Isolation and characterization of full and truncated forms of human breast carcinoma protein BA46 from human milk fat globule membranes

We have isolated and characterized two proteins of 50 and 30 kDa from human milk fat globule membranes of healthy donors. N-terminal and internal sequencing revealed that the 50-kDa protein is the full-length human breast carcinoma protein BA46 that is highly expressed in human breast tumors. The 30-kDa protein is a truncated form of protein BA46 which consists of the C-terminal factor V/VIII-like domain of BA46 and which appears to anchor BA46 to the milk fat globule membrane. Defective release of the epidermal growth factor domain containing a surface RGD motif may be related to involvement of BA46 in breast cancer.

Evaluation of markers of bone and collagen turnover in patients with active and preclinical Cushing's syndrome and in patients with adrenal incidentaloma

Although steroid-induced negative effects on bone and collagen have been well described in corticosteroid-treated patients, few studies have extensively evaluated bone and collagen turnover in patients with endogenous Cushing's syndrome. In this work serum bone-Gla protein (BGP), C-terminal cross-linked telopeptide of type I collagen (ICTP) and N-terminal propeptide of type III procollagen (PIIINP) levels were determined in patients with active (n = 12) and preclinical (n = 6) Cushing's syndrome, adrenal incidentalomas (n = 35) and in healthy controls (n = 28). In patients with overt Cushing's syndrome, serum BGP (0.9+/-0.2 ng/ml), ICTP (2.7+/-0.2 ng/ml) and PIIINP (1.9+/-0.2 ng/ml) levels were significantly lower (P < 0.0001) than in controls (5.5+/-0.2, 3.9+/-0.2 and 3.2+/-0.2 ng/ml respectively). In preclinical Cushing's syndrome, serum BGP (2.5+/-0.8 ng/ml), ICTP (2.2+/-0.1 ng/ml) and PIIINP (2.2+/-0.2 ng/ml) levels were significantly lower than in normal subjects (P < 0.0001, P < 0.0001 and P < 0.02 respectively), being similar to those recorded in overt Cushing's syndrome. In patients with adrenal incidentaloma, serum BGP (4.2+/-0.5 ng/ml) and ICTP (2.9+/-0.2 ng/ml) levels were significantly lower than those found in controls (P < 0.05 and P < 0.001 respectively), while serum PIIINP levels (3.6+/-0.2 ng/ml) did not differ from those of normals. In particular, 9/35 patients with adrenal incidentaloma had markedly depressed BGP levels (<2.0 ng/ml; mean 0.8+/-0.1 ng/ml): all patients of this subgroup showed an exaggerated 17-hydroxyprogesterone increase after ACTH administration. In the same patients, serum ICTP (3.0+/-0.4 ng/ml) and PIIINP (3.6+/-0.2 ng/ml) levels did not differ from those found in the incidentaloma group. In conclusion, our study indicates that bone and collagen turnover are markedly affected in patients with overt and preclinical Cushing's syndrome. Although patients with adrenal incidentaloma do not show any signs or symptoms of overt hypercortisolism, the presence of reduced BGP and ICTP levels might be considered a further index of an 'abnormal' pattern of steroid secretion in some of them. As a consequence, the presence of early alterations in markers of bone turnover might be useful for selecting those patients who need more accurate follow-up of the adrenal mass.

Prenatal diagnosis of 22q11 microdeletion in a fetus with a conotruncal heart defect

A case of prenatal diagnosis of 22q11 microdeletion in a fetus with a conotruncal heart defect is described. This type of chromosomal aberration has been shown to be present in up to 30% of isolated conotruncal anomalies and in most cases of DiGeorge and velocardiofacial syndromes. The implications of such a diagnosis on prenatal counselling are discussed.

