Patients' delay in the presentation of testis cancer in Ireland

A study of 217 cases of testis cancer in Ireland revealed a longer duration of symptoms (median 2.8 months, mean 10 months) than elsewhere: 32% of patients waited at least 6 months before seeking medical advice. Delay was associated with metastases (P = 0.001), diminished prospects of cure (P = 0.001) and increased mortality (P = 0.002) but not with marker status or complexity of treatment required. Eleven per cent did not notice a detectable swelling and 25% waited at least 3 months after such a discovery. These facts and the incidence of maldescent (12%, with more than two-thirds untreated) highlight the need for better health education in this area.

Increased oviposition and growth in immature Biomphalaria glabrata after exposure to Schistosoma mansoni

Biomphalaria glabrata snails are known to be castrated by infection with the trematode parasite Schistosoma mansoni 4-6 weeks post-infection. The pattern of oviposition in the first 35 days post-exposure (p.e.) was investigated, in snails aged 14 weeks and measuring 7-10 mm diameter which had not commenced egg-laying, by counting the numbers of eggs laid in 7-day intervals. A group of exposed snails was compared with a control non-exposed group. The exposed group included both parasitized and non-parasitized snails, and showed a significant increase in the median number of eggs laid during the periods 14-21 and 22-28 days p.e. Throughout the entire 35-day period exposed non-parasitized snails laid significantly more eggs than control snails, while parasitized snails laid significantly more eggs than controls during days 22-28 p.e. and significantly fewer during days 29-35 p.e. Parasitized snails also laid significantly more eggs/egg mass in the period 16-28 days p.e. than did control snails. Growth of the snails was measured. By day 28 p.e. the mean diameter of the exposed group was significantly greater than that of the control group. The increase in oviposition by snails soon after exposure is discussed in terms of a compensatory response for expected future suppression of egg-laying. The fact that parasitized and non-parasitized snails both show increased oviposition indicates that normal development of the parasite is not necessary to trigger the response.

Pressor effects of systemic administration of methionine and leucine enkephalin in the conscious rat

Experiments were designed using conscious Sprague-Dawley rats to determine the blood pressure (BP) and heart rate (HR) responses to intravenous doses of (1) the adrenal catecholamines noradrenaline (NA) and adrenaline (A), (2) adrenal pentapeptides methionine enkephalin (ME) and leucine enkephalin (LE), (3) combination (i.v.) injections of both ME or LE with NA or A that modulate the hemodynamic responses when the adrenal catecholamines were given alone, and (4) the possible receptor mechanisms mediating the resultant BP and HR response to i.v. pentapeptide administration. NA (0.48 and 2.4 nmol) and A (0.3 and 1.5 nmol) given i.v. evoked potent, dose-related pressor responses associated with reflex bradycardia. ME and LE (1.6 - 48 nmol) elicited transient (10-20 s) increases in mean arterial pressure (MAP), which was associated either with no change in mean heart rate (MHR), such as ME, or with slight bradycardia (i.e., LE). Combining ME or LE (16 nmol) with NA (2.4 nmol) or A (0.3 or 1.5 nmol) did not change MAP and MHR from when these respective doses of NA or A were given alone. However, 16 nmol of ME or LE with a low dose of NA (0.48 nmol) increased the pressor response compared with NA (0.48 nmol) given alone. Other experiments whereby specific receptor blockers (naloxone, diprenorphine, atropine, propranolol, phentolamine or guanethidine) were given i.v. 5 min before subsequent i.v. administration of LE or ME (16 nmol) indicated that only phentolamine or guanethidine could completely suppress the pressor responses of LE and ME. Naloxone and diprenorphine pretreatment attenuated the pressor response of LE but did not affect the BP response to ME.(ABSTRACT TRUNCATED AT 250 WORDS)

Recent trends in mortality due to testicular cancer in Ireland: a comparison with England and Wales

In the period 1961-84, the number of deaths in Ireland due to the testis cancer rose by 64%. This was due both to significant male population expansion (25.3%) and to an increased mortality rate. In the 25-34 years age group, one of the groups at highest risk, the mortality rate rose by 123%. In contrast, in England and Wales, although the male population has risen by 8.5% since 1961, the number of deaths has decreased by 17%. This is due to falling mortality rates, for example an 18% decrease in those aged 25-34 years. The highest rate of all occurred in those Irish over 75 years old. The changing Irish trends appear to lag behind those in England and Wales by some decades, and this raises important aetiological considerations.

