The histology of nasopharyngeal masses: a comparison between HIV positive and HIV negative patients.

The aim of this study was to compare the histology of nasopharyngeal masses of HIV positive and HIV negative patients and to determine the prevalence of malignancy in nasopharyngeal masses in HIV positive patients. The records of all patients who had nasopharyngeal biopsies performed at the Department of Otorhinolaryngology, Universitas Academic Hospital between January 2006 and December 2011, were reviewed and 151 patients were identified. The HIV status of 110 of these patients was known: 78 (70.9 %) were HIV positive and 32 (29.1 %) were HIV negative. The CD4 count was known in 63 (80.8 %) of the HIV positive patients with the median CD4 count being 275 cells/µl (14-712 cells/µl). Most nasopharyngeal masses in HIV positive patients were benign. Malignancies were significantly more common in the HIV negative group than in the HIV positive group, with six (7.7 %) of the nasopharyngeal masses in the HIV positive group being malignant, while eight (25 %) of those in the HIV negative group were malignant. Most nasopharyngeal masses in HIV positive patients are due to lymphoid hyperplasia. The presence of large cervical lymphadenopathy should alert one to the possibility of a malignancy rather than a benign disease process.

Efficacy of ramipril versus enalapril in patients with mild to moderate essential hypertension.

This double-blind, randomised, cross-over study investigated the antihypertensive efficacy of ramipril and enalapril was completed by 30 patients with mild-to-moderate essential hypertension. After a four-week placebo run-in phase, the patients received either 2.5mg ramipril or 10mg enalapril once daily for four weeks. The dosages were increased to 5mg ramipril and 20mg enalapril for a further four weeks. After a placebo washout phase of four weeks, the patients were crossed over to the alternative treatment. The decrease in average 24-hour ambulatory diastolic blood pressure from week 0 to week 8 was 1.6mmHg greater with ramipril than enalapril (90% confidence interval 0.6-2.7mmHg). The corresponding reduction in for systolic blood pressure was also greater with ramipril than enalapril by 2.4mmHg (90% confidence interval: 0.5-4.2mmHg). For the difference in the drop of 24-hour ambulatory diastolic blood pressure between ramipril and enalapril the lower level of the 90% confidence interval (CI) is above the clinically relevant difference of -3mmHg. This is an indication that ramipril (2.5 and 5mg dose) is at least as effective as enalapril (10 and 20mg dose) in decreasing blood pressure in patients with mild-to-moderate essential hypertension. The duration of adequate antihypertensive effect was relatively long for both ramipril and enalapril; however, ramipril tended to have a more prolonged antihypertensive effect. Ramipril had a higher diastolic and systolic trough/peak ratio than enalapril, resulting in a more uniform antihypertensive effect over the 24-hour treatment period. Both ramipril and enalapril were well tolerated and the two treatment groups had similar safety profiles.

What do mice select for in seeds?

Knowledge of the basis upon which granivores select seeds is crucial to the understanding of granivory. In this study the preferences of three rodent granivores among seeds of 11 plants from the semi-arid Karoo of South Africa were estimated, and related to the physical and chemical attributes of the seeds. Seed weights and calorific, moisture, protein, polyphenol, ash, lipid and silica contents were estimated and cell contents, soluble ash and soluble carbohydrate contents were derived from these values. These attributes were determined for both the intact seeds and the portion of the seed that is ingested by the mice. The efficiency with which mice ingested the seeds (in terms of time and mass) was recorded. All three mouse species ranked the seeds similarly, and the two species for which handling efficiency was measured did not differ in this regard. Preference hierachies were highly correlated with the rate of energy intake, as predicted by optimal foraging theory. There was no correlation between rodent preferences and the gross energy content of the seeds, emphasising the importance of measuring relevant parameters. The energy yield of the seeds calculated here, in conjunction with rodent population energy requirements and dietary data, may be used to estimate potential granivore impact on the seed production of the plant community.

Control of plasma arginine vasotocin in Kelp gulls (Larus dominicanus): roles of osmolality, volume, and plasma angiotensin II.

The physiological roles of plasma osmolality, volume, and angiotensin II (AII) in the control of plasma arginine vasotocin (AVT) have been evaluated in the Kelp gull. Plasma AVT (measured by radioimmunoassay) consistently followed the changes in plasma osmolality induced by dehydration, intravenous (iv) infusion of hypertonic saline, or iv infusion of hypotonic glucose solution. Osmoreceptor control of AVT was further characterized by the stimulatory effect of iv hypertonic mannitol but lack of effect of iv hypertonic urea. A direct volume effect on AVT release was demonstrated during hemorrhage, but blood volume reductions in excess of 10% were required. However, the volume of the extracellular fluid (ECF) compartment does have an important role in modulating the osmotic release of AVT in a way that enables contraction or expansion of ECF to be more expeditiously corrected than would occur if osmoreceptors alone regulated plasma AVT. Any physiological role of plasma AII in the control of plasma AVT is doubtful because after the iv infusion of AII for 60 min at 10, 25, 50, and 100 ng.min-1, only the two highest doses of AII, which produced supraphysiological plasma AII levels, caused elevations of plasma AVT. In addition, the osmotic reactivity of AVT release was not altered by exogenous administration of AII.