The effect of in vitro modeling conditions on the surface reactions of bioactive glass

Using one parametric variation in solution composition, this paper documents that the surface reactions on bioactive glass (BG) 45S5 are exquisitely dependent upon the modeling conditions. The solutions used were 0.05 M tris hydroxymethyl aminomethane/HCl (tris buffer), tris buffer complemented with plasma electrolyte and/or serum, and serum. The reacted surfaces were analyzed using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDXA), and Rutherford backscattering spectroscopy (RBS). Post-immersion solutions were analyzed for changes in Ca and PO4 concentrations. After a short immersion (3 h), a crystalline, carbonated hydroxyapatite (c-HA) layer formed only in tris. Reaction surfaces of different structure, morphology, and composition were observed after various short and longer term immersions in all other solutions. They comprised two layers with the layer in contact with the bulk consisting mainly of Si; the outer layer, composed of Si, Ca, and P, was amorphous, and had a Ca/P ratio of about 1. Serum proteins adsorbed on the BG surfaces at the early stages of the solution-mediated BG reactions. Formation of a crystalline c-HA layer was delayed up to three or more days in solution with plasma ions. In the presence of serum, only amorphous surfaces composed of Si, Ca, and P were observed for any time up to seven days of immersion. The present data suggest that serum proteins adsorb in tandem with the occurrence of solution-mediated reactions leading to formation of a silica-gel. Amorphous Ca-P phases accumulate in the Si-rich matrix. Furthermore, the present data, in conjunction with the data published before, suggest that physicochemical and cell-mediated reactions occur in parallel to form the glass-tissue interfacial layer.

Requirement for the ryanodine receptor type 3 for efficient contraction in neonatal skeletal muscles

The skeletal isoform of Ca2+ release channel, RyR1, plays a central role in activation of skeletal muscle contraction. Another isoform, RyR3, has been observed recently in some mammalian skeletal muscles, but whether it participates in regulating skeletal muscle contraction is not known. The expression of RyR3 in skeletal muscles was studied in mice from late fetal stages to adult life. RyR3 was found to be expressed widely in murine skeletal muscles during the post-natal phase of muscle development, but was not detectable in muscles of adult mice, with the exception of the diaphragm and soleus muscles. RyR3 knockout mice were generated, and it was shown that skeletal muscle contraction in these mice was impaired during the first weeks after birth. In skeletal muscles isolated from newborn RyR3(-/- )mice, but not in those from adult mice, the twitch elicited by electrical stimulation and the contracture induced by caffeine were strongly depressed. These results provide the first evidence that RyR3 has a physiological role in excitation-contraction coupling of neonatal skeletal muscles. The disproportion between the low amount of RyR3 and the large impact of the RyR3 knockout suggests that this isoform contributes to the amplification of Ca2+ released by the existing population of ryanodine receptors (RyR1).

The unusual amino acid triplet Asn-Ile-Cys is a glycosylation consensus site in human alpha-lactalbumin

Human alpha-lactalbumin has not been described as a glycoprotein, despite the fact that several alpha-lactalbumins of both ruminant and nonruminant species are known to be glycosylated. In all these species the glycosylation site is the 45Asn in the usual triplet 45Asn-Gly/Gln-47Ser. We have found that human alpha-lactalbumin is glycosylated and the glycosylation site has been determined by protein sequencing and mass spectrometry. We report an unusual glycosylation site at 71Asn in the triplet 71Asn-Ile-73Cys, which is conserved in all known alpha-lactalbumins except red-necked wallaby. That a relatively small proportion of the protein is glycosylated (about 1%) may reflect the importance of this region of the protein sequence to the molten globule state of alpha-lactalbumin.

The glutamate receptor/NO/cyclic GMP pathway in the hippocampus of freely moving rats: modulation by cyclothiazide, interaction with GABA and the behavioural consequences