Pressor, tachycardic and behavioral excitatory responses in conscious rats following ICV administration of ACTH and CRF are blocked by naloxone pretreatment

Experiments were conducted to compare the blood pressure and heart rate responses of conscious rats given intracerebroventricular (ICV) injections of adrenocorticotropin (ACTH 1-24) and corticotropin releasing factor (CRF). Under sodium pentobarbital anaesthesia, rats were implanted with a stainless-steel cannula into the lateral cerebral ventricle and had their right femoral artery and vein cannulated. Upon recovery (24-48 hr later) conscious, unrestrained rats were given ICV injections (total volume 5 microliter by gravity flow) of sterile saline, ACTH (1-24) (0.85 and 1.7 nmoles) or CRF (0.55 and 1.1 nmoles) and blood pressure and heart rate were monitored over the next 2 hr (from the abdominal aorta via the femoral arterial catheter). Both ACTH and CRF caused mean arterial pressure (MAP) to increase, which was paralleled with increases in mean heart rate (MHR). Moreover, these elevations in MAP and MHR were temporally associated with excessive grooming (for ACTH) and locomotor activity (for CRF), which occurred before and lasted as long as MAP and MHR were enhanced. Intravenous (IV) pretreatment whereby naloxone was given 10 min before ICV administration of ACTH (1.7 nmoles) or CRF (1.1 nmoles), showed that naloxone blocked the behavioral, pressor and tachycardic effects of both ACTH and CRF. The results demonstrate that the pressor, tachycardic and locomotor effects evoked in conscious rats by ICV administration of ACTH or CRF are antagonized by naloxone and that their hemodynamic changes may, in part, be mediated by prior behavioral activation.

The role of the pituitary-adrenal axis in the hyperthermia induced by acute peripheral or central (preoptic anterior hypothalamus) administration of morphine to unrestrained rats

The role of the pituitary-adrenal axis in the mediation of morphine-induced hyperthermia of conscious, unrestrained rats was investigated. Rectal (TR) and tail (Tt) temperatures and oxygen uptake rates (VO2) were measured following peripheral or central injection of morphine sulphate (MS) in groups of Sprague-Dawley rats before and after adrenalectomy (adx), hypophysectomy (hyp), or pituitary suppression (via dexamethasone treatment). The hyperthermic TR responses of groups given MS either subcutaneously (5 or 15 mg/kg) or directly into the preoptic anterior hypothalamus (POAH, 1 or 10 micrograms/microL) before adx were not different upon retesting with the same dose of MS 2 weeks later following adx. The hyperthermia with MS was not caused by vasoconstriction or by increases in basal metabolic rate, for Tt rose after the opiate injections whereas oxygen uptake rates (VO2) were reduced. Unexpectedly, the TR following POAH injections of sterile saline (SS) or deionized water after adx increased from those seen before adx. Adx groups supplemented with dexamethasone phosphate (either chronically with 20 micrograms/kg daily for 2 weeks post-adx before retesting with MS or acutely with 250 micrograms/kg 2 h before retesting) showed a hyperthermia to MS (5 mg/kg sc or 1.0 microgram/microL POAH) similar to that seen before adx. However, dexamethasone phosphate (250 micrograms/kg) supplementation to adx rats, that received POAH injections of SS, did reduce the rise in TR. Hyp rats given MS (5 mg/kg, sc) also evoked hyperthermic responses similar to those of non-hyp control groups. The results clearly show that the acute hyperthermia of unrestrained rats induced by either peripheral or central injections of morphine is not caused by activation of the pituitary-adrenal axis.

