Proteasomal RNase activity in human epidermis

The proteasome is a cytoplasmic high-molecular-weight structure composed of several smaller protein and RNA subunits. It has been associated with non-lysosomal pathways of intracellular degradation, expressing multicatalytic proteinase activities and specific RNase activity. By standard methods, we have isolated andpartially purified proteasomes from human epidermis. We obtained the expected multiple 24-32 kDa subunits by SDS-PAGE, and evidence of RNA. Proteasomes degraded casein, as well as chromogens for t-PA and trypsin but not for chymotrypsin, these proteolytic activities overlap, but do not coincide with those observed in other organs. We found that human epidermal 28 S and 18 S rRNAs were degraded, but yeast RNA was not. By means of zymography, we demonstrated, for the first time, that RNase activity persists after dissociation of the proteasome on the gel and that it co-localizes to the same range of molecular weight subunits as the proteinase activity.

The effects of REM sleep-inhibiting drugs in neonatal rats: evidence for a distinction between neonatal active sleep and REM sleep

Neonatal active sleep (AS) has been considered to be homologous and continuous with rapid-eye-movement (REM) sleep in adult animals. We have recently proposed an alternative view that AS is an undifferentiated sleep state distinct from REM sleep. To test these opposing views on the relationship of AS and REM sleep, neonatal rats (P11, P14 and P20) were systemically injected with compounds that inhibit REM sleep in adults. Zimelidine (ZMI) and desipramine (DMI) are monoamine uptake inhibitors which increase synaptic concentrations of serotonin and norepinephrine, respectively. Serotonin and norepinephrine inhibit brainstem cholinergic neurons important in REM sleep generation. Atropine (ATR) is a muscarinic receptor antagonist that blocks the post-synaptic effects of cholinergic projections. Only DMI (5 mg/kg) suppressed AS at P11. ZMI (6 mg/kg) and ATR (6 mg/kg) did not suppress AS until P14. These data suggest that serotonergic and cholinergic regulation of AS are absent before P14. The fact that AS in P11 rats is not affected by cholinergic antagonists supports the hypothesis that AS and REM sleep represent different sleep states.

An approach to the neonate with sudden dysrhythmia: diagnosis, mechanisms, and management

The clinical course of a newborn can be rendered more complex by the sudden development of a disturbance in heart rhythm and conduction. The caregiver's ability to recognize a particular dysrhythmia and its most probable mechanism is crucial for optimal management. During the past 15 years, there has been significant progress in the understanding of the electrophysiologic basis of rhythm disturbances in the newborn period. This understanding has led to more precise diagnosis and effective treatment regimens for infants with dysrhythmias. Using recent case studies from one intensive care nursery as illustrations, this article discusses the clinical presentation and electrophysiologic mechanisms of three common forms of rhythm and conduction disturbance. The discussion pertains to disturbances of rhythm in association with tachycardia only. Emphasis is placed on the electrocardiographic diagnosis and clinical management of these infants.

Consumption of non-steroidal anti-inflammatory drugs and the development of functional renal impairment in elderly subjects. Results of a case-control study

AIMS

The aim of the present study was to explore the level of risk associated with community use of non-steroidal anti-inflammatory drugs (NSAIDs).

METHODS

We carried out a matched case-control study of the relationship between recent use of NSAIDs and the presence of functional renal impairment present at the time of hospitalisation with a range of clinical problems. Cases (n = 110) were consecutive patients admitted acutely to hospital who had serum creatinine levels greater than or equal to 0.15 mmol l(-1) , which improved by 20% or more within the next 14 days, or prior to discharge from hospital. Controls (n= 189) were subjects of the same sex and age (to within 5 years) as the cases, who were admitted to the same hospital, who had normal serum creatinine levels (<0.12 mmol l(-1) throughout their hospital stay. Information on a number of study factors, including recent use of aspirin and other NSAIDs, was obtained by structured interview.

RESULTS

Overall, there was a weak association between consumption of NSAIDs (including non-prophylactic aspirin) and the development of functional renal impairment-adjusted odds ratios (OR) with use of NSAIDs in the previous week or in the previous month: OR 1.5 (95% CI 0.80, 2.9) and 1.8 (95% CI 0.97, 3.4) respectively. In subjects with a previous history of renal disease the adjusted OR was 6.6 (0.75, 57.8) and in those with a history of gout or hyperuricaemia the OR was 7.2 (1.3, 40.2). There was a weak positive relationship between the dose of drug consumed in the previous week and the odds of functional renal impairment. The relationship between risk and published figures for drug half-lives (t1/2) was stronger. The odds ratio increased from 1.2 (95% CI 0.61, 2.4) with a t1/2 < or = 4 h, to 4.8 (1.5, 15.8) with a t1/2 of < or = 12 h (P=0.012, test for trend). This relationship remained statistically significant after adjustment for a number of clinical variables and the dose of drug ingested.