Monitoring of extracellular cGMP during intracerebral microdialysis in freely moving rats permits the study of the functional changes occurring in the glutamate receptor/nitric oxide (NO) synthase/guanylyl cyclase pathway and the relationship of these changes to animal behaviour. When infused into the rat hippocampus in Mg2+-free medium, cyclothiazide, a blocker of desensitization of the AMPA-preferring receptor, increased cGMP levels. The effect of cyclothiazide (300 microM) was abolished by the NO synthase inhibitor L-NARG (100 microM) or the soluble guanylyl cyclase inhibitor ODQ (100 microM). During cyclothiazide infusion the animals displayed a pre-convulsive behaviour characterized by frequent "wet dog shakes" (WDS). Neither L-NARG nor ODQ decreased the WDS episodes. Both cGMP and WDS responses elicited by cyclothiazide were prevented by blocking NMDA receptor function with the glutamate site antagonist CGS 19755 (100 microM), the channel antagonist MK-801 (30 microM) or Mg2+ ions (1 mM). The AMPA/kainate receptor antagonists DNQX (100 microM) and NBQX (100 microM) abolished the WDS episodes but could not inhibit the cyclothiazide-evoked cGMP response. DNQX or NBQX (but not MK-801) elevated, on their own, extracellular cGMP levels. The cGMP response elicited by the antagonists appears to be due to prevention of a glutamate-dependent inhibitory GABAergic tone, since infusion of bicuculline (50 microM) caused a strong cGMP response. The results suggest that (a) AMPA/kainate receptors linked to the NO/cGMP pathway in the hippocampus (but not NMDA receptors) are tonically activated and kept in a desensitized state by endogenous glutamate; (b) blockade of AMPA/kainate receptor desensitization by cyclothiazide leads to endogenous activation of NMDA receptors; (c) the hippocampal NO/cGMP system is under a GABAergic inhibitory tone driven by non-NMDA ionotropic receptors; (d) the pre-convulsive episodes observed depend on hippocampal NMDA receptor activation but not on NO and cGMP production.

Expression of the ryanodine receptor type 3 calcium release channel during development and differentiation of mammalian skeletal muscle cells

In vertebrate skeletal muscles, the type 1 isoform of ryanodine receptor (RyR1) is essential in triggering contraction by releasing Ca2+ from the sarcoplasmic reticulum in response to plasma membrane depolarisation. Recently, the presence of another RyR isoform, RyR3, has been detected in mammalian skeletal muscle cells, raising the question of the eventual relevance of RyR3 for muscle cell physiology. The expression of RyR3 was investigated during differentiation of skeletal muscle cells. Using antibodies able to distinguish the different RyR isoforms and Western blot analysis, the RyR3 protein was detected in the microsomal fractions of differentiated skeletal muscle cells but not of undifferentiated cells. Accordingly, blocking muscle differentiation by the addition of either transforming growth factor-beta or basic fibroblast growth factor prevented the expression of the RyR3 protein. In differentiated skeletal muscle cells, RyR3 was expressed independent of cell fusion and myotube formation. The expression of RyR3 was also investigated during development of the diaphragm muscle. The RyR3 content in the diaphragm muscle increased between the late stage of fetal development and the first postnatal days. However, at variance with RyR1, which reached maximum levels of expression 2-3 weeks after birth, the expression of RyR3 was found to be higher in the neonatal phase of the diaphragm muscle development (2-15 days after birth) than in the same muscle from adult mice. The differential content of RyR3 in adult skeletal muscles was found not to be mediated by neurotrophic factors or electrical activity. These findings indicate that RyR3 is preferentially expressed in differentiated skeletal muscle cells. In addition, during skeletal muscle development, its expression is regulated differently from that of RyR1.

Detection of specific IgE to human milk proteins in sera of atopic infants

Specific IgE (sIgE) for cow's milk proteins (CMP) have been reported to be present in blood sera of exclusively breast-fed infants. The aim of this study was to find whether the presence of sIgE to human milk proteins in the sera of exclusively breast-fed infants could explain the apparent detection of sIgE to CMP in infants that were never previously in contact with cow's milk. sIgE for human milk whey proteins were found in the blood sera of atopic infants, and these sIgE strongly cross-reacted with the corresponding CMP. In none of the sera examined were sIgE to bovine beta-lactoglobulin detected.