Blood pressure responses of conscious rats to intravenous administration of enkephalin derivatives (D-ala2 methionine and leucine enkephalinamide, and methionine and leucine enkephalinamide

The present study was designed to determine the blood pressure (BP) responses of conscious rats given intravenous (IV) injections of enkephalin derivatives (D-ala2-methionine enkephalinamide, DAMEA; D-ala2-leucine enkephalinamide, DALEA; methionine enkephalinamide, MEA; leucine enkephalinamide, LEA) and the receptor mechanisms mediating the resultant change in BP. IV injection of 1.6-16.0 nmoles of DAMEA or DALEA caused a transient but potent decrease in mean arterial pressure (MAP) and mean heart rate (MHR). LEA and MEA (16.0 nmoles) given IV produced slight pressor responses, which were not associated with concomitant tachycardia whereas 48 nmoles of MEA elicited a hypotensive effect accompanied by a fall in MHR. Pretreatment studies whereby various receptor antagonists (naloxone, diprenorphine, phentolamine, D-L-propranolol or atropine) were given IV 5 min before subsequent IV administration of DAMEA, DALEA, MEA or LEA (16 nmoles) showed that naloxone, diprenorphine and atropine blocked the depressor and bradycardic effects of DALEA and DAMEA. Naloxone and phentolamine suppressed the pressor response of both MEA and LEA (16.0 nmoles) while diprenorphine blocked the rise in MAP to only MEA. The results show that DAMEA and DALEA mediate their depressor actions in conscious rats via a negative chronotropic effect through an interaction of muscarinic cholinergic receptors on the myocardium. It suggested that the pressor response of MEA and LEA may be produced via an alpha-receptor mediated effect on the peripheral vasculature to cause vasoconstriction.

Thermoregulatory responses of dystrophic hamsters to changes in ambient temperatures

The ability of dystrophic hamsters to maintain their body temperature despite abnormal muscle and brown adipose tissue, two organs involved in thermoregulation, was evaluated. Dystrophic hamsters (CHF 146) between the ages of 30 and 160 days kept at 21 degrees C had core (rectal) temperatures (TR) that were 0.5-1.5 degrees C lower than Golden Syrian controls. The reduced core temperatures of dystrophic hamsters were unlikely the result of an incapacity to generate heat since the dystrophic hamsters were able to maintain their TRs during 3 h of acute cold stress (4 degrees C) and to adapt to prolonged cold exposure. However, TRs of cold-acclimated dystrophic hamsters were still 1 degree C below TRs of cold-acclimated control animals. By contrast, increasing the ambient temperature raised TRs of both normal and dystrophic hamsters. When kept at 32 degrees C overnight, the TRs of dystrophic hamsters remained significantly below those of control animals. When heat-exposed dystrophic hamsters were returned to 21 degrees C, their TRs returned to values significantly lower than those of control hamsters. Thus, dystrophic hamsters showed a capacity to thermoregulate, like control hamsters, but appeared to do so at a lower temperature. The reduced core temperatures of dystrophic hamsters kept at 21 degrees C cannot be explained by a reduction in metabolic activity since newborns and 30- and 140-day-old dystrophic hamsters had rates of oxygen consumption (VO2) and carbon dioxide production (VCO2) that were similar to those of controls. These results suggest that the thermoregulatory set point may be altered in dystrophic hamsters.

No inotropic action of enkephalins or enkephalin derivatives on electrically-stimulated atria isolated from lean and obese rats

Inotropic actions of the endogenous enkephalins, leucine enkephalin [( Leu] enkephalin) and methionine enkephalin [( Met] enkephalin), and derivatives, [D-Ala2-methionine] enkephalinamide (DAMEA) and [D Ala2-leucine]enkephalinamide (DALEA) were tested, alone or in combination with noradrenaline (NA), (+/-)-isoprenaline or carbachol, on electrically-stimulated atria excised from Sprague-Dawley, fatty, Zucker (fa/fa) and lean, hooded heterozygous (Fa/fa) rats. [Met] enkephalin, [Leu] enkephalin, DAMEA and DALEA (4 X 10(-7)M to 4 X 10(-4)M) caused no significant changes in atrial tension in any group compared to pre-injection control values or those following the infusion of Krebs-Henseleit control solution. NA and isoprenaline (10(-7) to 10(-6)M) caused significant, dose-related increases in atrial tension in each of the three strains of rats tested with the Fa/fa group showing the greatest change and fastest rate of tension development. [Met] enkephalin, [Leu] enkephalin, DAMEA or DALEA (4 X 10(-6)M) infused concurrently with NA or isoprenaline (10(-6)M) evoked atrial tension changes within each group that were not different from those observed when NA or isoprenaline was administered alone. Carbachol (10(-9) and 10(-8)M) caused a dose-related decrease (10% and 30-40%, respectively, from pre-injection control values) in atrial tension in auricles excised from all three groups. Again, infusion of [Met] enkephalin, [Leu] enkephalin, DAMEA or DALEA (4 X 10(-6)M) together with carbachol (10(-8)M) did not affect atrial tension changes of auricles isolated from any group compared to when carbachol was given alone. The results indicate that the endogenous pentapeptides, [( Met] or [Leu] enkephalin), or derivatives (DAMEA and DALEA) do not affect atrial tension of electrically-stimulated auricles isolated from Sprague-Dawley, fa/fa or Fa/fa rats. In addition, these pentapeptides do not modify the positive inotropic actions of NA or isoprenaline or the negative inotropic effects of carbachol. It is suggested that in vivo, the enkephalins or enkephalin derivatives do not have a direct action on the heart to alter myocardial contractility.

