Trypsin-mediated semisynthesis of salmon calcitonin

Salmon calcitonin, CT(1-32)·NH₂, was synthesised by the trypsin-mediated coupling of the peptide fragments CT(1-24) and CT(25-32)·NH₂, prepared by conventional Fmoc solid-phase chemistry. Optimal conditions regarding reaction time course, pH, proportion of catalyst, substrate concentration and composition of the reaction medium were determined from initial studies on the coupling of CT(1-11) to CT(12-24) and of CT(12-24) to CT(25-32)·NH₂. For the final successful semisynthesis, we found that it was unnecessary to protect lysine residues not involved in the coupling, and that secondary hydrolysis at these sites could be prevented by increasing the pH of the reaction medium. The reaction achieved equilibrium after 30-45 min, with overall conversion of around 30% of the initial amount of CT(1-24) substrate into product. Yields were depressed due to cyclisation of the CT(1-24) substrate via air-oxidation of the Cys¹ and Cys⁷ residues.     

Are infantile myofibromatosis,congenital fibrosarcoma and congenital haemangiopericytoma histogenetically related?

Infantile myofibromatosis, congenital fibrosarcoma and congenital/infantile haemangiopericytoma are generally considered distinct entities. Overlapping microscopic features between infantile myofibromatosis and congenital fibrosarcoma, and between infantile myofibromatosis and congenital/infantile haemangiopericytoma, however, have been noted, but not formally reported. This report concerns six neonatal tumours, each exhibiting more than one of the above patterns, supporting a histogenetic relationship among these entities. Immunohistochemistry for smooth muscle actin was found to be useful in the diagnosis of congenital/infantile haemangiopericytoma, and also served to support a histogenetic relationship with the other two entities under consideration.     

Electromyographic parameters related to clenching level and jaw-jerk reflex in patients with a simple type of myogenous cranio-mandibular disorder

A discriminant analysis has been applied on several electromyographic (EMG) parameters of the masseter and the anterior temporal muscles, related to clenching and the jaw-jerk reflex, to characterize jaw muscle function of patients with craniomandibular disorder (CMD) with respect to controls. The subject samples, matched for age, consisted of 20 females with myogenous CMD, and 20 symptom-free females. The jaw-jerk reflex was elicited by a downward-directed mandibular load, transmitted by a bite-fork causing a similar occlusion and bite-rise as a splint. The patients differed mainly from the controls by smaller maximum EMG activity in both muscle groups (P less than 0.05 with the bite-fork inserted). This finding was related to a smaller muscle strength as the EMG level did not improve with pain-free jaw muscles after therapy using a relaxation splint. Discriminating factors of secondary importance were an enhanced bilateral asymmetry in the muscle activity of the patients, and in the reflex amplitude normalized for background EMG activity. In all subject samples, the activity of the anterior temporal muscles decreased with respect to the masseter muscles when the bite-fork was inserted (P less than 0.05-0.001). The therapeutic effect of a relaxation splint may, in part, be related to a relief of the temporal muscles.     

Kinetics and Specificities of the T Helper–Cell Response to GP120 in the Asymptomatic Stage of HIV–1 Infection

Peripheral blood mononuclear cells from 36 asymptomatic HIV-1 seropositive individuals were tested longitudinally for in vitro T–cell proliferation and IL–2 production in response to synthetic peptides spanning the entire gp120 of HIV–1. At baseline, significant T–cell proliferation to pooled and individual peptides was observed in 15 of the 36 donors. After 12 months, proliferate responses to peptide pools were lost or decreased significantly in most donors. Responses appeared to fluctuate over time: at 12 months new recognition sites were detected in four of 10 donors showing T–cell proliferation at baseline, as well as in five of 15 donors with no previous proliferative responses. IL–2 production appeared to be a more sensitive and longer preserved parameter of T–helper cell function: at baseline the majority of donors with no T–cell proliferation produced IL–2 in response to pooled peptides. This response was not decreased significantly after 12 months. The overall patterns of response to both pooled and individual peptides were heterogeneous among donors. Multiple recognition sites were detected in both variable and conserved regions of gp120, but no pool or individual peptide was recognized by all responders. Functional T–cell responses were not statistically correlated to CD4° cell percentile and absolute numbers.     

In vitro dissolution rates of six 8-methoxypsoralen formulations

Dissolution rates in water of six oral 8-methoxypsoralen formulations were determined with both the rotating basket method and a column type flow-through method. Comparable and reproducible results were obtained with both methods. In view of the necessity in psoralen-UVA (PUVA) therapy that effective tissue concentrations of the drug be present in the skin during the irradiation period, we propose a requirement for a dissolution rate of 8-MOP tablets or capsules of at least 80% within 25 min. None of the three preparations registered in The Netherlands met this requirement. However, two preparations from abroad and a new capsule formulated in our pharmacy department with solid 8-MOP dispersed in polyethylene glycol 6000 showed satisfactory dissolution profiles.     