A randomized study of chemotherapy with cisplatin plus etoposide versus chemoendocrine therapy with cisplatin, etoposide and the pineal hormone melatonin as a first-line treatment of advanced non-small cell lung cancer patients in a poor clinical state

Recent studies suggest that the pineal hormone melatonin may reduce chemotherapy-induced immune and bone marrow damage. In addition, melatonin may exert potential oncostatic effects either by stimulating host anticancer immune defenses or by inhibiting tumor growth factor production. On this basis, we have performed a randomized study of chemotherapy alone vs. chemotherapy plus melatonin in advanced non-small cell lung cancer patients (NSCLC) with poor clinical status. The study included 70 consecutive advanced NSCLC patients who were randomized to receive chemotherapy alone with cisplatin (20 mg/m2/day i.v. for 3 days) and etoposide (100 mg/m2/day i.v. for 3 days) or chemotherapy plus melatonin (20 mg/day orally in the evening). Cycles were repeated at 21-day intervals. Clinical response and toxicity were evaluated according to World Health Organization criteria. A complete response (CR) was achieved in 1/34 patients concomitantly treated with melatonin and in none of the patients receiving chemotherapy alone. Partial response (PR) occurred in 10/34 and in 6/36 patients treated with or without melatonin, respectively. Thus, the tumor response rate was higher in patients receiving melatonin (11/34 vs. 6/35), without, however, statistically significant differences. The percent of 1-year survival was significantly higher in patients treated with melatonin plus chemotherapy than in those who received chemotherapy alone (15/34 vs. 7/36, P < 0.05). Finally, chemotherapy was well tolerated in patients receiving melatonin, and in particular the frequency of myelosuppression, neuropathy, and cachexia was significantly lower in the melatonin group. This study shows that the concomitant administration of melatonin may improve the efficacy of chemotherapy, mainly in terms of survival time, and reduce chemotherapeutic toxicity in advanced NSCLC, at least in patients in poor clinical condition.

Measurement of catecholamines in mouse bone marrow by means of HPLC with electrochemical detection

BACKGROUND AND OBJECTIVE

Noradrenergic innervation is present in the bone marrow and adrenergic agents can modulate hematopoiesis. However, since no data are available concerning endogenous catecholamines at this level, we investigated their presence and origin.

METHODS

Using a high performance liquid chromatographic method, we have and measured endogenous catecholamines in bone marrow from normal, 6-OHDA-treated and pargyline-treated mice.

RESULTS

Noradrenaline, adrenaline and dopamine levels were, respectively, 2806.74 +/- 408.85, 803.37 +/- 87.66 and 274.47 +/- 51.54 pg/g of tissue. Noradrenaline levels were lower after 6-OHDA (1130.47 +/- 142.73 pg/g of tissue, p < 0.01 vs. control values) and higher after pargyline (4122.62 +/- 509.54 pg/g of tissue, p < 0.05). None of these treatments significantly affected adrenaline or dopamine content.

INTERPRETATION AND CONCLUSIONS

Noradrenaline in the bone marrow originates mainly from sympathetic nerve endings and is metabolized through specific enzymatic pathways. Adrenaline and dopamine may originate from other sources, such as the systemic circulation.

Body composition analysis by dual energy x-ray absorptiometry and anthropometry in adults with childhood-onset growth hormone (GH) deficiency before and after six months of recombinant GH therapy

Measurements of total body fat (BF) and fat free mass (FFM) obtained by anthropometry, using the Durnin and Womersley (DW) equations, and by total body dual energy x-ray absorptiometry (DXA) were compared in 8 adults with childhood-onset GH deficiency (GHD) and in 9 healthy subjects. The sensitivity of these two methods in detecting the changes in body composition produced by six months of GH therapy in patients with GHD was also compared. Anthropometric determination of percent BF was calculated from the sum of biceps, triceps, subscapular and suprailiac skinfolds, using the appropriate DW and Siri equations for body density and percent fat estimation. FFM was calculated by subtracting BF from body mass (BM). BF and FFM were also determined by DXA (QDR 1000/W, Hologic Inc). The data obtained from the GHD patients were compared with those recorded in a control group of healthy males, matched for sex, age and physical activity. Body composition obtained by anthropometry: before GH treatment, significant differences existed between patients and controls in terms of BM (mean +/- SD: 45.8 +/- 10.0 vs 71.7 +/- 6.6 kg), percent BF (21.0 +/- 3.2 vs 17.1 +/- 3.7%) and FFM (36.0 +/- 6.5 vs 59.3 +/- 3.7 kg), while body mass index (BMI, kg/m2) values were similar in the two groups. Six months of GH therapy did not change BM and BMI, but caused a significant reduction of percent BF (from 21.0 +/- 3.2 to 18.6 +/- 4.0%) and a rise of FFM (from 36.0 +/- 6.5 to 38.0 +/- 6.7 kg). After treatment, no significant differences were found between percent BF values of patients and controls. Body composition obtained by DXA: BF (22.0 +/- 3.9%) and FFM (37.2 +/- 8.0 kg) of patients significantly differed from those of controls (16.8 +/- 3.7% and 59.8 +/- 3.7 kg) before treatment; after GH treatment, percent BF values (17.7 +/- 4.9%) of patients were similar to those of controls. Anthropometry vs DXA: high correlation (p < 0.001-0.0001, R2 = 0.784-0.988) was found between the percent BF and FFM determined by anthropometry and by DXA for both patients, before and after treatment, and controls. It is noteworthy that, for both BF and FFM, most values were evenly distributed along the identity line, showing no systematic overestimation or underestimation by anthropometry. The relation between DXA and anthropometry was maintained even after GH treatment. These results indicate that body fat and FFM assessment by anthropometry are comparable to those by DXA. GH-induced changes in body composition in hypopituitary adults are detected with the same level of accuracy by the two techniques. The reliability, practicality and low cost of anthropometry favour its use for the assessment of body composition even in GHD patients.