Is acute morphine hyperthermia of unrestrained rats due to selective activation of brown adipose tissue thermogenesis?

Experiments were conducted to determine if the hyperthermia after acute morphine sulfate (MS) administration was due to selective activation of brown adipose tissue (BAT) thermogenesis. Interscapular BAT temperature (TIBAT) and core (rectal) temperature (TR) were measured concurrently in groups of unrestrained, male Sprague-Dawley rats kept at 21.0 degrees C before and after i.p. (0.75, 2.0 or 10.0 mg/kg) or intracerebroventricular injections (200 ng- greater than 5 ul) of MS or sterile saline. TRS and TIBATS increased 0.6-1.0 degree C after i.p. intracerebroventricular injections of MS but the time course and magnitude of the changes in TIBATS from mean preinjections readings were not different from the increases in TRS. By contrast, isoproterenol HCl (0.5 mg/kg i.p.), known to activate BAT heat production, given to rats kept at 4 or 21 degrees C raised the TIBATS significantly above changes seen in TRS. Rats given MS in which the capacity for brown fat heat production had been increased previously (cold adaptation) or decreased (fasting or bilateral denervation) again evoked increases in TIBAT and TRS that were not significantly different from one another or from the response of warm-adapted, normophagic controls. Furthermore, oxygen uptakes were reduced after MS compared to oxygen uptakes after saline injections. [3H]Guanosine diphosphate binding to interscapular BAT mitochondria isolated from rats sacrificed at peak morphine hyperthermia (greater than 1.0 degree C) was not different from that of saline control animals. The results indicate clearly that the hyperthermia occurring in unrestrained rats after acute central or peripheral opiate administration is not due to selective activation of BAT thermogenesis.

Thermoregulatory (core, surface and metabolic) responses of unrestrained rats to repeated POAH injections of beta-endorphin or adrenocorticotropin

Repeated preoptic-anterior hypothalamic (POAH) injections of saline and 10 or 25 micrograms/microliters of beta-endorphin or ACTH were given to groups of male Sprague-Dawley rats. One hr after the fifth injection of beta-endorphin or ACTH, each rat received a POAH injection of naloxone HCl (10 micrograms/microliters). Core (Tre-rectal) and surface (Tt-tail) temperatures, metabolic (VO2) and behavioral responses were recorded 30 min before and 60 min after each drug injection. The initial POAH injection of either dose of beta-endorphin produced a hyperthermia. Peak hyperthermia was reduced in the group given 10 micrograms/microliters of beta-endorphin repeatedly. TtS rose after each beta-endorphin injection but temporally lagged Tre increases. Metabolic rate (VO2) was increased with repeated POAH injections of beta-endorphin. Naloxone reduced the elevated Tre seen with beta-endorphin by increasing Tt's further and reducing VO2. POAH administration of ACTH evoked only a slight hyperthermic Tre response, but elevated TtS and VO2S, due to enhanced grooming and explorative behavior. With repeated ACTH injections, TreS did not change from those on the first day as TtS and VO2 remained enhanced. Naloxone reduced VO2 and TtS of the ACTH-treated rats but TreS still were unchanged. Results suggest that the hyperthermia of unrestrained rats given an acute as opposed to repeated POAH beta-endorphin injections is mediated by different effector mechanisms. With the doses used, the slight and unchanging TreS seen with ACTH occurred because this peptide increased heat production due to locomotor activation yet also exaggerated heat loss by vasodilating the peripheral vasculature.