Thermoregulatory patterns of two sympatric rodents: Otomys unisulcatus and Parotomys brantsii.

1. The adaptations to an arid environment in two closely related rodent species were investigated. 2. The rate of oxygen consumption (VO2), body temperature (Tb), evaporative water loss and minimal conductance in Otomys unisulcatus and Parotomys brantsii were determined under controlled conditions at ambient temperatures (Ta), ranging from 11-31 C. 3. Physiological features atypical of desert-adapted rodents include a basal metabolic rate higher than predicted by body mass, the low "lower critical temperature" and symptoms of heat stress at 31 degrees C. 4. The low Tb and wide thermoneutral zone recorded for both species are characteristic of desert rodent species. 5. These species' physiological abilities reflect their mesic phylogeny and we suggest that behaviour must play an important role in their survival in semi-arid areas.

Control of renal and extrarenal salt and water excretion by plasma angiotensin II in the kelp gull (Larus dominicanus).

The osmoregulatory effects of intravenously (i.v.) administered angiotensin II (AII) at dose rates of 5, 15 and 45 ng.kg-1.min-1 were examined in kelp gulls utilizing salt gland and/or kidneys as excretory organs. In birds given i.v. infusion of 1200 mOsmolal NaCl at 0.3 ml.min-1 and utilizing only the salt glands to excrete the load, infusion of AII for 30 min consistently inhibited salt gland function in a dose-dependent manner. In birds given i.v. infusion of 500 mOsmolal NaCl at 0.72 ml.min-1 and utilizing both salt glands and kidneys to excrete the load, each dose of AII given for 2 h inhibited salt gland function but stimulated the kidney, so that the overall outputs of salt and water were enhanced and showed significant (2P less than 0.01) positive correlations with plasma AII. In birds given i.v. infusion of 200 mOsmolal glucose at 0.5 ml.min-1 and utilizing only the kidneys to excrete the load, low doses of AII (5 and 15 ng.kg-1.min-1) caused renal salt and water retention, whereas a high dose (45 ng.kg-1.min-1) stimulated salt and water output. The actions of plasma AII in kelp gulls support the concept that this hormone plays a vital role in avian osmoregulation, having effects on both salt gland and kidney function. Elevation of plasma AII consistently inhibits actively secreting salt glands, but its effects upon renal excretion depend primarily on the osmotic status as well as on the plasma AII concentration. In conditions of salt and volume loading doses of AII stimulate sodium and water excretion. With salt and volume depletion, the action of AII is bi-phasic with low doses promoting renal sodium and water retention but high circulating levels causing natriuresis and diuresis.

Glomerular filtration changes during vasotocin-induced antidiuresis in kelp gulls.

In conscious kelp gulls, intravenous infusion of arginine vasotocin (AVT) at rates of 0.03, 0.1, 0.3, and 1.0 ng.kg-1.min-1 resulted in a linear relationship between the log values of the AVT plasma concentrations (measured by radioimmunoassay) and the infusion rates, which indicated a plasma clearance rate for AVT of 15.4 ml.min-1.kg-1 when endogenous AVT formation is considered. Evaluation of the renal actions of AVT at each dose level showed that antidiuresis was consistently associated with reductions in glomerular filtration rate as well as changes in tubule water permeability. Thus the water-conserving action of plasma AVT on the kelp gull kidney involves contributions from both glomerular and tubular mechanisms over the entire physiological range found in these birds.

Plasma arginine vasotocin and angiotensin II in the water deprived Kelp gull (Larus dominicanus), Cape gannet (Sula capensis) and Jackass penguin (Spheniscus demersus).

1. The basal levels of the osmoregulatory hormones, arginine vasotocin (AVT) and angiotensin II (AII) were measured (by radioimmunoassay) in the plasma of conscious Kelp gulls, Cape gannets and Jackass penguins. 2. The responses of the hormones to similar degrees of hypertonicity and hypovolemia caused by water deprivation have also been determined. 3. Dehydration elevated plasma AVT and plasma AII in all three species. 4. The AVT concentration was increased by 2-4 fold and although in each case the correlation between plasma osmolality and plasma AVT was highly significant (2P less than 0.01), the sensitivity of release was greater in the gull (1.13 pg/ml per mOsm/kg) than in the gannet (0.36 pg/ml per mOsm/kg) or penguin (0.44 pg/ml per mOsm/kg). 5. Dehydration increased plasma AII 3-fold in the three bird types.

The association between ulcerative colitis and chronic liver disease at Tygerberg Hospital.

Twenty consecutive patients with ulcerative colitis were evaluated at the Gastro-intestinal Clinic, Tygerberg Hospital, with special reference to the biochemical tests and histological findings in the liver. Abnormal liver function tests warrant a liver biopsy, since the underlying liver disease influences the subsequent prognosis and treatment.