CONCLUSIONS

NSAIDs are an important cause of functional renal impairment in subjects with renal disease or a history of gout or hyperuricemia. The half-life of the drug is more important than the ingested dose in determining the risk of this outcome. Long half-life drugs should be avoided in individuals who are at risk of developing renal impairment.

Improved quality of life with megestrol acetate in patients with endocrine-insensitive advanced cancer: a randomised placebo-controlled trial. Australasian Megestrol Acetate Cooperative Study Group

PURPOSE

To investigate the effect of two doses of megestrol acetate (MA) compared with placebo on quality of life (QoL) and nutritional status (NS) in patients with advanced endocrine-insensitive cancer.

PATIENTS AND METHODS

Two hundred forty patients were randomised to double-blind MA 480 mg/day, MA 160 mg/day, or matching placebo for 12 weeks. Nutritional status (including weight, skinfold thickness and midarm circumference) and QoL (using 6 linear analogue self-assessment (LASA) scales) were assessed at randomisation and after four, eight and 12 weeks. A QoL ranking incorporating QoL and death was also used ranging from 1 = dead to 5 = much better QoL.

RESULTS

One hundred seventy-four patients were assessable at week four, 136 at week eight and 103 patients at week 12. Patients receiving MA reported substantially better appetite (P = 0.001), mood (P = 0.001) and overall quality of life (P < 0.001), and possibly less nausea and vomiting (P = 0.08) than patients receiving placebo, based on a test for trend. A larger benefit was seen with the higher dose which (unlike the lower dose) was significantly better in pairwise comparisons with placebo for appetite, mood and overall QoL (each P < or = 0.001). Despite some missing data on QoL scores, QoL ranking was available on 227 (95%) of patients with significantly higher QoL ranking associated with MA (P = 0.002). Improvements in QoL occurred early within four weeks and were sustained. No statistically significant differences were observed in NS measurements, including weight (P = 0.29). Side effects of therapy were minor and did not differ significantly across treatments.

CONCLUSION

Megestrol acetate given at 480 mg/day is useful palliation in patients with endocrine-insensitive advanced cancer. It improves appetite, mood and overall quality of life in these patients, although not through a direct effect on nutritional status.

Meiotic behaviour of holocentric chromosomes: orientation and segregation of autosomes in Triatoma infestans (Heteroptera)

The meiotic behaviour of the holocentric chromosomes of the heteropteran species Triatoma infestans has been analysed by means of orcein staining and C-banding on squashed spermatocytes. We have focused our analysis on chromosome 3, which shows a large distal heterochromatic band at one of the ends of both homologues. At metaphase I, and independently of the chiasma position, two alternative orientations have been observed: either the heterochromatic or the euchromatic ends of both homologues are directed to opposite poles. At anaphase I, the kinetic activity is restricted to the same chromosome end (euchromatic or heterochromatic) of each homologue. The frequencies of these two alternatives are not random and differ significantly among the five individuals analysed. However, the euchromatic ends present kinetic activity at a higher frequency than the heterochromatic ends. At metaphase II, half-bivalents also show the kinetic activity restricted to either of the chromosome ends (euchromatic or heterochromatic). The frequencies of each alternative are inverted in anaphase II compared with those scored in anaphase I. Accordingly, those ends that present kinetic activity at anaphase I segregate reductionally during the first meiotic division and equationally during the second meiotic division. These results provide sound evidence on the meiotic behaviour of holocentric chromosomes, as regards the absence of chiasma terminalization and the modes of orientation and segregation.

Management of hormone-resistant prostate cancer: an Australian trial

The management of metastatic prostate cancer that has relapsed after initial hormonal manipulation remains a major problem, with the majority of patients dying within 12 months. Their clinical course is frequently characterized by progressive debilitation, pain, and other tumor-related symptoms. A phase II, non-randomized multicenter clinical trial was carried out in Australia in 1985-1986 to assess the efficacy and toxicity of mitoxantrone. Substantial anticancer activity was shown against hormone-refractory prostate cancer, indicated by reduction in tumor-related symptoms, improvement in quality of life indices, and a median survival of 10 months in patients with a heavy tumor burden. Although it is not possible to equate this nonrandomized series more fully with current experience since routine prostate-specific antigen measurement was not performed, the median survival of 10 months was equivalent to or better than the survival times reported from most other institutional reports of the time. Even more importantly, however, major improvements were noted in such subjective indices as reduction in pain, weight gain, and performance status. Toxicity was also acceptable, with the major side effect being asymptomatic myelosuppression.