Assessment of biomaterials as components of a reciprocating dialyser during canine dialysis

A recently reported device, the sorbent suspension reciprocating dialyser (SSRD), was investigated for use as a test system for biocompatibility of dialyser components. The device is easy to assemble and operate, and allows minimal blood contact with foreign material outside of dialyser components. Its constant pressure/variable flow rate operation allows quantification of degree of clotting of dialyser versus time. The effect of heparinization of the blood distribution gaskets (BDG) of the device on performance and dialyser lifetime was investigated. Heparin was bound to the surface of polyethylene gaskets by immersion in a solution of tridodecylmethylammonium chloride (TDMAC)--heparin complex for several hours. Gaskets were then assembled in an SSRD which was then used for experimental dialysis in dogs with AV shunts. Dialysers assembled using non-heparinized gaskets were used as controls. Blood coagulation tendency was quantified by the activated clotting time (ACT) and partial thromboplastin time (PTT), and these values correlated with the rate of clotting of the device. Heparinization of the gaskets resulted in the prevention of clotting in the dialyser until the final minutes of dialysis in all cases, in contrast to the constant decay of blood fill volume and evidence of clotting in the non-heparinized cases. However, dialyser lifetime was not significantly increased by gasket heparinization. At normal initial values of ACT (80-95 s) dialyser clotting occurred in 10-15 min. In tests with non-heparinized gaskets and systemically heparinized dogs, values obtained in the ACT test were observed to decrease during dialysis, indicating the disappearance of heparin from the blood. Both ACT and PTT tests show promise as predictors of dialyser lifetime.

Support of an anephric dog for 54 days with ambulatory peritoneal dialysis and a newly designed peritoneal catheter

A bilaterally nephrectomized dog was successfully supported with peritoneal dialysis for 54 days, using a radically new design of access catheter and a human dialysis schedule designated as continuous ambulatory peritoneal dialysis. The dog remained active and alert with a stabilized blood urea nitrogen of 30 to 40 mg/dl and a serum creatinine concentration of 4 to 6.5 mg/dl. Problems encountered with the peritoneal dialysis included the propensity for developing peritonitis, anorexia, and a significant plasma protein loss in the dialysate fluid as result of leakage across the peritoneum. Protein loss coupled with anorexia produced a catabolic state, and the animal was euthanatized because of this, at postnephrectomy day 54. The development of a new catheter design alleviated the drainage problems of the straight tube Tenckhoff catheter. Its use coupled with the continuous ambulatory peritoneal dialysis schedule and detailed management techniques allowed using the anephric dog as a model of uremia. In addition, peritoneal dialysis could be a viable treatment for animals presenting with acute reversible anuric or oliguric renal failure where conservative medical management with fluids and diuretics has failed to give clinical improvement.

Doppler ultrasonic detection of particulate release during hemodialysis with cellulose hollow-fiber and sorbent suspension reciprocating dialyzers

Doppler ultrasound is a noninvasive technique for monitoring moving objects such as flowing blood while ignoring stationary objects such as shunt tubing. A Doppler system was investigated to determine its sensitivity in detecting particulate release in blood during hemodialysis. Seven hemodialysis procedures with dogs and six trials with humans were done using a sorbent suspension reciprocating dialyzer ( SSRD ). Two additional trials were done with humans using a cellulose acetate hollow-fiber dialyzer (HFD). A large increase (approximately twofold) was found in the reflected Doppler signal in outflowing blood from the SSRD and HFD in both dogs and humans. Numerous additional studies to characterize the nature of the particulate matter showed platelet aggregates in the dogs and fibrinogen-fibrin degradation products in the humans to be present in the outflowing blood. In vitro studies suggested microscopic air bubbles (less than 25 micron in diameter) may have contributed to the particulate matter detected during hemodialysis by this sensitive monitoring system.

