of the liver in 1. On follow-up examinations, enhancement had normalized in 26 compromised areas of 14 patients at 1 month, and 47 areas (23 patients) at 3 months, remained stationary in 28 patients at 1 month and 9 at 3 months, and progressed in 20 at 1 and 26 at 3 months (P<0.001; Fisher's exact test). Patients (N=35) treated for underlying conditions causing ischemia showed reperfusion in 12 cases at 1 month and 20 at 3 months, while of the untreated patients (N=10), none showed reperfusion, and all lesions increased in size. CONCLUSIONS: Multiphasic helical CT is recommended for identification of RMN and RPN at a stage when effective treatment of underlying causative conditions can arrest or reverse the process of devascularization and prevent loss of medullary tissue.     

Multiphasic helical CT criteria for differentiation of recurrent neoplasm and desmoplastic reaction after laparoscopic resection of renal mass lesions

BACKGROUND AND PURPOSE: Differentiation of recurrent neoplasm and desmoplastic reaction following laparoscopic resection of renal mass lesions poses a problem. The usefulness of multiphasic helical CT-generated criteria based on enhancement and morphologic characteristics was investigated. PATIENTS AND METHODS: The findings in 5 female and 12 male patients aged 29 to 68 years having renal-cell carcinoma (11-38 mm; N = 15) or solitary angiomyolipomas (N = 2) treated by laparoscopic resection (N = 15) or open segmental surgery (N = 2) were analyzed. Multiphasic helical CT was performed in the preenhancement, arterial corticomedullary, parenchymal, and excretory phases generating 2.5- to 7-mm slices. RESULTS: Both recurrent neoplasms showed median postcontrast enhancement of 119 HU in the arterial corticomedullary phase; the median enhancement of desmoplastic masses was 48 HU. In the parenchymal and excretory phase, recurrent neoplasms showed progressive loss of enhancement, whereas desmoplastic lesions sustained enhancement at about the same level. Recurrent neoplasms presented a defined mass with characteristic spiculation, whereas desmoplastic reaction was characterized by an ill-defined mass with spidery projections extending to abutting fat and residual fascial planes. On 2- to 3-month follow-up scans, recurrent neoplasms showed progressive increases in size and desmoplastic reaction a sharp decrease. CONCLUSION: Enhancement of the mass at the operative site on arterial corticomedullary-phase CT to >90 HU strongly suggests recurrent renal-cell carcinoma, while progressive decrease in size on 1- to 3-month follow-up CT suggests a desmoplastic reaction.     

Postoperative mortality after nontraumatic lower extremity amputation in patients with renal insufficiency

Mortality rates after lower extremity amputation are extremely high among dialysis patients. However, the impact of milder degrees of renal insufficiency on death rates after lower extremity amputation has not been carefully examined. In this study, the authors used data from the Department of Veterans Affairs' National Surgical Quality Improvement Program (NSQIP) to measure the association between renal dysfunction and 30-d mortality after nontraumatic amputation adjusted for confounders. The study population consisted of 16,994 patients undergoing their first NSQIP recorded amputation from January 1, 1994 through September 30, 2001. Thirty-five percent of all cohort patients had at least moderate renal insufficiency, and 52% of all postoperative deaths occurred in this group. Postoperative mortality was 9% in patients with moderate renal insufficiency, 15% in patients with severe renal insufficiency, and 16% in dialysis patients, compared with 6% in patients with normal or mildly reduced renal function. Renal insufficiency remained associated with death after adjustment for confounders (adjusted odds ratio [OR] 3.36, 95% confidence interval [CI] 2.75 to 4.10 [dialysis patients]; OR 2.54, CI 2.06 to 3.14 [severe renal insufficiency]; and OR 1.52, CI 1.32 to 1.76 [moderate renal insufficiency]). In conclusion, even moderate renal insufficiency is independently associated with postoperative death after lower extremity amputation. This finding highlights the need for a targeted approach to improving the care of patients with renal insufficiency undergoing lower extremity amputation.