The osmium tetroxide-p-phenylenediamine procedure reveals the chromatid cores and kinetochores of meiotic chromosomes by light and electron microscopy

We analyzed first-metaphase meiotic chromosomes of the grasshopper Chorthippus jucundus by two different methods, i.e., a silver impregnation technique and the osmium tetroxide-p-phenylenediamine (Os-PPD) procedure. The former was applied on squashed testes previously fixed in ethanol-acetic acid, whereas for Os-PPD the material was not subjected to any previous extraction treatment but was fixed in OsO4, treated with PPD, and embedded in Epon 812. Both techniques revealed chromatid cores and kinetochores regardless of the processing of the material (squashed or sectioned). Unstained Os-PPD sections were analyzed by light microscopy and transmission electron microscopy (TEM). The Os-PPD technique provided a high contrast of chromatid cores and kinetochores in relation to the chromatin, which revealed a low electron density. To determine the Os-PPD reaction mechanism, the PAS procedure, as well as scanning electron microscopy (SEM) backscattering and SEM X-ray microanalysis, was performed on sections. By use of the Os-PPD-PAS procedure, glycol groups formed by oxidation of osmium bound to aromatic substrates were detected in chromatid cores and kinetochores by brightfield and fluorescence microscopy. A high Z contrast was detected in these structures by backscattered electron imaging. SEM X-ray microanalysis showed osmium and phosphorus to be the main elements present on the chromatid cores. Taking into account the known reactivity of OsO4 and the present results, the possible participation of nucleic acids as well as proteins in the Os-PPD reaction mechanism and in the composition of chromatid cores and kinetochores is discussed.

The quantitation of coupled bead antibody by enzyme-linked immunosorbent assay

Quantitation of antibody coupled to a derivatized polystyrene bead through a bifunctional cross linker can be accomplished by a competitive enzyme-linked immunosorbent assay (ELISA) method. This sensitive method is less subject to interference than other protein assay methods such as bicinchoninic acid (BCA) or Lowry. The competitive ELISA method consists of incubating the coupled bead with a (20/80) weight ratio of goat anti mouse kappa alkaline phosphatase/goat anti mouse kappa (GAMKAP/GAMK) for 1.5 hours at 37 degrees C, washing, adding p-nitrophenyl phosphate (PNPP) substrate, and reading the absorbance at 405/450 nm. A standard curve is established with radiolabeled antibody beads for microgram quantitation.

The newborn with ambiguous genitalia

This article reviews the normal embryological process of sex determination and differentiation, along with classifications of abnormalities of sex differentiation. It also outlines an approach to the diagnostic evaluation and gender assignment in infants with ambiguous genitalia and discusses implications for nursing care of these infants and their families.

Developmental outcome of infants treated with extracorporeal membrane oxygenation (ECMO) in the neonatal period: is the evidence all in?

The North American literature was reviewed regarding the developmental outcome of infants treated with ECMO therapy versus those infants who received conventional medical therapy for treatment of persistent pulmonary hypertension of the newborn. The literature reviewed included all ECMO follow-up investigations published in medical journals cited in CD-ROM between January 1980 and July 1992, as well as abstracts presented at the Society for Pediatric Research 1990-1992. The literature was examined with respect to the incidence, prevalence and nature of morbidity, with particular attention paid to the neuroevelopmental domains assessed, test measures used, age at assessment and criteria for normal and abnormal outcome. Rough comparison of the published outcome statistics for the cohorts of infants who received neonatal ECMO therapy or conventional medical therapy (CMT) suggest equivalent amounts of morbidity within the first few years of life. Without appropriate systematic comparison at the same ages on the same measures and in infants with equivalent severity of illness, the current observations remain tentative at best. Longitudinal investigations are needed in order to identify specific medical and developmental markers in infancy of good and poor long-term outcome in this population, together with comparisons of outcome in the group treated with ECMO versus the group treated with CMT. Fine-grained, sensitive measures must be employed that record transient or permanent delays and/or qualitative deficits in specific skills.

Factors influencing medical interns trained at U.W.I. to work subsequently in a rural area in Jamaica

Recognising the present paucity of doctors trained at the University of the West Indies who are working in rural government health facilities in Jamaica, and its impact on the health services, this study was done to determine the factors influencing the decision of UWI-trained interns to work in these facilities post-internship. A questionnaire was administered to 57 UWI-trained medical graduates presently doing their internship in Jamaica. The results showed that there was no significant difference in the choice of placement with respect to sex, or residential background of the intern, though the latter seemed to indicate a trend. Of those who thought they would work in a rural government health facility, two-thirds would do so immediately post-internship but 50% did not plan to work there for more than five years. Opportunities for postgraduate training and lack of equipment were the most important deterrents to working in a rural government health facility.

An extraskeletal chondrosarcoma arising in the brachial plexus

A case of extraskeletal chondrosarcoma of the left brachial plexus is described with emphasis on the diagnostic and therapeutic difficulties of this site. With combination therapy the patient survived 6 years. Recurrent disease in the plexus region and adjacent spinal cord resulted in a painful, flail limb.