THE RELATIONSHIPS BETWEEN SERUM T3 INDEX, THYROID VOLUME, AND THYROID STIMULATING, TSH RECEPTOR BINDING AND THYROID GROWTH STIMULATING ANTIBODIES IN UNTREATED GRAVES'' DISEASE

High plasma concentrations of neuropeptide Y (NPY) were found in a patient with bilateral adrenal phaeochromocytomas and medullary thyroid carcinoma associated with MEN IIa (32 pmol/l, normal less than 3.5 pmol/l). Both adrenal tumours contained and secreted NPY. Manipulation at operation produced a remarkable increase in plasma NPY concentrations (peak = 1631 pmol/l) coinciding with increases in plasma levels of catecholamines and arterial pressure. NPY was also shown to be present in thyroid tumour tissue: the concentration of NPY in tumour was 50-fold higher (0.9 nmol/g vs 0.004 nmol/g) than in adjacent normal thyroid tissue. It is possible that NPY from some phaeochromocytomas may contribute to hypertension during surgery.     

The need for assessment of sensory functioning in ageing people with mental handicap

ABSTRACT. Within the framework of a study on the ageing process of people with mental handicap in the Netherlands, information about visual and hearing impairments in 1583 people with mental handicap living in group homes or institutions was obtained from their physicians by means of a written questionnaire. Of the people with Down's syndrome (DS) who were older than 50 years of age, 46% had a visual impairment, whereas approximately 13% of subjects with other causes of mental handicap at the same age experienced similar visual impairment. Hearing loss in this age group was reported in 28% of people with DS, but only in 8% of subjects with other causes of mental handicap. The most common eye condition was cataracts, and the most frequent cause of hearing impairment was infection. In people with severe and profound mental handicap of all ages, sensory impairments were more frequent than in persons with mild or moderate mental handicap. Glasses or hearing aids were rarely used by people with severe or profound mental handicap. Assessment of visual and hearing impairments in people with mental handicap seemed clearly indicated, especially in those aged 50 years and older, in those with DS, and in those with severe or profound mental handicap.     

Scintigraphic visualization of intrathecal liposome biodistribution

Background: Liposomes containing local anaesthetics have been administered intrathecally and in the epidural space. Poor attention has been given to the pharmacokinetics of liposomes as drug carriers. Therefore, we observed the biodistribution of liposomes after intrathecal injection in rats by scintigraphic imaging during 24 h.
Methods: We administered ⁹⁹Tc-labeled multilamellar (MLV) and small unilamellar vesicles (SUV) of defined size and volume dispersities into the cerebrospinal fluid at the lumbar level. Those vesicles were free of contamination by radiolabeled colloids as visualized by light and electron microscopy and of neurotoxic products from phosphatidylcholine hydrolysis and peroxidation, both during the preparation process and after 24 h incubation in cerebrospinal fluid at 37°C in vitro.
Results: SUV immediately diffused from the lumbar site of injection to the head and were cleared between 1 and 24 h after injection. MLV were cleared more slowly from the spinal space and appeared in the head region 1 h after injection where they accumulated up to 24 h. These differences were explained in terms of vesicle sizes and volumes. SUV with 0.05 μm diameters were rapidly absorbed into the blood through the arachnoid granulations. In contrast, particles larger than the upper size limit of the arachnoid granulations permeability (±8 μm) could accumulate in the head with a slow elimination rate.
Conclusion: This difference in clearance from the intrathecal space outlines the importance of defining the size of the liposomes, the distribution of a tracer or a drug inside the liposomal preparation, the chemical stability and the absence of toxic degradation products of liposome formulations before clinical use.     

COMPARISON OF NITROGLYCERINE, VERAPAMIL AND NIFEDIPINE IN THE MANAGEMENT OF ARTERIAL PRESSURE DURING CORONARY ARTERY SURGERY

The efficacy of nitroglycerine, verapamil and nifedipine incontrolling post-sternotomy hypertension was compared in fourgroups of 20 patients anaesthetized with fentanyl 100 µgkg^–1 undergoing elective coronary artery surgery. Vasodilatorswere started before surgery and adjusted to maintain systolicarterial pressure < 120% of pre-infusion values, the mean(±SEM) requirements being: nitroglycerine (group II)3.6±0.6 µg kg^–1 min^–1; verapamil groupIII) 31.1 ±2.6 µg kg^–1 min¹ nifedipine (groupIV) 1.7±0.2 µg kg^–1 min^–1 Systolicpressure decreased significantly by 5 min after starting infusionsin groups II and III. In the control group (I: no vasodilator)arterial pressure increased significantly following skin incisionand sternotomy. Pulmonary arterial and capillary wedge pressuresincreased significantly following sternotomy in groups I andIII. Heart rate increased after sternotomy in all groups, butonly reached significance in groups III and IV. There were nosignificant changes in cardiac index or vascular resistance,although the latter remained lower than pre-infusion valuesat all times in groups III and IV. The P-Q interval increasedsignificantly in group III. It is concluded that nifedipineis a suitable alternative to nitroglycerine for the controlof arterial pressure during coronary artery surgery, but verapamilis not recommended because of its negative inotropic effectand its depressant effect on A-V conduction.