Ventromedial and lateral hypothalamic injections of naloxone or naltrexone suppress the acute food intake of food-deprived rats

Experiments were conducted to determine the anorexigenic effects of ventromedial (VMH) and lateral hypothalamic (LH) injections of the mu-opiate receptor antagonists, naloxone and naltrexone, on food-deprived (20 h) rats. Lever pressing to obtain food pellets was measured in groups of hungry, male Sprague-Dawley rats following VMH, LH or subcutaneous (SC) injections of saline, naloxone or naltrexone. VMH injections of either narcotic antagonist (5 and 10 micrograms/microliter) and LH injections of naloxone (5 and 10 micrograms/microliter) decreased the total 90-min food intake, compared to saline controls, due to suppressed feeding especially during the initial 30-min interval. Rats given SC injections of naloxone (10 mg/kg) also decreased their food intake compared to amounts eaten after SC saline was given. Decrements in food consumption relative to saline controls were similar following VMH or LH administration of naloxone. Moreover, the anorexia observed following VMH naloxone administration was similar to that found after VMH injections of equal doses of naltrexone.

Opiate modulation of thermoregulation in adult Pekin ducks

Lightly restrained, adult Pekin ducks (2-3 kg) were given a subcutaneous (sc) injection of either sterile saline or morphine sulphate (10 or 30 mg/kg), followed 90 min later by a sc injection of naloxone hydrochloride (10 mg/kg). Core (cloacal TC) and surface (web TW) temperatures were continuously monitored along with heart (fH) and respiratory rates (fresp). In a related study, another group of Pekin ducks was placed in an open respirometer chamber so that oxygen consumption (VO2) could be determined following administration of sterile saline or morphine. Morphine sulphate (10 and 30 mg/kg) caused a hyperthermic core temperature response which persisted over the 90-min test period. This hyperthermia was due to an initial but transient vasoconstriction of the peripheral vasculature, as inferred from the sudden drop in foot web temperature. It was also found that morphine rapidly enhanced VO2 of the ducks, which remained elevated throughout the entire 90-min postmorphine injection period. TWS began to increase as peak TCS were reached (congruent to 30 min postinjection), and were above control levels until the end of the morphine period. fH was elevated following morphine administration but fresp was not altered. Upon naloxone administration, TCS were reduced because heat production was decreased (VO2 fell) and heat dissipation was enhanced further by increased vasodilatation (elevated TW) and a substantial (greater than 10-fold) increase of fresp (gular fluttering). Results demonstrate that morphine caused hyperthermic TC changes in adult Pekin ducks by increasing heat production while, at the same time, minimizing heat loss by vasoconstricting the peripheral vasculature and inhibiting respiration.

Acute stimulation of feeding with repeated injections of morphine sulphate to non-obese and fatty Zucker rats

Food intake studies with genetically obese rodents show that these hyperphagic animals, which have increased central and peripheral levels of endogenous opioid peptides (E.O.P.), have an increased sensitivity to the suppressive feeding effects of narcotic antagonists compared to lean controls. Feeding experiments were conducted to determine if genetically obese rats, with enhanced E.O.P., have a reduced sensitivity toward the narcotic agonist property of stimulated feeding seen in non-obese rats. Food intake was monitored continuously over each experimental day in groups of female Sprague-Dawley (S.D.,), fatty Zucker (fa/fa) and their lean heterozygote littermates (Fa/fa) following subcutaneous a.m. injections of sterile saline, morphine sulphate (5 or 10 mg/kg) or naloxone HCl (10 mg/kg) and during recovery. Acute 4-h post-injection feeding was reduced in all groups with the first 10 mg/kg injection of morphine sulphate. With repeated morphine administration, a phase of stimulated feeding occurred in both obese and non-obese groups. Due to the post-injection phase of vigorous feeding with repeated morphine injections, the circadian pattern of day/night food intake of all groups was altered such that daytime feeding increased from saline control levels. Naloxone HCl abolished the post-injection phase of stimulated feeding seen with chronic morphine injections and reduced 4-h post-injection food intakes. Plasma glucose and serum insulin levels were decreased in non-obese rats from saline controls of blood samples taken 2-h following the 7th daily M.S. injection. These levels increased again by the end of the recovery period. No blood glucose or insulin changes were seen in the obese Zucker rats with morphine administration.(ABSTRACT TRUNCATED AT 250 WORDS)