Adults with childhood-onset growth hormone deficiency: effects of growth hormone treatment on cardiac structure

OBJECTIVES

To evaluate the effects of growth hormone deficiency (GHD) and of growth hormone (GH) therapy on cardiac structure in adults with childhood-onset GHD.

SETTING

Out-patient clinic in the Italian Institute for Auxology, Milan.

SUBJECTS

Eight adults with childhood-onset GHD and eight healthy controls, matched for sex, age, exercise and body mass index.

INTERVENTIONS

Recombinant GH (Saizen Serono, Italy), administered in a conventional dose of 0.5 IU kg-1 week-1 for 6 months.

MAIN OUTCOME MEASURES

Cardiac structure parameters, evaluated by two-dimensional, M-mode and Doppler echocardiograms, and stress test, by means of a modified Bruce protocol with a bicycle ergometer, were determined before and after 6 months GH therapy.

RESULTS

Before treatment, mean (+/- SE) intraventricular septal thickness (IVST: 7.1 +/- 0.2 mm), LV posterior wall thickness (LVPT: 5.2 +/- 0.1 mm), LV mass (LVM: 94.6 +/- 5.0 g), LV mass index (LVM/body surface area, LVMI: 65.1 +/- 3.0 g m-2) and left ventricular end-diastolic diameter (LVED: 41.4 +/- 0.6 mm) of patients were significantly lower (P < 0.01) than in controls, whilst LV end-systolic diameter (LVES) of patients (25.5 +/- 0.7 mm) was similar to controls (27.5 +/- 0.7). GH treatment significantly (P < 0.01) increased LVPT (6.8 +/- 0.2 mm), LVM (111.6 +/- 4.6 g) and LVMI (80.5 +/- 3.5 g m-2); no significant changes were observed in LVED, LVES and IVST values. The stress test showed a significant improvement of cardiac performance, as demonstrated by the reduction of blood pressure x heart rate product at the same workload (basal: 32,722.5 +/- 897.4 vs. after: 25,574.6 +/- 439.7).

CONCLUSIONS

GH plays a role in the maintenance of a normal cardiac structure in adulthood. The present study suggests that GH treatment might be able to improve the cardiac structure of patients with childhood-onset GHD.

Treatment of cancer chemotherapy-induced toxicity with the pineal hormone melatonin

Experimental data have suggested that the pineal hormone melatonin (MLT) may counteract chemotherapy-induced myelosuppression and immunosuppression. In addition, MLT has been shown to inhibit the production of free radicals, which play a part in mediating the toxicity of chemotherapy. A study was therefore performed in an attempt to evaluate the influence of MLT on chemotherapy toxicity. The study involved 80 patients with metastatic solid tumors who were in poor clinical condition (lung cancer: 35; breast cancer: 31; gastrointestinal tract tumors: 14). Lung cancer patients were treated with cisplatin and etoposide, breast cancer patients with mitoxantrone, and gastrointestinal tract tumor patients with 5-fluorouracil plus folates. Patients were randomised to receive chemotherapy alone or chemotherapy plus MLT (20 mg/day p.o. in the evening). Thrombocytopenia was significantly less frequent in patients concomitantly treated with MLT. Malaise and asthenia were also significantly less frequent in patients receiving MLT. Finally, stomatitis and neuropathy were less frequent in the MLT group, albeit without statistically significant differences. Alopecia and vomiting were not influenced by MLT. This pilot study seems to suggest that the concomitant administration of the pineal hormone MLT during chemotherapy may prevent some chemotherapy-induced side-effects, particularly myelosuppression and neuropathy. Evaluation of the impact of MLT on chemotherapy efficacy will be the aim of future clinical investigations.

Prolonged exposure to 5'-N-ethylcarboxamidoadenosine (NECA) does not affect the adenosine A2A-mediated vasodilation in porcine coronary arteries

At present, four distinct adenosine receptors (A1, A2A, A2B, and A3) have been cloned and characterized in several species. It is known that prolonged exposure of tissues to receptor agonists induces A1 receptor desensitization. However, controversial data are reported on whether or not prolonged stimulation of A2A adenosine receptors induces tolerance. Using the porcine coronary artery, a sensitive vascular model, studies were designed, with the aim to clarify how prolonged exposure to the adenosine agonist 5'-N-ethylcarboxamidoadenosine (NECA) affects A2A receptor responsiveness. The arteries were precontracted with PGF2alpha (3 microM) and cumulative dose-response curves to either NECA itself, or the selective A2A agonists, 2-[4-2(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosi ne (CGS 21680) and 2-hexynyl-5'-N-ethylcarboxamidoadenosine (2HE-NECA) were obtained. In separate experiments, coronary rings were incubated with NECA (10 microM) for 30 min or 2 h. After 2 h washout period, functional response was assessed. The arteries showed high sensitivity to adenosine agonist-induced vasorelaxation. EC50 (nM) values were 71.8 (35.5-145), 20.0 (11.2-32.7) and 40.2 (20.4-79.1) for NECA, 2HE-NECA and CGS 21680, respectively. Vasorelaxant response of A2A selective agonists 2HE-NECA and CGS 21680 was not influenced by preincubation with NECA for 30 min or 2 h. Conversely, dose-response curves to NECA were shifted toward the right by preincubation with NECA itself: ED50 (nM) values were 114 (79.2-165), 211 (161-276) and 412 (132-1290) for 30 min, 2 h and 15 h preincubation, respectively. These effects did not occur after 4 h washout. The present results indicate that prolonged stimulation of A2A receptors does not lead to loss of functional response, suggesting that this receptor subtype does not desensitize after prolonged stimulation by agonists.

Macrocystic serous cystadenoma of the pancreas. Diagnostic, therapeutic and pathological considerations of three cases

BACKGROUND

Macrocystic serous cystadenoma (MSC) of the pancreas is a new entity that has recently been well recognised. This tumour is quite similar in aspect to the mucinous cystic tumours (MCT) but its prognosis is much better, so that a correct diagnosis before surgery is important.

PATIENTS

Three patients undergoing surgery in the 1st Surgical Clinic of the University of Bologna for suspected cystic lesions were found to have macrocystic serous cystadenoma (MSC) of the pancreas. In two cases a biopsy was performed during surgery, but in only one was a correct diagnosis of MSC made; in the other the diagnosis was lymphangioma. In the remaining case a biopsy was not performed because the high 19/9 CA level in the blood suggested a diagnosis of MCT of the pancreas. In all 3 cases the tumour was successfully removed by surgery.

CONCLUSIONS

Macrocystic serous cystadenoma (MSC) of the pancreas represents a variant of the serous cystic tumors, which encompass microcystic adenoma and serous cystadenocarcinoma. MSC must be distinguished from MCT because it exhibits a different biological pattern and requires a different surgical approach. Therefore, we would underline the importance of a biopsy in making the differential diagnosis.

Cardioprotective effects of adenosine A1 and A2A receptor agonists in the isolated rat heart

It has been postulated that the adenosine A1 receptor subtype, but also A2a receptors, are involved in mediating the beneficial properties of adenosine during ischemia and reperfusion. We investigated the effects of the selective A1 adenosine receptor agonist, 2-chloro-N6-cyclopentyladenosine (CCPA), the selective A2A adenosine receptor agonists, 2-[p-(2-carboxyethyl)phenetylamino]-5'-N-ethylcarboxamidoadenosine (CGS 21680), 2-hexynyl-5'-N-ethylcarboxamidoadenosine (2HE-NECA), and the non selective agonist, 5'-N-ethylcarboxamidoadenosine (NECA), on ischemia-reperfusion injury in Langendorff-perfused rat hearts. Global ischemia was induced for 15 min in paced hearts followed by 60 min reperfusion. Control hearts developed left ventricular dysfunction, as indicated by the increase in end diastolic pressure to 40.8 +/- 5.1 vs 5.9 +/- 1.0 mm Hg baseline, and in coronary perfusion pressure to 57.6 +/- 8.4 vs 28.8 +/- 2.2 mm Hg before ischemia. After 15 min of reperfusion, ventricular function (LVDP) recovered by 83%, but creatine kinase levels were still significantly increased (294 +/- 55 IUl(-1) vs basal), indicating the occurrence of myocardial injury. All adenosine agonists added to the perfusion medium 15 min prior to ischemia exerted protective effects against myocardial dysfunction and reperfusion injury. Thus, 2HE-NECA (100 nM), CGS 21680 (10 nM), CCPA (3 nM) and NECA (100 nM) significantly (P < 0.05) decreased end diastolic pressure by 50-75% as compared with the control group. Similarly, all compounds significantly (P < 0.05) reduced coronary perfusion pressure by 30-45% vs control. For all drugs, recovery of LVDP occurred immediately after restoration of coronary flow. At 15-min reperfusion the adenosine agonists decreased myocardial creatine kinase release by 80-95% (P < 0.05 vs control). These findings indicate that both A1 and A2A adenosine receptors are involved in protecting the myocardium against ischemia and reperfusion in isolated rat heart, even if through different mechanisms.

Reversal of clinical resistance to LHRH analogue in metastatic prostate cancer by the pineal hormone melatonin: efficacy of LHRH analogue plus melatonin in patients progressing on LHRH analogue alone

OBJECTIVE

Experimental and preliminary clinical studies have suggested that the pineal hormone melatonin (MLT) may stimulate hormone receptor expression on both normal and cancer cells. Moreover, MLT has appeared to inhibit the growth of some cancer cell lines, including prostate cancer, either by exerting a direct cytostatic action, or by decreasing the endogenous production of some tumor growth factors, such as prolactin (PRL) and insulin-like growth factor-1 (IGF-1). On this basis, a study was carried out to evaluate the clinical efficacy of a neuroendocrine combination consisting of the LHRH analogue triptorelin plus MLT in metastatic prostate cancer progressing on triptorelin alone.

MATERIAL AND METHODS

The study including 14 consecutive metastatic prostate cancer patients with poor clinical conditions (median age: 70.5 years; median PS: 50%), refractory or resistant to a previous therapy with the LHRH analogue triptorelin alone. Triptorelin was injected i.m. at 3.75 mg every 28 days, and MLT was given orally at 20 mg/day in the evening every day until progression, starting 7 days prior to triptorelin.

RESULTS AND CONCLUSIONS

A decrease in PSA serum levels greater than 50% was obtained in 8/14 (57%) patients. Moreover, PSA mean concentrations significantly decreased on therapy of triptorelin plus MLT. In addition, a normalization of platelet number was obtained in 3/5 patients with persistent thrombocytopenia prior to study. Mean serum levels of both PRL and IGF-1 significantly decreased on therapy. Finally, a survival longer than 1 year was achieved in 9/14 (64%) patients. This preliminary study would suggest that the concomitant administration of the pineal hormone MLT may overcome the clinical resistance to LHRH analogues and improve the clinical conditions in metastatic prostatic cancer patients.

Melatonin and the immune-hematopoietic system therapeutic and adverse pharmacological correlates

The pineal neurohormone melatonin functionally synchronizes the photoperiod in the organism. In the last decade, it has become increasingly clear that the pineal gland and melatonin also play an important immunoregulatory role. T helper (Th) cells bear G-protein-coupled melatonin receptors. Activation of melatonin receptors enhances the release of Th cell cytokines, such as gamma-interferon and interleukin-2, as well as novel opioid cytokines which cross-react immunologically with both interleukin-4 and dynorphin B. These mediators may counteract secondary immunodeficiencies, protect mice against lethal viral and bacterial diseases, synergize with interleukin-2 in cancer patients and affect hematopoiesis. Hematopoiesis is apparently influenced by the action of melatonin-induced opioids on kappa-opioid receptors present on stromal bone marrow cells. Most interestingly, gamma-interferon and colony-stimulating factors may modulate the production of melatonin in the pineal gland. A hypothetical pineal-immune-hematopoietic network is, therefore, taking shape. From the immunopharmacological point of view, there is a need for clinical studies on the effect of melatonin in human immunodeficiency-virus-infected patients and cancer patients. In conclusion, melatonin seems to be an important immunomodulatory hormone which deserves to be further studied to identify its relevance in immune-based diseases, its therapeutic indications and its adverse effects.

Melatonin-induced T-helper cell hematopoietic cytokines resembling both interleukin-4 and dynorphin

We have reported that melatonin exerts colony stimulating activity and rescues bone marrow cells from apoptosis induced either in vivo or in vitro by cancer chemotherapy compounds. We proposed that melatonin regulates interleukin-4 (IL-4) production in bone marrow T-helper cells and that IL-4 stimulates adherent stromal cells to produce colony stimulating factors (CSF). However, in further investigations we did not find any direct evidence of the ability of melatonin to stimulate IL4. We found that besides anti-IL4 monoclonal antibody (mAb), the opioid antagonist naltrexone also neutralized the colony stimulating activity and part of the hematopoietic protection exerted by melatonin. SDS-PAGE and immunoblotting analysis of supernatants of bone marrow T-helper cells incubated overnight with melatonin revealed the presence of two proteins with an apparent molecular weight of 15 and 67 kDa, which were recognized by both anti-common opioid sequence (Tyr-Gly-Gly-Phe) and anti-IL4 mAbs. When Abs against known opioid peptides were tested, only anti-dynorphin B Ab labeled the 67 kDa but not the 15 kDa protein. These melatonin-induced-opioids (MIO) were separated by gel filtration. The lower molecular weight MIO (MIO15) seems to mediate the naltrexone-sensitive hematopoietic effects of melatonin. Consistently, we found the presence of opioid receptors in adherent bone marrow cells. Apparently, the higher molecular weight protein, MIO67, was responsible for the naltrexone-insensitive part of the melatonin-induced hematopoietic rescue. These melatonin-induced T-helper cell products which resemble both IL-4 and dynorphin B might represent a new family of opioid peptides with hematopoietic and immune functions.

Melatonin in human breast cancer tissue: association with nuclear grade and estrogen receptor status

The pineal hormone melatonin has been reported to inhibit tumor growth in a variety of experimental and clinical situations and to be an important immunoregulatory agent. Cancer patients with mammary or prostate tumors show reduced levels of circulating melatonin. Melatonin might, thus, be involved in the development of the malignant disease and act directly on tumor cells. Melatonin concentration in human neoplastic and adipose tissue sampled from mastectomy or tumorectomy products (n = 15) was measured by high-performance liquid chromatography. Melatonin seemed to be 3 orders of magnitude more concentrated in the neoplastic and adipose tissues of the breast than in sera from healthy subjects or cancer patients. Few samples (n = 3) of normal breast tissues showed equally elevated concentrations of melatonin. Most interestingly, we found a significant inverse correlation between nuclear grade and melatonin concentration (p < 0.006) and a positive association between melatonin and estrogen receptor status (p < 0.02). No correlation between age of the patients and melatonin concentration was evident. Melatonin might be produced in situ by mammary epithelial cells and represent a good prognostic marker. The possibility that exogenous melatonin might influence nuclear grade and/or estrogen receptor activity in breast cancer patients should be investigated.